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THE MOLLUSCAN FAMILY PLANORBIDAE 



7? 17 



THE MOLLUSCAN FAMILY 
PLANORBIDAE 



By 

FRANK COLLINS BAKER . 

Curator, Museum of Natural History, ^m.tyiiu& 
University of Illinois 



Collation, Revision, and Additions 

By 
HARLEY JONES VAN CLEAVE 



THE UNIVERSITY OF ILLINOIS PRESS 
URBANA : 1945 



Published by the University of Illinois Press 
under the auspices of the Graduate School. 

Copyright, 1945, by the University of Ulinois 
Press. Permission for rejiroduction in any 
form mav be obtained from the Publisher. 




Manufactured in the United States of America 



PREFACE 

THE WIDE DISTRIBUTION, large number of species represented, 
and the economic significance from a medical standpoint, as inter- 
mcfliate hosts of flukes or trematode worms, constitute the family 
Planorbidae as one of the most important groups of fresh-water Mollusca. 
It is the largest and most conspicuous of the families of Basoramatophor- 
ous pulmonate snails. 

Unlike the terrestrial pulmonates (Stylommatophora Pulmonata) 
which have been brought to a high state of precise classification from the 
anatomical studies of Dr. Henry A. Pilsbry and his co-workers, the Basom- 
matophora are still in a condition of more or less chaos as regards classi- 
fication, all of the monographs and many of the local studies being based 
wholly or partly on characteristics of the shell with little regard for rela- 
tionships which might be gained by a study of the organization of the 
animal. The condition of this large group as far as classification is con- 
cerned is little better than that of the land snails seventy-five years ago. 

In 1911 the writer published a monograph of the Lymnaeidae of North 
and Middle America, basing the classification on characteristics of the 
genitalia and radula. In that work it was suggested that studies on 
Planorbis, Physa, and other groups might follow the publication of the 
Lymnaeidae volume if it should meet with the approval of the conchologi- 
cal public. That it is still in general use after an interval of more than 
thirty years is evidence that its reception has been, on the whole, of a 
favorable nature. 

The present volume on the Planorbidae was begun some twenty-five 
years ago and has been in active preparation for the past ten years. As 
the work progressed it became evident that adequate treatment of the 
subject could not be given in a volume similar to that on the Lymnaeidae 
and so the work has been divided into two parts, part I on the anatomy 
and classification of the family, and part II* on descriptions of the species 
of the family inhabiting North and South America and the West Indies. 

The study of the internal organization of the family Planorbidae has 
shown that, as in the case of the land snails, the anatomy gives the only 
true key to a natural classification. The shell alone cannot be relied upon 
for this purpose because some of the characteristics are often misleading, 
affording many cases of parallel development, as the presence of lamellae 
within the aperture, which feature is found in a number of groups which 
are unrelated anatomically. There are some shell characteristics, however, 
which are of value in classification when used in conjunction with ana- 
tomical features. 

For the anatomical studies recorded in this volume, eighty species and 
races of the family have been examined, represented by more than 725 
specimens. The anatomy of six additional species has been taken from the 
literature. The number of species examined has been divided among the 
four subfamilies as follows: Planorbinae 19; Segmentininae 11; Helisoma- 
tinae 41 ; Planorbulinae 10. A large majority of the known genera and 
subgenera are represented and it is confidently believed that additional 
anatomical study will not greatly alter the classification herein set forth. 

*See title page of Part II (page 213) for statement regarding change in scope of 
this part. 

ix 



X The Molluscan Family Planorbidae 

The anatomical drawings in this work have all been made by the author 
with the aid of the camera lucida, and the outlines and much of the detail 
of the figures are correct from the standpoint of dimensions. Some of 
the finer details have been filled in by hand on the camera lucida figure. 
All dissections were made with a Spencer binocular microscope with mag- 
nification up to seventy-five diameters. The radulae have all been examined 
under a Zeiss microscope with magnification up to about 1000 diameters. 

In order that the features of the different organs might be fully known 
they have been separated and otherwise dissected to bring out all rela- 
tionships. In many cases sections have been made through organs or 
groups of organs the better to show structural conditions. Some of the 
figures are diagrammatic, but in the majority of the figures the author has 
endeavored to portray the form of the organs as they appeared to him 
under the microscope. Only the shells of the type species of the different 
genera and subgenera are figured in the plates prepared for Part I. 

In the matter of bibliographic citations it has not been deemed neces- 
sary to include all references to works in which a genus or other group is 
listed or described. To have done this would have lengthened the work 
to a large degree without adding greatly to its value. Only the most im- 
portant citations, including the first one in which the generic name ap- 
pears, are included. It will be noted that many groups, which have been 
ignored or placed in the synonymy by previous authors, have been recog- 
nized in this work. This is particularly true of Asiatic groups which have 
been little known anatomically. Every generic or group name has been 
given careful study to ascertain its true relationship. 

All groups described in this work are arranged under the heading of a 
genus or of a subgenus, none as sections. Until a greater number of species 
have been examined for the internal organization this division appears 
best. Some of the groups herein considered genera may later be placed as 
subgenera. It does not at present appear to be of any advantage to recog- 
nize the terms section or subsection for any of the groupings. 

The list of species included in each genus or subgenus has no pretension 
to completeness, only those species being listed which have either been 
examined anatomically or appear from the form of the shell to be related. 
As additional material is examined some of the species listed may be 
shifted to other groups and additional species may be included. 

January, 1942 



ACKNOWLEDGMENTS 

IN LARGE ^MEASURE the successful preparation of this work has 
been due to the help and encouragement of many American concholo- 
gists and zoologists. The authorities of the United States National 
Museum at Washington, through the interest of Dr. Paul Bartsch, Curator 
of Recent and Cenozoic Invertebrates, have freely lent the collections of 
Planorbidae for study. Without this magnificent material, probably the 
largest assemblage of species of this family extant, it would have been 
imjiossible to understand the relationships of the American species of the 
family. ]Mr. William J. Clench, Curator of the Department of Mollusca, 
]\Iuseum of Comparative Zoology of Harvard University, supplemented the 
National Museum material by the loan of thousands of specimens, many 
of the series of species being incomparable in size and completeness. Both 
of these gentlemen have also contributed much anatomical material. Other 
individuals and institutions have lent or given specimens for both anatomi- 
cal and dry study. To all of these the writer is under the greatest obliga- 
tion. The list of those rendering assistance is given below: 

Dr. C. C. Adams, Director, State Museum of New York, Albany 

Dr. E. A. Andrews, Professor of Zoology (Retired), Johns Hopkins University, 

Baltimore 
Dr. H. BuRRiNGTON Baker, Professor of Zoology, University of Pennsylvania, 

Philadelphia 
Dr. John C. Bequaert, Professor, Harvard University Medical School, Cambridge 
Dr. Edward W. Berry, Professor of Paleontology, Johns Hopkins University, 

Baltimore 
Dr. S. Stillman Berry, Redlands, California 
Dr. Stanley T. Brooks, Curator of Lower Livertebrates, Carnegie ]\Liseum, 

Pittsburgh 
Dr. A. R. Cahn, formerly Associate Professor of Zoology, University of lUinois, 

Urbana 
Dr. E. P. Cheatum, Professor of Zoology, Southern IMethodist Universit}', Dallas 
Dr. William A. Clemens, formerly of the Pacific Biological Station, Nanaimo, B.C. 

Now Professor of Zoology, University of British Columbia, Vancouver, B.C. 
Miss Ruth E. Coats, Tellamoole, Oregon 
Dr. Ernest C. Faust, School of Tropical ^ledicine, Tulane University, New 

Orleans 
Mr. C. J. Firkins, Edwardsville, Illinois 
Dr. Thural Dale Foster,* University of Illinois, Urbana 
Mr. Calvin Goodrich, Curator of ]\Ioilusca, University of Michigan Museum, Ann 

Arbor 
Dr. G. D. Hanna, Curator of Paleontology, California Academy of Science, San 

Francisco 
Professor Junius Henderson,* Curator Emeritus, University Museum, Univer- 
sity of Colorado, Boulder 
Dr. L. G. Hertlein, Assistant Curator of Paleontology, California Academy of 

Science, San Francisco 
Mr. Shintoro Hirase,* Zoological Institute, Tok3-o, Japan 

Dr. William A. Hoffman,* School of Troi)ical Medicine, San Juan, Puerto Rico 
Mr. Leslie Hubricht, St. Louis Botanical Gardens, St. Louis, Missouri 
Mr. A. Jankowski, Warsaw, Poland 

Mr. A. LaRocque, Canadian Geological Survey, Ottawa, Canada 
Mr. John B. Litsey, Dallas, Texas 

*Deceased. 

xi 




xii The Molluscan Family Planorbidae 

Mr. Paul McGinty, Boynton, Florida 

Dr. Roy W. Miner, Curator, Department of Living Invertebrates, American 

Museum of Natural History, New York City 
Mr. William B. Marshall, formerly Assistant Curator of Mollusca (Retired), 

U.S.N.M., Washington, D.C. 
Dr. Paul R. Needham, Associate in Aquatic Biolog}^, U.S. Bureau of Fisheries 
Mr. Olof 0. Nylander, Caribou, Maine 
Dr. Henry A. Pilsbry, Curator of Mollusca, Academy of Natural Sciences, 

Philadelphia 
Dr. C. Ping, Fan Memorial Institute, Peiping, China 

Dr. Baini Prashad, Zoological Survey of India, Indian Museum, Calcutta, India 
Dr. H. S. Rao, Zoological Survey of India, Indian Museum, Calcutta, India 
Dr. D. S. Rawson, Professor of Zoology, University of Saskatchewan, Canada 
Dr. Harold A. Rehder, Assistant Curator, Division of Mollusca, U.S.N.M., 

Washington, D.C. 
Dr. Horace G. Richards, Academy of Natural Sciences, Philadelphia 
Mrs. Imogene C. Robertson, Buffalo Museum of Science, Buffalo 
Dr. Hugo G. Rodeck, Curator, University of Colorado Museum, Boulder 
Mr. W. F. Shay, Department of Science, Normandy High School, St. Louis 
Miss Elberta C. Smith, University of Colorado Museum, Boulder 
Mr. H. W. Smith, Atlantic Coast Biological Station, St. Andrews, New Brunswick 
Dr. Harley J. Van Cleave, Professor of Zoology, University of Illinois, Urbana 
Dr. Henry Van der Schalie, University of ^Michigan Museum, Ann Arbor 
Mr. T. VAN Hyning, Curator, State Museum, Gainsville, Florida 
Dr. Bryant Walker,* Detroit 
Dr. Alexander Wetmore, Assistant Secretary, Smithsonian Institution, in charge 

of U.S.N.M., Washington, D.C. 
Mr. Berlin H. Wright,* Penn Yan, N.Y., and Lakeland, Florida 

The writer is highly appreciative of the help given him by the Uni- 
versity of Illinois Library, not only for the volumes consulted in its stacks, 
but also for its aid in securing through the interlibrary loan system many 
rare volumes not in our own library. To jNIiss Fanny Dunlap the author is 
deeply indebted for this help. The libraries lending these books include 
the John Crerar Library, Chicago; Columbia University of New York; 
Johns Hopkins University, Baltimore; Harvard University, Cambridge; 
University of Michigan, Ann Arbor; Iowa State College, Iowa City; The 
U.S. Geological Survey, Washington, D.C; and the Congressional Library 
of AVashington, D.C. 

The photographs of the shells and the copies from author's works were 
all made in the Photographic Laboratory of the University of Illinois, 
under the direction of Mr. Ray R. Hamm, Manager of the Laboratory. 

The author desires to express his deep appreciation of the help given 
by Dean R. D. Carmichael, of the Graduate School of the University of 
Illinois, who has greatly aided in the preparation of the work by providing 
several grants of funds for the making of the photographic plates. Without 
this assistance this volume could not have been completed. f 

Frank Collins Baker 

*Deceased. 

tThe University of Illinois Press here records its appreciation of the assistance 
of Professor Harley J. Van Cleave, who, in addition to writing the 'Memorial' and 
compiling the bibliography attached thereto, has carefully checked the copy and the 
plates, including the legends, and has given many helpful suggestions on the typo- 
graphical and scientific arrangement of the data. Mrs. Katharine Hill Paul, artist in 
the Department of Zoology, has rendered valued service in making numerous altera- 
tions of the original drawings to ensure satisfactory engravings. — H.E.C. 



CONTENTS 

Preface ix 

Acknowledgments xi 

A Memorial to Frank Collins Baker (1867-1942) .... xvii 
A Chronological List of the Scientific Publications 

