F I E L D B O O K FRANK COLLINS BAKER ILLINOIS N A T U R A L n { S T O R Y S I) R V E Y MANUAL 2 Natural History Survey Library UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN NAT, HIST. SURV. Digitized by tine Internet Archive in 2010 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/fieldbookofillinOObak Fieldbook of Illinois Land Snails STATE OF ILLINOIS Henry Horner, Governor DEPARTMENT OF REGISTRATION AND EDUCATION John J. Hallihan, Director Fieldbook of Illinois Land Snails By Frank Collins Baker Printed by Authority of the State of Illinois NATURAL HISTORY SURVEY DIVISION Theodore H. Prison, Chief MANUAL 2 Urbana August 1939 STATE OF ILLINOIS Henrv Horner, Governor DEPARTMENT OF REGISTRATION AND EDUCATION John- J. Hallihan, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Jonx J. Hallihan', Chairman William Trelease, D.Sc, LL.D., Biology Henry C. Cowles. Ph.D., D.Sc. Forestry \ViLLi.\M A. XoYES. Ph.D., LL.D., Chem. D. D.Sc, Chemistry Edson S. Basti.v, Ph.D., Geology L. R. HowsoN, B.S.C.E., C.E., En- Arthur Cutts Willard. D.Eng., LL.D. gtneertng President of the University of Illinois NATURAL HISTORY SURVEY DIVISION Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Theodore H. Frisox, Ph.D., Chief SECTION OF ECONOMIC ENTO- MOLOGY W. P. Flint, B.S.. Chief Entomologist C. C. CoMPTON, M.S., Associate Ento- mologist M. D. Farr.\r, Ph.D., Research Ento- mologist J. H. Bigger, B.S., Associate Ento- mologist S. C. Chandler, B.S., Southern Field Entomologist L. H. Shropshire, M.S., Northern Field Entomologist W. E. McCauley, M.S., Assistant Entomologist C. J. Weinm.\n', 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. Rendtorff, M.S., Research Fellow in Entomology K. L. Knight, M.S., Research Fellow in Entomology SECTION OF INSECT SURVEY H. H. Ross, Ph.D., Systematic En- tomologist Carl O. Mohr, Ph.D., Associate En- tomologist, Artist B. D. Burks, Ph.D., Assistant En- tomologist G. T. Riegel, B.S., Assistant Ento- mologist SECTION OF FORESTRY J.\MES E. Davis, ALF., Extension For- ester Lee E. Yeager, Ph.D., Forester SECTION OF AQUATIC BIOLOGY David H. Thompson, Ph.D.. Zoolo- gist George W. Bennett, Ph.D., Limnot- ogist Donald F. Hansen, Ph.D., Assistant Zoologist C. L. Schloemer, Ph.D., Assistant Aquatic Biologist SECTION OF GAME RESEARCH AND MANAGEMENT R.\lph E. Yeatter, Ph.D., Game Specialist C. S. Spooner, Jr., M.S., Junior Bi- ologist SECTION OF WILDLIFE EXPERIMENTAL AREAS Arthur S. H.a.\vkins, M.S.. Game Technician F. C. Bellrose. Jr.. B.S.. Assistant Ga m e Tech n ic ia n COOPERATIVE WILDLIFE RES- TORATION PROGRAM {State Department of Conservation and U. S. Biological Survey) H. G. Anderson, M.S.. Junior 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.. Botar.ist J.C.C.\rter, Ph.D.. Assistant Bota- nist G. H. BoEWE. M.S., Field Botanist SECTION OF PUBLICATIONS T.xMES S. Avars. B.S., Editor (70738— 2M— 1-39) Polygyra muiilineala rubra Buiin.nius Hm>-fersonio il5'.Sc., ChemlUry Biology i't\a«o L. R. HowsoN, B.S.C.E.. C.E.. £m- Arthur Cutts Willard. rWWg.«^»^ gineerins President of the University of Illinois NATURAL HISTORY SU»VB>Yto»-w> Prison, Ph.D., C/iie/ SECTION OF ECONOMIC ENTO- MOLOGY W. r- F;.iNi B S ' ■'omologist SECTION OF AQUA^BWLOGY David H. Thompson, P .D . /■.."- gts- nlo- / Ay George W. Bennett, Ph.D.. Limnol^ agist Donald P. H.\nsen, Ph.D.. Assistant Zoologist C. L Schloe.mer. Ph.D.. Assistant .Iquatir Biologist SECTION OF GAME RESEARCH ti)o>»\* J«t«5?«1?i A N AG E M 5 NT rn VtATTKK, Ph.D., Gam,- :.-t ,, . . . . uNER. JP.. M.S.. yM»l/or Bl- oiogist SECTION OF WILDLIFE EXPEFl MENTAL AREAS ARTfr R S. HAu1^*{>"^.«5r?»t)9^.- Tei intcian F. C. Bellrose. Jr.. B.S.. Assistant Giirnt Tcchniian ^fJ^^T^' - . COOPE irt Eniomology t»X»«»»n **A^«p^^- NiGHT, M.S.. Research Felloic' uomology TION PROGRAM [State Def-:rtmev: oj Conservaiion and U. S. Biological Survey) H. G. Anderson. M.S.. Junior Bi- ologist Louis G. Bri^wn, B.S., Junior Bt - R. E. Hesselschwerdt. B.A. Jum <■ Bioloiiist SECTION OF APPLIED BOTANY AND PLAiNT PATHOi»#<*W o'<^x:Vo*l .^... Assistant /./jfc^* o-'i^i-W*! KHON.-Ph.D.. Botantst .1. C Carter. Ph.D.. Assistant Bota- SECTION OF FORESTRY , "'/' w^ .,„ I n r^ nr -^ r^ G. H. BoEWK. M.S., Field Botamst ester SECTION OF PUBLICATIONS Lee E. Yeager. Ph.D., Forestrr I.\Mh> S. Ayak>. B.S.. t.;, •'■ SECTION OF INSECT SURVEY H. H. Ross. Ph.D . Systematic En- lomologist Cari, O. Mohr. Ph.D., Associate En- tomologist, Artist B. D. Burks, Ph.D.. Assistant /■>;- G. T^RtEc.Ei.; B.S mologi^l (70738— 2 M— 1-39 = << fi^si^v^ FOREWORD THIS 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 MoUusca, 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 servic-es 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 -naterial 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 field- book, therefore, embodies all the present state of knowledge concerning the number of Illinois 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 Illinois 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, w^ll 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 Jfild 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. Prison Chief XJrbana January 16, 1939 ACKNOWLEDGMENTS ACKNOWLEDGMENT is made to Dr. Henry A. Pilsbry, y~V Curator of the Department of MoUusca 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 of 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 Collixs Baker CONTENTS Land Snails: What Thev Are and Where Thev Live 3 P'ood and Feeding Habits of Snails 5 How Snails Reproduce 9 Where Land Snails Live 9 Collecting Land Snails 11 Apparatus tor the Collector 13 Preserving Specimens 15 Labels and Cabinets 16 Classification of Land Snails 17 How to Identify Land Shells 20 Economic Importance ot Land Snails 23 Collectors of Illinois Land Snails 25 Physiography of Illinois 26 Mollusks in Geological History 30 The Land Snail Fauna of Illinois 33 Land Snails Native to Illinois 37 Class Gastropoda 37 Order Prosobranchiata 39 Family Helicinidae 39 Order Pulmonata 40 Suborder Stylommatophora 40 Family Polygyridae 40 Family Bulimulidae 63 Family Zonitidae 64 Family Endodontidae 83 Family Haplotrematidae 91 Family Pupillidae 93 Family Strobilopsidae 110 Family Valloniidae 116 Family Cochlicopidae 120 Family Succineidae 121 Family Limacidae 128 Family Philomycidae 131 Suborder Basommatophora 135 Family PUlobiidae 135 Land Snails Introduced From Foreign Countries 139 Species With Shells 139 Introduced Slugs 141 Land Snails of Uncertain Presence in Illinois 147 Bibliography 153 Check. List of Illinois Species 159 Index 161 xi Land Snails What they are and where they live LAND SNAILS What they are and where they live Among the beautiful pictures That hang on Memory's wall, Is one ot a dim old forest That seemeth best of all. — Alice Cary, Pictures of Memory WHO 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 ot 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 awav. 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 sjjail^ fig. 1, now just emerging from its shell 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 back of the animal and is tilted somewhat to the left side. At the head end of the animal are two pairs oi 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 constantlv moving about, touching everv obstacle in the path [3] ILLINOIS NATURAL HISTORY SURVEY MANUAL of the snaiL If a long eye peduncle is 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 bod\\ which ends in a slender, tapering tail^ is long- and narrow. Irregular granulations that cover the body give it a rough appearance. The underside ot the body, known as the/oo/, is 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 Eye Peduncle Eye Head Tentacle Fig. 1. — Animal of land snail, Polygyra albolabris (Say the body are indicated. Parts oT up and setting down of the foot but by a sliding movement produced by a wave of muscular contractions along the toot. 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 ot 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 ot 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 bodv, 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 ot the bark which is loose or started. On the inner side of this bark we BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 5 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. Lender our log we find one apparently without a shell. This is known as a slug^ 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. Onlv 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 \\oxr\y 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 mav 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 ot 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- 14 13 12 11 10 Fig. 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 ot mucus glands; 11, posterior cartilage muscles; 12, cartilage; 13, lower lip; 14, anterior cartilage muscles. plete half rows of the teeth on the radula of a snail are shown in fig. 3. These are, of course, greatly magnified. Some ot 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/yg\Ta 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 ot the land snail Haplotrema BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 7 concaviim^ shown in fig. 6. This snail has l>ut 51 teeth in a row and only 11 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 Fig. 3. — Two rows of teeth from the left side of a radula membrane ot Polygyra tridentata (Say). Reflected Portion Side Cusps Lateral Tooth Cutting Point Middle Cusp Cutting Point Cutting Point Base of attachment to radula Base OF ATTACHMENT TO RADULA -Cutting Point Median Tooth Marginal Tooth Fig. 4. — The three kinds of teeth, lateral, median and marginal, on the radula or lingual ribbon ot a land snail, greatly magnified. Pig. 5. — Longitudinal section ot the radula of a land snail. The teeth lie on the radula membrane much as shingles lie on a root. Fig. 6. — Teeth trom the radula or lingual ribbon of the carnivorous snail Haplotrema concavum (Say). to discuss the subject ot 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 — c -S ii 'Z 50 ■y. >, o o 3 bO "^ C , - 15 ^ — 50 3 ti C4 Oh O o BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 9 the fruit of the horsetail are often part of their diet. They will not eat pungent plants ot any kind. Not all snails eat vegetable matter. A few are carnivorous and teed upon earthworms, leeches or other snails. Because the body ot the land snail is peculiarly shaped to ht into the coiled shell, the digestive, circulatory, locomotor, nervous and reproductive organs are not so easily recognized and studied as those ot 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 lite 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 lite of anv kind. Forested river valleys are perhaps the most favorable habitats tor 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 o c ^ 5 3 t C 55 I:; I. >. ^ BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 1 I available in quantities; areas where granitic or volcanic rock abounds are usually poor places for snails. Often, isolated wood- lands in the midst ot 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 ot 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 ot the genus Succinea, live among cattails bordering ponds and streams and may be 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. \o 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 manv 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 mav usuallv 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 bv finding species hitherto unknown in his vicinity. 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 tor establishing a record of the presence ot 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 tor the student to keep a record of his field observations in a book or on sheets of paper, which may be called field data blanks. This record should give the exact location of the place where each specimen is found, the nature of the habitat, the kinds ot trees and other vegetation in the immediate vicinity, the condition ot the ground where the collection is made, the nature ot the weather at the time and the temperature ot 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 if 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 taithtully will reward the conchologist with a lull account of his season's work. Apparatus for the Collector Apparatus tor 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 tor those specimens that are desired only tor 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 torceps or tweezers is indispensable for picking up small specimens like the pupoids and also for sorting the collection at home. The points ot 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 ot the zonitoids. It is a o;ood plan to tie a string to the tweezers to prevent loss when thev 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 ot 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 knite is necessary tor the purpose of tearing off small pieces ot bark, turning over debris and digging snails out ot their burrows in the ground. A trowel is often helpful for digging up the earth in favorable habitats. A very convenient implement tor the collector is the Ferriss hoe, made by filing an ordinarv hoe blade into heart-shaped torm. This may be used tor protection against venomous snakes — rattlers, moccasins and copperheads — common in some parts ot southern Illinois, and also for pulling over rock piles and digging up torest debris. To collectors who mav be affected by poison ivy, this implement will be tound ot great value for pulling aside the vines when they cover the ground or old stumps and logs. The snail collector should be caretul to avoid ruthless destruction of the habitats where he is studying. He will notice -J ^^ ^^ The animal is large, light red- %^-^ :...:.■■-.: L^P'^i.