FIFELDBOORK of Yilinois Land Snails FRANK COLLINS BAKER ILLINOTEIS NATURAL HISTORY SURVEY MANUAL & History Survey Library Natural UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIG NAT, HIST, SURV. Digitized by the Internet Archive ~~ in 2010 with funding from University of Illinois Uroana-Champaign http://www. archive.org/details/fieldbookofillin00bak | Fieldbook of Illinois Land Snails ra) re 7 5 °°) Pe Loe. haere Oh TLL YN OTS Henry Horner, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Joun J. Hatuinan, Director Fieldbook of Illinois Land Snails By FRANK CoLLins BAKER Printed by Authority of the State of Illinots NATURAL HISTORY SURVEY DIVISION TuHeopore H. Frison, Chief MANUAL 2 Urbana August 1939 STATE OF ILLINOIS Henry Horner, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Joun J. Hacuinan, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Joun J. Hainan, Chairman WILLIAM TRELEASE, D.Sc., LL.D., Biology Henry C. Cow.es, Ph.D., D.Sc., Forestry L. R. Howson, B.S.C.E., C.E., En- gineering WituiaM A. Noyes, Ph.D., LL.D., Chem. D., D.Sc., Chemistry Epson S. BasTIN, Ph.D., Geology ARTHUR CuTTS WILLARD, D.Eng., LL.D., President of the University of Illinois NATURAL HISTORY SURVEY DIVISION Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF TuHeEopore H. Frison, Ph.D., Chief SECTION OF ECONOMIC ENTO- MOLOGY W. P. Fuint, B.S., Chief Entomologist C. C. Compton, M.S., Associate Ento- mologist M. D. Farrar, Ph.D., Research Ento- mologist J. H. Biccrer, B.S., Associate Ento- mologist S. C. CHANDLER, B.S., Southern Field Entomologist L. H. SHROPSHIRE, M.S., Northern Field Entomologist W. E. McCautey, M.S., Assistant Entomologist C. J. Wernman, M.A., Assistant En- tomologist C. W. Kearns, Ph.D., Research Fellow in Entomology ARTHUR E. RITCHER, B.A., Research Fellow in Entomology R. C. ReEenptorFF, M.S., Research Fellow in Entomology K. L. Knicut, M.S., Research Fellow in Entomology SECTION OF INSECT SURVEY H. H. Ross, Ph.D., Systematic En- tomologist Cart O. Monr, Ph.D., Associate En- tomologist, Artist B. D. Burks, Ph.D., Assistant En- tomologist G. T. Riecet, B.S., Assistant Ento- mologist SECTION OF FORESTRY JAMES E. Davis, M.F., Extension For- ester LEE E. YEAGER, Ph.D., Forester SECTION OF AQUATIC BIOLOGY Davip H. THompson, Ph.D., Zoolo- gist GEORGE W. BENNETT, Ph.D., Limnoi- ogist DOoNALD F. HANSEN, Ph.D., Assistant Zoologist C. L. SCHLOEMER, Ph.D., Assistant Aquatic Biologist SECTION OF GAME RESEARCH AND MANAGEMENT Ratpo E. YEATTER, Ph.D., Game Specialist C. S. SPOONER, JR., M.S., Junior Bi- ologist SECTION OF WILDLIFE EXPERIMENTAL AREAS Artuur S. Hawkins, M.S., Game Technician F. C. BELLROSE, JR., B.S., Assistant Game Technician COOPERATIVE WILDLIFE RES- TORATION PROGRAM (State Department of Conservation and U.S. Biological Survey) H. G. ANDERSON, M.S., Juntor Bi- ologist Louis G. Brown, B.S., Junior Biol- ogist R. E. HESSELSCHWERDT, B.A. Junior Biologist SECTION OF APPLIED BOTANY AND PLANT PATHOLOGY L. R. TEHON, Ph.D., Botanist J.C. Carter, Ph.D., Assistant Bota- nist G. H. Boewe, M.S., Field Botanist SECTION OF PUBLICATIONS James S. Ayars, B.S., Editor (70738—2 M—1-39) ass 2 TATE OF ILLINOIS Hexay Horner, Governor +. dabeadal MENT OF REGISTRA Pies EDUCA usin ge Hacuman, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Jorn J. HaLiran, Chairman WiILLiAmM TRELEASE, D.Sc., LL.D., Biology atioro Henny ©. Cow es, Ph.D., D.Sc., Forestry LR. Howson, B.S.C.E., C.E., En- ARTH gineering olosntitileat otveaclod President ie the Universit op A. Noves, Ph.D., LL.D., Chem. D., Chemisiry Epson S. Bastrx, Ph.D., Geology Dairies cana y of Illinois UR CuTTs WILLARD NATURAL HISTORY SURVBY DIVISION mei Illinois SCIENTIETC ENTIEG ARP TECH SECTION OF ECONOMIC ENTO- ND TECHNICAL STAFF Frison, Ph.D., Chief SECTION OF AQUA tosnpitipan apedeloS Davin H. Taompson, ais YA yal p 7k W.Y. Pos’, B.S, Chief Entomologist Ai , Cotorst axes S., Associate Ento- —- W. BENNETT, Ph.D., Limnol= LMG f P My. Pare ar, Ph.O., Research Ento- Bay Poo A Hansen, Ph.D., Assistant ee oe ©. L. Scu-oemer, Ph.D., Assistant Eg TS 4 SIO EERO Aquatic Biologist Ht COLxtsi ee fe ee = SECT, OF GAME RESEARCH MOS, B.S., Southern Fishes ANAGEMENT Sesceserze. MS. Northern RaLtpu BE. Yeatrer, Ph.D., Game gs. ® REMRIIENS Specialist Re Mifsene< MS. Ascietee S. Spooner, jJr., MS., Junior Bi- Esiomologisi ologtst Wine as, M.A tony Ep. SECTION OF WILDLIFE fomolog: x! EXPERIMENTAL AREAS i + A VIOe aR O P hs. Research Artaur S. HawRtawtoyy areaiglod . Felisy t2 Sovomologs Technician Artsur © Rs rcHER, B.A., Research F. C. Bervrose, Jr., B.S., Assistant S¢llow ix Extomology daca Technician R. C. Renprorrr, M.S., Research at WILDLIFE RES- Psiiow in Eniomology aaledorvt zaddan TION PROGRAM K. L. Knrout, M.S., Research Fellow in F niomology SECTION OF INSECT SURVEY H. H. Rass, PS.D., Systematic En- fowrtologisi Cart O. Mour, Ph.D., Associate En- tomologisi, Artist B. D. Burks, Ph.D., Assistant En- ORGS. mologist SECTION OF FORESTRY James §&. Davis, M.P., Extension Soar- ester Lee E. Yeacer, Ph.D., F vesier (State Department of Conservation and U.S. Biological Survey) H. G. ANpbErRSoN, M.S., Junior Bi- ologist Louis G. Brown, B.S., Juntor Bicl- ogtst R. E. HessE_scHWERDT, B.A. Junior Biologist SECTION OF APPLIED BOTANY AND PLANT PATH G@D@deete owarlot issisiant E-RQyod oxedpingee hy con, -Ph.D., Botamést d. = > vaca Ph.D., Assistant Bota- G. ‘a Boewe, M.S., Field Botanist SECTION OF PUBLICATIONS James S. Ayars, B.S., Editor (707 38—2 M—1-39) 7 Se > a. th Pree mB OO RD HIS fieldbook is intended primarily for the use of ama- teur students of nature who wish to learn the names and something of the habits of the snails found in Illinois. Its size and organization are such that it may conveniently be carried into the field by high school and college classes and other nature study groups. Information contained in this fieldbook is based on a col- lection of more than 20,000 specimens of Illinois Mollusca, obtained principally by a detailed survey of the state. The financing of this survey was made possible by a small special appropriation to the Illinois Natural History Survey, available the biennium beginning July 1, 1931. The Natural History Survey was fortunate to obtain the services of Mr. Frank Collins Baker, Curator of the Museum of Natural History of the University of Illinois and an author- ity on the classification of these invertebrates, to prepare the text and to direct the field collections necessary for a thorough distribution record of our native species within the state. Mr. Baker spent part of the summers of 1931 and 1932 in the field directing the collection of specimens and, since then, has spent much time in the identification of material and the preparation of the manuscript for this manual. Dr. Thural Dale Foster, now deceased, at that time a graduate student in the Department of Zoology of the Univer- sity of Illinois, was employed by the Survey as assistant to Mr. Baker on this project for three months in the summer of 1931 and two months in the summer of 1932 to collect land Mollusca in all parts of the state. The collections resulting from this special work are now deposited on loan with the Mollusca material belonging to the Natural History Museum of the Jniversity of Illinois. Other collections deposited in the University’s Natural History Museum, notably those of Ferriss, Nason and Hinkley, as well as many records published by other students of Illinois vii fauna, have been drawn upon whenever necessary. This fieid- book, therefore, embodies all the present state of knowledge concerning the number of I]linois species of land snails and their distribution throughout the state. The introductory chapter of this fieldbook contains inter- esting and useful information on the general characteristics of Illinois land snails—where they live, how they grow and how they may best be collected and studied. In the descriptive section of the book, an attempt has been made to present a simple account of each species of land snail found within the state. Each species is illustrated by a figure or figures accurately drawn to show its characteristics. Keys to families and genera have been included to aid in the identification of species. Students unfamiliar with keys should consult the paragraphs on their use in the introductory chapter. The description of each species of snail has been made brief, and only the important features that distinguish one species from another have been mentioned. The habitat preferences of the species as they occur in I]linois are noted. The drawings for the illustrations are the work of Dr. Carl O. Mohr, Associate Entomologist and artist with the Natural History Survey. It is felt that the inclusion of mostly new and original drawings, instead of copies of time-worn illustrations made many years ago, will be welcomed by all students of the Mollusca. Of the shell or animal figures, all but those at the top of pages 88 and 120 and on page 143 were drawn from specimens. Adapting the manuscript to the same general format as the Illinois Natural History Survey Manual 1, Fieldbook of Illinois Wild Flowers, as well as its general styling and indexing, has been the work of Mr. James S. Ayars, editor for the Survey. It is the hope of those engaged in the preparation of this fieldbook that its publication may stimulate the study of an interesting subject not only among young people in schools and colleges of the state but also among individuals of all ages who find pleasure in exploring the mysteries of the out of doors. THEODORE H. FRrison Chief Urbana January 16, 1939 Pee N OW LEDGMENT § CKNOWLEDGMENT is made to Dr. Henry A. Pilsbry, Curator of the Department of Mollusca of the Academy of Natural Sciences of Philadelphia, for determination of and information concerning several species of the Pupillidae and other small snails. A student of Dr. Pilsbry in 1889, the author of this fieldbook has been inspired by this dean of American conchologists during a half century of scientific endeavor. It is fitting that appreciation of this guidance be made here. Thanks are due to Dr. Harley J. Van Cleave, Professor ot Zoology, University of Illinois, for advice and criticism during the preparation of this volume; and to Dr. Allen F. Archer, Museum of Zoology, University of Michigan, for information concerning the status of certain species of Polygyra. The author is indebted to Dr. Van Cleave and to his son, Philip, for several collections made in the vicinity of Urbana and in other parts of Illinois; and to Dr. Alvin R. Cahn, formerly Assistant Professor of Zoology, University of Illinois, for ma- terial from a number of places in the state. Grateful acknowledgment is made to the memory of Dr. Thural Dale Foster, companion and friend during the survey of the state which preceded preparation of this volume, for not a little of its value is due to his painstaking search for rare or new Illinois records. The author acknowledges his indebtedness to the following colleagues: Dr. Carl O. Mohr, Associate Entomologist of the Illinois Natural History Survey, for his painstaking work on the excellent figures which illustrate this manual; Dr. B. D. Burks, Assistant Entomologist of the Survey, for assistance in preparing and checking keys; Mr. James S. Ayars, Survey Editor, for the careful revision of the manuscript and for many suggestions which have made the work of greater value. The author wishes to express his deep appreciation to Dr. T. H. Frison, Chief of the Illinois Natural History Survey, through whose interest the molluscan survey of 1931-32 and the preparation of this fieldbook were made possible. FrANK CoLiuIns BAKER Cons £N TS Lanp Snaits: WHat THEY ARE AND WHERE They Live...... 3 Heed and Feeding Habits of Snails................. 5 SS NSS ote | (i a a an a 9 UIE RB AES PEVE =o. o's vivid ot oe wp fa wee tele e's « wna de 9 PU ICCe) SS0OIIS ek nod ke hae s betes wx eee if Summmenirrer the COUCCEOF. ... 2. eo ek cee kw aee 13 ERMINE CVEIECIOGENS 0070S c-c ee ce e v ee eee eee 15 MEMERETIEM URINEES oo yes chev So's ew iwed bbe aw ee cy we due 16 mrarwecation of Land Snails. ..... 0... 52.052. 0. 2a eee ewe 17 Smee edentity band Shells::.......222.....) 00.02.0005 20 Pronouie siapertance of Land Snails........)............ 23 Mectersertimois Land Snails............... 622.0005. pA memeaey OF Llinoise. 2... Pe 26 Reiners a Geolosical History........5.........2234.2565 30 Beene nal Pauna of Wlinois:.....-..:....2..2..0-.. 33 Ie Sates IGATIVE FO LLLINGIS..... 5. i.e ee. oe oe we tee ee | DURES OPTE Ee Be GS ho ae de = 34 as ee Oe 37 Sindee € Posouranchiata. .... <2 c5..00 . ak aoe woe ew een ee 39 Rami beiteitidae cis cP. oo .o amas ee 39 Nomiemrmimonatae. oo 2.8. er ood. okies oe oes 40 sunotder otylommatophota....... . > 20% eee * - "oh t= Land Snails What they are and where they live mee ye SN AT Tes What they are and where they live Among the beautiful pictures That hang on Memory’s wall, Is one of a dim old forest That seemeth best of all. —Auice Cary, Pictures of Memory HO does not enjoy a ramble through a. deep old forest, with its majestic monarchs of the woodland, its climbing vines, trumpet creeper and wild grape, and its carpet of colorful flowers and soft mosses? Birds flit about in the sunlit glades, squirrels perch on the lower branches of trees, eying the intruder with apparent curiosity or fear. Butterflies float lazily through the air, and bees dart from flower to flower. A fat old woodchuck waddles peacefully along until he observes the intruder, when he makes a dash for his hole in the side of a hill. On the forest floor are ‘many old logs, branches of trees and the litter and debris characteristic of an ancient woodland. Here lies hidden a wealth of animal life that escapes the attention of the casual observer. Hunting for snails——Let us turn over one of the old logs, not too large or heavy, and see what is concealed beneath. What a scampering at once takes place! Beetles, spiders, bugs, several salamanders, a few centipedes, all make a bee line for a place in which to hide. But there are a few animals beneath the log that do not run away. Among these are white or yellow larvae of certain beetles, as well as slugs and various land snails with spiral shells. Snails with shells.—Let us look carefully at this land svaz/, fig. 1, now just emerging from its she// and beginning to crawl slowly over the upturned surface of the log. Its yellowish shell is about an inch in diameter—large for that of an Illinois land snail. This is placed on what may be called the dack of the animal and is tilted somewhat to the left side. At the head end of the animal are two pairs of feelers: a pair of short tentacles and, above them, a pair of long eye pe- duncles. At the tip of each of the latter is an eye. The feelers are constantly moving about, touching every obstacle in the path _ [3] 5: ILLINOIS NATURAL HISTORY SURVEY MANUAL of the snail. If a long eye peduncle 1s touched, the snail immedi- ately withdraws it outside in, in such manner as one sometimes removes the finger of a glove. The visible part of the snail’s ody, which ends in a slender, tapering fai/, is long and narrow. Irregular granulations that cover the body give it a rough appearance. The underside of the body, known as the foot, 1s flat, and when the snail lifts its head from the log wavelike pulsations along this foot may be seen. Locomotion of the snail is accomplished not by a picking Eve Peouncce too Fic. 1—Animal of land snail, Polygyra albolabris (Say). Parts of the body are indicated. up and setting down of the foot but by a sliding movement produced by a wave of muscular contractions along the foot. The soft part of the anima! containing most of the vital organs remains within the shell. It is covered by a tough skin called the mantle. The thickened portion of the mantle which borders the aperture or opening of the shell, and which is known as the mantle collar, secretes the material which adds new shell around the aperture, for only by the addition of new shell ma- terial around the edge of this opening does the snail shell in- crease in size. Noticeable is the mucus which is exuded from a gland near the mouth. The mucus assists the snail in crawling by smoothing or lubricating the path over which it passes. On the right side of the body, just under the edge of the shell, may be seen the breathing orifice or lung opening through which the snail takes in air, for it is a lung breather just as we are. All of the Illinois land snails are lung breathers, and all species but one belong to the Pulmonata, an order which takes its name from a Latin word meaning lung. Let us search the log still farther. We tear off a piece of the bark which is loose or started. On the inner side of this bark we BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS =) find snail shells of several different sizes. Some are globular like weed seed; others are elongated like the seed of grass. Some are brown or blackish; others, horn-colored or yellowish. Some are opaque; others, almost transparent, like paraffin. One has stripes; another, spots. Slugs.—Not all snaillike animals have shells into which they can retire. Under our log we find one apparently without a shell. This is known as a s/ug, page 129. It is black in color, about an inch in length, and it has a peculiar shieldlike pro- jection near the head. Under its shield we find a small, flat shell which acts as a protection to the breathing organ. Another slug, a different kind, is about 3 inches in length, of a whitish color covered with black spots, and has no shieldlike projection near the head. This slug is always covered with mucus and when handled exudes great quantities of this matter. Only five species of slugs are common in Illinois. Food and Feeding Habits of Snails If we place one of our Illinois woodland snails in a glass jar and permit it to crawl up the side, we may observe that it has on the under surface of the head a mouth, which repeatedly opens and closes. When we look closely we see a rough, tonguelike object which is pushed out of the mouth and pulled in somewhat like a cat’s tongue in lapping milk from a saucer. This is the radula or tooth-bearer with which the snail obtains its food. When the snail is crawling up the side of a glass jar, we may observe this tongue licking up the particles of vegetable matter on the glass, or if we place a piece of lettuce in the jar we may see the animal biting off with its horny jaw small pieces of the lettuce which it then scrapes into smaller pieces with the radula. The mouth parts.—If we cut a longitudinal section from the head of a dead, preserved snail, we may see the relationship of the radula to the other parts of the head and mouth. Such a section is shown in fig. 2. The ribbonlike radula of our woodland snail is drawn over a part of the mouth called the cartilage. Different muscles move the cartilage and the radula backward and forward, allowing the snail to rasp off particles of food brought down between the lips. The radula wears out at the anterior or front end, which is used more than any other part. To repair this wear, the whole radula grows forward from the core, much as our finger nails grow from their bases. 6 ILLINOIS NATURAL HISTORY SURVEY MANUAL Made of a material called chitin, the radula is yellowish and transparent. In the mouth of the animal, it is partly coiled and saddle-shaped. If we remove the radula from a preserved snail, spread it on a glass slide and examine it with a microscope of rather high power, we see that its upper side is covered with many rows of little projections called teeth. Each row of teeth running crosswise of the radula has a central tooth which is symmetrical. On either side to right and left of this central tooth are many other teeth, which are not nearly so symmetrical. Two com- { £0 5 fn) . ecres, gbee ») $6 ot = H E iti ang “ig. eit aie 9 Fic. 2.—Cross section of head of a land snail: 1, mouth; 2, radula; 3, cartilage bearing jaw; 4, jaw; 5, upper lip; 6, esophagus; 7, core of radula; 8, new teeth forming; 9, mucus glands; 10, orifice of mucus glands; 11, posterior cartilage muscles; 12, cartilage; 13, lower lip; 14, anterior cartilage muscles. = =a og J lst plete half rows of the teeth on the radula of a snail are shown in fig. 3. These are, of course, greatly magnified. Some of the teeth, still more highly magnified, are shown in fig. 4. The manner in which the teeth lie upon the radula, with a portion bent over or reflexed, is shown in fig. 5. The number of teeth on a radula is astonishingly large. Thus, the radula of Po/ygyra albolabris, the woodland snail we are studying, has 91 teeth in a single row and, as there are 120 rows, the total number of teeth is 10,920. Carnivorous snails do not have so many teeth, and these are differently shaped, being sharp and daggerlike, as those of the land snail Hap/otrema BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS i; concavum, shown 1n fig. 6. This snail has but 51 teeth in a row and only 32 rows, 1,632 teeth in all. Though the teeth of snails furnish evidence on which species may be separated, our purpose in this fieldbook is not Rae 0 g% = yr x s = bs R = sq i. Ww Pat SN MINS SS aannn 1S — me a9 16 ie Fic. 3.—Two rows of teeth from the left side of a radula membrane of Polygyra tridentata (Say). BASE OF ATTACHMENT TO RADULA REFLECTED PORTION Sipe Cuses CuTTING POINT MiDOLE CuSsP CUTTING POINT CUTTING ee. BASE OF ATTACHMENT LATERAL BOOTH | 'O: RADULA ate TOOTH MARGINAL TOOTH Fic. 4.