OF Frank Collins Baker xxv 

Original Articles and Books xxv 

Biographical Contributions xxxv 

Book Notices and Reviews xxxv 

PART I 

Classification and General ^Morphology 

I. General ^Morphology 3 

A. External Appearance of the Animal 3 

B. General Internal Anatomy 4 

(a) The Reproductive System 4 

(b) The Digestive System 9 

(1) The Jaw 10 

(2) The Radiila 11 

(c) The Renal System 12 

(d) The Circulatory System 13 

(e) The Respiratory System 14 

(f) The Nervous System 14 

(g) The [Muscular System 15 

C. The Shell 15 

II. General Ecology 17 

General Environmental Conditions 17 

Variations in Different Environments 18 

Locomotion 19 

Food 19 

Food for Other Animals 19 

Length of Life 20 

The Planorbidae as Hosts for Parasitic Worms 21 

III. XlDIFICATION AND EmBRYOLOGICAL DEVELOPMENT .... 25 

A. Development of Helisoma scolare (Jay) 25 

B. Nidification and Development in Other Species of Helisoma 28 

(a) Self-fertilization or Autofecundation 29 

(b) The Development of Helisoma 31 

(1) Helisoma trivolvis lentum (Say) 31 

(2) Helisoma trivolvis fallax (Haldeman) 32 

(3) Helisoma duryi nor male Pilsbry 33 

(4) Helisoma duryi eudiscus Pilsbry 34 

(5) Helisoma tenue calif orniense F. C. Baker .... 34 

(6) Other Records of Egg Laying 35 



Xlll 



59931 



xiv The Molluscan Family Planorhidae 

IV. Distribution in Time and Space 37 

A. Geological History and Distribution 37 

B. Geographical Distribution 38 

Dispersal of Species 39 

V. Historical Sketch of Classifications 41 

VI. A New Classification of the Family Planorbidae . 45 

General Discussion 45 

Anatomical Keys to Groups 46 

Systematic List of Genera and Subgenera Recognized in 

This Work 48 

VII. Systematic Account of the Subfamilies, Genera, and 

Subgenera — Recent and Fossil 50 

Subfamily Planorbinae H. A. Pilsbry, 1934 50 

Genus Planorbis Geoff roy, 1767 51 

Genus Anisus Studer, 1820 (Gray, 1847) 55 

Subgenus Anisus SS 57 

Subgenus Costorbis Lindholm, 1926 61 

Subgenus Bathyomphalus (Ag.) Charp., 1837 .... 62 

Genus Odontogyrorbis Lorenthey, 1906 64 

Genus Gyraulus (Ag.) Charp., 1837 65 

Subgenus Gyraulus SS 66 

Subgenus Torquis- Dall, 1905 72 

Genus Armiger Hartmann, 1840 75 

Genus Taphius H. and A. Adams, 1855 79 

Genus Tropicorbis Pilsbry and Brown, 1914 80 

Subgenus Tropicorbis SS 85 

Subgenus Obstructio Haas, 1939 85 

Subgenus Lateorbis F. C. Baker, New Subgenus ... 85 

Genus Afroplanorbis Thiele, 1931 86 

Genus Syrioplanorbis F. C. Baker, new name for 

Heterodiscus West 88 

Genus Biomphalaria Preston, 1910 89 

Genus Australorbis Pilsbry, 1934 90 

Genus Anisopsis Sandberger, 1875 94 

Subfamily Segmentininae F. C. Baker, New Subfamily ... 96 

Genus Segmentina Fleming, 1817 96 

Genus Hippeutis (Ag.) Charp., 1837 100 

Genus Polypylis Pilsbry, 1906 104 

Genus Helicorbis Benson, 1855 106 

Genus Trochorbis Benson, 1855 108 



Contents xv 

VII. Systematic Account of the Subfamilies — continued 

Subfamily Segmentininae F. C. Baker, New Subfamily — continued 

Genus Pingiella F. C. Baker, New Genus 109 

Genus Intha Annanclale, 1922 112 

Genus Drepanotrema Fischer and Crosse, 1880 114 

Subgenus Drepanotrema SS 118 

Subgenus Fossulorbis Pilsbry, 1934 118 

Genus Paraplanorbis Hanna, 1922 119 

Genus Platytaphius Pilsbry, 1924 120 

Genus Acrorbis Odhner, 1937 121 

Subfamily Helisomatinae F. C. Baker, 1928 123 

Genus Helisoma Swainson, 1840 123 

Subgenus Helisoma SS 124 

Subgenus Seminolina Pilsbry, 1934 129 

Subgenus Pierosoma Dall, 1905 134 

Subgenus Planorbella Haldeman, 1842 150 

Genus Carinifex ^Y. G. Binney, 1863 154 

Genus Vorticifex :Meek, 1870 159 

Genus Perrinilla Hannibal, 1912 160 

Genus Parapholyx Hanna, 1922 161 

Genus Pompholopsis Call, 1888 165 

Genus Planorbarius Froriep, 1806 166 

Subfamily Planorbulinae Pilsbry, 1934 172 

Genus Planorbula Haldeman, 1840 172 

Subgenus Planorbula SS 173 

Subgenus Haldemanina Dall, 1905 177 

Genus Promenetus F. C. Baker, 1935 178 

Genus Menetus H. and A. Adams, 1855 182 

Subgenus ^lenetus SS 183 

Subgenus ]\Iicromenetus F. C. Baker, New Subgenus . 187 

Genus Planorbifex Pilsbry, 1934 190 

VIII. Groups of Uncertain Affinities 192 

Subfamily Choanomphalinae Germain, 1923 192 

Genus Choanomphalus Gerstfeldt, 1859 192 

Genus Poecilospira Morcli, 1853 194 

IX. Family Bulinidae 196 

Genus Indoplanorbis Annandale and Prashad, 1920 . . . 196 

X. Genera Wrongly Referred to Planorbidae 202 

Genus Nautilinus :\Iousson, 1872 202 

Genus Palaeorbis Beneden and Coemans, 1867 202 

XI. Bibliography 204 



xvi The Molluscan Family Planorbidae 

PART II 

The Planorbidae Inhabiting North and South America 

AND THE West Indies 

XII. Foreword 215 

XIII. Descriptions of New Species and New Varieties. . 218 

Genus Troyicorhis 218 

Tropicorbis shimeki, New Species 218 

Genus Helisoma 219 

Helisoma nnceps anticostianum, New Variety 219 

Helisoma anceps bartschi, New Variety 219 

Helisoma anceps idahoense, New Variety 220 

Helisoma anceps politum, New Variety 221 

Helisofna binneyi randolphi, New Variety 221 

Helisoma caribaeum cubense, New Variety 222 

Helisoma columbiense, New Species 222 

Helisoma kennicotti, New Species 223 

Helisoma pilsbryi preblei, New Variety 224 

Helisoma subcrenatum perdisjunctum, New Variety . . . 224 

Helisoma trivolvis marshalli, New Variety 225 

Helisoma campanulatum dalli, New Variety 226 

Helisoma campanulatum pleistocenicum, New Variety . . 226 

Helisoma campanulatum rideauense, New Variety . . . 227 

Genus Parapholyx 227 

Parapholyx effusa dalli, New Variety 227 

Parapholyx klamathensis sinitsini, New Variety .... 228 

Parapholyx pusilla, New Species 229 

Genus Planorbida 229 

Planorbula smithii, New Species 229 

Genus Menetus 230 

Menetus color adoensis, New Species 230 

Menetus cooperi crassilabris, New Variety 230 

Menetus cooperi planospirus, New Variety 231 

Menetus dalli, New Species 231 

Menetus dilatatus floridensis. New Variety 232 

Menetus labiatus, New Species 232 

Menetus portlandensis, New Species 233 

Illustrations of the Anatomy and of Shells 235 

Index to Text 521 

Index to Illustrations 527 



A MEMORIAL TO 
FRANK COLLINS BAKER 

(1867 to 1942) 

FRANK COLLINS BAKER became Curator of the Museum of 
Natural History in the University of IlUnois on January 1, 
1918. From that date onward until his death on May 7, 1942, 
his chief interests centered around his work and his associations on 
the L'rbana campus. Though he carried on extensive field studies 
during these years, they were chiefly summer vacation employment, 
and Urbana remained the focal point of his attention and activity. 
His appointment as Curator of the L'niversity ]^Iuseum gave him 
the opportunity to cooperate in the development of a museum de- 
voted primarily to teaching. To this work he brought a broad back- 
ground of professional experience in every aspect of museum work 
and at the same time drew freely from his research experiences to 
create on the L'rbana campus a series of collections and exhibits the 
prime purpose of which was ever that of aiding in student instruc- 
tion. As in all good teaching one of the first requisites is that of 
enlisting responsive interest by attractive presentation of fact or 
material, so likewise in his displays interest was always sought 
though it was never purchased by cheapening spectacular showman- 
ship. In his synoptic display of the animal series, the dry framework 
of classification became clothed by artistic and balanced organization 
of his materials. Groups represented only by fossil remains were 
treated as integrated with modern expressions of life, not as isolated 
representations of a dead past. 

For one whose career never placed him before classes for deliver- 
ing formal instruction, he gave evidence of keen appreciation of the 
museum as a supplement to laboratory and classroom teaching, and 
at all times offered hearty cooperation to the teaching faculty in 
creating habitat groups and other exhibits embodying both specific 
detail and broad principle. Under his curatorship the Museum of 
Natural History became utilized by diverse student groups. Biology, 
geology, and geography students found the displays meaningful; 
students in agriculture came to study the well-organized habitat 
groups of pests of farm crops, and art students frequented the exhi- 
bition halls for sketching. 

^Ir. Baker's concept of the functions of a museum combined not 
alone the aspects of display and instruction but a third objective as 
well, namely, that of research. Throughout his curatorship. he la- 
bored to establish and organize research collections. Naturally, the 
fields of his own interests were most emphasized and these included 
such diverse interests as the ]\Iollusca. archeology, and paleontology. 

xvii 



xviii The Molluscan Family Planorbidae 

In certain specialized areas of these three fields, the University col- 
lections have assumed a significance greater than might be expected 
in a small museum. The collections of Mollusca are especially rich 
in representatives of the fresh-water and land Mollusca, the direct 
result of Mr. Baker's active research program. Extensive field col- 
lecting was particularly stimulated by his association with the 
Natural History Survey of Wisconsin in the preparation of his ex- 
haustive two-volume work on the Mollusca of Wisconsin (1928). 
His long association and collaboration with the Illinois State Natural 
History Survey gave him access to extensive collections, especially 
in late years when he was engaged in an intensive field study of the 
land snails of Illinois which culminated in the Fieldbook of Illinois 
Land Snails published (1939) by the State Natural History Survey. 
A revival of interest in researches on the archeology of the State by 
the University resulted in amassing within the Natural History 
Museum huge quantities of pottery and artifacts for the care of 
which Mr. Baker became responsible. 

His early interest in the Pleistocene fauna was revived and. 
stimulated by a cooperative program of studies inaugurated by the 
State Geological Survey. Enormous series of Pleistocene material in 
quantitative samples were studied by Mr. Baker, whose services in 
cooperation with the State Geological Survey were recognized by his 
appointment to the position of Consultant in Pleistocene Paleon- 
tology on its staff (1919). The Pleistocene collections under this 
joint arrangement between Museum and Survey assumed great im- 
portance and wide reputation as repository of critical materials, and 
numerous collectors throughout the country sent samples for critical 
determination. Thus, at the time of Mr. Baker's death, the Pleisto- 
cene collections, which are now deposited in the State Geological Sur- 
vey, had become one of the significant study collections in this field. 

Mr. Baker's interest in research was deep and genuine, and the 
esteem with which his results are held gives evidence of the effective- 
ness of his activities in scholarly pursuits. His earliest studies on 
Mollusca were, in keeping with that period, restricted largely to the 
study of the shells but he early became an advocate of the study of 
the soft parts of the living animal which produces the shell and the 
volume which this sketch accompanies is the culmination of his pro- 
gram of anatomical studies. New apparatus and improved optical 
equipment made him often express the regret that he could not go 
back and do again all the earlier studies which he carried on with 
less adequate laboratory equipment. 

Early in his career as a student of Mollusca, Mr. Baker by his 
own collecting and by personal exchange, began amassing a private 
collection of fresh-water Mollusca. This collection centered around 
his chief interest, the fresh-water pulmonate snails. The operation of 
the old adage. To him who hath shall be given,' here finds exempli- 
fication, for students of Mollusca regularly sent doubtful specimens 



Memorial and Bibliography xix 

to him for classification or verification, and samples of those sub- 
mitted were added to his cabinet. At the time of his death, the two 
families Lymnaeidae and Planorbidae were particularly well repre- 
sented in the Baker Collection, which, as indicated elsewhere in this 
volume, was presented to the United States National Museum. 

A member of many scientific societies, he cherished particularly 
the election as Corresponding Alember of the Zoological Society of 
London. He was a fellow of the Geological Society of America and 
likewise of the Paleontological Society of America. At the time of 
his death he was president of the American Malacological Union. 
Other societies in which he held membership include: American 
Association of Museums, Museum Association of Great Britain, 
Ecological Society of America, American Limnological Society, Ot- 
tawa Field Naturalist's Club, and Sigma Xi. He was a fellow of the 
American Association for the Advancement of Science and held life 
membership in the Chicago Academy of Sciences and in the Illinois 
State Academy of Science. 

With the years, his zeal for research never waned. In fact, gradu- 
ally increasing deafness which tended to shut him off from an earlier 
appreciation of music and from easy communication with his friends 
gave him opportunity for uninterrupted study in which he could 
become so completely immersed as to ignore surrounding distrac- 
tions entirely and to forget adversities, even when he faced some of 
life's greatest tragedies. 

These statements regarding Mr. Baker, as a man and a scientist, 
would not be complete without some narration of his early years and 
background. 

Frank Collins Baker, son of Francis Edwin and Anna Collins 
Baker, was born in Warren, Rhode Island, on December 14, 1867. 
His family later moved to Providence, and there the boy received his 
early education and for a time attended a business college. Still 
struggling between the alternatives of business and science as a 
career, he was for a time employed by the Gorham Silversmiths, and 
there he learned the techniques of exactness and accuracy which he 
later maintained were of value in his scientific work. 

He attended Brown University for one year (1888-89). Even be- 
fore this time he had developed a consuming interest in shells which 
he often remarked were the favorite childhood toys brought to him 
from distant oceans by a seafaring grandfather. He left Brown to ac- 
cept the Jessup Scholarship (1889-91) in the Philadelphia Academy 
of Sciences and there, at the fountainhead of molluscan studies, the 
die was cast for his scientific career. In later years he often referred 
to the inspiration which he obtained from mere proximity to Joseph 
Leidy and other notables in the library and in the programs of the 
Academy. There likewise he became associated with H. A. Pilsbry, 
and the tradition for sound molluscan studies, which has always been 
an important aspect of the Academy program, gripped him. 



XX The Molluscan Family Planorhidae 

In 1890, Air. Baker, as zoologist, was a member of an exploring 
party from the Philadelphia Academy into Mexico. The travels in 
Cuba, Yucatan, and ^Mexico afforded by this expedition had on him 
the same broadening influence which travel has brought to all the 
great naturalists and inspired him to consider natural faunal areas 
instead of political units in subsequent programs of comprehensive 
taxonomic studies. Thus his monograph on the Lymnaeidae (1911) 
was not confined to the boundaries of the United States but encom- 
passed a more natural zoogeographical scope of 'North and ^Middle 
America.' and the program on the Planorbidae, results of which are 
embodied in this volume, was extended to include even broader scope 
in order to secure comprehensive treatment of a taxonomic unit 
without reference to political subdivisions. After his return from 
Mexico, Mr. Baker published his first separate book (1895), a small 
popular work entitled 'A Naturalist in Mexico,' which wove to- 
gether a narrative of the trip, a description of the country, and 
scientific observations. 

An intimate correspondence with Henry A. Ward of Rochester, 
part of which has been available to the present writer, ended in an 
arrangement wherein Mr. Baker was to become associated (1891) as 
Invertebrate Zoologist with the influential Ward's Natural Science 
Establishment. Few strictly educational institutions in the early 
history of this country have wielded the influence exerted by this 
private concern in the training of natural scientists, especially those 
headed toward museum work as a profession. While residing in 
Rochester, he became a frequent visitor in the home of John Hall. 
On June 12, 1892, he married Lillian Alay Hall who was his con- 
stant companion until her death in 1934. 

While his employment by the Ward Establishment was primarily 
for the identification and organization of the Ward collections of 
Mollusca, Mr. Baker at the same time selected and organized an 
extensive synoptic display of museum specimens representing all the 
groups of the invertebrates, which was being prepared for exhibition 
at the Chicago World's Columbian Exposition in 1893. Upan com- 
pletion of this task, Mr. Baker accompanied the exhibit to Chicago 
where he supervised its installation. At the close of the Exposition, 
the Ward exhibit was purchased by Marshall Field as part of the 
nucleus for the beginning of the Field Columbian Museum, and Mr. 
Baker was engaged as curator in the newly established museum 
(1894). But that same year he was chosen curator of the old, long 
established Chicago Academy of Science, w^here he succeeded and 
had association with men of the calibre of Robert Kennicott, William 
Stimpson, and T. C. Chamberlin. It was here that he perfected the 
techniques of museum display and administration and for the first 
time had opportunity to develop an intensive program of research, 
integrated with his professional work. Unfortunately, after about 
two decades with the Academy, a change in administration placed 



Memorial and Bibliography xxi 

the Academy in the hands of an individual who acrimoniously op- 
posed the place of research as a museum function. Even this adverse 
atmosphere brought no reduction in the research program which Mr. 
Baker had embarked upon, for nights and holidays were free from 
dictatorial domination. Some measure of his accomplishment during 
the Chicago period is available in the larger monographs which 
punctuated the continuous stream of smaller contributions from his 
desk. Three of his outstanding volumes were published during the 
twenty-one years of Mr. Baker's association with the Chicago Acad- 
emy. These are: two volumes on the Mollusca of the Chicago Area 
(1898 and 1902) and the monograph on the Lymnaeidae (1911). 
Another undertaking of particular importance — The Life of the 
Pleistocene — was virtually completed during the years with the Chi- 
cago Academy. However, publication of this volume was not afforded 
until after Air. Baker came to the University of Illinois (1920), and 
it was then published by the University Press. The work on this 
volume marked a new epoch in his research program. Stimulated by 
an intimate and cordial relation with Professor T. C. Chamberlin 
of the University of Chicago, Mr. Baker's personal interest in re- 
search swung toward the study of faunas of the past and interpreta- 
tion and reconstruction of environmental conditions under which 
they existed. The material which served as the original basis for this 
study was made available in unusual quantity by construction of the 
Chicago Drainage Canal. Apparently endless material was exposed 
by the dredging operations, but much of this opportunity for research 
would have been lost had it not been for ]\Ir. Baker's close personal 
attention to the dredging as it proceeded. Exposure which he experi- 
enced at that time led to infections which affected his hearing. 
Conditions there established became progressively worse until in 
later life his hearing was very seriously impaired. 

While with the Chicago Academy, ]\Ir. Baker developed a service 
feature w^hich has become an important aspect of most public mu- 
seums today and links them closely with the educational program. 
He began the construction of small portable displays of habitat 
groups for loan to public schools, thus taking the educational influ- 
ence of the museum into the schools rather than depending wholly 
on the unilateral relation of expecting the schools to send their pupils 
to the museum. The interest in children, and in education, developed 
by these contacts always remained with him. In the museums under 
Mr. Baker's direction, the urchin was as welcome a visitor and was as 
thoughtfully treated as the scholar. Thus, though he never held 
formal appointment as instructor in any educational institution, he 
exerted marked influence, and a number of present-day scientists 
trace the awaking of their interest to his kindly encouragement and 
enthusiastic attitude toward the field of science. Graduate students 
in the University of Illinois always found him inspiring and helpful 
when they approached him with their problems. 



xxii The Molluscan Family Planorbidae 

Mr. Baker found deep satisfaction in following the careers of men 
who attributed part of their early zeal for science to boyhood con- 
tacts with him and to inspiration growing out of his enthusiasm and 
kindly interest in their personal problems. One instance of an influ- 
ence of which he was personally unaware stands out prominently. A 
mother called at his office in Urbana to present him with a copy of a 
scientific book written by her son. She explained that the son, who 
had died while on archeological explorations in a foreign land, defi- 
nitely attributed his aspiration in the field of science to the benevo- 
lent and gracious attention of Air. Baker to the queries of an un- 
known and apparently unpromising urchin frequenting the museum 
of the Chicago Academy. 

Mr, Baker resigned from his position with the Chicago Academy 
in 1915. In that same year, he embarked on a new phase of his career 
in which his time was given over entirely to field study and research. 
The newly established New York State College of Forestry, on the 
campus of Syracus University, employed him as an investigator. For 
two years he carried on a comprehensive evaluation of the relations 
of bottom fauna to fish life in Oneida Lake. This program culmi- 
nated in two volumes of distinctive contributions which were pub- 
lished by the New York State College of Forestry. 

Ever since the founding of the University of Illinois, the Museum 
of Natural History had been in charge of members of the faculty 
whose foremost obligation had been that of teaching or administra- 
tion. Under wise guidance of men such as S. A. Forbes and Frank 
Smith, the Museum had prospered and was able to secure the serv- 
ices of very unusual collectors and competent preparators w^ho 
added materially to its development. Toward the end of President 
James's administration, a renewed interest in archeology and in 
natural resources together with rapid increase in University enroll- 
ment led to consideration of the problem of securing a full-time 
curator for the Museum of Natural History. The position was offered 
to Mr. Baker w^ho, at the height of his professional career, entered 
upon his duties in January, 1918. 

In 1936 Air. Baker reached the age established by the University 
for retirement from active service but his good health and vigor 
and the best interests of the University combined to bring about 
postponement of his retirement for three additional years. In 1939, 
in his seventy-second year, his colleagues helped him celebrate 
entrance upon status as Curator Emeritus, which permitted him to 
devote his entire time to completion of researches in progress. Let- 
ters of congratulation and appreciation from colleagues and from 
fellow scientists throughout the country were assembled, bound, 
and presented to him at a dinner in his honor. The esteem with 
which he was held as an individual and acknowdedgments of personal 
debts of gratitude were as sincely expressed as was the evaluation 
of his scientific work. 