=-^^^^^^^\ dish-brown in color and it has ^^^^^^^^^^^^^^yW ) smoke-colored eye peduncles and ^^^~~2^~~^^^^ tentacles. In its geographic distribution profunda is confined to the northern part of Illinois. Although it is abundant wherever found, no living specimens have been seen south of Fulton County. Its usual habitat is in moist woodlands of oak, hickory and birch where there is an abun- dance of fallen timber. In past ages, this species lived in southern Illinois, and the bleached shells are often found in fossil deposits. Several varieties, distinguished by color differences, occur in this species. Only one variety besides the typical is found in Illinois. Polygyra profunda profunda (Say). The shell of the typical profunda is distinguished by a wide brown band just above the periphery of the body whorl and smaller brown bands on the base of the shell and on the spire whorls above the wide band. A shell of this variety is illustrated by the figure. Polygyra profunda efasciata Walker. The color bands are not developed in this variety, as they are in the typical profunda, and the shell is .uniform yellowish horn. About one specimen in every six of this species in Illinois belongs to this variety. "The snail," say the Hindoos, "sees nothing but his own shell, and thinks it is the grandest place in the Universe." — Sidney Smith, Peter Plywley Letters POLYGYRIDAE 49 POLYGYRA ALBOLABRIS (Say! The common white-lipped snail is one of the largest found in Illinois, and shell specimens measuring P/4 inches (27-33 mm.) in diameter are not uncommon. It is imperforate, of a uniform yellowish-horn color and has a spire that is dome shaped. The aperture is usually without denticulations, and the wide and rather heavy peristome forms a flattened expansion bordering the aperture. The shell of this species has 5V2 whorls. The animal is variable in color, shading from cream on the body to gray, black or brown on the head. This fine species of land snail is found in all parts of Illinois, although the localities are rather widely separated. In habitat the species seems to prefer forests of oak, hickory, elm and walnut where there is a forest debris of long accumulation. Polygyra albolabris albolabris (Say). In the shell of the typical variety, shown in the figure, the spire is high and the peristome is wide and flattened. The surface is dull. This variety is found mostly in the northern part of the state, north of Vermilion County. The white-lipped snail is subject to con- siderable variation from the typical, some of which appears to be coincident with geographic distribution. The variations are noted below. Polygyra albolabris alleni (Wetherby). The spire of this variety is more depressed than that of the typical form, and the peristome is narrower and inclined to be rounded. The surface is shining, almost polished in some specimens. The lower part of the peristome has a prominent denticle or callus w^hich is not so conspicuously developed in the typical form. This variety is confined to the southern part of Illinois and has not been seen north of Clark County. Polygyra albolabris deutata (Tryon). This unimportant variety has a shell about an inch (27 mm.) in diameter. It is distinguished by having a small denticle on the parietal wall. The variety dentata is very rare in Illinois and has been recorded only from Cook County in the northern part of the state and from Williamson County in the southern part. 50 POLYGYRIDAE POLYGYRA ZALETA (Binney) The common Polygyra zaleta greatly resembles the white- lipped snail, Polygyra albolabris, and particularly the variety dentata. Its horn-colored shell is much more globose than that of albolabris, which is wider than it is high. The species zaleta has also a distinct, rather mas- sive denticle on the parietal wall which is absent in albolabris al- bolabris and only very feebly de- veloped in albolabris dentata. The shape of the shell and the parietal denticle separate the two species zaleta and albolabris. The only variation among individuals of the species zaleta in Illinois is in the size of the shell, the extremes of which are less than 1 inch and more than 1% inches (24 and 29 mm.)- This variation, however, occurs in the same colony and is to ie considered simply variation in different individuals. The animal resembles that of albolabris in form. It is grayish-brown or blackish in general color, lighter near the foot and at the posterior end. The eye peduncles are long, slender and black. The animal is never so light colored as that of albolabris. Polygyra zaleta is widely distributed over Illinois and, as with Polygyra albolabris, this distribution is very sporadic. It is most abundant in the eastern and southern parts of the state, where it lives in ravines of the smaller river tributaries as well as on the bluffs of the larger rivers. It prefers regions of oak, elm and hickory where there is much debris on the ground. Singularly, the species is not known in the Mississippi Valley north of Calhoun County. This species was once named Polygyra exoleta Binney. as explained by William G. Binney. "When Dr. Binney (Dr. Amos Binney, father of William G. Binney) published the first description of this snail, in 1837. he adopted, without examina- tion, the name zaleta, which he found applied to it in some cabinets, and which he then supposed had been applied by Mr. Say. Finding no description of it, he subsequently applied the name, exoleta, originally suggested, no doubt, by the idea that the species is an old, or superannuated form of albolabris.'' >OLYGYRIDAE 51 POLYGYRA MULTILINEATA (Say) Most specimens of Polygyra multilitieata have dark brown jands on a horn-colored background. The field records indicate :hat Polygyra multilirieata is more abundant in northern than n southern Illinois; nevertheless, oiiie of the finest specimens have iecn collected near Cairo. Alex- iiuler County. This Polygyra is isually found along the edges of ^wamps, in low ground subject :o overflow or in damp woods of Dak. hickory, box elder, tamarack, maple or cottonwood. The animal is generally black- ish, but with granules which are whitish; darker zones lie between the granules. The under part of the foot is black. Several varieties of multiline- ata are known. Polygyra multilineata multilineata (Say). Fig. A. The shell of the typical variety is about an inch (23-28 mm.) in diameter. The bands nearest the periphery are widest. Polygyra multilineata algonquinensis Nason. Fig. B. The shell of this variety is a little more than one-half inch (16-18 mm.), slightly more than half as large as the usual size of multilineata multilineata. In some specimens the color bands are distinct and in others the shell is almost devoid of color orna- mentation. The umbilical region is rather deeply impressed, and in many specimens there is a little slit or chink behind the reflected lip which forms a false umbilicus. The aperture of this variety is not so nearly round as that of the typical form. It is known in Illinois from McHenry, Kane and Cook counties. It was discovered near Algonquin, Illinois. Polygyra multilineata alba and rubra Witter. These are color variations, shells of the first being whitish or yellowish and those of the second reddish or brownish; both are without color bands of any kind. Each has a shell about three-fourths inch (20 mm.) in diameter. The rubra form is common in Illinois, but the alba form is rare in this state. ^ 52 POLYGYRIDAEt i POLYGYRA PALL I ATA (Say) The species Polygyra paUiata is a rather large snail whose shell, when mature, usually attains a diameter of nearly an inch (21-22 mm.). The shell is of a uniform yellowish-brown colorJj and its surface is covered with* short, stiff hairs. It has 5 whorls. The spire of Polygyra palUata is less elevated than is that of many other species of Polygyra, and the periphery, or outermost edge of the shell circle, is marked by a rather distinct ridge or carina. The umbilicus is closed, and the peristome, which is widely reflected, has a distinct labial denticle and a smaller, less distinct peristomal denticle. A long, curved plait on the parietal wall extends backward to the callus, closing the umbilical region. The denticles in the aperture of Polygyra palliata are white. The animal (see page 40) is of a uniform slate color over the upper surface and of a somewhat lighter color beneath. It appears to be much too large for the shell. This snail, which is probably an emigrant from Indiana, where it is common in places, is very rare in Illinois. At present it has been reported from only White and Wabash counties, where it has been found in forests of oak and hickory along the floodplain of the Wabash River. Dr. Henry A. Pilsbry raises the question as to whether Polygyra palliata is distinct from Polygyra obstricta. He writes, "While P. palliata occupies an area generally north of that of P. obstricta there is a broad belt of territory common to the two, in some parts of which intergradation takes place, or, in other words, remnants of a variable, undiliFerentiated, parent race still exist." It would be of interest it similar series of shells could be found in the overlapping area of distribution occupied by these two species. Snails were used in love divinations; they were set to crawl on the he.irth, and were thought to mark in the ashes the initials ot the lover's name. On the subject ot these divi- nations there is a most curious passage in the third Idyl ot Theocritus. — W. Carew Hazlitt, Faiths and Folklore OLYGYRIDAE 53 POLYGYRA OBSTRICTA (Say) The brown shell of Polygyra ohstricta, about an inch In diam- ter (20-22 mm.), differs from that of Polygyra palliata in hav- tig a flatter spire and a carina which is sharp and keellike at the leriphery, as though pinched \ ith the fingers. The surface if ohstricta, unlike that of palli- (^'^^ «»wnw>TM«j 'ta, is not covered with hairlike processes of the epidermis. The lenticulation in the aperture is ihout the same in both species. Animals of these species are similar in color, size and shape. Polygyra obstricta is probably the rarest species of land snail n Illinois and is known only from the valley of Big Creek, in riark County, a tributary of the Wabash River. The ravine n which it was collected is forested with oak, elm, hickory and ;ome sycamore, and the ground is plentifully supplied with old ogs and other forest debris, Polygyra obstricta is also rare in ndiana, its nearest locality in that state being Posey County. Son.ie years ago the late L. E. Daniels, a careful conchologi- :al student of Indiana Mollusca. collected a series of Polygyra jbstricta which shows a remarkable relationship between ob- stricta and palliata, two species usually markedly distinct. These were submitted to Dr. Henry A. Pilsbry who commented on them as follows: "A series of 18 specimens from Grand Chain, Posey County, taken by Mr. Daniels in bottom land near the Wabash River, and in its floodplain shows a complete series of transitions from palliata to obstricta. These supposed species have been separated not only on account of the acute keel of obstricta, and its absence in palliata, but more because of the rough epidermis of the latter. This series, as far as I can see. >hows intergradation in the development of the cuticular proc- esses, as well as in the contour of the shell. "A few of the specimens agree almost exactly with Say's type specimen of palliata, the periphery being moderately angu- lar, the angle disappearing on the last third or fourth of the whorl; and the surface, besides having low, coarse striae, bears numerous cuticular asperities, as though a loose cuticle had been pinched up into many little points, and more or less wrinkled in consequence between them." 54 POLYGYRIDAE POLYGYRA APPRESSA (Say) Usually about one-half to three-fourths inch (15-21 mm.) in diameter, the depressed, horn-colored shell of Polygyra appressa is almost twice as wide as high. The umbilicus is covered by a callus. The shell, which has 5 whorls, is marked by a well-developed plait or denticle! on the parietal wall and a very small denticle on the peristome. In the form of the aperture, appressa somewhat resembles three other species of Polygyra found in Illinois: these are tri- dentata, palliata and fosteri. Polygyra appressa is rare in the northern part of Illinois and has not been seen from the region north of La Salle and Will counties. It is most abundant in the southern part of the state on the bluffs in the Ohio, Wabash and Mississippi valleys. POLYGYRA FOSTERI F. C. Baker The horn-colored Polygyra fosteri shell, over one-half inch (15 mm.) in diameter, is characterized by a long, curved, rather heavy plait on the parietal wall and a relatively large labial denticle. These features very readily separate fosteri from Pol\gyra ap- pressa, for in appressa the plait on the parietal wall is small, short and almost straight, and the peristome is marked by only a slight ridge on the lower part of the outer lip. There are anatomical differences between the animals of fosteri and appressa. Polygyra fosteri is the common appressa-Wkt shell on the limestone bluffs of the Ohio and Mississippi rivers. It is inter- esting to note that the great naturalist Thomas Say distinguished this shell more than a hundred years ago (1821), calling it var. a. The name Polygyra fosteri was published in October, 1932, in the conchological monthly periodical, the Nautilus. POLYGYRIDAE 55 POLYGYRA ELEVATA (Say) This species of Polygyra has been called elcvata because of the very high spire characteristic of its shell. This shell has 6 full whorls, a greater number than is found in many of the larger snails. Aside from the large yellowish spire standing up like a beehive, the most noticeable feature of elcvata is the heavy, tonguelike denticle on the parietal wall. The shell has also a small indistinct swelling on the lower part of the peristome. The size of this shell has been found to vary consider- ably, from three-fourths inch to about an inch (19-25 mm.) in diameter, but all sizes may and do occur in the same colony. The animal is light brown on the upper surface and lighter on the sides and the posterior part. This snail with the elevated shell is most abundant in ravines where there is a heavy growth of oak, maple, hickory or sycamore trees and a considerable cover of forest debris. It is very plentiful wherever it is found, but it is at present known in Illinois only from Fulton, Vermilion, Clark, Lawrence, Madison, Jackson and Alexander counties. POLYGYRA PENNSYLVANICA (Green) The yellowish shell of Polygyra pennsylvanica, about three- fourths inch (16-20 mm.) in diameter, appears to be almost a miniature example of the species Polygyra elevata. Both have a high spire and are imperforate, but pennsylvanica lacks the heavy denticle on the parietal wall and it has no denticles on the peristome. The animal is lead colored, with the under part of the foot a lighter color. This species is widely distrib- uted over Illinois and is found in the same habitats as Polygyra elcvata: in ravines where there is a heavy growth of oak, maple, hickorv or svcamore trees. 