—The three kinds of teeth, lateral, median and marginal, on the radula or lingual ribbon of a land snail, greatly magnified. SVEN OAS FY a TE OS UA Re EE RE FADE CE ST S POSSE LOE, cra FET Fic. 5.—Longitudinal section of the radula of a land snail. The teeth lie on the radula membrane much as shingles lie on a roof. MAA 7 4 Fic. 6.—Teeth from the radula or lingual ribbon of the carnivorous snail Haplotrema concavum (Say). to discuss the subject of finer anatomy. Instead, our object is to point out the readily observable means of recognizing the shells of Illinois land snails. Food of snails.—The great majority of snails feed upon vegetable matter. Thistles, nettles, fungi, succulent leaves and ‘Juepunqe ov sveaddcjod pur s lodnd *sploj1uoz 919YM SHO] Bury304 Yam » , , . . . > , , . +S . F / Soop IVIIGVY PUL[POOM sloUT][]] UAIYINOS JIsis9}DvAvYS vB SI sBurpying oy) puryog yUNOY UOlUL) ‘sseg OI;Y JO YIION BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 9 the fruit of the horsetail are often part of their diet. They will not eat pungent plants of any kind. Not all snails eat vegetable matter. A few are carnivorous and feed upon earthworms, leeches or other snails. Because the body of the land snail is peculiarly shaped to fit into the coiled shell, the digestive, circulatory, locomotor, nervous and reproductive organs are not so easily recognized and studied as those of many other animals. But all of these sys- tems are found in the land snail, and in the various species they often show individual patterns which add evidence to the differences based on form and size of shell. How Snails Reproduce In a small cavity in our old log, we note a mass of jellylike globules, eggs which have been laid by the white-lipped wood- land snail, Polygyra albolabris. All Illinois land snails lay eggs, which vary in number from a few to 40 or more, in moist locali- ties where they are protected from the sun’s rays. The eggs may be found hidden under old logs, especially those on which the bark is loose, under chips, leaves, pieces of peeled-off bark and all sorts of debris. May and June are the usual periods during which land snails lay their eggs. Twenty or 30 days later, the young snails hatch and start on their life journey, reaching full maturity in about two years. Some land snails do not lay eggs but give birth to fully formed young. However, no species with this birth habit are found in Illinois. Lung-breathing land snails, the only kind considered in this fieldbook, are hermaphroditic; that is, both sexes are in the same animal, the sexual organs being closely associated in the body, and the external openings of both sexes being merged in one opening. Study of the variation of the organs in the different species aids greatly in the classification of the land snails. Where Land Snails Live Land snails may be found almost everywhere, even in places where the dry nature of the habitat would seem to exclude life of any kind. Forested river valleys are perhaps the most favorable habitats for snails, especially those valleys having outcrops of limestone rock. The largest, most highly colored shells of the various species of land snails are found where lime is ‘sjivus JoyIO pur pUubasjojdY FY ‘x1ydmosafyy AO} Sv ]JOM se ‘padSAJO 2VJUap AOJ YVJIQVYy poos VY ‘Ayunoy adog ‘epuoosjosyy svou JIAILY O1LYGD 94) HD AYOY BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 1] available in quantities; areas where granitic or volcanic rock abounds are usually poor places for snails. Often, isolated wood- lands in the midst of cultivated areas afford favorable snail habitats. Snails abound on some of the highest Illinois hills and in some of the deepest valleys; in comparatively dry places and in swamps and marshes. Curiously enough, the rights of way of railroads, especially embankments, afford good collecting lo- calities, and a distinct fauna, evidently driven from the prairies by the advance of civilization, has taken refuge in this environ- ment. Most snails are associated with distinctive kinds of en- vironment. Some are restricted to the heavy, virgin forests; others are limited to the more open woodlands which have been cut over. Many species are found in regions forested with oak, maple, willow and other deciduous trees; only a few are asso- ciated with coniferous trees. Some are found in abundance on and near limestone cliffs, whereas others are more or less re- stricted to the vicinity of bodies of water, or the bottom lands or floodplains of rivers and streams. Some, as the amber snails of the genus Succinea, live among cattails bordering ponds and streams and may = found even in the water; these snails are in a measure amphibious. A few snails are found on prairies in the grass, but the fauna of such places is not large. No pulmonate mollusk will live where sand, lime or ashes in a pure state are found. A few typical habitats are shown in the illus- trations contained in this volume. Collecting Land Snails Perhaps the best place to find snails, especially the small species, is under loose or started bark of fallen tree trunks that have been lying on the forest floor so long that the wood has become somewhat rotten. Here both individuals and species of land snails are usually abundant. As many as 15 different kinds of snails have been found in one such favorable location. In the shelter of rocks or boulders may often be found a number of the smaller snails called pupoids. Under leaves, in old brush piles, under old boards near sawmills, and under and in the general debris of the forest floor these animals may usually be found. Sometimes the larger species may be seen either crawling upon or clinging to tree trunks, and many times in wet weather snails 12 ILLINOIS NATURAL HISTORY SURVEY MANUAL may be found on the leaves of forest shrubs and other plants. In fact, almost any place may harbor one or more land snails. The admonition to be given the beginning conchologist is to look everywhere; he may be rewarded by finding species hitherto unknown in his vicimity. The spring and summer months when moisture is abundant are best suited for the activity of snails. The most favorable time for collecting them is after a rainy period in summer. In late fall, and also in very dry periods, snails bury themselves in the ground or under debris of some sort and close the shell aperture with a secretion which forms a leathery flap called an epiphragm. They may thus be found in any of the winter months by a little patient digging about stumps, or under matted leaves and started bark. Making the collection.—In collecting land snails, the con- chologist should not confine his activities to living specimens. Even the empty, so-called ““dead” shells should be picked up if they are not badly broken or bleached. Among these may be representatives of some species the living specimens of which are not easily found. The empty shells are just as useful for establishing a record of the presence of a particular species or variety as are the shells containing animals. When well cleaned, they make good cabinet specimens. Often, close examination of the ground will reveal shells of many of the small species, the interesting pupoid snails. Washings from cliffs and debris along the shores of streams— known as stream drift—may contain shells of many species not commonly found alive. Keeping records.—It is of great importance for the student to keep a record of his field observations in a book or on sheets of paper, which may be called freld data blanks. This record should give the exact location of the place where each specimen is found, the nature of the habitat, the kinds of trees and other vegetation in the immediate vicinity, the condition of the ground where the collection is made, the nature of the weather at the time and the temperature of the air. It may be possible for the amateur collector to supply very valuable information to science by keeping exact records of his collecting localities. A different number should be given to each collecting location even 1f two or more locations are in the same general region. For example, in one general region there may be an isolated woodland, a river valley and a railroad em- BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 13 bankment, all visited. Each should be given a number. Ac- curate records kept faithfully will reward the conchologist with a full account of his season’s work. Apparatus for the Collector Apparatus for collecting land snails is very simple. A number of wide-mouthed bottles, two or three ounces in capacity, several homeopathic vials and a tin box that fits the pocket are all the containers necessary. One or two small vials should be partly filled with alcohol for those specimens that are desired only for the shells. Alcohol will kill the snails and keep them from adhering to the side of the vial. It will also preserve the animals and prevent the ill- smelling odors that arise from decaying matter. A pair of small forceps or tweezers is indispensable for picking up small specimens like the pupoids and also for sorting the collection at home. The points of the tweezers should meet exactly, and the spring should not be too rigid, or, in closing the points, the collector may apply too much pressure, breaking delicate shells like those of the zonitoids. It is a good plan to tie a string to the tweezers to prevent loss when they are laid aside in the collecting of larger snails. The string may be tied around the wrist or attached through a buttonhole to the jacket or shirt of the collector. The large snails may be placed in the tin box or wide- mouthed bottles and killed after the collecting trip is over. A stout knife is necessary for the purpose of tearing off small pieces of bark, turning over debris and digging snails out of their burrows in the ground. A trowel is often helpful for digging up the earth in favorable habitats. A very convenient implement for the collector is the Ferriss hoe, made by filing an ordinary hoe blade into heart-shaped form. This may be used for protection against venomous snakes—rattlers, moccasins and copperheads—common_ in some parts of southern Illinois, and also for pulling over rock piles and digging up forest debris. To collectors who may be affected by poison ivy, this implement will be found of great value for pulling aside the vines when they cover the ground or old stumps and logs. The snail collector should be careful to avoid ruthless destruction of the habitats where he is studying. He will notice “d19Y Ud. 9q (eu S[9Qe] pure S[EIA [[? Ys ssvla 1OMVAIP ou L “STOUTTT] jo AJISIOATUL) “A1OISIF] [PANIEN JO WINASN TA] 944 ul SJIUIQBO [[?ys ay 1B JOUINe euL BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS ‘MS that very few animals of any sort are beneath recently fallen trees. Years are required for the ground underneath a fallen log to become fully suited as a dwelling place for snails, sala- manders, spiders and the host of other animals which live be- tween logs and the soil. When a decaying log is rolled from its established location, the conditions favorable for sheltering these animals are completely destroyed. For this reason, the snail collector who moves a log should, in the spirit of conserva- tion, carefully roll it back into its place, securing as nearly as possible a perfect fit to the old spot where it lay. Preserving Specimens Preservation of the specimens gathered from a collecting trip is of the first importance. At the time the live specimens are collected, they may be covered with dirt and slime. These substances must be washed off in clear water. The “‘dead”’ shells may be washed clear of dirt in running water, the inside of each shell cleaned out at the aperture with wire or tweezers. They may then be dried by being laid on blotting paper or newspaper. The living specimens may be dropped into boiling water, which will kill the animals and render easy the removal of 2 soft parts from the shells. For this latter purpose a bent wire sharpened at one end, or a fishhook fastened in a wooden handle, makes a good implement. If a wire or fishhook is inserted in the dead snail and the shell turned, the animal may be easily removed. The shell should be washed clean of mucus and then allowed to dry naturally. No artificial heat should be applied, as this will crack the shell. The animal that is to be preserved by the collector may be killed by drowning. A small bottle should be filled to the very top with cold water from which dissolved air has been removed by boiling. The snail should then be dropped into the water and a small piece of glass placed over the mouth of the bottle. This will exclude all air. In about 12 hours the snail will have died with its body, tentacles and eye peduncles extended. It may be preserved in a 4 per cent solution of formalin; or it may be placed in a 50 per cent solution of alcohol for a few days and then transferred to a 75 per cent solution of alcohol. Small specimens which have been collected in the home- opathic vials partly filled with alcohol may be taken out and dried on blotting paper. 16 ILLINOIS NATURAL HISTORY SURVEY MANUAL Slugs may be drowned by the method described for land snails and may then be preserved in alcohol or formalin. Labels and Cabinets The labeling and preserving of a collection are of the first importance. The small, cleaned and dried shells may be kept in homeopathic vials, and the large specimens in cardboard trays or boxes. Each label should be prepared with great care, as upon accurate records depends much of the value of the collection. MoLLuScAN SURVEY OF ILLINOIS PUPAIDES.... MARGINATUS........(SayJ Illinois:..Macon..Co,..2..mi..$..0f Decatur, Wabash... RR....richt...of ways. Deposited by Illinoi$ Natural History Survey No. ZF 372/ Det. byBaker Date, Summer, 1926 MuseuM oF NaTuRAL History, UNIVERSITY OF ILLINOIS . Fic. 7—Sample label for trays of shell cabinet. Information on each label should include the scientific name of the specimen, the exact locality from which it came, the date of collecting and any note concerning the habitat that may be of interest and value. A sample label is shown in fig. 7. The trays in which the collection is kept may be of several sizes but, for convenience in handling, a certain degree of uni- formity should be maintained. If a size of 2 inches by 1 inch is decided upon for the smallest tray or basic unit, dimensions of the larger trays should be multiples of these measurements: 2 by 2, 2 by 4 or 4 by 4 inches. In the Museum of Natural History of the University of Illinois, the basic unit is 3 inches by 1 inch. Other trays are 3 by 114, 3 by 2, 3 by 3 and 3 by 4 inches. Extra large size trays are 3 by 6 and 6 by 6 inches, but these are too large for most land snails. All the Museum trays are half an inch in depth. If the collector cannot afford to have trays made at a box factory, he may use spool boxes or other small cardboard containers. Glass receptacles called shell vials are sold by laboratory supply houses and, as these have no flange at the mouth, they are more desirable for small specimens than are the homeo- pathic vials. The shell vials may be of a size just enough shorter BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 17 than the width of the tray to permit a short cork to be placed in the mouth. For a 2- by 1-inch tray, a bottle 134 inches in length is desirable. The larger shell specimens may lie loose in the tray. It is well to index the collection either in a book or upon library catalog cards. Much of the valuable information previous- ly recorded on the field data blanks may be entered under the name of each specimen. Cabinets are necessary, but they need not be expensive. If available, a spool cabinet is very good. One of the best cabi- nets for keeping a collection of land snails in good order is a legal blank case, which is about 14 inches high, 10 inches wide and 15 inches deep. It has 10 drawers, each drawer slightly less than an inch deep and capable of holding several trays such as have been described. These drawers are admirable for the land snails found in Illinois. The case may be purchased from office supply companies for about $6. With the case, the trays and the vials, the collector has most of the equipment for beginning a valuable and interesting collection of land snails. Classification of Land Snails In the study of land snails, a system of naming is used by which they may be known to people interested in them. The shell itself has certain features which are given names. By a description of the form and position of these named parts of the shell almost anyone may know or identify a snail. In fig. 8, a shell of Polygyra tridentata frisoni is pictured with the parts indicated. The shell in nature is covered with a horny envelope called the periostracum or epidermis, which protects the limy part of the shell substance from destruction by the carbonic acid in the air or water. When the snail perishes and its shell dries, this epidermis usually peels off, exhibiting the chalky nature of the shell substance. Form of shells.—The shells of Illinois land snails vary greatly in form. They are rounded, elongated, flattened and disc- like, or turreted. They range in size from that of one of the little pupoids, less than one-sixteenth inch in length, to that of the white-lipped snail, more than an inch in diameter. The aperture in different species varies in form and may be modified by the presence of large or small projections known as 18 ILLINOIS NATURAL HISTORY SURVEY MANUAL denticles, folds or lamellae, sometimes improperly called feeth. The surface of the shell exhibits a feature called scu/pture, represented by growth lines. These are made as the animal adds to the size of its shell by depositing a limy substance at the edge of the aperture-from the little cells bordering its soft parts. The sculpture may be very fine, like thread wound tightly on a LABIAL DENTICLE PERISTOME PERISTOMAL DENTICLE UMBILICUS PARIETAL DENTICLE PaRIETAL WALL LABIAL DENTICLE APERTURE Fic. 8—Named parts of shell of the snail Polygyra tridentata frisoni F. C. Baker. _spool, or it may be so coarse that it forms elevations called ribs. Sometimes well-defined spiral marks or lines are added, forming in many cases a latticed pattern. Color of shells.—Varying widely in color and pattern, the shells of the land snails of Illinois occur in many different shades of yellow, brown and gray. Some are of uniform color; others are marked by one or more spiral bands or a number of zig- zag spots and cloudings of darker color. Shells of many of the forms, for instance some of the pupoids, are translucent and like paraffin in appearance; other shells are opaque and of a dark brown or nearly black color. Certain species have a glassy or shiny shell of a brownish color. All of the variations in size, form and color of shell enter into the naming of snails. Naming snails.—Snails are known by their scientific names, which are always of Latin form and are often of Greek or Latin BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS hey origin. The white-lipped snail mentioned previously is known as Polygyra albolabris (Say). The first name, Polygyra, which happens to be of Greek origin, indicates the genus to which the snail belongs; the second, a/bolaéris, which is of Latin origin, denotes the species. The word in parentheses is the last name of the man, Thomas Say, who first described this species. His name is in parentheses because this snail is no longer in the genus in which he placed it. Originally, Say gave this snail the name a/bolabris and placed it in the genus He/ix. It was then known as Helix albolabris Say. Later, when other scientists decided that the species a/bolabris should be removed from the genus Helix and placed in the genus Po/ygyra, the name of the original describer was included in parentheses, and the snail then became known as it is today: Polygyra albolabris (Say). Not all species of snails have names of Greek or Latin origin. Vertigo morsei Sterki was named for Edward S. Morse; Polygyra fosteri F. C. Baker, for Thural Dale Foster; Gastrocopta holzingeri (Sterki), for John M. Holzinger. It is not uncommon for conchologists wishing to honor fellow scientists or friends to give a Latinized form of their names to new species of snails. Our system of classification is known as the binomial or two-name system and was first used definitely by the great Swedish naturalist Linné, or Linnaeus, in the year 1758. The system has been formally adopted, and no names published previous to this date are now used by students of the natural sciences. Most present day workers in the Mollusca have extended the binomial system to include recognizable differences occurring within species. Subforms are designated by a third or variety name. The species Po/ygyra albolabris is divided into a number of forms or varieties. The typical form is known as Polygyra albolabris albolabris. Other Illinois forms of this species given distinguishing variety names are known as Polygyra albolabris dentata and Polygyra albolabris allent. Reasons for scientific names.