Memorial and Bibliography xxiii 

Soon thereafter, illness impaired his opportunity for continuous 
work in the laboratory, but even under this physical handicap he 
continued to devote all the time that his strength would allow to 
the final studies for and preparation of the manuscript for his 
nuu/nuifi opus — the monograph on The Molluscan Family Plan- 
orbidae. Volume 1. based on exhaustive anatomical researches, was 
ready for the editor and work was progressing on Volume II when he 
was taken critically ill and hospitalization for surgery was unavoid- 
able. Following the operation he never regained his health but 
became rapidly weaker and died on May 7, 1942. 

Slight in stature, unpretentious in attitude, mild in disposition, 
and kindly, charitable, and unbiased in all of his personal and pro- 
fessional relations, Mr. Baker has left an undying impression of 
honesty, integrity, and genuineness in the memories of his many 
friends and associates. 

For more than half a century (1889-1942) Mr. Baker continued 
to publish the results of his researches and observations. Aside from 
purely incidental notes and compilations, which he continued to pub- 
lish throughout his career, his early publications dealt largely with 
distributional studies and problems of taxonomy of the MoUusca. 
Relatively early he began to shift his interest in Mollusca from 
purely conchological to malacological lines (about 1897) when he 
began to study the radulae and anatomy of the soft parts of the 
molluscs. The interest in Pleistocene paleontology first found expres- 
sion in a paper published in 1898 and continued through the rest of 
his life with two posthumous papers on this subject. 

Faunal studies with considerable attention to ecological relations 
of the molluscs began early and found particular expression in his 
monograph on the Lymnaeidae (1911) and in his ecological studies 
on the fauna of Oneida Lake. These studies stand as background to 
the interest which found final expression in his contributions as asso- 
ciate editor of Xaturalist's Guide to the Americas (1926). 

His long identification with the program of molluscan studies, 
kindly personal qualifications, and familiarity with the history of the 
subject led to his being commissioned to prepare biographical 
sketches for five of the distinguished students of Mollusca in the 
Dictionary of American Biography (Gould, 1929; Kennicott, 1930; 
Stimpson. 1932; Tryon, 1933; and Sterki, 1933). 

Interest in museum administration found expression in a series 
of papers issued during his years with the Chicago Academy and 
was revived when he became established in the museum at the 
University of Illinois. 

His publications in archeology were stimulated by his responsi- 
bility for the University collections and were concerned largely with 
analysis of shells and other remains of animal life encountered in 
excavations of Indian village sites in the Middle West. In this aspect 



xxiv The Molluscan Family Planorbidae 

of his work, he collaborated with various specialists but had closest 
relations with the late W. K. Moorehead whose reports on studies 
conducted for the University of Illinois were edited by Mr. Baker. 

To supplement this analysis it should be recorded that in the 
period from 1900 to 1915. Mr. Baker edited the Bulletins and other 
publications of the Chicago Academy of Sciences. From 1913 to 1915 
he was assistant editor of Home and School Reference Work, pub- 
lished in Chicago in seven volumes, to which he personally con- 
tributed 125 articles on birds. Earlier (1900) he prepared a one-page 
article on Mollusca for the United Editors Encyclopedia published in 
New York. In 1926, in addition to serving as associate editor of 
Naturalist's Guide to the Americas, he prepared the references 
therein to molluscan distribution. From 1921 to 1926, Mr. Baker 
wrote numerous reviews of current works on Mollusca for Ecology. 

In his total contributions, exceeding 350 original articles, more 
than 250 deal entirely or largely with his chosen field of research, 
the Mollusca. While many of these are but short, minor notes, some 
quantitative evaluation of Air. Baker's productivity may be reflected 
in the fact that more than a dozen of these works enumerated are 
of such size as to merit classification as separate books. 

Throughout his active career Mr. Baker kept a carefully compiled 
record of his publications, a copy of which was in his desk at the time 
of his death. This list, which he prepared, is here published in full 
with but few slight editorial changes and corrections. 

Harley Jones Van Cleave 



A CHRONOLOGICAL LIST OF THE 

SCIENTIFIC PUBLICATIONS OF 

FRANK COLLINS BAKER 

ORIGINAL ARTICLES AND BOOKS 

1889 

1. Conchology department in 'The Old Curiosity Shop' (of which department the 

writer was editor). Cahfornia. 

2. Notes on Florida shells. Nautilus, 3:53-54. 

3. Description of a new species of Ocinebra. Op. cit., 3:80-81. 

4. A few notes oi;i ornithological collecting. Oologists Exchange, New York, 2(9). 

5. Notes on the food of birds. Proc. Acad. Nat. Sci. Philadelphia, 1889:266-270. 

6. Remarks upon the round-tailed muskrat, Neofibcr allcni True. Op. cit., 1889: 

271-273. 

1890 

7. On the Indian River, Florida. Oologists Exchange, 3(11). 

8. Directions for collecting alcoholic specimens of the Mollusca. Old Curiosity Shop, 

9(3). . ^ 

9. Remarks on Urosnlpinx perrugatus Conrad. Nautilus, 4:29-30. Also m Proc. 

Acad. Nat. Sci. Philadelphia, 1890:46-47. 

10. On the modification of the apex of Murex. Proc. Acad. Nat. Sci. Philadelphia, 

1890:66-72. 

11. A catalogue of conchological abbreviations. Nautilus, 4:89-91, 115-117. 

1891 

12. Notes on a collection of shells from southern Mexico. Proc. Acad. Nat. Sci. 

Philadelphia, 1891:45-55. 

13. Descriptions of new species of Muricidae, with remarks on the apices of certain 

forms. Proc. Rochester Acad. Sci., 1:129-137. 

14. Remarks on the Muricidae with descriptions of new species of shells. Proc. Acad. 

Nat. Sci. Philadelphia, 1891:56-61. 

15. Catalogue and synonymy of the recent species of the family Muricidae. Proc. 

Rochester Acad. Sci., 1:153-172. 

16. The caves of Yucatan. Op. cit., 2:2. 

17. Notes on a collection of shells from the Mauritius; with a consideration of the 

Genus Magilus of Montfort. Op. cit., 2:19-40. 

18. Catalogue of specimens of Echinodermata, corals, gorgonians, and sponges. 

Ward's Natural Science Establishment, Rochester, N.Y., iv -f- 82 pages. 

1894 

19. Further notes on embryonic whorls of the Muricidae. Proc. Acad. Nat. Sci. 

Philadelphia, 1894:223-224. 

1895 

20. A glance at the Chicago Academy of Sciences. Nautilus, 8:109-111. 

21. The geographic distribution of ttie Mollusca. Science (n.s.), 2:179-183. 

22. Preliminary outline of a new classificatioii of the Muricidae. Bull. Chicago Acad. 

Sci., 2:169-189. 

23. Syllabvis of biological lectures. (Delivered before the North Side Science Section 

of the Chicago Institute of Education). Chicago. 

24. A naturalist in Mexico: being a visit to Cuba, northern Yucatan, and Mexico. 

Chicago, 1895 : viii + 145 pages. 

25. Thirty-eighth annual report of the Chicago Academy of Sciences. For the year 

1895. 16 pages. 

1896 

26. On the correct position of the aperture in Plajiorbis. Jour. Cincinnati Soc. Nat. 

Hist., 19(1) :45-48. 

27. Notes on the mental development and intelligence in animals. The Observer, 

1896:680-682. 

XXV 



xxvi The Molluscmi Family Planorhidae 

1897 

28. Thirty-ninth annual report of the Chicago Academy of Sciences. For the year 

1896. 26 page-s. 

29. On the pulsations of the molluscan heart. Jour. Cincinnati See. Nat. Hist., 19(2) : 

73-78. 

30. Note on Natrix grahami B. and G. (With F. M. Woodruff). Science (n.s.), 5:447. 

31. On the effect of music on caged animals. Amer. Nat., 1897:460-463. 

32. Critical notes on the Muricidae. Trans. Acad. Sci. St. Louis, 7:371-391. 

33. On the modification of the apex in gastropod mollusks. Ann. New York Acad. 

Sci., 9:685-704. 

34. On a collection of mollusks from Grand Tower, Illinois. Nautilus, ll(3):28-30. 

35. Further notes on animal intelligence. The Obseryer, 8:193-194. 

36. Collecting about Chicago. Sports Afield, 19(2) :112-113. 

37. Reason among animals. Op. cit., 19:276-278. 

38. Notes on Radulae. Jour. Cincinnati Soc. Nat. Hist., 19(3) :81-93. 

1898 

39. Do cats remember? Sports Afield, 20:215. 

40. The molluscan fauna of western New York. Trans. Acad. Sci. St. Louis, 8(5) : 

71-94. 

41. Collecting in Florida. Sports Afield, 20:314-316. 

42. Notes on mollusks from Acadia, Missouri. Nautilus, 11:36. 

43. Fortieth annual report of the Chicago Academy of Sciences. For the year 1897. 

27 pages. 

44. The Mollusca of the Chicago area.- Part L The Pelecypoda. Chicago Acad. Sci., 

Nat. Hist. Suryey Bull., 3(1):1-130. 

45. A day on the Chicago drainage canal. Nautilus, 12(6) :63-65. 

46. A new Sphaerium. Op. cit., 12:65-66. 

1899 

47. Collecting fresh-water shells. Popular Sci., 33(5) :99-100. 

48. Notes on the mollusks of Lilycash Creek. Nautilus, 13(3) :30-31. 

49. Study of fresh-water mussels. Popular Sci., 33:194-197. 

50. Notes on the Mollusca of Owasco Lake, New York. Nautilus, 13:57-59. 

1900 

51. Notes on a collection of Pleistocene shells from Milwaukee, Wisconsin. Jour. 

Cincinnati Soc. Nat. Hist., 19:175-177. 

52. On a collection of fresh-water .shells from Rhode Island. Nautilus, 13:112-113. 

53. A new museum tablet. Amer. Nat., 34:283-284. 

54. The rock shells. Birds and Nature. 7:191-192. 

55. The gross anatomy of Limnnca cmarginata Say, yariety Mighehi Binney. Bull. 

Chicago Acad. Sci., 2(3) : 191-211. 

56. A reyision of the Physae of northeastern Illinois. Nautilus, 14(2) :16-24. 

57. The teeth of snails. Popular Sci., 34:187-188. 

58. Shell collecting near Rochester, New York. Nautilus, 14:69-71. 

59. Mollusks in grass. Op. cit., 14:93. 

1901 

60. The oyster and its relatiyes. Birds and Nature, 9:26-31. 

61. A reyision of the Limnaeas of northern Illinois. Trans. Acad. Sci. St. Louis, 

9(1): 1-24. 

62. Snails of the forest and field. Birds and Nature, 9:74-79. 

63. Snails of pond, riyer, and brook. Op. cit., 9:128-133. 

64. Snails of the ocean. Op. cit., 9:176-181. 

65. The Nautilus and other cephalopods. Op. cit., 9:222-227. 

66. New yarieties of fresh-water shells. Nautilus, 15(2):17-18. 

67. The digitations of the mantle in Physa. Bull. Chicago Acad. Sci., 2(4) :225-228. 

68. Description of a new species of Limnaea. Op. cit., 2(4) :229-230. 

69. The molluscan fauna of the Genessee Riyer. Amer. Nat., 35:659-664. 

70. The prong-horned antelope. Birds and Nature, 8:179-181. 

71. Limnaea auricularia in America. Nautilus, 15(5) :59. 

72. The educational yalue of natural history museums. Reyiew of Education, Chi- 

cago, 7:155-157. 

73. Some interesting molluscan monstrosities. Trans. Acad. Sci. St. Louis, 11:143-146. 



Chronological List of Publications xxvii 

1902 

74. Fhnwrbis bicariitatiis striaius, n. var. Nautilus, 15(10) :120. 

75. Editorial on museum articles. Review of Education, Chicago, 7:361. 

76. The Mollusca of the Chicago area. Part II. Gastropoda. Chicago Acad. Sci., 

Nat. Hist. Survey Bull.. 3(2) :131-410. 

77. Starfishes. Birds and Nature, 12:35-37. 

78. The cowries and shell money. Op. cii., 12:86-90. 

79. Some snails of the ocean. Op. cit., 12:134-139. 

80. The descriptive arrangement of museum collections. Museum Jour., (England), 

2:106-110. 

1903 

81. Shell collecting on the Mississippi. Nautilus, 16:102-105. 

82. Corals, sea-fans, and sea-whips. Birds and Nature, 13:83-85. 

83. The stonv corals. Op. cit., 13:131-133. 

84. Coral reefs. Op. cit., 13:179-181. 

85. The hydroid corals. Op. cit., 13:225-227. 

86. Shells of land and water. A familiar introduction to the study of the mollusks. 

A. W. Mumford and Co., Chicago, xvi + 175 pages. 

87. Pleistocene mollusks of White Pond, New Jersey. Nautilus, 17:38-39. 

88. A partial list of the marine mollusks of San Salvador. Bahamas. Op. cit., 17:57. 

89. Rib variation in Cardium. Amer. Nat., 37(439) :481-488. 

90. Sea urchins and sand dollars. Birds and Nature, 14:179-181. 

91. Notes on Murex marcoensis Sowerby. Nautilus, 17-88. 

1904 

92. The mollusks of Cedar Lake, Indiana. Op. cit., 17:112-113. 

93. Some American grasshoppers. Birds and Nature, 15:131-133. (Nom de plume, 

Collins Thurber) 

94. New varieties of American Limnaeas. Nautilus, 18:10-12. 

95. The molluscan fauna of the Dells of Wisconsin. Trans. Acad. Sci. St. Louis, 

14(2):99-105. 

96. Note on PUutorbis tnmcatus Miles. Op. cit., 14(2) :107-110. 

97. The arrangement of the collections of Mollusca in the Chicago Academy of 

Sciences. Museums Journal (England), 2 : 354-360. 

98. Spire variation in Pyramidula alternnta. Amer. Nat., 38(453) :661-668. 

99. New American Lynmaeas, II. Nautilus, 18:62-63. 

100. The bluebird. Birds and Nature, 16:158-161. (Nom de plume, Collins Thurber) 

101. The bald eagle. Op. cit., 16:232-236. (Nom de plume, Collins Thurber) 

1905 

102. The belted kingfisher. Op. cit.. 17:50-51. (Nom de plume, Collins Thurber) 

103. The flicker. Op. cit., 17:131-132. (Nom de plume, Collms Thurber) 

104. Critical notes on the smaller Lynmaeas. Nautilus. 18:125-127. 

105. The long-billed marsh wren. Birds and Nature, 17:179-180. (Nom de plume, 

Collins Thurber) 

106. New species of Lymrmea. Nautilus, 18:141-142. 

107. The marsh hawk. Birds and Nature, 17:201-202. (Nom de plume, Collins 

Thurber) 

108. The molluscan fauna of McGregor, Iowa. Trans. Acad. Sci. St. Louis, 15(3) : 

249-258. 

109. Notes on a collection of shells from Bass Lake, Indiana. Nautilus, 19:27-28. 

110. The museum and the public school. Museums Journal (England), 5:50-55. 

111. A new species of Lymnaea from Ohio, with notes on Lymnaea parva Lea. 

Nautilus, 19:51-53. 

112. The loggerhead shrike. Birds and Nature, 18:23-24. (Nom de plume, Collins 

Thurber) 

113. The hermit thrush. Op. cit., 18:50-51. (Nom de plume. Collins Thurber) 

114. Notes on the genitalia of Lymnaea. Amer. Nat., 39:665-679. 

115. The yellow-bellied sapsucker. Birds and Nature, 18:119-121. (Nom de plume, 

Collins Thurber) 

116. The cerulian warbler. Op. cit., 18:167-168. (Nom de plume, Collins Thurber) 

117. The American flamingo. Op. cit., 18:213-214. (Nora de plume, Collins Thurber) 



xxviii TJie Molluscan Family Plauorbidae 

1906 

118. The bob-white or quail. Op. cit., 19:23-24. (Nom de plume, Collins Thurber) 

119. The least bittern. Op. cit., 19:71-72. (Nom de plume, Collins Thurber) 

120. The blue-gray gnatcatcher. Op. cit., 19:110-111. (Xom de plume, Collins 

Thurber) 

121. A new variety of Planorbis nautileu.s Linn. Nautilus, 19:120. 

122. Lijmnaea hinklcyi n. sp. Op. cit., 19:142-143. 

123. Application of De Vries's mutation theory to the molluscs. Amer. Nat., 40: 

327-334. 

124. Notes on a collection of mollusks from the \-icinitv of Alpena, Michigan. Trans. 

Acad. Sci. St. Louis, 16(2):1-15. 

125. A new Sphaerium from Illinois. Nautilus, 20(2) :21. 

126. The dickcissel. Birds and Nature, 19:146-147. (Nom de plume, Collins Thurber) 

127. The great blue heron. Op. cit., 19:213-214. (Nom de plume, Collins Thurber) 

128. Lyninaea daniehi n. sp. Nautilus, 20:55. 

129. A catalogue of the Mollusca of Illinois. Bull. Illinois State Lab. Nat. Hist., 7(6): 

53-136. 

1907 

130. Descriptions of new species of Lyninaea. Nautilus, 20:125-127. 

131. The camera in science. Photo Era, 18:185-186. 

132. Two new species of Lymnaea. Nautilus, 21:52-55. 

133. Some observations on museum administration. Science, 26:666-669. 

1908 

134. Some instructive methods of bird installation. Proc. Amer. Mus. Assoc, 1:52-57. 

135. The Chicago Academy of Sciences. Science, 27:423-424. 

136. The Chicago Academy of Sciences: its past history and present collections. 

Chicago Acad. Sci., special publ., 2:1-7. 

137. Note on Lymnaea desidiosa Say. Nautilus, 22:20-23. 

138. Suggestions for a natural classification of the familv Lvmnaeidae. Science, 27: 

942-943. 