56 POLYGYRIDAE POLYGYRA THYROIDUS (Say) A snail with a horn-colored shell, often about an inch (20-25 mm.) in diameter, Polygyra thyroidus may be recognized by the distinctly open umbilicus and the wide, flaring peristome. The majority of specimens have a rather distinct denticle on the parietal wall, but this denticle is absent in many individuals. The characteristics noted will distin- guish thyroidus from any other snail found in Illinois. A notable feature of thyroidus is the great variation in size (15-30 mm.). This may occur in the same colony, or one colony may consist of large individuals and another of small specimens. The largest specimen collected in Illinois measures over 1% inches (29 mm.) and the smallest about five-eighths inch (16 mm.) Studies of Illinois thyroidus made by Dr. Thural Dale Foster indicate that the size variation occurs in all material examined, and also that the absence or presence of the parietal tooth is simply an individual variation which cannot be used in classification. The animal is grayish or yellowish-white with eye peduncles darker in color. The underside of the foot is a dirty white. This snail is found over most parts of Illinois but is appar- ently not common in the extreme northern portion. Its most favorable habitat is on the floodplains of the larger river valleys in woods of oak, elm, beech, hickory and willow. In these places there is usually an abundance of fallen timber rotting on the ground, and a large amount of debris which affords shelter for the snails. On humid days, the snails may often be seen crawling over the ground, over logs or even on standing trees several feet from the ground. The name here used, thyroidus, is given the original spelling applied by Thomas Say in 1817 in the Journal of the Phila- delphia Academy of Natural Sciences. Say later used the same spelling in his American Conchology. Subsequent authors have used the spelling thyroides, which is probably etymologically correct, but, since Say has used the original spelling in several places, later authorities have no right to introduce a different spelling. POLYGYRIDAE 57 POLYGYRA CLAUSA (Say) The snail Polygyra clausa is easily confused with small specimens of Polygyra thyro'ulus. However, clausa generally averages smaller than thyroidus, the shell of the former measur- ing about one-half to five-eighths zs=»-t,>_ of an inch (14-17 mm.) in diam- X^'^^^^^^^^^^^''''?^ eter. The shell of clausa, which is /""^^f"""^ j>^^v yellowish, is comparatively higher / iM ^' Aa .^.^ ^ ^^^^ than that of thyroidus. Further- R^^^^^^^^^^^^^% more, the umbilicus of clausa is ^^^^^ ^ m plj ^^^^^^a^ much smaller than that of thy- ^^^^^^L ^^^^^^P / ro'tdus ; sometimes it appears as ^^^^^ ^:^3^^^^ a mere slit behind the reflected peristome, which is comparatively narrow and somewhat round- ed, not widely expanded and flat as in thyroidus; clausa never has a parietal denticle. These details separate the tw^o species. The animal of Polygyra clausa is generally blackish in color. Polygyra clausa is widely distributed over Illinois, although usually not many individuals occur in a single colony. For the most part, it lives in river valleys, in forests of oak, elm and hickory. It has been collected from railway embankments and other parts of the rights-of-way where grass and small shrubs grow abundantly. Such places may be described as prairie habitats. Thomas Say described this species as Helix clausa in 1821, in the Journal of the Philadelphia Academy of Natural Sciences, in which were published descriptions of many of the land and freshwater species which he discovered. It is interesting to know that the first specimens came from Illinois, and that Say gave this state as the type locality. Polygyra clausa is found in many parts of the United States. Records are available indicating its presence from Minnesota southward to Kansas and Alabama and eastward to western Pennsylvania. Throughout this area it exhibits little variation and in this respect it appears to be one of the most distinct species of American land snails. In Alabama and other parts of the South it might be confused with the small form of thyroidus, known as bucculenta, but in that variation the shell is usually without an umbilical opening and the aperture is not rounded as in clausa. 58 POLYGYRIDAE POLYGYRA STENOTREMA (Ferussac) Shells of the species Polygyra stenotrema and the species Polygyra hirsuta may be distinguished from all others in Illinois by a little notch on the base of the peristome and by a long, curved plait located on the parie- ^^.^Z^^^^^^^^ tal wall. This fold in stenotrema is so large that it almost closes the aperture. The brownish shell of stenotrema is less than one-half inch (10 mm.) in diameter and much wider than high. It has 5 whorls. The upper end of the heavy, curved parietal plait fits into a baylike cavity in the outer lip or peristome. The lower part of the peristome is thickened and has a small notch near the middle. The surface of the shell is covered with small hairlike projections from the epidermis. The large white lamella which completely hides the aperture when the shell is viewed from the front is its chief distinguishing character. This is typically a southern species, which is abundantly distributed throughout Tennessee, Alabama and Georgia. The only lot from Illinois which has been examined by the author was collected by a survey party in an old quarry near Elizabeth- town, Hardin County, on the Ohio River. Polygyra stenotrema is abundant in the southern part of Indiana and is distributed up the Wabash Valley as far as Parke County. The Illinois specimens of Hardin County are evidently emigrants from Indiana. The species should be found in other places in Illinois along the Ohio and Wabash rivers, but diligent search during several seasons has failed to discover it in the localities examined. In the Classified Catalogue of American Land Shells by Pilsbry and Johnson, published in 1897, stenotrema is listed as from Henry County, Illinois. This record is republished in A Catalogue of the Mollusca of Illinois. Xo specimens of steno- trema have recently been collected from Henry County, and none occurs in the Nason or Hinkley collections in the Natural History Museum of the University of Illinois. Because Henry County is rather far north for stenotrema. the record for this county should be viewed with suspicion. POLYGYRIDAE 59 POLYGYRA HIRSUTA (Say) One of the smallest of this genus of snails, Polygyra hirsuta has a shell measuring but slightly more than one-fourth inch (7-9 mm.) in diameter. It differs from its relative, Polygyra stenotrema, in its smaller size, in its much smaller parietal plait, which does not seem to close the 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 Tittle 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. 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. — William Walsh am How, Good If'ives 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 THonodon 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 Lobosculujn 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 leporina 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 Lobosculinn was instituted in 1930 by Dr. Henry A. Pilsbry to contain certain small Polygyra-\\\it snails which differ from the true Polygyra in details of anatomy. The species previously known as Polygyra piistula (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. 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 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 Eiiconnlus 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 1. Shell 3^ inch or more in diameter 2 Shell 3^ inch or less in diameter 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 3. Shell about ^^ inch in diameter 4 Shell less than ]/% inch in diameter 6 4. Body whorl greatly enlarged toward aperture. . .Retinella, p. 69 Body whorl not enlarged toward aperture; whorls evenly coiled, p. 79 5 5. Shell 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 of whorls 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 . . Hawaiiay p. 72 \\\ 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 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 friabilis, p. 67 Aperture obliquely ovate; interior of aperture pearly cupreus, p. 66 66 ZONITIDAE MESOMPHIX CUPREUS (Rafinesque) The copper-colored shell of the snail Alesomphix cupreus attains a diameter of about an inch (24 mm.). In specimens from Illinois the height of the shell is approximately two-thirds of the diameter. The depressed although somewhat dome-shaped jfT/IH' ^ 7Wffir;'^i£>v 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 OmpJialina 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 Alesomphix 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. Alesom- 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 Mesoinphix 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 Mesornphix perlaevis vulgatus is likely to be confused with shells of Mesornphix cupreus and Mesornphix friabilis. It differs from them in the following particulars. The 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 ni 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. Mesornphix 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. The variety Mesornphix perlaevis vulgatus is common to abundant in the hill region of southern Illinois 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 laevigata 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 a very small perforation indentata, p. 71 Base of shell not flattened; distinct umbilical opening, p. 70. . 2 2. Umbilical opening elliptical wheatleyi, p. 70 Umbilical opening round, p. 70, fig. C 3 3. Shell with impressed radiating lines widely and regularly spaced rhoadsi^ p. 70 Shell with impressed radiating lines close together electrinay 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, f^g. A, page 70. Retinella electrina, also known as / itrca 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. RETINELLA WHEATLEYI (Bland) The yellowish, glassy shell of Ret- inella ivheatleyi, fig. B, less than one- fourth inch (5 mm.) in diameter, is wider than that of Retinella electrina in proportion to its height and has a more depressed spire, a flatter base and a wider umbilicus. The umbilicus is peculiarly expanded, causing it to be elliptical, in contrast to the round umbilicus in electrina. The species wheatleyi is found in much the same habitats as electrina ; rarely in woodlands bordering agricul- tural lands. In Illinois it appears to be confined to the southern half. RETINELLA RHOADSI (Pilsbry) The yellowish shell of Retinella rhoadsi, fig. C, less than one-fourth inch (4 mm.) in diameter, may be known from that of Retinella elec- trina, which it resembles, by the fact that its impressed, radiating lines, which are especially well developed on the upper surface, are widely and regularly spaced, resembling those of the shell of Retinella indentata. In Illinois, rhoadsi is known only from the south end of Fountain Bluff in Jackson County. ZONITIDAE 71 RETINELLA INDENTATA (Say) The small, yellowish, glassy shell of Retinella indentata measures about one-fourth inch (5 mm.) in diameter and is only about half as high as wide. The impressed radiating lines are equally spaced and widely sepa- rated. The base is flattened, and the umbilical region, which is markedly indented, has only a very small chink. or perforation. No other shell in Illi- nois has this peculiarly indented and almost imperforate base. The animal is blue-black, and has lighter shades of coloring on the mar- gin and posterior extremity. This snail, which was first observed by Thomas Say more than a hundred years ago, is one of the most abundant Illinois species. It may be found living in almost every county in the state. It is found in the river valleys, in wooded areas and in former prairie lands, associated with Retinella electrina, Zonitoides arboreiis and other small snails. Its most favorable habitat, like that of so many other small snails of the state, is in woodlands of oak, elm, maple and hickory. It may be found under loose bark, woodland debris and fallen limbs of trees. Retinella indentata is widely distributed throughout the United States and parts of Canada and Mexico. Its range as known at present is from Ontario, Canada, southwest to lower California and central Mexico, and from the Dakotas east- ward to the Atlantic states. Throughout this wide area it exhibits little variation. Only one race besides the typical is known in this area, and that is confined to the southern United States and Mexico. A closely allied species, Retinella cryptomphala, is common in Tennessee and Alabama but has not surely been detected in Illinois, since specimens reported as cryptomphala, collected at Albion, Edwards County, proved upon close examination to be a variation of the common indentata. This Illinois locality is far removed from the usual localities in which cryptomphala lives, and the record appears to be erroneous. 72 ZONITIDAE Genus HAWAII A Gude Only one species of the genus Hawaiia is found in Illinois. The small size, peculiar umbilicus and silky appearance of the shell distinguish this gejius. HAWAIIA MINUSCULA (Binney) A little snail, Hawaiia minuscula has a shell less than one- eighth inch (2.5 mm.) in diameter. Each of the 4 tightly coiled whorls is separated from the next by a distinct suture. The spire is depressed and the base flattened. The whitish, hyaline surface is marked by many closely set lines of growth that give the shell a silky appearance. A large, round umbilicus at the base shows all of the whorls clear to the apex. The small size and the peculiar umbilicus separate this shell from all others found in Illinois, except that of Helicodiscus singleyanus inermis, the surface of which is not silky, but smooth like paraffin, and the umbilicus of which, although resembling that of Hawaiia minuscula, is not so deep. Long known as Zonitoides minusculus, Hawaiia minuscula is abundantly though sporadically distributed throughout Illinois. It has doubtless been overlooked by many collectors on account of its small size. Its most common habitat is in woodlands of oak, hickory and sycamore. The name Hawaiia kawaiensis was first given to a small zonitoid snail living in the Island of Kauai of the Hawaiian group, by the English conchologist, G. K. Gude, in 1911. This snail previously had been named Helix kaicaiensis by the Ger- man conchologist, L. Pfeif^er, in 1854. Suspecting that the Hawaiian snail might be an American form, Dr. H. B. Baker dissected the animal and found its anatomy to agree essentially with that of Michigan specimens of Helix minuscula. It appears, therefore, that the Hawaiian snail kawaiensis was described from specimens of the American minuscula which had been introduced into the Island of Kauai. Thus, the generic name Hawaiia, first bestowed upon a snail in far off Hawaii, becomes the name of a common snail of Illinois. ZONITIDAE 73 Genus PARAVITREA Pilsbry In Illinois occur two species of the genus Paravitrea which might at first sight be taken for variations of one of the Retinella snails, especially elect rina, ivheatleyi or rhoadsi. Three distinct differences separate the Paravitrea snails from any of the Retinella group. The shells of Paravitrea have 6 whorls {Reti- nella, 4) ; the whorls are very tightly coiled (in Retinella, loosely coiled) ; and the small, round and deep umbilicus is placed exactly in the center of the base of the shell {Retinella has the umbilicus somewhat off center because the last whorl is expanded). The genus Paravitrea is a group new to Illinois collectors, neither of the two species represented appearing in A Catalogue of the Mollusca of Illinois. The genus includes 18 species and races, mostly southern in distribution. Central Illinois appears to be the northern extension for the genus except for one peculiar form, Paravitrea multidentata, named by William G. Binney, which extends its range as far north as the states of Maine and Michigan. Key to Species Aperture obliquely ovate signijicans, p. 74 Aperture horizontally ovate capsella, p. 73 PARAVITREA CAPSELLA (Gould) The pellucid amber shell of the snail Paravitrea capsella is less than one-fourth inch (5 mm.) in diameter. The height is one-half the diameter. The 6 whorls are very tightly coiled, the spire is flattened and the surface is marked with distinct, spaced, radiating and impressed lines. The aperture is regu- larly lunate, and the deep umbilicus is placed in the center of the round base. The animal is blackish in color. This zonitoid, formerly known as litrea capsella, in Illinois is confined largely to the southern half of the state, its northern- most record being Vermilion County. It may be found under loose bark, on the underside of fallen branches and, rarely, under leaves in woodlands of oak, hickory, elm and pine. As a rule only a few specimens of Paravitrea capsella are found in one locality. 