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Bulletin of the Museum of Gohnacative apoE at Harvard College, CAMBRIDGE, Mass. Vor TV.
THE TERRESTRIAL
AIR-BREATHING MOLLUSKS
OF THE
UNITED STATES AND THE ADJACENT TERRITORIES OF NORTH AMERICA.
DESCRIBED AND ILLUSTRATED
By W. G. BINNEY.
VOL.YV.
CAMBRIDGE: PRINTED BY WELCH, BIGELOW, AND COMPANY, UNIVERSITY PRESS. JULY, 1878.
613322 a eee
PREFACE.
AutnoueH this work forms a fifth volume to the “ Terrestrial Mollusks of the United States,” * I have endeavored to make it a complete manual of the subject. With this view, I have compiled from the writings of my father, my friend Mr. Bland, myself, and other authors all their more important portions, not only of descriptions and figures of species, but of all that relates to the Habits of the Animals, their Geographical Distribution, their Jaw and Lingual Membrane, their Anatomy, and their Classification. I devote no space to Bibliography, referring to my gen- eral work on that subject published by the Smithsonian Institution.
In the descriptive portion it will be seen that I have usually adopted the descriptions of genera and subgenera of Albers and Von Martens. From the same authors I have also usually adopted the generic and sub- generic names, without inquiry into their precedence, having neither time nor inclination to attempt myself to disentangle the confused synonymy.
In the synonymy of the species I have quoted only authors giving an original description or an original figure. I have personally consulted all the references, unless otherwise specified.
The subject is brought down to January, 1878. The plates of Vol. III. are reproduced. Those of Vols. I. and IV. I regret not being also able to give. In the references to plates in the text it must be remembered
* The Terrestrial Air-breathing Mollusks of the United States and the adjacent Territories of North America: described and illustrated by Amos Binney. Edited by Augustus A. Gould. Boston, Charles C. Little and James Brown. Vols. I, II. MDCCCLI.; Vol. III., Plates; MDCCCLVII.; Vol. IV. by W. G. Binney, New York, B. Westermann, MDCCCLIX., from Boston Journal of Natural History, Vol. VII.
a
iv PREFACE.
that figures of shells are included in the copperplates of Vol. III., while those of genitalia and lingual dentition are to be found exclusively in the lithographic plates now first offered. ‘Thus there is a double system of plates.
In addition to those mentioned in the first and fourth volumes, I am indebted for assistance in the preparation of this to Dr. J. G. Cooper, Haywood, Alameda County, Cal.; Miss Annie M. Law, Philadelphia, Tenn. ; Mr. W. G. Mazyck, Charleston, S. C.; Prof. A. G. Wetherby, Cin- cinnati, O.; Mr. O. B. Johnson, Forest Grove, Or.; Mr. Henry Hemphill, San Diego, Cal. ; Mr. Sam. Powell, Newport, R. I. ; Mr. G. W. Tryon, Philadelphia, Penn. ; Mr. F. Stein, Mt. Carmel, Ill. ; Mr. H. S. Crooke, N. Y.; Mr. A. T. E. Lansing, Watertown, N. Y.; Mr. R. E. C. Stearns, San Francisco, Cal. ; Dr. W. H. Dall, Washington, D. C.; Mr. W. W. Calkins, Chicago, Il.; Mr. J. Gwyn Jeffreys, London; Mr. R. M. Byrnes, Cincinnati, O.; Mr. Anson Allen, Orono, Me. ; Mr. A. W. Crawford, Oakland, Cal.; Mr. Arthur F. Gray, Danversport, Mass. ; Mr. Charles Dury, Cincinnati, O.; Dr. C. A. Millar, Cincinnati, O.; Mr J. T. Crans, Indianapolis, Ind.; Miss Lizzie Taylor, St. Paul, Minn.; Dr. L. G. Yates, California; Mr. J. Matthew Jones, Halifax, N. S.; Mr. E. Ingersoll, Jersey City, N. J.; Mr. W. G. W. Harford, San Francisco, Cal. ; Dr. J. B. Elliott, Sewanee, Tenn.
To Mr. Bland I am indebted for a continuation of the kindness which has so greatly aided me during more than twenty years.
W. G. BINNEY. Buruineron, N. J., June, 1878.
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CONTENTS.
PAGE PREFACE ; F ; ; ; j } ; j : . -*) ae I. Hapirs AND FACULTIFS ; ; ; ; ; : , 1 II. GEOGRAPHICAL DIsTRIBUTION : : P ; R 4 ee Ill. Jaw aAnp LINGUAL MEMBRANE . : : : : . 4] IV. Sprcran ANATOMY . ; ; : u 4 ; ; i ee V. CLASSIFICATION. : ; . ; . : : 76 VI. Systematic INDEX . ‘ ; : : . : , Paes & Vil. Descriptions. F . . : : : . ; , : 80 VII. SuprLeMentT J : : : : ' : ‘ F 3° 482 IX, “Inpax". . . ‘ ; " : ; Z : 433 X. EXPLANATION OF PLATEs oF VoL. JII. . E F ; « Sat
XI. EXPLANATION OF PLATES OF VOL. V. : : 445
TERRESTRIAL AIR-BREATHING MOLLUSKS OF THE UNITED STATES.
I. HABITS AND FACULTIES.'
THE animals of this order, indigenous to the United States, are essen- tially inhabitants of the forest. It is there, under the deep shadows of a dense foliage, where the sun’s rays hardly penetrate to the surface of the earth, and where the ground is covered with the mouldering trunks of trees and thick layers of decaying leaves, that they find a constant moisture, a twilight interrupted only by darkness, abundance of vegeta- ble and animal food, and the means of shelter and protection. These constitute a combination of circumstances very favorable to their in- crease, and hence they may be discovered, in situations where these con- ditions exist, in every part of the country where they can be found at all. But when, with these, are conjoined a mild climate and a calcareous soil, the maximum of favoring influences is reached, and large numbers are produced. It is in the great valley of the Mississippi, based through- out nearly its whole extent upon horizontal limestone formations, that these combined causes operate over an extensive region, and there, con- sequently, the species proper to it exist in multitudes. In the parts of the country which have been long cultivated, and are nearly deprived of their forests, they have mostly disappeared, and only survive in places where some shelter of wood or stones is still afforded to them. They everywhere avoid cultivated fields and open pastures, and are never found in gardens,” or about or within houses or other buildings,
1 [ have reproduced Chapter X. of Vol. I., adding to and modifying it in several par- ticulars when required by my more recent experience and investigations.
21 have in the text already modified this assertion of my father. The instance he gives in his note of ‘‘an exception to this remark in Helix fallax, Say (= Hopetonensis), which we observed a few years since living in great numbers in gardens in Charleston, S. C., in company with Bulimus decollatus,” is by no means single. In every country town and even city some species is sure to be found numerous in gardens and especially in cemeteries, and once having gained a foothold bids fair to retain it. In Burlington, N. J.
VOL, Iv. l
2 TERRESTRIAL AIR-BREATHING MOLLUSKS.
excepting in cases where specimens have been accidentally introduced and remaining undisturbed have multiplied into a colony. In this re- spect they present a remarkable contrast to some of the same animals in Europe, which not only are very common in open and cultivated tracts, but are particularly numerous in fields and gardens, where some of the species commit much mischief, and in‘cellars, drains, and other similar situations, in immediate contiguity with man. The species which have been introduced from Europe, and naturalized in this country, are dis- tinguished by the same habits as the stock from which they are derived, and differ as much from the native species. Thus, Zachea hortensis lives in open and exposed situations destitute of shelter, except that afforded by grass and shrubs; Zonites cellarius occupies gardens and cellars ; Limax flavus inhabits cellars and damp places about drains ; and ZL. agrestis is common everywhere in gardens, fields, cellars, and houses. It infests the roadside, and the neighborhood of our dwellings, and has in some places become the pest of the horticulturist.
:. Whether this difference of habitat arises from original constitution, or is the consequence of the long-continued operation of external causes, is a curious subject of inquiry. The preference for the forest over the open country exhibited by the native species, even in situations where both have been for a long time equally accessible to them, seems to indicate that the former supposition is correct ; and this opinion is strengthened by the disappearance of nearly every species with the progress of agri- culture. If their habits were not insuperable, they might be expected to have been somewhat modified ere now, and to have become adapted to the new physical conditions to which they are subjected. That they have not been, suggests the thought that, like the aboriginal race of men, and some of the larger quadrupeds, they are destined to give way before the advance of civilization, and to have their places filled by for- eign species. On the other hand, there are some facts which tend to show that accidental causes may have produced a slow and gradual rey- olution in the habits of the European species, corresponding with the changes, which, within the historical period, have taken place over the surface of the greater part of Europe; and that in process of time the same influences will produce similar results on the habits of the North American species. All those parts of Europe which are now the most
the most common species is Patula alternata, Zonites arboreus, and Limax campestris. In Savannah it is riodopsis appressa ; in Norfolk, Va., it is Mesodon albolabris ; in Macon, Ga., it is M. major. The original introduction was no doubt accidental.
HABITS AND FACULTIES. 3
populous were ‘covered with forests at no very distant period, and all the terrestrial mollusks were then, like ours at the present time, living in the forest. The progress of agriculture there was very slow com- pared with its advances in this country, and thus time was given to the animals to accustom themselves to the change ; and they have thus, by slow degrees, adopted their present habits.'| In the United States the advance of agriculture in newly settled parts is very rapid; large tracts of forest are almost simultaneously subjected to the axe and to fire, and a very few years produce an entire change in the vegetation of a whole section. Consequently these animals are at once exterminated, or the few that survive are brought suddenly under the influences of new cir- cumstances, which, from the abruptness of the change, are fatal to them, but which, if imposed upon them more gradually, might have been sustained. A few spots and some limited tracts of land, remaining unchanged in the midst of cultivation, protect some individuals of every species ; and it is from this comparatively small number, thus preserved, that their subsequent increase is derived. But at this period the field is equally open for the multiplication of those foreign species which accompany man as for the native species, and it is not surprising that the former, whose habits are already adapted to the existing state of things, should increase more rapidly than the latter. The native species, however, become gradually familiarized with the circumstances around them, and some few of them advance, and after a time establish them- selves in the open country, where they seek such shelter as they can find. This transition is very slow, but there are sufficient indications, in the exceptions which are found to the general habits of the species in this particular, to show that it is going on ; and therefore it is reason- able to believe that when a period shall have elapsed as long as that since the south and west of Europe were covered with forests, our species will have become able to sustain themselves in the open country, and will have spread themselves in great numbers over those populous parts where they are now wanting. The power of adaptation to new circum- stances, which is a prominent quality of nearly all the shell-bearing species of this order, and which, combined with a remarkable tenacity of life, enables them to resist successfully the many dangers to which they are exposed, is illustrated in the extremes of their mode of life on the two
1 Tam not able to state whether the European snails are, as a class, similar in their habits to Tachea hortensis, or whether many of them may not be restricted to the forests, as ours are. i
4 TERRESTRIAL AIR-BREATHING MOLLUSKS.
continents. We know of no other instances of animals living in a natural condition, not domesticated nor accompanying man, where the same diversity of habitat in analogous species exists. The presumption of changes which shall approximate the habits of both, in proportion as the physical circumstances of both approach each other, is therefore not a violent one. But it is by no means certain that all the species will survive the violent change to which they are at first exposed. Those of. them which are in a state of decline and nearly run out, and those which are strictly local in their habitats, will be least able to sustain themselves, and their entire extinction will be very likely to follow.
All the species are nocturnal or semi-nocturnal in their habits. In the daytime they seek such shelter as may be at hand, and retreat into dark holes and crevices, or hide themselves under the fallen trunks of trees, fragments of wood, leaves, and stones, or bury themselves wholly or partially in the earth. There they remain inactive until evening twilight, when, except in seasons of drought, they sally forth in num- bers ; and in favorable situations, such as ravines and low places in the forest, may be seen crawling over the surface of the ground, and some- times climbing the stalks of plants and the trunks of trees. They are probably active during the whole night, in which time they all seek their food, and those species which are noxious to man commit their depredations in the garden and orchard. At this time, too, their sexual meetings take place. Soon after daylight they retire to their retreats, and remain very close until night approaches again. They also come forth when the atmosphere is charged with moisture, and after light showers.
There is a difference in the places of their retreat. The naked genera are oftenest found attached to the lower surface of wood and stones lying in contact with the ground, or to the damp walls of cellars, and, in the forest, concealed under logs. So soon as, from the increased dry- ness of the atmosphere, these places no longer retain moisture, they abandon them for others, and in seasons of drought they penetrate deeply into the earth. The shell-bearing genera, in the forest, are observed under prostrate timber, to the lower surface and crevices of which they adhere by a mucous attachment during the day, in hollows under, the roots of trees, and under the layer of decaying leaves which cover the ground. In situations where such places of shelter are not found, they half bury themselves in the soil, at the roots and under the shade of thick tufts of plants. Numbers frequently resort to the same
—
HABITS AND FACULTIES. 5
retreat, but this in the shell-bearing genera seems a mere matter of accident, while in the introduced species of Limaces it appears to indi- cate a gregarious habit, as they prefer to crowd together and lie in close contact with and upon each other.’ These last are said by some to occupy permanently the same retreat, but the assertion is probably incorrect. They often, and perhaps generally, remain in the immediate vicinity of the place where they procure their food, and hence they often resort to the same place of shelter; and as many of them have fre- quently been observed in the same place, they have been thought to be the same individuals. But when one set of individuals is destroyed, another soon takes their place, and whenever a new shelter is provided, by the accidental presence of fragments of wood in suitable situations, it is immediately resorted to by them. The native genus 7'ebennophorus is in no manner gregarious ; it lives in the forest, mostly buried in decaying and rotten wood, and no more than two are usually found together. In cloudy weather, when the atmosphere is charged with moisture, and during light showers, all the species come forth in the daytime ; but on a change of weather immediately return again, and during rains remain in their retreats. Long-continued or excessive rains, however, inundate their hiding-places, drive them out, and force them to resort to trees.
We have seen, in a preceding part of this work,? how numerous are the agencies which are continually tending to destroy the lives of indi- viduals, and to exterminate whole species. Being all of them slow in their motions, without means of escape from enemies, destitute of instru- ments of offence or of defence, and some of them unprovided with a cov- ering, it would seem as if their existence must be very precarious, and that they must be easy victims to the unfavorable circumstances around them. Such would be the case undoubtedly, and these causes would interfere with the diffusion of species and derange their distribution in a greater degree than they actually do, if there were not counteracting properties in the animals themselves which modify and limit the destruc- tive tendency. These conservative properties are, their prolific gener- ative capacity, their insensibility to pain, their extreme tenacity of life, and their extraordinary power of reproducing important organs which have been cut off or destroyed by accident.
1 The promiscuous mingling of individuals of Limax agrestis and Limax variegatus in their respective retreats has often reminded us of the familiar positions in which swine
place themselves for sleep. 2 See I. 182 et seg.
6 TERRESTRIAL AIR-BREATHING MOLLUSKS.
The number of eggs produced varies in the genera and species in the same proportion as the dangers to which they are exposed are greater or less. ‘Thus, in the naked genera, whose means of protection and whose chances of preservation are much less than of those protected by an external shell, the number is much greater than in the latter. The number of eggs produced by two individuals of Limax agrestis kept in confinement by Dr. Leach was, in the course of rather more than a year, seven hundred and eighty-six. It usually amounts to at least three hundred per annum. ‘The other species, though not equally prolific, multiply greatly ; and each pair of the various shell-bearing species pro- duces, annually, from thirty to one hundred eggs, and perhaps more. The young of the Zimaces complete their growth and reproduce their kind sometimes within the year of their birth, and always as soon as the second year; and the species of the other families are believed not to require a much longer time to attain maturity. This rapid increase replaces the numbers annually destroyed, and maintains the species in their relative importance.
Their extreme tenacity of life is manifested in every stage of growth, from the egg to the mature animal. The eggs of Limax have been so entirely desiccated that their form has disappeared, and there remained only a thin skin, friable between the fingers. In this condition they have been kept for years ; and yet a single hour's exposure to humidity was sufficient to restore their form and elasticity.1 They have been dried in a furnace eight successive times, until they were reduced to an almost invisible minuteness, yet in every interval have regained their original bulk in a moist situation. In all these instances the young have been developed in the same manner as in other eggs not subjected to the experiment. In the northern part of the United States we have frequently observed the eggs of the shell-bearing genera in the forest covered with snow, protected only by a single leaf, where they had remained through the winter months, constantly exposed to a tempera- ture much below the freezing-point. The shell-bearing species them- selves withstand the cold of the severest winters in the same situations ; and Succinea has been frozen in a solid block of ice, and yet escaped unharmed. Helices, when frozen in a state of confinement, though they sometimes recover so far as to move about with some activity, usually survive but a short time.
The power of reproduction of parts of the body is more astonishing
1 Bouchard-Chantereaux. 2 Leuchs.
HABITS AND FACULTIES. ‘‘f
still. It is well established by experiments on thousands of Helices, that the eye peduncles, when cut off, grow out again, — that considerable parts of the locomotive disc may be amputated, and the new parts immediately bud out, and supply their place. The great length of time they can subsist without food is another exemplification of their great tenacity of life. ‘Those species, especially, which live in dry and exposed situations have this power of endurance to a remarkable degree. A friend received specimens of Helix desertorum which had been collected in Egypt, had been shipped to Smyrna, thence to Constantinople, thence to Rio Janeiro, and finally to Boston, — occupying a period of about seven months, —- which appeared in full vigor when taken from the papers in which they had been enveloped. They were laid away in a drawer ; and on being examined three years afterwards, some of them still came out in tolerable vigor.
As stated above, the shell-bearing genera live mostly in the forest, sheltered under the trunks of fallen trees, layers of decaying leaves, stones, or in the soil itself. In these situations they pass the greater part of their lives. In the early days of spring, they sometimes assemble in considerable numbers, in warm and sunny situations, where they pass hours in indolent enjoyment of the warmth and animating influence of the sunshine. Whether these meetings serve any useful purpose in the economy of the animal, or are caused by the pleasurable sensation, and renewed strength derived from the warmth of the situation after the debility of their winter’s torpidity, is uncertain ; it is probable, however, that they precede the business of procreation. It is certain that they last but a short time, and that after early spring the animals are to be found in their usual retreats.
In the course of the months of May or June, earlier or later, accord- ing to the locality and as the season is more or less warm, they begin to lay their eggs. These are deposited, to the number of from thirty to fifty, and even more, in the moist and light mould, sheltered from the sun’s rays by leaves, or at the side of logs and stones, without any order, and slightly agglutinated together. The depth of the deposit is usually measured by the extreme length of the animal, which thrusts its head and body into the soil to the utmost extent, while the shell remains at the surface ; but sometimes the animal burrows three or four inches deep before making the deposit, in order to insure a sufficiently moist position. Three or four such deposits, and sometimes more, are made by one animal during the summer and autumn. When the deposit is
8 TERRESTRIAL AIR-BREATHING MOLLUSKS.
complete, it is abandoned by the animal. The eggs vary in size accord- ing to the magnitude of the species producing them. They are nearly globular, one axis being somewhat longer than the other, white and opaque. They consist, in general, of an external, semi-calcareous, elas- tic membrane investing the whole, the interior surface of which is usually studded with numerous rhombic, microscopic crystals of carbonate of lime, some species, however, having a hard enveloping calcareous shell, of the consistence of that of a bird’s egg ; of an inner thin, transparent, shining membrane which immediately encloses a transparent and some- what viscid fluid, analogous to the albumen of birds’ eggs; of the albu- men itself, and of the vitellus, which, possessing the same degree of transparency as the albumen, cannot be distinguished from it at this time. ‘The elastic eggs, when first laid, are often flaccid, and seemingly only half full of fluid, but they soon absorb moisture and become dis- tended. The embryo animal, with its shell, is observable in the albu- minous fluid in a few days after the egg is laid. Its exclusion takes place, under ordinary circumstances, in from twenty to thirty days, according to the state of the atmosphere. Warmth and humidity hasten the process, while cold and dryness retard it to an almost indefinite extent. The hatching of eggs laid late in the autumn is often inter- rupted by the approach of cold weather and of snow, and delayed until the next spring. In some few species the young is hatched from the egg before exclusion.
The young animal gnaws its way out of the egg, and makes its first repast of the shell which it has just left. It consists at first of about one and a half whirls, the umbilicus being minute, but open. Its growth is rapid, and it has usually increased in magnitude three or four times, before the close of the first year.
In the month of October, or at the epoch of the first frost,’ the snail ceases to feed, becomes inactive, and fixes itself to the under surface of the substance by which it is sheltered, or partially burrows in the soil, and with the aperture of the shell upward, disposes itself for its annual sleep or hibernation. Withdrawing into the shell, it forms over the aperture a membranous covering, consisting of a thin, semi-transparent mixture of lime mucus or gelatine, in some species opaque and thick, secreted from the collar of the animal. This membrang is called the
1 In Florida some species continue active during the whole winter.
2 The same process is adopted by the species of the Pacific Region to protect themselves from the effects of the dry season.
HABITS AND FACULTIES. 9
epiphragm. It is formed in this manner: The animal being withdrawn into the shell, the collar is brought to a level with the aperture, and a quantity of mucus is poured out from it and covers it. A small quan- tity of air is then emitted from the respiratory foramen, which detaches the mucus from the surface of the collar, and projects it in a convex form, like a bubble. At the same moment the animal retreats farther into the shell, leaving a vacuum between itself and the membrane, which is consequently pressed back by the external air to a level with the aperture, or even farther, so as to form a concave surface, where, having become desiccated and hard, it remains fixed. These operations are nearly simultaneous, and occupy but an instant. As the weather be- comes colder, the animal retires farther into the shell, and makes another septum, and so on, until there are sometimes as many as six of these partitions ; the circulation becomes slow ; the pulsations of the heart, which in the season of activity vary from forty to sixty in a minute, according to the temperature of the air, decrease in frequency and strength, until they at length become imperceptible ; the other func- tions of the body cease, and a state of torpidity succeeds, which is inter- rupted only by the reviving heat. of the next spring’s sun. During the months of April or May,’ on the accession of the first warm weather of the season, the animal breaks down and devours the membranous parti- tions, and comes forth to participate in the warmth and freshness of the season. At first it is weak and inactive, but, recovering in a short time its appetite, resumes its former activity. The peculiar epiphragm of Binneya is described when treating that genus.
The season of hibernation continues from four to six months. The final cause of this extraordinary condition is undoubtedly to enable the animal to resist successfully the extreme reduction of temperature, and to survive through the long period when it must, in northern climates at least, be entirely destitute of its usual food. With a view to the first purpose, a place of shelter is provided, and the aperture of the shell is hermetically sealed by the epiphragm or the hibernaculum; for the second, the state of torpor is adopted, during which the functions of digestion, respiration, and circulation being suspended, and all the secre- tions and excretions having ceased, there is no drain upon the strength and vitality of the animal, and no exhaustion of its forces. Hence it comes forth, at the end of the period, in much the same condition in which it commenced it, and resumes almost immediately its usual func-
1 In New England, earlier in more southern latitudes.
10 TERRESTRIAL AIR-BREATHING MOLLUSKS.
tions and habits. So entire is the cessation of the function of respira- tion, that the air contained between the epiphragm and the animal is found to be unchanged. ‘The circulation, however, may be partially restored by a small degree of heat, the warmth of the hand being suffi- cient to stimulate the heart to action.
The snails pass the greater part of their lives under dead leaves and logs, under stones, or burrowing in the ground. They seldom come from their lurking-places while the sun shines, and indeed are never seen ranging in the daytime unless the day be damp and dark. Should they then be surprised by the appearance of the sun, they immediately take shelter from its rays, under some cover or on the shaded side of the trunks of trees.
Their natural food is vegetable ; and the formation of the mouth and the organs with which it is armed seems to be peculiarly well adapted for cutting fruits and the succulent leaves of plants. The lower edge of the jaw being applied against the substance to be eaten, the semilunar rough instrument, which has been called the lingual membrane, is brought up against it, cutting out and carrying into the mouth semi- circular portions of nutriment. This operation is carried on with great rapidity, and the substance to be eaten soon disappears. It is certain, however, that some species? are also fond of animal food, and sometimes prey upon earthworms, their own eggs, and even upon each other ; but the slowness of their motions and their consequent inability to pursue prey forbids the idea of their being dependent on animal food. They, in their turn, become the prey of various birds and reptiles ; and it is no uncommon thing to observe, in the forest, clusters of broken shells lying on logs or stones which have been chosen by birds as con- venient places for breaking the shell and extracting the animal.