139. The Chicago Academy of Sciences. Op. cit., 28:138-140. 

140. A new American Planorbis. Nautilus, 22:45. 

141. A small collection of shells from Texas. Science, 28:534-535. 

142. Provincial museums. Op. cit., 28:684-685. 

143. The relation of the State Academy of Science to the Natural History Sur\'ey of 

the Chicago Academy of Sciences. Trans. Illinois State Acad. Sci., 1:68-69. 

144. The Natural History Survey of the Chicago Academy of Sciences. Proc. Amer. 

Assoc. Mus., 2:15-19. 

1909 

145. Annual report of the Chicago Academy of Sciences. For the j'^ear 1908. Bull. 

Chicago Acad. Sci., 3:1-21. 

146. A new species of Lymnaea. Nautilus, 22:140-141. 

147. Description of a new fossil Lymnaea. Op. cit., 23:19-21. 

148. Note on Planorbis binneyi Tryon. Op. cit., 23:41-42. 

149. The Chicago Academy of Sciences: Its past history and present collections. 

Museums Jour. (England), 8:423-428. 

150. Range of Lymnaea umbiJicata. Nautilus, 23:80 

151. Rei)ort on the educational work of some east American museums. Bull. Chicago 

Acad. Sci., 3:26-34. 

152. Mollusks from Kansas and Oklahoma. Nautilus. 23:91-94. 

153. Suggestions for an educational exhibit of mollusks. Proc. Amer. Assoc. Mus., 

3:56-59. 

154. Exhibition cases without shelves. Op. cit., 3:128-130. 

1910 

155. A new variety of Lymnaea stagnalis. Nautilus, 23:112-113; 125-126. 

156. Note on free public museums. Science, 31:221. 

157. Annual report of the curator. Bull. Chicago Acad. Sci., 3:26-45. 

158. Annual report of the librarian. Op. cit., 3:45-46. 

159. The ecology of the Skokie Marsh area, with special reference to the Mollusca. 

Bull. Illinois State Lab. Nat. Hist., 8:437-499. 

160. Preliminary note on the life of Glacial Lake Chicago. Science, 31:715-717. 



Chronological List of Publications 



XXIX 



161. Suggestions for an cducutiomil exhibit of niollusks. Muscvniis Jour. (England), 

9:394-397. 

162. The ecology of the Skokie Marsh area with sjiecial reference to the moUusks. 

Trans. Illinois State Acad. Sci., 3:106-108. 

163. Description of a new Lymnaea. Nautilus, 24:58-60. 

164. Mollusks of Unionville, Connecticut. Op. cit., 24:68-69. 

1911 

165. The Lymnaeidae of North and Middle America, recent and fossil. Chicago 

Acad. Sci., Special Publ., 3:xyi + 539. 

166. Annual report of the curator. Bull. Chicago Acad. Sci., 3:137-150. 

167. Annual report of the librarian. Op. cit., 3:151-152. 

168. A method of exhibiting large descriptiye labels on the outside of museum cases. 

Proc. Amer. Assoc. Mus., 4:21-23. 

169. School loan collections as prepared by the Chicago Academy of Sciences. Op. cit., 

4:36-40. 

170. Mollusks of Wellesley Island and yicinity, St. Lawrence Riyer. Nautilus, 25:66-67. 

171. The molluscan fauna of Tomahawk Lake, Wisconsin. Trans. Wisconsin Acad. Sci., 

Arts, and Lett., 17(1) :200-246. 

1912 

172. A new Flauorbis from Michigan. Nautilus, 25:118-120. 

173. Post-glacial life of Wilmette Bay, Glacial Lake Chicago. Trans. Illinois State 

Acad. Sci., 5:108-116. 

174. A method of exhibiting insect collections. Proc. Amer. Assoc. Mus., 6:108-111. 

175. Recent additions to the catalog of Illinois Mollusca. Trans. Illinois State Acad. 

Sci., 5:143-145. 

1913 

176. A new Lymnaea from Montana. Nautilus, 26:115-116. 

177. Pseudogalba, new name for Si))ipsonia. Op. cit.. 26:120. 

178. Interglacial records in New York. Science, 36:523-524. 

179. Notes on post-glacial Mollu.sca. I. Emmet County, Michigan. Nautilus, 27:7-8. 

180. Galba jerruginea in Oregon. Op. cit., 27:24. 

181. Mollusca of Wyoming County, New York. Op. cit., 27:54. 

182. Notes on post-glacial Mollusca. II. Waukesha County, Wisconsin. Op. c;/., 27:68. 

183. Interglacial mollusks from South Dakota. Science, 38:858-859. 

1914 

184. Northern Idaho shells. Nautilus, 27:104-106. 

185. Mollusks from Magician Lake, Cass and Van Buren Counties, Michigan. Op. cit., 

28:8-10. 

186. L"se of enlarged photographs in museum groups. Proc. Amer. Assoc. Mus 

89-91. 

187. An eyening with the aquarium and snailery. Nature Study Rey., 10:315-320 

1915 

188. On the classification of the Lymnaeidae. Nautilus, 29:20-24. 

189. Campeloma leunsii Walker in Illinois. Op. cit., 29:36. 

190. Mollusks from Berrien County, Michigan. Op. cit., 29:47. 

191. Pleistocene mollusks from Illinois. Op. cit., 29:87-88. 

1916 

192. A mollusk injurious to garden yegetables. Science, 43:136. 

193. The fresh-water Mollusca of Oneida Lake, New York. Nautilus, 30:5-9. 

194. North American faunal areas. Science, 44:273-275. 

195. The relation of mollusks to fish in (Dneida Lake. New York State Coll. For., 

Technical Publ., 4:1-366. 

196. The auroral display of August 26. Science, 44:568. 

197. A new yariety of Lamp.dli.s from Oneida Lake with notes on the luteola group. 

Nautilus, 30:74-77. 

198. Further notes on the po.st-glacial biota of Glacial Lake Chicago. Trans. Illinois 

State Acad. Sci., 7:74-78. 

199. The relation of the Mollu.sks of Oneida Lake to the basin of lower South Bay. 

(Abstract). Ecol. Soc. Amer., 1916. 




XXX The Molluscan Family Planorbidae 

1917 

200. Notes on Acella haldemani (Desh.) Binney. Nautilus, 20:135-138. 

1918 

201. Further notes on the Mollusca of Oneida Lake, New York; the molhisks of 

lower South Bay. Op. cit., 31:81-93. 

202. A moHuscan garden pest. Science, 47:391-392. 

203. The animal world in a handful of algae. The Guide to Nature, 10:376-380. 

204. Notes on nidification in Gillia and Amnicola. Nautilus, 32:19-23. 

205. Description of a new variety of fresh-water mussel from Oneida Lake, New York. 

Appendix to New York State Coll. For.. Technical Publ., 9:247-248. 

206. The productivity of invertebrate fish food on the bottom of the Oneida Lake, 

with special reference to mollusks. Op. cit., 9:1-264. 

207. Post-glacial Mollusca from the marls of Central Illinois. Jour. Geol., 26(7) : 

659-671. 

208. The relation of shellfish to fish in Oneida Lake, New York. New York State 

Coll. For., Circular, 21:1-34. 

1919 

209. Description of a new species and variety of Planorbis from post-glacial deposits. 

Nautilus, 32(3) : 94-97. 

210. Mollusks infested with parasitic worms. Op. cit., 32(3) :97-98. 

211. The ecology of North American Lymnaeidae. Science, 49:519-521. 

212. A new species of Physa from New. York State. Nautilus, 33:11-13. 

213. Studies in aquiculture or fresh-water farming. Nat. Hist., 19:478-488. 

214. Molluska of the Crocker-Land Expedition to northwest Greenland and Grinnell 

Land. Bull. Amer. Mus. Nat. Hist., 41(11) :479-517. 

215. Fresh-water Mollusca from Colorado and Alberta. Op. cit., 41(13) :527-539. 

216. The Museum of Natural Historv of the University of Illinois. Trans. Illinois 

State Acad. Sci., 12:57-63. 

1920 

217. Animal life and sewage in the Genessee River, New York. Amer. Nat., 54:152-161. 

218. A new Planorbi.^ from Illinois. Nautilus, 33:123-125. 

219. A new form of Amnicola from the Ohio Pleistocene deposits, with notes on a 

Physa from the same formation. Op. cit., 33:125-127. 

220. Physa smithiana, new name for Phy.sa smithii. Op. cit., 33:142. 

221. The life of the Pleistocene or glacial period, as recorded in the deposits laid 

down by the great ice sheets. Univ. Illinois Bull., 17(41) : iv -f- 476 pages. 
Urbana, Illinois. 

222. Pleistocene Mollusca from Indiana and Ohio. Jour. Geol., 28(5) :439-457. 

223. Animal life in loess deposits near Alton, Illinois, with descriptions of two new 

varieties of land shells from the same deposits. Nautilus, 34:61-66. 

224. Notes on a small collection of shells from Alaska. Op. cit., 34:67-68. 

225. The Museum of Natural History. In 'Sixteen Years at the University of Illinois,' 

a statistical study of the administration of President Edmund J. James. Uni- 
versity of Illinois, Urbana, pages 119-121. 

226. A mussel survey of the ujijier waters of the \'ermilion River with special refer- 

ence to the Salt Fork. (With Frank Smith). Trans. Illinois State Acad. Sci., 
12:129-131. 

227. Effect of sewage and other pollution on animal life of rivers and streams. Op. cit., 

13:271-279. 

1921 

228. The value of ecology in the interpretation of fossil faunas. School Sci. and Math., 

21:323-327. 

229. Baker's 'Life of the Pleistocene' (reply to criticism by Dr. Shufeldt). The Auk, 

38:155-156. 

230. Preparing collections of the Mollusca for exhibition and study. Trans. Amer. 

Micros. Soc, 40(l):31-46. 

231. New forms of Pleistocene mollusks from Illinois. Nautilus, 35:22-24. 

232. The importance of ecologv in the interpretation of fossil faunas. Ecology, 2: 

277-280. 



Chronological List of Publications xxxi 

1922 

233. Pleistocene Molluska from northwestern and central Illinois. Jour. GeoL, 30(1): 

43-62. 

234. Fluke infections and the destruction of the invertebrate host. Jour. Parasitol., 

8:145-147. 

235. New species and varieties of Mollusca from Lake Winnebago, Wisconsin, with 

new records for this state. Nautilus, 35:130-133; 36:19-21. 

236. New Lymnaeas from Wisconsin and Minnesota, with notes on shells from the 

latter state. Op. cit., 36:22-25. 

237. The molluscan faima of the Big Vermilion River, Illinois, with special reference 

to its modification as the result of pollution by sewage and manufacturing 
wastes. Illinois Biol. Monogr., 7(2):1-127. 

238. The museum, the original exponent of visual education. School Sci. and Math., 

22:651-655. 

1923 

239. The Pleistocene Mollusca from the vicinity of Joliet, Illinois. Trans. Illinois 

State Acad. Sci., 15:408-420. 

240. A new Anodontoidcs from Wisconsin. Nautilus, 36:123-125. 

241. Description of a new Lymiiaea from Yellowstone Park. Op. cit., 36:125-126. 

242. The educational value of a university natural history museum. Science, 58: 

55-57. 

243. Some problems of a university curator. Museum Work, 5:92-94. 

244. The use of molluscan shells bv the Cahokia mound builders. Trans. Illinois State 

Acad. Sci., 16:328-334. 

245. A new Physa from California. Nautilus, 38:15. 

246. Report of curator, the Museum of Natural History. In 'President's Report,' 

University of Illinois, 1922-1923:159-162. 

1924 

247. The place of the museum in university instruction. Museum Work, 7:81-87. (Re- 

printed in School Life, 10:33-35). 

248. The fauna of the Lake Winnebago region. A quantitative and qualitative survey 

with special reference to the Mollusca. Trans. Wisconsin Acad. Sci., Arts, 
and Lett., 21:109-146. 

1925 

249. Report of curator. Museum of Natural Historv. In 'President's Report,' Uni- 

versity of Illinois, 1924-1925:117-119. 

1926 

250. Museums and nature. Naturalist's Guide to the Americas, 27-29. 

251. The effects of pollution on animal life. Op. cit., 38-41. 

252. Nomenclatorial notes on American fresh-water Mollusca. Trans. Wisconsin Acad. 

Sci., Arts, and Lett., 22:192-205. 

253. Bowmanville low water stage of Glacial Lake Chicago. Science, 64:249. 

254. Fresh-water Mollusca from White Lake, Oakland County, Michigan. Nautilus, 

40:49-52. 

255. New forms of Planorbis and Lymnaca with notes on other forms. Op. cit., 41: 

23-24. 

256. Report of curator. Museum of Natural Historv. In 'President's Report,' Uni- 

versity of Illinois, 1925-1926:145-149. 

1927 

257. Description of a new species of Lymnaea from British Columbia. Nautilus, 41 : 

23-24. 

258. Description of a new species of Somatogyrus from Wisconsin. (With H. A. 

Pilsbry). Op. cit., 41:24-26. 

259. The naiad fauna of the Rock River Svstem; a studv of the law of stream dis- 

tribution. Trans. Ilhnois State Acad. Sci., 19:103-112. 

260. New varieties of Stagnicola from Wisconsin and Wyoming. Nautilus, 40(3) : 85-87. 

261. New varieties of Helisoma antrosa from Wisconsin and Minnesota. Op. cit., 40: 

82-85. 



xxxii The Molluscan Family Planorbidae 

262. On the division of the Sphaeriidae into two subfamilies; and the description of 

a new species and genus of Unionidae, with descriptions of new varieties. 
Amer. Midi. Nat., 10(7) :220-223. 

263. Descriptions of new forms of Pleistocene land mollusks from Illinois, with remarks 

on other species. Nautilus, 40:114-120. 

264. Molluscan associations of White Lake, Michigan ; a study of a small inland lake 

from an ecological and systematic viewpoint. Ecology, 8(3) : 353-370. 

265. A new variety of Helisoma campanulata from Michigan. Nautilus, 41:49-51. 

266. Report of curator, Museum of Natural Historv. In 'President's Report,' Uni- 

versity of Illinois, 1926-1927:129-132. 

1928 

267. Descriptions of new varieties of land and fresh-water mollusks from Pleistocene 

deposits in Illinois. Nautilus, 41:132-137. 

268. The American Bythinia not whollv an introduced species. Trans. Illinois State 

Acad, of Sci., 20:56-63. 

269. Molluscan life of the loess deposits of Illinois. Op. cit., 20:269-292. 

270. Influence of a changed en\-ironment in the formation of new species and varieties. 

Ecology, 9:271-283. 

271. The fresh-water Mollusca of Wisconsin. Part I. Gastropoda. Wisconsin Acad. 

Sci., Arts, and Lett., 1928 :i-xx -f 507 pages. 

272. The fresh-water Mollusca of Wisconsin. Part II. Pelecypoda. Bull. Univ. Wis- 

consin, 1527: vi + 495 pages. 

273. The Mollusca of Chautauqua Lake, New York, with descriptions of a new variety 

of Ptychohranchus and of Helkoma. Nautilus, 42:48-60. 

274. Report of curator. Museum of Natural History. In 'President's Report,' Uni- 

versity of Illinois, 1927-1928:124-127. 

1929 

275. Fossaria perplexa F. C. Baker and Junius Henderson. Nautilus, 42:103-104. 

276. Certain anatomical features of the fresh-water mollusc, Helisoma corpulenta Say. 

Trans. Amer. Micros. Soc, 48(1) :44-47. 

277. Vermont shells. Nautilus, 41:108. 

278. Mollusca from Vermilion and Pelican Lakes, Minnesota, with the description of a 

new variety of Helisoma corpulenta. Op. cit., 42:95-97; 131-136. 

279. A study of the Pleistocene Mollusca collected in 1927 from deposits in Fulton 

County, Illinois. Trans. Illinois State Acad. Sci., 21 :288-312. 

280. The use of molluscan shells by the Cahokia mound builders. The Cahokia 

Mounds, Bull. Univ. Illinois, 26(4) : 147-154. 

281. Stagnicola couleensis F. C. Baker. In Henderson, 'Some Fresh-water Mollusca 

from Washington and Oregon,' Nautilus, 41:118-120. 

282. The European starling in Illinois. Science, 69:521-522. 

283. Report of curator. Museum of Natural History. In 'President's Report,' Univer- 

sity of Illinois, 1928-1929:140-146. 

1930 

284. A new record of Castoroicles ohioensis from Illinois. Science, 71:389. 

285. On genus and species making. Op. cit., 72:37-39. 

285a. University museum exhibition cases. Museum News, 7(19):11-12. 

286. The use of animal life bv the mound-building Indians of Illinois. Trans. Illinois 

State Acad. Sci., 22:41-64. 

287. The molluscan fauna of the southern part of Lake Michigan and its relationship 

to old Glacial Lake Chicago. Op. cit., 22:186-194. 

288. A review of our present knowledge concerning the character and distribution of 

the Pleistocene aquatic molluscan life of Illinois. Op. cit., 22:411-434. 

289. Influence of the glacial period in changing the character of the molluscan fauna 

of North America. Ecology, 11(3) :469-480. 

290. The variation of molluscan life during the Pleistocene and recent time. Nautilus, 

44(l):21-24. 

291. Notes on Professor Shimek's paper on land snails as indicators of Ecological 

conditions. Ecology, 11(4) : 788-789. 

292. Report of curator. Museum of Natural History. In 'President's Report,' Univer- 

sity of Illinois, 1929-1930:164-169. 