74 ZONITIDAE One of the surprises of the 1932 molluscan survey of Illinois was the discovery of the supposedly southern species, Paravitrea capsella. This spe- cies had not been reported from Illi- nois previously, its nearest recorded localities being Fayette County, Ken- tucky, and Posey County, Indiana. It is now known from seven counties in Illinois, and the Natural History Mu- seum of the University of Illinois con- tains specimens from Jefferson and Parke counties, Indiana. That this species has been in Illinois for a long time is evidenced by its discovery in Pleistocene deposits of early Wisconsin age in Stony Creek, near Muncie, Vermilion County, Illinois. PARAVITREA SIGNIFICANS (Bland) The shell of Paravitrea significans is similar in size, color and general appearance to that of Paravitrea capsella. measuring less than one-fourth inch (5 mm.) in diameter. It may be distinguished from the capsella shell by its peculiarly flattened and concave base, and the position of the periphery of the body whorl, which is placed well below the middle of the whorl, causing the aperture to be strikingly diagonal to the vertical plane of the shell. In significans the spire is somewhat high- er than in capsella. In these two spe- cies half-grown shells are more diffi- cult to distinguish than are mature shells. Young shells of significans usu- ally have one or two pairs of small denticles which show through the shell as white spots, illustrated in the small figure. More common than capsella, but with similar habitats, sig- nificans also is confined, in Illinois, to the state's southern half. ZONITIDAE 75 Genus EUCONULUS Reinhardt The genus Eitconulus is distinguished by small, glassy, yel- lowish-white, beehive-shaped shells, none of which much exceeds one-eighth inch (3-4 mm.) in diameter. The height of the shell is usually over three-fourths the diameter. The base of the body whorl is convex. The upper surfaces of the whorls are well rounded, and the sutures are deeply indented. The umbili- cal opening is small. The edge of the outer lip is thin. The animal is bluish black on the head and upper part of the body, which shades to a lighter color on the sides and base. The foot is very narrow and elongated. The Euconulus snails, most abundant in floodplain areas bordering streams, live under loose bark and on decayed logs in forests of oak, elm, hickory and persimmon. Only rarely are more than two snails found in one spot. Key to Species Shell with 6 to 63^-2 whorls; body whorl rounded. . . .chersinuSy p. 76 Shell with 5 whorls; body whorl angular fulvus, p. 75 EUCONULUS FULVUS (MiJller) The small, yellowish-white shell of Euconulus fulvus meas- ures about one-eighth inch (3 mm.) in height and slightly more (4 mm.) in diameter. The whorls. 5 in number, are rounded on the spire, but slightly angulated at the periphery on the body whorl, the angle usually disappearing at the end of the first half turn of the whorl. The whorls are wider than those in Euconu- lus chersinus, and the aperture is elliptical. Occasionally speci- mens are found in which the carination of the body whorl is rather sharp and is continued to the aperture. The species is found widely scattered throughout Illinois. 76 ZONITIDAE EUCONULUS CHERSINUS (Say) The glassy, yellowish-white shell of Euconulus chersinus has at least one more whorl, 6-6V^, than that of Euconulus fulvus, and the whorls are more closely coiled. The body whorl of the mature shell is usually rounded and not angulate as in fulvus. However, all immature shells of the genus are distinctly angulate on the periphery. Euconulus chersinus, especially the typical form, is abundant in hilly regions bordering the large Illinois rivers. Occasionally it is found in isolated woodlands containing oak, cherry, hickory or ironwood. Of the two species, fulvus and chersinus, the latter is the more abundant and more generally distributed through- out Illinois. Euconulus chersinus chersinus (Say). The height of the typical chersinus shell, shown in the figures below, is as great as or greater than the diameter; each dimension is about one- eighth inch (2.8-3.0 mm.). The spire is higher than that of fulvus. Euconulus chersinus polygyratus (Pilsbry). Although the shell of this race is about the same size as that of the typical form and has the same number of whorls, the spire is less elevated, be- cause the whorls are narrower and more tightly coiled. In chersinus pol- ygyratus, the periphery is higher on the body whorl, causing the aperture to be narrower and higher than in cher- sinus chersinus. Known records indicate that cher- sinus polygyratus in Illinois is confined to the northern part. Cook and Henry counties being probably the southern limit. ZONITIDAE 77 Genus STRIATURA Morse Five species and races of Striatura are found in the United States. The one species and one race occurring in Illinois are characterized by their small size and by the surface sculpture of raised folds or ribs. STRIATURA MILIUM (Morse) One of the smallest species of land snails found in the state, Striatura jnilium has a greenish-white shell measuring less than one-sixteenth inch (1.5 mm.) in diameter. It may be recognized by its diminutive form, its widely open umbilicus and the sculpture of the 3 whorls, which consists of many raised folds or ribs that at times run together. In the upper surface of these folds, fine im- pressed lines cross the vertical ribs in such a manner as to form a reticulated surface sculpture. Striatura milium milium (Morse). In the typical variety, shown in the figure, the apical or nuclear whorls are smooth or only faintly lined. The spiral lines on the lower whorl are faintly developed. This variety lives in woodlands in old decaying wood. The only Illinois locality from which it has been recorded is in McHenry County. Striatura milium meridionalis (Pilsbry & Ferriss). The variety Striatura milium meridionalis, found in the southern part of Illinois, differs from the northern form in certain con- stant variations. It is a trifle larger. Strong, incised spiral lines mark the apical or nuclear whorl. The spiral lines are distinct in the base of the shell and are conspicuous in the widely open umbilicus. The oblique wrinkles or ribs are also much coarser in meridionalis than in the typical shell. This sculpture can be seen only with the aid of a good hand lens magnifying 12 to 15 diameters, or with a microscope. The form meridionalis, noted in Washington and Monroe counties, appears to be the dominant variety of milium in southern Illinois. It is probably an example of a migrant from the south, since meridionalis is common there. 78 ZONITIDAE Genus ZONITOIDES Lehmann The shells of Zonitoides, about the size of those of Retinella and Paravitrea, do not have the latter's tightly coiled whorls, nor the former's spaced, impressed lines on the body whorl which extend from the suture to the base. All species of Zoni- toides have depressed, shining shells, strikingly umbilicated. The lines of growth are visible to the human eye only when aided by a simple lens. Fine microscopic spiral lines are also present in some species, but a powerful magnifying glass is needed to find them. The figure shows the shell and animal of Zonitoides arboreus, which is one of the most common of the land snails found in the state of Illinois. Key to Species 1. Umbilicus wide and shallow; surface of shell sculptured. . . . Ii7jjatnlus, p. 80 Umbilicus deep and narrow, p. 79; surface of shell smooth and shining 2 2. Aperture round, p. 80; umbilical opening one-fifth diameter of shell; diameter of shell about ^4 inch (6.0-7.5 mm.) .... nJtiduSy p. 79 Aperture ovate, p. 79; umbilical opening one-sixth diameter of shell; diameter of shell less than l^'^^. ly fills the aperture. The waxy white shell has 5 rounded whorls with deep sutures, and a conspicuous rounded ridge behind the peristome. The aperture, somewhat triangular in form, has 2 palatal folds, the upper one small and the lower one large; both are rounded and rather deeply set in the aperture. It has a large, rounded and deep-seated columellar lamella, in front of which is a large vertical callus on the inner lip. Fairly common over Illinois, and in some localities abundant, Gastrocopta con- tracta lives under a variety of conditions: on river and creek floodplains where there is plenty of moisture, in forests of syca- more, oak and elm; on hillsides in forests of oak, elm, hickory, basswood and pine ; on bluffs of limestone; and even on dry railway embankments, although it is scarce in the last habitat. It is common in isolated woodlands of oak, elm and hickory. Two races of this species have been distinguished in Illinois. f 98 PUPILLIDAE Gastrocopta contracta contracta (Say). Figs. A and B. The shell of the typical Gastrocopta contracta is wide and conic, and the upper lamella, which in this species is a combination of the parietal and angular lamellae, is shaped somewhat like the letter L with a tail. This can be seen only by breaking away the outer lip so that the whole of the lamella is exposed. The large, rounded columellar lamella and lower palatal fold are situated far within the aperture. Gastrocopta contracta climeana Vanatta. Figs. C and D. The race of Gastrocopta contracta known as climeana is sepa- rated from the typical form by a difference in the upper com- posite, L-shaped lamella. In climeana the L lacks the appendage or tail which is present in contracta contracta. The lip must be broken away to make this lamella clearly visible. Only one Illinois locality is known for this race, Dubois, Washington County. Gastro- copta contracta climeana has been considered southern in distribution, its previously record- ed northern limit being Arkansas and Missis- sippi. In a record of the Mollusca found in the vicinity of Dubois, A. A. Hinkley {Nautilus, Volume 33, page 14, 1919) lists a variety, Gastrocopta contracta ahrupta, stating that Dr. Victor Sterki had proposed the name. This appears to be a nude name, Hinkley's use of the name being the only one known. The original shells from Dubois are in the Museum of Natural History of the Uni- versity of Illinois (no. Z25091). They do not differ materially from the varieties contracta or climeana and appear to be the same as other material from Dubois. All of the specimens in the Hinkley collection labeled abrupta upon examination proved to be of the variety climeana, having the characteristic L shape of the parietal lamella. It appears that the name abrupta is a synonym of climeana', the latter variety was first diagnosed in 1911, whereas abrupta was first listed in 1919. It would be of great interest to ascertain whether the climeana variety might not be found in southern Indiana or Ohio. PUPILLIDAE 99 Few conchologists take the trouble to cut open the shells of small species, which is the only method by which these two forms of contracta described here can be distinguished. GASTROCOPTA HOLZINGERI (Sterki) The snail familiarly known as Holzinger's Gastrocopta has a white glassy shell which is little more than one-sixteenth inch (1.7 mm.) in height. Cylindric in shape, the shell has 5 rounded whorls, regularly decreasing in size as they approach the apex, fig. A. The shape of the aperture is round, not triangular as that in Gastrocopta contracta. The lamellae and folds of holzingeri differ very markedly from those of contracta. The parietal lamella, which is forked in front, somewhat resembles the letter Y, fig. B. The basal fold is large, and the lower palatal fold is pyramidal rather than rounded in shape. The columellar lamella is larger and more conspicuous in holzingeri than the same lamella in contracta. Gastrocopta holzingeri apparently is a rare species in Illinois. Records of it are at present known from only four counties in the state: Will and La Salle in the northern part, Hancock in the cen- tral area and Jackson in the southern zone. The habitat of this snail, similar to that of Gastrocopta contracta, is on wooded floodplains w^here moisture is abundant; in forests and woodlands of sycamore, elm, oak, basswood and hickory; and on limestone bluffs. The young conchologist often wonders about the person whose name follows a specific designation. Dr. Victor Sterki, who is the author of Gastrocopta holzingeri, was a practicing physician living in New Philadelphia, Ohio. Unlike the many naturalists who prefer to study the large species, Dr. Sterki was drawn to the study of the minute forms of mollusks. The tiny pupoids first attracted his attention, and he made a careful study of the American species, finding several which had been overlooked by other conchologists. 