The snails of the United States are for the most part solitary in their habits, differing very much, in this respect, from the snails of Europe. It is true that in localities favorable for their residence they may be collected in considerable numbers ; and especially is this the case in the States north of the Ohio River. But even there they seem to live inde- pendently of each other, and not to unite into herds or communities. There are occasional exceptions, however, as in the case of Patula alter- nata, very large numbers of which have been observed collected into a small space, especially in winter, as if for the purpose of imparting warmth to each other. The few species of European snails which have
These are characterized by the lingual dentition. See Glandina,
HABITS AND FACULTIES. 11
been introduced retain their native habits. Z'achia hortensis, for instance, which has been transplanted to some of the small islands in the vicinity of Cape Ann, is found there in countless numbers, literally covering the soil and shrubs. It is worthy of notice, also, that each island is inhabited by a variety peculiar to itself, showing that the variety which happened to be introduced there has propagated itself, without a tendency to run into other variations. Thus, on one islet we have the yellowish-green, unicolored variety, once described as Helix subglobosa ; and on another, within a very short distance, we find a banded variety, and none others.
In regard to colors, our snails are quite plain and exceedingly uni- form ; in this respect, also, differing essentially from the species of the Old World. They vary from yellowish-green through horn-color to chest- nut, most of them being simply horn-colored. This is perhaps owing to the fact that our species do not infest our gardens and open fields, but are generally confined to forests, sheltered under logs and stones, and are rarely seen abroad except during twilight or on damp and dark days ; indeed, they almost entirely disappear as the forests are cut down, and seem to flee the approach of man. The European species, on the other hand, follow in the track of cultivation, and are common in gardens and fields, on walls and hedges, and other places exposed to the action of light. With the exception of Patula alternata and Hema- trochus varians, Liguus fasciatus, etc., there is scarcely a species having bands or variegated colors inhabiting eastern North America; and even these latter species can scarcely be regarded as an exception, as they are only to be found at the southern part of Florida, and are more properly West India shells. In Texas, and beyond the Sierra Nevada and Cascade Mountains in Oregon and California, many of the species have one or more bands.
Another peculiarity of the American snails is the toothlike appen- dages with which the aperture of a large proportion of them is armed, and which are characteristic of the group designated by Férussac under the name Helzcodonta. More than one half of the whole number, and more than three fourths of those with reflected peristome, are thus pro- vided. In some species these appendages assume the form of folds rather than teeth ; and in others we have simple threads or lamine revolving within the aperture in the course of the spire. They are not formed until the shell has attained its full growth.
The genera not furnished with an external shell are more especially nocturnal than the other families of the order, and they are so rarely
12 TERRESTRIAL AIR-BREATHING MOLLUSKS.
visible in the daytime that thousands may be near without being known. The injury which they commit in kitchen-gardens, for this reason, is often vaguely ascribed to worms or to birds ; and no measures are taken against the real culprits. Their habits, in general, coincide with those which have been described as distinguishing the order ; and we shall therefore mention here only those which are peculiar to them. They differ from the other families in not possessing the faculty of hiberna- tion, or suspension of their organic functions during the cold season, In temperate latitudes the snails hibernate, under all circumstances, on the approach of cold weather; the slugs, on the contrary, having the power of resisting extreme cold, continue in their usual haunts until severe frosts set in, when they retire into the earth and other sheltered retreats. Here they remain in a state of inaction and partial torpidity ; the functions of the body, however, still going on, though slowly and with diminished force. A slight increase of heat arouses them and stimulates their organs to renewed action, and they accordingly often come abroad in mild weather, even during the winter. Those which inhabit cellars and other protected situations are in motion throughout the year ; and individuals of all the genera and species which we have kept in confinement have continued active, fed freely, and increased in size as much in the coldest months as in the summer. All the species which have yet come under our notice possess the power of suspending themselves in the air by.a gelatinous thread. This they effect by accu- mulating a quantity of tenacious mucus at the posterior extremity of the foot, which they attach to the object from which they are to com- mence their descent ; then, loosing their own hold, they hang suspended by this point. Continuing the secretion, their own weight attenuates the mucous attachment, and draws it out into a thread. As this dries and hardens, a fresh supply is afforded, the thread is lengthened, and the animal lets itself down .any desirable distance. At this time, also, the margin of the foot pours out mucus freely, and during the whole operation the locomotive disk is in active undulatory motion, in the same manner as when in ordinary progression. It appears in this way to guide and force towards the extremity the mucus which is secreted on its surface, and which, collected at its extreme point, forms the thread. The slug often pauses in its descent, and extends its eye- peduncles and its whole body in various directions, as if seeking some object on which to make a lodgment. The faculty of suspending them-
selves in this manner indicates that they pass some part of their lives
CS ee ———————
HABITS AND FACULTIES. 13
on trees, from which they can thus make a convenient descent to the earth ; there are some species, indeed, which are stated to inhabit trees almost exclusively. It may serve also as a means by which they can suddenly escape from the attacks of their enemies, and particularly of birds. It is mostly, however, when they are young, or at least not grown to their full size, that they enjoy this power. Those which have attained their extreme dimensions and weight are too heavy to trust themselves to so frail a support. They have no power to elevate them- selves again, and in this respect are inferior to the spiders, which can both lower and raise themselves by the aid of the secreted thread. Like the spiders, however, they often remain suspended in mid-air for a time, and it is not unlikely that there is some pleasurable sensation connected with the act, which induces them thus to prolong it. We have seen the descent actually practised by every one of our Atiantic species, as well as by the large Pacific Ariolimax. Besides the watery fluid which at all times lubricates the integuments, the animals can, at their will, secrete at any point, or over the whole surface of their bodies, a more viscid and tenacious mucus than is usually exuded. This power is used as a means of defence.
Whenever a foreign substance touches them, immediately a quantity of this Limaz campestris, suspended.
mucus, of the consistence of milk and nearly of the same color, is poured out and forms a kind of membrane interposed between themselves and the irritating substance. So, also, when they are surrounded by a cor- rosive gas, or are thrown into water or alcohol, they form over them- selves in this way a thick protecting covering, which is undoubtedly a non-conductor of heat and impervious, at least for a time, to liquids. Shielded by this coating, they can live the greater part of a day im- mersed in water, and for a shorter time in alcohol; and M. Férussac asserts that they have survived for hours in boiling water. They leave a trace of their usual secretion on every object over which they pass, and thus can easily be traced to their retreats. The ordinary secretion is most abundant at their posterior extremity. The secretion of the mucous fluid over their surface is necessary to their existence. Death
14 TERRESTRIAL AIR-BREATHING MOLLUSKS.
immediately follows the failure of this power, and is preceded by the drying up of the skin. All the species are extremely voracious, and devour an incredible quantity of food in a short time. Those found in this country are generally supposed to be vegetable feeders, but nearly all of them subsist occasionally upon dead animal matter, of which they seem to be fond, and when in confinement sometimes attack and devour each other. It is probable, therefore, that in their natural condition, all of them at times resort to animal food, and devour earthworms, in- sects, and their larvee, and such other animals as, inhabiting the same retreats, are like themselves slow of motion and defenceless. It is cer- tain, however, that the principal food of those species which frequent the neighborhood of houses and gardens consists of the tender leaves of succulent plants and of ripe fruits. Upon these, in Europe, they perpe- trate serious ravages, often destroying in a night the labors and hopes of the gardener, and in some years committing so much injury, and interfering to such a degree with the prosperity of the agriculturist, that they are ranked among the scourges of the country. Like caterpillars, locusts, and rats, they are considered to be perpetual enemies, and a war of extermination is carried on against them. To limit the extent of the evil, many remedies have been proposed, and among others the prayers and exorcisms of the church have been claimed, but without any considerable abatement of it. Happily, we are not in this country subject, in the same degree, to the mischief done by these animals, for their excessive increase is kept in check, probably, by the vicissitudes of the climate ; but it may be useful to know that a border of. ashes, sand, or sawdust, laid around the bed containing the plants it is desired to protect, will prove an impassable barrier to the slugs, so long as these substances remain dry. When the slugs attempt to pass the barrier, they become entangled in the dry ashes or sand, which envelops them entirely. The particles of these adhere to the viscid surface of the ani- mals, who, in vain endeavoring to disengage themselves from them by secreting new mucus, at length become exhausted and die.
The growth of the slugs is remarkably rapid. We have known the young to double their size and weight in a week. The earliest hatched young of the season generally attain their full maturity before the end of the first year, although they may afterwards increase somewhat in bulk. Those which leave the egg at a later period mature during the second year. Individuals kept in confinement and fully fed reach a much greater size than when in their natural condition.
HABITS AND FACULTIES. 15
The slugs possess, in a remarkable degree, the power of elongation and contraction of the body. When fully extended, it is long, narrow, more or less cylindrical, and generally terminating in a sharp point. The carina of the carinated species disappears. The head is protruded far beyond the mouth ; the eye-peduncles are long, slender, and grace- ful. The mouth is changed from an oval to an elongated form, with parallel sides and rounded ends. The glands are lengthened, lose their prominence, and appear nearly smooth. But when alarmed by the touch of a foreign substance, an instant change occurs, and a sudden contraction takes place. The eye-peduncles and tentacles are retracted and the head is drawn under the mantle. The anterior edge of the mantle is brought to the level of the foot, and its form becomes nearly circular. The body is shortened to one fourth of its former length, and tumid ; the back is rounded and rises high in the centre, and the skin is rough with prominent glandular protuberances. The carina, when it exists, becomes conspicuous. This is the form which they assume in their retreats when they retire to protect themselves from the effects of drought and cold. It differs so much from their form when in motion, that one not well acquainted with them would hardly recognize
the same animal in its new shape. It is among the Limaces, perhaps,
that the change is most striking, and the difference of form between the extremes the greatest.
The slugs commence reproducing their kind as early as the end of the first year, before they have attained their full dimensions, and
‘hence the eggs of the same species often vary considerably in size.
These are deposited in a cluster of thirty, or thereabouts, in the soil and in other moist and protected situations; or if the species be one that frequents houses, then in the crevices or corners of the walls or under the decaying planks of cellars. In general form and appearance they resemble the eggs of the shell-bearing genera, but differ from them in several important particulars. The eggs of the snails are all opaque, while those of the slugs are more or less transparent, permitting, in the LIimaces, a view of the cicatricula, and affording an opportunity of ob- serving its developments. Those of the former are all deposited free, or unconnected, except by a slight agglutination ; those of the latter, in some of the species, are connected together by a prolongation of the outer membrane at their longest diameter, thus forming a sort of rosary. In other species they are deposited in a mass. The deposits of eggs, when made, are abandoned by the slug, who then removes to
16 TERRESTRIAL AIR-BREATHING MOLLUSKS.
some other convenient place. A considerable number of separate deposits are made during the year.
The slugs and some species of snails were considered by the Romans to possess medicinal properties, and this belief continued, among the nations of Europe, through the Middle Ages down to comparatively recent times. There is hardly a disease, internal or external, of man or the domestic animals, in which, according to the statements of authors, they have not proved beneficial; and the relations concerning them are numerous and truly marvellous. The testaceous rudiment of the Limax acquired in this respect a pre-eminence above the animal itself, and enjoyed a high rank among the numerous bezoars and amu- lets which were supposed to protect the body from evil influences, and to impart health and activity to its various functions. The accounts of their virtues, copied from one author to another, on the authority of names, show how easily error is perpetuated, and how difficult it is to eradicate from the public mind a false opinion which has once obtained a footing. <A full relation of all the absurdities which gained credence would form a curious page in the history of credulity and superstition. The more general diffusion of knowledge at the present day has dis- pelled these ideas in a great degree ; but some relics of them still linger among the rural population of many parts of Europe. In this country no such belief has ever prevailed ; and so hidden and clandestine are the habits of the animals, that but a small part of the population is aware of their existence, and those who are familiar with them view them with such feelings of disgust as would effectually prevent their use either as medicine or as food. They have also from very early times been used in the preparation of cosmetics; and the water pro- cured from them by distillation, no longer than two or three centuries ago, was much celebrated and used by ladies, to impart whiteness and freshness to the complexion.
Although the title of this work embraces only the terrestrial genera, I have actually included all the Geophila, and thus have been forced to treat Onchidella, whose habits are strictly marine. At the same time I have omitted several strictly terrestrial genera which are not air- breathing, but furnished with gills, such as Helicina.
1 As late as the close of the sixteenth century Helling published a dissertation with this title : ‘‘Ossiculorum limacum usus in febribus.” During the year 1863 a syrup of snails was prescribed to members of my family by two regular French physicians in Paris.
2 They are, however, frequently imported as an article of food for foreign residents of our cities.
~~ . ee @henes, S&S 7, c «
+ iJ * ‘ rw) ’ J b
GEOGRAPHICAL DISTRIBUTION. 17
II. GEOGRAPHICAL DISTRIBUTION.
I wave already in the “ Bulletin of the Museum of Comparative Zovlogy ” at Cambridge’ given as correct an idea of the distribution of our species as was possible. In repeating it here (with such additions and corrections as have been suggested by subsequent investigations), I cannot too strongly urge, in extenuation of its imperfection, the mea- greness of the data on which some of my views are founded. I may say with exact truth that California, New England, and the States north of the Ohio River are the only ones which have been thoroughly searched. The species of the rest of the country are known only by the researches of few and widely separated resident naturalists, from the collectors sent by my father, and by collections made by my correspondents while travelling in various sections of the country. The last sources of in- formation are restricted to purely accidental localities. There has been no systematic investigation of vast tracts of intervening country or of some very important points.
The subject must be studied in connection with the chapter on the same subject in Vol. I. (p. 99). I need not add that from the proper sources the student of distribution must have a thorough knowledge of the physical geography of North America.
The limits of the fauna at the South correspond quite accurately with the political limits of the United States. The Mexican fauna has lately been investigated by Messrs. Fischer and Crosse in the exhaustive work on “Les Mollusques Terrestres et Fluviatiles du Mexique et de Amérique Centrale.” The northern limit of the fauna is formed by climate alone. Thus our limits comprise all the continent of North America, from the extreme north to San Diego and the Rio Grande.
Properly speaking, there are two distinct faunas within these limits, the Pacific and Eastern, with perhaps a third in the Central Basin, but for convenience they are all treated as part of the North American fauna. I have therefore designated these as
J. Tae Paciric PRovInce. II. THe Centrau PROVINCE. III. Tue Eastern Province.”
1 Vol. IIT, No. 9. 1873. 2 In the work of Wallace quoted below, North America is designated as the Nearctic Region. The subdivisions proposed by him correspond almost exactly with my own
18 TERRESTRIAL AIR-BREATHING MOLLUSKS.
The boundaries of these provinces and the subdivisions which appear to exist in them will be given below, as well as lists of their peculiar species. It must be distinctly understood, however, that future re- searches, especially at the South and Southwest, may greatly modify the views here presented.
I. Tue Paciric Province’ comprises a narrow strip between the Sierra Nevada and Cascade Mountains on the east, and the Pacific Ocean on the west. Its southern limit is San Diego, from whence it extends northerly into Alaska.
Over the whole of this province the following species range : —
Macrocyclis Vancouverensis. Ariolimax Columbianus. sportella. Prophysaon Hemphilli. Mesodon Columbiana. Succinea rusticana. germana. Oregonensis, Arionta tudiculata. Nuttalliana.
Over the whole of this province we find also the following species com- mon to Eastern North America. They also extend over the whole north- ern portion of the continent, where the mountains by their lower altitude are not barriers to distribution. It is, no doubt, from these regions that they have spread through the Pacific Province, and not westward over the Rocky Mountains. Had other Eastern species extended over the boreal regions, we should, no doubt, have found them also spreading into the Pacific States. They are especially found along the Sierra
Nevada.
Zonites arboreus. Limax campestris ? indentatus. Patula striatella. minusculus. Helicodiscus lineatus. milium. Punctum minutissimum.
In the Pacific Province we also find several species common to the circumpolar regions of Asia, Europe, and America. They have like- wise spread southward along the Sierra Nevada and on either side of it,
Thus his Californian and Rocky Mountain Sub-Region are identical with my Pacific and Central Provinces. His Canadian Sub-Region is about the same as my Northern Re- gion of the Eastern Provinee. His Alleghany Sub-Region includes both my Interior and Southern Region of the Eastern Province,
1 A most interesting account of this fauna is given by Dr. J. G. Cooper: ‘On the Distribution and Localities of West Coast Helicoid Land Shells” (Am. Journ. of Conch.
TI. p. 211, with a map),
GEOGRAPHICAL DISTRIBUTION. 19
They have also spread southward over the Central and Eastern Proy- inces, and now inhabit most, if not all, of North America. They are
Zonites fulvus. Ferussacia subcylindrica.
Other species will probably be added to this list by further search ; among them Vallonia pulchella.
In dealing with the species from the North in Eastern North Amer- ica (see below, p. 27), the question of their distribution will be more fully discussed.
In addition to the species already enumerated as common to the whole Pacific Province, there are many more restricted in their range. It appears that the Pacific Province is divided into two regions, (a) the Oregonian and () Californian, the two intermingling slightly or over- lapping in the extreme north of California, near Humboldt Bay. The faunas of these regions are nearly allied.
(a) The Oregon Region lies between the Cascade Mountains and the Pacific Ocean, extending northerly through British Columbia into Alaska.
The following species are peculiar to it :'—
Zonites Stearnsi. Arionta Townsendiana, ‘Microphysa Lansingi. Arion foliolatus ? Mesodon devia. Hemphillia glandulosa, Aglaja fidelis. Succinea Hawkinsi.
There seems to be here some overlapping of the Pacific and Central Provinces, as Arionta Townsendiana, Mesodon devia, and Macrocyclis Vancouverensis extend along the mountains southeasterly into Idaho and Montana. The former two become much dwarfed in size at their most eastern range. 7
(o.) The Californian Region extends from Humboldt Bay to: San Diego, between the Sierra Navada and Cascade Mountains on the east, and the Pacific Ocean on the west.
The following are the species peculiar to it : —
Macrocyclis Voyana. Zonites chersinellus. Duranti. Limax Hewstoni. Vitrina Pfeifferi. Binneya notabilis. Zonites Whitneyi. Ariolimax Californicus. conspectus. niger.
1 TI formerly omitted Onchidella borealis, Dall, from Sitka, being doubtful whether the genus should be treated as American, More recently I have had reason to include it in my work ; see below.
20 TERRESTRIAL AIR-BREATHING MOLLUSKS.
Ariolimax Hemphilli. Arionta Carpenteri. Andersoni. Mormonum.
Arion? Andersoni. sequoicola.
Gonostoma Yatesi. Traski.
Triodopsis Harfordiana. Dupetithouarsi.
loricata. ruficincta.
Aglaja infumata. Gabbi.
Hillebrandi. facta.
Arionta arrosa. Kelletti. Nickliniana. Stearnsiana. Ayresiana. Euparypha Tryoni. redimita. Glyptostoma Newberryanum. intercisa. Pupa corpulenta. exarata. Rowelli. ramentosa. Californica. Californiensis. Succinea Sillimani. Diabloensis. Stretchiana.
Of the above, several species extend beyond the limits of the region. Thus, Vitrina Pfeifferi, Zonites Whitneyi, Pupa corpulenta, Succinea Sillimani, Succinea Stretchiana, and S. rusticana are found also on the western slope of the Sierra Nevada in the Central Province. Aglaja infumata and Macrocyclis Voyana are also found outside the bounds of the Region, in the Oregonian Region.
With the fauna of Lower California there seems no connection, though one or two species overlap at the dividing line, as Arionta Stearnsiana. Another species, A. Carpentert, is included in the above list, having been quoted from San Diego and Tulare Valley, California. It may, however, belong rather to the Lower California fauna,* having been
* The peninsula of Lower California forms a distinct molluscous province of itself, ex-
tending nearly to San Diego, The following species are peculiar to it : —
Ccelocentrum irregulare, Gabb. Bulimulus pallidior, Sowerby. Arionta Stearnsiana, Newc. excelsus, Gould. Rowelli, Newce. (Lohri, Gabb.) inscendens, W. G. Binn. EBuparypha areolata, Sowb. ( Veitchii. sufflatus, Gould. Tryon). pilula, W. G. Binn. Pandore, Forbes. proteus, Brod. levis, P/r. Xantusi, W. G. Binn. Berendtia Taylori, P/. artemisia, W. G. Binn. Bulimus spirifer, Gubb. Onchidium Carpenteri, W. G. Binn.
Gabbi, Crosse.
Veronicella olivacea, Stearns, a Nicaraguan species, is also found in Lower California. Of the above list one only has been found near San Diego, A. Stearnsiana. Another, A. Rowelli, has been referred to Arizona, but with doubtful accuracy. 2. Pandore and are- olata have also erroneously been referred to California. A. Remondi (Carpenter?) is omitted from the list, as it also occurs in the California Region. It is the only species
ee an"? Wo Se gglle
GEOGRAPHICAL DISTRIBUTION. 21
described from that region under the name of H/. Remondi, and from Guaymas. Veronzcella olivacea, Stearns, a Nicaraguan species, is also said to extend into California. I should also mention that Binneya notabilis has been found on Guadalupe Island, off the coast of Lower California.
From the list of California species are omitted Columna Californica, actually collected at Marmato, New Granada, by Mr. Bland, and Zonztes cultellatus, probably an accidentally introduced European shell. Buli- mus Californicus is also omitted, belonging, no doubt, to the region of Mazatlan. Also Glandina Alberst, which we know to live in the Sierra Madre.
Separate lists of species peculiar to the several regions of the Pacific Province are given above. There now follows a complete list of all the species hitherto observed in the entire Province.
Macrocyclis Vancouverensis. Vitrina Pfeifferi. sportella. Limax campestris. Voyana. Hewstoni. Duranti. Prophysaon Hempbhilli. Zonites Whitneyi. Ariolimax Columbianus. arboreus. Californicus. indentatus. niger. minusculus, Hemphilli. milium. Andersoni. conspectus. Arion? foliolatus. chersinellus. ? Andersoni. Stearnsi. Binneya notabilis. fulvus. Hemphillia glandulosa.
common to the peninsula and mainland of Mexico. The most interesting fact in the fauna
_of Lower California is the presence of Bulimulus proteus and B. pallidior, — species de-
scribed originally from South America, the former from Chili. Such facts can only be accounted for by a theory of former connection of the two points.
Though still more remotely connected with the subject of this paper, it will be inter- esting to add here a list of species found at and north of Mazatlan, on the Pacific coast of Mexico.
Glandina turris, Pfr. Polygyra acutedentata, W. G. Binn. Albersi, P/*. ventrosula, P/. Holospira Remondi, Gabb. Bulimulus Ziegleri, P/r. Patula Mazatlanica, P/*. Californicus, Rve. ? Arionta Carpenteri, Newc, Orthalicus undatus, Brug. Polygyra anilis, Gabb. Pupa chordata, P/r. Behri, Gabb. Succinea cingulata, Forbes.
Of the above, P. Mazatlanica has lately been quoted from San Francisco, confounded with some allied species, as I have since learned.
A. Mormonum is omitted frorh this list, its presence in Sonora not having been con- firmed, although asserted, doubtfully, by Messrs. Fischer and Crosse.
22 TERRESTRIAL AIR-BREATHING MOLLUSKS.
Patula striatella.
Arionta sequoicola.
Microphysa Lansingi. Diabloensis. Helicodiscus lineatus. Traski. Gonostoma Yatesi. Dupetithouarsi. Triodopsis Harfordiana. ruficincta. loricata. facta. Mesodon Columbiana. Gabbi. germana. Kelletti. devia. Stearnsiana. Aglaja fidelis. Euparypha Tryoni. infumata. Glyptostoma Newberryanum. Hillebrandi. Ferussacia subcylindrica. Arionta arrosa. Pupa Rowelli. Townsendiana. Californica. tudiculata. corpulenta. Nickliniana. Succinea Sillimani. Ayresiana. Stretchiana. redimita. Hawkinsi. intercisa. rusticana. exarata. Nuttalliana. ramentosa. Oregonensis. Californiensis. Punctum minutissimum. Carpenteri. Veronicella olivacea. Mormonum.