Chronological List of Publications xxxiii 

1931 

293. Description of a new variety of Valvata Icwidi Cm-rier. Nautilus, 44(4) :119-121. 

294. Additional notes on animal life associated with the mound builders of Illinois. 

Trans. Illinois Acad. Sci., 33:231-235. 

295. A re-studv of the interglacial moUuscan fauna of Toronto, Canada. Op. cit., 33: 

358-366. 

296. Ecological relationship of the genus Pomatiop.iin with special reference to Pomon 

tioits/s Inpidaria. Ecology, 12(3) :389-396. 

297. The classification of the large planorboid snails of Europe and America. Proc. 

Zool. Soc. London, 1931 (2):575-592. 

298. Fresh-water Mollusca from central Ontario. (With A. R. Cahn). Ann. Rept., 1929, 

Natl. Mus. Canada, pp. 41-64. 

299. Pulmonate Mollusca peculiar to the Pleistocene period, particularly the loess 

deposits. Jour. Paleontol., 5(3) :270-292. 

300. Plei.stocene historv of the terrestrial Mollusca of Fulton Countv, Illinois. Trans. 

Illinois State Acad. Sci., 24(2) : 149-155. 

1932 

301. Stognicola apicina and Stagnicola walkeriann. Nautilus, 45:139-140. 

302. Molluscan shells from Etowah Mounds. Chapter V, in W. K. Moorehead's 'Ex- 

ploration of the Etowah Site in Georgia.' Department of Archeology, Phillips 
Academy, Andover, Massachusetts, pp. 145-149. 

303. The ecology of Say's Limnaeus elodes. Ecology, 13:286-289. 

304. New species and varieties of Helisoma and Gyraulus from Canada. Nautilus, 

46(1) :6-9. 

305. A new race of Pohjgyra apprcssa from Illinois. Op. cit., 46(2) :48-49. 

1933 

306. Pohjgijru dorfcuilliann and Bulhuoides dcalbatus in Illinois. Op. cit., 47:4-7. 

307. A new Stagnicola from Montana. (With Junius Henderson). Op. cit., 47:30-32. 

308. Self fertilization and nidification in Physa halei. Op. cit., 47:35. 

309. Studies on the bottom fauna of fresh-water lakes. Science, 78:190-191. 

310. The genitalia of the Indian mollusk, Indoplanorbis exustus. Jour. Morphol., 

55(1):1-13. 

311. A new form of Polygyra tridentnta from Illinois. Nautilus, 47(2) :59. 

312. New species of Lvmnaeidae from British America. Jour. Washington Acad. Sci., 

23(11) :520-523." 

1934 

313. Description of a new species of Gyraulus. Canadian Field-Nat., 48-27. 

314. The variation and distribution, recent and fossil, of the snail Polygyra profunda, 

in Illinois. Amer. Midi. Nat., 15(2) : 178-186. 

315. The variation and distribution, recent and fossil, of the snail Polygyra profunda, 

in Illinois. (Abstract). Trans. Illinois State Acad. Sci., 25:189. 

316. New Canadian Lymnaeas. Canadian Field-Nat., 48:69-70. 

317. Two new races and a new species of Helisoma from California. Nautilus, 47: 

140-142. 

318. The molluscan fauna of the great river valleys of Illinois. Trans. Illinois State 

Acad. Sci., 26:129. 

319. New Lymnaeidae from the United States and Canada: 1. California, Oregon, 

and other western states. Nautilus, 48(l):17-20. 

320. A new mammoth record for Illinois. Science (n.s.), 80:118. 

321. A new species of Gyraulus from Canada. Canadian Field-Nat., 48:135. 

1935 

322. Mollusca from Turkey Run State Park. Indiana. Nautilus. 48(3) : 105-106. 

323. Land and fresh-water molluscs from North Star Lake and vicinitv, Itasca County, 

Minnesota. Amer. Midi. Nat., 16(3) :257-272. 

324. Stratiographic sequence of mollu.scan fo.ssils in loess deposits. (Abstract). Proc. 

^ Geol. Soc. Amer. for 1934:372-373. 

325. New species and races of Lvmnaeidae from Newfoundland. (With Stanlev T. 

Brooks). Nautilus. 49:10-13. 

326. The generic po.sition of Planorbi.<> iimhilicatellu^ with the description of a new 

group of Planorbidae. Op. cit., 49(2) :46-48. 

327. Stagnicola elrodiana, new name for Limnaea montana Elrod. Op. cit., 49:60. 



xxxiv The Molluscan Family Plauorbidae 

1936 

328. The generic position of Plonorbis obstructus Morelet. Op. cit., 49(3) ".104. 

329. Quantitative examination of molluscan fossils in two sections of Pleistocene loess 

in Illinois. Jour. Paleontol.. 10(l):72-76. 

330. The fresh-water mollusc Hclisuma corpulentum and its relatives in Canada. Natl. 

Mus. Canada Bull., 79:1-37. 

331. Paleontology. In A. L. Lugn's 'The Pleistocene Geology of Nebraska.' Nebraska 

Geol. Surv. Bull., 10:1-223. (Identifications and comments on pages 122, 123, 
183-187, 190, 194, 195, 210-212). 

332. New Lvmnaeidae from the United States and Canada, II. Michigan, Minnesota, 

and Montana. Nautilus, 49(4) : 127-140. 

333. The relationship of Parapholyx. Op. Cit., 50:30-31. 

334. Remains of animal life from the Kingston kitchen midden site near Peoria, Illi- 

nois. Trans. Illinois State Acad. Sci., 29:243-246. 

1937 

335. Identification of shells. In Cole and Deuel, 'Rediscovering Illinois.' Appendix 

VI, 'Explorations in and around Fulton County,' pages 269-270. 

336. Mollu.sca from the Prince Albert National Park, Saskatchewan. Nautilus, 50(4) : 

113-117. 

337. An Illinois record for the little brown crane. The Auk. 54:388. 

338. A new Pleistocene race of Polygyra apprcssa. Nautilus, 51(l):22-23. 

339. Pleistocene land and fresh-water Mollusca as indicators of time and ecological 

conditions. In 'Symposium on Early Man,' held at Academy of Natural Sci- 
ences, Philadelphia, March, 1937. J.B. Lippincott, 1937:67-74. 

340. Abundance of the European starling in Illinois. Science, 85:564. 

1938 

341. New land and fresh-water Mollusca from the Ui^per Pliocene of Kansas and a 

new species of Gyraulus from Early Pleistocene strata. Nautilus, 51(4) : 126-131. 

342. The Mollusca of the shell heaps or escargotieres of northern Africa. Part III of 

'Prehistoric habitation sites in the Sahara and North Africa.' Logan Mus. 
Bull., 5:185-225. 

1939 

343. Original copies of Say's 'American conchology.' Nautilus, 52:106. 

344. Stagidcola bulimoides vancouverensis nov. var. Op. cit., 52:144. 

345. Remains of animal life from the Kingston kitchen midden site near Peoria, Illi- 

nois. 'The Kingston Site,' by A. M. Simpson. Peoria Acad. Sci., 1939:13-15. 

346. Land and fresh-water Mollusca from western Ontario. Canadian Jour. Research, 

D, 17:87-102. 

347. Fieldbook of Illinois land snails. Illinois Nat. Hist. Surv., Manual 2, 166 pages. 

1940 

348. South American species referred to Planorbula. Nautilus, 53:106. 

349. The case of Linmacu.'< sordidus Ku.ster. Op. cit., 53:138-141. 

350. A new HcIiso)na from the Pliocene of Florida. Op. cit., 54:17. 

351. A new anatomical classification of the Planorbidae. Tenth Ann. Rept. Amer. 

Malacol. Union, Philadelphia, 1940:4-5. 

1941 

352. A new species of Drcpanotrema and some preoccupied planorboid names. Nau- 

tilus, 54:96-97. 

353. A new race of Parapholyx effusa. Op. cit., 55:16-17. 

354. A study in ethnology of the prehistoric Indians of Illinois. Part II. Contributions 

to the archaeologv of the Illinois River vallev. Trans. Amer. Philos. Soc. 
(n.s.), 32(l):51-67. 

1942 

355. Lymnaea .'itagnalis and Lymnnca (Radix) nuricularia. Nautilus, 55:105-106. 

356. Land and fresh-water Mollusca of New Hampshire. Amer. Midi. Nat., 27:74-85. 



Chronological List of Publications xxxv 

357. Collect inji and preserving fresh-water snails. Ann. Rei)t. Amcr. Malacol. Union, 

Philadelphia, 1941:5-9. 

358. A new Gi/raulii.^ from the Pleistocene of California and a new Parapholyx from 

a supposed Pliocene deposit in Oregon. Nautilus, 55:130-132. 

1943 

359. Mollusca contained in the test pit deposits. Carnegie Inst, of Washington, Publ. 

538:117-119. 

1945 

360. The Molluscan Family Planorbidae. The University of Illinois Press, Urbana. 



BIOGRAPHICAL CONTRIBUTIONS 

(In Dictionary oj American Biography) 

1929. Augustus Addison Gould. 1932. George Washington Tryon. 

1930. Robert Kennicott. 1933. Victor Sterki. 
1932. William Stimpson. 



BOOK NOTICES AND REVIEWS 

(In Ecology) 

1921 

The fresh-water Mollusca of the Parish of Aldenham, by A. E. Boycott. 2:230. 
Correlation of shape and station in fresh-water mussels, by A. E. Ortmann. 2:231. 
Natural historv and propagation of fresh-water mussels, by Shira, Coker, Clark, and 
Howard. 2:314. 

1922 
The Mollusca collected by the University of Michigan-Walker expedition in southern 

Vera Cruz, Mexico, by H. B. Baker." 3:342. 
Final report on the study and appraisal of mussel resources in selected areas of the 

upper Missi-ssippi River, by N. M. Grier. 3:343. 
The edible clams, mussels, and scallops of California, bv F. W. Wevmouth. 3:344-345. 
Mollusca of North Dakota, by Mina L. Winslow. 3:345. 
Stream pollution. A re^"iew of 'Stream pollution studies,' bv Russel Suter and Em- 

meline Moore. 3:340-341. 

1923 

On the effect of salinity on Teredo navalis, bv H. F. Blum. 3:318. 
The Mollusca of Dickinson County, by H. B. Baker. 4:318. 
The Champlain Sea, bv Winifred Golding. 4:318. 
The Mollusca of Oundle, by Rev. C. E. Y. Kendall. 4:319. 
Variations in the shell of Teredo navalis, by R. C. Miller. 4:319. 

1924 

The Kentucky River and its mussel resources, by E. Danglade. 4:431. 

Studies of the biologv of fresh-water mussels. III. Distribution and movements of 
Winona Lake mussels, by W. R. Allen. 5:220. 

The Mollusca collected bv the Universitv of Michigan-Williamson expedition in 
Venezuela, by H. B. Baker. 5:221. 

Biology and economic value of the sea mussel, Mytilu.'^ rdulii^, by I. A. Field. 5:306. 

Mollu.^ca of the southwestern states. XI. From the Tucson Range to Ajo, and moun- 
tain ranges between the San Pedro and Santa Cruz riv(>rs, Arizona, bv H. A. Pils- 
bry and J. H. Feniss. 5:222. 



xxxvi The MoUuscan Family Planorhidae 

The small bottom and shore fauna of the middle and lower Illinois River and its con- 
necting lakes, Chillicothe to Grafton: Its valuation, its resources of food supply, 
and its relation to the fishery, by R. E. Richardson. 5:416-418. 

1925 

Land and fresh-water Mollusca of the Dutch Leeward Islands, by H. B. Baker. 6:193. 
Conditions imder which Goniobasis livescene occurs in the island region of Lake Erie, 
by F. H. Krecker. 6:320. 

1926 

Changes in the small bottom fauna of Peoria Lake, 1920 and 1922, bv R. E. Richard- 
son. 7:229-230. 
Illinois River bottom fauna in 1923. by R. E. Richardson. 7:230. 



THE MOLLUSCAN FAMILY PLANORBIDAE 

PART I 
CLASSIFICATION AND GENERAL MORPHOLOGY 



I. 

GENERAL MORPHOLOGY 

A. EXTERNAL APPEARANCE OF THE ANIMAL 

CONTRARY TO GENERAL CUSTOM, the characteristics of the 
animal and its gross anatomy will be considered before taking up 
the shell and its variations. This procedure seems more logical 
since it is the animal which secretes and builds up the shell or calcareous 
covering (see plate 70, fig. 1). 

The head and foot protrude from the shell and bear several important 
organs. The foot is long and variably narrow, broadly rounded in front, 
and usually tapering to a point behind. There is a large velar area above 
and in front of the foot which is retained from the embryonic animal, as in 
Lyinnaca, and bears the head, eyes, and tentacles. This velum is broad and 
short and is capable of great extension and retraction; it is usually some- 
what semicircular in shape. 

The tentacles are very long and filiform, varying from one-half to the 
whole length of the foot, and are placed at about the junction of the velum 
with the foot. The eyes are placed on swellings at the inner base of the 
tentacles. The mantle collar does not extend beyond the edge of the aper- 
ture of the shell. The texture of the foot is smooth, not granular as in 
some of the land snails, and there are no grooves on the body, the animals 
resembling the Lymnaeas in this respect. 

The Planorbidae differ from the related family Lymnaeidae in having 
certain of the organs on the left side (sinistral), the organs in Lymnaeidae 
being on the right side (dextral). In this respect the Planorbidae resemble 
the families Physidae and Bulinidae. The tentacles of the Planorbidae, 
Physidae, and Bulinidae are also similar and differ from the Lymnaeidae 
and Ancylidae, in which the tentacles are flattened and triangular. 

The breathing organ of the Planorbidae, a modified lung as in the family 
Lymnaeidae, is supplemented by a prolongation of the anal region (auri- 
form lobe), called the pseudobranch or false gill, which may take over the 
function of breathing when the animal is submerged and can not obtain 
free air. This organ is highly vascular, many blood vessels entering it from 
the lower part of the lung cavity. It is comparatively a recent organ, 
being post-natal in origin, not having been observed in embryological 
development. 

The pseudobranch varies greatly in shape, being long and narrow, wide, 
leaf-like, or rounded in different genera. It always bears a portion of the 
rectum and the anus opens at the upper right side. There is usually a ridge, 
more or less heavy and distinct, which begins on the upper part of 
the rectum and ends in the middle or at the base of the pseudobranch. The 
variations of the pseudobranch are shown on the plates illustrating the anat- 
omy of each genus. A siphon-like extension of the mantle, called the 
pncumostome or respiratory opening, which may be greatly expanded, 
jirovides a tube-like conduit for free air to reach the lung. The jiseudo- 
branch is on the left side of the body and the pneumostome is to the right 
of this organ nearer the median line of the neck. 



4 The Molluscan Family Planorbidae 

The genital outlets are on the left side of the neck, the male opening 
just behind the left tentacle and the female opening a short distance behind 
the male opening in the side of the neck. In many individuals the penial 
complex has been observed protruding from the male opening (plate 29, 
figs. 6, 7, 11, 12), the animal having been killed while in breeding con- 
dition. That self-impregnation of the female system by sperm from the 
extended penial complex is possible is easily believed when the closeness of 
the two sex outlets is observed. 

The body above the foot may be flatly rounded or it may be rounded 
above and flattened on both sides of the foot (plate 70, fig. 10). Good 
figures of the animal of Tropicorbis are shown on plate 78. 

The color of the animal differs in the various genera. Mostly it is 
bluish-slate or blackish, grayish, or brownish, the color being lighter on the 
base of the foot and on the tentacles. In some species the color is yellow- 
ish. There are often flecks or spots of white on the foot and tentacles. The 
mantle, especially over the lung and kidney, is in many groups heavily 
blotched with black or brown. 

The shell may be carried perpendicularly, as in Helisoma (plate 70, 
fig. 7) , or it may lean to the left sicle, causing the shell to be pseuclodextral 
or ultradextral, as in Gyraulus and JMenetus (plate 70, fig. 9). 



B. GENERAL INTERNAL ANATOMY 

The internal anatomy includes the following systems: Reproductive, Di- 
gestive, Respiratory, Renal, Circulatory, INIuscular, and Nervous. The most 
important internal structure for classification purposes is the reproductive 
system and this will be first considered. 

[a] The Reproductive System 

Like other Basommatophora, the Planorbidae are hermaphroditic with the 
organs of the two sexes mostly separated. The difi^erent organs may be 
tabulated as follows: 

' vergic sac 
verge 
sperm canal 

Female organs <{ nidamental gland diaphragm or 

muscular ring 
preputium 
penial gland 
penial gland duct 
pilasters 
^ muscles 

f ovotestis 
] ovisperm duct or 
] hermaphrodite 
1^ duct 

Male Organs. External form. In the natural position the penial complex 
lies over the vagina and uterus (plate 39, fig. 3). When pulled away from 
this position its form is seen to be more or less cylindrical and to consist 
of a large bulbous lower portion, preputium (PR) and a smaller pyriform 
portion, the vergic sac (VS, plate 24, fig. 11). A narrow tube, the vas 
deferens (VD) is inserted at the summit of the vergic sac. This descends to 



Male organs. 



vagma 
uterus 
oviduct 

nidamental gland 
spermatheca 
spermathecal duct 
, albumen gland 

' penial complex 

vas deferens 

prostate 

prostate duct 
, seminal vesicle 



Penial complex. 



Common to both 
male and female. 