100 PUPILLIDAE GASTROCOPTA PENTODON (Say) Shells of the species pentodon and tappaniana are distin- guished from other species of the genus Gastrocopta found in Illinois in size and form. The shells measure about one-sixteenth " inch (1.5-2.0 mm.) in height and are of an opaque white color, like par- affin or spermaceti. They have a simple parietal lamella and palatal folds that are arranged on a white, rimlike callus. The shell of Gastrocopta pento- don has 5 rounded whorls separated by distinct sutures. In shape it is usually ovoid, sometimes c>'lindroid. The palatal folds vary in num- ber from 2 to 5, the additional folds being intermediate in size between the primary upper and lower palatal folds. The shell has a large rounded columellar lamella and a small basal fold. It has a rather distinct crest or swelling behind the outer lip, resembling that found in contracta. The parietal lamella and the lower palatal fold are slightly curved. This species is distributed throughout Illinois, but the records are widely scattered. It is found in a variety of habitats; on wooded hillsides in forests of oak, cherry, iron- wood and basswood, under leaves and debris and also in grass in open places. It is seldom found in wet places. Gastrocopta pentodon pentodon (Say). Figs. A and B. The typical Gastrocopta pen- todon is only about one-sixteenth inch (1.50- 1.75 mm.) in height. It has usually 5 palatal folds. Variations in individual shells of the typical variety are illustrated in figs. A and B. Gastrocopta pentodon gracilis (Sterki). Fig. C, The shell of pentodon gracilis is more elongated than that of the typical pentodon, and more nearly cylindrical. It has usually only 5 folds and lamellae. On the outer lip, only the upper and lower palatal folds are present. This variety, rare in Illinois, is at present known only from Jackson, Union and Lawrence counties. PUPILLIDAE 101 GASTROCOPTA TAPPANIANA (C. B. Adams) Larger and more sharply conic than that of Gastrocopta pentodon, the opaque white shell of Gastrocopta tappaniana measures over one-sixteenth inch (2 mm.) in height. The spire has an obtuse apex, the parietal lamella is straight and the lower palatal fold is usually not so long as is that in pentodon. There are usually 6 (sometimes as few as 2) folds on the outer lip. The figures show variations in individual shells. Gastrocopta tappaniana is found beneath pieces of wood, logs and damp debris in wet places such as floodplains, moist woodlands and swamp edges, while Gastro- copta pentodon prefers drier situations. It is distributed through- out Illinois in about the same scattered manner as Gastrocopta pentodon. GASTROCOPTA CORTICARIA (Say) Measuring less than one-eighth inch (2.5 mm.) in height, the shell of Gastrocopta corticaria usually has but 2 lamellae, a parietal lamella and a columellar lamella. Occasionally it has another lamella, the angular, developed and united with the parietal lamella. In rare indi- viduals the aperture is without lamellae. The shell has no folds on the outer lip, and no fold at the base of the aperture. Gastrocopta corticaria is unique among the species of this genus in having the folds and lamellae very few in number. No other Gastro- copta is comparable to it. This tree-inhabiting Gastrocopta is distrib- uted throughout Illinois in a scattered manner. Its habitat is on hillsides, river bluffs and wood- lands where oak, elm, basswood and hickory are the usual forest trees. The species corticaria, the "bark in- habiter," is often observed as high as 2 feet from the ground on the trunk of a tree. 102 PUPILLIDAE GASTROCOPTA PROCERA (Gould Pupoids of the species procera, which is mostly southern in distribution, are rare in Illinois. The shells of this species are usually cinnamon-brown in color, somewhat glossy in texture and marked by lightly impressed lines of growth. They have 5 or 6 convex whorls with sutures that are noticeably deep. Gastrocopta procera procera (Gould). Pig. A. In the shell of the typical variety, less than one-eighth inch (2.5 mm.) in height, the body whorl has a perceptible crest behind the outer lip. The rounded aperture has 5 folds and lamellae: a bifid parietal lamella representing the combined parietal and angular lamellae, a columellar la- mella, a small upper palatal fold, a large loAver palatal fold placed far within the aperture and directly under the parietal lamella, a small basal fold placed well within the aperture. The ^nde peristome is rolled outward. This variety is abundant in Illinois only near Albion, Edwards County, but it is reported from eight other counties, of which Du Page is the most northern and Union the most southern. Its habitat is under leaves and about old logs and sticks. Gastrocopta procera mcclungi (Hanna & Johnson). Fig. B. This variety, less than one- eighth inch (2.2 mm.) in height, is somewhat smaller than the typical form. The thickened peristome of jncclutigi is more convex, so that the greatest thickness of the lip callus is at the edge of the aperture, and not within the aperture as in procera procera. The parietal lamella is bifid and forked in front, and the col- umellar lamella has a nodule at the base which gives it the appearance of being duplicated. Only a very few specimens of this rare variety have been collected in Illinois. It has been found on a railway embank- ment in Effingham County, on a Mississippi River bluff in Monroe County and on the isolated hill bordering the Missis- sippi River at Grand Tower in Jackson County. PUPILLIDAE 103 Genus VERTIGO Draparnaud The small pupoids of the genus Vertigo differ from most snails of the genus Gastrocopta in having brown shells. Of the Illinois Gastrocopta snails only Gastrocopta procera has a brown or cinnamon-colored shell. The outer lip of the usual J ertigo shell has an indentation in the middle, the shell is usually more globose in form than that of the gastrocoptas and the parietal and angular lamellae are more often separated to form distinct denticles. The animal lacks the tentacles of other pupoids. The eye peduncles are long and pointed. The body of the animal is short, blunt before and tapering behind. Several species of Vertigo are found in Illinois. Special search should be carried on by Illinois conchologists for members of this genus, of which species other than those listed in this handbook may be found living in the state. Vertigo gouldii Binney has been reported by Hinkley from Rockford, Winne- bago County, and by Marsh from Will County, but these reports have not been verified. No specimens have recently been seen from Illinois which could be referred to this species. How- ever, it has been authentically reported by Daniels from Indiana and may possibly be found in the northern part of Illinois. Key to Species 1. Palatal folds very long and extending tar back into aperture fniliuniy p. 107 Palatal folds tubercular and placed near edge of peristome, p. 104 2 2. Aperture with 2 denticles on parietal wall and 2 columellar denticles, p. 104 3 Aperture with only 1 denticle on parietal wall and 1 col- umellar denticle, p. 106 4 3. Shell cylindroid; whorls 6^2 morseiy p. 104 Shell ovoid or ventricose; whorls 5 ovata, p. 105 4. Aperture with but 1 palatal denticle and with no basal denticle tridentata^ p. 106 Aperture with 2 palatal denticles and a conspicuous basal denticle, p. 105 at bottom 5 5. Shell cylindroid; whorls 5; palatal denticles on a callus bor- dering aperture elatior, p. 106 Shell ventricose or ovoid; whorls 4; palatal folds or denticles not on a callus ventricosa^ p. 105 104 PUPILLIDAE VERTIGO MORSEI Sterki The largest species of the genus Jertigo found in Illinois is morsei, the dark brown shell of which measures nearly one- eighth inch (2.5-3.0 nim.) in height. This shell is cylindroid in shape and has 6^/^ well rounded whorls with deep sutures. The whorls increase regularly in height from apex to base. The aperture is rounded, and the middle of the outer lip is deeply indented. Vertigo morsei usually has 7 or 8 folds and lamellae in the aperture: a large parietal la- mella, a smaller angular lamella and a large columellar lamella with a smaller lamella be- low it, a very small basal fold, and an upper and lower palatal fold with sometimes a third fold above the upper fold. The size of the shell and the 2 or 3 lamellae on the parietal wall easily dis- tinguish this species from others of the genus. This species is known in the recent fauna of Illinois only from near Joliet, Will County. As a Pleistocene fossil it has been found in a number of places. Geologically it is one of the oldest living species in Illinois. The geographical distribution of Jertigo jiiorsei is very peculiar. It has been found only in New Jersey, Michigan, Ohio, Indiana and Illinois. In Ohio it has been reported from two localities, one a marl deposit. In Indiana, where it appears to be abundant in the living fauna, there are records from three counties. Its habitat appears to be most often near the shores of lakes. The name given this species is in honor of Dr. Edward S. Morse, one of the early students of land shells, who began his career in Maine. Dr. IMorse was an excellent artist and made all of the figures for his conchological papers. It is noteworthy that he was also the artist for Dr. William G. Binney's works on American land and freshwater mollusks. .'\n inadvertent step may crunch the snail That crawls at evening in the public path, But he that has humanity, forewarned, Will turn aside and let the reptile live. — William Cowper, The Task PUPILLIDAE 105 VERTIGO OVATA Say Although the shell of Vertigo tnorsei resembles that of /Vr- tigo ovata in the form and position of the folds and lamellae of the aperture, the two may be distinguished by a difference in size and in the number and shape of the spire whorls. The shell of ovata measures somewhat more than one-sixteenth inch (2 mm.) in height. It has 5 whorls, which are proportionately wider than those in morsel and increase in height more rapidly from apex to base. The ventricose form of the last or body whorl is also different. Vertigo ovata is somewhat amber colored. The habitat of the snail Vertigo ovata is in moist places under sticks and debris. It is most abundant on stream floodplains, but it has been found also in forests on the bluffs that border rivers. This species, scatteringly distributed over Illinois, has been reported from Fulton, McHenry, Cook, Menard, Winnebago, Washington. Edwards, Jackson and White counties. However, it is common only from the vicinity of Rockford, in Winnebago County, and of Albion, in Edwards County. Winnebago County is its most northern Illinois locality, Jackson its most southern. VERTIGO VENTRICOSA (Say) The shell of Vertigo ventricosa differs from that of Vertigo ovata in size and shape. It is a trifle smaller, measuring about one-sixteenth inch (1.75 mm.) in height. The glossy, light brown or auburn-colored shell of 4 whorls is often translucent. It has a lamella on the columella, a basal fold and an upper and a lower palatal fold. It has one parietal la- mella. These characteristics distinguish it from the shell of ovata. At present only one Illinois locality is known where ventricosa may be found. Specimens are known from near Rockford, Winnebago County, but even in that locality this species is rare. 06 PUPILLIDAE VERTIGO ELATIOR Sterki The elatior species of Vertigo is larger than Vertigo ventri- cosa. The brown shell of elatior, measuring over one-sixteenth incli (2.25 mm.) in height, has 5 whorls, one more than is present in ventricosa. It is more elongated and more nearly cylindrical. The folds and lamellae in the aperture are the same in number, 5, as in ventricosa. but the basal fold is larger, and the palatal folds are placed on and merge into a strong callus or thickening within the outer lip. Curiously, in Illinois Vertigo elatior is known only from Rockford, Winnebago County, where Vertigo ovata is found. It is rare in the living fauna, but as a Pleisto- cene fossil, under the name of Vertigo loes- sensis F. C. Baker, It is very abundant and widely distributed in Illinois and other parts of the Middle West. VERTIGO TRIDENTATA V^olf The small amber-colored shell of Vertigo tridentata is little more than one-sixteenth inch (2 mm.) in height. It has 5 smooth whorls. The small number of folds and lamellae distinguishes this species from the other vertigos of Illinois. The two figures illus- trate some of the individual varia- tions within the species. The habitat of Vertigo triden- tata is in grass or weeds. It has been observed clinging to stalks of weeds as high as 3 feet from the ground. Vertigo tridentata has been col- lected in Will, La Salle, Champaign and Fulton counties. Its first known habitat was In Fulton County, where it was dis- covered by an Illinoislan, John Wolf, about 1870. The vertical line beside the smaller figure Indicates the height of the specimen represented. The shell represented by the figure at the right is proportionately larger. I PUPILLIDAE 107 VERTIGO MILIUM (Gould Smallest of Illinois vertigos, milium has a shell that meas- ures about one-sixteenth inch (1.50-1.75 mm.) in height. In color the shell is dark amber or chestnut. It has 4 to 5 rounded whorls, and its general shape is globose. The aperture has 6 folds and lamellae: a parietal, an angular and a columellar la- mella, a basal fold, and an upper and a lower palatal fold. The palatal folds differ from those of other species found in Illinois. They are very long and extend far backward into the aperture. The small size of the shell, the shape of the palatal folds and the down- ward ending of the columellar lamella dis- tinguish the species Jertigo milium from all other pupoids. This minute pupoid is well distributed over Illinois, but the records are scattered. Its small size has doubtless caused it to be overlooked. Its habitat is under sticks and debris in moist floodplain areas and in woods on bluffs bordering the large rivers of the state. J'ertigo milium is so peculiar in its apertural folds and lamellae that Dr. Victor Sterki placed it in a subgenus which he christened Angustula. In this group the columellar lamella is crescentic in shape and its inner end curves downward, instead of upward, as in other species of J'ertigo. Only two species are known to belong to this subgenus: milium, the distribution of which is from Maine to Florida, west to South Dakota and Colo- rado and south to Arizona, Tampico, Mexico, and Jamaica; and bermudetisis Pilsbry, which is found only on the Island of Bermuda. It is noteworthy that a species having such a wide geographi- cal distribution should not show some varietal changes some- where in its range, but this species is remarkably uniform in its general characteristics wherever found. The consistency of milium over a large area leads to a consideration of one of the mysteries of animal life. Why one species should be uniform over a wide territory and another develop a number of races or varieties, as is the case in several species of Gastrocopta, is at present concealed from human knowledge. 