—Many people ask why we do not use common English names for snails as we do for birds and mammals. We may answer that there are so many different species of snails which resemble each other closely that 1t would not be practical to give each a common name. Many scientific names are not more difficult to pronounce or understand than are some of the names in common use which have been taken from the Latin and Greek languages. For example, we speak 20 ILLINOIS NATURAL HISTORY SURVEY MANUAL of a stadium, a rostrum, an auditorium. Scientific names be- come simple when we understand and use them frequently. Another reason for using Latin and Greek for scientific names 1s that these languages are more nearly universal than any others. Use of them allows the form of the name to remain un changed. The name Polygyra albolabris is clearly understood by conchologists of almost any nationality, while the name many- whorled, white-lipped snail might mean nothing to anyone except American or English students. Pronunciation of scientific names.—Although scientific names are of Greek or Latin derivation or form, they are pro- nounced in the United States as if they were of English origin. Students who have learned the Latin pronunciation common today in public schools of the United States sometimes experi- ence more difficulty in sounding scientific names than do those who have studied only English. Just as in English, the letter g is pronounced sometimes as in green and sometimes as in gentle; c sometimes as in cat and sometimes as in ce//; »v like the English v rather than the English w. Guides to pronunciation may be found in the introductory section of Webster’s New International Dictionary under “‘Rules for the English Pronunciation of Latin.” Divisions of snails.—Snails, like all other groups of animal life, are separated into divisions according to different char- acteristics that several may have in common. These divisions are class, order, family, genus and species. Thus our white- lipped snail, the species Polygyra albolabris (Say), belongs to the class Gastropoda, or snails; the order Pulmonata, or snails that breathe air by means of a lung and that have certain charac- teristics of the internal organs in common; the family Poly- gyridae, or group containing all of the snails that have teeth, internal organs and shell more or less like our white-lipped snail; and the genus Po/ygyra, to which belong the snails more intimately related to our snail. The whole system of nomencla- ture is simple, and the amateur conchologist need have no fear concerning his ability to comprehend it. How to Identify Land Shells The young collector of Illinois land snails will naturally ask, ‘““How am I going to find out what species I have collected? Must I run through the entire book to see if my specimen matches a certain description or figure?’ Such a question is Railroad habitat near Mayview, Champaign County. The railroad embankment is a good habitat for some small snails which live in very dry places. Ze ILLINOIS NATURAL HISTORY SURVEY MANUAL pertinent, and we have provided devices known as keys, from which a species may be identified by certain characteristics or combinations of characteristics that are peculiar to it. Key to the families.—Suppose you have found a large snail with brown color bands encircling its coarsely ribbed, dome- shaped shell. You first consult the key to families on page 38. Under 1 you find, “Animal having a well-developed spiral shell into which it can withdraw,” and “Animal having only a rudi-) mentary shell, or shell wanting entirely.” The shell is spiral and well-developed; so you consult both parts of couplet 2, as the key directs. If the shell has plaits or denticles extending far back into the whorl, the key identifies it as belonging to the family Strobilopsidae. But as this shell has no plaits, you next consult couplet 3. Because the shell is dome shaped, you move. to couplet 4, and because it has a lip with a sharp edge you con- sult couplet 7. The coarse ribs of the shell identify the snail) as belonging to the family Endodontidae. Keys to the genera.—Turning to page 83, you find a key to the genera of the family Endodontidae. In the first couplet, you read: “Shell 34 to 1 inch in diameter and marked by brown spiral bands or scattered blotches of brown color,” and “Shell “4 inch or less in diameter and without contrasting markings; even brown or horn in color.” As your shell is nearly an inch in) diameter, you know it belongs in the genus Anguispira. Turn- ing to the key for this genus, page 84, you find: ““Whorls with irregular vertical dashes and spots,” and “Body whorl with two horizontal stripes.’”’ As your shell has a body whorl with two horizontal stripes, you decide that its name must be d4nguispira kocht. Using the keys.—The keys contained in this fieldbook are based on the most obvious characteristics of the shells of adult specimens found in Illinois. They will not aid in the identifica tion of young or immature snails. For instance, shells of the immature specimens of Po/ygyra have a thin lip with sharp edge, whereas shells of the adult snails of this genus are characterized by a reflected or turned-over lip. Young polygyras are likely to be confused with adult specimens belonging to the family Endodontidae or even with those of the large Zonitidae. Poly- gyra shells differ from those of the Endodontidae in usually being yellowish in color and from those of the Zonitidae in having a surface which is never smooth or polished. Young snails are usually found with adult specimens, and the general BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 23 similarity between young and old helps to place the young with the adults of their species. : Careful attention to these keys should enable a student to identify adult specimens of any of the species of land snails found in Illinois. The keys are intended for aid in the identifi- cation of the snails of Illinois only and could not be used very ‘successfully for land snails in general or for the land snails of any other one state. Although in adjoining states and in similar situations some of the same genera and species occur as in Ili ‘nois, the presence of other genera and species not found in this ‘state would tend to make the keys inaccurate. Economic Importance of Land Snails Land snails are of varying importance economically. None of the Illinois land snails is so large as the European edible snail, Helix pomatia, and none is eaten now, although some species at one time furnished food for the American Indian. As food for other animals, the Illinois land snails are of some value. Many birds are known to eat such small snails as the pupoids and zonitoids. Salamanders and newts eat the small slugs of the forest. Mice, moles, shrews and some squirrels eat the larger snails, and the broken shells are frequently found near a burrow or at the base of a tree where some animal has had a snail feast. As garden pests, several species of snails and slugs are worthy of note. The little glassy zonitoid known as Zonitoides arboreus often occurs in such abundance in the garden patch as to do considerable damage. Slugs also live in the garden and eat the succulent vegetables which are grown for the table. These animals are nocturnal in habit and are seldom noticed. In the daytime they may often be found beneath boards in or near the garden. At least two species of large slugs, Limax maximus and Limax flavus, have been introduced into this country from Europe and are found more or less abundantly in some greenhouses, where they may seriously damage growing plants. In some cities the large Limax maximus ‘has escaped from the green- houses and has been found in yards and nearby fields. The best precaution against a visitation of these slugs is a quantity of fine ashes scattered over the soil. In an effort to become free from the 1 irritating ashes, the slugs will soon exhaust themselves by secreting an abundance of mucus. ‘Id uerysezed aya jo yard ose yorum “sq[ty eseya ul punoy oq Avur s[ivus jo satoads Auvyj ‘Ajunos uous) ‘vuuy jo samy inos sattul UaAaS UOTB—aL IH * PR, : Wee = Ny BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS Pde) One relationship between snails and other animals 1s com- monly overlooked. In the bodies of many kinds of snails para- sitic worms undergo a necessary part of their development. Fortunately, none of the Illinois land snails is known to harbor parasitic worms directly of importance to man. There are, however, many species of land snails whose bodies shelter parasites belonging to the flatworm group known as the flukes or Trematoda. These worms, growing inside the bodies of land snails, never reach maturity in the snails, which are called in- termediate hosts. For full development the trematode must enter the body of some mammal, bird, amphibian or reptile. Relatively little is known of the life-history details of these parasitic worms carried by land snails in Illinois, though the larvae have been frequently observed. Collectors of Illinois Land Snails Many eminent students of science have contributed to our knowledge of the nature and extent of the land snail fauna of Illinois. Chief among these is Thomas Say, father of American conchology, who lived for a time at New Harmony, Indiana, and who studied and gave names to many species common in our state. Amos Binney and his son, William G. Binney, were the first to place the fauna on a seatine bash of classification, and not a few of our species have the names of these famous conchologists as their describers. The name of Thomas Bland, an intimate associate of William G. Binney, is indelibly connected with the study of land snails of Illinois and other parts of North America. Augustus A. Gould of Boston, Isaac Lea of Philadelphia and Bryant Walker of Detroit have contributed largely to the subject. Among living students of this branch of science who have studied the Illinois fauna is Henry A. Pilsbry of Philadel- phia, who has placed the subject on a sound basis of classification and whose treatment has been followed in this fieldbook. H. B. Baker of Philadelphia and George H. Clapp of Pittsburgh, dis- tinguished students of the land snails, have added much to our knowledge of some of the species of land snails that live in IIli- nois. Many citizens of Illinois have studied and collected the land mollusks of the state and have left a large and interesting bibliography. Most of these are now dead, and few others have become interested enough to take their places. 26 ILLINOIS NATURAL HISTORY SURVEY MANUAL Among the early Illinois naturalists who made extensive collections and added greatly to our knowledge of the Mollusca of this state may be mentioned Robert Kennicott, who was Director of the Chicago Academy of Sciences and who studied the zoology of Illinois (1845-1885)*, W. W. Calkins of Chicago (1870-1885), John Wolf of Canton (1865-1870) and H. A. Ulffers of southern Illinois (1850-55). Later, another group of men took up the study and greatly advanced our knowledge: W. A. Nason of Algonquin (1865-1910), J. H. Ferriss of Joliet (1890-1925), A. A. Hinkley of Rockford and Dubois (1895- 1920), W. A. Marsh of Aledo (1880-1900) and W. S. Strode of Bernadotte (1890-1910). Two men who wrote little but who made good collections of Illinois snails for others to study should also be mentioned: George T. Marston of Green Bay, Wisconsin, and C. S. Hodgson of Albion, Illinois. The collections of some of these students have been de- posited in the Natural History Museum of the University of Illinois, along with the loan collection from the Natural History Survey, and the material is available for scientific study. Among the collections are those of Nason, Ferriss, Strode, Hodgson and the author. Physiography of Illinois The state of Illinois is well situated for the study of geograph- ic distribution. It covers 54 degrees of latitude, lying between parallels 37 and 42%. A marked difference in climate exists between the widely separated northern and southern boundaries. In the southern tip near Cairo the weather is so warm that cotton flourishes, and the climate is of a very temperate nature even in the winter months; whereas in the northern part near the Wis- consin border tamaracks grow, and the ground is frozen for a large part of the winter. The difference in climate is reflected in the fauna. Illinois is partly surrounded by water bodies. The great Mississippi stretches along the entire western side of the state, the almost equally large Ohio borders the southern, and the Wabash flows along a portion of the eastern border. On the *The dates indicate period of greatest activity. The author of this fieldbook, who should also be mentioned among eminent conchologists of the state, began his study of the land snails of Illinois in 1895.—Editor. se 2 gs: Q /ROOVOIS x STEPHENSON ati fOWARDS Sa WOOLPH N & 5 Map of Illinois showing counties and principal river valleys ‘s[ivus jo soiods Auvul Joy syejIqey psoye sute;dpooy Popoom pue soutavs ‘sy[UM Ad][VA 9YT *AJUNOD UOTTWIIA SOT]IAURG] JO ISAM IAL l UOI[IUII9 A Big ay} jo Ad|[eA BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 29 northeast, Lake Michigan washes the shores for many miles. Within the state’area are several large river valleys. The Illi- nois, which is the largest river in the United States lying wholly within the borders of a single state, the Rock, Kaskaskia, Big Muddy, Little Wabash, Embarrass, Kankakee, Fox and Sanga- mon rivers afford many attractive valleys, usually well wooded and providing favorable habitats for snails. Tributaries of these streams form a great network of waterways throughout the length and breadth of the state. Scarcely another state of the Union has so many stream valleys, which means that Illinois presents unusually good hunting grounds for the conchologist. Plain and valleys.—Much of Illinois is an undulating plain which in a few places has been rather deeply dissected by streams and rivers. In the central and southern parts of the state some of the river banks are towering cliffs which with their castellated crests form picturesque features of the landscape. The bluffs of the Mississippi attain a height 360 feet above the level of the river. The banks of the Ohio rise in places as much as 100 or 200 feet above the water. In the lower Illinois valley, in Calhoun and Jersey counties, some of the cliffs reach an elevation of approximately 300 feet above the river. The banks of the Rock River, especially those near Oregon, are famed locally for their height. Terrain of this rugged type, although not representa- tive of Illinois as a whole, furnishes favorable habitats for cer- tain species of snails. Hill regions.—South of Harrisburg and Carbondale is an eastward extension of the mountains of Missouri, known as the Ozarkian Uplift. This area, which in places attains an elevation of 1,100 or more feet above sea level, harbors a greater variety of land Mollusca than any other section of Illinois. The dis- ection of this uplift by erosion has produced many hills, some of them precipitous, which rise 350 to 650 feet above adjacent valleys. In Jo Daviess County is another hill region which extends into Wisconsin and is sometimes called locally “the little Switzer- land of America.” Although this region lies at approximately the same distance above sea level as the Ozarkian Uplift, its hills are less precipitous and do not rise to such heights above adjacent valleys. Neither the Jo Daviess County nor the southern Illinois hill regions felt the influence of the great glaciers which in other places planed the hills and filled the valleys with debris. ) 30 ILLINOIS NATURAL HISTORY SURVEY MANUAL Prairie and lake areas.—Outside of the hill regions and the river valleys, Illinois is relatively flat and contains large areas of cultivated land, once prairie, unfavorable to molluscan life. Although Illinois is primarily a prairie state, a large part of the original prairie areas has been so altered by cultivation as to destroy conditions under which snails grow abundantly. Prairie conditions, however, are still found in many localities, some of them isolated. In the northeastern area bordering Lake Michigan rise some high moraines, where mollusks may be found. In Lake and some of the adjoining counties may be seen a few bodies of water, but aside from this district there is no area in the state compar- able to Wisconsin and Michigan with respect to multitude of lakes, large and small. The dune-bordered shores of Lake Mich- igan afford but poor habitats for land mollusks. Mollusks in Geological History Mollusks occur in the oldest stratified rocks, the Cambrian, laid down over 600 million years ago. However, these are all marine animals, snails and clams, a few of which are known from the rocks of Illinois. The first known land snails are from the Carboniferous rocks of the Coal Period, about 300 million years ago. Most of these have been found in fossil tree stumps in Nova Scotia. Several Jand snails are known from the coal fields of Pennsylvania. In the great Chalk Period, the Cre- taceous, land snails became common, and in the period known as the Tertiary, about 60 million years ago, they became abun- dant. Their number has increased to the present time. No ancient land snails are at present known from Illinois, but it is very likely that such animals lived here, as in Nova Scotia and Pennsylvania, among the luxuriant vegetation of the Coal Period. Glacial periods.—Very late in geological time a glacial or ice period developed which sent great ice fields into Illinois and other parts of the United States. With the exception of a small area in the northwestern part, mostly in Jo Daviess County, and a larger area in the extreme southern part of the state, IIli- nois was completely covered with an ice sheet. The ice came into and retreated from Illinois at least three times, the first invasion, the Kansan, as well as the second, the Illinoian, reaching nearly to the southern boundary of the state, stopping BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 31 on the north side of the hills of the Ozarkian Uplift. The third invasion reached only the eastern and northeastern parts of the state as far south as Shelbyville in Shelby County. Limestone bluff in Giant City State Park, Jackson County. Snails are found in the woods above the bluff and in the rock crevices. These huge ice fields brought down great quantities of clay and rock, which were deposited at the edge of the ice to form moraines, the ridges which are now a marked feature of the landscape in various parts of the state, as near Champaign, Shelbyville, Bloomington, Paxton, Pontiac, Aurora, Algonquin and Summit. Interglacial intervals.—The geological time of the huge ice fields, known as the Pleistocene or Glacial Period, lasted about one million years, divided among the several ice invasions. The periods between these invasions, called interglacial inter- vals, were probably of long duration, chavivands of years, and the climate at its most genial time is believed to have been warmer ‘svrAdAjod aFivy yi JO satdads [essAos YIIM JOYIIF “O} Sjivus [jets Auvut punoy oq Av uOIsoaI sIyy uy ‘AJUNOD UOL[IUOA “MOWOF] JO JsvoYy INOS “1O}UIM UT SPOO A tee BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 33 than that of today, since both the pawpaw and the osage orange are found in geological deposits far to the north of their present habitats. Each period was probably subjected to a warm, a cold temperate and a boreal condition as the ice advanced and the climate became arctic. The reverse condition prevailed when the ice retreated and the climate became warmer. Effect of glacial periods.—The effect of this great field of ice moving over the state was to kill all life that could not re- treat in front of it. Such sedentary animals as snails could not get away and must have been killed when the ice filled the valleys and buried the life under the debris brought down. It has been ascertained from a study of the snails in these deposits that the ancient land snail fauna of the state was not exactly like that living today. Members of some species, which differed in a small way from their relatives now living, are known today as races of these species. A few species became wholly extinct. Others no longer live in Illinois but are now found far to the west or north of the boundaries of this state. A few species once common over the state are now found in northern Wisconsin and Minnesota and in southern Canada. A deposit called loess, formed centuries ago probably by the wind blowing fine dust from the river bottoms, usually contains land snail fauna quite unlike that of today. When the ice began to melt and retreat, and the climate grew warm enough for plant life to become established again, the land snail fauna once more took possession of the state. There was migration from Indiana on the east, Missouri on the west and Kentucky on the south. Since the retreat of the ice, some species of land snails more or less foreign to these areas have come into Illinois, along with the species which normally live in this region, and are now widely distributed over the state. The foreign species are found mostly in the river valleys border- ing the southern and western parts of the state. Some of this migration may have been geologically very recent. The Land Snail Fauna of Illinois All snails described in this fieldbook—in fact, all snails— are included in the class Gastropoda. The following pages describe 122 species and races of land snails found in Illinois. Of these, all species but one belong to the order Pulmonata. Six of the species described have been accidentally introduced at ILLINOIS NATURAL HISTORY SURVEY MANUAL from foreign countries into: greenhouses and other places in cities. The native fauna, therefore, comprises 116 species and races. These are divided among 14 families and 28 genera. se : : . : It is of interest to compare this fauna with that of other — states. The modern classification and nomenclature of the land Mollusca represent such changes from those in use a few years ago that only five catalogs are at present available for direct comparisons. These relate to the fauna of Michigan (Winslow, 1936), Ohio (Sterki, 1907), Pennslyvania (Brooks, 1931), Indiana (Daniels, 1904, 1915) and Alabama (Walker, 1928). It is probable that additional species of Mollusca will be found in Indiana, bringing the number of species and races of that state to approximately the total of those in Illinois. Comparisons of two genera, Polygyra and Gastrocopta, show the large Illinoian fauna of these important groups. Table 1 compares graphically the total land snail fauna, the polygyras and the gastrocoptas of the six states in which the Mollusca have been most carefully studied. Alabama alone exceeds Illinois in the number of species represented. 