General Morphology 5 

near the male openinti; wlicre it is concealed in the muscular tissue of the 
neck of the animal and appears again near the female opening (plate 24, 
fig. 15 1. In some species the vas deferens is enlarged as it enters the vergic 
sac, the enlargement being similar to the epipliallus of the land snails 
(plate 39, fig. 7, Mcnetus). 

In one group of species (the Helisomatinae) there is usually a duct 
(pcnial gland duct, plate 24, fig. 11, DC) which normally lies coiled at a 
point between the vergic sac and the preputium (plate 27, fig. 9, DCO). 
This may be very long, as in HelUoma trivolvu (i:)late 24, fig. 11) or short, 
as in Hclisoma anceps (plate 23, fig. 3, DC). In another subfamily (Planor- 
binae) there is no ])enial gland duct except in two or three genera. 

There are one or two retractor muscles of the penial complex (plate 24, 
fig. 11, RM; plate 39, fig. 9, RM; plate 34, fig. 2) and a number of muscles 
believed to be supporting muscles to retain the penial complex in position. 
The retractor muscles enter the columellar muscle but the supporting 
muscles are attached to the muscular wall of the forepart of the body. 
The supporting muscles may in a measure perform the office of additional 
retractor muscles in some genera, especially in helping to retract the pre- 
l)utium after eversion. There do not appear to be any protractor muscles; 
the penial complex becomes turgid by blood pressure. 

The penial complex assumes many shapes in the genera belonging to 
the subfamily Helisomatinae. The preputium may be pushed upward and 
the vergic sac may occupy a position on the side of the prei)utium as in 
Helisoma campamdatum (plate 27, figs. 5-8). 

The vas deferens is continued near the female complex and borders 
the uterus and oviduct where it is a small tube (plate 24, fig. 15, Helisoma 
trivolvis). Just above the spermatheca the prostate appears. This organ 
varies greatly in the different genera. In Helisoma (plate 24, fig. 15, PRS) 
it is somewhat elongated and fan-shaped and the compound diverticula 
empty directly into the sperm duct along a very small portion of that 
tube. A cross section of the prostate in Helisoma trivolvis illustrates this 
condition (plate 24, fig. 13; see also plate 27, figs. 4 and 12, cross sections 
of Hclisoma ca)npamdatum) . The section is seen to be distinctly fan- 
shaped. In some other genera the prostate duct is separated from the sperm 
duct and vas deferens and the prostate is greatly lengthened. The prostate 
is composed of many or few diverticula arranged in a single series, each 
diverticulum being attached to and emptying into the separate prostate 
duct, which in turn empties into the vas deferens below the prostate 
(plate 14, figs. 7, 9; plate 1, figs. 1, 7). 

Bevond the prostate the vas deferens is continued as a somewhat larger 
tube, the sperm duct (plate 27, fig. 14, SPD; plate 24, fig. 15). At its distal 
end the sperm duct unites with the oviduct to form the ovisperm duct or 
hermaphrodite duct (plate 27, fig. 14; plate 34, fig. 6). 

About midway of the ovisperm duct is a glandular enlargement which 
has been called the seminal vesicle (SV). Many students of both fresh- 
water and land pulmonates simply call this region an enlargement of the 
ovisperm duct, but it is distinctly glandular and different from the ovi- 
sperm duct in structure. It also occupies the position above the prostate, 
where it lies in other animals. It is recognized as the seminal vesicle by 
Simroth (1912, p. 501) and by Larambergue (1939, p. 94). Taylor (1900, 
p. 359) calls the small sac-like organ into which the duct of the albumen 



6 The MoUuscan Fcunily Planorhidae 

gland enters, the seminal vesicle, but as this organ is an adjunct of the 
male system in all animals it could scarcely be located in an organ of the 
female system. The swelling near the albumen gland is the carrefour. The 
seminal vesicle is variable in form in the different species and genera and 
provides another feature for classification purposes (see plate 35, fig. 5, 
Carinifex jacksonensis; plate 1, fig. 1. Planorbis planorbis; plate 14, fig. 7, 
Gyraulus albus). 

Female Organs. The vagina ( VG) , usually a thick walled, wide tube, 
passes imperceptibly into the uterus (U) which is usually much enlarged. 
A large sacculated body, the nidamental gland (NG, sometimes called 
egg gland) follows the uterus and is usually placed over the uterus and the 
oviduct. The oviduct (OD) lies back of the gland and is much narrowed 
as it passes backward to join the ovisperm duct. The method of junc- 
tion of the oviduct and sperm duct with the ovisperm duct varies in 
different genera. 

The albumen gland (AL) is a large, more or less elongated organ, com- 
posed of many small alveoli. In its natural position it lies over the stomach 
and a loop of the intestine passes under it causing a channel to be formed 
on the under side of the albumen gland (plate 38, fig. 9, Menetus opcrcu- 
laris; plate 15, fig. 1, Gyraulus hirsutus) . The organic relations between 
the albumen gland and the oviduct are somewhat complicated. A small 
duct extends from the albumen gland and enters a large bulbous swelling 
which is attached to the end of the oviduct before that organ combines 
with the sperm duct to form the ovisperm duct. This gland or bulb is the 
carrefour which receives the products of the albumen gland and from which 
they enter the oviduct (see plate 34, fig. 6, Carinifex ponsonbyi; plate 35, 
figs. 6, 7, Carinifex jacksoriensis) . Taylor (1900, p. 359) erroneously calls 
the carrefour the seminal vesicle. 

The spermatheca or receptaculum seminis (S) is a bulbous or pear- 
shaped organ with a narrow duct of variable length which enters the 
vagina at its junction with the uterus. Its function is said to be that of 
receiving the sperm (in the form of a spermatophore) during copulation 
and to store it safely until the eggs descend from the ovotestis, at which 
time they are fertilized by the stored sperm. The vagina is usually very 
short but may be of considerable length in some species. 

Organs Common to Both Systems. The ovotestis (OT) is embedded 
in the liver and fills about one whorl of the shell. It varies in form much 
as does the prostate, the two organs being more or less synchronous in this 
respect, a valuable feature in classification. In the Helisomatinae it is 
many-lobed, the diverticula branching fan-wise from the ovisperm duct 
(plate 27, fig. 4, Helisoma campanulatum ; plate 34, fig. 9, Carinifex pon- 
sonbyi). In the Planorbinae and Scgmentininae the diverticula are in pairs; 
the two diverticula are attached directly to the ovisi)erm duct (plate 
16, fig. 9, Gyraulus deflectus obliquus) . During the breeding season the 
diverticula may be filled with both ova and sperm, the ova either ripe 
for expulsion or developing (plate 10, fig. 2, OT, Drepanotrema hofjmani). 
The ovisperm duct is a small tube of variable length, enlarged near the 
middle to form the seminal vesicle. 

Both ova and sperm are produced in the same diverticulum. They are 
said to arise simultaneously from indifferent epithelial substance and may 



General Morpliology 7 

be found developing together in a single diverticulum (see Crabb, 1927, 
p. 75). It is thought by most malacologists that the spermatozoa ripen 
first, descend during copulation, and are stored in the spermatheca of the 
female system until the ova ripen and descend through the oviduct, and 
that fertilization occurs when the ova and sperm meet in the lower part of 
the uterus or vagina, just before the depositing of the egg capsule. Some 
cytologists declare that fertilization occurs in the ovotestis diverticulum 
and that the fertilized egg descends and is deposited without the necessity 
for copulation. See Clapp 1927 for a discussion of this subject. Typical 
eupyrene spermatozoa and nucleated o^'lm^: of Gyraulus circumstriatus 
(TryonI are shown on plate 52, figs. 14-16. 

The Penial Complex, The male organ, which I have called the penial 
complex, contains a number of features which are of great value in sys- 
tematic diagnosis. The whole organ is divisible into two parts, a lower 
swollen or bulbous portion called the preputium (PR) and an upper portion 
called the vergic sac (VS). The latter contains the penis proper or verge 
(V), which may be short and fat (plate 1, fig. 5, Planorbis planorbis) or 
very long and narrow (plate 10, fig. 6, Drepanotrema hoffmani). All 
grades of length and diameter between these extremes are to be found in 
the different genera. 

The verge may be modified at its extremity by the presence of a dagger- 
like object called a stylet (plate 16, fig. 6, ST, Gyraulus deflectus obliquus; 
plate 14, fig. 1 and fig. 6 Gyraulus albus) . In these examples the outlet 
canal for the passage of the spermatozoa is at the side. In other genera 
there may be a fleshy papilla or appendage at the end of the verge (PA) 
with the outlet of the canal in the middle at the base of the papilla (plate 
2, figs. 5, 6, Segmcntina nitida) . In still other genera the termination of the 
verge is simply rounded with the canal outlet in the center (plate 38, fig. 15, 
Moietus cooperi calioglyptus) . Other slight modifications are found in 
some genera. 

Between the vergic sac and the preputium there is an organ which I 
have called the diaphragm (D). This is a muscular ring which separates 
the two parts of the penial complex. This may be a simple ring with a 
central perforation (plate 39, fig. 7, Menetus cooperi) or it may be a 
dependent papilla (plate 23, fig. 6, Helisoma anceps; plate 24, fig. 10, 
Helisoma trivolvis; plate 16, fig. 5, Gyraulus deflectus obliquus). The 
preputium always has several vertical ridges on the inside called pilasters 
(PL) which may serve to guide the verge or the penial gland during 
protrusion. 

In 1926 (Trans. Wis. Acad., V. 22, pp. 200, 201) the writer called atten- 
tion to a peculiar gland found in the preputium of the genus Helisoma. 
Subsequent study has shown that this organ is found in several other 
groups or genera of American, Euroi)ean, and Asiatic jilanorbids. This 
gland is of variable shape, iiyriform, rounded, or elongated (plate 23, fig. 
2, Helisoma anceps; plate 24, figs. 8 and 14, Helisoma trivolvis). In sec- 
tion it is seen to be cup-shaped, to be lined on the sides with folds and to 
have many small folds in the bottom of the cup. The gland is attached to 
the inner wall of the preputium either midway between the male opening 
and the muscular ring (diaphragm), or somewhat nearer this ring in some 
species. 



8 The Molluscan Family Planorhidae 

From the base of the cup, and piercing the integument of the pre- 
putium, is a duct of variable length (DC) , which, if long, is folded on the 
outside of the preputium (plate 27, fig. 9, Helisoma campanulatum) ; or, 
if short, simply lies on the surface of the preputium (plate 23, fig. 2, 
Helisoma anceps) . When coiled on the outside of the preputium it is bound 
to that organ by short muscles. Sections through the cup are shown on 
plate 23, fig. 1, plate 24, fig. 1, and plate 27, fig. 1. The duct terminates 
at the muscular ring or diaphragm (D), pierces the wall of the lower part 
of the vergic sac, and terminates just above the ring (plate 23, fig. 6, 
Helisoma anceps; plate 24, fig. 10, Helisoma trivolvis) , or in a groove in 
the ring (plate 36, fig. 9, Parapholyx effusa) . 

The function of the penial gland is at present insufficiently known. It 
was once thought by the writer to be connected with the formation of the 
spermatophore and was called the spermatophore gland (Baker, 1931, 
p. 581), but this belief scarcely agrees with the structure of the gland. In 
section this organ is seen to have two parts, each of which may have a 
different function. In Helisoma trivolvis (plate 24, fig. 4) the gland shows 
a large cup-shaped cavity, the walls of which are lined with vertical folds 
(GF). The bottom of this cup is. lined with folds laid crosswise. The long 
duct begins at the bottom of the cup and terminates in the vergic space 
(DC) of the vergic sac (VS) just above the muscular ring or dia- 
phragm (D). 

In some species, as Helisoma duryi and its varieties, the duct begins in 
a small cavity or cup at the end of the gland (plate 33, figs. 3, 10), the 
walls of which have vertical folds. The larger cup-shaped cavity has no 
connection with the smaller cavity or its duct. In some species, notably in 
the genus Menetus, there is no external duct, connection with the vergic 
space being effected by an open channel (plate 42, figs. 3, 4). Another 
group of Menetus has a short duct on the inside of the preputium (plate 
39, fig. 7). In Menetus and some other groups there is a small channel in 
the muscular ring (plate 39, fig. 7, D). Helisoma anceps shows this feature 
well (plate 23, figs. 2, 6). Parapholyx effusa klamathensis (plate 36, figs. 
9, 10) also shows the canal in the muscular ring. 

It appears possible that one of the functions of the penial gland might 
be to expand the opening in the muscular ring or diaphragm which is 
normally nearly or quite closed, and prepare it for the protrusion of the 
verge. The penial gland duct possibly carries a fluid, secreted by the ver- 
tical folds in the gland cup, to the diaphragm to facilitate the passage of 
the verge. 

But there is another function of the gland. It has been observed that 
during copulation not only is the verge extruded from the male opening, 
but also the whole penial gland. This has been observed in many species of 
Helisoma (H. duryi normale, plate 33, fig. 16; H. trivolvis lentuni, plate 29, 
figs. 7, 11, 12; Promenetus exacuous, plate 41, fig. 9). In all species of 
Planorbidae the verge is extruded during copulation. In a specimen of 
Drepanotrema lucidum examined (plate 11, figs. 1, 2, 6, 7) the verge and 
penial gland protruded together from the male opening. It is probable that 
the gland portion with the cup-like cavity lined with vertical folds is an 
excitatory organ or sarcobelum, for in the species possessing this gland 
there is no special apparatus for this purpose such as occurs in other species 



General Morphologij 9 

which have a horny stylet or fleshy papilla at the end of the verge 
{Gyraulus, Anisus, and other genera). 

Another feature observed in connection with the penial gland is that 
the i)enial complex is often seen in a bilobed condition, the gland being 
pushed upward in the preputium causing the vergic sac to appear as 
though attached to the side of the preputium. This condition occurs mostly 
in HcUsoma (plate 25, figs. 1, 6, 7, 9; plate 24, figs. 1, 2). The evolution 
of this feature was observed in specimens of Helisoma ccunpanulatum and 
is shown on phite 27, fig. 7 being the nonual form and figs. 6, 5, and 8 
showing the gradual change to the bilobed condition. 

Much remains to be learned about the function of the penial gland. 
Observations of the living snail in aquaria should help to solve some of 
the questions. It may be observed, however, that this is not so easily ac- 
complished as might be supposed. More than a dozen acjuaria were kept 
under observation by the writer for several years, and while the animals 
were seen in apparent coitus on several occasions, the protrusion of the 
gland was not seen. Perhaps histological studies would help, especially 
before and after breeding. The subject is worthy of a doctor's thesis. 

As was recorded in the study of the family Lymnaeidae (Baker, 1911), 
there is great variation in the form of the genitalia of the genera of the 
family Planorbidae. As in the Lymnaeidae, also, this modification occurs 
mostly in the male organs, principally the penial complex, but includes 
also the ]:)rostate and seminal vesicle. The female organs are uniform in 
position and shape, only the spermatheca and its duct vary in form 
and length to any degree. The male organs, therefore, afford useful features 
upon which to base a natural classification of the family, since the 
characters of the different groups are constant and uniform. 

[b] The Digestive System 

The digestive system of the Planorbidae is similar in many respects to that 
of the family Lymnaeidae. The system naturally divides into three parts, 
the first consisting of the buccal sac, the oesophagus, and the salivary 
glands, the second part the region of the stomach with the liver connec- 
tions, and the third part the intestine and rectum (see fig. 1, plate 48). 

The buccal sac is usually pear-shaped, the oesophagus entering it at 
the upper middle portion. There are retractor and protractor muscles and 
nerves received from the buccal ganglia. The salivary glands are paired, a 
duct entering the buccal sac on each side near the oesophageal connection. 
The salivary glands, usually cylindrical and elongated, are composed of 
many small lobules. The two glands are joined behind and form a con- 
tinuous loop or ring. These organs are very uniform in the different species 
of the family (see plate 70, figs. 12, 13). The oesophagus is usually rather 
long (about one-fourth as long as the intestine), beginning as a tube of 
small diameter and enlarging as it approaches the stomach region. 

The stomach is a large muscular body composed of three parts, first 
the crop, w'hich is an enlarged portion of the oesophagus, then the gizzard, 
which is an indistinctly bilobed body of large diameter, and third the 
pyloris, or opening into the intestine. The gizzard is not as distinctly 
bilobed as in Lymnaea but is of the same nature. When ojiencd it is found 



10 The Molluscau Family Planorhidae 

to contain small particles of siliceous matter, evidently sand taken in with 
the food to serve for the breaking up of the ingested food. 

On the under side of the pyloris, near the duct of the liver, there is a 
finger-like process or blind sac which appears to be the stylotheca con- 
taining the crystalline style. This blind sac is present in all species of the 
family examined. Internally the sac contained a gelatinous substance or 
was empty. The liver or digestive gland covers the posterior part of the 
stomach region in its natural position. It has two unequal lobes which 
form the posterior part of the animal and in which the ovotestis is con- 
cealed. The liver is composed of a great number of small lobules, more or 
less digitiform. It is well supplied with blood vessels which form a plexus 
on and in the organ. A large duct enters the pyloric portion of the stomach 
at the point of junction with the blind sac. 

The intestine is very long. It bends around the stomach from the end 
of the pyloris and passes backward for a distance. It then forms a single 
loop wdiich bends forward and extends to the fore part of the animal on 
the left side (the right side in the Lymnaeidae). The rectum, the greatly 
enlarged portion of the intestine, supports a central ridge or crest on the 
upi5cr side which extends to and over the pseudobranch. The anal opening 
is always near this ridge on the pseudobranch, to the right and above this 
organ. 