Several of the above will eventually prove to be synonymes, but the total number of species is small in comparison with the great size of the Pacific Province. An equal extent of territory in the Mississippi Valley, or even on the Atlantic coast, would show a larger number ; and the comparatively small regions of Texas, Florida, and the Cumberland Mountains would each show an equal number of species peculiar to itself, independent of what they have in common with the rest of East- ern North America. This disparity in number is still more plainly shown in the separate region of Oregon. Thus it appears that the Pacific Province is not rich in the number of its species, but it is peculiarly favored in their size and beauty, — in this respect strikingly in contrast with the Central Province and Eastern Province.
From the Central Province the Pacific Province is quite distinct. A few species have been shown above to inhabit both slopes of the Sierra Nevada, and a few of the Oregon species have passed the barrier of the Cascade Mountains on the north,’ but the peculiar Pacific forms, such as Arionta and Aglaia, are unknown in the Central Province. On the
1 Since the above was published I have received living specimens of Patula solitaria from the Dalles on the Columbia River, proving that thf species has passed the barrier of the Cascade Mountains and penetrated into the Pacific Region. It had already been noticed in the Central Province.
GEOGRAPHICAL DISTRIBUTION. 23
other hand, the only form which has any development in the Central Province, Patula, is scarcely known in the Pacific Province.
Compared with Eastern North America, or the Eastern Province, as it is designated below, the Pacific Province is remarkable for the absence of all the larger Zonztes. The presence of the smaller species, also, may perhaps be accounted for by migration from the north, so that the genus Zonites cannot be considered as characteristic of the Province. The genus Pupa is less common. The genera Z'ebennophorus and Pallifera, so universally distributed in Eastern North America, are unknown, and so are the southern genera Glandina and Bulimulus. On the other hand, we find the genus Macrocyclis much more developed, and meet several genera unknown in the Eastern Province, such as Ariolimaz, Binneya, Prophysaon, and Hemphillia. The genera of disintegrated Helix are proportionally more developed in the Pacific Region, and are represented by quite dissimilar subgenera. The genera so peculiar to the Eastern Province, Polygyra, Stenotrema, Triodopsis, Mesodon, are scarcely represented. In their place we find Aglaza and Arionta, forms unknown in the Eastern Province. The latter, though feebly repre- sented in Europe, is characteristic of California. It is prolific of species and also of varieties to a degree which has caused some confusion in the synonymy. Glyptostoma is also peculiar to California.
From Lower California and Mexico the Pacific Region has been shown to be equally distinct, wanting entirely the Holospira, Glandina, Buli- mulus, and Zonites of those regions.
Failing on the north, east, and south, the west alone is left to us from whence to trace the pulmonate fauna of the Pacific Region, and here the secret of its origin lies buried under the Pacific Ocean.*
fF 1 A subsidence of eight hundred feet in the continent of North America would leave on its eastern shore a strip of land of about equal size of our Pacific Region, equally distinct in its terrestrial mollusca from the balance of the continent. In this case, however, we should have a distant island of the Appalachian chain on which we should find all the species of the eastern coast of the mainland. This would give us a proof of what we can now only suspect as regards the Pacific Province, —of former more wide distribution of its pulmonate fauna. From wherever the fauna may have originated, we can easily explain its present condition. The physical and climatic features of the Pacific Region are such as readily to account for its richness in terrestrial mollusks in comparison with the less favored Central Province, and even with the Eastern Province. In the supposed subsi- dence in the Southern Region the change would be still greater. All the species peculiar to it, catalogued on p. 35, would perish, excepting Bulimulus dealbatus. This species would still be found in Kentucky, restricted to a small area ; all record of its former wide distribution being at the same time destroyed.
_ The West Indian and South American species, catalogued on pp. 36, 37, would no longer
24 TERRESTRIAL AIR-BREATHING MOLLUSKS.
II. Tae Cenrrat Province extends from Mexico to the British Possessions, between the Rocky Mountains on the east, and the Sierra Nevada and Cascade Mountains on the west.
The following are the species peculiar to the province : —
Limax montanus. Patula Horni.
Patula strigosa. Microphysa Ingersolli. Cooperi. Polygyrella polygyrella. Haydeni. Mesodon Mullani (=devia). Idahoensis. Pupa Arizonensis. Hemphilli. hordeacea.,
The second and third of these species, perhaps identical, are also found on the eastern slope of the Rocky Mountains, in Wyoming and Dakota, in company with P. solitaria. I have shown above that the last-named species has penetrated the Central Province, and even passed the barriers of the Pacific Province at the Dalles.
To the above must be added, as inhabiting the province, but not peculiar to it, the following species from the Pacific Province, inhabiting either slope of the Sierra Nevada: Vitrina Pfeifferi, Zonites Whitneyt, Pupa corpulenta, Succinea Sillimani, and Suceinea Stretchiana. The fol- lowing, also, from the Oregonian Region of the Pacific Province, Mesodon devia, Arionta Townsendiana, and Macrocyclis Vancouverensis, are found at its most northern point, though the former two species are reduced in size.
be found on the North American Continent, nor would any record be preserved of the former connection of the regions. Indeed, no one would then suspect that the tropical genera Glandina, Veronicella, and Cylindrella had ever been represented on the eastern portion of this continent.
The West India Islands being much more widely separated from North America, the presence among them of the small American species (catalogued on p. 37) would be still more difficult to explain.
Again, the supposed subsidence would destroy most of the species peculiar to the Sub- Region of Texas (see p. 37), and remove the evidence of the present intermingling of the North American and Mexican faunas in that Sub-Region.
Another effect would be to remove from our reach all evidence of the origin of our species in Post-pleiocene days, the fossil deposits in the bluffs being rendered inaccessible. Thus one would not be able to have correct impressions of the origin and distribution of certain species. The non-pulmonate Helicine give the best instance of this. Finding Helicina orbiculata and occulta confined to the narrow limits of the Appalachian Island, one would have no reason to suspect their past history has been so much more interesting than that of many of the species of Stenotrema, ete., found with them, which never had had a larger distribution. It would be impossible to know that Helicina orbiculata and occulta flourished greatly in Post-pleiocene times ; that later, one of them, occulta, became comparatively rare and restricted in range, while orbiculata became very numerous in
GEOGRAPHICAL DISTRIBUTION. 25
We find, also, over the Central Province the following species, whose derivation can readily be traced to the north ;! Zonites minusculus, ful- vus, indentatus, Vallonia pulchella, Helicodiscus lineatus, Patula striatella, Ferussacia subcylindrica.
Arionta Rowelli, a Lower California species, is omitted from the list, its presence in Arizona not being well authenticated.
The fauna of the Central Province is quite distinct from that of the Pacific Province, but is nearly allied to that of the Eastern Province, its genera being the same, excepting Polygyrella. It may therefore be of the same origin as the fauna of the Eastern Province.
The paucity of species over this large province is owing to the nature of its climate and soil, — causes in equal force on the western border of the Eastern Province.
In order to avoid mistakes in the study of the geographical distribution of North American Land Shells, one must constantly bear in mind the
.
individuals over a vast extent of territory ; and finally, that our supposed subsidence gradually restricted them to the Appalachian Island.
This supposition of subsidence might be carried still further, till we should have in cer- tain islands of the Appalachian chain the sole resting-places of the now widely distributed Eastern North American fauna. The more southern of these islands would alone retain the species of the present Cumberland Sub-Region, and thus be much richer in species than the more northern islands, On the other hand, these more northern islands would possess species derived from the present northern regions which would not be found in the southern islands.
Still more instructive is the supposition of a subsidence in Eastern North America which would leave above the level of the sea only two groups of islands, formed by the White Mountains of New Hampshire, and Mount Mitchell and Black Mountain of North Carolina. On the latter we may suppose would be preserved all the species given in the lists on pp. 32, 33. Of these species all would be peculiar to the island, except such as are named in the list on p. 30, which would all be found also in the White Mountains, where we should also find the following species peculiar to the islands, Mesodon Sayii, dentifera; Vitrina limpida; Zonites milium, Binneyanus, ferreus, exiguus, multidentatus; Patula striatella, asteriscus; Pupa decora; Vertigo Gouldi, Bollesiana, simplex; Succinea Totteniana. Of the former distribution of these species nothing could be known, but a former connection of the two groups of islands would be surely indicated by the presence of so large a proportion of species common to each. A former connection of the two groups of islands with Europe and Asia would be as surely indicated by the presence on each of Zonites fulvus, nitidus, viridulus; Acanthinula harpa,; Vallonia pulchellu ; Lerussacia subcylindrica, and Pupa muscorum. Nor could it escape the attention of conchologists that these and other small species, Z. arboreus, etc. (see p. 27, note), proved that a former connection must have existed between these groups of islands and the far-off Central and Pacific Provinces.
1 See remarks on the distribution of these species over Eastern North America, below. i¢
26 TERRESTRIAL AIR-BREATHING MOLLUSKS. —
changes in the names and boundaries of the trans-Mississippi States and Territories.*
III. THe Eastern Province comprises the remaining portions of the continent north of Mexico. The species by which it is inhabited have been derived partly from the north, partly from the interior, and partly from the south. It may therefore be divided into the (a) Northern Region, (>) the Interior Region, and (c) the Southern Region.
(a.) The Northern Region? comprises the whole northern portion of the continent, including Greenland and Alaska. Its southern boun- _ dary is not perfectly known, and probably not exactly marked ; it may, however, be indicated in general terms as the same with the political division between the British Possessions and the United States to the northeast corner of New York, where it runs southwesterly along the Appalachian chain of mountains to Chesapeake Bay, thus including all New England, and the portions of New York, New Jersey, Penn- sylvania, and Maryland lying east of those mountains. Into this south- ern extension of the Region we find the Interior Region overlapping, as will be shown below while treating of the Interior fauna. At other points in the Region, also, have been found species from the Interior Region,® especially small Zonites, which are able to bear the severe climate of the north.
The following are the species of the Northern Region : —
Vitrina limpida. Zonites multidentatus. Angelice. Patula striatella. exilis. asteriscus.
Zonites fulvus. pauper. nitidus. Acanthinula harpa. viridulus. Vallonia pulchella. Fabricii. Ferussacia subcylindrica. milium. Pupa muscorum. Binneyanus. Blandi. ferreus. Hoppii. exiguus. decora.
1 Thus, Helix Mullani was described in Land and Freshwater Shells of North America, I. 131, from points in Washington Territory and Oregon. Both localities are now in Idaho. (1875.)
2 For a description of this Region, see Vol. I. pp. 124, 125, under sections 5 and 6. The American land shells, especially those of the Interior Region, are forest species ; they become rare towards the Northern Region of the continent as the deciduous trees become rare. bats
8 See Proc. Phila. Acad. N. S., 1861, p. 330, for the northern_range of species from the Interior Region.
ENS Ries ho
aa
GEOGRAPHICAL DISTRIBUTION. 27 Pupa borealis. Succinea Haydeni. Vertigo Gouldi. Verrilli. Bollesiana. Higginsi. simplex. Groenlandica. Punctum minutissimum. Totteniana.
Of the above, several are circumpolar species, common to the three continents of Europe, Asia, and America. There being no mountain- barriers in these regions, they are not restricted in their range across America. In their progress southward, also, they have met with no transverse mountain-barriers, but have spread equally on the east and west of the Rocky Mountains and Sierra Nevada. Hence we find them common to the whole of North America. Such are : —
Zonites viridulus. Vallonia pulchella. fulvus. Ferussacia subcylindrica. nitidus. Pupa muscorum.
Acanthinula harpa.
This list will be increased should it be proved that Mr. Gwyn Jef- freys? is correct in referring the following American species to those of Europe: Vitrina limpida=V. pellucida, Punctum minutissimum = Helix pygmeea, Drap., Limax campestris—= LL. levis, Mill., Vertigo Gouldii=V. alpestris, Ald., Vertigo Bollesiana—= V. pygmza, Drap., V. ovata=V. antivergo, Drap., V. ventricosa—=V. Moulinsiana, V. simplex = VY. edentula, Drap., Succinea ovalis—=S. elegans, Risso, S, Totteniana=S. putris, Drap. var. A comparison of the lingual denti- tion of many of these has convinced me that Mr. Gwyn Jeffreys is not correct, as shown below in the descriptive portion of my work, under each species of the list.
From Asia have come into Alaska the following : Vitrina exilis, Patula pauper, Pupa borealis.
1 In the same way we can account for the distribution of the small eastern species over the Central and Pacific Provinces, They have not crossed the mountain-barriers, but spread southward from their wider range in the north. Such are :—
Zonites arboreus. Limax campestris. indentatus. Patula striatella. minusculus. Helicodiscus lineatus. milium. Punctum minutissimum.
These northern species, both indigenous and circumpolar, may have been assisted in their migration southward by glacial agencies. There is a wide field for speculation here.
2 Ann. and Mag. N. H., 1872, 245, 246.
28 TERRESTRIAL AIR-BREATHING MOLLUSKS.
The species peculiar to Greenland are Vitrina Angelice, Zonites Fabricii, Pupa Hoppii, and Succinea Groenlandica. Of these, Pupa Hoppii has, however, also been found on Anticosti Island.
Into this Northern Region have also been introduced by commerce from Europe the following: Zonites cellarius, at most of, if not at all of, the ports from New York to Halifax; Limax flavus, L. agrestis, and Arion fuscus, which follow the white man over the whole United States, living around his habitations; and Z. maximus, also around human habitations, but noticed only in Newport, R. I., New York City, and Philadelphia; Fruticicola hispida at Halifax, F. rufescens at Quebec; Tachea hortensis on the islands off the coast of New England and the British Provinces, and on the mainland in Canada and Greenland.
Of the species referred above to the Northern Region, several have spread beyond its limits. Vitrina mpida has been found in Central New York; Zonites viridulus extends to Mexico; Z. milium to San Francisco and Kentucky ; Z. fudvus and Vallonia pulchella all over the United States; Zonites netidus, Z. multidentatus, and Punctum minutis- stmum to Ohio, the last to Texas and to California; Ferussacia subcylin- drica to the States south of the Great Lakes and into California and New Mexico ; Patula striatella to Virginia, as well as into Oregon and Nevada. .
The Northern Region does not differ in the characteristics of its fauna from that lying south of it, but its climate is too severe for any but the more hardy forms. Thus, we find only the small species of Zonztes and disintegrated Helix, with the genus Vitrina. Compared with the bal- ance of North America, the Region is peculiar for the great distribution of its species east and west, owing to the mountain-ranges having here lost the great elevation which they have farther south, and thus ceasing to be barriers to distribution. The Region is also interesting as being the source from whence have spread southward over the whole conti- nent several small species now found in Florida and Texas, and even in Mexico and the West Indies.
(®.) The Interior Region lies to the south of the Northern Region, but extends only as far as the Rocky Mountains! on the west. South- erly it extends to the alluvial regions of the Atlantic and Gulf coasts, the dividing line here not being sharply defined.
This is the only portion of the continent where we have evidence of
1 This is the extreme limit, but before reaching it the land shells have become very rare, owing to the nature of the soil. For a description see Vol. I. 1. c.
a |
GEOGRAPHICAL DISTRIBUTION. 29
the origin of our land mollusks in former geological times. In the Post-pleiocene deposits along the Ohio and Mississippi Rivers are found immense beds of shells, “ proving that our existing species were living at a period which, though recent in a geological sense, was anterior to the last geological revolution, when the surface of this portion of the earth was brought to its present condition, and to the existence of the higher order of animals which now inhabit it, and even to that of the extinct mammalians which are known only by their gigantic remains.”?
From the evidence gathered from these deposits, it appears that the fauna of this Region can be traced to Indiana and Ohio. From this centre the species have extended over the Region ; some of them also have passed the barrier of the Appalachian chain into the Northern Region, and some have spread, with the enlargement of the continent, into the Southern Region. Another theory might suggest that the Cumberland Sub-Region was the point of origin of all the species, those still restricted to that sub-region not being adapted to the wider distri- bution which the other species have obtained. Any one familiar with the habits of snails is well aware how much they differ in this respect. Some are much more disposed to migrate than others. Thus, Z’riodopsis appressa is content to remain within a radius of a few feet under a decaying log; Mesodon thyroides is more restless, travels much, and climbs trees; Zachea nemoralis has no local attachments, migrating far and wide. These facts I have verified in my own garden during many years. The Z'riodopsis appressa spoken of are descendants of Illinois specimens given me twenty years ago by the lamented Kennicott.
I will here mention that a colony of 7. appressa has lately been found in the island of Bermuda, no doubt introduced on plants.
The following species have actually been found fossil in the Post- pleiocene deposits : —
Zonites arboreus. Macrocyclis concava. fuliginosus. Patula solitaria. inornatus. alternata. intertextus. perspectiva. ligerus. Helicodiscus lineatus. gularis. Strobila labyrinthica.
1 See Vol. I. 185, It must be remembered that the glacial epoch would not destroy this fauna, as the ice sheet did not extend over the southern portion of the Region. Here the species would be preserved, and from hence, after the disappearance of the ice, they would repeople the whole Region.
30 TERRESTRIAL AIR-BREATHING MOLLUSKS. Polygyra auriformis. _ Mesodon exoleta. Stenotrema stenotremum. thyroides. hirsutum. clausa. monodon. profunda. Triodopsis palliata. Pupa armifera. obstricta. contracta. appressa. Succinea obliqua. inflecta. Helicina! orbiculata. Mesodon albolabris. occulta. elevata.
Of the above all are now living and are equally numerous, excepting Helicina occulta, a species most abundant in Post-pleiocene days, but now almost extinct.? The other species of Helicina is now confined to more southern limits.
In addition to the above, the following species, now living in the Inte- rior Province, probably had their origin in Post-pleiocene times and will, no doubt, be found fossil in the “bluffs” : —
Zonites friabilis. Mesodon bucculenta. levigatus. Sayii. suppressus. Triodopsis tridentata. indentatus. fallax. internus. Pupa pentodon. minusculus. fallax. limatulus. rupicola.
Polygyra Dorfeuilliana. corticaria.
leporina. Vertigo milium.
Mesodon multilineata. ovata.
Pennsylvanica. Succinea avara Mitchelliana. ovalis. dentifera.
Tebennophorus Caroliniensis, Pallifera dorsalis, and Limax campestris probably have also come down from Post-pleiocene times. From their nature they could leave no record of their presence in the “ bluffs.”
There are also found in the Interior Region several forms of Succinea of doubtful specific value, which have been described as
Succinea retusa. Succinea aurea. Grosvenori. Mooresiana. lineata.
The following is a complete list of those species of the Interior Region
1 Though not Pulmonata, these two species are strictly terrestrial in their habits, and are here introduced from their value on the question of the permanence of the Post-pleio- cene species. One of them is almost extinct, the other more restricted in its range at present.
2 See Vol. I. 188, 184; Bland and Binney, Ann. Lyc. N. H. of N. Y., TX, 289.
ae
GEOGRAPHICAL DISTRIBUTION. 31
which have spread beyond it by passing the barriers of the Appalachian chain, and are now found over New England and the whole southern extension of the Northern Region, described on p. 26, as well as over the whole Southern Region. They may therefore be said to inhabit all of the Kastern Province.
Macrocyclis concava. Triodopsis fallax. Zonites fuliginosus. Mesodon albolabris. inornatus. thyroides suppressus. Pupa pentodon. indentatus. fallax. arboreus, armifera. minusculus. contracta. Limax campestris. rupicola. Patula alternata. corticaria. Helicodiscus lineatus. Vertigo milium. Strobila labyrinthica. ovata. Stenotrema hirsutum. Succinea avara. monodon. obliqua. Triodopsis palliata. | Tebennophorus Caroliniensis. tridentata. Pallifera dorsalis,
Mesodon Sayu and M. dentifera have spread into New England only from the Interior Region. They have not been found in more southern latitudes on the Atlantic slopes of the Appalachian chain, nor in the Southern Region.
The geographical range of these species is very great, forming one of the most striking features of the North American fauna. Still more widely distributed are those minute species which have been mentioned above as spreading southwardly from the Northern Region equally on both sides of the Sierra Nevada and Rocky Mountains. These species may be said to inhabit the whole continent of North America as far south as Mexico. The range of some is still greater. Thus, Zonites minusculus has been found from British Columbia to Labrador on the north, to Yucatan and Florida on the south, and still farther in Cuba, Jamaica, Porto Rico, and Bermuda. Strobila labyrinthica also is found over all Eastern North America, and perhaps in Mexico (as H. Strebeli, see Fischer and Crosse, Moll. Mex. et Guat., 267). It is also by some considered identical with an Eocene fossil of France and England. (See below.) Zonites arboreus ranges from Labrador to New Mexico, and in Nevada and California, and from British Columbia to Florida, Cuba, and Guadaloupe. Vertigo ovata is found from Maine to Mexico and in Cuba.
The character of the soil and climate, with, perhaps, the gradual ele- vation, is such as to render the land shells rare, if not quite extinct,
32 TERRESTRIAL AIR-BREATHING MOLLUSKS.
before the Rocky Mountains are reached, the western boundary of the Interior Region. But one species, Patula solitaria, seems to have passed this mountain-barrier into the Central Province. This is found with P. Coopert in Montana and Idaho, very difficult to distinguish from forms of the last species. It is, however, oviparous (from Salmon River, Idaho), while P. strigosa, Coopert, Hemphilli, and Idahoensis are viviparous.! It has also passed into the Pacific Province at the Dalles.
The following list contains the names of all the species inhabiting the Interior Region, including those which have spread into it from the
Northern Region : —
Macrocyclis concava. Zonites fuliginosus.
friabilis. multilineata. levigatus. Pennsylvanica. ligerus. Mitchelliana. | intertextus. elevata. inornatus. exoleta. nitidus. dentifera. arboreus. thyroides. viridulus. clausa. indentatus. profunda. limatulus. Sayii. minusculus. Acanthinula harpa. fulvus. Vallonia pulchella. gularis. Pupa muscorum. suppressus. pentodon. internus. fallax.
Limax campestris. armifera.
Patula solitaria. contracta. alternata. rupicola. perspectiva. corticaria. striatella. Vertigo milium.
Helicodiscus lineatus. ovata.
Strobila labyrinthica. Succinea retusa.
Polygyra Dorfeuilliana. — Grosvenori.
leporina. Mooresiana. auriformis. ovalis.
Stenotrema stenotremum. lineata.
hirsutum. avara. monodon. aurea.
Triodopsis palliata. obliqua.
obstricta. Totteniana. appressa. Tebennophorus Caroliniensis. inflecta. Pallifera dorsalis.
tridentata.
1 It has been suggested by Dr. H. Dohrn that this characteristic is connected with the fact of the great dryness of the soil in the Central Province. The young shell is ready to
Triodopsis fallax. Mesodon albolabris.
GEOGRAPHICAL DISTRIBUTION. 33
The above list shows the Interior Region to be remarkable for the development of the section of Zonites familiar by the European Z. olv- vetorum (Mesomphia of Alb. ed, 2). Of the disintegrated genus Helix the section or genus Mesodon is most developed. This is almost exclu- sively a North American subgenus, as is also Z’riodopsis, which is also greatly developed in the Interior Region.
In addition to the species included in the above list as inhabiting all of the Interior Region, there is a large group of species found within its limits, but having a more restricted range. They are found in what may be called the Cumberland Sub-Region. This is comprised in the southern portion of the Appalachian chain, situated in Eastern Tennes- see and the adjoining counties of North Carolina, with an offshoot into the mountains of West Virginia.’
The following species are peculiar to this Sub-Region : —
Vitrina latissima. Stenotrema labrosum. Zonites capnodes. Edgarianum. subplanus. Edvardsi. sculptilis. barbigerum. Elliotti. maxillatum. demissus. Triodopsis Rugeli. capsella. introferens. placentula. Mesodon Clarki. lasmodon. Christyi. Patula Cumberlandiana. Lawi. tenuistriata? Wheatleyi. Polygyra fastigans. Wetherbyi. Troostiana. Downieana. Hazardi. Pallifera Wetherbyi.
Stenotrema spinosum.