2 Table 1.—Total number of species, subspecies, races and vari- eties of Mollusca and of two important genera reported from six states. Total : State Nance Polygyra Gastrocopta Authority Date Illinois 122 34 13 Baker 1939 Michigan 103 23 8 Winslow 1926 Indiana 100 28 5 Daniels 1915 Ohio 105 22 8 Sterki 1907 Pennsylvania 102 22 5 Brooks 1931 Alabama 185 58 14 Walker 1928 It is possible that a few additional species may be found to inhabit Illinois, especially the northern portion bordering Wis- consin and the eastern adjoining Indiana. Land Snails Native to Illinois —— ) . a a. GaN 6S a 1S Native to Illinois Class GASTROPODA The class Gastropoda includes all snails, those which live in the ocean, in lakes, rivers and pools, as well as those which live on land. Order PROSOBRANCHIATA In the order Prosobranchiata are the snails which breathe by means of plumelike gills. The great majority of the species of this order live in the ocean, but many live in fresh water, and not a few live on land far removed from water. Only one species, however, is known from Illinois. Order PULMONATA The order Pulmonata includes all but one of the species of land snails which live in Illinois. The animal breathes by means of a lung, as is explained in the introductory chapter of this fieldbook. Suborder STYLOMMATOPHORA Most families, genera and species of snails living in Illinois are included in the suborder Stylommatophora of the order Pulmonata. This suborder embraces most of the land snails of the world. Animals of this suborder have four tentacles, arranged as pairs. The superior, or longer, tentacles with the snail’s eyes at the tips are retractile. The inferior tentacles are very short. Suborder BASOMMATOPHORA Animals of this suborder of Pulmonata have tentacles that are more or less flattened and triangular or subcylindrical. The tentacles are contractile but not invertible as in the true land snails, the sub- order Stylommatophora. The eyes are placed at the inner base of the tentacles and not at the end, as are those of the true land snails. Most species of this group live in or near fresh water, though they breathe by a lung, much as do the Stylommatophora. In the following pages, the actual width or length of the specimen is represented by a line near the figure. [37] 38 14. ILLINOIS NATURAL HISTORY SURVEY MANUAL KEY TO FAMILIES Animal having a well-developed spiral shell into which it can withdraw, p: 40.(Swail) 2. 2. ».2-.25 ae ee ee 2 Animal having only a rudimentary shell, or shell wanting entifely, pp. 129, 131)(Slag)...4426 Se ee 14 Parietal wall of shell with plaits extending far back into whorl and with one or two plaits emerging from aperture eM a ce he STROBILOPSIDAE, p. 110 Parietal wall of shell not with plaits extending far back into whorl and emerging from aperture, pp. 39, 44............ 3 Shell broader than high, spire flat or dome shaped, pp. 49, 92. .4 Shell higher than broad, spire pointed or elongate, pp. 96, 122.9 Shell with lip reflected or turned back, edge thickened, p. 40. .5 Shell with lip not reflected or turned back, edge sharp, p. 83..7 Shell 14% inch or less in diameter... VALLONIIDAE, p. 116 Shell at least 144 inch in diameter, usually from % to 1 inch in diameter... fo. ooo. Oe eee 6 Whorls of spire not separated by: a suture. see i eee eee ret So - HELICINIDAE, p. 39 Whorls of spire separated by a distinct suture............ et teky dvs ae ae POLYGYRIDAE, p. 40 Surface of shell dull, coarsely ribbed. ENDODONTIDAE, p. 83 Surface of ‘shell polished, smooth, p.. /02-. .. 3... eee 8 Spire more or less rounded, p. 66; vitreous, with umbilicus Relatively stall... cs. 0.00. nee ZONITIDAE, p. 64 Spire flattened, p. 92; not vitreous, with umbilicus very Wien ay Lew ons cae iret ass Ga HAPLOTREMATIDAE, p. 91 Aperture occupying one-half or more length of shell, p. 122. . 10 Aperture occupying not more than one-third length of shell, pO. 2. 2... SR hs ee Os 11 Shell with brown markings on surface. . BULIMULIDAE, p. 63 Shell with surface yellowish, unmarked. SUCCINEIDAE, p. 121 Aperture without plications or denticulations of any kind, De 120. conc os ge dese dale vg cl das ee oe 12 Aperture with 1 or more plications or denticulations, p. 136. .13 Shell yellowish, polished......... COCHLICOPIDAE, p. 120 Shell Wrowns. dulloS.\.4.. sexa eek PUPILLIDAE (part), p. 93 Aperture round; provided with denticulations........... FLAT ER OO Le eg hy Nene PUPILLIDAE (part), p. 93 Aperture long and narrow, p. 136; provided with a single plat On Parietal wall... eee ELLOBIIDAE, p. 135 Mantle covering only anterior portion of body............ er: 3 Steals ae WIPER oes dente ee OL gee Rae LIMACIDAE, p. 128 Mantle almost or entirely covering body................ SESE Taher vcs lon ain ts Ol PHILOMYCIDAE, p. 131 HELICINIDAE 39 Family HELICINIDAE The family Helicinidae is abundantly represented in tropical countries, Mexico, Central America and the islands of the West Indies. Though belonging to the Prosobranchiata, an order of sea and freshwater snails, members of the Helicinidae are truly terrestrial or land animals. Unlike the animals of Pulmonata, the order of land snails common in Illinois, those of the Helicinidae possess a horny operculum or lid with which they may tightly close the shell against all intruders. Animals of the Helicinidae have a rather long snout, truncated at the end, and long, slender tentacles; each eye is on a little swelling at the outer base of a tentacle. Genus HENDERSONIA A. J. Wagner The only genus of the family Helicinidae found in Illinois, Hendersonia is known in the United States, China and Japan. All of the shells are similar to that of Hendersonia occulta. HENDERSONIA OCCULTA (Say) The reddish or yellowish shell of Hendersonia occulta is very thick, and its surface is marked by fine, curved ribs. It measures about one-fourth inch (5-7 mm.) in diameter. The spire, which is dome shaped, has 642 whorls. The periphery of the body whorl is made angulate by the presence of a relatively sharp carina which borders the sutures on the spire whorls. The base of the shell is rounded and is without an umbilical opening. The aperture is lunate in shape, and the outer lip is greatly thickened, forming a heavy projecting ridge. Only the adult shell has this ridge. This snail, formerly named Helicina occulta, is now very rare in Illinois, and is at present known only from near Athens, Menard County. It may be found in dry well-wooded places under and about forest debris. Though rare in Illinois as a living member of the fauna, it is very abundant in fossil deposits of the last geological period. 40 POLYGYRIDAE Family POLYGYRIDAE To the family Polygyridae belong most of the large snails living in Illinois. The shell in the different species varies from one-fourth inch (5 mm.) to an inch and a half (40 mm.) in diameter and may be either globose or depressed. But in all species the shell of the adult specimen has a reflected outer lip. Many species are provided with denticles or plications on the lip or parietal wall. The young and immature individuals of this family are difficult to identify, because the lip or peristome in young speci- mens is not reflected, as it is in older individuals, and because an umbilicus is present in the young of even those species in which the shell of mature individuals is imperforate. Usually it is safe to assume that immature specimens belong to the same species as the adults with which they are found. The animals of the Polygyridae, though large, are completely retractile within the shell. In color they vary from whitish or cream to blackish or brownish. Usually the head, the long, flexible eye peduncles and the short tentacles are of a darker color than the rest of the body, and the underside of the foot is usually of a lighter color. The body of the animal in some species of the family Polygyridae is conspicuously granulated, and in all species granules of varying sizes are present. The animal of nearly all species of this family has a rather indistinct groove on each side of the body extending from the edge of the shell to the head. In most species the body of the animal is about twice as long as the diameter of the shell. Polygyra palliata, a mem- ber of this family, is pictured on this page. POLYGYRIDAE 4] Genus POLYGYRA Say All members of the family Polygyridae found in Illinois belong to the genus Polygyra, which is not found outside of North America and certain islands of the West Indies. Charac- teristics of the genus are those described for the family Poly- gyridae. The figure on page 40 pictures an Illinois species, Polygyra palliata (Say). The genus Polygyra contains the largest species of land snails inhabiting Illinois and also the largest number of species of any genus found within the state. The conspicuous size and color of the shells make them objects easily seen and eagerly sought by collectors. Key to Species and Varieties 1. Base of shell with umbilical opening; sometimes opening parualy obscured by reflected lip, p. 60....../......... Z Base of shell without umbilical opening; umbilicus com- fee closed by 2 Callus; p. 54... 23.0... ee ee 17 2. Aperture or parietal wall of shell with denticles, p. 44........ 3 Aperture or parietal wall of shell without denticles, p. 48... .13 3. Denticles in aperture only on parietal wall, p. 56........... 4 Denticles in aperture only on outer lip, or on both parietal meme newter Ap e494 ois ic es ae oe slg eM om 8 4. Shell 34 to 1 inch in diameter; large umbilical opening partly covered by widely spreading lower lip; denticle on parietal wall short and narrow.......... thyroidus, p. 56 Shell 4% inch or less in diameter; umbilicus wide, often not partly concealed by lower lip; denticle on parietal wall EMCI ANS tO ee a hep Se we tenis os 5 5. Umbilicus not at all concealed by lower lip.............. a PG oh oats aS ees tridentata untdentata, p. 45 Umbilicus partly concealed by lower lip, p. 61.............. 6 6. Umbilical opening small, a mere slit, almost entirely covered by reflected lower lip............... fraterna fraterna, p. 61 Umbilical opening distinct, only partly covered by reflected Fe Eee a ee ee eer ee eee 7 7. Denticle long; umbilicus round, partly obscured by lower Me a ei. bt, ee oan ons tos Pe fraterna cava, p. 61 Denticle short; umbilicus only very slightly obscured by ME INE ee oc NN aralvs Kova ys ee oes monodon, p. 60 8. Denticles in aperture only on outer lip......... aiyeiage a Cee ee ee eee ee tridentata bidentata, p. 45 Denticles in aperture on both outer lip and parietal wall, A NS easing fy an cetinth o> a oben Saki iceaed Mmmm oasit 9 42 10. ie 12. 13. 14. io: 16. iy. 18. 19. 20. 4 POLYGYRIDAE. Parietal denticle quadrate, but not wider than high, forming a lettet UV... ..2% +4 ap een dorfeuilliana, p. Parietal denticle long, narrow, not forming a letter U, pp. 45, 62; or quadrate and twice as wide as high, p. 46.. Shell less than 14 inch in diameter; umbilicus small, deep, partly closed by reflected lower lip; parietal denticle long, Natrow 2. YS Lets es ee ol leporina,* p. Shell 14 inch in diameter; umbilicus not partly closed by reflected lower lip; parietal denticle quadrate or pyrami- dal, pp, 45,040...+.. 0... D4 «a0 200 err Spire dome shaped; parietal denticle quadrate, twice as wide as high; space between labial denticles as deep as wide. . SMa iekP Re ee eds ane ht ee he os aoe ne fraudulenta, p. Spire flattened; parietal denticle pyramidal, roundly pointed at end; space between labial denticles wider than deep, Pers osc Bhi b Ade eines 3's «ota sr Denticles on outer lip or peristome widely spaced, parietal denticle pointing between them... . tridentata tridentata, p. Denticles on outer lip or peristome not widely spaced, pari- etal denticle pointing to labial denticle................ BAe eee Ee ere en ao ae tridentata frisont, p. Shell: approximately ‘1 inch in diameters.22 oe eee Shell. approximately 4 inch in diameter. 2222002 see Spire encircled by a wide brown band. profunda profunda, p. Spire without a brown band, shell uniformly yellowish... .. Umbilicus narrow, partly concealed by lower lip......... Mckee Che we tiae PSMES, wee Se ee ae Ar thyroidus, p. Umbilicus wide, not at all concealed by lower lip.......... SNe NES Shs cae eect ee Ee profunda efasciata, p. Spire dome shaped; umbilical opening very small and partly concealed by lower lip... = \nca.-... 42k clausa, p. Spire almost flat; umbilicus wide and deep, not at all con- cealed -by lower lip... .a5: 4 ee. tridentata edentilabris, p. Lower lip of shell not: notched, p. 51... 2240 ae Lower lip of shell with a notch in middle, p. 59........... Parietal wall of shell without denticles, p. 51............. Parietal wall.of shell with dentreles,. p. 30:4... 9a0eueeees = Shell with color bands encircling whorls, p. 51............ Shell without color bands encircling whorls.............. Upper and lower margins of aperture almost parallel; shell 1 inch an diameter... ...>.2- multilineata multilineata, p. Upper and lower margins of aperture diverging toward columellar region; shell approximately 1% inch in diameter Ses eRe Cee canna take ote SE multilineata algonquinensis, p. *This species may belong to the genus Lobosculum Pilsbry. 44 62 11 45 .10 POLYGYRIDAE 21, 22. 23. 24. Mee anc or more in diameter... 0/4 ¢a0)¢.. el... ee fewer inch oF less in diameter. .:.... 0... -s ee ee eee Peristome wide and pure white... .a/bolabris albolabris, p. Peristome narrow and pinkish in color. . a/bolabris allent, p. Aperture of shell contracted, three-fourths as high as wide. ME iol sae ae Oe 's el Sa ae pennsylvanica, p. Aperture of shell broad, four-fifths as high as wide, p. 51... Color of shell brownish or chestnut. . mu/tilineata rubra, p. Color of shell yellowish or whitish... .mu/tilineata alba, p. Pemeramerwrtnout denticles, p. 50. 0.22.2 .68 1566s eee es Penstome with 1 or 2 denticles, pp. 4/7, 53.......%2....... Shell 4% inch or less in diameter; parietal denticle long and narrow, extending backward almost to umbilical region. . TIER are Css wo ehnce pie vere eas inflecta edentata, p. Shell approximately 1 inch in diameter; parietal denticle short, not extending backward almost to umbilical region. . Shell convex, much wider than high; parietal denticle only pupa Gevelopegs se) ra oS albolabris dentata, p. Shell globose; parietal denticle well developed, p.50........ Spire depressed-dome shaped; aperture large, round; parietal denticle, short, tubercular in shape............. zaleta, p. Spire elevated-dome shaped; aperture contracted, elongate; parietal denticle long, curved................. elevata, p. ‘Periphery of shell angled or sharply keeled, pp. 52, 53; upper denticle on outer lip large and extending con- Spreuans | y,ifom> peristome;; pr.5o-.--. =F} . which does not seem to close the ; SSE Ie aby aperture when observed from the front view, and in the notch on the lower lip, which is larger and is not centrally placed as it is in stenotrema. The brown shell of hirsuta, also, is more nearly globular in shape and is much more hairy. The hirsute processes of the epidermis are placed in regular rows and stand out from the shell to a considerable distance. This regularity is seen only in fresh, unworn speci- mens, as the hairs are easily rubbed off. The umbilical region is more deeply indented in hirsuta than in stenotrema. The differences between these two closely related species are well shown by the figures in this volume. The animal of hirsuta is whitish, with the head, eye peduncles and tentacles slate colored. The foot is semitransparent and is very narrow when extended. This is one of the commonest and most widely distributed snails in Illinois. Its usual habitat is in forests along river valleys where there is a growth of oak, hickory, elm, basswood and box elder trees. The snail is found under and in old logs, under forest debris and sometimes in the washed up brush and other material deposited by high water. It seems to prefer moist locations, but has been found in some places which are relatively dry. The distribution of hirsuta includes both the United States and Canada. It may be found in Canada and Minnesota, south to Kansas and eastward to New York and Alabama. Polygyra hirsuta was among the first species of land snails described by Thomas Say. Since the original description, pub- lished in 1817, is accurate and very minute, later authors have not improved upon it. Say had a peculiar insight into the details which separate one species from another, and his descriptions are models of accuracy in this respect. 60 POLYGYRIDAE POLYGYRA MONODON (Rackett) The shell of the species Polygyra monodon is small. It rarely exceeds five-sixteenths inch (8 mm.) in diameter and it some- times measures only a little more than one-fourth inch (7 mm.). The dome-shaped spire of monodon has usually 6 closely coiled whorls. The base of the shell appears flattened when viewed from below, and a large round umbilical opening is distinctly present in this species. Just behind the peristome, which is white and rather thick, is a notable constriction of the body whorl. The parietal wall has a short well-marked plait, and the peri- stome has no denticles on it. The color of the shell is brown. No other shell in Illinois could possibly be confused with a shell of monodon, excepting perhaps that of some specimens of Polygyra inflecta edentata, which is com- pletely imperforate, whereas monodon is widely umbilicated. The animal of Polygyra monodon is yellowish brown; darker on the head, eye peduncles and tentacles. The color varies in intensity. This is one of the most abundant snails in Illinois and is found in all suitable localities throughout the state. It is more common in the northern than in the southern part of Illinois. The habitat of Polygyra monodon is in lowlands, usually on the floodplains of rivers and creeks or the margins of lakes, in woodlands of oak, hickory, elm and willow. The animal is some- what gregarious; usually six to a dozen specimens are found together under old logs and in forest debris. The author of this species, T. Rackett, was an English zoologist who lived in the early part of the nineteenth century. He described this species as Helix monodon in 1822. ow A wife, domestic, good and pure Like snail, should keep within her door; But not like snail with silver track, Place all her wealth upon her back. —Wiii1amM Wa tsHam How, Good Wives POLYGYRIDAE 61 POLYGYRA FRATERNA (Say) The brown shell of Polygyra fraterna is usually larger than that of Polygyra monodon, and specimens almost one-half inch (11 mm.) in diameter are not uncommon. An upland species, Polygyra fraterna inhabits forests of oak, elm, hickory and ironwood, on hillsides or on limestone cliffs. Polygyra fraterna fraterna (Say). The typical fraterna, with a shell almost one-half inch (10 mm.) in diameter, differs from Pol- ygyra monodon in having the umbili- cal region almost closed and rather deeply indented, and also in having a heavier and longer parietal plait, as shown in the figure. It is abundant on the bluffs of the Ohio and Mississippi rivers, where monodon is absent. In distribution, fraterna fraterna is more common in the southern than in the northern part of Illinois. Polygyra fraterna cava Pilsbry & Vanatta. The shell of the variety fraterna cava is larger (11 mm.) than that of Polygyra monodon or fraterna fraterna. It is characterized by an indented umbilical region and by a distinct umbilical perforation which is not so wide nor so nearly round as that of monodon. The variety fraterna cava is rare in Illinois. It has been collected only from Jo Daviess, Carroll, Whiteside, McHenry, Menard and Clark counties. It is, therefore, a form of the northern and central parts of the state. The changes of molluscan names and the shifts in their positions in classification are well shown by the history of the monodon-fraterna group of land snails. At one time the small form now known as Polygyra monodon was known as Polygyra leai. Dr. Henry A. Pilsbry indicated that this form was the same as Rackett’s monodon, and that the larger form with the partly closed umbilicus was fraterna. For a long time fraterna was placed as a variety or race of monodon, but it is now con- sidered a distinct species. Like all other snails of wide distribution, for monodon and | fraterna are found from northern United States to Texas, these species have developed several varieties or races, especially in the southern states. 