108 PUPILLIDAE Genus PUPOIDES Pfeiffer Most species of the family Pupillidae found in Illinois have folds or lamellae in the shell aperture. However, two species, one of which "belongs to the genus Pupoides and the other to the genus Columella, lack these formations. In the two other Illinois genera of this family, Gastrocopta and Vertigo, the folds and lamellae which are present serve as valuable distinguishing characteristics. A distinguishing mark of the genus Pupoides is the reflected lip or peristome of the shell, which forms a thick, wide margin to the aperture. PUPOIDES MARGINATUS (Say) The shell of the species know^n as Pupoides ?narginatus has a rounded aperture with a peristome that is broadly reflected. The aperture is entirely without lamellae or folds. The brown shell of this species is about one-fourth inch (5.5 mm.) in height. It has 6 whorls and a very small umbilical perforation. The shell of Pupoides marginatus is elongated and tapers regularly to a point. No other land snail of Illinois resembles this species, which is the only species of its genus found in the state. The animal of the species marginatus has long and slender eye peduncles and very short tentacles. The color of the neck, head and eye peduncles is black; the posterior portion of the animal is lighter. Pupoides marginatus is widely distributed over Illinois. It has been recorded from numerous counties. It is particularly abundant in the counties of McHenry, Madi- son, Randolph, Jackson, Adams and Calhoun. Its most common habitat is on wooded bluffs and hillsides of rivers and streams, where oak, elm, basswood, hickory and sometimes pine are present. Occasionally this species is found in grass and on rail- way embankments. Every day I used to ride out alone along the seashore, where I dismounted, and filled my pockets with all sorts of pebbles, snail shells, and sea shells of great rarity and beauty. — Benvenuto Cellini, Autobiography PUPILLIDAE 109 Genus COLUMELLA Westerlund As in the genus Pupoides, the aperture of the shell in Columella is devoid of folds or lamellae. The shape of the Columella shell suggests an immature Gastrocopta. The lip or peristome in Columella is never reflected, as in Pupoides, but always thin and sharp. Only one species of this genus is recorded from Illinois. COLUMELLA EDENTULA (Draparnaud) One of the two species of Illinois Pupillidae without folds or lamellae within the aperture, Columella edentula has a brown shell one-sixteenth inch (1.5-2.5 mm.) in length. The 5 to 6 whorls are rounded, the aperture is almost circular, the peristome is sharp and thin and the parietal wall is turned over in such a way as partly to conceal the small umbilicus. This shell differs from that of Pupoides marginatus in its smaller size, blunter spire whorls, more nearly cylindrical shape and sharply edged outer lip. Apparently Columella edentula, a north- ern species, is not common in Illinois. It has been recorded from only three counties, McHenry, Fulton and Washington, in the northern, central and southern parts of the state. The Illinois habitats are under leaves in damp woods of floodplain areas. Unlike most of the other small snails of Illinois, this species does not occur in colonies; usually only a single specimen is found in a place. Columella edentula has been known under several names. It is listed in other manuals as Pupa simplex, Pupa edentula, Vertigo simplex and Sphyradium edentulum. Although the species Columella edentula is now rare in Illinois, a related species. Columella alticola (Ingersoll), was widely distributed throughout Illinois during the Pleistocene geological period. Columella alticola is abundant in fossil deposits known as loess, and its distribution extended as far east as central Illinois. It is found living at the present time in the higher regions of Colorado and other western states. no STROBILOPSIDAE Family STROBILOPSIDAE The family Strobilopsidae is a group of small snails having dome-shaped shells sculptured with oblique ribs. The shells have 4V2 to 6 slowly enlarging whorls and a distinctly open umbilicus. The aperture is provided with 2 or 3 parietal lamellae and sev- eral long, narrow basal folds which are deeply seated. This family is unlike all others in the possession of peculiar basal folds, which form a means of differentia- tion between species. Each fold has a definite position and name as indicated in the figure of the aperture at the bottom of this page. The animal of the Strobilopsidae is very small for the size of the shell. The head end of the body is black, the posterior end is grayish and the foot white. The tentacles are thick, bulb- ous and rather short, and the eye pe- duncles are short and thick, as is evi- dent in the figure on this page of Strobilops labyrinthica, show- ing a dorsal view of an animal of the Strobilopsidae. The Strobilopsidae may be found on decaying wood, under Parietal Lamella Interparietal Lamella infraparietal lamella Columellar' Lameluv Palatal Fold Basal Folds loose bark and in similar situations. In North America, species of this family have not been reported west of Nebraska and Kansas, but east of this area thev are abundant. STROBILOPSIDAE 111 Genus STROBILOPS Pilsbry The only genus of the family Strobilopsidae found in Illinois is Strobilops. In early works on land snails, this genus is found under the name Strobila. The change in nomenclature was made because the name Strobila had already been used. Most species of the genus Strobilops are found in Illinois. Key to Species 1. Parietal lamella broadened and slightly reflected near emerg- ing end aenea, p. 1 14 Parietal lamella not broadened and not reflected near emerg- ing end, pp. Ill, 113 2 2. Parietal and infraparietal lamellae emerging from aperture. labyrinthica, p. Ill Only parietal lamella emerging from aperture. . . .affinis, p. 113 STROBILOPS LABYRINTHICA (Say) The commonest Strobilops in Illinois, and the first one to be discovered and named by an American scientist, is labyrinthica. The shell is less than one-eighth inch (2.30 mm.) in diameter and about one-sixteenth inch (1.75 mm.) in height. The umbili- cus is small. Strobilops labyrinthica labyrinthica (Say). In the typical form, two of the lamellae, the parietal and the infraparietal, are visible from the front or base of the aperture, but the third, or interparietal, lying between these two, cannot be seen until the shell is broken open. The parts of these lamellae that emerge from the aperture are smooth, but within the chestnut- brown shell they are sawlike on the edge. The lamellae extend only half a turn within the whorl. Four of the 5 or 6 basal folds show through the base of the shell. These form a curving series toward the aperture. 112 STROBILOPSIDAE This Strobilops snail is found generally distributed over Illinois. Its habitat is in river valleys, on large river bluffs, in woodland areas and less often in second growth woods and on cut-over lands. Oak, elm, hickory, basswood, walnut and in places pine are its natural cover. It has been found in all of the state parks of Illinois, most often in second growth of oak and hickory, and in the White Pines Forest State Park, Ogle County, it has been found among pines. It is not common in floodplain areas of Illinois. Strobilops labyrinthica virgo Pilsbry. A color form or albino race of Strobilops labyrinthica^ virgo differs from the typical in having a whitish or slightly greenish shell with white lip and lamellae. In virgo the parietal lamellae emerge a little farther than in the brown typical form, and the umbilicus is. often a trifle smaller. The arrangement of the lamellae and folds is about the same in both forms. The shell is usually somewhat larger than that of labyrinthica labyrinthica and is more striking in appearance. In Illinois, it has been seen from only four counties: McHenry, Washington, Williamson and Saline. In McHenry County it occurs with the brown typical form. It was first discovered near Sebec, Maine. Its distribution extends from Maine to Minnesota. Strobilops labyrinthica parietalis Pilsbry. In this variety or form, the parietal lamellae penetrate more deeply into the shell aperture than in the typical variety, reaching as far back as two-thirds or, three-quarters of the last or body^l whorl. In other respects, this brown shell is similar to that of labyrinthica labyrinthica. In Illinois this variety has been found in three counties only: Wash- ington and Marion in the southern part of the state, and La Salle in the | northern part, where it is very rare. The recently described variety parietalis may be found to be more abundant in Illinois than the records indicate. Its distribu- tion is said by Dr. Henry A. Pilsbry to be sporadic, the known records being well scattered over the southeastern and southern parts of the United States. Careful preparation of the shell is needed for the determination of the variations of Strobilops. STROBILOPSIDAE 1 13 STROBILOPS AFFINIS Pilsbry The shell of Strobilops affinis differs from that of Strobilops labyrinthica in being larger. The glossy brown shell of affinis measures nearly one-eighth inch (2.50-2.75 mm.) in diameter. Shells of the two species differ also in that affinis has a wider umbilicus and coarser ribs on the surface. In affinis only the large parietal lamella emerges from the shell, whereas in labyrinthica two lamellae are visible at the aperture. The shell of affinis is more nearly conical in form than that of labyrinthica. The basal folds of affinis are 8 in number, 5 of which are distinctly visible through the translucent base of the shell. These basal folds are much shorter than are those in laby- rinthica and form a radial series to- ward the aperture. The parietal la- mellae penetrate more deeply than do those of labyrinthica labyrinthica but not so far as in the form that is known as labyrinthica parietalis. This comparatively large Strobilops is known only from northeastern Illinois in the counties of Lake, McHenry, Kane and Cook. It is a forest snail found in moist woodlands under loose bark and on old decaying wood. A few" years ago little was known concerning the species of the genus Strobilops, but thanks to the work of Dr. H. A. Pilsbry, Curator of MoUusca in the Academy of Natural Sciences of Philadelphia, the group has been carefully studied and a number of new species and races have been discovered. Of the nine species and varieties found in the United States and Canada, seven are known from Illinois. Recognition of specific variations has come about as a result of the method Dr. Pilsbry used of opening the shell for the examination of the lamellae and folds. The family Strobilopsidae has been well discussed and the species beautifully illustrated in Volume 28 of the Manual of Conchology, published by the Academy of Natural Sciences of Philadelphia in 1927. 1 14 STROBILOPSIDAE STROBILOPS AENEA Pilsbry A recently recognized species of Strobilops, aenea may be known by its depressed spire and bluntly angular periphery. The base of the shell is more flattened than that in any other species of this genus. Strobilops aenea aenea Pilsbry. The shell of the typical variety, which measures about one-eighth inch (2.00-2.75 mm.) in diameter, is dark brown with a peculiar golden gleam, unlike the coloration of any other shell of the genus. The typical Strobilops aenea has 2 emerging parietal lamellae, the infraparietal being very thin and extending but a short distance beyond the edge of the peristome. Internally, the parietal lamella is large and heavy, but the other lamellae are thin, and the interparietal lamella is very short. The lamellae are nodose or sawlike only far within the aperture. The 4 basal folds may be seen through the translucent base of the shell. They are peculiar in the fact that they alternate in size. The umbilicus is comparatively large. Like the typical Strobilops labyrinthica, the typical Strobilops aenea is distributed widely in Illinois. The northernmost county from which specimens of aenea aenea have been seen is La Salle, and from this locality southward it is the most common Strobi- lops. It has erroneously been recorded as labyrinthica, from which it is markedly distinct. The usual habitat of Strobilops aenea aenea is in the higher uplands, in forests of oak, elm, hickory, dogwood, walnut, sassa- fras and ironwood. Only rarely is it found in a floodplain valley and then only when the situation is dry. It is often abundant under loose or started bark, on the underside of old wood and on chips from forest cuttings. It occurs in old woods and in recent cut-overs wherever logs and decaying wood have accumulated. STROBILOPSIDAE 115 ^^^^OT^l^,^^^ Strobilops aenea micromphala Pilsbry. The micromphala variety of Strobilops aenea is dis- tinguished by a narrower umbilicus than is found in many forms of the genus Strobilops. Only the parietal lamella emerges from the aperture, and but 2 or 3 basal folds may be seen through the translucent base of the shell. The form of micromphala is more convex than that of the typical aenea, and the color is cin- namon-brown without the golden tint of the typical species. The shell of jnicrompliala is less than one-eighth inch (2.0- 2.5 mm.) in diameter. The variety micromphala is common to the lower Mississippi Valley and to the southwest in Arkansas and Louisiana. The present Illinois records, from White, Washington and Hardin counties, are the most northern known. The habitat of this form is in woodland areas similar to some of those inhabited by Strobilops aenea aenea. Strobilops aenea spiralis Pilsbry. A very rare Strobilops, 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 spiralis is distinct in its shape and in the position of the parietal lamella. It is known in Illi- 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. 1 16 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 l^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 ZV2 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 Sfrobihps: 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 J^allonia 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 wxll 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, pp. 116, 119 2 Shell almost smooth, showing onlv fine growth lines, p. 118 ■ 3 2. Umbilicus comparatively small; spire slightly elevated. . . . costata^ p. 1 19 Umbilicus wide; spire not elevated parvula^ p. 119 3. Shell straw colored; umbilicus ovate because of a rapid ex- pansion near latter halt of body whorl excentricay p. 118 Shell clear-glass colored; umbilicus round pulchella^ p. 118 (NO 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 ot softest down; A noble instinct; in all kinds the same, All ranks! — William Wordsworth, Liberty 118 VALLONIIDAE VALLONIA PULCHELLA (Muller: 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- ory, walnut and beech ; and railroad embankments, among grass and bushes. 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. VALLONIA EXCENTRICA Sterki Slightly smaller than Vallonia pulchella, the shell of J'al- 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 only from Champaign County, on the south side of the University of Illinois I^P:. campus and in the yard of Dr. H. J. \%, -;,' Van Cleave, Urbana. It is known x?/l?' '^ from Europe and parts of America. VALLONIIDAE 1 19 VALLONIA COST ATA (Muller) 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 measures over one-sixteenth inch (2.5 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, J'allonia parvula has an umbilicus proportionately larger than that of / allonia 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 J allonia 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 ^^^=i - / ^==i;^ % 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 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- fifths length of shell avara^ p. 124 Aperture ovate, occupying three-fourths to four-fifths length of shell, p. 122 ■ 2 2. Shell ovoid, somewhat inflated; aperture ovate; spire broad, p. 122 3 Shell much elongated, narrow; aperture narrowly ovate; spire acute, p. 125 4 3. Aperture regularly ovate; color greenish or yellowish ova/is, p. 122 Aperture obliquely ovate, expanded at lower part; color amber concordialiSy p. 123 4. Aperture occupying three-fourths length of shell, little ex- panded at lower part retnsa, p. 125 Aperture occupying four-fitths length ot shell, notably ex- panded at lower part salleana^ p. 127 122 SUCCINEIDAE SUCCINEA OVALIS Say Largest of the Succineidae found in Illinois is Succinea oralis. 