Of these, several have spread beyond the limits given above for the Sub-Region. Thus, Zonites lasmodon and Stenotrema spinosum have been found in Northern Alabama. Polygyra Hazard: has also spread into Northern Alabama, and equally into Georgia and Kentucky. Steno- trema labrosum and Ldgarianum in Alabama, and in one case have been collected in Arkansas. 8S. barbigerum, S. maxillatum, and Zonites cap- nodes have found their way into Alabama and Georgia; Mesodon Clarki into Georgia. Zonites subplanus has been found even in Pennsylvania,
protect itself from the moment of its birth, while, if deposited as an egg by the parent, it might perish from drought.
1 For a description of its physical and climatic characters, see Vol. I. 122. It is there designated as the Southern Interior Section, and is given a wider western range.
34 TERRESTRIAL AIR-BREATHING MOLLUSKS.
having, no doubt, crept along the mountain chain ; but no other of the species of the Cumberland Sub-Region has been found as far north, excepting Z. demissus. This last-named species is found in a highly developed state in Eastern Tennessee, and has extended into Western Pennsylvania, North Carolina, Georgia, Alabama (near Mahila) and Arkansas in a much dwarfed condition.
If to the twenty-nine species catalogued above as peculiar to the Sub-Region are added the sixty-six species which inhabit it as a portion of the Interior Region (see p. 32), it will be seen that in the Cumber- land Sub-Region we find the largest number of species of any portion of North America. The Sub-Region is equally prolific in individuals, and the individuals are highly developed. These facts are partially explained by the nature of the country. Low mountains, thickly shaded, well-watered, and with a genial climate and proper soil, offer in their thickets and ravines innumerable saf¢ breeding-grounds for the land shells.1| There seem also to be in this Sub-Region conditions peculiarly conducive to testaceous variation. Six (or twenty per cent) of its peculiar species are carinated, and here also the following spe- cies of the Interior Region show the same tendency to carination, — Zonites ligerus, intertextus, Patula alternata, Triodopsis appressa and palliata. Here, also, we first notice the variation of Patula alternata towards heavy ribs upon its shell; which is still more apparent as the species extends towards the southwest.? Here, also, J/esodon elevata is often found banded.
The Cumberland Sub-Region is peculiar for the development of Zonites, and in the disintegrated genus Helix for the development of the section or genus Stenotrema, almost peculiar to these narrow limits.
(c.) The Southern Region comprises the peninsula of Florida, with the adjacent islands, together with the alluvial regions of the Atlantic and Gulf coasts. It includes, therefore, the eastern portion of North Carolina, South Carolina, Georgia, all of Florida, the southern part of Alabama, Mississippi, Louisiana, extending into Texas.’ Its boundaries, however, are but imperfectly known, and probably not accurately de- fined. Many of the species from the Interior Region and Cumberland
1 See Vol. I. pp. 122, 123. Being less adapted for cultivation than the balance of East- ern North America, we may hope for the preservation of our land shells in this Region, while they decrease rapidly before the advance of civilization elsewhere. See Jdid., pp. 182, 133.
3 This heavily ribbed form was common in Post-pleiocene days.
8 See Vol. I. 120, for a description of the Region.
GEOGRAPHICAL DISTRIBUTION. 35
Sub-Region have spread into its northern portion, and the following have extended over the larger portion of it :—
Macrocyclis concava. Triodopsis Van Nostrandi. Zonites fuliginosus. Mesodon albolabris. inornatus. thyroides. suppressus., Pupa pentodon. indentatus. fallax. arboreus. armifera. minusculus, contracta. Limax campestris. , rupicola. Patula alternata. corticaria. Helicodiscus lineatus. Vertigo milium. Strobila labyrinthica. © ovata. Stenotrema hirsutum. Succinea avara. monodon. obilqua. Triodopsis palliata. Tebennophorus Caroliniensis. tridentata. Pallifera dorsalis. fallax.
Equally wide over the Region has been the distribution of those minute species whose origin has been traced to circumpolar regions (see p- 26). Such are: Zonites viridulus, fulvus, and Vallonia pulchella.
In addition to these species derived from the north, are found the fol- lowing species peculiar to the Region, whose origin can be traced to the south, in the peninsula of Florida, from whence, indeed, many of them have not yet spread over the whole Region : —
Glandina truncata. Mesodon major.
Zonites cerinoideus. jejuna.
Polygyra auriculata. Mobiliana. uvulifera. Bulimulus Floridanus. Postelliana. Dormani. espiloca. dealbatus. avara. Cylindrella jejuna. cereolus. Pupa variolosa. septemvolva. modica. Carpenteriana. Succinea effusa. Febigeri. campestris. pustula. Wilsoni. pustuloides. Veronicella Floridana.
Triodopsis Hopetonensis.
Of the more widely spread species, Polygyra septemvolva is represented by various forms over the whole southern littoral region, both of the Atlantic and Gulf. So is Glandina truncata, Mesodon jejuna, Polygyra
36 TERRESTRIAL AIR-BREATHING MOLLUSKS.
pustula, pustuloides, and Pupa modica. Triodopsis Hopetonensis ex- tends only along the Atlantic alluvial Region. Bulimulus dealbatus is also distributed over the whole Region, from North Carolina to Texas, and has spread northward to Arkansas and Kentucky. Swe- cinea campestris extends along the Atlantic coast as far as South Caro- Kina, as does also Zonrites cerinoideus, even into North Carolina and Virginia. Polygyra espiloca and Postelliana have been noticed thus far in the southeastern corner of Georgia. The former also at New Orleans and Indianola. Swecinea Wilsonr, at Darien, Ga. Mesodon major ex- tends from the Gulf to Abbeville, S. C., confined to a narrow track of territory. ;
The following European encima been introduced by commerce into this Region, and still exist at the points named : Stenogyra decol- lata, Lin., Turricula terrestris and Pomatia aspersa, Miill., at Charleston, S. C.; Cecilianella acicula, Miill., Florida.
From the list of species peculiar to the Southern Region it will be seen that the prevailing form is Polygyra, a group or genus peculiarly American, represented in the Interior Region indeed, but meeting its greatest development here. The presence of Glandina and Veronicella shows, also, the more southern character of land-shell fauna. But the Region, and especially that portion of it from whence the fauna was distributed, i. e. the southern extremity of Florida, is still more peculiar in showing the connection between the land shells of the continent of North America and those of the West India Islands and the Spanish Main. Of the species given above (p. 35), Cylindrella jeyuna was, per- haps, introduced from Cuba, and Bulimulus Dormant may prove iden- tical with B. maculatus, Lea, of Carthagena. The following species have evidently been introduced? from the West India fauna :?-—
Zonites Gundlachi, Cuba, etc. Bulimulus Marielinus, Cuba. Patula vortex, Cuba, ete. Strophia incana, Cuba. Hemitrochus varians, New Providence. Stenogyra subula, Cuba, etc. Cylindrella Poeyana, Cuba. gracillima, Cuba, etc. Macroceramus Kieneri, Cuba. Liguus fasciatus, Cuba.
Gossei, Cuba. Orthalicus undatus, Cuba,
From Yucatan one species has been introduced, Polygyra oppilata.
1 Either by oceanic currents since the formation of the peninsula of Florida, or else from some island of the West India group, now enclosed in the peninsula. It is interest- ing in this connection to refer to the discovery, by Mr. Conrad, of a Tertiary fossil at Tampa Bay, Bulimus Floridanus, Conr. See also below, p. 40.
2 Also several non-pulmonate species, as Helicina subglobulosa, Cuba; Ctenopoma rugulosum, Cuba; Chondropoma dentatum, Cuba,
GEOGRAPHICAL DISTRIBUTION. 87
Bulimulus maultilineatus was introduced from the continent of South America,! where it has been found at St. Martha, N. Granada, and at Maracaibo and Pto. Cabello in Venezuela.
Florida has not only received several of its species from the West Indies, but also from its southern extremity it has contributed in return to the fauna of those islands. From hence, no doubt, Zonites arboreus has passed into Cuba and Guadaloupe ; Zonites minusculus to Cuba, Jamaica, Porto Rico (Bermuda?) ; Pupa fallax to Cuba; Vertigo ovata to Cuba; Zonites indentatus to San Domingo ?
From the various sources indicated above, the southern extremity of Florida has become inhabited by about seventy species of land shells, a number small in comparison with those found in the Cumberland Sub- Region (see p. 33), but large when compared with those found in the great Interior Region.
In addition to those species apparently originating in the peninsula of Florida and thence spreading over the whole Southern Region, there is found within its limits a number of species confined to the southwest- ern portion of the latter. These seem restricted to the southern part of Texas, which may be considered an offshoot of the Mexican fauna as shown by the presence of the genera characteristic of that country, such as Holospira, Bulimulus, and Glandina, Within the region, however, are many species peculiar to it, but belonging to the genera charac- teristic of North America, such as Polygyra and Mesodon. It seems, therefore, best to consider Texas as belonging equally to the fauna of North America and of Mexico, being the point where the two overlap. As the limits of the region are ill defined, several species extralimital to the State of Texas are included in the following catalogue of the Texan
Region : —
Glandina Vanuxemensis. Polygyra triodontoides. decussata. Mooreana. bullata. tholus. Texasiana. hippocrepis.
Zonites significans. Jacksoni.
caducus. Ariadne.
Microphysa incrustata. vultuosa.
Strobila Hubbardi. Mesodon divesta.
Polygyra ventrosula. Roemeri. Hindsi. Dorcasia Berlandieriana. Texasiana. griseola.
1 Or from some extinct fauna which also accounts for its presence at both points.
38 TERRESTRIAL AIR-BREATHING MOLLUSKS.
Bulimulus patriarcha. Stenogyra octonoides. alternatus. Pupa pellucida. Schiedeanus. Succinea Haleana.
Macroceramus Gossei. concordialis.
Holospira Goldfussi. luteola. Roemeri. Salleana.
Of the above Polygyra Jacksoni and Zonites significans are included with great hesitation. They are found at Fort Gibson, in Indian Terri- tory. They are more related to the fauna of the Cumberland Sub- Region than that of Texas.
Besides the species characteristic of the North American fauna which Texas has as a portion of the Southern Region of the great Eastern Province, we find in the above list two species peculiar to it of the char- acteristic American subgenus JJesodon, — Roemeri and divesta.?
Several species on the list have been introduced from other regions,® such as Strobila Hubbardi,* a Jamaica species, as well as Macroceramus Gossei, a Cuban species, which is also found on the Florida Keys. Jiero- physa incrustata from Cuba, as well as Pupa pellucida and Stenogyra octonordes.
Of the remaining species on the list, sixteen have actually been found in Mexico; probably all will be, as there seems no well-defined boun- dary here between the North American and Mexican fauna.
Bulimulus serperastrus, Say, although actually found in Texas, is evi- dently a member of the Mexican fauna, and is therefore omitted from my list, though included in the descriptive portion of my work.
The characteristic of Texas appears to be the great preponderance of the genus Polygyra, of the type of P. Zewascana, while the type of Flor- ida, the septemvolva, is almost wanting. The great abundance of indi- viduals is also remarkable, showing the Region to be peculiarly adapted
1 See Vol. I. 122, which gives the limits of the corresponding ‘‘ Southern Interior Sec- tion” such as would include these species, Several of the species of East Tennessee, also, have been found in Arkansas, —a fact also favoring a wider limit to the Cumberland Sub- Region.
2 This species has not actually been found within the limits of the State of Texas, but in the neighboring State of Arkansas and in Mississippi. To it may be applied the re- marks on Zonites significans and Polygyra Jacksoni above.
8 Hither by commerce, by oceanic currents, or from some former molluscous fauna of which these now isolated localities were offshoots.
4 Since the above was written, this species has been found by Dr. Newcomb near Sa- vannah, Georgia. It may therefore prove a widely distributed American species. In Jamaica it is known as H. Vendreysiana, Gloyne.
GEOGRAPHICAL DISTRIBUTION. 39
to pulmonate life. In the number of its species, also, the Texas Region is favored ; by adding to the above list of peculiar species those which it has in common with all of the Eastern Province, and also those of the Southern Region, we find a total of seventy species, the same num- ber as found in Florida.
On the accompanying map the Pacific Province is colored pink, the Central Province blue; the Eastern Province (of which the northern portions are not shown) is uncolored. The subdivisions, or Regions, of the Eastern Province are also indicated by colored lines. The red line marks the division between the Northern and Interior Regions. From this line the last-named region extends (its Sub-Region of the Cumber- land shown by green lines) to the brown and yellow lines, which, taken together, mark the northern boundary of the Southern Region, the yel- low separately indicating the Texan Sub-Region, the brown the Floridan Sub-Region.
In the above pages I have simply stated the facts now known regard- ing the actual distribution of our land shells, scarcely attempting to explain it. I will here venture to make a few suggestions on this sub- ject.
The student of geographical distribution must now take as his guide the recently published work by Wallace on this subject. From this he will learn that terrestrial mollusca of most of the recent genera have existed on the globe from very early geological times. Also, that, wherever originally appearing, their universal distribution over all the continents is easily explained. Thus we readily account for their pres- ence in North America,? and however imperfect may be the geological record, it shows us that at least Zonites, Pupa, Helix, Bulimulus, Vi- trina, Macrocyclis, and Clausilia existed here in previous geological ages. From these ancestors, no doubt, have been derived, through many intermediate stages of development, the present fauna. I have already shown that the characteristic American genera of the Eastern Province,
1 The Geographical Distribution of Animals, with a Study of the Relations of Living and Extinct Faunas as elucidating the past Changes of the Earth’s Surface. By Alfred Russell Wallace. Amer. ed. Harper and Brothers, New York. 1876.
2 In the following pages it will be seen that three well-established genera only — Hem- phillia, Prophysaon, and Ariolimax — are peculiar to our limits, excepting perhaps a few disintegrated Heliz.
40 TERRESTRIAL AIR-BREATHING MOLLUSKS.
the Mesodon, Triodopsis, Stenotrema, etc., were already established in post-pleiocene days. It is impossible to learn how much earlier they appeared, but of one significant fact we are certain, they are more recent than the elevation of the Rocky Mountains and Sierra Nevada, for otherwise these chains would not form, as now, dividing lines between the eastern, central, and pacific fauna. There are, indeed, several small species which have passed these barriers, being found over all of North America. These same species are found equally distributed in Asia and Europe. They are undoubtedly of much earlier origin than the strictly American species, and belong to some extinct fauna of world-wide dis- tribution. The circumpolar connection of the three continents has fa- cilitated their distribution. In this connection it is worthy of note that one of our existing species, now confined to America (Strobila laby- rinthica), is said to have existed in France in Tertiary days.
Our Southern Region has evidently been peopled from other fauna than that which supplied the Mesodon, Triodopsis, Stenotrema, etc., of the Interior Region. It was, no doubt, from some now extinct semi- tropical fauna that these came, but long enough ago to allow the Poly- gyras, Glandinas, etc. to be modified into species distinct from those which from the same common origin have become the equally well- established West Indian, Central American, and Mexican species.
The Central Province has, from geological causes, been more recently peopled by pulmonata than the Eastern Province. Its local species are less numerous. Patula is its characteristic genus, with species so vary- ing and intermingling one with the other that the student cannot refrain from noticing that they have the appearance of a species in a slightly advanced stage of evolution, each form not as yet established as distinct, easily recognized species.
The Pacific Province, also, presents in its variable, scarcely distin- guishable Ariontas, a fauna of comparatively recent growth, but whence its origin it is difficult to say.’
Finally, we have in the list of American land shells several species, purely local in their distribution, imported through the more or less direct agency of man. Of these, Pomatia aspersa was no doubt intro- duced as an article of food by foreign residents of Charleston, S. C., and seems to have established a hold there.? Zonites cellarius was intro-
1 See Dr. Cooper, as referred to on p. 18. 2 I have been asked what authority I have for this opinion, so think it worthy of state- ment that Charleston specimens belonging to the cabinet of the late General Totten still
THE JAW AND LINGUAL MEMBRANE. 41
duced by foreign shipping, probably around water-casks. It is also well known to have been introduced into other countries. The Limaces are found around human habitations; they seem to follow the English to all their colonies. The other foreign species mentioned on p. 36 have probably been introduced around the roots of plants, as have been other species which are from time to time sent me from greenhouses, gardens, etc. They are only local, except Z'achea hortensis, which may have been accidentally introduced in some other manner, since the dis- covery of America by Europeans, and owes its present distribution in the Northeast to its being peculiarly adapted to colonization. I have elsewhere related my successful attempt to colonize the allied Tachea nemoralis,*
Ill. THE JAW AND LINGUAL MEMBRANE.
In Volume II. my father paid great attention to the jaws and lingual membranes, figuring those of all the species which he could obtain. In continuing my father’s labors on the same subject, I had described and figured those of many other species. Thus, in a certain sense, it could be said that a great deal was known of these organs in our land shells. Unfortunately, however, these figures and descriptions had become of comparatively little value when the study of this subject had assumed such importance as of late. They did not give in sufficient detail the character of the individual teeth, however correct an idea they may have given of the general arrangement of the teeth upon the mem- brane. I was, therefore, induced to review the whole subject, and pre- sent it in a manner which would be of value as throwing light upon classification, in the Proc. Ac. Nat. Sc. Phila., 1875, pp. 140 — 243.
In their proper places under each genus and species will be found below the result of my re-examination of the subject. I will here repeat in full some general remarks on the organs treated of, and on their
retain a strong odor of the garlic which seasoned them for the foreign palate. I have my- self had specimens given me by French residents of the town where I reside, who had bought them as food in Philadelphia. The species has also been imported into Havana, Rio Janeiro, St. Iago, Chili, and other ports as an article of food. I found numerous liv- ing specimens in St. Michael’s churchyard in Charleston, S. C., in 1875, and in 1871 Pro- fessor Featherman sent me specimens from Baton Rouge.
1 See below, under 7. hortensis, in the descriptive portion of the work.
42 TERRESTRIAL AIR-BREATHING MOLLUSKS.
value for the purpose of classification, and on the bibliography of the subject. In rewriting this article for the present volume, I have con- sidered it best to redraw all the figures for the sake of greater accuracy, as well as artistic merit.
GENERAL REMARKS.
As many of my readers are quite unfamiliar with the subject, espe- cially most of those who have so largely contributed specimens for ex- amination, I will describe in detail the position of the organs and the method adopted for their study.
On holding up against the light an individual of Mesodon thyroides in one hand, and offering to him with the other some food (a piece of lettuce or carrot is always acceptable), one can readily see with the naked eye the two organs here treated of. Above the external opening of the mouth, through the tranparent tissue of the head, is seen a small, arched, reddish, free instrument, which appears to rise and fall as if used in cutting off morsels of food. This is the jaw.
On the floor of the mouth is the lingual membrane, occupying about the position of the human tongue. Its color is too nearly the same as that of the head to afford any strong contrast, but, with close atten- tion, it will be detected by its glistening silvery appearance, as it works backward and forward. Its use seems to be to rasp the food and also to force it back into the cesophagus.
More detailed description, fully illustrated by figures, of the position of these two organs, will be found in the chapters on Special Anatomy in Volume I. (See also below, Chapter IV.)
MetnHop oF EXTRACTION.
On opening the head of Mesodon thyroides from above, one readily notices at the extreme anterior part, close against the outer integument, a prominent oval body.? This is called the buccal mass. It is easily cut away from the animal, and will be found to contain both jaw and lingual membrane. ‘These can be removed by fine scissors or knives from the buccal mass in the larger species, but in the smaller species the method usually employed is putting the whole buccal mass in a
1 I must earnestly beg my readers to be deterred from this examination by no imagi- nary difficulties. It is the simplest and easiest process. Indeed, the same may be said of examination of the complete anatomy. All that is required is to carry it on under water. The various organs are then readily separated.
THE JAW AND LINGUAL MEMBRANE. 43
watch crystal’full of a strong solution of caustic potash. Allowing it to remain for several hours, the potash will destroy all of the buccal mass, and leave the jaw and lingual membrane perfectly clean and ready for examination. They remain attached, if the solution is not too strong, showing a connection between the two. They must be well rinsed in clean water, in another watch crystal, before examination. Another more expeditious process is to place the whole buccal mass in a test-tube, with the solution of potash, and boil it for a few seconds over a spirit lamp. Pouring the contents of the test-tube into a watch crystal, the lingual membrane attached to the jaw will be readily seen by a pocket lens. If the species be very small, as Patula striatella for instance, its whole body may be thrown into the solution. Still more minute species, as Zonites melium for instance, may be treated in this way: crush the whole shell between two glass slides, wash away the particles of the broken shell in a few drops of water, still keeping the body of the animal on the slide; when clean, drop on it the caustic potash and boil it by holding the slide itself over the spirit lamp.
On MountTINaG. *
For the purpose of examination, the jaw and lingual membrane may be simply mounted in water and covered with thin glass. One must be sure to spread out the lingual membrane, not have its upper side down, and it will be well to cut it transversely in several places, as the teeth are beautifully shown, and often stand detached, on the edges of the cut.
For preservation for future study I hesitate to recommend any process, as I know of none which has been tried for a sufficiently long time. I have myself lost many specimens by imperfect mounting. Canada balsam, formerly used, ruins the membrane by rendering it too transparent. The glycerine mounting fluids, now in use, certainly pre- serve a membrane for several years, but they have not been tried many years, and have the great disadvantage of deliquescing in warm weather.
ON THE JAW.
The jaw and lingual membrane, having been mounted, must now be examined under the microscope.
The jaw will be found to vary greatly in its characters in the different genera. It is either in one single piece; in one single piece with an
44 TERRESTRIAL AIR-BREATHING MOLLUSKS.
accessory quadrate piece attached to its upper margin; or in separate, detached pieces, free on their lower edges, usually soldered together into one single piece above. It differs also in being with or without a median beak-like projection to its cutting edge; also in its ends being more or less acuminated ; but still more by the presence or absence of strize or rib-like processes on its anterior surface. When present, the ribs are found in every degree of development, passing quite across the jaw and denticulating one or both margins, or only developed on the lower portion of the jaw, and crenellating the lower margin. The ribs are often almost obsolete, or represented by wrinkles or coarse striz. They are present on the anterior surface of the jaw only, or on both anterior and posterior surfaces. They are distant, narrow, stout, few; or crowded, broad, stout, and numerous. Their number is within certain limits inconstant in the same species. They sometimes are very broad, and seem like separate plates soldered to the anterior surface of the jaw, or to be formed by a folding of the jaw upon itself. When this appearance of folding into plates is given, it will generally be found that the plait-like sections are actually separated by distinct, but deli- cate ribs. When this form of ribs is found, they are either vertical or inclined obliquely towards the median line of the jaw. Sometimes this last arrangement is developed to such a degree that the delicate ribs meet before reaching the bottom of the jaw, and a triangular compart- ment is left at the upper centre of the jaw, its base being upward. This form of jaw is usually thin and membranous.
When the jaw is striated and not ribbed, the striz are vertical, or they converge towards the median line. There are often transverse striz also, and transverse lines of reinforcement.
The upper margin of the jaw is often extended into a stout membra- nous attachment, apparently of the same material and consistency as the jaw itself, and showing the same continuity of structure by the strie of the jaw extending into it without interruption. This is not the accessory quadrate plate mentioned above.
The jaw is found in every degree of consistency, from very thick to quite membranous and almost transparent.
The cutting margin of the jaw is smooth, crenellated, or denticulated. It is simply concave, or furnished with a more or less developed beak- like median projection.
In shape the jaw ranges from scarcely arcuate, long, low, to horse- shoe-shaped, short, high.
: 4 7 ‘
es
THE JAW AND LINGUAL MEMBRANE. 45
It will be seen below that these peculiarities of the jaw, taken in con- nection with the characters of the lingual membrane, have till now appeared to furnish reliable characters for classification. It must be confessed, however, that exceptions to the usual constancy of characters have been noticed in some genera; sometimes the difference between strive and ribs is difficult to determine ; sometimes the beak-like promi- nence is greatly modified by a simple median projection. In some genera, for instance Dentellaria, the character of the jaw is not generic.
THe Lincuat MEMBRANE.
In placing the lingual membrane under the microscope, we at once perceive that it is (at least in most of our genera) a long,’ narrow, ribbon-like organ, whose whole surface is covered with numerous small tooth-like processes, whose reflected apices are pointed, the. points directed towards the cesophagus, to which, as stated above, they serve to move the food, as well as.to perform a rasp-like mastication. These teeth are arranged in two series of rows, one running longitudinally, the other transversely.