62 POLYGYRIDAE POLYGYRA LEPORINA Gould Sometimes known as Lobosculum leporinum, Polygyra lepo- rina has a shell measuring about one-fourth inch (5-6 mm.) in diameter. It is easily recognized by its small size, small umbilicus, hirsute surface and two denticles on the peristome, which pro- duce a U-shaped notch in the lower part of the lip. The brownish shell has a long, slightly curved plait on the parietal wall. The hirsute surface may be seen only in unworn speci- mens. The only Illinois snail that might be confused with this species is Pol- ygyra hirsuta, but hirsuta lacks the two denticles on the peristome and it has a parietal plait that is different. Polygyra leporina is found in Illi- nois only in the southern half and, with the exception of one record from Clark County, it has been found only in the counties of Randolph, Perry, Jackson, Union, Saline and Hardin. Kentucky, Tennessee, Missouri, Oklahoma and Texas are other states in which Jeporina is found. This snail occurs in woodlands of oak, hickory, elm, iron- wood and hawthorn, usually about midway between top and base of hills. It may be found under debris, on flat-topped rocks, under limestone outcrops and among leaves. In Clark County it has been found in the bottom lands of the Wabash River; in Randolph County on the Mississippi bluff near Chester, the only locality in which it has been observed in the valleys of the great Illinois river systems. This species appears to be a migrant from Kentucky or Missouri, in both of which states it is abundant. The genus Lobosculum was instituted in 1930 by Dr. Henry A. Pilsbry to contain certain small Polygyra-like snails which differ from the true Polygyra in details of anatomy. The species previously known as Polygyra pustula (Ferussac) was made the type of the new genus Lobosculum. The snail described here is the only Illinois species which may possibly be referable to this new genus. BULIMULIDAE 63 Family BULIMULIDAE Snails of the family Bulimulidae have elongated shells which measure from one-half inch to 5 inches (12-130 mm.) in length. Because this family as it is distributed in many parts of the world is predominantly semitropical or tropical it is sparsely represented in temperate climates. In Arizona and Texas several species having shells an inch to an inch and a half in length are found. The one species found in Illinois has a shell that is smaller than the shells of many of the southern species. Genus BULIMULUS Leach Only one genus of the family Bulimulidae is known to occur in Illinois. And of this genus, Bulimulus, only one species is recorded from this state. BULIMULUS DEALBATUS (Say) The ovate shell of Bulimulus dealbatus is less than an inch (19-22 mm.) in length. The spire is elongated, the 6 whorls are rounded and the sutures are deeply indented. The body whorl is very large and relatively ventricose. A large ovate aperture with no denticles of any kind occupies nearly half the length of the shell, and the inner lip or parietal wall forms a flattened expansion which projects over the deep, distinct umbilicus. The shell is white, blotched with ashy streaks and spots, and its walls are relatively thin. This snail is a new member of the record- ed fauna of Illinois. No specimens were known from the state until about 1925. The top of the south end of a Mississippi River elevation known as Fountain Bluff, in Jackson County, is the only known locality in the state where this snail lives. Probably this species is a migrant to Illinois from Missouri, a state in which Bulimulus dealbatus is abundant. Bulimulus dealbatus is a common snail in the southern states, its known distribution being from South Carolina and Alabama west to Oklahoma and Texas. apy \ - <. “AN DaS 64 ZONITIDAE Family ZONITIDAE To the family Zonitidae belong several species of snails having yellowish, horn-colored or hyaline shells with a glassy or shining surface. They vary in size from less than one-sixteenth YW Ss > . > a inch to 1 inch (1.5-26.0 mm.) in diameter. The peristome of the aperture is always simple and sharp, never reflected as is that of the Polygyridae. The surface sculpture is nearly always fine and seldom appears as riblets. The shell at times completely covers the large animal, which, however, is well extended from its horny covering when in loco- motion. The body and foot of the animal are about twice as long as the diameter of the shell. The eye peduncles are long and slender, the tentacles short. The figure illustrates the animal and shell of Mesomphix cupreus, a species of this family. The Nearctic Zonitidae north of Mexico number approxi- mately 135 species and races divided among about 15 genera. Of these, 20 species and varieties, divided among 8 genera, occur in Illinois. Most of the species are restricted to North America but several, among which are Euconulus fulvus and Zonitoides nitidus, are found on three continents. Perhaps no group of American land snails has changed so much in nomenclature during the past 15 years as have the Zonitidae. The student of a decade or more ago would scarcely know the species under the generic names now accepted. These changes have been made necessary by the anatomical studies of such zoologists as Dr. H. A. Pilsbry and Dr. H. B. Baker. These somewhat drastic changes in familiar names of old and well-known species are deplored by some teachers, but the advancement of scientific knowledge has made them necessary. In many cases the changes have been necessary because of errors ZONITIDAE 65 made by previous conchologists. It may be more convenient for some people to use the old names but, since such use would be incorrect at the present time, it is much better to become familiar with the new names and to use them. Key to Genera mes inch OF more in diameter... .....4.1......-.-.%4... 2 mn eaeumOnsor tess iiVdiaMeter. . .-. cc aes Fence ed toes pe a 3 2. Body whorl increasing greatly in diameter, p. 66; aperture round, without callus on. base............ Mesomphix, p. 65 Body whorl not greatly increasing in diameter; aperture lunate, with yellowish callus at base...... Ventridens, p. 81 ee eee re A IHCH I diameter. 2... 2c ks ee he ee ee 4 Seeess tan 5G inch in-drameter...........-...-.-2-505-- 6 4. Body whorl greatly enlarged toward aperture... Retine/la, p. 69 Body whorl not enlarged toward aperture; whorls evenly Me OP cb Blas Oe waa Dla caaipensl Prana tase ip un ils 5 ®. omell with 4 whorls; base rounded.......... Zonitoides, p. 78 Shell with 6 whorls; base flattened......... Paravitrea, p. 73 6. Spire elevated, dome shaped; diameter equal to or less than height; whorls 6; aperture not extending beyond contour PeNaG PS seme | rh) 20.0. 26 i Tt ind GA ee Euconulus, p. 75 Spire flattened; diameter greater than height; whorls 4; aperture extending well beyond contour of whorls, p. 72... .7 7. All whorls increasing regularly in size, last or body whorl not expanding toward aperture; umbilicus deep and round .. eI. . Soo) Ge EGER Bed 1S SIS 4 Hawatia, p. 72 All whorls increasing rapidly in diameter, last whorl notably expanding toward aperture; umbilicus shallow and oval, whorls loosely coiled around it.............. Striatura, p. 77 Genus MESOMPHIX Rafinesque This genus includes the species of the family Zonitidae having the largest shells. In this genus, the aperture as well as the shell itself is relatively large. Key to Species 1. Base of shell smooth and shining, greenish or yellowish colored; upper surface ribbed and brown............... Bis crete Shae ems oeSiicia ys WSLS Pttsae ills perlaevis vulgatus, p. 68 Surface of shell uniform in texture and color above and below. .2 2. Aperture round; interior of aperture violet or purplish. .... Rey re es ae ee et an hm mae eh 8 friabilis, p. 67 Aperture obliquely ovate; interior of aperture pearly....... 0 ASE BE ee ee ee i ee cupreus, p. 66 66 ZONITIDAE MESOMPHIX CUPREUS (Rafinesque) The copper-colored shell of the snail Mesomphix cupreus attains a diameter of about an inch (24 mm.). In specimens from I]linois the height of the shell is approximately two-thirds = of the diameter. The depressed although somewhat dome-shaped spire has 4% whorls. Of these the outermost, or the body whorl, is widely expanded transversely. The base of the shell is rounded and has a deep, though not wide, umbilicus. The transversely ellip- tical aperture, pearly within, has an indistinct bluish-white callus near the edge of the lip. The lustrous shell is of a rich copper or yellow color with shades of green and brown. The animal is black or blue-black in color; the head, neck and eye peduncles are darker than the rest of the body. The base of the foot is whitish. The eye peduncles, which are rather short as compared with the length of the body, are set wide apart. This snail, once known as Zonites fuliginosa and Omphalina cuprea, is abundant in southern Illinois, ranging as far north as Calhoun and Moultrie counties. It is common to abundant along the river valleys, particularly on the limestone bluffs of the Mississippi River. Its most favorable habitat is in forests of oak, elm, hickory, walnut and ironwood in which there is often a sprinkling of pine. Such situations afford a good cover of logs and general forest debris, where snails of the species cupreus may find concealment. Specimens of Illinois Mesomphix cupreus differ from those that occur in Kentucky, Tennessee, Indiana and Ohio in being more globose. The spire of the Kentucky specimens is relatively flat, and the diameter of the shell is almost twice the height. The Illinois shells more nearly resemble the form found in Missouri, Arkansas and Oklahoma. In the Illinois shells the bluish-white callus found just within the lip is not so distinctly marked as in the Kentucky and Tennessee specimens. J/esom- phix cupreus reaches its greatest development in Tennessee, in the Great Smoky Mountain region, where also occur several varieties or races of cupreus which are absent from the Illinois fauna. ZONITIDAE 67 MESOMPHIX FRIABILIS (W. G. Binney) So closely related to Mesomphix cupreus is Mesomphix friabilis that the collector may have difficulty in telling the two apart. However, shells of the two species, each almost 1 inch (24 mm.) in diameter, may be dis- tinguished by certain general char- acteristics. In friabilis the shell is ‘thinner and more brittle than in cupreus. The spire of friabilis is higher, the height of the shell usu- ally being more than two-thirds and sometimes as much as five-sixths its diameter. In friabilis, the aperture is large and round, rather than expanded transversely, and the umbilicus is smaller than that in cupreus. A feature which will usually separate the two species as found in Illinois is that in friabilis the apical or nuclear whorls are hyaline and not eroded, while in cupreus these whorls have the cuticle removed. The color of the friabilis shell is smoky horn with reddish tones near the aperture. The interior of the aperture is violet or purplish. Altogether, this is a handsome shell. Mesomphix friabilis lives in moist localities. It is a rare species in Illinois, and only three places are at present known where it has been found. These locations are on the Wabash River near Mount Carmel in Wabash County, near Athens in Menard County and south of Marion in Williamson County. The animal, which is a bluish-slate color, resembles that of Mesomphix cupreus in form. William G. Binney, writing in 1885 of the snails of North America, remarked upon the presence of friabilis in southern Illinois. ‘““The species belongs to the Interior Regions, but reaches its greatest development in the vicinity of Wabash County, Illinois. I have also received it from Indiana, from the northern and northeastern counties of Kentucky, and from Franklin County, Tennessee.” Though rare in most parts of Illinois, friabilis is abundant in southern Indiana. The finest specimens of this very delicate shell have been collected in Indiana from the cypress swamps in Knox County and from localities in Gibson County, where the shells attain a full inch in diameter. 68 ZONITIDAE MESOMPHIX PERLAEVIS VULGATUS H. B. Baker The shell of Mesomphix perlaevis vulgatus is likely to be confused with shells of Mesomphix cupreus and Mesomphix friabilis. It differs from them in the following particulars. The ss shell is smaller and measures less than an inch (20 mm.) in diame- ter; the body whorl is of relatively less height; and the aperture, con- siderably wider than high, is more transversely elliptical than those of cupreus or friabilis. The base is smooth and shining; the upper sur- face is very finely ribstriate; the umbilicus is almost closed. This shell, of a satin-finish luster, is brown above and greenish or yellowish below. A wide white callus borders the edge of the lip. Mesomphix perlaevis perlaevis is not found in Illinois. The body and foot of the animal are pearly white; the head and eye peduncles are dark blue. 7 The variety Mesomphix perlaevis vulgatus is common to abundant in the hill region of southern I|linois and on the bluffs of the Ohio River. It prefers forests of oak, elm and hickory, with bushes of hawthorn, hazel, gooseberry and sassafras, and vines such as Virginia creeper and poison ivy. It is found under logs and among forest debris. In some of the smaller valleys it can be found under large blocks of stone in gullies, where it has sought concealment and moisture. It is at present known in Illinois only from the counties of Saline, Gallatin, Pope and Hardin. This species was long known under the name Zonites laevi- gata, a figure of which was published in Ferussac’s Natural History of Mollusks. Special inquiries carried on by Dr. H. B. Baker revealed the fact that Ferussac had never described this shell, but had. mistakenly attributed the authorship of the name to the eccentric French naturalist Rafinesque. Zonites laevigata thus becomes what is known as a nude name, not described by anyone. Dr. H. B. Baker in 1933 applied this name to a race of the species perlaevis. A complete revision of the shells form- erly classified under the name Jaevigata has been made by Dr. H. B. Baker in his Check List of Nearctic Zonitidae, published in 1933. ZONITIDAE 69 Genus RETINELLA (Shuttleworth) Fischer Snails of the genus Retinella have small hyaline shells. In none of the species of Retinella does the shell greatly exceed one-fourth inch (6.5 mm.) in diameter. The shells of these snails are glassy and shining; after the animal has been removed, they appear almost as though varnished. They appear black when the animal is present. They range from light brown to creamy white in tint, the color differences pertaining to indi- vidual shells rather than to all the members of a species. Snails of the genus Retinella usually live in woodlands of oak, hickory, maple and elm. Some species are solitary in habit, but the majority live in colonies, and usually a number of speci- mens may be collected from one piece of rotting timber. The four species of Retinella occurring in Illinois may be known from all of the other small species of zonitoids by the presence of regular, radiating impressed lines extending from the suture to the base of the body whorl. The impressed lines are parallel with the growth lines, but are evenly spaced, with growth lines between. The animal of Retinella is bluish or blackish in color. Key to Species 1. Base of shell flattened; umbilical region indented and having wes Sonia PerroratiGn:......'.. - =.=... sk a indentata, p. 71 Base of shell not flattened; distinct umbilical opening, p. 70.. 2 o. Wmpireal -openme elliptical: .... 054.2252. 24 wheatleyi, p. 70 Mmbeeal openme round, p. 10) figc€. o: 27.4... 2. mene. 3 3. Shell with impressed radiating lines widely and regularly SS Re, CE Ie en ey ee eh aes rhoadst, p. 70 Shell with impressed radiating lines close together........ electrina, p. 69 RETINELLA ELECTRINA (Gould) The shell of Retinella electrina, less than one-fourth inch in diameter (5 mm.), is over twice as broad as high. Yellowish in color, it has a shining, glassy surface, upon which the radi- ating impressed lines occur rather close together. The shell has 4 whorls, a rounded base and a round, wide and deep umbilicus, fig. A, page 70. Retinella electrina, also known as Jitrea hammonis and 70 ZONITIDAE Vitrea viridulus, is common under logs and loose bark in some of the large Illinois river valleys and their adjoin- ing ravines. The distribution is spo- radic. SIN PD Pa \ K< a SS =X f. S > § ~ > the variety spiralis may be known by its broad turban-shaped spire, its light brown color and particularly by its parietal lamella, which is very long and makes nearly or almost a full turn of a whorl. The other parietal lamellae are deep seated, also. The basal folds are placed deep within the whorl. The race sfiralis is distinct in its shape and in the position of the parietal lamella. It is known in IIli- nois only from Union County, where it is found in the heavily wooded hill region at Alto Pass. The size is less than one-eighth inch (2.5 mm.) in diameter. This snail was first observed in Logan County, Arkansas, and its previously published localities include only Wyandotte, Indiana, and two localities in Alabama. The Illinois record adds another state to the distribution list. 116 VALLONIIDAE Family VALLONIIDAE Snails belonging to the family Valloniidae are abundant in Illinois, although only one genus of this family, Vallonia, is found in the state. Genus VALLONIA Risso Shells of the genus V’allonia are small in size; none of them exceeds one-eighth inch (2.75 mm.) in diameter, and several are smaller (2.0 mm.). In color most of the shells are waxy white, although some are reddish or brownish. Shells in some species are dull; in others they are shiny or glassy in appearance. Shells in this genus are flattened or only slightly elevated, and in most species the 3% or 4 whorls seem to be coiled in the same plane. This structure, which allows all of the whorls to be seen from the underside, forms a very broad umbilicus. The aperture varies in shape, being either round or oval. The peristome is reflected, as in the large Polygyra snails. The Valloniidae have no folds or lamellae within the aperture. In some species the surface of the shell is covered with thin, membranous ribs which are evenly spaced and stand erect from the surface of the whorls. In other species the surface is marked only by rounded ribs formed by the growth lines. The animal is small in size and yellowish white in color. The cylindrical eye peduncles are not enlarged at the end as in Strobilops; the tentacles are short. When the animal is VALLONIIDAE 117 crawling the edge of the foot is somewhat wavy or crenulated. The figure pictures Vallonia costata. The tiny Vallonia snails found in Illinois live in many diverse habitats, from dry railroad embankments to wet flood- plain areas. They are found in civilization more often than any other Illinois snail and are observed in cellars, in yards of residences and other similar places. Frequently they are found under wet boards in shady places. They are more gregarious than any other Illinois snail, and sometimes hundreds of speci- mens are found in one place. The genus Vallonia divides into two distinct groups. In one group are the species having a shell that is almost smooth and a sculpture consisting of fine lines of growth. In the second group are the species having a shell marked by many erect, more or less equally spaced membranous ribs. Of the species found in Illinois, Vallonia pulchella and Vallonia excentrica belong to the smooth group, and Vallonia costata and Vallonia parvula belong to the costate or ribbed group. The family Valloniidae is an old one and its species are distributed well over the world, including North America, Asia, Europe and northern Africa. It has been introduced into Australia and the Island of Mauritius. Because of their small size, specimens of Valloniidae are often inadvertently trans- ported on greenhouse plants. Key to Species 1. Shell costate, provided with projecting membranous ribs, 0S EL 6 IRI: Seen PPR Stadia Bear emai, ME Beet 2 Shell almost smooth, showing only fine growth lines, p. ter Ue es fae ee ASE ed ee. Sera 3 2. Umbilicus comparatively small; spire slightly elevated.... RE aes Nr Ba secs Me dd we Ao Ge Shel. costata, p. 119 Umbilicus wide; spire not elevated............ paroula, p. 119 3. Shell straw colored; umbilicus ovate because of a rapid ex- pansion near latter half of body whorl..... excentrica, p. 118 Shell clear-glass colored; umbilicus round..... pulchella, p. 118 cw The beetle loves his unpretending track, The snail the house he carries on his back; The far-fetched worm with pleasure would disown The bed we give him though of softest down; A noble instinct; in all kinds the same, All ranks! —Wiii1am Worpsworty, Liderty 118 VALLONIIDAE VALLONIA PULCHELLA (Miller) The shell of the snail Vallonia pulchella is little more than one-sixteenth inch (2.0-2.5 mm.) in diameter. It is a glassy white in color and is almost transparent. The base of the ~ shell and the umbilicus are round. Apparently common in all parts of Illinois, Vallonia pulchella has a va- riety of habitats: floodplain areas of streams in woods of oak and elm; =< isolated woodlands of oak, elm, hick- DD ———= ory, walnut and beech; and railroad Nt), =\))\ embankments, among grass and bushes. ES - Qe NSE Sj In the woods it is found about debris and on wet logs. This snail has a wide distribution outside of North America, including Europe, Asia and northern Africa. It is distributed over most parts of the United States; however, Vallonia pulchella is not found in territory bordering the Pacific Coast. It is said to occur with Vallonia excentrica. A) VALLONIA EXCENTRICA Sterki Slightly smaller than Vallonia pulchella, the shell of Vail- lonia excentrica is about one-sixteenth inch (2 mm.) in diame- ter. It may be recognized by the form of the umbilicus, which is much elongated and very sharply expanded near the last half of the body whorl. The translucent, straw- colored shell as seen from the base is not regularly circular, but is ovate. The name excentrica is given because of these peculiarities. In Illinois, this snail, known as the eccentric Vallonia, has been reported AS \\ only from Champaign County, on the /=SSRY Za Se I KN . \ \ south side of the University of Illinois Ge we SSS in, G4 SS campus and in the yard of Dr. H. J. QZ" (WS Van Cleave, Urbana. It is known U(/) AAS from Europe and parts of America. AAS VALLONIIDAE Hg VALLONIA COSTATA (Miller) The snail Vallonia costata, about the size of Vallonia pul- chella, may be recognized by the series of regularly spaced membranous ribs which mark the surface of the shell and are conspicuous on the body whorl. This whorl angles downward a trifle near ‘ ——— the aperture. The shell of this species Wiss measures over one-sixteenth inch (2.5 ; yyy) , : : * : SS “QGUYf) mm.) in diameter. The spire is flat- : ) tened, and all the whorls are visible in the rounded umbilicus. The aper- ture is rounded, and the white peri- stome is wide and flat. In color the shell is usually gray, but in some speci- mens it is reddish. The costate Vallonia is apparently rare in Illinois and is known from only the northern half of the state. Its usual habitat appears to be on floodplains in river valleys, but specimens have been found on a railroad embankment near Champaign, representing a prairie habitat. Champaign County is the southernmost area from which specimens have been reported. VALLONIA PARVULA Sterki About one-sixteenth inch (1.5-2.0 mm.) in diameter, /allonia parvula has an umbilicus proportionately larger than that of Vallonia costata. The spire is less elevated, and the last whorl does not angle downward so abruptly near the aperture as in costata. The color is a dull waxy white. The Illinois habitats of Vallonia parvula vary from woodlands adjoin- ing small lakes to bluffs of the Ohio and Mississippi rivers. Oak, elm and hickory are the forest trees most usu- ally present in these localities. The species is found on small sticks and on the bark of logs. It has about the same distribution as costata. 120 COCHLICOPIDAE Family COCHLICOPIDAE Shells of the family Cochlicopidae are long, cylindrical, smooth and shining. They are without umbilical openings. Genus COCHLICOPA (Ferussac) Risso The animal of the genus Cochlicopa is blue-black in color, lighter on the foot, which is broad in front and tapering toward the posterior end. The eye peduncles are long and are enlarged at the extremity, but the tentacles are very short. The shell is car- ried partly erect when the animal is in motion as in the above figure of Cochlicopa lubrica. One species and one variety of Cochlicopa live in North America. COCHLICOPA LUBRICA (Muller) With a shell close to one-fourth inch (6 mm.) in length, Cochlicopa lubrica cannot be mistaken for any other species found in Illinois. Its almost cylin- drical form, shining surface and bright horn color at once identify the shell, which has six whorls. The spire is considerably longer than the aperture. This snail is not common in Illinois, and the records are widely scattered. In this state, its habitat is varied. It is found in ravines and isolated woodlands, usually under dead leaves and loose bark of logs. It is distributed through- out the northern part of the United States and also throughout Europe. SUCCINEIDAE 121 Family SUCCINEIDAE The Succineidae, the amber snails, may be recognized by their thin, yellowish, oval shells with very large apertures and small spires. Pictured below is a specimen of Succinea avara. The animal, which cannot retract completely within the shell, is bluntly rounded before, tapering at the posterior extremity. The eye peduncles are short and thick; the tentacles are very short. The body, which varies from yellowish to black, is mottled and streaked. The same animal may be dark colored in spring and yellowish in summer and fall. Genus SUCCINEA Draparnaud The Succineidae family contains but one genus, Succinea, represented in Illinois by five species and six races. Key to Species 1. Aperture round, not much higher than wide, occupying three- Pretererrn Gi Shells... espn ue 8 Pk eh Awd avara, p. 124 Aperture ovate, occupying three-fourths to four-fifths length RR TMER IED, civ ersiaby 2 tgige. gers Noes e: rd nieeela § < Shaye ~ » See B ye 2 2. oa somewhat inflated; aperture ovate; spire broad, ee a OCR, Mie ide ass Dina acs we es aie 3 Shell much elongated, narrow; aperture narrowly ovate; ens OUR eh. Rie Te SINS. ok ele. cee eR y. 5h ek + 3. Aperture regularly ovate; color greenish or yellowish...... naa he Up er ae ae eee eae ag ae eee ovalis, p. 122 Aperture obliquely ovate, expanded at lower part; color Meee ot Bes ds ek PEGS SG e Sorat ott concordialis, p. 123 4. Aperture occupying three-fourths length of shell, little ex- Meee Oe 1OOOE DALE 5 ie oe eens oye + oe pis retusa, p. 125 Aperture occupying four-fifths length of shell, notably ex- Peeateer meetawer Part. . 2. Tone en oss ee ve salleana, p. 127 22, SUCCINEIDAE SUCCINEA OVALIS Say Largest of the Succineidae found in Illinois is Succinea ovalis. Snails of this species live under leaves and other forest debris that affords concealment during the day. However, in wet weather ovalis snails may often be seen on tree trunks at a considerable height (12-15 feet) above the ground, and sometimes even in dry weather they may be found clinging to these high places, the animals having decided to await the next rainy period. Two forms of this species, ovalis ovalis and ovalis optima, are to be found in Illinois. Succinea ovalis ovalis Say. Fig. A. The shell of the typical form, first studied by Thomas Say in Philadelphia, Pennsylvania, is small, not exceeding three-fourths inch (18 mm.) in height. It is wide and the spire is short. The width of the shell is about haH the height. The shell of owalis ovalis may be recog- nized by its oval shape, by its very large aperture, which occupies the greater part of the length, and by the peculiar greenish- yellow color of the shell. The decidedly greenish tint upon the rather thin shell is one of the principal distinguishing charac- teristics of ovalis ovalis. A rare snail in Illinois, Succinea ovalis ovalis apparently occurs only sporadically in the northern part of the state and is rare in the southern portion. Rock Island, Fulton and Brown counties are repre- sented in Illinois collections. Succinea ovalis optima Pilsbry. Fig. B. The large variety ovalis optima, which frequently attains a height of almost 1 inch (22 mm.), is distinguished from the typical form by its somewhat longer spire and particularly by its yellow or amber color, which is very different from the greenish shade of owalis ovalis. The shell is relatively thick, and the surface is marked by coarse sculpture. The long axis of the shell is usually oblique. This variety, the common large Succinea of Illinois, occurs ‘ AN SUCCINEIDAE 123 almost throughout the state. It is apparently more abundant in the northern than in the southern part of IIlinois. The habitat of this amber snail is more often on a floodplain of a river valley than in any other location. Of a dozen known localities in different parts of the state, 10 are in floodplain areas where the forest consists of elm, oak, hickory, willow, sycamore and maple. In a few places, Succinea ovalis optima occurs on upland areas in woodlands where there is abundant shade. SUCCINEA CONCORDIALIS Gould A southern species of Succinea, concordialis is about one-half inch (14 mm.) in height. The color of the shell is a rather deep amber; the apical whorls are somewhat reddish or orange colored. The shell is thin. The body whorl is flattened near the upper part and swollen or sac- like at the lower part. The aper- ture is obliquely ovate, and the columellar region is notably con- cave. This species may be dif- ferentiated from retusa, which it somewhat resembles, by the swollen form of the body whorl and by the reddish apex. Succinea concordialis is known in Illinois from but one locality. A. A. Hinkley has collected it on the bank of the Little Muddy River near Dubois, Washington County, “north of the R. R. bridge on the west side of the embankment.” This species is common in the south, in Louisiana, Alabama and Texas. It is known also from Des Moines, Iowa, where, Pilsbry records, “It lives on the moist earth immediately adjacent to the water’s edge. and where found is usually abundant.” Pictured on this page are two individual variations which occur at Dubois. One is narrow, which is typical, and the other is slightly inflated. The length of the vertical line is the height of the specimen represented by the figure at the left. The figure at the right, representing a specimen which is a variation from the typical shell of Succinea concordialis, is proportionately larger than that of the typical shell. iZA, SUCCINEIDAE SUCCINEA AVARA Say ‘Two varieties of Succinea avara are found in Illinois: the typical avara and the smaller form called avara wardiana. This species, containing the smallest of our Succinea snails, ~ is distributed throughout Illinois wherever suitable localities are found. Varied habitats of these snails include oak, elm, walnut and ironwood in hillside regions; oak, elm, birch, beech and maple in floodplain localities; grass, weeds and low bushes on railroad embankments. Succinea avara avara Say. Fig. A. The shell of Succinea avara avara sometimes approaches one-half inch (9-12 mm.) in height. Usually thin, it is yellow or somewhat greenish in color. It has 3 convex whorls separated by deep sutures. The body whorl is large, but not greatly expanded, and is ovoid in shape, broadly rounded below and somewhat acutely rounded above. The ap- erture is ovate. The spire and aperture are about equal in length. The young shell is usually covered with dirt that adheres to the rough surface. The vertical line represents actual size of the typical shell. The other shell is proportionally smaller. Succinea vermeta of Thomas Say is considered an absolute synonym of avara avara. Say’s description of vermeta was based apparently on an immature shell. In the type locality at New Harmony, Indiana, many variations may be found from one with an almost scalariform spire to one in which the whorls are flatly rounded. In A Catalogue of the Mollusca of Illinois (page 114), Succinea grosvenorii Lea is listed from Canton, Fulton County, on the authority of Nason and Wolf, two Illinois collectors of mollusks. The shells responsible for this listing were incorrectly identified ; they are in reality large specimens of Succinea avara. Succinea avara wardiana Lea. Fig. B. This variety is smaller than the typical avara. The shell, not exceeding a quarter inch (6-7 mm.) in length, is narrower than that of avara avara, and the aperture is more nearly round than that of the typical form. It is found in the habitats indicated for the species. SUCCINEIDAE 125 SUCCINEA RETUSA Lea Unlike most Succinea snails, two species, retusa and salleana, are inhabitants of wet and marshy places, living on partly sub- merged sticks, on water plants, such as cattails, or on wet mud near the margins of streams. The shell of Succinea retusa, usually bright amber in color, has a short spire and a very large and long aperture. Succinea concordialis is the only Illinois species which might be confused with retusa, but con- cordialis usually has a wider shell, and its aperture is obliquely ovate. The animals of Succinea retusa vary in color from yellowish to black, and are more or less mottled or spotted. A curious change in color coincident with the season has been observed in this species, for the animal is dark colored or black in the spring and is of the same amber color as the shell in late summer and autumn. Like many other Illinois land snails, retusa varies consider- ably in form, and several varieties have been named. Succinea retusa retusa Lea. Fig. A. The shell of the typical form is about five-eighths to three-fourths inch (16-20 mm.) in height. It is very fragile, the shell substance being thin. The spire is short and pointed. The aperture, which is narrow and acutely angled above, is long and wide below. It extends about two-thirds the length of the entire shell. The edge of the lip is sharp and thin. The shell has 3 whorls, the first 2 small, the last or body whorl large and elongated. The columellar region is arched, and the parietal wall usually has a light wash of callus. Found in various parts of the state, Succinea retusa retusa has been reported more often from the northern than from the southern half. Succinea retusa magister Pilsbry. Fig. B. The variety retusa magister has a shell which measures about three-fourths inch (18-20 mm.) in height. It is slightly longer than that of retusa retusa. The spire is usually shorter and wider than in the typical form, and the aperture longer and wider. The color is usually lighter than that of retusa retusa, often grayish. At 126 SUCCINEIDAE present retusa magister is known in Illinois only from Rock Island, Cook, Peoria and Fulton counties. Succinea retusa decampi Tryon. Fig. C. The shell of retusa decampi, which is smaller than that of the typical retusa, meas- ures about one-half inch (10-14 mm.) in height. It has 3 whorls, a short spire and a very large aperture. Its principal distinguishing features are its smaller size and its ash-colored shell, which has a margin of dark brown bordering the outer lip and ascend- ing the columellar region as far as the columellar callus. This variety is known in Illinois only from Canton, Fulton County. Succinea retusa illinoisensis Wolf. Fig. D. The variety retusa illinoisensis, about one-half inch (12 mm.) in height, differs from Succinea retusa de- campi in having a longer and more pointed spire with 3 whorls and a shorter aperture. The body whorl of retusa illinoisensis is wider in the middle O) and peculiarly humped or angled, as is evident in comparison of the figures of back views of shells of these two varieties. The color of retusa illi- noisensis is ashy, but the aperture edge is not marked with brown as in retusa decampi. The variety retusa illinoisensis is known in Illinois only from Fulton and White counties. John Wolf, whose name is given as the author of this Swuccinea, did not publish a description of it, and its only record in molluscan literature is in A Catalogue of the Mollusca of Illinois (page 114), where it is listed as a species, Succinea illinoisensis. The speci- mens thought to represent Wolf’s species are from the type locality, Canton, Fulton County, and the use in the present field- book of the name Succinea retusa illinoisensis for a variety which appears recognizable will remove it from the list of nude names. Succinea retusa peoriensis Wolf. Fig E. The amber shell of this small variety is about three-eighths inch (8-11 mm.) in height. Its ovoid shell has an obtuse spire, which is proportion- ally longer than that of most of the other varieties, and a more nearly circular aperture. This variety appears to be rare in SUCCINEIDAE 127 Illinois and is at present known from only four places; however, these represent almost the length of the state. Specimens have been seen from Will, Peoria, Tazewell and Washington counties. SUCCINEA SALLEANA Pfeiffer The shell of Succinea salleana may be distinguished from that of Succinea retusa, which it greatly resembles, by the former’s shorter spire and its longer, wider aperture, which flares more in the lower part than does that of retusa. The columellar region is some- what indented, and the small callus bends around into the upper part of the aperture in a different manner than does that of retusa. Succinea salleana occurs near water, and its handsome, gold-tinted, amber shell attracts immediate attention. Average shells are about five-eighths of an inch (16 mm.) in height. The only specimens at present known from Illinois were collected by Leslie Hu- bricht from Pittsburg Lake, near East St. Louis, St. Clair County, and from Hill Lake, three miles north- west of Columbia, a town that is located in Monroe County. Succinea salleana is a species common in Louisiana, and its presence in Illinois, more than 400 miles north, is one of the perplexing features of distribution. Its abundance at both of the recorded Illinois localities indicates that it has been in the state for a long time and that it has either been overlooked by previous students or else erroneously identified as one of the retusa group. ow January, 1758: Does Mary cough in the night? Two or three snails boiled in her barley-water or tea-water, or what- ever she drinks might be of great service to her; taken in time they have done wonderful cures. She must know nothing of it. They give no manner of taste. It would be best if nobody should know but vourself, and I should imagine six or eight boiled in a quart of water and strained off and put into a bottle, would be a good way, adding a spoonful or two of that to every liquid she takes. They must be fresh done every two or three days, otherwise they grow too thick.—Mary (GRANVILLE) PENDARES DELANEY, Autobiography and Correspondence 128 LIMACIDAE Family LIMACIDAE The snails considered in the preceding pages have spiral shells which are large enough to retain all or nearly all of the contracted animal. However, several species of snails called slugs have little or no external shell. In one family found in Illinois, the Limacidae, a thin, shelly, non-spiral plate of cal- Careous matter acts as a partial protection to the lung. A characteristic of all slugs is the ability of the animal to exude quantities of mucus when it is disturbed. This mucus is so tenacious that with it the animal may suspend itself from a bush or weed and even descend to the ground, much as some caterpillars do with their silken thread. Most of the native slugs found in IlIlinois are small and inconspicuous, but in the states bordering the Pacific Ocean occur several species belonging to the family Arionidae which attain a length of nearly 6 inches. The largest species, Ariolimax columbianus (Gould), is of a greenish yellow color, sometimes with irregular purplish blotches. Philomycus carolinianus, which is very common in Illinois, is the nearest approach in size to this western giant among slugs. In the Limacidae, the long and narrow body is somewhat humped toward the middle and front end, where a rounded projection called the mantle covers the lung region. The eye peduncles are long, rounded and tapering. The tentacles are very short. The body is covered with elongated tubercles sepa- rated by shallow furrows, which are often marked by color lines. The tail or posterior part of the animal tapers to a point; the upper side of the tail is carinated near the end. At the edge of the mantle, near the posterior end, animals of the family Limacidae have a small opening, which is the breathing pore or orifice. The small Limacidae are vegetable feeders, eating decaying vegetation, as well as healthy plants. Genus DEROCERAS Rafinesque The genus Deroceras includes small Limacidae not exceed- ing 2 inches in length. In slugs of this genus, the mantle covers only a small portion of the long, narrow body. Deroceras has long been known under the name 4griolimax, LIMACIDAE 129 given by the German naturalist Morch in 1865, but Deroceras, an earlier name for the same group, proposed by the French naturalist Rafinesque in 1820, must take precedence. Key to Species Upper surface of body covered with flattened tubercles; breath- ine pore with a white border.................