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 ovalis 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 dififerent from the greenish shade of ovalis 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 SUCCINEIDAE 123 almost throughout the state. It is apparently more abundant In the northern than in the southern part of Illinois. The hatjitat 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. 24 SUCCINEIDAE SUCCINEA AVARA Say Two varieties of Succinea avara are found in Illinois: the typical avara and the smaller form called avara vuardiana. 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 flioodplain 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, rctusa 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 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, w^hose name is given as the author of this Succinea, 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 27 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 reiusa, 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. 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 it nobody should know but yourself, and I should imagine six or eight boiled in a quart ot water and strained off and put into a bottle, would be a good way, adding a spoonful or two ot that to every liquid she takes. They must be tresh done every two or three days, otherwise they grow too thick. — Marv (Granville) Pendares Delanev, .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 Limacldae, 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 Illinois are small and inconspicuous, but in the states bordering the Pacific Ocean occur several species belonging to the family Arlonldae 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 Limacldae, the long and narrow body Is somewhat humped toward the middle and front end, w^here 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 tall or posterior part of the animal tapers to a point: the upper side of the tall is carlnated near the end. At the edge of the mantle, near the posterior end, animals of the family Limacldae have a small opening, which Is the breathing pore or orifice. The small Limacldae are vegetable feeders, eating decaying vegetation, as well as healthy plants. Genus DEROCERAS Rafinesque The genus Deroceras Includes small Limacldae 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 AgrioUmax, 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 surtace of body covered with flattened tubercles; breath- ing pore with a white border agreste, p. 130 Upper surface of body covered with prominent tubercles; breath- ing pore not 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 ^rac He, 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 L'ljnax rnaximiis 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 131 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 . Phi/omycus, p. 131 Less than 1 inch long; mantle covering all but anterior one- sixth of body Pal/i/era, 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 carolinianiis 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 132 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 dor salts 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 dorsalis, p. 132 Body with dark spots on a whitish or flesh-colored ground Josteri^ 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, how^ever, 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 vet 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 MoUusca 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 neck. It may be recognized by the blackish spots on a whitish or flesh-colored mantle. These sp<3ts 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 aj)undant 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 Illinois, 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. Prison and Dr. H. H. Ross. The frugal snail, with fore-cast ot repose, Carries his house with him, where'er he goes; Peeps out — and if there comes a shower ot 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. — Charles Lamb, 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 MiJller In the genus Carychium, which contains the only species of the family Ellobiidae present in Illinois, 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 exiguum, p. 136 Surface of shell with vertical striations, as well as growth lines. . exile, p. 136 136 ELLOBIIDAE CARYCHIUM EXIGUUM (Say! In the species Carychiurti 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 AVz 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. C. Lea 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 widelv distributed over most of Illinois. Land Snails Introduced From Foreign Countries LAND SNAILS 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 Opens mauritianum. Of introduced slugs Limax maximus, Liniax fiavus 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, Avion circiimscriptiis 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 w^as 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 1139] 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. OXYCHILUS LUCIDUM (Draparnaud) The introduced species Oxychilus lucidum is larger than Oxychilus cellariu?n and the spire is more nearly flat. The shell of most lucidum 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 w^ider 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 141 LIMAX MAXIMUS Linnaeus The slug Limax rnax'unus was introduced from European countries. It is easily known by its large size, 6 inches (15 cm.) when fullv extended. 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 Xeoga, 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. LI MAX FLAVUS Linnaeus The large European slug Lunax flavus measures 3 to 4 inches (8-10 cm.) in length. It is smaller than Liniax maximus and differs from it in being somewhat narrower and more 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. TESTACELLA EUROPAEA de Roissy The peculiar sluglike mollusk Tesiacella curopaca 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 43 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 halioto'ules Lamarck. Land Snails Of Uncertain Presence in Illinois LAND SNAILS Of Uncertain Presence in Illinois 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 Illinois 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 ftoridana 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 Illinois is doubtful. It is rare in Michigan and is not recorded from Indiana. J ertigo gouldii 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 Illinois is to be questioned. The record is without doubt founded on specimens of Succinea retusa, which greatly resemble nuttalliana. [147] 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 Illinois by the author of this fieldbook. Succinea grosvenorii Lea. Page 114. This species was recorded by Nason and Wolf from Canton, Fulton County. The specimens thought by these men to be grosvenorii are now known to be minor variations of Succinea avara. Polygyra sayii (Binney), same as Polygyra sayana Pilsbrv. Page 115. Recorded from northern Illinois 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 parietal 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 mitchelUana (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 rnifchelliana 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 ?nitchelHana 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 shininji. The aperture is rounded in ruitchelliana, while it is transversely narrowed in peurisylvanica. Ornphaliua inornata (Say). Page 119. Now known as Alesornphix inornotus, 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 indent at a 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 bv 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 J'entridens 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 Marsli. The record is probably a case of mistaken identity. Gastrodonta interna occurs in southeastern Indiana, and its presence in Illi- nois is very doubtful. Bibliography BIBLIOGRAPHY THE 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 MoUusca. 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 Collins. 1902. The MoUusca oj the Chicago Area. Part II. The Gastropoda. Natural History Survey of the Chi- cago Academy of Sciences Bulletin 3(2). Chicago. Baker, Frank Collins. 1903. Shells of Land and Water. A Familiar Introduction to the Study of the Mollusks. A. W. Mum- ford, Chicago. Baker, Frank Collins. 1906. A Catalogue of the MoUusca of Illinois. Illinois State Laboratory of Natural History Bulle- tin 7(6) -.53-136. Urbana. Baker, Horace Burrington. 1925-39. Proceedings of the Academy of Natural Sciences of Philadelphia. (Numerous papers also in the Nautilus during the same period. Many im- portant changes in molluscan nomenclature are recorded in these volumes.) Baker, Horace Burrington. 1933. A Check List of Nearctic Zonitidae. University of Michigan Museum of Zoology Oc- casional Papers 269. Ann Arbor. Bartsch, Paul, and Mary Elaine Quick. 1926. "An Anatomic Study of Zonitoides arboreus (Say)." Journal of Agricultural Research 32(8) -.783-91. Washington, D. C. BiNNEY, William G. 1885. Manual of American Land Shells. United States National Museum Bulletin 28. Washington, D. C. BiNNEY, William G., and Thomas Bland. 1869. Land and Fresh Water Shells of North America. Part I. Pulmonata Geophila. Smithsonian Miscellaneous Collections 194. Washington, D. C. Blatchley, W. S., and L. E. Daniels. 1903. "On Some MuUusca 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. Call, Richard Ellsworth. 1900. "A Descriptive Illustrated Catalogue ot the MoUusca of Indiana." Annual Report for 1899, Department of Geology and Natural Resources of Indiana 24:335-535. Indianapolis. [153] 154 BIBLIOGRAPHY Clapp, George H. 1906. "Notes on Carychium and Description of a New Variety." Nautilus 19:138-40. Daniels, 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. Daniels, 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. Forbes, Edward, and Sylvanus Hanley. 1853. A History of British Mollusca and Their Shells 1. John Van Voorst. London. Foster, Thural Dale. 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. Goodrich, Calvin. 1932. The Mollusca of Michigan. Michigan Handbook Series 5. University of Michigan Press. Ann Arbor. MoRSE, Edward 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 Historv l(l):l-60. PiLSBRY, Henry Augustus. 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. PiLSBRY, Henry Augustus. 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.) PiLSBRY, H. A., and C. W. Johnson. 1898. "A Classified Catalogue with Localities of the Land Shells of America North ot 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, Victor. 1907. "A Preliminary Catalogue ot the Land and Fresh Water Mollusca of Ohio." Ohio State Academv of Science 4(8):367-402 (Special Paper 12). Tryon, George W. Jr., 1866-67. "Monograph ot the Terrestrial Mollusca of the L^nited States." American Journal of Con- chology 2:218-77, 306-27; 3:34-80, 155-74, "298-324." (Also published by the author in book form.) Van Cleave, Harley J., and Thural Dale Foster. 1937. "The Seasonal Life History of a Land Snail, Polygyra thvroidus (Say)." Nautilus Sl-.Sd-A. BIBLIOGRAPHY 155 Walker, Bryant. 1906. "An Illustrated Catalogue of the MoUusca of Michigan. Part I. Terrestrial Fulmonata (Land Shells)." State Board of Geological Survey Report for 1905: 431-531, Lansing. Walker, Bryant, 1928. The Terrestrial Shell-Bearing MoUusca of Alabama. University of Michigan Museum of Zoology Mis- cellaneous Publication 18. Ann Arbor. WiNSLOw, MiNA L. 1922. Notes on the Internal Lamellae of Carychium, University of Michigan Museum of Zoology Oc- casional Papers 128, Ann Arbor, W^iNSLOw, MiNA L, 1926, A Revised Check List of Michigan MoUusca. University of Michigan Museum of Zoology Oc- casional Papers 181, Ann Arbor, The only journal in America for the study of the MoUusca 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 MoUusca, Check List of Illinois Species and Index CHECK LIST OF ILLINOIS LAND SNAILS HELICINIDAE 39 Hendersottta A. J. Wagner 39 occulta (Say) 39 POLYGYRIDAE 40 Polygyra Say 41 dorfeuilliana (Lea) 44 tridenlata Iridenlala (Say).. . . 45 tridentata frisoni F. C. Baker. 45 Iridenlala bidenlala F. C. Baker 45 Iridenlala unidenlala F. C. Baker 45 Iridenlala edentilahris Pilsbry 45 fraudulenla (Pilsbry) 46 inflecla injlecla (Say) 47 inflecla media Pilsbry 47 inflecla edenUUa (Sampson). . 47 profunda profunda (Say) .... 48 profunda efasciala Walker. . . 48 albolabris albolabris (Say).. . . 49 albolabris alleni (Wetherby).. 49 albolabris denlnta (Tryon) ... 49 zaleta (Binney) 50 mullilineala multilineala (Say) 51 mullilineata algonquinensis Nason 51 multilineala alba Witter 51 multilineala rubra Witter 51 palliata (Say) 52 obslricta (Say) 53 appressa (Say) 54 fosteri F. C. Baker 54 elevata (Say) 55 Pennsylvanica (Green) 55 thyroidus (Say) 56 clausa (Say) 57 stenolrema (Ferussac) 58 hirsula (Say) 59 monodon (Rackett) 60 fralerna fraterna (Say) 61 fralerna cava Pilsbry and Vanatta 61 leporina Gould 62 BULIMULIDAE 63 Bulimulus Leach 63 dealbalus (Say) 63 ZONITIDAE 64 Mesomphix Rafinesque 65 cupreus (Rafinesque) 66 friabilis (W. G. Binney) 67 perlaevis vulgalus H. B. Baker 68 Retinella (Shuttleworth) Fischer 69 eleclrina (Gould) 69 wheatleyi (Bland) 70 rhoadsi (Pilsbry) 70 indenlata (Say) 71 Hawaiia Gude 72 minuscula (Binney) 72 Paravitrea Pilsbry 73 capsella (Gould) 73 significans (Bland) 74 Euconulus Reinhardt 75 fulvus (Miiller) 75 chersinus chersinus (Say). ... 76 chersinus polygyralus (Pils- bry) 76 Slriatura Morse 77 milium milium (Morse) 7 7 milium meridionalis (Pilsbry & Ferriss) 77 Zonitoides Lehmann 78 arboreus (Say) 78 nilidus (Miiller) 79 limatulus ("Ward" Binney).. 80 Venlridens W. G. Binney & Bland 81 ligerus (Say) 81 demissus (Binney) 82 ENDODONTIDAE 83 A nguispira Morse 84 allernata alternala (Say) 84 alter nata carinata (Pilsbry & Rhoads) 85 kochi (Pfeiffer) 85 Discus Fitzinger 86 cronkhitei anthonyi (Pilsbry) 86 palulus (Deshayes) 87 Helicodiscus Morse 88 parallelus (Say) 88 singleyanus inermis H. B. Baker 89 Punclum Morse 90 pvgfmaeum (Draparnaud). ... 90 HAPLOTREMATIDAE 91 Ilaplolrema Ancey 91 concavum (Say) 92 PUPILLIDAE 93 Gastrocopta Wollaston 94 armifera armifera (Say) 96 armifera similis (Sterki) 96 armifera affinis (Sterki). . . . . 96 armifera abbreviala (Sterki). . 97 contracta contracta (Say) 98 conlracla climeana Vanatta. . 98 holzingeri (Sterki) 99 pentodon pentodon (Say) 100 penlodon gracilis (Sterki). . . . 100 lappaniana (C. B. Adams).. . 101 corticaria (Say) 101 procera procera (Gould) 102 procera mcclungi (Hanna & Johnson) 102 Vertigo Draparnaud 103 morsei Sterki 104 ovata Say 105 venlricosa (Say) 105 elatior Sterki 106 tridenlata Wolf 106 milium (Gould) 107 Pupoides Pfeiffer 108 marginatus (Say) 108 Columella Westerlund 109 edentula (Draparnaud) 109 STROBILOPSIDAE 110 Strobilops Pilsbry HI labyrinthicalabyrinlhica {Sayi 111 labyrinthica virgo Pilsbry. . . .112 labvrinthica parielalis Pils- 'bry 112 affinis Pilsbry 113 aenea aenea Pilsbry 114 aenea micromphala Pilsbry.. 115 aenea spiralis Pilsbry 115 [159] 160 CHECK LIST VALLONIIDAE 116 Vallonia Risso 116 Pulchella (Mullr.