Variation in the digestive system is noted only in the form of the 
stomach region, short and rotund in some species (plate 48, fig. 1, Helisoma 
trivolvis) or elongated and narrow in other species (plate 48, fig. 8, 
Bathyomphalus contortiis) . The loop of the intestine sharply borders 
the stomach in some species (fig. 1) though in some species it extends 
forward without a loop (fig. 8). 

[1] The Jaw 

The mouth of the Planorbidae is provided with two important organs 
which afford characteristics for classification, the jaw and the radula. The 
horny jaw lies in the upper part of the mouth at the fore end of the buccal 
sac (plate 70, fig. 13). As in Lymnaea, the mouth is somewhat T-shaped 
in repose. In the upper part of the T lies the superior jaw, which is wide 
and low, of a brownish color, striated vertically on its front part, the 
striations producing a saw-like condition on its lower, cutting edge (plate 
49, fig. 1, Helisoma anceps) . The lateral jaws, two narrow, brown, horny 
ribbons, emargin the lips or sides of the mouth. They are connected with 
the lateral margins of the superior jaw by a narrow projection from the 
upper part of the lateral jaws. These side jaws form a question-mark 
figure, as will be noted in the figures on plate 70. The jaws, superior and 
lateral, are attached to a cartilage which in turn is attached to the roof of 
the mouth. The jaws are moved by several distinct muscles. 

The jaws of the Planorbidae fall into two principal types or variations. 
The most common is the group described above, with large superior jaw 
and two smaller lateral jaws. Another type is horseshoe-shaped and in this 
there is but one division which appears to represent the fusion of the 
lateral and superior jaws of the first type. The striations of the superior 
jaw of the first group become separate vertical plates in the second group, 
producing a segmented jaw. This segmentation extends to the lower part 



General Morphology 11 

of the side of the horseshoe, showing that tlie hiteral jaws are inokidcd in 
the segmentation (see plate 50, fig. 16, Gijraidus parvus). 

A peculiar jaw, not included in the usual segmented type of the family, 
is that of Cariuife.T in which the jaw is b()w-shai)ed (or roundly horseshoe- 
shaped) and is composed of many narrow plates fastened to a heavy 
cartilage (plate 49, fig. 19, Carinifex ponsonbyi; fig. 18, Carinifex jackson- 
ensis) . Althcnigh belonging to the subfamily Helisomatinae the jaw is prac- 
tically of the Planorbinae type. Figure 17 on plate 49 shows the large size 
of the cartilage in this genus (C. iacksonensis) . 

This type of segmented jaw is suggestive of the polyplacognath group 
of land snails. It is said to be a very ancient type of jaw which would seem 
to indicate that the Planorbinae group of the family is more ancient than 
the Helisomatinae group (except Carinifex which has the primitive form of 
jaw). The marginals of the radula also indicate a primitive form of radula. 

[2] The Radula 

The radula of the Planorbidae is ribbon-like as in the Lymnaeidae. It 
lies on a subquadrate cartilage near the rear end of the buccal sac. The 
front end of the radula extends toward the mouth of the snail and the rear 
end is bent downward into a radular sac which forms a rounded protrusion 
or bump at the back of the buccal sac (see plate 70, figs. 12, 13). The 
radula grows forward from this sac as the functional teeth at the front 
end of the ribbon become worn by use. There are protractor and retractor 
muscles which iiull the radula backward and forward, over its cartilage, 
during the act of cutting u\) food particles. In use, the radula is moved 
from behind forward, like the tongue of a cat lapping food from a plate, 
as described by Sterki many years ago. 

The lingual ribbon of the Planorbidae carries many teeth in transverse 
rows as in the family Lymnaeidae. There may be as many as 200 rows 
with 85 teeth in a row or a total of 17,000 teeth in one ribbon. The central 
tooth is always bicuspid and in some groups (as in Drepanotrema) there 
are one or more accessory cusps on either side of the central cusps. There 
is a series of duplicating teeth on each side of the central tooth. This row 
is divisible, as in the Lymnaeidae, into lateral, intermediate, and marginal 
teeth. The lateral teeth are usually tricuspid and comprise an inner, short 
entocone, a large median mesocone, and a smaller outer ectocone (see plate 
57, fig. 1). The cusps are usually dagger-like and may be wide or narrow. 
The intermediates are those teeth between the typical lateral and marginal 
teeth which show certain modifications, as splitting of the ectocone or 
entocone into smaller cusps. The marginals are usually somewhat claw-like 
with a variable number of small cusps. The mesocone usually persists in 
the earlier marginal teeth and may be recognized by its large size and 
central position. 

The law of mesometamorphosis applies to the Planorbidae as well as to 
the Lymnaeidae. As stated by Pilsbry this law is as follows: 
All modifications of the teeth proceed from the median line of the radula outwards 
toward the edges, the outer marginal teeth being the last to be modified (Guide to 
Study of Helices, p. xiii). 

The marginals of the Planorbidae are of the same ])rimitive type as are 
those of the Lymnaeidae, showing a close relationshii) between these two 



12 The Molluscan Family Planorhidae 

families and also their common descent from the tectibranchiate stock of 
marine mollusks. The lateral teeth of the Planorhidae show a wider degree 
of variation than do the lateral teeth of the Lymnaeidae, indicating, per- 
haps, that the Planorhidae may be somewhat younger in development. 

In studying the teeth of the Planorhidae it must be remembered that 
only the unworn teeth show the true characteristics of the radula. Also the 
teeth must be in their natural position on the radula ribbon and not tilted 
or otherwise disturbed. 

The Planorhidae are divisible into two groups by the form of the 
marginal teeth. One group, including the genus Helisoma and other 
divisions of the subfamily Helisomatinae, have long and narrow reflec- 
tions reaching far below the base of attachment and with the distal end 
and the outer margin multiserrate (see plate 57). The other group, includ- 
ing the genus Planorhis and other divisions of the subfamily Planorbinae 
as well as some of the subfamily Segmentininae, have short, wide reflec- 
tions high up on the base of attachment and only a few^ serrations or cusps 
on the lower margins (see plate 69). 

The lateral teeth are very uniform in both groups, these being mostly 
tricuspid, the cusps rounded or sharp and dagger-like. In several groups 
(as Drepanotrema and Segmentina) the laterals are modified by the 
addition of several cusps, causing the teeth to be 6 or 7 cuspid. These 
exceptions appear to be due to a splitting of the three cusps of the normal 
lateral teeth (entocone, mesocone, ectocone) found in the majority of 
planorbid genera. As with the other organs, the radulae offer sound criteria 
for classification purposes. 

[c] The Renal System 

The kidney or renal organ (nephridiumt of the family Planorhidae is a 
large and conspicuous part of the snail's anatomy, occupying a consider- 
able portion of the body whorl of the animal. It lies to the left of the 
lung cavity, the genitalia being between the kidney and the ureter (see 
plate 14, fig. 4, U, NG). Viewed from the ventral side, the kidney consists 
of two parts, a small upper saccular portion with the pericardium at the 
right (SK) and an elongated lower portion (TK). A section through the 
middle of this portion of the kidney (plate 44, fig. 9) shows a central tube 
or lumen flanked on each side by a large vein, the pulmonary vein on the 
right side (AP) and the renal vein on the left side (RA). The central 
tube, the tubular portion of the kidney, is regularly marked by internal 
septa which project into the lumen for a greater or less distance. The 
tubular portion is surrounded by thick walls of spongy tissue, the most 
conspicuous part being a distinct ridge (RK) . To the left of this ridge (in 
the section) there is another conspicuous ridge on the roof of the mantle. 

At the lower end of the tubular portion is the short ureter (UR). This 
is a small tube which turns to the left, usually more or less upward, and 
discharges into the mantle cavity. The figures on plates 44 to 47 show the 
various forms of ureter and the relationships of the different parts of the 
kidney. In 1940, Mattox, working on another group of snails, pointed out 
the fact that the kidney may reflect specific characters. 

A series of sections through the kidney of Australorbis glabratus (plate 
45, figs. 7 to 11) show the internal form of the kidney at different points 
in its length. In fig. 1, plate 45, an arrow indicates the place where each 



General Morplioloyy 13 

section is made. Figure 7 (E) is a section through the sacculate part of 
the kidney below tlie pericardium, and shows the lumen partly filled with 
folds extending from the walls of the kidney. In fig. 8 (D) the section 
shows the tubular portion of the kidney with a few folds extending from 
the walls, also the large pulmonary vein at the right and the smaller renal 
vein at the left. In figs. 9 and 10 (C, B) the same features are shown. In 
fig. 11, near the lower part (A), the kidney is flattened and broadened 
and the veins are smaller. All figures show the variation in the form of 
the ridge in different portions of the kidney. The blood vessels (veins) lie 
in close proximity to the tubular jiart of the kidney and pick up the blood 
to be carried to the heart. 

The folds iu' the tubular portion of the kidney are metameric in their 
presence and one section may pass through a portion of the kidney where 
these are present, or it may pass between two sets of folds, as shown in 
figs. 16 and 17 on plate 45, as well as on other plates. The ridge on the 
kidney is mostly confined to members of the subfamily Helisomatinae 
and offers a valuable criterion for the separation of this planorbid group. 
The Planorbinae are mostly without this ridge. 

The ureter of the Planorbidae is described as straight, but no exit of 
this nature was found in any species examined. All had a short ureter, 
partly reflexed, as shown in the figures on the plates. 

[d] The Circulatory System 

The circulatory system of the Planorbidae is similar to that of the Lym- 
naeidae and other Basommatophorous Pulmonata. The heart lies to the 
right of the kidney (instead of to the left as in Lymnaea) and consists of 
a ventricle and an auricle enclosed in an oval pericardium (plate 44, fig. 2, 
PC, AU, VT). The aorta (AO) extends backward from the ventricle and 
divides into two branches or arteries, the visceral artery which supplies 
the digestive, genital, and other systems in the posterior part of the body, 
and the cephalic artery which bends around and forward, carrying blood 
to the organs in the head, foot, etc. These arteries branch frequently, 
the branches becoming smaller, and terminate in contact with the venous 
system either by small arterioles or through lacunae or blood sinuses which 
connect the arterial system with the venous system. 

The venous system consists of blood vessels which convey the blood 
back to the heart after circulation through the kidneys, lung, and other 
parts of the system. A large branchial vein borders the kidney on the right 
side, carrying blood to the auricle. A large renal vein also borders the left 
side of the kidney, entering the saccular portion (see plate 44, fig. 2, AP, 
RA). Venous sinuses are present and store the blood after circulation to be 
carried to the renal and respiratory systems for purification. 

In the Planorbidae the blood (haemolymph) contains a substance 
(haemoglobin) which gives it a pinkish or red color. This is an active 
substance occurring abundantly in the respiratory system and differs from 
the bluish blood (liaemocyanin) which occurs in most mollusks. Its pres- 
ence in Planorbis is said to be associated with the poorly oxygenated hab- 
itat occui^ied by most species of this group in stagnant pools or lakes and 
ponds poorly supplied with oxygen. This statement, however, is open to 
question, since many species of the Planorbidae live in habitats abundantly 



14 The Molluscan Family Plauorbidae 

supplied with oxygen, in company with Lymnaeas and other fresh water 
piihnonates. The pseudobranch is probably helpful in supplying oxygen 
to the blood, as it is highly vascular (plate 14, fig. 4, P). 

[e] The Respiratory System 

Respiration in the Planorbidae is effected as in the Lymnaeidae and other 
aquatic pulmonale mollusks. Free air is admitted into a large mantle 
cavity abundantly lined with blood vessels forming a plexus on the dorsal 
wall of the mantle cavity. This lung cavity lies on the right side of the 
mollusk, next to the kidney, and is bordered on the left by the pulmonary 
vein (plate 44, fig. 2, L). The lung cavity is placed on the right side of the 
body in sinistral species iPlanorbis, Physa) but on the left side in dextral 
species (Lymnaea). 

In the Planorbidae the presence of the secondary brancliium, the 
pseudobranch, enables the animal to respire without coming to the surface. 
This organ is of various shapes, but is always an outgrowth of the 
branchial cavity walls and lies to the left of the pulmonary siphon to 
which it is attached (plate 14, figs. 3, 4, P). It may be a simple rounded 
fold or it may be flat with a distinct ridge down its center. It is abundantly 
supplied with a plexus of blood vessels which absorb oxygen from the 
water. 

The rectum passes through the pseudobranch and its outlet (anus, A) 
is usually above and about at the middle of the pseudobranch. The rectum 
usually has a large crest or ridge on its upper surface which diminishes 
in size at the lower part where it extends over and to the edge of the 
pseudobranch (see plate 25, fig. 3, Helisoma pilsbryi; plate 28, fig. 8, 
Hclisoma scalare; plate 35, fig. 4, Carinifex jacksonensis) . 

The breathing orifice or pulmonary siphon (pneumostome) is an out- 
growth of the mantle which is capable of forming a tubular conduit or 
siphon through which free air may be admitted to the lung (see the 
plates mentioned above). The respiratory, renal, and circulatory systems 
are intimately connected and should be considered together to understand 
the conditions governing the respiration and blood circulation of the 
animal. 

[f] The Nervous System 

The nervous system of the family Planorbidae differs little from that of 
the family Lymnaeidae (see Baker, 1911, plates 1 and 5). A nerve ring 
surrounds the oesophagus posterior to the buccal sac (plate 48, fig. 18). 
There are two cerebral ganglia above the oesophagus (CG). Below the 
oesophagus there are two pedal ganglia (PG), two buccal ganglia (BG), 
two visceral ganglia, and a single abdominal ganglion. Two pleural ganglia 
are connected with the visceral, pedal, and abdominal ganglia. The left 
cerebral ganglion sends nerves to the penial complex (plate 48, fig. 17, 
Helisoma anceps) , which divide to send branches to the vergic sac, penial 
gland duct region, and retractor muscle, as well as to other parts of this 
comj^lex. 

In the Planorbidae these nerves are sent off from the left instead of the 
right ganglia, because the group is sinistral. In the Lymnaeidae, a dextral 
group, the nerves arise from the right ganglia (see Baker, 1911, plate 5). 



General Morphology 15 

[g] The Muscular System 

The muscular system of the family Planorbidae does not differ from that 
of the family Lymnaeidae except in i)ositions due to the sinistrality of the 
animal. The most important muscles for classification purposes are those 
of the male generative system. 

C. THE SHELL 

The shells of the Planorbidae are mostly orb-shaped, wheel-shaped, or 
disc-shaped, rarely becoming a conical spiral as in Lymnaea and Physa. 
Several physoid types occur, as the Helisoma scalare of Florida. Such types 
sometimes occur in other species of the family as abnormal or pathologic 
forms, and have been noted in the genera Helisoma and Carinifex. Scalari- 
form individuals may also occur in any species and have been noted par- 
ticularly in the smaller species of the genus GyrauliLS. 

The shell may be closely coiled, like a watch spring, or loosely coiled, 
and of few or many whorls. It may be so fiat that one wonders how an 
animal can find enough room to function in so small a space, as Drepano- 
trema cultratum, or it may be almost globose, as Helisoma pilsbryi. It may 
be as thin as paper or thick and very solid. 

The shells of the larger speLcies^_especially in_ Helisoma, are carried 
almost perpendicularly as in jHelisojnq trivolvisjnaa^o^tomum (shown on 
plate 70, fig. 7) , or it may lie'ahiiost flat as in Planorbida^nksi (shown 
on plate 70, fig. 11). In all species of the family Planorbidae the ^nital 
organs are on the left side^ -and the animal is sinistral. But the shells are 
not all strikingly Sinistral. Such large groups as Helisoma, Planorbarius, 
and Indoplanorbis are obviously sinistral, usually exhibiting a distinct 
right and left side- wh^ii ia loconiption. But the smaller species are tipped 
to one^ side, to the left, and are apparently dextral and are usually de- 
scribed as pseudodextral or ultradextral. In such species the upper side 
(right) is umbilical and the lower side (left) is apical. These shells, while 
truly sinistral, appear as dextral. In most works on this family the shells 
have all been considered dextral and figured as such. Quite a literature 
has developed in the controversy as to whether the shells of Planorbis are 
dextral or sinistral (see Baker, 1896. Jour. Cincinnati Soc. Nat. Hist., 
19, p. 45). 

In size the planorbids range from the tiny Armiger crista, less than 
2 mm. in diameter, to the large Helisoma trivolvis macrostomum, which 
attains a diameter of 30 m m. The whorls may be rounded on the periphery 
or this region may be sharply carinated or squarely flattened. The lower 
(umbilical) surface may be so flattened that no umbilical opening is indi- 
cated, or it may be deeply indented forming a distinct umbilicus. Sutures 
may be deeply indented or scarcely visible. The aperture is most frequently 
rounded, ovate, or half-moon shaped. It may be armed with lamellae or 
entirely free from such obstructions. The outer lip may be thin and sharp 
or it may be strengthened by a heavy ridge or callus. There may be, also, 
more or less of a callus on the parietal wall. As most species are planorboid 
in form there arc few modifications of the columella, as are found in the 
familv Lvmnaeidae. 



16 The Molluscan Family Plauorbidae 

The sculpture of the planorbid shell consists mostly of growth lines 
which may be very fine and thread-like or coarse and rib-like. In some 
species there have been developed costae or ribs more or less evenly dis- 
tributed. In a few species the epidermis forms paper-like crests or frills, as 
in Helisoma anceps royalense. Spiral impressed lines are found in most of 
the species of the family. These are usually rather heavy and conspicuous 
but in some species they are very fine. In a few species the spiral lines are 
very faint or absent, as in Menetus opercularis. Malleated individuals are 
comparatively rare in the Planorbidae although they are common in the 
Lymnaeidae. The epidermis or periostracum of the planorbids is usually 
rather thick and heavy. In some groups the shell appears devoid of an 
epidermis, the surface being shining and waxy. The remarks on sculpture 
in the Lymnaeidae Monograph (pp. 3, 4) apply equally well to the 
Planorbidae. 