¢3. agreste, p. 130 Upper surface of body covered with prominent tubercles; breath- ing pore hot having a white border............... gracile, p. 129 DEROCERAS GRACILE Rafinesque Smallest of Illinois slugs, Deroceras gracile is about an inch (25 mm.) in length when in motion. Although generally gray or yellowish in color, it is sometimes almost black. It is without color spots or markings of any kind. The mantle, which is not much elevated above the general contour of the body, is oval in shape. Distinct, elongated tubercles cover the back of gracile. Its foot is narrow and whitish in color. The mucus of this species is thin and watery. Deroceras gracile, which is widely distributed over Illinois, is the common small slug of forests, fields and cities. In the woods it may be found under loose or started bark, pieces of dead tree limbs, chips, stones and almost any other kind of forest debris. It appears to be solitary in habit, for usually only one specimen is found under one piece of wood, although almost every piece in a given area may contain one of these animals. It is common in towns and cities; here slimy marks, fre- quently seen in the early morning hours, show that gracile has been on a nocturnal hunt for food. It may do considerable damage to truck gardens by eating the tender shoots of plants. It is very fond of lettuce and other succulent plants of this nature. If a garden is infested with these slugs, and they are doing damage, they may be exterminated by fine ashes placed about the plants. Contact with ashes causes the slugs to secrete 130 LIMACIDAE large quantities of mucus, which exhausts them and results in their death. The specific name campestris, bestowed on this small slug by the American conchologist William G. Binney in 1841, must yield to the designation gracile, given by the French naturalist Rafinesque in 1820. DEROCERAS AGRESTE (Linnaeus) The slug Deroceras agreste is larger than Deroceras gracile, attaining a length of 2 inches (5 cm.), although most specimens are about 1% inches (4 cm.) in length. The body of agreste is thicker than that of its smaller relative, the mantle is more prominent, the breathing pore is surrounded by a whitish border and the rugose surface of the tubercles is edged with darker lines. The color of agreste is variable. Some specimens are a uniform gray; others are blackish, whitish, yellow, amber- colored or brown, usually spotted or blotched with irregular black markings. The foot is yellowish-white, and the copious mucus is milky. The agreste slug is believed to have been introduced into the United States from Europe, where it is common. It was first noted in Boston, New York and Philadelphia in the early part of the last century and was then confined to the cities of the seacoast. It is now distributed over much of the eastern and central parts of the United States. In Illinois it has been record- ed from Champaign, Clark, Douglas, Kankakee, McDonough, Mercer, Piatt, Stephenson and Vermilion counties, indicating a rather wide distribution. This slug may do considerable dam- age to garden vegetables if it is present in large numbers. It may be controlled in the same manner as its smaller relative, gracile. A European writer, R. F. Scharff, states that the large slug Limax maximus is a less serious pest in the garden than the smaller slugs of the genus Deroceras, which appear to be especially fond of green plants. PHILOMYCIDAE 13] Family PHILOMYCIDAE The Philomycidae are a family of slugs in which the mantle usually covers three-fourths or more of the length of the body, instead of only the anterior part as in the family Limacidae. The short tentacles of the Philomycidae are placed immediately beneath the relatively short eye peduncles, which have a bulbous termination carrying the eye. The comparatively large breathing orifice is near the anterior extremity of the right side. Beneath the mantle and near the posterior extremity is a rudimentary shell that is connected with the outer surface of the inner mem- brane of the body, but not with the mantle. It is very small (0.5 mm.) in length, irregular in shape, of light horn color, thin and wrinkled. Key to Genera Over 2 inches long; mantle covering entire body. PAilomycus, p. 131 Less than 1 inch long; mantle covering all but anterior one- SMES PIR 2 Se nyayie sie Bes ye sie ee Pallifera, p. 132 Genus PHILOMYCUS Rafinesque The genus Philomycus includes the larger slugs which have the entire body covered by the mantle. This mantle is usually marked with brown and black spots. PHILOMYCUS CAROLINIANUS (Bosc) The slug Philomycus carolinianus is usually 2 to 3 inches (5-8 cm.) in length, although specimens have been found meas- uring 4 inches (10 cm.). The body is subcylindrical and elon- gated. It is flattened and narrowly rounded at the posterior end. The mantle is covered with rough protuberances arranged longitudinally. The back is yellow or whitish, variegated with brown and black spots. These spots form three rather ill-defined Poe PHILOMYCIDAE longitudinal bands down the back and sides of the animal. The long, narrow, whitish foot extends slightly beyond the posterior end of the mantle. Philomycus carolinianus has a wide distribution over Illinois. It is a forest-loving species usually found in moist woodlands under bark that is well started and that allows ample space for the fat body of this slug. A single large prostrate tree trunk may contain as many as 20 specimens of this species, often of many sizes and ages from young to mature. A characteristic of this slug is its habit of excreting an unusual amount of extremely sticky mucus when handled or disturbed. In nearly all books on Mollusca, this slug is known as carolinensis, but the name given to it by its describer is caro- linianus. Genus PALLIFERA Morse The slugs belonging to the genus Pallifera measure less than an inch (20 mm.) in length. Pallifera dorsalis so much resembles Deroceras gracile that the two have no doubt been confused by many students. They are of about the same size, but in Pallifera the mantle covers the posterior three-fourths of the body, while in Deroceras the small mantle covers only the front part of the body above the respiratory organs. Key to Species Body uniformly ashy or dark gray.......... 22.25 dorsalis, p. 132 Body with dark spots on a whitish or flesh-colored ground..... hig MBE, Br eS etl Loess aoe SON Dr fosteri, p. 133 PALLIFERA DORSALIS (Binney) In Illinois, Pallifera dorsalis, less than an inch in length (20 mm.), is ashy or dark gray without color markings. In some other states, however, this species has an interrupted black line extending down the center of the back. The upper surface is covered with rather indistinct furrows separating the glandu- lar projections. The body, narrow and cylindrical, ends in a point. The short eye peduncles are about as long as the neck, termi- PHILOMYCIDAE 133 nating in a small enlargement bearing the eyes. The tentacles are very short. This slug, found over northern and central Illinois, has not yet been recorded from the extreme southern end of the state. The principal counties represented are Lawrence, Clark, Mc- Lean and Carroll. Found in the same habitats as Philomycus, it is often associated with that species. In most works on American Mollusca this species is placed in the genus Tebennophorus or Philomycus. However, in 1864, Professor E. S. Morse established the genus Pallifera, basing it on the peculiar characteristics of the animal’s ribbed jaw. Pallifera is now a well established genus fully recognized by systematic conchologists. PALLIFERA FOSTERI F. C. Baker, New Species The slug Pallifera fosteri is less than an inch in length (20 mm.). It is of much the same form as Pallifera dorsalis, but it is more humped in front and slightly longer in head and ES ae ve Rae eae ‘wane oy yS ae Kono ge ne ve Gores 1 Asi s ect eo. sit ) TS REP 1s v4 v = 3 : : 5 a3 z She ore os oiee “xs ee neck. It may be recognized by the blackish spots on a whitish or flesh-colored mantle. These spéts or blotches may form interrupted, irregular longitudinal lines, especially near the base of the mantle, or irregularly spaced clusters of small dotlike spots scattered over the dorsal surface. In some specimens the black spots form coalescing blotches elongated in form. This species appears to be confined to the southern and central parts of Illinois, Vermilion, Monroe and Wayne counties being represented. 134 PHILOMYCIDAE Pallifera fosteri is often found associated with small speci- mens of Philomycus carolinianus under the same log or started bark, for both species live in the same kind of habitat of oak, maple, beech, elm and hickory. Neither of the Pallifera species described here is so abundant in individuals as is Philomycus carolinianus. A definite method of identifying slugs is by an examination of the horny jaw in the upper part of the mouth. In Philomycus, the jaw is without ribs or plaits and has a strong central pro- jection like a beak. In slugs of the genus Pallifera the jaw has several well-defined ribs or plaits. Pallifera dorsalis has 7 ribs arranged vertically. Pallifera fosteri has usually 4 or 5 ribs placed near the center of the jaw and slanting inwards. Rarely it may have 6 or 3 ribs on the jaw. The genus Pallifera is badly in need of revision. A number of names were given by Rafinesque in 1820 to small slugs of this genus living in the Middle West. One of these names might refer to the species here called fosteri. Because a nameless species is out of place in a handbook and also because this species is common in I]linois, it seems necessary to give it a name, even though in a final revision this new species may fall into syn- onymy because of the discovery of its unity with one of Ra- finesque’s almost unidentifiable names. The types for this new species are from Oakwood, Champaign County: they consist of two specimens, no. 35082, Museum of Natural History, University of Illinois, and were collected by Dr. T. H. Frison and Dr. H. H. Ross. cw The frugal snail, with fore-cast of repose, Carries his house with him, where’er he goes; Peeps out—and if there comes a shower of rain, Retreats to his small domicile amain. Touch but a tip of him, a horn—’tis well— He curls up in his Sanctuary shell. He’s his own landlord, his own tenant; stay Long as he will, he dreads no Quarter Day. Himself he boards and lodges; both invites And feasts himself; sleeps with himself o’nights. He spares the upholsterer trouble to procure Chattels; himself is his own furniture, And his sole riches. Wheresoe’er he roam Knock when you will—he’s sure to be at home. —Cuar.es Lams, The Housekeeper (from VincENT Bourne) ELLOBIIDAE 135 Family ELLOBIIDAE The family Ellobiidae belongs to the suborder Basomma- tophora of the order Pulmonata. Most of the members of this family are classed as marine shells. A few species, like the carychiums, common in Illinois, live far removed from the sea, under forest debris near water or in other moist places. In snails of the family Ellobiidae, the shell is somewhat elongated, the spire long or short and the whorls flatly rounded. In most species the elongated aperture usually has one or more folds on the columella, and frequently it also has folds on the outer lip. Figures on the next page show Carychium shells broken to illustrate the position of lamellae within the shells. Genus CARYCHIUM Muller In the genus Carychium, which contains the only species of the family Ellobiidae present in I]linois, the white, almost trans- lucent animal has on the head a protuber- ance somewhat resembling a snout. ‘The eyes are located on the head at the base of and behind the cylindrical tentacles. The broad foot is blunt before and rounded be- hind. It is unequally divided into a short fore part and a longer hind part. The base of the foot may be seen by inducing the animal to crawl on a pane of glass. The under view of the animal is shown in the small figure. The large figure pictures an animal and shell of the species Carychium exiguum. The tentacles in animals of this genus, as in other animals of this suborder, are con- tractile but not invertible as in the true land snails of the suborder Stylommatophora. Key to Species Surface of shell almost smooth, showing only growth lines NR ce oe wake nee i ec. ie Megs es wana exiguum, p. 136 Surface of shell with vertical striations, as well as growth lines. . oa NEOUS Fe ny eA eg ae Oana CORE Rw Sg ae ge exile, p. 136 136 ELLOBIIDAE CARYCHIUM EXIGUUM (Say) In the species Carychium exiguum the shell measures little more than one-sixteenth inch (1.7 mm.) in length. It is white in color and shining or waxy in texture. It has two lamellae, . one large and the other small, which extend upward spirally along the columellar axis inside the shell as an evenly ascending shelf. The large lamella is conspicuous at the aperture. The smaller lamella, less conspicuous than the large one, re- volves below it. The shell of Carychium exig- uum has 4% relatively inflated whorls. The obliquely oval aper- ture is approximately one-third of the total length. The peristome is thickened and expanded. The shell surface is almost smooth, but shows faintly the growth lines. The records indicate that this species is more abundantly distributed in the northern than in the southern part of Illinois. CARYCHIUM EXILE H. Cisbes The waxy white shell of Carychium exile differs from that of Carychium exiguum in being more slender and elongated. The smaller aperture of exile oc- cupies a little less than one-third the length of its shell. Carychium exile may be distinguished from Carychium exiguum by the sculp- ture of its shell surface, which is noticeably striated vertically. The shell of exile, which measures close to one-sixteenth inch (1.6 mm.) in length, is also a trifle smaller than that of exiguum. The large upper lamella of the columella extends well into the cavity of the body whorl, almost filling it. It is bent sharply downward. Carychium exile is widely distributed over most of Illinois. Land Snails Introduced From Foreign Countries Ao Ne Doers NAci LS [Introduced From Foreign Countries In greenhouses and conservatories a few species of land Mollusca have been found which have accidentally been brought to the United States, usually with plants. In some instances these imported species have spread beyond the confines of green- houses and may be found in yards, cellars and other places in cities. For the sake of completeness, and because many of the imported species are sure to be found at one time or another by students of Illinois land Mollusca, they are described and figured in this fieldbook. Both snails and slugs are numbered among the introduced species. Of the snails with shells the following species have been recorded: Oxychilus cellarium, Oxychilus lucidum and Opeas mauritianum. Of introduced slugs Limax maximus, Limax flavus and Testacella europaea have been recorded. Species of foreign slugs other than those reported will prob- ably be found in Illinois. A common European species, drion circumscriptus Johnston, has recently been reported by A. La Rocque from several places in Canada, notably in Nova Scotia and in Quebec and Ontario, near Ottawa and Toronto. Some years ago it was recorded from near Niagara Falls, and there is no reason why it might not be found in the northern part of the United States. A careful examination of the greenhouses in public parks might bring to light a number of species, not only of slugs but of snails, introduced on imported plants. OXYCHILUS CELLARIUM (Muller) The shell of the European snail Oxychilus cellarium is less than one-half inch (11-12 mm.) in diameter; its height is about half this measurement. It is yellow in color and shining in texture, has a flattened spire showing usually 4 whorls and a rather wide umbilicus. The base is circular and almost flat. The aperture when viewed from the front is obliquely ovate. The animal of this species is black or blue-black in color [132] 140 SPECIES INTRODUCED on the back, sometimes whitish toward the end. The body is long and narrow; the shell is placed well toward the posterior part. The tentacles are short, and the eye peduncles long and slender. In Illinois, cellarium is known only from greenhouses in Chicago and Rockford. This species has been known previously as Zonites cellaria and Vitrea cellaria, as well as Oxychilus cellarius. (| A NAN aN it OXYCHILUS LUCIDUM (Draparnaud) The introduced species Oxychilus lucidum is larger than Oxychilus cellarium and the spire is more nearly flat. The shell of most Jucidum specimens measures about one-half inch (12.5 mm.) in diameter. The body whorl is wide and expanded, which causes the aperture to be wider than high. The base of the shell is more nearly flat and the last whorl and the umbilicus are wider than in cellarium. The shell is of the same yellowish color and shining texture as that of cellarium. Both species of Oxychilus described here are common in Europe. The larger species is known in Illinois only from the greenhouses in Chicago parks. \ \\\ OPEAS MAURITIANUM (Pfeiffer) The small snail Opeas mauritianum, an emigrant from the Island of Mauritius, off the coast of Africa, may be known by its long spire of 7 whorls, its small aper- ture and its yellowish color and shining tex- ture. Specimens of this species vary in size, av- eraging about one-half inch (11.0-12.5 mm.) in length. In Illinois it has been found only in the greenhouses of Chicago parks. SPECIES INTRODUCED 14] LIMAX MAXIMUS Linnaeus The slug Limax maximus was introduced from European countries. It is easily known by its large size, 6 inches (15 cm.) when fully extended. F oD Ra - at lp wces Bens hme Go The body is elongated and subcylindrical and it has a strong carina on the dorsal surface near the posterior end. The surface is covered with elongated tubercles arranged longitudinally. The middle of the back is ashy or light brown with stripes and blotches of black arranged in longitudinal pattern. The sides are lighter in color than the back, and the foot and under parts are dirty white. The large, oval mantle, with tubercles arranged in an irreg- ular concentric pattern, covers about a third of the body at the anterior end. A large respiratory opening is at the posterior margin of the mantle on the right side. The tentacles are short and blunt. The peduncles are rather long and slender, and the eyes are on swellings at the ends. Limax maximus, has a small, silvery-white, rudimentary internal shell about one-half inch (13 mm.) long, shown in the small figure. This shell, which is located beneath the mantle over the respiratory cavity, pro- tects the lung. This large slug is common in many greenhouses in Chicago. At Neoga, Cumberland County, the slug was observed in a well of drinking water in the autumn of 1932. It no doubt has been introduced in other places in Illinois, but records are not known. It is abundant in other parts of the United States. At Rochester, New York, Limax maximus has spread over the city, and at present it may be found in many residence yards. It is common in cellars where there is considerable dampness. It is a voracious eater, and, although its principal food consists of fungi, when in cellars 142 SPECIES INTRODUCED it may do considerable damage by eating vegetables. Meat is often included in its diet, and it has been known to commit cannibalism when several slugs have been confined in a small place. Since it feeds mostly at night, it may be overlooked by the collector. The copious mucus of this slug is very sticky, and flies and other insects soon succumb when covered with the secretion. LIMAX FLAVUS Linnaeus The large European slug Limax flavus measures 3 to 4 inches (8-10 cm.) in length. It is smaller than Limax maximus and differs from it in being somewhat narrower and more Du : Sy fi Ee es i le tee: Par a - oo - TN, be Sores" a vo = - — Se oe ‘< Sod CaF e Pa w > elongated. Its back is brown or yellowish-brown in color and has many oval or oblong spots of grayish color. The mantle is oval, placed near the anterior end, spotted with large rounded blotches and marked by fine, concentric striations. The eye peduncles are long and slender, blue in color and semitrans- parent. The long narrow foot is yellowish white in color. The sides of the body are without spots. Limax flavus has been found in Illinois in the greenhouses of Lincoln Park, Chicago, in company with Limax maximus. Unlike its larger relative maximus, flavus appears to be confined to the greenhouses into which it has been introduced and has not ventured into the territory outside of this protecting habitat, although there is apparently no reason why it should not do so in favorable locations. It does not appear to be so hardy as its larger relative, and perhaps this fact accounts for its failure to spread into cellars and back yards, as maximus has done. SO TESTACELLA EUROPAEA de Roissy The peculiar sluglike mollusk Testacella europaea is the only member of the family Testacellidae to be recorded from Illinois. The animal, which measures 2 to 3 inches (5-8 cm.) in length, SPECIES INTRODUCED 143 bears a small ear-shaped shell near the posterior end of the body. The body is subcylindrical, broad and rounded at the posterior end, tapering gradually toward the anterior end of the animal. The surface of the body is roughened by small folds and furrows. The eye peduncles are rather long and tapering, and the eyes are located at the tip. The tentacles are very short. The mantle is very small and is covered by the shell. The back and sides of the animal are brownish or black, and the base and sides of the foot are light yellow in color. The small, chestnut-brown shell is approximately one-fourth inch (7 mm.) in length, ear-shaped and, in part, spiral. The excavated columellar region of the shell is broad and flat. The surface is roughened by growth lines. The interior of the shell is pearly white. This slug is rare in the United States, and in Illinois it has been recorded only from the greenhouses in Lincoln Park, Chicago, where a few specimens have been found. It is a truly predacious snail in its natural environment, feeding upon worms, other mollusks and even upon members of its own species. It will pursue an earthworm through its subterranean burrows with the persistency and ferocity of a tiger. During the day, Testa- cella europaea hides by burying itself in the ground, often to a considerable depth. It is a common species in the southern part of Europe. It is incorrectly recorded in this country as Testacella halio- toidea or Testacella haliotidea Ferussac; another form of the same name is applied in Europe to a much larger species, 3 to 5 inches (8-13 cm.) in length, known as Testacella haliotoides Lamarck. ei vis. ‘Mors sper epee AE Mala Hasany > a erated els hetrri ne MAS re a PE ii tet — © — ~ ; a c as “wrt > nt ; ' “ ¢ j owes gE j ° par de id » 7 a ee > o ' * ASP i” a: a mae ee y . bahay > 4 