On careful examination it will be seen that all the teeth of each successive longitudinal row are of the same form,” but that there are several types of teeth in the different parts of each trans- verse row. Three of these types are found, the central tooth, Veneer Nett eee Two transverse rows of teeth of Strobila labyrinthica. of the central, called /aterals, and the teeth extending from the laterals to the outer margins of the membrane, called marginals. The change from the single central to the laterals is usually abrupt, but from the laterals to the marginals it is usually gradual, so that there are several teeth intermediate between the two, which may be called transition teeth. The transverse rows of teeth are similar on each side of the cen- tral tooth, so that it is necessary to figure only one half of one trans- verse row, with its central tooth, to give an idea of the whole transverse
1 It is very broad in Orthalicus, Liguus (see Pl. XVI.), some subgenera of Acha- tinella, some Bulimuli, etc. ; in some subgenera of Cylindrella it is very narrow. On this same plate I have given figures of the membranes of the various genera, with a line showing the direction of one transverse line of teeth.
2 Even in case of malformation this holds true. I have often found a misshapen, or otherwise abnormal tooth, repeated down the whole length of the membrane, or even that a tooth may be entirely wanting in its whole length.
46 TERRESTRIAL AIR-BREATHING MOLLUSKS.
row, or, indeed, of the whole membrane, as all the longitudinal rows, as stated above, have similar teeth. (See Fig. 3.) These transverse rows differ in the various genera as to their direc-
Fig. 8. tion, either straight, ob- RU CRC <> | lique, or curving, or a : WAY AY Ly Ved , 4 . REIT ne i) tina, 2 | combination of these di-
RAMS WW STEEN VATA & P
rections. One half of two transverse rows of teeth of Sten. hirsutwm.
- Of the three types of
teeth, central, lateral, and marginal, one or more may be wanting. Their number, however, is approximately constant in different individ- uals of the same species, so that, as a specific character, the count of the teeth on one transverse row is usually given; thus in Zonites inornatus I find about 23— 1— 23 teeth, that is, 23 teeth on each side of the central tooth, making 47 teeth in the entire transverse row.
The characters of the individual teeth vary greatly in the various genera, especially in some of the genera foreign to our limits. In most cases, however, there are two distinct types of teeth, the guadrate and aculeate. The former is shown in my figure (Fig. 4). a, 8, ¢, d, is the portion of the tooth which rests upon the membrane; I have called it the base of attachment. It varies in its proportional length, and in the greater or less expansion of the lower? lateral angles. The upper margin of this base of attachment is broadly reflected ; e marks the reflected portion, which I term the reflection. It is usually tri- cuspid, the median cusp h being much longer than the side cusps ff. These last are sub-obsolete in some species. All the cusps are in most
Fig. 4. cases surmounted by distinct cutting points ;* | 7 is the median cutting point, gg the side cut- ting points. These cutting points are not always present on the side cusps, and, even when pres- ent, are sometimes not readily detected. In- BRNO a ads t deed, this is the most difficult point of study of
cana. the whole membrane. The cusps and cutting points vary in development in the various species, and somewhat so in different portions of the same membrane. It must also be borne in mind, while studying my figures of the teeth, that the median cutting
1 T use the term upper and lower to describe the figure I give of the base of attachment. More properly I should say anterior and posterior, to describe their position on the mem- brane, in reference to the head of the moving animal.
_ 3 The cutting points are shaded in my figures.
THE JAW AND LINGUAL MEMBRANE. 47
point is flat on its lower surface, that is, the surface nearer the base of attachment, but from thence it first rises and expands greatly at its sides, and then gradually decreases in size as it still rises Fig. 6. and arches over the top. Thus under the microscope there are two planes prominently seen by changing the focus of the instrument, the plane of the lowest portion of the cut- ting point, and the plane of its greatest expansion. In Fig. 5 the former is shown by dotted lines, the latter by the continuous line. In my illustrations the former alone is given. I regret not having shown both as done by Sem- per in Phil. Archip. 1. c., especially as the plane of the pirct lateral of Z: greatest expansion often shows a lateral bulging represent- /™“'s'n25™s- ing the side cutting points in species deprived of distinct side cutting points.
The median cutting point seen on the plane of its greatest expansion,
as in my figure, appears to spring from the median cusp itself, as if it were not distinct from it. A great deal has still to be done in eluci- dating the true character of cusp and cutting point.
The other type of tooth, which I call aculeate (see Glandina), differs in not having a quadrate base of attachment, but usually one of a somewhat sole-like form. Its upper margin is not reflected, but from its whole surface springs a single large cutting point, usually thorn- shaped, but sometimes more spine-shaped. The apex of the cutting point is sometimes bifid, or even trifid, even in the same genus.
Of these two types, quadrate and aculeate are all the teeth now known. Of the quadrate type many and dissimilar forms are known, but all have the quadrate base of attachment.
The characteristics of central, lateral, and marginal teeth are given under each genus or subgenus.
On CLASSIFICATION,
The characters of the jaw, combined with those of the lingual mem- brane, furnish reliable bases of classification. They have been consid- ered of various weight by different writers. I here propose to treat them as guides only to the greater division of the Pulmonata. In grouping the genera it will be necessary to include all, both native and foreign to America, in order to properly appreciate the value of this arrangement.
1 I must not be understood to propose a system of classification. I merely place the genera into certain groups, independent of their divisions into families.
48 TERRESTRIAL AIR-BREATHING MOLLUSKS.
Taking, therefore, the whole series of known Pulmonata Geophila, the first grand division is based on the absence or presence of a jaw. Of the former are the following: Testacella,! Daudebardia,? Streptaxis,® Rhytida,* Diplomphalus,’ Strebelia?® Glandina,’ Petenia?® Spiraxis?® Streptostyla,” Ravenia?™ Strepstostele," Cceliaxis?* Gonospira,4 Gib- bus 21> Ennea, Vaginulus.™
All the above have aculeate marginal teeth; the lateral teeth are always absent ; the centrals in some of the genera.
The following genera have quadrate marginal teeth: Onchidium,”* Peronia,® Buchanania?®
The second grand division contains those genera haying a jaw. In this division also we find some genera with aculeate, and some with quadrate, marginal teeth.
Of the former are: Zimazx,”* Lbycus,” Parmacella,* Tennentia,* Mari- ella ?* Parmarion,*® Dendrolimax,” Phosphorax?*® Urocyclus?™® (1 know nothing of the position of Othelosoma, Aspidorus, and other problemati-
1 Heynemann, Malak. Blatt. X. Pl. II. Fig. 5.
2 Goldfuss, verh. Naturh. Vereins der preuss. Rheinl. und Westphalens, 13th year, 1856, Pl. VI. Fig. c. cl.
8 Heynemann, Malak. Blatt. XV. Pl. IV. Fig. 2.
4 Semper, Nachr. der deut. Malak. Gesellschaft II. 102.
5 Fischer and Crosse, Journ. de Conch., XXI. 21, Pl. III. Fig. 8.
6 Jaw and dentition unknown.
7 See this work. 8 Jaw and dentition not actually known.
9 Jaw and dentition not actually known; as restricted, the genus may be more correctly placed near Stenogyra.
10 Fischer and Crosse, Moll. Mex., p. 16, Pl. IV. Fig. 2. .
11 Jaw and dentition not actually known.
12 Heynemann, Nachr. mal. Gesel. I. 20, 177, Fig. 5.
18 Jaw and dentition not actually known.
14 Bland and Binney, Amer. Journ. Conch., V. 37, Pl. XI. Fig. 1, photographed.
15 No doubt like the last.
16 Heynemann, Nach. Mal., Gesel. I. 20, 177, Pl. XX. Figs. 3, 4.
17 See Stolicska, Q. Journ, As. Soc. Bengal. n.s. XLII. Pt, II. p. 33-37. The name Vaginulus is restricted by him to the agnathous species, while Veronicella includes those furnished with a jaw.
18 Bland and Binney, Ann. Lyc. N. H. of N. Y., X. p. 340, Pl. XVI. Figs. 3-5.
19 Quoy, Voy. de l’Astrolabe, Pl. XII.
20 Jaw and lingual unknown.
21 See this work.
22 Heynemann, Malak. Blatt. X. 142, Pl. I. Fig. 3.
28 Semper, Phil. Archipell., 90.
24 Semper, 1. c. 1, Pl. VI. Fig. 17.
2 Tb. 12. 6 Tb. 9,-Pl. VI. Fig. 16.
27 Heynemann, Malak. Blatt. XV. Pl. I. Fig. 1.
28 Jaw and tongue not known.
29 Heynemann, Malak. Blatt. 1866, 70, Pl. XI. as Parmarion flavesceus,
OO, a a
THE JAW AND LINGUAL MEMBRANE. 49
cal genera.) Vitrina,’ Vitrinordea,? Vitrinopsis,® Nanina,* and all the genera now recognized in its disintegration, Stenopus,® Vitrinoconus,® Macrocyclis," Zonites.®
The following genera have quadrate marginal teeth. They may be readily grouped by the character of their jaw, which is either in one single piece (4), in one single piece with an accessory upper quadrate piece (#), or in numerous pieces (C). !
A, Those whose jaw is in one single piece may again be subdivided into several groups based on the absence, presence, and peculiarities of the ribs on their jaw. This division, however, is unsatisfactory, as these characters are not always well marked.
(a) Jaw without ribs: Philomycus,® Parmella?” Oopelta,4 Sagda, Patula,* Polymita,4 Hemitrochus,” Helicodiscus,® Onchidella,™ Acavus, Corilla, Caryodes, Panda, Labyrinthus, Caracollus, Leucochroa,® Cysti- copsis?™® Plagioptycha,™ Leptoloma,” Anostoma,™ Anostomella?™ Tomigerus? Boysia? Plectostoma ? Hypselostoma ?* Achatinella,*® Clausilia,” Steno- gyra,* Strophia,” Buliminus,® Balea,® Pupa,” Vertigo,® Ferussacia,™ Cecilianella,® Geostilbia ? Azeca? Tornatella ?* Zospeum ?* Holospira,®
1 See this work. 2 Semper, I. c. 85, Pl. IX. Fig. 33. 8 Ibid. 86, Pl. XI. Fig. 26. 4 Ibid.
6 Bland, Ann. Lyc. N. H. of N. Y., VIII. 158, Fig.
6 Semper, l. c. 91, Pl. XI. Fig. 27. 7 See this work.
8 See this work. # 9 See this work.
10 Jaw and lingual dentition unknown. 1 Heynemann, Malak. Blatt., XIV. Pl. I. 2.
12 Bland and Binney, Am. Journ. Conch., VI. 177. 18 See this work. 14 Bland and Binney, Ann. Lyc. N. H. of N. Y., X. 341, Pl. XVI. Fig. 1. 15 See this work. 16 See this work. 17 See this work.
18 See Semper, 1. c. No doubt other genera of disintegrated Helix will be found to be grouped here. I propose at present to remove from Helix all the species not having ribs upon their jaw.
19 Bland and Binney, Ann. Lyc. Nat. Hist. of N. Y., X. 220.
20 Ibid., IX.
21 Proc. Ac. Nat. Sc. Phila. 1874, 56. 22 Ibid. 58.
28 Journ. de Conch., XIX. 261, Pl. XI. Fig. 4.°
24 Jaw and dentition unknown.
25 Jaw and dentition unknown.
_% Bland and Binney, Ann. Lyc. N. H. of N. Y., X. 335, Pl. XV. Figs. 6, 7.
27 Troschel, Moquin-Tandon, Lehmann, etc.
28 See this work. 29 See this work.
80 But some species have ribs. See Moquin-Tandon, Lehmann, ete.
81 Moquin-Tandon, Moll. Fr., Pl. XXV. Fig. 6.
82 See this work. 83 See this work. & See this work.
85 See this work. 86 Unknown.
87 Heynemann, Mal. Bl., X. Pl. III. Fig. 14. Jaw unknown.
88 See this work.
50 TERRESTRIAL AIR-BREATHING MOLLUSKS.
Eucalodium, Ceelocentrum,? Lithotis,? Rhodea, Megaspira,* Limicola- ria,® but one species has a ribbed jaw, Achatina,® Pseudachatina ? Peri- deris? Columna?' Bulimus as now constituted has various forms of jaw.
(>) Jaw with decided stout ribs: Anadenus,’ Arion, Ariolimax, Pro- physaon, Pallifera, Veronicella, Binneya, Hemphillia, the genera of dis- integrated Heliz,® Geomolacus,” Letournexia," Peltella,* Xanthonyx,™ Simpulopsis,* Pfeifferia,® Berendtia,” Carelia,™ and, as stated above, some species now included in Bulimus, Cochlostyla, Buliminus, Limi- colaria.
(c) Jaw with separate, delicate ribs, usually running obliquely to- wards the centre: Geotis,® Amphibulima,” Bulimulus, Cylindrella, Ma- croceramus,” Pineria,” Partula.™
B. The genera whose jaw is in one piece with an accessory quadrate piece are Succinea,* Omalonyx,* Hyalimax,® Athoracophorus.*
C. The genera whose jaw is in separate pieces are Orthalicus, Liguus, and Punctum.™
I have arranged the American genera in the same manner in the follow ng pages.
1 See Crosse and Fischer, Journ. de Conch., 1870, Pl. V. Fig. 1.
2 Jaw and dentition unknown.
8 Binney, Proc. Phila. Ac. Nat. Se. 1874, Pl. V. Fig. 3.
4 Jaw and dentition unknown.
5 Bland and Binney, Amer. Jour. Conch., VII. 181.
6 Von Martens, ed. 2, p. 201.
7 Jaw and dentition unknown.
8 Heynemann, Malak. Blatt., X. 138, Pl. I. Fig. 1. ® See this work. 10 Bland and Binney, Ann. of Lye. of N. H. of N. Y., X. 309, Fig.
11 Bourgignat, Moll. nouv. et lit., VII. 201, Pl. XXXIV. Figs. 1-7.
12 Jaw apparently ribbed in Férussac’s figure, Pl. VII. A.
13 Fischer and Crosse, Moll. Mex., Pl. IX. Figs. 15, 16.
14 Shuttleworth, Diag., No. 6, p. 147.
15 Morch, Journ. de Conch., 1865, 385.
16 Crosse and Fischer, Journ, de Conch., 1870, Pl. V. Figs. 11, 12.
17 Binney, Pr. Phila. Acad. Nat. Sc. 1876, p- 185.
18 Bland and Binney, Ann. Lye. N. H. of N. Y., Vol. X. Pl. XI. Figs. 1, 5- 7. 19 Proc. Phila. Ac. N. Sc. 1874, Pl. VIII. Figs. 2, 5, 6. Pellicula is a synonyme of this.
20 See this work. 21 Bland and Binney, Ann. N. Y. Lye. N. H., X. 22. 22 Binney, Ann. Lyc. N. H. of N. Y., XI. 45. 23 See this work. 24 Malak. Blatt., X. Pl. IV. Fig. 5, a.
25 Fischer and Crosse, Journ. de Conch., XV. 218, Pl. X. Figs. 5, 7.
26 Bergh, verh. kais. keenig. zoolog. botan. Gesell. in Wien., XX. 844, Pl. XII. Figs. 2, 4, 5.
27 See this work.
THE JAW AND LINGUAL MEMBRANE. 51
BIBLIOGRAPHY.
The principal works on lingual dentition referred to are :—
Leipy in Binney’s Terrestrial Air-Breathing Mollusks of the United States. Boston, 1851, Little & Brown. The wood-cuts of lingual mem- branes are misplaced in the text. See the list, Vol. II. p. 358.
Binney and Bianp. Land and Fresh-Water Shells of North America. Part I. Smithsonian Miscellaneous Contributions. Washington, 1869. Morse in Journal of the Portland Society of Natural History, 1864.
Moaguin-Tanpvon. Histoire Naturelle des Mollusques Terrestres et Fluviatiles de la France. Paris, 1855.
Fiscuer et Crosse. Etudes sur les Mollusques Terrestres et Fluvia- tiles du Mexique et l’Amérique Centrale. Paris, 1874.
LrHMANN. Die lebenden Schnecken und Muscheln der Umgegend Stettins und in Pommern. Cassel, 1873.
GoupFuss. Verzeichniss der bis jetzt in der Rheinprovinz und West- phalen beobachteten Land- und Wasser-Mollusken, nebst kurzen Be- merkungen tiber deren Zungen, Kiefer, und Liebespfeile. Von Ver- handlungen des naturhistorischen Vereins der preussischen Rheinlande und Westphalens. 13 Jahrgang. Bonn, 1856.
Semper. Landmollusken. Reisen im Archipel der Philippinen. Wiesbaden, 1873.
HEYNEMANN. LEinige Mittheilungen tiber Schneckenzungen, mit be- sonderer Beachtung der Gattung Limax. Von Malako-zodlogische Blat- ter, X. 1862.
Von Martens. Die Heliceen von Jou. Curist. AuBers. Zweite Ausgabe. Leipzig, 1860.
These are the principal works referred to. The references to shorter papers in various periodicals will easily be understood.
ON THE ILLUSTRATIONS OF DENTITION.
I endeavored in the paper already referred to, and in my subsequent papers, to give a good view of the central, lateral, and marginal teeth of each species, with the transition teeth of many of the species. The portion of the membrane chosen is different in the various species of each genus or subgenus, in order that the variations in the form and de- velopment of cusps and cutting points may be shown. Thus in some figures I have selected the part of the membrane where the marginal teeth have a very blunt cusp, while in others they are shown much
52 TERRESTRIAL AIR-BREATHING MOLLUSKS.
more graceful. It must constantly be borne in mind that on any one membrane the teeth vary considerably in regard to this point.
In illustrating the general arrangement of the teeth upon the lingual membrane, I have used the wood-cuts in the text prepared for my former works and papers, mostly by Mr. Morse, and a few by Dr. Leidy, prepared for my father’s work. It must be remembered that these figures do not represent correctly the characters of the individual teeth.
I have also used in the text figures of the jaws of many genera and subgenera, prepared for the Land and Fresh-Water Shells of North America, Part I. The jaws of the more recently described genera and subgenera I have myself illustrated from drawings by camera lucida.
ON THE VALUE OF THE JAW AND LINGUAL MEMBRANE FOR THE PURPOSE OF CLASSIFICATION.
It is conceded by all recent students of land shells that for the larger divisions the presence or absence of a jaw and the aculeate or quadrate form of marginal teeth are reliable characters.
The characters of the jaw and separate teeth of the lingual membrane have also been used in various ways for grouping the genera into fami- lies, etc., and even of grouping species into genera. I refrain from any discussion of their value for such purposes, simply because I believe our material is far too limited. It seems as if I can better employ my time in patiently accumulating new facts. I can, however, venture to say that the character of the jaw and teeth seems to be more constant in some genera than in others. It appears, for instance, that in some genera the presence or absence of lateral teeth is not a generic character, though in others it iss The same may be said of the presence or ab- sence of side cutting points to the centrals and laterals, and the greater or less development of their side cusps ; also in the bifurcation or non- bifurcation of the cutting point of aculeate marginal teeth ; also as to the presence or absence of ribs on the jaw.
It will, I believe, be proved that certain genera are constantly char- acterized by a peculiar form of teeth, while others have a considerable range of variation. I might, perhaps, add that when the genus is numerous in species, there is a much greater chance of finding a varying dentition. If this latter proves true, we shall be obliged to concede that there are certain types of teeth which may be found among species of some of the larger genera, though some of the smaller genera are
SPECIAL ANATOMY. 53
much more, if not absolutely, restricted to one single type of dentition. I do not venture any further deductions at this time.
I will add that all the figures of dentition in the plates have been drawn by my own hand from the microscope itself, with the aid of the camera lucida,
IV. SPECIAL ANATOMY.
Tue following pages are reproduced from the treatise on the subject by Dr. Leidy prepared for Volume I. I have added notes on the more recently discovered genera.
GENERAL REMARKS UPON THE EXTERIOR ForRM AND STRUCTURE OF THE TERRESTRIAL NAKED GASTEROPODA.
Upon examining a Zimax or an Arion, we find it composed of a thick, vermiform body, with a broad, ribbon-like, pedal disk, running the whole length of its inferior surface. The anterior obtuse extremity forms the head ; and from it protrude two retractile tentacula, and two retractile eye-peduncles, upon the outer side of the tip of the two latter of which is placed the eye. The mouth is situated at the antero-infe- rior part of the head ; and immediately below it is a deep depression or blind sac. The posterior part of the body forms the tail, and is acute. Upon the antero-superior part of the body is placed the mantle, which covers the pulmonary chamber, and contains within it a rudi- mentary, laminar, calcareous testa or a congregation of calcareous grains. In other genera these are wanting. The anterior part of the mantle is free and movable, and the head, indirectly through the retractor muscle of the buccal body, is capable of being retracted be- neath it. On the right edge of the mantle the pulmonary orifice exists ; and at the posterior side of the latter the anal aperture is placed. Upon the right side of the head, a short distance posterior to the eye-peduncles of that side, the genital orifice is situated. The body has two distinct cavities, — the pulmonary chamber, containing a vas- cular network upon its surface, the heart, the renal organ, and the rec- tum ; and the visceral cavity, separated from the former by a muscular
54 TERRESTRIAL AIR-BREATHING MOLLUSKS,
partition, containing the digestive and generative apparatus and the nervous centres.
Ariolimax and Prophysaon have the same general arrangement as LIimax and Arion. Hemphillia is distinguished by having its shelly plate external, its edge lightly imbedded in the mantle.
In Vebennophorus and Pallifera the mantle covers the whole upper surface of the body, and encloses no testaceous rudiment. Its anterior edge is unattached, and the head is retractile beneath it. The pulmo- nary chamber is placed beneath the anterior part of it ; and the muscu- lar membrane, bounding the visceral cavity in a great part of its extent, is but loosely attached to the outer integument.
In Veronicella the body appears broad from the mantle, which en- closes the whole body except the comparatively narrow pedal disk, form- ing a lateral, angular projection as it is inflected inferiorly to the margin of the pedal disk. In transverse section it is semi-elliptical. The man- tle contains no testaceous rudiment. The head can be but slightly protruded. The tentacles are bifid. The respiratory orifice is situated on the right side of the tail, between it and the extremity of the pedal disk. The anal aperture opens at the posterior margin of the latter orifice. The generative apparatus has two distinct external apertures, distant from each other. The male genital orifice is placed just beneath the mouth, between it and the blind sac, inclining to the right. The female orifice is situated upon the inferior part of the left side of the mantle, midway between the head and tail. As usual, the body has two cavities, of which the pulmonary occupies a position at the right posterior part, beneath the mantle, and extending backwards on the right to the tail.
Onchidium has a similar arrangement to Veronzcella, but has no ten- tacles.
GENERAL REMARKS ON THE TERRESTRIAL TESTACEOUS GASTEROPODA.
A testaceous gasteropod resembles a slug with the greater portion of the viscera squeezed out upon the back, and arranged in a turbinate manner. The turbinate mass is always an exact mould of the testa- ceous covering of the animal ; its length in the spiral direction holds no proportion with that of the foot, or that part of the body which the animal protrudes from the shell, and differs very much, not only in dif- ferent genera, but also in different species of the same genus. With an increase in length a proportionate decrease in breadth is observable,
SPECIAL ANATOMY. 55
and wice versa. In Cylindrella it reaches its maximum length and nar- rowness ; in Succinea it has the minimum length, and the greatest pro- portionate breadth. When the foot is protruded from the shell, every part of the exterior surface of the turbinated mass is still in contact with the interior surface of the latter, and is retained so by means of the comparatively capacious pulmonary chamber. When the foot is retracted, it is at the expense of the latter cavity ; so that the pulmo- nary chamber of the testaceous genera is as much larger than that of the naked genera as the size of the foot superadded, whilst the extent of the pulmonary network of blood-vessels remains the same.
The testacea have a muscle which is peculiar, namely, the retractor- muscle of the foot, which has its origin, in common with the retractors of the eye-peduncles and buccal body, from the columella of the shell. Narrow at its commencement, it increases in breadth, splits into several bands, and diverges as it descends to get its insertion into the whole of the inner margin of the excavation of the foot, excepting anteriorly, where its place is occupied by the retractor of the buccal body. |
The head occupies the anterior portion of the foot, and in Helix, Bu- limus, Pupa, and Succinea, etc., offers nothing peculiar from that of Limax. In Glandina a third pair of tentacular appendages exists. These are non-retractile, auriculate in form, and originate just postero- inferiorly to the base of the inferior, retractile tentacles, and project horizontally backward. |
The body of the testacea, like that of slugs, has two great cavities. The visceral cavity includes the greater part of the turbinated mass and the excavation of the foot. The pulmonary chamber occupies a position on the outer side of the lower one to three whorls of the turbi- nated mass. The collar apparently takes the place of the mantle in slugs. In all the genera it is attached around the base of the turbi- nated mass, and is perforated on the right side by the pulmonary orifice. On the outer border of the latter the anal aperture is placed.