-) 118 excenlrica Sterki 118 coslata (Miiller) 119 parvula Sterki 119 COCHLICOPIDAE 120 Cochlicopa (Ferussac) Risso 120 liihrica (Muller) 120 SUCCINEIDAE 121 Succinea Draparnaud 121 ovalis ovalis Say 122 ovalis optima Pilsbry 122 concordialis Gould 7. . . 123 avara avara Say 124 avara wardiana Lea 124 relusa retiisa Lea 125 retusa magister Pilsbry 125 retusa decampi Tryon 126 retusa illinoisensis Wolf 126 retusa peoriensis Wolf 126 salleana Pfeiffer 127 LIMACIDAE 128 Deroceras Rafinesque 128 gracile Rafinesque 129 agreste (Linnaeus) 130 PHILOMYCIDAE 131 Philomycus Rafinesque 131 carolinianus (Bosc) 131 Pallifera Morse 132 dor salts (Binney) 132 fosteri F. C. Baker, New Species 133 ELLOBIIDAE 135 Carychium Muller 135 exiguum (Say) 136 exile H. C. Lea 136 SPECIES INTRODUCED Oxychilus cellarium (Muller). . . . 139 Oxychilus lucidum (Draparnaud) 140 Opeas mauritianum (Pfeiflfer). . . 140 Limax maximus Linnaeus 141 Limax flavus Linnaeus 142 Testacella europaea de Roissy. . . 142 INDEX abbreviala, Gastrocopta armifera . ... 97 abrupta, Gastrocopta contracta 98 aenea aenea, Strohilop.'; 114 micromphala, Strobilops 115 spiralis, Strobilops 115 Strobilops 114 Strobilops aenea 114 affinis Gastrocopta armifera 96 Strobilops 113 agreste, Deroctras 130 Agriolimax 128 alba, Polygyra multilineata 51 albolabris albolabris, Polygyra 19, 49 alleni, Polygyra 19, 49 dentata, Polygyra 19, 49 Helix 19 Polygyra 4, 6, 9, 19, 20, 49 Polygyra albolabris 19, 49 algonquinensis, Polygyra multilineata 51 alleni, Polygyra albolabris 19, 49 alternata alter nata, Anguispira 84 Anguispira 83, 84 Anguispira alternata 84 carinata, Anguispira 85 Pyramidula 84 alticola. Columella 109 .4 nguispira 22, 84 alternata 83, 84 alternata alternata 84 alternata carinata 85 kochi 22, 85 Angular lamellae 93 A ngustula 107 anthonyi. Discus cronkhitei 86 Aperture of shell 4, 17, 18 Apex of shell 18 Apparatus, collecting 13 appressa, Polygyra 54 arboreus, Zonitoides 23, 78 armifera abbreviata, Gastrocopta 97 affinis, Gastrocopta 96 armifera, Gastrocopta . .'. 96 Gastrocopta 95 Gastrocopta armifera 96 similis, Gastrocopta 96 aurea, Succinea 148 avara avara, Succinea 124 Succinea 121, 124 Succinea avara 124 wardiana, Succinea 124 B Back of snail 3 Baker, F. C 14 Baker, H. B 25 Basal fold 93, 110 Basommatophora 37, 135 bidentata, Polygyra tridentata 45 Bifidaria 96 pentodon floridana 147 BiNNEY, Amos 25 BiNNEY, William G 25 Binomial system 19 Bland, Thomas 25 Blanks, field data 12 Body snail 4 whorl. 18 Breathing orifice 4 BULIMULIDAE 63 Bulimulus 63 dealbatus 63 c Cabinets, shell 14, 16 Calkins, W. W 26 campestris, Deroceras 130 capsella Paravitrea 73 Vitrea 73 carinata, Anguispira alternata 85 carolinensis 132 carolinianus, Philomycus 131 Cartilage of mouth 5, 6 Carychium 135 exiguum 135, 136 exile 136 cava, Polygyra fraterna 61 cellar ia, Vitrea 140 Zonites 140 cellarium, Oxychilus 139 cellarius, Oxychilus 140 chersinus cher sinus, Euconulus 76 Euconulus 76 Euconulus chersinus 76 polygyratus, Euconulus 76 Chitin 6 Circinaria 92 Clapp, George H 25 Class 20 Classification of snails 17 clausa Helix 57 Polygyra 57 climeana, Gastrocopta contracta 98 Cochlicopa 120 lubrica 120 COCHLICOPIDAE 120 Collar, mantle 4 Collecting apparatus 13 snails 11 Collectors of Illinois land snails. ... 25 Color of shells 18 Columella 109 alticola 109 edentula 109 Columellar lamella 93, 110 concavum, Haplotrema 6, 7, 91, 92 concordialis, Succinea 123 contracta abrupta, Gastrocopta 98 [161] 62 NDEX climeana, Gaslrocopta 98 contracla, Gaslrocopta 98 Gastrocopla 97 Gaslrocopta contracla 98 corticaria, Gaslrocopta 101 costata, Vallonia 116, 117, 119 Counties of Illinois 27 cronkhitei anlhonyi. Discus ^. . . . 86 Discus 86 cryplomphala, Retinella 71, 149 cuprea, Omphalina 66 cupreus, Mesomphix 64, 66 D dealbatus, Bulimulus 63 decampi, Succinea relusa 126 demissus, Venlridens 82 dentala, Polygyra albolabris 19, 49 Denticle 18 labial 18 parietal 18 peristomal 18 Deroceras 128 agresle 130 campestris 130 gracile 129 Discus 86 cronkhitei 86 cronkhitei anthonyi 86 Patulus 87 dorfeuilliana, Polygyra 44 dorsalis, Pallifera 132 E Economic importance of snails 23 edentala, Polygyra in flee ta 47 edentilabris, Polygra Iridenlata 45 edentula Columella 109 Pupa 109 edentulum, Sphyradium 109 efasciata, Polygyra profunda 48 Eggs, snail 9 elatior. Vertigo 106 electrina, Retinella 69 elevata, Polygyra 55 ELLOBIIDAE 135 ENDODONTIDAE 22. 83 Epidermis 17 Epiphragm 12 Euconulus 75 cher sinus 76 chersinus chersinus 76 cher sinus polygyratus 76 fulvus 75 europaea, Testacella 142 excentrica, Vallonia 118 exiguum, Carychium 135, 136 exile, Carychium 136 exoleta, Polygyra 50 Eye 3, 4 peduncles 3,4 F fallax, Polygyra 46 Family 20, 22 Feeding habits 5 Feelers 3 Ferriss hoe 13 Ferriss, J. H 26 Field data blanks 12 flavus. Limax 23, 142 fioridana Bifidaria penlodon 147 Gastrocopla penlodon 147 Fold basal 93. 110 lower palatal 93 palatal 110 upper palatal 93 Folds of shell 18 Food of snails 5, 7 Foot 4 Form of shells 17. 18 Foster, Thural Dale 19 fosteri Pallifera 133 Polygyra 19, 54 raterna cava, Polygyra 61 fralerna, Polygyra 61 Polygyra 61 Polygyra fralerna 61 fraudulenla, Polygyra 46 friabilis, Mesomphix 67 frisoni, Polygyra Iridenlata ... 17. 18. 45 fuliginosa, Zoniles 66 fulvus, Euconulus 75 G Gastrocopla 34, 94 armifera 95 armifera abhreviata 97 armifera a finis 96 armifera armifera 96 armifera similis 96 contracla 94. 97 contracla abrupla 98 contracla climeana 98 contracla contracla 98 corticaria 101 holzingeri 19. 99 penlodon 100 penlodon floridana 147 penlodon gracilis 100 penlodon penlodon 100 procera 102 procera mcclungi 102 procera procera 102 tappaniana 101 Gaslrodonla 81 gularis 82, 150 interna 150 interlexla 82. 150 Gastropoda 20. 33. 37 Genus 19. 20 Geological history, snails in 30 Glacial periods 30 GoLTLD. Augustus A 25 gouldii, \'ertigo 103, 147 gracile. Deroceras 129 gracilis. Gaslrocopta penlodon 100 grosvenorii. Succinea 124, 148 Growth lines, shell 18 gularis Gaslrodonla 82. 150 Venlridens 82. 150 INDEX 63 H Habitat illustrations. 8. 10. 21,24, 28. 31. 32 snail 9, 13 Habits, feeding 5 haliotidea, Testacella 143 haliotoidea, Testacella 143 hammonis, Vitrea 69 Haplotrema 91 concavum 6. 7, 91, 92 HAPLOTREMATIDAE 91 Hawaiia 72 kawaiensis 72 minuscula "2 Head, snail 3, 4, 5, 6 Helicina occulta 39 HELICINIDAE 39 Helicodiscus 88 parallelus 88 singleyanus 89 singleyaniis inermis 89 Helix 19 albolabris 19 clause 57 kawaiensis 72 minuscula 72 minutissima 90 monodon 60 perspectiva 87 pomalia 23 pygmaea 90 Hendersonia 39 occulta 39 higginsi, Succinea 148 Hills 29 HiNKLEY, A. A 26 hirsuta, Polygyra 59 Hodgson, C. S 26 Hoe, Ferriss 13 HoLZiNCER, John M 19 holzingeri. Gaslrocopta 19, 99 Hunting for snails 3 I Identifying snails 20 Illinois counties of 27 land snails, collectors of 25 map of 27 physiography of 26 rivers of 27 illinoisensis Succinea 126 Succinea retusa 126 Illustrations, habitat 8, 10, 21, 24, 28, 31, 32 indentata. Retinella 71 inermis, Helicodiscus singleyanus ... 89 inflecta edentata, Polygyra 47 inflecta, Polygyra 47 media, Polygyra 47 Polygyra 47 Polygyra inflecta 47 Infraparietal lamella 110 inornata, Omphalina 149 inornaius, Mesomphix 149 interna, Gaslrodonta 150 Interparietal lamella 110 inter texta, Gaslrodonta 82, 150 interlextus, Ventridens 82, 150 J Jaw 5,6 K kawaiensis Hawaiia 72 Helix 72 Kennicott, Robert 26 Keys 22 kochi, Anguispira 22, 85 L Labels 16 Labial denticle 18 labyrinlhica labyrinthica, Strobilops Ill parietalis, Strobilops 112 Strobilops 110, 111 Strobilops labyrinthica Ill virgo, Strobilops 112 laevigata, Zonites 68 Lakes 30 Lamella 18 angular 93 columellar 93, 110 infraparietal 110 interparietal 110 parietal 93, 110 Lea, Isaac 25 leai, Polygyra 61 leporina, Polygyra 62 leporinum, Lobosculum 62 ligerus, Ventridens 81 LIMACIDAE. . 128 limatulus, Zonitoides 80 Limax flavus 23, 142 maximus 23, 141 limpida, Vitrina 149 Linnaeus 19 LiNNE 19 Lobosculum leporinum 62 loessensis. Vertigo 106 Lower palatal fold 93 lubricn, Cochlicopa 120 lucidum, Oxychilus 140 M Macrocylis 92 magister, Succinea retusa 125 Mantle 4 collar 4 Map of Illinois 27 marginatus, Pupoides 108 Marsh, VV. A 26 Marston, George T 26 mauritianum, Opeas 140 maximus, Limax 23, 141 mcclungi, Gaslrocopta procera 102 media, Polygyra inflecta 47 meridionalis, Striatura milium 77 Mesomphix 65 cupreus 64, 66 164 INDEX friabilis 67 inornalus 149 perlaevis perlaevi;, 68 perlaevis vulgatus 68 microtnphala, Slrobilops aenea 115 milium meridionalis, Slriatura 77 milium, Slriatura 77 Slriatura 77 Slriatura milium 77 Vertigo 107 minuscula Hawaiia 72 Helix 72 yninusculus, Zonitoides 72 minulissima. Helix 90 mitchelliana, Polygyra 148 Mollusca, see snail or snails Mollusk, see snail or snails monodon Helix 60 Polygyra 60 Morse, Edward S 19 morsei. Vertigo 19, 104 Mouth 4, 5, 6 cartilage of 5, 6 Mucus 4 glands 6 tnultilineata alba , Polygyra 51 algonquinensis, Polygyra 51 multilineata, Polygyra 51 Polygyra 51 Polygyra Tnultilineata 51 rubra, Polygyra 51 muscorum, Pupilla 147 N Names, scientific 18, 19 Naming snails 18 Nason, W. a 26 nitidus, Zonitoides 79 nuttalliana, Succinea 147 o obstrida, Polygyra 53 occtdta Helicina 39 Hendersonia 39 Omphalina cuprea 66 OmphaUna inornata 149 Opeas mauritianum 140 optima, Succinea oralis 122 Order 20 Orifice, breathing 4 oval is optima, Succinea 122 ovalis, Succinea 122 Succinea 122 Succinea ovalis 122 ovata. Vertigo 105 Oxychilus cellar ium 139 cellar ius 140 lucidum 140 P Palatal fold 110 Palliata, Polygyra 40, 52 Pallifera 132 dorsalis 132 fosleri 133 parallelus, Helicodiscus 88 Paravitrea 73 capsella 73 significans 74 Parietal denticle 18 lamella 93, 110 wall 18 parietalis, Slrobilops labyrinthica . . . 112 parvula, Vallonia 119 patulus. Discus 87 Peduncles, eye 3, 4 pennsylvanica, Polygyra 55 pentodon floridana, Bifidaria 147 floridana, Gaslrocopta 147 Gaslrocopta 100 Gaslrocopta pentodon 100 gracilis, Gaslrocopta 100 pentodon, Gaslrocopta 100 peoriensis, Succinea retusa 126 Periods, glacial 30 Periostracum 17 Peristomal denticle 18 Peristome 18 perlaei'is Mesomphix perlaevis 68 perlaevis, Mesomphix .68 vulgatus, Mesomphix 68 perspectiva Helix 87 Pvramidula 87 PHILOMYCIDAE 131 Philomycus 131, 133 carolinianus 131 Physiography of Illinois 26 PiLSBRY, Henry A 25 Plain 29 Polvgvra 20, 22, 34. 41 albolabris 4, 6, 9. 10. 20. 49 albolabris albolabris 19. 49 albolabris alleni 19. 49 albolabris dentata 19, 49 appressa 54 claiisa 57 dorfeuilliana 44 elevata 55 exolela 50 fallax 46 'fosleri 19. 54 fraterna 61 fraterna cava 61 fraterna fraterna 61 fraudulenta 46 hirsuta 59 inflecia 47 inflecta edentata 47 inflecia inflecia 47 inflecta media 47 leai 61 leporina 62 mitchelliana 148 monodon 60 INDEX 165 multilineata 51 multilineata alba 51 muUilineala algonquinensis 51 multilineata multilineata 51 multilineata rubra 51 nbslricta 53 palliala 40. 52 pennsylvayiica 55 profunda 48 profunda efasciata 48 profunda profunda 48 pustula 62 sayana 1 48 sayii 1 48 stenotrema 58 thyroides 56 thyroidus 56 Iridenlata 7, 45 tridenlata bidentnla 45 tridentata edentilabris 45 tridentata frisoni 17, 18, 45 tridentata tridentata 45 tridentata unidentata 45 zaleta 50 polygyratus. Euconulus chersinus. . . 76 POLYGYRIDAE 20, 40 pomatia. Helix 23 Prairies 30 Preserving snails 15 procera Gastrocopta 102 Gastrocopta procera 102 mcclungi, Gastrocopta 102 procera, Gastrocopta 102 profunda efasciata, Polygyra 48 Polygyra 48 Polygyra profunda 48 profunda, Polygyra 48 Pronunciation of scientific names. . . 20 Prosobranchiata 37, 39 pulchella, Vallonia 118 Pulmonata 4, 20, 37, 40 Punctum 90 pygmaeum 90 Pupa 96 edentnla 109 simplex 109 Pupilla muscorum 147 PUPILLIDAE 93 Pupoides 108 marginatus 108 Pupoids 18, 23 pustula, Polygyra 62 pygmaea. Helix 90 pygmaeum, Punctum 90 Pyramidula alternata 84 perspectiva 87 solitaria 85 R Radula 5, 6. 7 Records 12 Reproduction of snails 9 Retinella 69 cryptomphala 71, 149 electrina 69 indentata 71 rhoadsi 70 u'healleyi 70 retusa decampi, Succinea 1 26 illinoisensis, Succinea 126 magister, Succinea 125 peoriensis, Succinea 126 retusa, Succinea 125 Succinea 125 Succinea retusa 125 rhoadsi, Retinella 70 Ribs of shell 18 Rivers of Illinois 2 7 rubra, Polygyra multilineata 51 s salleana, Succinea 127 Say, Thomas 19, 25 sayana, Polygyra 148 sayii, Polygyra 148 Scientific names 18, 19 pronunciation of 20 Sculpttire, shell 18 Selenites 92 Shell 3, 4, 17, 18 aperture of 4, 17, 18 apex of 18 cabinets 14, 16 folds of 18 growth lines 18 ribs of 18 sculpture 18 vials 14, 16 Shells color of 18 form of 17, 18 snails with _3 significans, Paravitrea 74 similis, Gastrocopta armifera 96 simplex Pupa 109 Vertigo 109 singleyanus Helicodiscus 89 inermis, Helicodiscus 89 Slug 5 Snail 3 back of 3 body 4 eggs 9 habitat 9. 13 head 3, 4 ,5, 6 Snails classification of 17 collecting 11 collectors of Illinois land 25 economic importance of 23 food of 5,7 hunting for 3 identifying 20 in geological history 30 naming 18 preserving 15 reproduction of 9 with shells 3 solitaria, Pyramidula 85 Species 19, 20 Sphyradium edentulum 109 spiralis, Slrobilops aenea 115 66 INDEX Spire 18 slenolrema, Polygyra 58 Slrialura 77 milium 77 milium tneridionalis 77 milium milium 77 Slrobila Ill Strobilops Ill aenea 114 aenea aenea 114 aenea micromphala 115 aenea spiralis 115 affinis _ 113 labyrinthica 110, 111 labyrinlhica labyrinthica Ill labyrinthica parietalis 112 labyrinthica virgo 112 STROBILOPSIDAE 22. 110 Strode, W. S 26 Stylommatophora 37, 40 Succinea 11, 121 aurea 148 avara 121, 124 avara avara 124 avara wardiana 124 concordialis 123 grosvenorii 124, 148 higginsi 148 iUinoisensis 126 nuttalliana 147 ovalis 122 ovalis optima 122 ovalis ovalis 122 retusa 125 retusa decampi 126 retusa iUinoisensis 126 retusa magister 125 retusa peoriensis 126 retusa retusa 125 salleana 127 vermeta 124 SUCCINEIDAE 121 Suture 18 System, binomial 19 T Tail 4 tappaniana, Gasirocopta 101 Tebennophorus 133 Teeth 6, 7. 18 Tentacle 3,4 Testacella europaea 142 haliolidea I43 haliotoidea 143 thyroides, Polygyra 56 thyroidus, Polygyra 56 Trays .' .' . .'.'.14, 16 Trematoda 25 tridentata bidentata, Polygyra 45 edentilabris, Polygyra 45 frisoni, Polygyra 17, 18, 45 Polygyra 7, 45 Polygyra tridentata 45 tridentata, Polygyra 45 unidentala, Polygyra 45 Vertigo 106 U Ulffers, H. a 26 Umbilicus ' ig unidentata, Polygyra tridentata 45 Upper palatal fold 93 V '^'alle>s 29 Vallonia j 15, coslata i 16,' \\i ,' \\9 excentrica ng parvula 119 pulchella ng VALLOXIIDAE '..'..'.'.'.'.'.116 ventricosa. Vertigo 105 Ventridens gi demissus ' g2 gularis .82, 150 intertextus 82. ISO ligerus ' gi vermeta, Succinea 124 Vertigo .....!' .103 elatior 105 gouldii 163, 147 loessensis iQ^i milium 107 morsei 19. 104 ovata .105 simplex ] 09 tridentata 1 06 ventricosa 105 Vials, shell 14. I6 virgo, Strobilops labyrinlhica ~. . 1 1 2 viridulus, Vitrea 70 Vilrea capsella 73 cellaria 1 40 hammonis 69 viridulus 70 Vitrina limpida 149 vulgatus, Mesomphix perlaevis 68 w Walker, Bryant 25 Wall, parietal ig u-ardiana, Succinea avara 124 ivheatlevi, Relinella 70 Whorl 13 body Ig Wolf, John 26 z zaleta, Polygyra 50 Zonites gl cellaria 140 fuliginosa 66 laevigata 68 ZOXITIDAE 22. 64 Zonitoides 23. 78 arboreus 23. 78 limatulus 80 minusculus 72 ui'idus 79 Zonitoids 13. 23