goeiaid -" ' ' is . a > J * - ~ > e ‘ * r q ta ig a . — ‘ ‘ j ) same © >! ae . ¥ Pn ln a>¢ r 7 ites Wi SET eg ~artl @4 ys e-paant gaye et een a eed haa” Set oe ‘ Land Snails Of Uncertain Presence in Illinois we ra ee : > Pe Nea NA PTS Of Uncertain Presence in Illinots From certain places in Illinois have been recorded several species of land mollusks not found in collections made by the molluscan survey of 1931-1932 or in any other collections studied by the author of this fieldbook. Since the student may encounter these names in papers on Il\linois mollusks, and par- ticularly since they appear in A Catalogue of the Mollusca of Illinois, published in 1906, it has been deemed important that they be noted and commented upon. Page references below are to the Catalogue. Bifidaria pentodon floridana Dall. Page 112. Known in present literature as Gastrocopta pentodon flori- dana (Dall), this form is found in Florida. The shell upon which the Illinois record is based is believed to be only a slight variation of the typical Gastrocopta pentodon. Pupilla muscorum (Linnaeus). Page 112. This species is listed from Mercer County by Marsh. It has not been found in any collection examined by the author of this fieldbook, and its presence in I]linois is doubtful. It is rare in Michigan and is not recorded from Indiana. Vertigo gouldu Binney. Page 112. This small pupoid is recorded by Hinkley from Rockford, Winnebago County, and by Marsh from Will County. Vertigo gouldii is a northern species, common in Michigan and Minne- sota, but its presence in Illinois is to be strongly doubted. It has not been found in Indiana. Succinea nuttalliana Lea. Page 114. Recorded from Rockford, Winnebago County, by Hinkley and from Fulton County by Wolf, this is a western species inhabiting Oregon and California; hence, its presence in I|linois is to be questioned. The record is without doubt founded on specimens of Succinea retusa, which greatly resemble nuttalliana. L147] 148 SPECIES OF UNCERTAIN PRESENCE Succinea higginsi Bland. Page 114. Described from Put in Bay on Lake Erie, this species was recorded from Rock Island County by Marsh. It is possible that a form of Succinea ovalis might have been mistaken for this species. Succinea aurea Lea. Page 114. This species, recorded from Effingham County by Marsh, is known from Ohio and from Clark County, Indiana. No speci- mens have been seen from IIlinois by the author of this fieldbook. Succinea grosvenorti Lea. Page 114. This species was recorded by Nason and Wolf from Canton, Fulton County. The specimens thought by these men to be grosvenorit are now known to be minor variations of Succinea avara. Polygyra sayti (Binney), same as Polygyra sayana Pilsbry. Page 115. ‘ Recorded from northern I]linois by Calkins and from Edgar County by Marsh, this very distinct species has not been seen in any Illinois collections examined by the author of the present work. It is about three-fourths inch in diameter, has a wide and deep umbilicus and a heavy denticle on the parieta! wall. The records might have been founded on small specimens of the unicolored form of Polygyra profunda. Polygyra sayana has not been recorded from Indiana’and in Michigan is known only from the northern part of the state. It is common in the eastern part of the United States. Polygyra mitchelliana (Lea). Page 117. This Polygyra has been recorded from three counties: from La Salle by Baker and Calkins, from Mercer by Marsh and from Fulton by Strode. No specimens of the true sitchelliana have been seen in any of the material examined by the author of this fieldbook. Several lots labeled under this name proved to be small specimens of Polygyra pennsylvanica. Polygyra mitchelliana may inhabit some part of Illinois not yet examined, for it occurs in Indiana and Michigan. It-is a smaller species than pennsylvanica, which has a heavier shell, a much thicker reflected peristome, a sculpture that is coarse and a surface that SPECIES OF UNCERTAIN PRESENCE 149 is dull, not shining. The aperture is rounded in mitchelliana, while it is transversely narrowed in pennsylvanica. Omphalina inornata (Say). Page 119. Now known as Mesomphix inornatus, this species has been recorded from La Salle County by Calkins. No specimens of this characteristic species have been seen from Illinois by the author of this fieldbook. It occurs in southeastern Indiana. Retinella cryptomphala (Clapp). Two records of this species have been published as from Illinois. Clapp, in Nautilus (Volume 29, page 26, 1915) lists Albion, Edwards County, in the distribution. Hinkley (Nauti- lus, Volume 33, page 15, 1919) lists it from Dubois, Washington County. Specimens from these two places are in the University of Illinois collection, which includes the Edwards County speci- mens upon which Clapp’s record is based. These specimens have a closed umbilicus with a callus, as described by Clapp. There are 150 lots of Retinella indentata in the Illinois collection, embracing approximately a thousand specimens; among these a half dozen individuals have the com- pletely closed umbilicus. In the writer’s opinion, the specimens referred by Clapp and Hinkley to cryptomphala should be referred to indentata as pathologic specimens, unless the cryp- tomphala is simply an indentata with a closed umbilicus. Specimens of the supposed cryptomphala submitted to Dr. Henry A. Pilsbry were referred by him to indentata. No authentic specimens of Retinella cryptomphala have been seen from Illinois. It is common in Tennessee. A shell of the snail Retinella cryptomphala (Clapp), selected from Tennessee specimens, is here figured for reference by Illinois collectors. Vitrina limpida Gould. Page 119. Recorded from La Salle County by Marsh, this is a northern species, living in Michigan and Minnesota. The reference in 150 SPECIES OF UNCERTAIN PRESENCE Illinois literature undoubtedly resulted from a case of mistaken identity. Gastrodonta intertexta (Binney). Page 121. This species is reported from White County by Hinkley and from Vermilion County by Marsh. Curiously enough, all specimens labeled under this name have been found upon exami- nation by the author of this fieldbook to belong to Ventridens ligerus. Ventridens intertextus, as Gastrodonta intertexta is now named, may possibly be found in Illinois, since it is common in Indiana. Gastrodonta gularis (Say). Page 121. Calkins recorded this species, now named Ventridens gularis, from northern Illinois. This record is very doubtful, and authentic material must be found before the species can be admitted to the Illinois fauna. This is a southern species, the only authenticated record north of the Ohio River being from near New Albany, Floyd County, Indiana. . Gastrodonta interna (Say). Page 121. This species is recorded from Macoupin County by Marsh. The record is probably a case of mistaken identity. Gastrodonta interna occurs in southeastern Indiana, and its presence in I[Ili- nois is very doubtful. Bibliography Bel BE POS R AP HY ae literature relating to the study of American land snails is scattered through the proceedings and transactions of many scientific societies and the journals devoted to the study of Mollusca. A few manuals and monographs have been published describing and illustrating species of land snails. Besides references to the more important works, which may supplement the descriptions contained in this fieldbook, mention is made of a few shorter papers. These may be found in some of the large libraries. Baker, Frank Cotutns. 1902. The Mollusca of the Chicago Area. Part II. The Gastropoda. Natural History Survey of the Chi- cago Academy of Sciences Bulletin 3(2). Chicago. Baker, Frank Coruins. 1903. Shells of Land and Water. A Familiar Introduction to the Study of the Mollusks. A.W. Mum- ford, Chicago. Baker, Frank Coriins. 1906. 4 Catalogue of the Mollusca of Illinois. Illinois State Laboratory of Natural History Bulle- tin 7(6):53-136. .Urbana. BakeER, Horace’ Burrinotron. 1925-39. Proceedings of the Academy of Natural Sciences of Philadelphia. (Numerous papers also in the Nauti/us during the same period. Many im- “portant changes in molluscan nomenclature are recorded in these volumes.) Baker, Horace Burrincton. 1933. dA Check List of Nearctic Zonitidae. University of Michigan Museum of Zoology Oc- casional Papers 269. Ann Arbor. Bartscu, Paut, and Mary Exatne Quick. 1926. . “An Anatomic Study of Zonitoides arboreus (Say). Fournal of Agricultural Research 32(8):783-91. Washington, D. C. Binney, Witit1am G. 1885. Manual of American Land Shells. United States National Museum Bulletin 28. Washington, Bee: Binney, WILt1AM G., and THomas BLanp. 1869. Land and Fresh Water Shells of North America. Part I. Pulmonata Geophila. Smithsonian Miscellaneous Collections 194. Washington, DIC: Brarcutey, W.S.,and L. E. Daniers. 1903. ‘On Some Mullusca Known to Occur in Indiana.”” Annual Report for 1902, Depart- ment of Geology and Natural Resources of Indiana 27:577-652. Indianapolis. Brooks, STanLeY T. 1931. A List of the Land Snails of Pennsyl- vania With a Summary of Their Distribution. Carnegie Museum Annals 22(3-4). Pittsburgh. Catt, RicHarp Extitsworrn. 1900. ‘“‘A Descriptive Illustrated Catalogue of the Mollusca of Indiana.” Annual Report for 1899, Department of Geology and Natural Resources of Indiana 24:335-535. Indianapolis. [153] 134 BIBLIOGRAPHY Ciapp, Georce H. 1906. ‘Notes on Carychium and Description of a New Variety.”” Nautilus 19:138-40. DanieEts, L. E. 1903. ‘‘A Check List of Indiana Mollusca.” Annual Report for 1902, Department of Geology and Natural Resources of Indiana 27:629-52. Indianapolis. Dantes, L. E. 1915. ‘“‘A Supplemental Check List of Indiana Mollusca.”. Annual. Report for 1914, Department of Geology and Natural Resources of Indiana 39:318-26. Indianapolis. Forses, Epwarp, and Sytvanus Hantey. 1853. A History of British Mollusca and Their Shells 1. John Van Voorst. London. Foster, THurat Date. 1936. ‘Size of Shell in Land Snails of the Genus Polygyra; With Particular Reference to Major and Minor Varieties.” American Midland Naturalist 17:978-82. Goopricn, Carvin. 1932. The Mollusca of Michigan. Michigan Handbook Series 5. University of Michigan Press. Ann Arbor. Morse, Epwarp S. 1864. “Observations on the Terrestrial Pulmonifera of Maine, Including a Catalogue of All the Species of Terrestrial and Fluviatile Mollusca Known to Inhabit the State.” Journal of the Portland Society of Natural History 1(1):1-60. Pirsspry, Henry Aucustus. 1903. ‘“‘Mollusca of Western Arkan- sas and Adjacent States, With a Revision of Paravitrea.” Proceedings of the Academy of Natural Sciences of Philadelphia: 193-214. Pitspry, Henry Avucustus. 1894-1935. Manual of Conchology. Second Series. Pulmonata. Academy of Natural Sciences of Philadelphia 9 through 28. (This series contains descriptions and figures of many species of land snails inhabiting Illinois. The author cited here has published many other papers relating to American land snails, including Illinois species, in the Pro- ceedings of the Academy of Natural Sciences of Philadelphia since 1889 and in the Nautilus.) Pitssry, H. A., and C. W. Jounson. 1898. “‘A Classified Catalogue with Localities of the Land Shells of America North of Mexico.” The Nautilus 11(4) 1897 to (12) 1898. Reprinted with cor- rections as a separate publication, 35 pages, April, 1898. STERKI, Victor. 1892. “Genus Vallonia Risso.’” In Tryon’s Manual of Conchology, Second Series, 8:247-61. Philadelphia. SterKI, Vicror. 1907. ‘‘A Preliminary Catalogue of the Land and Fresh Water Mollusca of Ohio.’”’ Ohio State Academy of Science 4(8):367—402 (Special Paper 12). Tryon, Georce W. Jr., 1866-67. ‘‘Monograph of the Terrestrial Mollusca of the United States.” American Fournal of Con- chology 2:218-77, 306-27; 3:34—-80, 155-74, 298-324. (Also published by the author in book form.) Van Creave, Harvey J., and THurat Dace Foster. 1937. “The Seasonal Life History of a Land Snail, Polygyra thyroidus (Say). Nautilus 51:50-4. BIBLIOGRAPHY 155 Wacker, Bryant. 1906. ‘‘An Illustrated Catalogue of the Mollusca of Michigan. Part I. Terrestrial Pulmonata (Land Shells).””. State Board of Geological Survey Report for 1905: 431-531. Lansing. Waker, Bryant. 1928. The Terrestrial Shell-Bearing Mollusca of Alabama. University of Michigan Museum of Zoology Mis- cellaneous Publication 18. Ann Arbor. Winstow, Mina L. 1922. Notes on the Internal Lamellae of Carychium. University of Michigan Museum of Zoology Oc- casional Papers 128. Ann Arbor. Winstow, Mina L. 1926. dA Revised Check List of Michigan Mollusca. University of Michigan Museum of Zoology Oc- casional Papers 181. Ann Arbor. The only journal in America for the study of the Mollusca is the Nautilus, published by Dr. H. A. Pilsbry and Dr. H. B. Baker, the Academy of Natural Sciences of Philadelphia. It begins with Volume 3, 1889, and has completed 52 volumes to 1939. Records and notes on many Illinois species of land snails have appeared in its pages; it is considered indispensable for the study of Illinois Mollusca. Pt, ROM Te ivanehe Wiky Mey = Ganesh: Wtesiewes tial Ae eapie iti 1ebies cra: : Rh eh yt Stee: ifs aN EN flat Ob te ag treat bationo” er ay a! at + ead ee ag G5 QELEVAL ty ay ‘pqertnig 14 aed ag ete . } att’. . Ret os sie Pers enaiateli, 6 Valet &, “9, Peg et oh ofa lge ie oi ‘Bre eS oh) sted reve. -S ae Ol SP wal j ; 7) aoe aoa A 7. ~ 4 df 1 SE rT oh 4 aN ed/ Lk owe 2 Dee Pe ee Ae fi) 4 pee Wale A. ye aft as (APoe he : DA ew ut i.) Dae ry di. sitet GR EEK at art 9 Ot oe ‘ > Aico Wsid-ul ¢ halve tel wy ?wi4hs a ae: (Rap cenaultant) [are eha aa i Sy STK wi: é y 4 +R Po? we Ya I =e, _) ws eh} i Tie or ere ih id Ape = & ; j i" * < J 6 ‘ oll , i f a= ¥ e i “oF eS i Pi seemed arate ee Peal As Bee ave ee ees a ee = BT te Ls hal ds Can ere Sa Loup era i ‘fires 1S oe Check List of Illinois Species and Index eeeCck LIST OF ILLINOIS LAND SNAILS EOS LINIIDAUE o cicveiecsta eceunee * 39 Sv Stuy CNV OTSE 8a he ee 25 (BE SeT TG te ea 93, 110 Basommatophora............. 37, 135 bidentata, Polygyra tridentala....... 45 EEA Eis 05k ta oe OR Cae Coe 96 pbentodon floridana............. 147 IESTINNGD2 AMOS 55 > wins cracety ool Bi ae 25 BINNEY, Wicieram G..i% ..).) 2 oes 25 BINOMIAl SYSHEM). 2 soy serie ce ee 19 BY AND LHOMAS. ios jae s sie mabe eee eee Blanks: feld'/data.s «5 sacle. dee eine 12 Body BAM Hoes Gece aes Ie ere 4 OES cere 2152 MARES Bia, ge cae 18 BreaLOiievOniice. . Jesus. f.% oKele sre 4 BOE TMI DID AB iy. =. ice oe rcaeie 63 IBMISINULUS. 0 Pee 3 Coe eie ki atice aee 63 GeGlOalUs: :) i Ai i asa0 sees 18 Food of snails 732). eee ae | Hoots... 22.5 32 Form of ‘shélls) 72 eee 17, 18 FOSTER, THURAY, DADE see 19 fostert Palltfera: 22. 3a ee 133 POWWE97G.. 3. sais dina Aes eae 19, 54 raterna cava, Polygyra. > -42eeee eee 61 fraterna, Power. see eae 61 Polygyra... 2223 eee eee 61 Polysyra fraternad-. 2) +. 61 fraudulenta, Polygyra............-- 46 friabilts, Mesomphizoe a. eee 67 frisoni, Polygyra tridentata. ..17, 18, 45 jultginosa, Zonsteso eee 66 filvus, Euconutlus.2- eee 75 G Gastrocoptd...'; =. 4056 ane eee 34, 94 GPM1f CE == ss oe eee 95 armifera abbreviata............ 97 armiferd Githis...- <2. sss. 96 armifera armijera. - eee 96 armifera svmslts. 32-4 96 contraca. onc eee 94, 97 contracta abruplas...o24e eee 98 coniracta climeana.. 2.25 Gate 98 contracta contratha. =o 5. eee eee 98 COrtiCarta ; .......< <<. eee 101 holzingert <0. 003 G42 eee 19,99 bentodon: ... 26 Sc nk eee 100 pentodon floridana............. 147 pentodon eracths 1....2 .ameee Gee 100 pentodon pentodon............. 100 PIVOCEPE «06 istic nee aoe 102 procera mcclungt........<<=a<005k0e PrOCEYG PKOCETE...wa. omen ee 102 tapPantana.... <.. «ak «eke 101 Gastrodonia:.. . . ...dske eee 81 SUlOriS |. ocx < 19 holzingeri, Gastrocopta........... 19, 99 Eiinbines tor snails.......2.¢.62..< 3 | Tdentityine Snails. ..i....... 0. 0% < 20 Illinois Rorniles Ole. steno 2 see ee 27 land snails, collectors of........ 25 READER SW 2.8 OP fo hy noise eee eo 27 puysiography Of. 2. 66s... 2. oss 26 EUCESHO Le Mets ch a Oe 27 tllinoisensis SARE OED | EE ree oe 126 Succinea retusa. re yea Xs Illustrations, habitat. 5 Eid. CII ee 8, 10, at 24, 28, ‘31, 32 sndentata, Retinella............... a1 tnermis, Helicodiscus singleyanus... 89 inflecta edentata, Polygyra............. 47 BWHECIE. POW EYTO+. «oc. s cs lee 47 menses. PONjgyra.2... i... «soa Se 47 IU PURE ie Sw Sc 4 Gee oe kee 47 POMS ra t8fecla. 6.5.00. ook 47 Infraparietal lamella.............. 110 inornata, Omphalina.............. 149 tnornatus, Mesomphix............. 149 interna, Gastrodonta............... 150 Interparietal lamella... ....5% es 110 intertexta, Gastrodonla.... riB2. 150 interlextus, Ventridens......... 82, 150 J EN Ce MES, Nee aaa ait 5,6 K kawatensts EOAUTARU ah a sa-s)a Ra cio te 72 EV CLASES hears Sin se tars te ree 72 IENNICODD. ROBERT «sic 55... 53's 26 Rrey ais oy h id ch ae ela on, aan een 22 Rocht, ANQutsptra . ... oc cbc wie wise 22, 85 ls IE ADE Sertenetensde cee vere Oa cuchs eo araore 16 Tabral denticle..:.--%)..: ..) Palatal fold.25 2. oe eee 110 palliata, Polygyra. 25 ee eee 40, 52 Pallifert.......2-.ee ae 32 dorsalis 24:4 25.vise ose ee 132 SOStEri .... + ogi oe 133 parallelus, Helicodiscus............ 88 Paravitrea. . <.c.54.a8 ea 73 capsehlé.. +55 5. 2ce ee 73 SiQnifiCONS .. ic. so ee 74 Parietal denticle.....: «. cies s Sis Sele 90 RVCMACHMN, PUNCIUM...002 00500 cca ss 90 Pyramidula PREETI BO a 5 ore 5 ae a cisee ows 84 PIIMPIPEARIMEN SO hires 0 Siclcceiiel eink, mare & 87 SoS POCT = eas BTS eee 85 R Merwin. en ek ils BiG if US tT Ee er en eae 12 Reproduction of snails............ 9 OO UO ee 69 erypiomphala. 3... 0. ec as 71, 149 COREG at OY sage SRE TS aed 69 OT 1 TS a a a ea 71 165 rh fers Ay Reg an eg Ie es) Site o> 70 SU RCTHEL EDS «5 ain abataaiard tik coat 70 relusa decampt, SUucctned......ecesese 126 tllinotsensis, Succtnea.......... 126 TMRALGSIET, SUCCENED s 6, 010.6 ben «wets 125 PeorstenstS, SUCCINEA.......ee00. 126 POLUSE. SUCEVIOED,. 5.3.6 > 20 in geological history........... 30 NAMING... 02sec eee cece ee eees 18 DIESER GI athe ean en 5's sea 15 TEPLOGUCLION OF... 2... ss 2.<< meee 9 WIG SHENG <2 el os. o5 a 5 aint es 3 solitaria, Pyramidula............. 85 SHECICS Oreck Sotnaurcie eS tects, Sem 19, 20 Sphyradium edentulum............ 109 spiralis, Strobilops aenea.......... 115 166 SpPlLCs TMM Lis vie sy bers eee a ee 18 stenotrema, Polygyra........-+2+- 58 CULO ee, BAAN ae oie Wh GUA tsa ee ae 77 milium meridionalis........... Wd PANU AVM. 2 ww ee twee 77 IT OULL LEN Pee AL Ae eee eee Fee 111 ST OULLO US tas re whole eid ne ds oleae oe 111 DEUCteretanal te Dita tiie aie satan thd 114 VETER OCHEM a stag os te ait) s1aca toe a ohare 114 aenea micromphala............ 115 GENCOES DIVAS heed ed oe een 115 OS ITT be One eT ie 113 UAT AYE ors 6 as Se 110, 111 labyrinthica labyrinthica........ 111 labyrinthica parietalis.......... 112 labyrinthtca Wirg0.......+++...-- 112 SLEROBILOPSIDAE.. >.< od ci. 22. 110 E013 | OR i a a ra, OE 26 Stylommatophora.............. 37, 40 NSEC LAT he ee ee A Cis i7t WURE Ween = 2 Se Die ale es ois PROS 148 QUOTE, oa Setnte ee CA ee oe 121, 124 CUOECE CUORG =. cia oleae. He esas 124 QUOTE WOTGLONG... cob eo ses see. 124 CONGOVALGIISL Rah eee ne ae 123 RYOSVENOVIL..... 124, 148 USCIS I: .7 | ee es oe ee 148 SIRMOISENSES 10 es obec 126 MUNLGULONG at eee 147 OUDIISH ee ri ee Ae 122 OUGIES (OPIIMG on aes ee eee 122 QUEUES MOUGLIS® = ark iwhcrnd nrc toe 122 ADELE ce pCR ce ica: athe eee Be 125 retusa decampi........ Bros renee 126 retusa tHimousenstS.........0+.- 126 TEUUSORIN GOS SIEber. tae Lh oe 125 TELUSUEDEOLACH STS 1 hye, ee 126 TLEVUSONELUSE Fo oe ee 125 SULLEEN Ome Ft Pa 127 iD CRIMELOER Tc, ee Ne ees 124 SUCCUMB MOAB 6 ee cee ce 121 STE: op cr rr Serine. Seema 18 SVSLEMeDInomials «so. 0ues ee ees 19 ay eD Meee PRMEEN ‘ok cs ‘hake Eades etc eee 4 tappaniana, Gastrocoplta........... 101 UECRETRODRONUS 1.1.1 ae 133 ACCC NAN ASA, 62.5 00 bao ee 6; 7,18 IMENTAGIER AE... 3x.0cte eee ee Lae 3,4 Testacella CULO DVEG here Wo. ois ae I ne 142 LOMOUGEO So. 3. oe Oe ee 143 halite. a ee 143 tnyrowdes, Polyeyra. . vos... oe 56 thyvordas. Polyegra...0 0 -0cn eens. 56 GUEELUS A wetter Selene Ne cet eee 14, 16 Rete COUR 2 eb ho. ey Fo ee 25 tridentata bidentata, Polygyra............ 45 edentilabris, Polygyra.......... 45 frisoni, Polygyra......... 17, 18, 45 Poly enramen.. Sock See 7,45 Polygyra tridentata............ 45 tridentata, Polygyra............ 45 unidentata, Polygyra........... 45 WEAEIELDS © ciao ar 106 INDEX U Uterens, Hoses oy one 26 Umbilicus., . ii a eee. 18 unidentata, Polygyra tridentata... .. 45 Upper palatal fold 4.505... .:.... \% 93 V Valleys... 2y2eh ee oe 29 Vallonia, . ..2s pda eee ahs COStAIG 3.5: 5 js 116, 117, 119 CXCONIVICE: | ae ee, kee 1 porvala, a3. eee 119 pulchelld, .* nee ee 118 VALLONITIDAE. ee Ss. 116 ventricosa,-V eritgoe. a 105 Ventridens; ..5.¢40 eee ee 81 GEMISEUS 4 is<:6 2 Age oe 82 gulariss: act. See 82, 150 intertextus... .. :cae eee 8&2, 150 ligertis..... ss dager. 81 vermela,, SUCCINEE. .42 ane ee 124 Vertégo. «225 keene 103 ClOhOF . s -vene cad dee 1 SOULE... gan Dee 103, 147 loessensis.: =. .....i.chipt eee 66 lacvigalad iso eg epee 68 ZONITIDAE=. 3-3 22, 64 Zonttoides...... (hae eee 23, 78 GYDOTEMS . 0 5 ss ae 23, 78 Himaiules;.. inca een tee 80 MEnUSCUINS. . <..4'e eee 72 NELETUS .. 5. vivie & etn Ere 79 ZonitoidsS.. v.ue ais ae a =, % _ _—_— a v aa ; ; ; “ tia i = ° "i . . f ‘ * ~ * x ~ 2 ’ f : s a 7 4 7 * me = : 7 he : = stay = = : Maas Hid Bu HES ii} Hid ih SSeS —————=