As in slugs, the genital orifice is situated on the right side of the head, more or less posterior to the eye-peduncles in the respective genera.
ON THE TEGUMENTARY COVERING OF THE TERRESTRIAL GASTEROPODA.
Besides a testa capable of enclosing the whole body, which most of the terrestrial Gasteropoda possess, they have a thick envelope, com- posed of mucous and muscular membrane. The exterior, highly irri-
56 TERRESTRIAL AIR-BREATHING MOLLUSKS.
table, and contractile investment consists of an actively secreting mucous membrane (Figs. 5, 6, 7, 7) with a substratum of interlaced muscular fibres (2). In the naked genera it is pretty uniformly developed
Fig. 5.
Fig. 5 isa diagram representing the disposition of the coverings of the body in Limaz and Arion. 1, mucous lamina; 2, muscular substratum ; 3, muscular peritoneum ; 4, visceral cavity ; 5, rudiment- ary testa; 6, pulmonary chamber.
throughout, but is thickest upon the pedal disk, the tail, and the upper surface of the mantle, and thinnest upon the head, eye-peduncles, and reflected border of the mantle.
Fig. 6.
Fig. 6, disposition of the tegumenta in Tehennophorus. 1, mucous lamina; 2, muscular lamina; 8, peritoneum; 4, visceral cavity; 5, pulmonary chamber; 6, interval between the two muscular layers.
In the testaceous genera, upon the part of the body corresponding to the interior of the shell, it appears as if the mucous layer had been pushed downwards to form the collar (Fig. 7, /*); but it may be still traced over the surface of the turbinated portion, as a delicate, tessel- lated epithelium.
The mucous glands are very numerous in the mucous layer; its epithelial cells are flattened, from three to six sided, granular, and with large, round nuclei.
The muscular substratum (Figs. 5, 6, 7, 2) of the mucous lamina is composed of unstriped fibres, arranged transversely, obliquely, and lon- gitudinally. It is inflected outwards beneath the mantle, in Limax and Arion, to form the outer parietes of the pulmonary chamber. Between
SPECIAL ANATOMY. 57
this portion and the mucous layer is placed the rudimentary testa (Fig. 5, 6). In Zebennophorus it is inflected inwards (Fig. 6, 5) be- neath the anterior portion of the mantle, to form the parietes of the pulmonary cavity. Its transverse fibres predominate within the eye- peduncles, its longitudinal fibres, in the exterior pulmonary parietes of
Fig. 7.
Fig. 7, disposition of the tegumenta in Helix, Bulimus, etc, The references are the same as in Figs. 6 and 6, except 1*, which is the collar. the testaceous genera, and especially accumulate on the outside of and parallel to the rectum, so as to serve as an efficient agent in the retraction of the collar, and an aid in the expulsion of matters from the rectum.
Interior to the musculo-mucous investment of the body is a second
covering (Figs. 5, 6, 7, 3), which may be considered as a sort of perito- neum. It is a muscular membrane, and encloses the digestive and generative apparatus. It is usually pretty closely attached to the outer tegument, except in Zebennophorus Caroliniensis, in which the two are separated in all parts of the body, except above the pedal disk, where they are firmly blended together, as in all Gasteropoda. It forms the partition or diaphragm between the visceral and pulmonary cavities. This membrane is composed of transverse and longitudinal, unstriped, nuclear fibres, and is the origin of the especial retractor muscles of different organs.
Or THE DIGESTIVE APPARATUS.
Limax. The orifice of the mouth is bounded by a pair of contractile lips, is situated at the anterior part of the head, and opens into the cavity of the buccal body. When the latter is retracted by its peculiar muscle, the oral orifice becomes lengthened into a canal by the inversion of a portion of the external integument.
The buccal body is an irregularly oval-shaped, muscular organ, re-
58 TERRESTRIAL AIR-BREATHING MOLLUSKS. |
sembling in appearance a gizzard, and contains within it the mastica- tory apparatus. Just within the upper lip, attached to the entrance of the buccal body, is the dental plate or jaw, —a crescentic, corneous lamina, used for cutting the food. Its anterior face is convex, and presents several vertical ridges. Into its upper convex edge a band of muscular fibres is inserted, by the contraction of which the inferior, concave, cutting edge is advanced beyond the line of the upper. The middle of the cutting edge is extended into a short, conical beak. This jaw is brought into view when the animal is eating, by the advance- ment of the buccal body. The floor of the cavity is occupied with a gouge-shaped, muscular tongue,’ the tip and upper surface of which are free, and are covered by a corneous lamina studded with a great num- ber of conical dentures, with the points projecting backwards, arranged in transverse rows. These teeth preserve the same form in the lines from before backwards ; the central line always differs from the others, and the teeth also vary gradually in form and size as they pass off from the central line laterally. They also vary slightly in form in different species. This lamina protrudes from the buccal body pos- teriorly, into a short, rounded, protuberant, blind sac, within which it appears to undergo a constant growth, as it is worn away by at- trition anteriorly ; for its use appears not only to facilitate the pas- sage of the food onwards to the cesophagus, but also to act as a sort of rasp for triturating it, by means of the powerful muscles composing the buccal body. Into the posterior, inferior part of the buccal body, below the blind sac of the lingual lamina, is inserted, in a transverse, curved line, its retractor muscle. This muscle has its origin, in common with the retractors of the eye-peduncles, from the muscular investment of the visceral cavity, posterior to the pulmonary cavity, and to the right of the rectum.
The cesophagus proceeds from the upper, posterior part of the buccal body backward to the stomach. It is short, and dilates gradually into the latter.
The stomach is a capacious, membranous receptacle, when extended being two thirds the length of the animal. In Z. flavus and L. agrestis, anteriorly it is dilated, and elongated-oval in form, posteriorly it is in- testiniform. In ZL. campestris, it is nearly uniformly cylindrical through- out. Where the stomach terminates in the small intestine, it makes a turn forward with the latter, producing, in Z. flavus and L. campestris,
1 See above, p. 45.
SPECIAL ANATOMY. 59
a sort of cul-de-sac posteriorly. Into the angle formed by the stomach and intestine, on each side, opens a biliary duct, which in L. agrestis, however, is more removed toward the small intestines.
The intestine forms a single convolution among the lobes of the liver, and then passes obliquely forward from the left to the right side, to
. join the rectum. It is capacious, and pretty uniformly cylindrical
throughout.
About the middle of the oblique portion going to join the rectum, in L. agrestis, opens a short, cylindrical cul-de-sac. In L. flavus the intes- tine, upon reaching the retractor muscles of the buccal body and eye- peduncles, winds around their origin, turns backward a short distance, and then again forward to the rectum, producing in this way a sigmoid flexure. From the termination of the latter in the straight portion, there proceeds backward as far as the termination of the visceral mass, a long, cylindrical cul-de-sac.
The rectum is short and straight, and penetrates into the pulmonary cavity, upon the right side of which it proceeds to the pulmonary ori- fice, at which it terminates by the anal aperture.
The salivary glands are two in number, flat, oval or irregular in out- line, of a grayish-pink hue, and are situated upon the anterior parietes of the stomach. They are composed of several lobuli, which are con- glomerated. From each gland proceeds a duct, along the cesophagus to the buccal body, into which they open on each side of the entrance of the cesophagus. In ZL. campestris the two glands are conjoined, so as to form a collar around the commencement of the stomach.
The liver, by far the largest viscus in the body, occupies a position at the posterior part of the latter. It is of a brownish color, and consists of two principal lobes, an anterior and ‘a posterior, which are further divided, the anterior into three or four, and the posterior into two lobes. Each lobe is composed of a number of lobuli held together by blood- vessels. From the convergence of branches, an hepatic duct is formed for each principal lobe, which opens in the side of the angle formed at the termination of the stomach in the intestine. The posterior cul-de- sac of the stomach usually contains some bile, which is a thin, glairy, drab-colored fluid.
Arion. The digestive apparatus offers but little peculiarity from that of imax. The retractor muscle of the buccal body is not so strong, and is divided into two lateral bands. The csophagus is narrower and longer. In the form of the stomach and absence of a cul-de-sac to
60 TERRESTRIAL AIR-BREATHING MOLLUSKS.
the small intestine, it resembles Limax campestris. The rectum, in its course to the pulmonary orifice, perforates the renal organ.
TeBenNopHorus. ‘The buccal body has a conspicuous curve down- wards, and the buccal pouch of the lingual lamina is longer than in Limax or Arion, and curves upwards from the postero-inferior part of the buccal body. The retractor muscle of the latter is split into two bands as in Arion, but one stronger. There are also two small retrac- tor muscles to the lower lip. The csophagus is comparatively long. The stomach is cylindrical and sacculated, and, posteriorly with the small intestine, forms a wide cul-de-sac. The small intestine is like that of Z. campestris and Arion. The salivary glands occupy a position on each side of the cesophagus. The ducts are tortuous.
PropHysaoN, Hempuiniia, Artotimax. In my descriptions of these genera I have included the digestive system, which has the same gen- eral arrangement as in Limaz.
It appears that no generic characters may be found in the digestive system of the respective genera, excepting the jaw and lingual mem- brane, which are treated in full in Chapter IIT.
VERONICELLA. ‘The buccal body possesses no retractor muscle. The dental plate, or jaw, is broad, and, upon the anterior surface, has a pec- tinate appearance, from the numerous ribs upon it. Its cutting edge is devoid of the conical toothlet. The cesophagus is moderately long and capacious. ‘The stomach is cylindrical and sacculated, and posteriorly forms a deep, capacious cul-de-sac, independent of the small intestine. It is strongly muscular and shining, the transverse muscular fibres being very distinct. The anterior hepatic duct opens into the angle formed by the cul-de-sac and the intestine, the posterior into the fundus of the latter. The small intestine is pretty uniformly cylindrical, and holds the usual course to near its termination in the rectum, when to reach the latter it turns abruptly backward, and joins it on the right side, just posterior to the middle of the body. The rectum is straight, and proceeds backwards, along the right side of the body, within the pulmonary cavity, and terminates between the extremity of the tail and the pedal disk, at the side of the pulmonary orifice. The salivary glands are arborescent, or fasciculated in appearance. The ducts are short and delicate. The lobuli of the liver are looser, or more sepa- rated, than in the preceding genera.
Tae Genera or Disintecrarep Heurx. The buccal body has the same appearance, generally, as in the slugs. The retractor muscle is
—S
if ® ‘ 4 .
SPECIAL ANATOMY. 61
much stronger, and has its origin in common with the retractor of the foot and eye-peduncles, from the columella of the shell; at its insertion it forms a semicircle around the posterior inferior part of the buccal body. The pouch of the lingual lamina is always a prominent object. In Zonites cellarius and Macerocyclis concava, the buccal body is propor- tionately nearly twice the length of that of the other species, denoting a carnivorous habit, as in Glandina. The dental plate, or jaw, varies in some degree in different species: in Zonites, Macrocyclis, etc. it is smooth anteriorly, and in the middle projects downwards into a large conical toothlet ; in Mesodon, T'riodopsis, etc. the anterior surface pre- sents a number of curved ribs, each of which projects Swen: as a sort of toothlet, denticulating either margin.
The cesophagus is generally long and narrow. In some species it is unusually long and contracted, as in MZ. concava, Z. cellarius, Steno- trema hirsutum, Patula perspectwa, etc. ; in others it is long, and dilated in the middle, as in Polygyra auriculata ; in many_it is capacious, and gradually passes into the stomach, as in Mesodon emoleta, etc. It is ex- ceedingly long in Polygyra septemvolva. |
The stomach is usually cylindroid, and more or less sacculated. The posterior cul-de-sac is always present.
The small intestine comes off from the stomach at a very acute angle, and into the latter two hepatic ducts empty. It is pretty uniformly cylindrical, and forms, as in slugs, a single convolution or a sigmoid curve, among the lobes of the liver, and penetrates to the pulmonary cavity at its right posterior angle. The rectum, in all the testaceous genera, corresponds in length to the pulmonary cavity, the right side of which it occupies to the pulmonary orifice, at the outer border of which it terminates by the anal aperture. It is cylindrical, usually wider than the small intestine, and is frequently somewhat sacculated. Upon the outer side of the rectum, running its whole length, is a band of muscular fibres, the object of which is, apparently, the retraction of the collar, the shortening of the rectum, and the expulsion of its con- tents.
The salivary glands are generally elongated, oval, with lobed edges. They are usually united together and situated on the cesophagus, or commencement of the stomach. When the wsophagus is narrow they surround it; when dilated, they occupy one half or two thirds of its surface. The salivary ducts are long and large.
The liver is four-lobed, three of which lobes are anterior or inferior,
62 TERRESTRIAL AIR-BREATHING MOLLUSKS.
and the fourth posterior or superior. The fourth lobe, conjoined with the testicle, forms the very summit of the turbinated mass. The ducts from the anterior lobes converge to form a single trunk, which, with that from the posterior lobe, open into the junction, or angle, of the cul-de-sac of the stomach with the intestine.
Binneya. The cesophagus is very short; the stomach very wide, short.
Buuimutus. The digestive apparatus in B. dealbatus and B. multi- lineatus resembles that of Polygyra auriculata ; the esophagus is long, narrow, and dilated in the middle; the stomach is cylindroid, and more or less sacculated.
Stenocyra. The digestive system is like the last.
Lieuus. The stomach of Liguus fasciatus resembles that of Limax jlavus, being large and capacious anteriorly, cylindrical and sacculated posteriorly. The rectum is:capacious and sacculated.
OrrHaticus. The digestive system of wndatus is as in Liguus. It does not essentially differ from that of the genera of disintegrated Helvx.
Pura. A characteristic of this genus is the very great proportionate length of the viscera, corresponding to the numerous whorls of the shell. The retractor muscle of the buccal mass is long and strong. The csophagus is very long and narrow. The stomach is very long, and even forms a fold upon itself. The rectum is very long and saccu- lated ; the muscle on its outer side is well developed.
Sucoinea. A characteristic of this genus, the reverse of Pupa, is the great breadth and shortness of the viscera. The dental plate, or jaw, has an upper quadrangular piece, superadded to the ordinary crescen- tic plate. The stomach resembles that of Zimax jlavus. Its mucous membrane presents several longitudinal ruge. The small intestine does not undergo the same relative diminution with the other viscera. The rectum is very short, and, from the transverse position of the pul- monary cavity, it is placed along the right of the breadth, instead of the length of the latter, as usual. The salivary glands are situated one on each side of the commencement of the stomach; their ducts, just before opening into the buccal body, become dilated.
Macrocycuis. The buccal mass, as stated above, is twice the size of that of the other genera.
Guanpina. The oral orifice is triangular, and bounded by three papillated lips, one upper and two lateral. The buccal body is a very
; é .
SPECIAL ANATOMY. 63
long muscular cylinder, a little curved downward at the posterior part. There is no cul-de-sac for the lingual lamina protruding behind ; and the retractor muscle is divided into three fasciculi, one central and pass- ing into the buccal body posteriorly, the others lateral and inserted as usual. Externally, it has a very thin investment of longitudinal mus- cular fibres, continuous with those of the retractor muscle and the ori- gin of the especial muscles of the tongue. This layer is very delicate and transparent ; and at the anterior third of the buccal body, laterally and inferiorly, it presents several fasciculi, which pass to the tegumen- tary lips. Beneath the exterior covering, and readily seen through it, is a thick and strongly fasciculated, transverse layer of muscular fibres. When the buccal body is laid open the oral orifice is found to be con- tinuous with a triangular canal with smooth sides, running one third its length. At the posterior superior termination of the canal is the open- ing of the csophagus and orifices of the salivary ducts. There is no dental plate, or jaw. The posterior two-thirds of the buccal body is occupied by a long oval organ, composed of numerous, strong fasciculi of muscular fibres, arising laterally and inferiorly at the posterior part of the buccal body; the former passing inwards and forwards, the latter forwards to the anterior extremity of the organ, which is free, and pro- jects into the triangular, oval canal. The lateral fasciculi leave between them superiorly an interstice, at the bottom of which is found the lin- gual membrane, in the form of a tube, closed posteriorly, and open and reflected downwards and backwards upon the anterior, free tip of the organ. Into the posterior extremity of the lamina the middle fascicu- lus of the retractor muscle of the buccal body is inserted; and, just anterior to this insertion, a small, attrahent fasciculus, arising from the roof of the buccal body, posterior to the orifice of the cesophagus, which gets to the lamina by means of the interstice of the muscular organ superiorly. The teeth of the lingual membrane are arranged diagonally, from the middle line, in parallel rows, passing from within outwards, as shown in the descriptive portion of this work.
The cesophagus issues from a fissure at the upper posterior line of the anterior third of the buccal body. It is long and cylindrical, and rather wider at its termination than at its origin. The stomach is irregularly cylindroid, and has a cul-de-sac at its commencement, pro- jecting anterior to the entrance of the esophagus. The small intestine is capacious.
The salivary glands are conjoined, so as to form a circular collar
64 TERRESTRIAL AIR-BREATHING MOLLUSKS.
around the posterior part of the wsophagus. The salivary ducts are long, and enter the same fissure of the buccal body at which the cesoph- agus issues. ‘I'he anterior lobes of the liver are comparatively very small, while the posterior lobe is correspondingly large; and to the whole there is but a single duct.
OBSERVATIONS ON THE TISSUES OF THE DIGESTIVE APPARATUS,
The mucous membrane of the alimentary canal is usually smooth throughout. In the stomach it frequently presents a number of trans- verse folds, corresponding to the contractions which produce the saceu- lated appearance of the organ ; and in several species of different genera it presents a few longitudinal rugz, as in Limax flavus, Liguus faser- atus, Mesodon exoleta, etc. In its whole extent it is formed of a colum- nar epithelium and a nucleolated-nucleated basement membrane. The columnar cells of the epithelium are long and pyramidal, the upper part or base being broad, and the attached extremity very narrow. They are filled with a very fine, indistinct, granular matter, inter- mingled with coarser, highly reflective granules. Each contains an oval, granular nucleus, with a minute nucleolus.
The muscular investment of the intestinal canal is strongest upon the stomach and rectum. In Veronicella, Strophia wmcana, ete. it is strong and shining upon the stomach. It consists of two layers, an internal transverse and an external longitudinal. They are both com- posed of white, shining, strap-shaped bands, with the extremities pointed and closely adapted to each other. None of the transverse bands surround the stomach, all being much too short. ‘They are in- distinctly granular in structure, and each contains one or two elongated nuclei.
The lobules of the salivary gland are composed of the dilated com- mencements of the ducts, lined with soft, glanular cells, which are oval in form, and contain a round, granular nucleus with a minute nucleolus. The basement membrane of the salivary ducts is amorphous. The epi- thelial cells lining the trunks bear considerable resemblance to those found in their follicular commencement. Outside of the basement
membrane, twine narrow muscular fibres in various directions. They
are nucleated, and where the nuclei exist are wider than at the inter- vening parts. .
The lobuli of the liver are composed of the rounded commencement of the biliary ducts, and are lined with polygonal cells, which become
SPECIAL ANATOMY. 65
globular on the removal of pressure. The hepatic cells contain a fine, granular matter, fine and large oil-globules, and a round, nucleolated nucleus.
Or THE GENERATIVE APPARATUS.
All the terrestrial Gasteropoda under consideration are monoecious or hermaphroditic, though none are capable of self-impregnation. They are also mostly oviparous.
Their genital system is complicated, and liable to such variation in its details as to furnish excellent generic and specific characters. I have therefore, when possible, given descriptions of the system in the descriptive portion of my work, under each species. I will here give only a general description of the development of the system : — The tes- ticle is a single globular mass of aciniform cceca in some genera; in others it is composed of numerous fasciculi of long caca: it is free, or imbedded in the upper lobe of the liver; its position, as well as the shape of its cceca, being different in the respective genera.
The epididymis is an undulated, or moderately tortuous tube, lead- ing from the testicle to the inner side of the junction of the ovary with the prostate gland. It opens into a groove upon the inner side of the interior of the oviduct, which is continuous, at its inferior extremity, with the vas deferens. Opening into the termination of the epididy- mis, and lying against the inner side of the ovary, is a small, compound, follicular body, which appears to be common to all the terrestrial Gas- teropoda, and is known as the accessory gland of the epididymis. The prostate gland is a white or cream-colored body, occupying the inner side of the whole length of the oviduct. It has a transverse, striated appearance, and numerous openings into the groove leading from the epididymis to the vas deferens.
The vas deferens is a comparatively short tube, passing from the prostate gland to the penis sac. The position of its junction forms a specific character; sometimes it joins the summit of the latter, at others it enters near the base.
The penis sac is generally a long, cylindroid, irregular body, lying at the right anterior part of the visceral cavity, and joining at its termina- tion a short cloaca. Its form is, however, very variable, and is an ex- cellent specific character, as is also the point of insertion of the retractor muscle, which has its origin from the muscular investment of the vis- ceral cavity, just posterior to the position of the pulmonary cavity. The penis sac often has a flagellate appendage containing the curious
66 TERRESTRIAL AIR-BREATHING MOLLUSKS.
organ known as the capreolus. The above are the male organs of the compound system. :
The female organs consist of the ovary, a linguiform body, sometimes lobulated, at the posterior end of the genital system. The oviduct is a long sac-like body, usually greatly convoluted in its course. It de- creases in breadth at its anterior end, and gradually merges into the vagina, a long tube-like body of uniform size to the common external orifice ; into its lower end, called by Dr. Leidy the cloaca, enters the penis sac, and above this enters also the duct of the genital bladder. This last organ, as well as the bladder itself, varies greatly in size and length, and forms an excellent specific character.
The above is the simplest form of the genital system, all these organs being absolutely necessary. It is often much more complicated by having an accessory, very much lengthened duct to the duct of the gen- ital bladder, by various forms of vaginal prostate glands, often with complicated accessories; with one or more dart sacs entering into the vagina, containing a dart of various shape. The penis sac also some- times has curious and varied accessories. All these organs may be found in some species of any given genus, while other species may have only the organs necessary to the genital system.’ I am induced, there- fore, to consider the details of the generative system to be only a spe- cific character. As a generic character we can rely only on the position of the external orifice of the system, and on the position of the testicle as well as the form of the ceca which compose it. Thus Glandina, Zonites, and Ariolimazx have the external orifice under the mantle, while usually it is found behind the right eye-peduncle. Again imax, Arvo- limax, Prophysaon, Hemphillia, Arion, Glandina, and Succinea have the testicle free, and formed of aciniform coeca, while in the genera of dis- integrated Helix and others it is composed of fasciculi of elongated ceca commingled with the substance of the upper lobe of the liver.
GENERAL REMARKS UPON THE JUNCTION OF DIFFERENT PORTIONS OF THE GENERATIVE APPARATUS, AND THE STRUCTURE OF ITS TISSUES.
The testicle was mistaken by Swammerdam, Cuvier, and others for the ovary, and the latter organ and prostate gland for two portions of the testicle. A microscopic examination of these different organs at
1 For instance, in Arionta we find the necessary organs only in Townsendiana, but in Nicklinianaand other species a great variety cf accessory complications.
a a tet
SPECIAL ANATOMY. 67
once very easily settles their true nature; although, even without this mode of analysis, we would suppose the epididymis would indicate the character of the gland of which it is the duct, and leave the remain- ing two organs to be considered as belonging to the female apparatus. In Helix the structure of the testicle consists of dense fasciculi of short coecal pouches, which are simple, bifurcate, or trifurcate. These contain polygonal spermatophori, which are finely granular with a round nucleus, or filled with granular globules of uniform size, or with coils or bunches or fasciculi of spermatozoa. The epididymis always contains, more or less, and is frequently distended with, a white, silky, filamen- tous substance, composed of spermatozoa. The latter consist of very deli- cate and, comparatively, enormously long filaments, terminating, at one extremity, ina thickened head. They vary in length in different spe- cies of these gasteropods. The head assumes two principal forms ; it is either sigmoid and pointed, as in Mesodon albolabris, Mesodon multili- neata, etc., or else it is spiral and pointed, as in Patula alternata, Pa- tula solitarza, etc. In the vas deferens the spermatozoa may often be detected in movement, which is slow and vibrating in character.
The prostate gland, although situated along the tract of the oviduct, evidently belongs to the male apparatus, as is proved by its emptying solely into the vas deferens in Veronicella, and in its being placed be- tween the termination of the epididymis and the commencement of the vas deferens only, as is very conspicuously observed in Succinea. In structure, it is composed of closely packed, tortuous, tubular, simple follicles, lined with short, thick, pyramidal epithelia, which are densely granular, and contain a round, nucleolated nucleus. -The object of this organ probably is to dilute the very tenacious spermatic matter as it oozes from the epididymis into the spermatic groove on the inner side of the oviduct.
In all the terrestrial gasteropods examined, there was found a small glandular body, from which proceeds a short duct to join the termina- tion of the epididymis. It consists of from two to nine rounded folli- cles joining a common duct, and, from the constancy of its existence, must be deemed important.
The ovary is soft and homogeneous in appearance; viewed by the microscope, it is found to be almost wholly composed of immature ova, polygonal cells with a germinal vesicle and macula.
The sides of the oviduct are soft, and in great measure composed of a tissue consisting of large polygonal cells, with from one to five small round nuclei.
68 TERRESTRIAL AIR-BREATHING MOLLUSKS,
The organ denominated genital bladder, from its opening into the vagina, or at the termination of the latter, and in Veronicella from its belonging almost wholly to the female organs, must be considered rather as a portion of the female apparatus than a prostatic sac, as it is called by Owen. By many authors this has been termed the spermatheca, from its supposed function of holding spermatic fluid received from the male organs, and with some reason; for in several instances I have found it to contain a tenacious mass, which upon microscopic analysis was found to be composed of spermatozoa. This cannot, however, be considered wholly as its use; for it secretes a mucoid matter, which may probably facilitate the passage of the ova through the vagina and cloaca. ‘The mucoid matter within the bladder is frequently found to contain immense numbers of an infusorial parasite, which has been de- scribed under the name of Cryptoicus.?
The epithelium of the bladder consists of very long, caudate, colum- nar cells, with elliptical, granular nuclei, and a small round nucleolus.
In comparison of the descriptions of genitalia in this work with those given by foreign authors, it must be remembered that the terms ovary, testicle, etc., are not applied to the same organ.
In Vol. I. will be found figures of the genital system of many ot our species. I have in this volume repeated the descriptions, under each species, and given figures of many not included in the plates of Vol. I.
Or THE RESPIRATORY AND CIRCULATORY APPARATUS.
The lung of the Terrestrial Gasteropoda is a simple cavity, with an orifice communicating with the exterior, upon the right side of the body. The surface of this pulmonary cavity in part of its extent, and more particularly near the pulmonary orifice, is covered by a close in- tertexture of blood-vessels. The blood of the body is conveyed directly to the lungs by two principal vessels, the pulmonary arteries, which join the capillary rete of the pulmonary surface. From this rete passes off the pulmonary vein to the heart, which is systemic, and consists of an auricle and ventricle. The auricle receives the pulmonary vein ; from the ventricle passes off the aorta, to be distributed throughout the body.
Limax. The pulmonary cavity is situated beneath the mantle, and has nearly the same size and form. It is separated from the visceral cavity by the muscular peritoneum, but contains the rectum, renal
1 Journ. Acad. Nat. Sci. Phila. N. S. Vol. I.
an
SPECIAL ANATOMY. 69
organ, and heart. The pulmonary orifice is situated at the antero-infe- rior edge of the mantle, on the right side of the body. When open it appears round ; it is closed by means of circular muscular fibres. The pulmonary rete is principally displayed upon the roof of the cavity, and from it converge three principal trunks, to form the pulmonary vein which passes to the auricle of the heart.
The heart, enclosed within a pericardium, is situated near the middle of the pulmonary cavity. The auricle and ventricle are pyri- form, and placed base to base. The sides of the latter are consider- ably thicker than those of the former, and present internally several well-marked fasciculi, crossing in different directions. Between the auri- cle and ventricle is a double valve. From the apex of the ventricle passes off the aorta, which pierces the muscular peritoneum, and divides into two principal branches, — one passing to the sub-cesophageal gan- glia devoted to the viscera in the anterior part of the visceral cavity, the other passing to supply the viscera posteriorly. Upon the right of the heart, attached to the roof of the pulmonary cavity, is placed a large glandular organ, considered as the kidney ; from the whole of its right margin proceeds a duct backwards, which then curves to the side of the rectum, at the left side of whichit remains attached to the pulmonary orifice.
Arion. The pulmonary cavity is situated as in imax. Its whole interior surface presents an intricate rete, from which converge six or seven pulmonary veins to the auricle of the heart.
The renal organ forms a complete circle around the heart, and is per- forated by the rectum, in the course of the latter to the pulmonary aperture.
TEBENNOPHORUS. ‘The pulmonary cavity is situated beneath the an- terior portion of the mantle. It is formed by an inflection of the mus- cular layer of the integument of the body. The renal organ is placed to the right of the heart, and at its posterior part is perforated by the aorta.
VERONICELLA. The pulmonary cavity is situated between the mus- cular peritoneum and the integument of the body. Its principal por- tion is placed upon the right side, anterior to the middle, but extends to the left side, over the back, and along the right side to the pulmo- nary aperture, between the tail and posterior extremity of the podal disk. The heart is placed in the anterior portion of the cavity. The auricle receives a vein from the right and another from the left side.
70 TERRESTRIAL AIR-BREATHING MOLLUSKS.
The renal organ is placed posterior to the heart, between the passage leading from the pulmonary cavity to its orifice, and the course of the rectum.
Tue GeNnERA OF DISINTEGRATED Hexix. In this genus, as is also the case in all the testaceous genera under examination, the pulmonary chamber is comparatively very large, for reasons already stated, and occupies a position on the outside of the lower one or two whorls of the turbinated mass of the viscera. In front, it is bounded by the collar, in the right side of which is the pulmonary orifice. The floor of the cavity is formed, as in slugs generally, by the muscular peritoneum. The roof, or outer wall, is occupied on the right side by the rectum, posteriorly by the heart and renal organ, and anteriorly by the pulmo- nary rete of capillary vessels. 'The pulmonary rete is most developed in the vicinity of the pulmonary orifice ; and from it in a line with the latter, along the course of the rectum, proceeds backward a single pul- monary vein to the heart. The renal organ is elongated, pyramidal, and is placed to the right of the heart and pulmonary vein. Its duct commences upon the right border of the gland, courses backward to the rectum, along the inner side of which it passes to the pulmonary aperture.
The remaining testaceous genera present nothing peculiar in the character of the pulmonary or circulatory apparatus.
GeneRAL Remarks. The heart, in warm weather, beats about fifty-five times in a minute, but to some extent appears to be under the control of the animal, for if disturbed or irritated it pulsates much slower.
In composition, the heart consists of distinctly granulated, unstriped muscular fibres, with oval nuclei, which are hardly visible before the application of acetic acid to them.
The interior of the heart and aorta is lined with a tessellated epithe- lium ; and the exterior of the former and interior surface of the pericar- dium are covered by the same. The cells are granular, with distinct, round, or oval, granular nuclei, and a minute nucleolus.
The pericardial epithelium separates its peculiar fluid very freely, the pericardium frequently appearing distended with the liquor pericardii. In the testaceous genera it frequently contains numbers of an entozoon, which Dr. Leidy has named Distoma vagans.' The blood-vessels, espe- cially in the liver, exhibit a white opaque appearance, which is depen- dent upon the deposit in the sides of the vessel of innumerable, oil-like
granules. 1 See Journal Acad. Nat. Sci. Phila., New Series, Vol. I.
SPECIAL ANATOMY. (gp
The blood contains numerous blood-corpuscles, which vary in size, are granular, and exhibit numerous radiating, projecting points of variable length, — frequently greater than the diameter of the corpuscle.
The pulmonary cavity is lined with a tessellated epithelium, the cells of which are faintly granular, with a few coarser granules, and a distinct, round or oval, granular, nucleolated nucleus.
The renal organ is a gland which exhibits a foliated or plicated ap- pearance, within a capsule. The surfaces of the plice communicate with the duct existing along the whole right border of the organ, and are covered with polygonal, organic cells, every one of which contains a large, white, round, opaque mass, resembling uric acid in appearance.
On THE Nervous CENTRES, AND THE DISTRIBUTION OF THE NERVES.
The nervous centres consist of three distinct sets of ganglia, which are all placed within the anterior part of the body or head.
The first set, or supra-cesophageal ganglia, form a transverse band, above or in front of the buccal body, usually at its anterior part, but varying in the latter position, to some degree depending upon the movements of the buccal body. When the latter is protruded, the band of ganglia is thrown back to the commencement of the cesophagus ; when retracted, it is placed just behind the upper lip. It consists of two symmetrical halves united by a short transverse commissure. Each half is composed of several ganglia, aggregated to a greater or less de- gree in different genera and species. Sometimes they are so aggregated, or are so covered by enveloping tissue, as to appear a single mass ; in others five or six distinct masses may be readily counted.
The second set, or sub-cesophageal ganglia, form a circular mass, placed infero-posteriorly to the buccal body, in the excavation of the foot. It is asymmetrical, and is composed of several ganglia, more or less aggregated together ; from four to seven masses can generally be counted. It is usually more developed upon the right than the left side, and passes through all the shades of color, in different genera and species, from white and yellow to orange. ‘Through the opening formed by the arrangement of the ganglia into a circle passes the cephalic branch of the aorta. The supra-cesophageal and sub-cesophageal ganglia are connected together on each side of the buccal body by a double commissure, which varies in length in different genera ; thus, in Helices, etc., it is generally so long as to allow of much movement of the supra- cesophageal ganglia forward with the buccal body, while in Veronicella
72 TERRESTRIAL AIR-BREATHING MOLLUSKS.
it is so short that the two sets of ganglia form a close ring around the anterior part of the buccal body.
The third set of ganglia are the stomato-gastric, consisting of two minute lateral masses, united by a short transverse commissure, and always placed upon the buccal body immediately postero-laterally to the commencement of the esophagus. The stomato-gastric ganglia are connected with the supra-cesophageal on each side, by means of a long, delicate commissure, which is more or less loose, and permits a free movement of the former ganglia with the buccal body to which they are fixed.
From the supra-cesophageal ganglia pass off on each side, — Ist, a minute branch along the course of the supra-sub-cesophageal commis- sure; 2d, three or four small branches to the retractor muscles of the eye-peduncles ; 3d, a large branch, the superior tentacular nerve ; 4th, one or two small branches to the base of the eye-peduncle, for its integ- ument ; 5th, the inferior tentacular nerve ; 6th, small branches to the integument of the lips.
From the sub-esophageal ganglia pass off, — lst, numerous branches on each side, to the podal disk, and laterally to the integument ; 2d, a branch on the right side to the penis; 3d, a branch to the vas deferens and prostate gland; 4th, on each side a branch to the retractor muscle of the buccal body ; 5th, a large one to each side of the collar and pulmo- nary chamber; 6th, a branch which follows the posterior aortic vessel, which gives off branches to the muscular peritoneum ; 7th, branches to the origin of the tentacular retractors; 8th, branches to the oviduct, ovary, testicle, stomach, intestine, and liver.
From the stomato-gastric ganglia pass off on each side, — Ist, a nerve to the external muscular structure of the buccal body ; 2d, two branches which penetrate posteriorly into the buccal body ; 3d, a branch to the salivary duct and gland; 4th, a branch to the cesophagus and stomach ; 5th, branch to the interior of the buccal body anteriorly.
The above distribution of the nerves has been principally derived from dissections of Glandina and Mesodon albolabris. In the former genus, upon what is the nerve to the tentacle in the other genera, there is formed, near the base of the eye-peduncles, a ganglionary enlargement, from which passes off the true, inferior tentacular nerve of this animal, and two other large branches to the third, or external tentacle.
The nervous centres are composed of ganglion globules, varying very much in size ; some are very large, others are not more than one eighth
SPECIAL ANATOMY. 73
the diameter of the larger ones and nuclear bodies. The globules are more or less polygonal, from mutual pressure, are distinctly granular, and contain a nucleus which is comparatively of enormous size. The latter usually fills one half or two thirds of the cell or globule, is more distinctly and darkly granular, and contains from one to seven small, round, transparent nucleoli. The separate nuclear bodies resemble the nuclei of the ganglion globules, but are much smaller, and contain but a single nucleolus. The nerve-fibres pass through the ganglionary centres, among the globules in every direction; but none of them ap- pear to originate or terminate in the latter. None of the ganglionary cells are caudated.
The nerves consist of bundles of tubuli, containing an oleo-albumi- nous matter, which in the fresh nerve is semi-fluid, faintly granular, homogeneous, and translucent, but after the matter is pressed out of the tubuli it separates into two portions, one of which is a tenacious, fluid substance, containing the other in the form of oil-like globules of no determinate size. The wall of the tubuli is amorphous and trans- parent, and has attached to it, and projecting externally, oval, granular nucleolated nuclei.
The nerves, especially in those emanating from the supra-cesophageal ganglia, are enveloped in a sheath formed of large, elongated, polygonal, transparent cells, containing in the centre an oval nucleus surrounded by a mass of coarse granular bodies, which are endowed with a very active molecular movement.
ON THE ORGANS OF ESPECIAL SENSE.
* Tovuca. The soft, mucous integument is very irritable; but tactile sensibility is most developed in the tentacula and eye-peduncles, which are two pairs of tubular prolongations of the external integument, from the anterior part of the body or head. The superior pair, or eye-pedun- cles, are several times longer and thicker than the inferior pair. They are conico-cylindroid in shape, with the free extremity or point dilated, or bulbous, in the outer side of which the eyes are placed. The infe- rior pair, or tentacula, are short, conico-cylindroid, and slightly bulbous at the point.
The integument is thick at the base of the tentacula, but gradually becomes thinner as it approaches the free extremity, where it is deli- cate and transparent. The color is the same on the general investment of the body, except at the free extremity of the tentacula, where, from
~
74 TERRESTRIAL AIR-BREATHING MOLLUSKS.
its transparency, the structure beneath shows through, and appears whitish. On the eye-peduncles it is rougher than upon the tentacula, from the polygonal folds being deeper. It is but loosely attached to the parts within, except at the free extremity, where it becomes firmly united,
The retraction of the eye-peduncles takes place by means of the con- traction of the retractor muscle, which forms within them a cylindrical tube, and is inserted into the integument at their free extremity, so that when they are retracting the integument becomes inverted, and the point of the eye-peduncle first disappears from view and, in protru- sion, is last to appear. The latter movement takes place through the relaxation of the retractor muscle, and the gradual contraction of the circular muscular fibres forming the basis of the integument, commen- cing at the base of the eye-peduncle and proceeding towards the free extremity, by which course of movement the latter is pushed out.
Within the tube of the retractor muscle of the eye-peduncles, passes to the free extremity of the latter the tentacular nerve. When the eye- peduncles are retracted, the nerve becomes tortuous and spiral, but when fully protruded it is nearly straight or merely undulated.
Near the free extremity of the eye-peduncles, the nerve undergoes a sudden constriction, and then dilates into a gangliform enlargement, from the outer side of which proceeds a small division of the tentacular nerve, as the optic nerve, to the eye. The gangliform enlargement is composed, on the exterior, of the nerve-tubuli of the tentacular nerve, and on the exterior, of a soft, white, finely granular matter, containing, in the exterior layer, round, granular, nuclear bodies. Anteriorly, the enlargement undergoes a constriction, and then dilates into the large bulbous mass of the extremity of the eye-peduncles. This latter mass is white, soft, and finely granular. Upon its exterior the nerve-tubuli of the exterior of the first gangliform enlargement diverge, and divide into a number of large branches, which laterally subdivide into numer- ous smaller branches, and thus enclose the granular mass.
The tentacula present the same nervous structure, except that there is no well-marked constriction between the tentacular nerve and the first gangliform enlargement, nor between the two enlargements, nor is there any optic nerve.
The space between the tentacular nerve and the retractor muscle is filled with a filamentous tissue, containing round, granular, nucleolated nuclei, and large, round or elliptical, transparent cells, with nuclei sim- ilar to those which lie free in the tissue.
ini rte
SPECIAL ANATOMY. 75
The integument of the eye-peduncles is very freely supplied with nerves from the supra-osophageal ganglia.
Tasty, If existent, it is probably dependent upon nerves distributed within the buccal body, and derived from the stomato-gastric ganglia. The structure of the lingual membrane precludes any idea of its exist- ence there.
Smet. The presence of this sense is undoubted, though there is much discrepancy of opinion as to its situation. I have suspected that it probably may be placed in the blind sac, or depression, which opens just below the mouth. This sac varies in its degree of development in the different genera: in Zimax it is a superficial depression ; in Vagi- nulus it extends backwards beneath the buccal body for half an inch, is conical in shape and yellowish-white in color; in Liguus fasciatus it extends back, in the excavation of the foot, to the tail, and is folded several times upon itself.
Hearina. The acoustic apparatus consists of a pair of transparent vesicular bodies, placed upon the postero-inferior part of the sub-cesopha- geal ganglia, one on each side. They are placed in a depression of the ganglia formed by a separation of the nerve-tubuli as they pass from and into the latter, immediately upon the ganglionic globules. Their interior is filled with a transparent fluid, containing numerous otoco- nites, which vary in size, are oval in form, transparent, composed of con- centric layers of carbonate of lime, and frequently have a small cavity in their centre. During life, and for a short time after the death of the animal, the otoconites are endowed with a peculiar vibratory move- ment, by which they are disposed to accumulate into a mass in the centre of the auditory vesicle. After the cessation of the movement they become diffused through the fluid of the vesicle.
Sicut. The eyeball is placed beneath the integument, on the outer side of the constriction which exists between the gangliform swellings at the free extremity of the eye-peduncles. The optic nerve is derived from the inferior part of the first gangliform enlargement, is tortuous or undulating, and reaches the eyeball at its posterior part. Its course is frequently indicated by a deposit of pigmentum nigrum.
The eyeball is globular, and is invested exteriorly by a transparent tunic, corresponding to the sclerotica and cornea,
The choroidea forms two thirds of a sphere, and is inflected anteriorly into a sort of depressed disk, perforated in the centre. It consists of a delicate, translucent membrane, with a deposit of a single layer of irreg-
76 TERRESTRIAL AIR-BREATHING MOLLUSKS.
ularly rounded, or oval, black pigment cells. The interior of the cho- roidea contains a clear, consistent vitreous humor; but the character of the retina I did not detect at the time. Whether a crystalline lens ex- ists or not I am in doubt; at the time of making the investigations, in several instances I thought I discerned it very distinctly ; but in other instances, even when larger species were examined, if it existed it es- caped my observation.
V. CLASSIFICATION.
WiTHoUT suggesting any system of classification, I have already ex- plained (p. 47) that in the descriptive portion of this work I have grouped the genera into families according to the character of the jaw and lingual membrane. I am too well aware that such an arrangement separates genera nearly allied by other, perhaps more important, characters,’ but the same objection may be made to any system thus far proposed.
The characters on which generic distinction is founded are more satis- factory. These are, the external form of the animal, whether slug-like, as in Zimaz, or snail-like, as in Helix ; the position of the mantle, anterior, central, or posterior, whether naked, enclosing some form of internal shell, or protected by an external more or less developed shell ; the presence or absence of longitudinal furrows above the margin of the foot, meet- ing over a caudal mucus pore; the presence or absence of a distinct locomotive disk to the foot ; the position of the external respiratory and generative orifices ; finally, by the absence or presence and character of the jaw, and the character of the lingual dentition.
When a genus is numerous in species I have, for the sake of conven- ience, adopted sections or subgenera, founded on special features of the shell, such as the absence or presence of internal lamine or tooth-like processes within the aperture.
In treating the species I have recognized a wide range of variation rather than distinct specific weight in the differences one observes among numerous individuals.
Guided by these rules, I have grouped our species in the manner shown in the synopsis in Chapter VI.
1 Thus Veronicella is placed in Holognatha, though it widely differs from the other genera of that family in having contractile, not retractile eye-peduncles, and still more by having separate orifices for the male and female organs of generation. Again Onchidella from the character of its jaw is classed with Patwla, etc., though it most widely differs from all the Geophila in having no tentacles, and though its genital system is like Veronscella.
oa
SYSTEMATIC INDEX.
VI. SYSTEMATIO INDEX. PULMONATA GEOPHILA.
Glandina Vanuxemensis, Lea.
truncata, Gel. decussata, Desh.
AGNATHA.
Glandina bullata, Gid. Texasiana, P/r.
HOLOGNATHA VITRINEA.
sportella, Gid. concava, Say. Voyana, Newc. Duranti, Newc.
Zonites Mesomphiz.
capnodes, W. G. B. fuliginosus, Griff. friabilis, W. G. B. caducus, P/r. levigatus, Pfr. demissus, Binn. ligerus, Say. intertextus, Binn. subplanus, Linn. inornatus, Say. sculptilis, Bland. Elliotti, Redf. cerinoideus, Anth. Ayalinia. cellarius, Miill. Whitneyi, Newc. nitidus, Miill. arboreus, Say. viridulus, Mke. indentatus, Say. limatulus, Ward. minusculus, Binn. milium, Morse. Binneyanus, Morse.
Macrocyclis Vancouverensis, Lea. Zonites ferreus, Morse.
conspectus, Bland. exiguus, Stimpson. chersinellus, Dall. capsella, Gid. placentula, Shuttl. Conulus. fulvus, Drap. Fabricii, Beck. Gundlachi, P/r. Stearnsi, Bi. Gastrodoenta. gularis, Say. suppressus, Say. lasmodon, Piillips. significans, Bland. internus, Say. multidentatus, Binn.
Vitrina latissima, Lewis.
limpida, Gould. Angelice, Beck. Pfeifferi, Newc.
exilis, Mor.
Limax maximus, Lin. flavus, Lin. agrestis, Mill. campestris, Binn.
Hewstoni, J. G. Cooper.
montanus, /ng.
HOLOGNATHA HELICEA.
*
Patula solitaria, Say.
strigosa, Gid. Hemphilli, Newe. Idahoensis, New. Haydeni, Gabb. alternata, Say. Cumberlandiana, Lea. perspectiva, Say.
Patula striatella, Anth. pauper, Mor. Horni, Gabb. asteriscus, Morse. Microphysa incrustata, P/r. vortex, Pfr. Lansingi, Bland. Ingersolli, Bland. Hemitrochus varians, Mike.
77
78 TERRESTRIAL AIR-BREATHING MOLLUSKS.
Holospira Roemeri, P/-. Goldfussi, P/r. Onchidella borealis, Dall. Tebennophorus Caroliniensis, Bosc. Helicodiscus lineatus, Say. Ferussacia subcylindrica, L, Cecilianella acicula, Mill. Stenogyra Rumina. decollata, Z, Opeas. subula, Ps. octonoides, Ad. Melaniella. gracillima, Pfr. Pupa Pupilla. muscorum, L. Blandi, Morse. Hoppii, Miill. variolosa, Cid. pentodon, Say. decora, Gid. corpulenta, Morse. Rowelli, Newc. Californica, Rowell. Leucochila, fallax, Say. modica, Gid. Arizonensis, Gadd. hordeacea, Gabdb. armifera, Say. contracta, Say. rupicola, Say. corticaria, Say. pellucida, P/r. borealis, Mor. alticola, Ing. Vertigo Gouldi, Binn.
. Bollesiana, Morse. milium, Gid. ovata, Say. ventricosa, Morse. simplex, Gid.
Strophia incana, Binn.
* * Arion fuscus, Miill, foliolatus, Gid.
Ariolimax Columbianus, Gid. Californicus, J. G. Coop. niger, J. G. Coop. Hemphilli.
Andersoni.
Prophysaon Hemphilli, B/. g Binn. Veronicella Floridana, PBinn. olivacea, Stearns. Binneya notabilis, J. G. Coop. Hemphillia glandulosa, Bl. ¢ Binn. Pallifera dorsalis, Binn. Wetherbyi, W. G. Binn. Strobila labyrinthica, Say. Hubbardi, Brown. Gonostoma Yatesi, J. G. Coop. Polygyra auriculata, Say. uvulifera, SAuitl. auriformis, Bid. Postelliana, Bid. espiloca, Rav. avara, Say. ventrosula, P/r. Hindsi, Pfr. Texasiana, Moricand. triodontoides, Bid. Mooreana, W. G. Binn, hippocrepis, P/. fastigans, L. W. Say. Jacksoni, Bid. Troostiana, Lea. Hazardi, Ald. oppilata, Moricand. Dorfeuilliana, Lea. Ariadne, Pfr. septemvolva, Say. cereolus, Muhif. Carpenteriana, Bid. Febigeri, Bid. pustula, Fer. pustuloides, Bld. leporina, Gid. [ Coop. ’Polygyrella polygyrella, Bid. §& J. G. Stenotrema spinosum, ea. labrosum, Bid. Edgarianum, Lea. Edvardsi, Aid. barbigerum, Redf. stenotremum, Fé. hirsutum, Say. maxillatum, Gid. monodon, Rack. germanum, Gid. Triodopsis palliata, Say. obstricta, Say. appressa, Say. inflecta, Say.
BP an
SYSTEMATIC INDEX.
Triodopsis Rugeli, Shuttl.
tridentata, Say.
Aglaja infumata, Gid. Hillebrandi, Newe.
Harfordiana, J. G. Coop. Arionta arrosa, Gid.
fallax, Say. introferens, Bld.
Hopetonensis, Shuttl.
Van Nostrandi, Bid. vultuosa, Gid. loricata, Gid.
Mesodon major, Binn.
albolabris, Say. divesta, Gid. multilineata, Say. Pennsylvanica, Green. Mitchelliana, Lea.
Townsendiana, Lea. tudiculata, Binn. Nickliniana, Lea. Ayresiana, Newc. redimita, W. G. Binn. intercisa, W. G. Binn. Kelletti, Fbs. Stearnsiana, Gabb. exarata, Pfr. ramentosa, Gid. Californiensis, Lea.
79
elevata, Say. Clarki, Lea. Christyi, Bld. exoleta, Binn. Wheatleyi, Bid. dentifera, Binn. Roemeri, P/r. Wetherbyi, Bid. thyroides, Say. clausa, Say.
Columbiana, Lea.
Downieana, Bid. Lawi, Lewis. jejuna, Say. Mobiliana, Lea. devia, Gid. profunda, Say. Sayii, Binn. Acanthinula harpa, Say. Vallonia pulchella, Miill. Fruticicola hispida, ZL.
rufescens, Penn. Dorcasia Berlandieriana, Mor.
griseola, Pfr.
Turricula terrestris, Chemn.
Aglaja fidelis, Gray.
Liguus fasciatus, Mil. Orthalicus undatus, Brug.
Carpenteri, Newc. Mormonum, Pfr. sequoicola, J. G. Coop. Diabloensis, J. G. Coop. Traski, Newc. Dupetithouarsi, Desh. ruficincta, Newc.
Gabbi, Newe. Glyptostoma Newberryanum, W. G. Euparypha Tryoni, Newe. [ Binn.
Tachea hortensis, Mill. Pomatia aspersa, Miill. * * * Cylindrella Poeyana, Pf. jejuna, Gid. Macroceramus Kieneri, Pf. Gossei, Pfr. Bulimulus serperastrus, Say. Floridanus, Pfr. multilineatus, Say. Dormani, W. G. B. Marielinus, P/r. patriarcha, W. G. B. alternatus, Say. Schiedeanus, P/r. dealbatus, Say.
GONIOGNATHA.
Punctum pygmeum, Dr.
ELASMOGNATHA.
Succinea Haydeni, W. G. B.
retusa, Lea. Sillimani, Bid.
ovalis, Gid., not Say.
Succinea Higginsi, Bld. Haleana, Lea. Mooresiana, Lea. Grosvenori, Lea.
80 TERRESTRIAL AIR-BREATHING MOLLUSKS.
Succinea Wilsoni, Lea. Succinea obliqua, Say. Concordialis, Gd. Totteniana, Lea. luteola, Gd. campestris, Say. lineata, W. G. Binn. Hawkinsi, bd. avara, Say. rusticana, (/d. Stretchiana, Bld. Nuttalliana, Lea. Verrilli, Bid. Oregonensis, Lea. aurea, Lea. effusa, Shuttl. Groenlandica, Beck. Salleana, P/r
VII. DESCRIPTIONS OF GENERA AND SPECIES.
Orver PULMONATA.
LINGUAL membrane varying from short and broad to long and narrow; teeth numerous, in numerous uniform transverse rows. Mouth usually with one or more horny jaws. Respiratory organ in the form of a closed chamber lined with pulmonic vessels on the back of the animal and covered by the shell when present ; edge of the mantle attached,—the entrance to the air-chamber being through an opening in the side, closed by a valve. Oper- culum almost universally absent. Animal hermaphrodite, with reciprocal impregnation, generally oviparous, terrestrial, fluviatile or marine, but respiring free air. Tentacles and eye-peduncles retractile or contractile.
Shell varied in form, sometimes rudimentary or wanting.
Eyes at the end of elongated peduncles, or on the head of the animal.
The Pulmonata are usually divided into three suborders, — Geophila, Limnophila, and Thalassophila, — names derived respectively from the comparatively terrestrial, fluviatile, and marine habits of the animals. These suborders are readily distinguished by the position of the eyes, either sessile or on peduncles, and the characters of the tentacles.
I have included in this volume only the species of the first suborder, though one species of the Limnophila, Carychium exiguum, is truly terrestrial. It will be understood also that I do not include any gill- bearing genus, however terrestrial may be its habits. Thus I omit many genera included in Vols. II. and IV. ;
GLANDINA, 81
Susorper GEOPHILA.
Eyes at the tips of elongated, cylindrical peduncles ; tentacles retrac- tile or contractile, cylindrical, shorter than, and placed under, the eye- peduncles, sometimes very small or wanting. Operculum never present in the adult. Animal usually terrestrial.
I do not propose any system of classification for the Pulmonata, but the genera found within our limits may be grouped by the character of their jaw and lingual dentition into
A. Agnatha. Jaw absent ; marginal teeth aculeate or quadrate.
B. Holognatha Vitrinea. Jaw in one piece ; marginal teeth aculeate.
C. Holognatha Helicea. Jaw in one piece; marginal teeth quadrate,
D. Goniognatha. Jaw in separate pieces, the upper median one usually trian- gular; marginal teeth quadrate.
E. Elasmognatha. Jaw with an accessory upper piece; marginal teeth quadrate.
This grouping, as is the case with any founded on one or two sepa- rate characters, uhites many genera otherwise widely separated, and as widely separates some quite as intimately connected by other, per- haps more important, characters. It seems to me, however, that these distinctions may be, in the present state of our knowledge, considered of family value, quite as well as those founded on the mantle, shell, or other character. The names Testacellide, Vitrinide, Helicide, Orthali- cide, Succinede, have also been used for the same divisions.
A. AGNATHA.
Jaw absent ; marginal teeth aculeate or quadrate.
Of this division or family we have within our limits only the genus Glan dina. Many other and varying genera, heliciform and limaciform, have been described from other fauna.
GLANDINA, Scuum.
Shdil oblong, fusiform, horn-colored ; whorls 6 — 8, the last attenuated at base. Aperture narrow, elliptically oblong; peristome simple; columella twisted for- ward at the base and truncated. Suture often crenulated or margined. Uni- form in color, or ornamented with longitudinal, usually brownish streaks.
Animal heliciform (see Vol. III. Pl. LIX.), elongated, narrowed anteriorly ; eye-peduncles long, having the eye-spots on the posterior face, behind the tips, which are deflected; tentacles half the length of the eye-peduncles, bulbous, and somewhat deflected at tip; on each side of the oral aperture is a retractile, palpiform appendage, attenuated at tip, and more or less recurved, nearly as long as the eye-peduncle, the bases separated by a fissure in front; buccal
VOL. IV. 6
82 TERRESTRIAL AIR-BREATHING MOLLUSKS.
pouch capable of a proboscidiform protrusion, the aperture furnished with three papille above and three on each side. Genital orifice at some distance behind the right eye-peduncle, Anal and respiratory orifices on the right of the mantle, under the peristome of the shell. Mantle thin, posterior, covered by a well-developed shell. No distinct locomotive disk. No caudal mucus pore.
The eggs are eight millimeters long, covered with a hard calcareous shell.
The subgenera Varicella and Oleacina, s. str., are not found within our limits, but only the
SusceNnus GLANDINA, s. str.
Shell ovate, or ovate-oblong, plicately striate, generally of a silken lustre, but never glittering, and usually decussated with delicate revolving lines ; suture crenulated ; aperture equalling about half the shell’s length, its peri- stome simple.
Jaw absent. Lingual membrane narrow, with chevron-shaped rows of uni- form, aculeate, separated teeth ; central tooth with a long, slender, straight base of attachment, with incurved sides, and with inferior lateral slightly expanded angles, and with the upper margin reflected and extended into a long, slender, acutely pointed cusp. There are no lateral teeth, the balance of the mem- brane being composed of marginal teeth of the pure aculeate form.
Each row of teeth on either side of the median line curves first backward, with the teeth rapidly increasing in size as they pass outwards, and then for- wards as the teeth gradually again become smaller; giving an irregularly crescentic shape to the half-row of teeth. This is shown particularly in Gl. Albersi and G. rosea, less so in Gl. truncata. The central tooth was overlooked by Wyman, Leidy, and other of the earlier investigators. It has since been detected in Gil. truncata,’ rosea, algira,’ Sowerbyana, plicatula, fusiformis,® Albersi’; in semitarum,® Phillipsi® of the subgenus Varicella; also solidula™” of subgenus Oleacina. This central tooth is rather difficult to study, being on a different plane from the other teeth, and apparently much less developed.
1 See L. & Fr.-W. Sh., I. Fig. 6. 2 Amer. Journ. Conch., V. 202, Fig. 1.
8 Fischer and Crosse, J. de C., XVI. 234, 1868 ; Moll. Mex. et Guat., Pl. IV. Fig. 10.
4 Same, Moll. Mex. et Guat. 73, Pl. IV. Figs. 6-9. § Thid., p. 73.
6 Ibid.
7 L. & Fr.-W. Sh., L Fig. 10, p. 19.
8 Proc. A, N. 8. Phil. 1874, 49.
9 Tbid.
10 Ann. Lyc. N. H. of N. Y., X. 347.
Ge @n i ee eee SS we
GLANDINA. 83
Its cusp is generally simple, long, and narrow; but in G. rosea it has a decided blunt cutting point, and in G. semitarum it has a long, slender cutting point ; for that of G. truncata, see below.
The side teeth are all of the purely aculeate type; the base of attachment is long, narrow, incurved at sides, gradually rounded above, expanded and bluntly truncated below, the general outline being somewhat like that of the sole of a shoe. From this base of attachment springs a large aculeate cutting point. These side teeth are like the marginals in Zonites, Limaz, etc. ; they may therefore be called marginal teeth, and the lateral teeth, usually present in the Vitrinea, may be said to be entirely wanting.
As stated above, the marginal teeth increase rapidly in size for a short dis- tance from the median line, and then gradually decrease in size, as they pass off laterally, the last tooth being still smaller than the first.
In illustrating the dentition of this genus, I refer to the figure on p. 297, Vol. Il., to show the general arrangement en chevron of the rows of teeth. Fig. A of my Plate I. is intended to show the shape of the individual teeth of G. truncata from the central to the extreme marginal.
I have not had an opportunity of examining the lingual membrane of G. bullata, Texasiana, decussata, or Vanuxemensis.
The restricted subgenus is confined almost exclusively to Mexico and Cen- tral America, but several species are found in our Southern Region, even as far north as South Carolina. There is also one Mediterranean species.
Glandina Vanuxemensis, LEA. Vol Tih. PE EAT Pig. 1.
Shell elongated, ovate-fusiform, thin and fragile, considerably transparent, pale fawn-color, in some specimens inclined to greenish, and generally flecked with distant, pale spots; the surface is, in a measure, coarsely granulated by the decussation of longitudinal and revolving lines, the latter of which are more distant from each other than the former, and become less and less dis- tinct towards the anterior portion of the whorl; whorls 7 or 8, the apical ones smooth and forming a mammillary tip; suture crenulated; aperture about one half the length of the shell, nearly three times as long as broad; columella strongly arched, and scarcely glazed by enamel. Length of axis, 68 mill.; breadth, 25 mill.
Glandina Vanuxemensis, LEA, Trans. Am. Philos. Soc., V. 84, Pl. XIX. Fig. 78, Obs. I. 196 (1837). — PFEIFFER, Symbole, III. 91. — Binney, Terr. Moll., II. 299, Pl. LXII. Fig. 1. — W. G. Binney, T. M., IV. 141; L. & Fr.-W. Sh., I. 15. — FiscHer and Crossk, Moll. Mex., 100 (1870).
Glandina Vanuxemii, Tryon, Am. Journ. Conch., II. 226 (1866).
Achatina Vanuxemensis, REEVE, Conch. Icon., Pl. XIII. Fig. 48. — PFEIFFER, Monog. Helic. Viv., II. 294.
Oleacina Vanuxemensis, PFEIFFER, Brit. Mus. Cat., 36; Mon. Hel., LV. 643.
84 TERRESTRIAL AIR-BREATHING MOLLUSKS.
A species of the Mexican fauna, but actually found also in the Texas Region. I have not seen any other specimen than the one figured in Vol. IIL. Animal and dentition unknown.
Glandina truncata, GMELIN. Vol. III. Pls. LIX., LX., LXI., Fig. 2; LXIL, Fig. 2.
Shell strong, ovate-fusiform or ellipsoidal, obtuse at tip, of a pale ashy fawn- color, or rather alternately striped with ash-color and fawn-color, and more or less tinted rose-color, the surface shining and delicately fluted with longitudi- nal, raised, and rounded striz; whorls 6 or 7, moderately convex, the last constituting three fourths the length of the shell, ‘somewhat compressed at the middle, so as to become in a measure cylindrical, narrowing forward and rounded at base; suture strongly marked, delicately crenulate ; aperture about one half the length of the shell, often more, and twice as long as broad, narrow, ovate-lunate, acute posteriorly, obtusely rounded anteriorly ; peristome nearly rectilinear at its middle portion, and springing somewhat forwards; columella arched at its lower portion, and decidedly truncate at base; throat salmon- colored; edge of peristome pale. Average length, 37 mill., often very much longer, even 100 mill. ; breadth somewhat more than one third the length.
Bulla truncata, GMELIN, p. 3434.
Buccinum striatum, CHEMNITZ, IX. 36, Tab. CXX. Fig. 1028, 29?
Bulimus striatus, BruauiEre, Encycl. Meéth., I. 366.
Cochlicopa rosea, FErussac, Prodrome, 356 ; Hist. des Moll., Pl. CXXXYV. Fig. 3, Pl. CXXXVI. Figs. 6-10.
Achatina rosea, DESHAYES, Encycl. Méth., II. 10 (1830); ed. Lamarck, VIII. 313.
Achatina striata, DESHAYES in Lam., ed. 3, III. 381. — CHEMNITZ, ed. 2, Tab. III. Figs. 3, 4.
Achatina truncata, D’OrBIGNY, Moll. Cub., I. 163, Pl. X. Fig. 13. — REEVE, Conch. Icon., Pl. XIII. Fig. 47. — Cuemnirz, 1. c. (Bul.), Tab. XXXVIII. Figs. 21, 22 (Achatina), No. 78. — Preirrer (nec Glandina), Mon., III. 512.
Polyphemus glans, Montrort, Conch., II. 415, Fig. civ. (1810).—Say, Journ. Acad, Nat. Sci., I. 282 (1818); Nich. Ene., ed. 3 (1819) ; ed. Binney, 13, 7. — Férussac, Tabl. Syst., 11. ;
Glandina truncata, Say, Amer. Conch., II. Pl. XX. (1831); ed. Binney, p. 34, Pl. XX. ; ed. CHENv (Bib. Conch.), III. 28, Pl. VII. Figs. 2, 2 a. — PFEIFFER, Mon. Helic. Viv., II. 286. —DrKay, N. Y. Moll., 56 (1843). — Mrs. Gray, Fig. Moll. An., Pl. CCCI. Fig. 5 (ex Bost. Journ.).— Binney, T. M., II. 301, Pls. LIX., LX., LXI. Fig. 2; LXII. Fig. 2.—W. G. Binney, T. M., IV. 141, Pl. LXXX. Fig. 9; L. & Fr.-W. Sh., I. 15, Fig. 5 (1869). — LErpy, T. M. U.S., I. 258, 259, Pls. XIV., XVI. (1851), anat. — Wyman, B. J. N. H., IV. 416, Pl. XXIII. (1844), anat. — Tryon, Am. Journ. Conch., II. 225 (1866). — Hoae, Tr. Roy. Microsc. Soc. n. s., XVI. Pl. XIII. Fig. 84 (dentition).
Oleacina truncata, PFEIFFER, Mon. Hel. Viv., IV. 638. —Ib., Brit. Mus. Pulmonata, p. 23. |
GLANDINA, 85
Planorbis glans, DEKAY, 1. c. 56.
Glandina parallela, W. G. BINNEY, Phila. Proc. 1857, 189; T. M., 1V. 140; L. & Fr.-W. Sh., I. 17. — Tryon, Am. Journ. Conch., Il. 226 (1866).
Oleacina parallela, P¥¥IFFER, Malak, Blatt. 1859, 51.
Glandina Texasiana, part, W. G. Binney, T. Moll., 1V. Pl. LXXVII. Fig. 21, not of PFEIFFER.
Atlantic and Gulf States from South Carolina to Texas, thus inhabiting all the Southern Region. Very common on the islands and keys along the coast.
Animal: see above, p. 81, Vol. III. Pl. LIX.
The habits of this animal are somewhat aquatic. It is found on the sea- islands of Georgia, and around the keys and everglades of Florida; and in these situations the shell often attains the length of four inches, — when found on the oyster hummocks and less humid localities, it seldom exceeds one inch in length. Mr. Say found it in the marshes immediately behind the sand-hills of the coast. It is most readily found in the centre of the clumps of coarse grass on these marshes. In young individuals the spire forms but a small proportion of the shell, but in the old it often forms one third of the length.
The animal is in part, if not altogether, carnivorous; and its powerful lingual membrane, armed with long, sharp-pointed teeth, is well adapted to its food. By its action the soft parts of its prey are rapidly rasped away, or are forced in large morsels down the cesophagus. The animal has been seen to swallow entire the half-putrid remains of a Helix, and to attack Limaces confined in the same box with it, rasping off large portions of the integument, and in some instances destroying them. In one instance an individual attacked and de- voured one of its own species, thrusting its long neck into the interior of the shell, and removing all the viscera. I found many specimens of Polygyra volvoxis in the stomach of individuals collected by me at St. Augustine, Fla.
The testicle is an oval mass, separated from the liver as in the Limaces. The epididymis appears from a hilum in the side of the testacle; at first but slightly tortuous, it becomes convoluted just before ending. Its accessory gland is large. The penis sac is long, large, and clavate, very gradually en- larging from the base to the summit. The vas deferens, which joins the latter point, is long, moderately tortuous, and wide. The retractor muscle is inserted into it near its termination in the penis sac. The bladder is oval, constricted ; its duct is as long as the oviduct. The vagina is moderately broad. The cloaca is short. The exterior generative orifice is on the right side of the head, considerably posterior to the tentacles. (See Vol. I. Pls. XIV., XVI.)
Jaw absent. Lingual dentition as described above. There are about 34— 1—34 teeth in each row. I have shown in Pl, I. Fig. A, the central and various marginals from the first to the last tooth. The figures show the teeth as seen from below, thus giving a perfect view of the bases of attachment. The eighth tooth seems to be the largest, in another the sixth. The central tooth I find great difficulty in studying. It appears to have a long, slender
86 TERRESTRIAL AIR-BREATHING MOLLUSKS.
base of attachment, truncated and emarginate above and below, with slightly expanded lateral angles. ‘The sides are somewhat incurved, giving the tooth the appearance of a simple modification of the base of attachment of the mar- ginals. There is a single median cusp with obsolete side cusps, and a long pointed median cutting point. (See the enlarged figure.) There are no lat- eral teeth. ‘The marginal teeth are all of purely aculeate type.
The shell is a very variable one, as shown by the figures in Vols. IIL and IV. The form from Key West, figured in Pl. LXI. Fig. 2, is a well-marked variety, but surely is not a variety of G. Texasiana, as I formerly supposed it might be. After further opportunities of judging by the study of more numer- ous specimens, I am led to change my opinion as to the specific distinction of the form I formerly called G. parallela. (See outline figure of Pl. L-XII.)
The rose-color of the living shell soon fades.
Glandina decussata, DESHAYES. Vol. III. Pl. LXI. Fig. 1.
Shell oblong-conic, thin, shining, horn-color; whorls 7 to 8, longitudinally striate, and covered with numerous minute revolving lines; suture slightly crenulated; aperture oblong, half as long as the shell; columella curved, trun- cated, covered with light callus. Length, 50 mill.; diameter, 18 mill.
Achatina decussata, DeESHAYES in FR. Hist. 182, Pl. CXXIII. Fig. 34; PL CXXIYV. Figs. 33-35 (1850). (Vide Preirrer, Mon., IV. 644).
Glandina truncata, var., BINNEY, T. M., IJ. 302, Pl. LXI. Fig. 1.
Glandina corneola, W. G. BINNEY, Proc. Phila. Acad. 1857, 189 ; T. M., IV. 139.
Glandina decussata, TrYON, Am. Journ. Conch., II. 227 (1866). — W. G. BINNEY, L. & Fr.-W. Sh., I. 18 (1869). — Fiscner and Crossk, Moll. Mex., 112 (1870).
Oleacina corneola, PFEIFFER, Mal. Blatt. 1859, 51.
A Mexican and Guatemalan species, also found in the Texas Region at Devil’s River and on the banks of the Nueces River. It is very rare in collec- tions.
Animal, dentition, and genitalia unknown.
Glandina bullata, GouLp. Vol. III. Pl. L-XII. a.
Shell elongate ovate, ventricose, widest a little behind the middle, very light and thin, and so translucent as to show the whole of the pillar by transmitted light, very pale horn-color, tinged with rusty brown towards the aperture, shin- ing, and marked longitudinally with fine rounded strie; whorls 5, tumid, the last composing about seven eighths of the shell; suture delicate, not
strongly impressed ; aperture two thirds the length of the shell, narrow-lunate, _
somewhat dilated by the moderate arching of the pillar margin, the lower third of which takes the direction of the axis; pillar margin covered by a delicate lamina of white callus. Length of axis, 37 mill.; breadth, 20 mill.
: |
GLANDINA. 87
Glandina bullata, Gou.n, Pr. Bost. S. N. H., ILI. 64 (1848); T. M., II. 298, Pl. LXII. a. —W. G. Brnney, T. M., IV. 189. — Tryon, Am. Journ. Conch., II. 226 (1866). — W. G. Binney. L. & Fr.-W. Sh., 1. 19 (1869).
Achatina bullata, Prrirrer, Mon. Hel., II. 512.
Oleacina bullata, PFrirrERr, Brit. Mus. Cat., 24,
Near New Orleans, and in St. Laundry Parish, Louisiana; a species of the Southern Region,
Animal unknown.
Probably a variety of G. truncata.
Glandina Texasiana, PFrrirrer.
Shell oblong, rather solid, with crowded longitudinal striw, shining pellucid, flesh-colored ; spire convex-conic, obtuse; suture pale, minutely denticulated ; whorls rather convex, the last rather longer than the spire, some- what attenuated at the base; columella quite arched, forming at its base a white, twisted, abruptly truncated lamina; aperture scarcely oblique, acutely oval; peristome simple, obtuse. Length 29, diameter 103 mill.; length of aperture 16, breadth 5} mill.
Fig. 9.
Achatina Texasiana, P¥rrEIFFER, Novit. Conch., VIII. p. 82, Pl. XXII. Figs. 11, 12 (1857) ; Proc. Zool. Soc. 1856.
Glandina Texasiana, W. G. BiInnEy, T. M., IV. 140. —