The color of the shells of the family Planorbidae is usually some 
variety of horn color, light or dark. In some groups, as Australorbis, the 
color is rich brown or chestnut. Some shells are light milky in color. A few 
species border on red, others are ashy. The range of color is about like that 
in the family Lynmaeidae, but there are no species known comparable to 
the greenish shell and purplish aperture of Bulimnea magasoma, the hand- 
somest of the fresh w^ater pulmonates. Zebra markings occur among the 
planorbids as among the lymnaeids. 



II. 
GENERAL ECOLOGY 

ECOLOGY now has such a wide significance and includes so many 
diverse subjects that it is necessary to define what is embraced 
under this term in this chapter. It is here made to include every- 
thing that affects the animal either from external or internal sources, in- 
cluding such subjects as the habitat, climate, altitude, chemical conditions 
of the water body, pollution, parasites, relations in food chains, reproduc- 
tion, development, etc. 

GENERAL ENVIRONMENTAL CONDITIONS 

Representatives of the family Planorbidae may be found in almost any 
body of fresh water, from the largest lakes to the smallest pools. Streams 
of all sizes harbor one or more species of the family. Certain groups, as 
Menetus, Planorhula, Tropicorbis, and some Gyraulus, are abundant in 
small pools which may become wholly or partially dry during diy seasons. 
]\Iany of the large forms, such as Helisoma campamdatum, Helisoma 
corpulentum, Helisoma pilsbriji, and some varieties of Helisoma anceps, 
prefer larger bodies of water like the larger lakes. Helisoma trivolvis is 
common in small lakes or bays of larger lakes, in shallow areas where 
the shore is bordered by Typha and sedge, where food in the form of algae 
and other vegetation is abundant. In such habitats the snails may be 
seen with the foot attached to the under side of the surface film, the shell 
hanging downward, the animal busily eating such small organisms as may 
lie on the surface. In Florida, members of the subgenus Seminolina live in 
limestone pools of limited size. 

Almost all of the members of the family Planorbidae are littoral 
animals and are not usually found in water deeper than fifteen feet, the 
usual limit of rooted vegetation in water bodies. The maximum numbers 
occur in shallow areas not exceeding six feet in depth. A few inhabit deeper 
water and in the deep lakes of Europe and Asia, as lakes Geneva, Con- 
stance, and Leman in Switzerland, Lake Balaton in Hungary, and Lake 
Baikal in Siberia, they may occur in abysmal depths of from forty to 350 
meters. In our own lakes, deep dredgings have produced no members of 
the family Planorbidae. The family is on the whole a distinctly shallow- 
water group. 

The Planorbidae are able to withstand unfavorable features of their 
environment better than most groups of mollusks, owing to their ability to 
breathe free air. Thus water of some alkalinity and salinity, as well as 
water containing sewage, may be used by these animals successfully as 
habitats. The Lymnaeas also share this ability to live under unfavorable 
conditions. It has been observed, however, that chemicals and oil, also 
wood wastes from factories, are inimical to the Planorbidae and Lym- 
naeidae and none have been seen which could resist this deadly type of 
habitat. Clear, cold mountain streams, especially if rapid, contain no 
planorbids, and usually no other mollusks, as far as personal observations 
have indicated. ]\Iany such in New England have been examined and a few 
in Idaho and ^Montana. 

17 



18 The Molluscan Family Plauorbidae 

Altitude does not seriously affect the distribution of the members of the 
family Planorbidae. In the Rocky Mountains they occur in lakes at alti- 
tudes of from 9,000 to 10,000 feet. Lake Titicaca, in Peru, which contains 
many mollusks, including a peculiar group of Planorbidae [Taphius) is 
at an altitude of 12,846 feet. The Swiss lakes are at comparatively high 
altitudes as are also some of the lakes of Asia which contain moUusk 
faunas of some size. 

Quite a literature has accumulated on the general ecology and par- 
ticular habitat relationship of the Planorbidae and other fresh-water 
mollusks. The remarks on tlie lymnaeas in the 1911 monograph on that 
family may be consulted with advantage. A number of special papers and 
books have been published which bear on this subject. These are listed 
in the bibliographv and may be consulted under the following names: 
Adams, 1909; Baker, F. C.^ 1910, 1911, 1916, 1918, 1920, 1922, 1924; 
Dybowski, 1875; Forel, 1869, 1874; Lindholm, 1909, Tavlor, J. W., 1894- 
1900. 

VARIATIONS IN DIFFERENT ENVIRONMENTS 

The planorbid snails do not exhibit as much variation due to differences 
in the environment as do the Lymnaeidae (see Baker, 1911, pp. 29-32). 
The shell aperture often increases in size in large lake localities where the 
animal is subject to heavy wave action. This may be observed in Helisoma 
anceps percarinatum and in Helisoma anceps sayi which are lake dwellers 
in contrast with typical Helisoma anceps which is usually a river or creek 
inhabitant. Helisoma canipanulatum davisi is a small pool or swamp 
dweller while typical Helisoma campanulatum is a lake inhabitant and 
usually has a larger, more expanded aperture. Some species of this family 
show preferences for particular types of habitat. Thus Planorbula armigera 
is usually found in ephemeral pools or small bodies of water, or in pro- 
tected places in larger ponds and lakes. Planorbula crassilabris may often 
be found on a lake shore fully exposed to the waves. Promenetus umbili- 
catellus is an inhabitant of ditches, pools, and swampy places, while Pro- 
nienetus exacuous is usually found in larger bodies of water. 

Great variation is often seen in specimens of the same species from one 
habitat. Thus Helisoma duryi seminole, in Lake Eustis and Lake Griffin, 
Florida, varies from a typical planorboid form to a distinct physoid form 
by the elongation of the spire. In Lake Titicaca, in Peru, Taphius andecolus 
exhibits many variations in the form of the aperture, the whorls, and the 
condition of the umbilical region. In Carinifex the individual variations 
are numerous among specimens of one species from the same habitat. 
Among some of the species of the genus Australorbis of South America and 
the West Indies there is often great variation in the axial height of the shell. 

These examples might be greatly multiplied but enough have been pre- 
sented to show that variation is the rule among individuals of the family 
Planorbidae and that this variation may not be due alone to conditions 
of the environment but rather to the inherent 'law to vary' which is found 
in all living things. The family Planorbidae does not appear to offer as 
good a field for the distinguishing of the so-called habitat or ecological 
variations as does the familv Lvnmaeidae. 



General Ecology 19 

LOCOMOTION 

Locomotion in the family Planorbidae is accomplished by the same means 
as in the family Lymnaeidae (see Baker, 1911, p. 32). The method most 
usually observed is that of gliding. Tlie planorbids have been observed to 
rise suddenly and descend abruptly, as do the lymnaeids, by varying the 
amount of air in or on the body or shell. The members of the family are 
usually very active, crawling about on aquarium walls quite rapidly, eat- 
ing everything in their i)ath. In locomotion the planorbids resemble the 
physas more than the lymnaeids. the latter usually being rather sluggish 
in motion. Young and immature planorbids are usually very active, much 
more so than fully mature individuals. 

FOOD 

Like the lymnaeids the food of the planorbids is largely vegetal. Little is 
known, however, concerning the food sujiply of this family. They have 
been observed eating pond-lily leaves (principally Castalia), Potamogeton, 
both the large floating leaf species and the submerged leaf species, and 
algae of various kinds. Both old and young snails will eat avidly of the 
algal scum which collects on the glass sides of an aquarium. The radula can 
be plainly seen, the animal using it from behind forward as described by 
Dr. v. Sterki many years ago. 

Stomachs and crops that have been opened and examined have usually 
contained a quantity of fine sand (especially in the crop) which probably 
helps in grinding the food before it enters the intestine. Ostracods (six in 
one specimen of Helisoma subcrenatum from Pass Lake, Fidalgo Island, 
Washington) , distomids, vegetable fibers, and a quantity of flocculent un- 
digested animal matter have been noted in the stomach. Specimens of 
Helisoma duryi seminole from Florida had the stomach and gizzard filled 
with small grains of sand and nothing else. Some planorbids are scavengers, 
though not to the extent observed among the lymnaeids. No evidences have 
come under observation indicating that the group is carnivorous (see 
Baker, 1911, p. 42 for notes on the food of lymnaeas). 

FOOD FOR OTHER ANIMALS 

Together with other fresh-water mollusks, the family Planorbidae fur- 
nishes food for a large number of other forms of animal life. Chief among 
the animal groups feeding on mollusks are certain species of fish (see 
F. C. Baker, 1916). Fresh-water snails, including planorbids, have been 
found in the stomachs of the following food and game fish: 

Whitefi.sh (Coregotms clupeaformis (Mitchill) ) 
Small Mouth Buffalo (Ictiobus bubahis (Raf.) ) 
Common Sucker {Catostomus commersonii (Lacepede) ) 
Yellow Bullhead (Ameiurus imtalus (LeSueur) ) 
Common Bullhead (Ameiurus nebidosus (LeSueur) ) 
Fre.sh\vater Drum (Aplodinotus grunniens Raf.) 
Pumpkinseed (Lepomis gibbosus (Linn.) ) 
Bluegill (Lepomis macrochirus Raf.) 



20 The Molluscan Family Planorbidae 

Many smaller fish, not of direct value as food or game fish, are yet of 
great value as food for the larger food fish. Many of these include the 
planorbids and other fresh-water snails in their diet. Such small fish known 
to eat snails are: 

Fresh Water Killy {Fmululus diaphanus (LeSueur) ) 

Killifish (Fundulus dispar (Agassiz) ) 

Viviparous Top Minnow {Gamhusia affinis (Baird & 

Girard) ) 
Manitou Darter {Pcrcino caprodes zebra (Agassiz) ) 

Five species of the planorbids have been specifically identified in the 
stomach contents of fish. These are: 

Gyraulus parvus (Say) 
Gyraulus deflectus obliquiis (DeKay) 
Promenetus exacuous (Say) 
Helisoma anceps (Menke) 
Helisoma campanulatum (Say) 

Many species of birds, especially water birds, consume some mollusks 
in their diet. Ducks, such as the Lesser Scaup (Nyroca affinis (Eyt.) ) and 
others feeding in shallow water, eat fresh- water snails. The waders, such 
as the Upland Plover (Bartramia longicauda (Bechst.) ) and the Killdeer 
(Oxyechus vociferus (Linn.) ), feed on snails. The Red-winged Blackbird 
{Agclaius phoeniceus (Linn.) ) has been known to feed on a planorbid 
(probably a Gyraulus) . 

Other groups of animals which include fresh-water snails in their diet 
are turtles, frogs, newts and salamanders, crayfish, leeches, and dragonfly 
nymphs. It is quite probable that many other animals which frequent 
fresh-water snail habitats feed on the smaller species or the young of 
larger species. The stomach contents of many fish and birds have been 
listed as simply snails or Planorbis without identification of the species 
involved. It is obvious that the planorbids, and other snails of the fresh 
waters, are a valuable food source for the larger animals. 

LENGTH OF LIFE 

The life span of the members of the family Planorbidae is not definitely 
known. Specimens of Helisoma trivolvis lentum were hatched in an 
aquarium and lived sixteen months. At this time they were about 8 mm. 
in diameter and had four whorls. An adult lentum has five whorls and is 
about 20 mm. in diameter. It appears possible that these specimens would 
have attained full maturity in another year, or two and a half years from 
time of hatching. Helisoma duryi normale has been hatched in an aquarium 
and has lived for over a year. An adult Planorbarius corneus (the red 
snail) has been kept alive with goldfish for two years. Mature individuals 
of Helisoma trivolvis have remained alive for nearly two years in a well- 
balanced aquarium. 

Just how long any of the planorbids live in their natural habitat is not 
known, four or five years it is probable. The lymnaeids are said to live for 
three or four years. Experiments with the larger snails of the family 
Planorbidae, Helisoma particularly, would be of value. 



General Ecology 21 

THE PLANORBIDAE AS HOSTS FOR PARASITIC WORMS 

The family Planorbidae furnishes some of the best examjiles of the role of 
snails in the life history of certain trematode worms known as flukes. A 
group of worms known as blood flukes {Schistosoma) cause serious dis- 
turbances in man. Three species are known from different parts of the 
world. These parasites require a mollusk as the host of the parthenogenetic 
generations of their life cycle. In this life cycle the Schistosoma in the 
human host lays eggs which are voided in the faeces or the urine. Eventu- 
ally the larvae in the eggs become clothed with a ciliated epithelium, and, 
on coming into water, the egg shell bursts and the miracidium escapes, 
whereupon it begins to swim about rapidly (Faust, 1932. p. 350). 

These miracidia are adapted to specific groups of snails. When in their 
swimming they reach the proximity of certain snails they show a specific 
response to that species of mollusk, probably due to a mucous secretion of 
the animal. In most cases they readily attack, and, in the course of half 
an hour or an hour, penetrate the soft tissues of the snail. In certain cases 
of other trematodes iClonorchis and Metagonimiis) , however, it is neces- 
sary for the embryonated eggs to be swallowed by the snail, whereupon 
they hatch in the lumen of the oesophagus, bore their way through the wall, 
ancl gradually migrate through lymph channels into the lymph spaces 
bathing the hepatic glands. In the meantime, they have metamorphosed 
into the simple sacculate sporocysts. These first generation sporocysts give 
rise to a parthogenetic progeny (either second generation sporocysts or 
rediae) . From this second generation there develops (also parthogeneti- 
cally), a progeny of larvae known as cercariae. Thus, from the penetration 
of a single miracidium there may be developed as many as ten thousand 
or more cercariae. Then later, on reaching maturity, they erupt from the 
tissues of the snail, and, either by direct or indirect routes, produce 
infection in human or reservoir hosts (from Faust, 1932, pp. 350-351). 

Although the three human species of blood flukes (Schistosoma) are 
closely related, they utilize entirely different species of mollusks for the 
l)arthenogenetic stages. Thus, Schistosoma haematobium, with a distribu- 
tion in northern Africa, the Congo Basin, the Sudan, ^Mesopotamia, 
Palestine, Sicily, Corsica, and possibly southern France, parasitizes species 
of the genera Bulinus and Physopsis. Schistosoma japonicum, with a distri- 
bution in China, Japan, Formosa, and the Philippine Islands, uses mem- 
bers of the genus Oncomelania. 

The third species. Schistosoma mansoni, occurring in the same localities 
in Africa as S. haematobium, is also found in northern South America and 
many of the West Indian islands whither it was brought from Africa by 
slaves during the days of the slave traffic. This species originally para- 
sitized small planorbids belonging to the genus now known as Afropla- 
norbis. In the West Indies a genus of large snails known as Australorbis is 
parasitized by the Schistosoma mansoni, which has become a serious pest 
in these regions. A genus of smaller snails, Tropicorbis, related to the 
African group Afroplanorbis, is also used as intermediate host. The small 
snails of the genus Drepanotrema have also been found with cercariae. 
Attempts to use the genus Helisoma as a host for Schistosoma mansoni 



22 The MoUuscan Family Planorhidae 

were unsuccessful, although species of this genus are parasitized by other 
forms of trematode worms. 

Aguayo (1938, p. 210) has summarized the species of snails used as 
intermediate hosts by Schistosoma and other trematodes. Schistosoma 
haematobium is shown to use a species of planorbid, 'Planorbis dufuorii' as 
well as Bulinus and Physopsis. The Schistosoma mansoni intermediate 
hosts include Ajroplanorhis boissyi, A. pfeifferi, A. sudanicus, Australorbis 
glabratus, A. olivaceus, A. antiguensis, Tropicorbis centimetralis, and Dre- 
panotrema cultratus. 

The liver flukes of the genus Fasciola parasitize certain genera of 
Lymnaeidae [Radix, Pseudosuccinea, Fossaria, and Stagnicola) as well as 
one Physa, P. cubensis. The large fluke of the Orient, Fasciolopsis buski, 
which is closely related to Fasciola, uses only the small planorbids belonging 
to the old genus Segmentina which now includes the groups Pohjpylis, Heli- 
corbis, and Pingiella, true Segmentina not being found in the East. Four 
species are listed as intermediate hosts, Planorbis coenosus { = Helicorbis) , 
Segmentina hemaesphaenda {=Polypylis) , and \Seg)nentina sch)naken 
and '*S. nitidella' which have not yet been examined for their anatomy and 
hence their position is doubtful (probably Polypylis) . The value of cor- 
rect specific identifications of the intermediate hosts of these trematode 
worms is of- the first importance as has been clearly indicated by Ingles 
(1933) in a study of the parasites of frogs. 

Elaborate studies have been made by Dr. E. C. Faust of the Depart- 
ment of Tropical JVIedicinc in Tulane University, New Orleans, and by the 
late Dr. William A. Hoffman of the School of Tropical Medicine of the 
University of Puerto Rico, on various phases of the Schistosomiasis man- 
soni problem in Puerto Rico, where the mollusk Aiistralorbis glabratus 
(Say) (=Planorbis guadeloupensis Sowb.) is the intermediate host. For 
these studies see Faust, 1933; Hoffman and Faust, 1934; and Faust, Jones, 
and Hoffman, 1934. 

Papers by parasitologists in which molluscan hosts are mentioned are 
numerous. A few are here indicated. Faust (1918) has observed cercariae 
of four species in Helisoma trivolvis in Illinois and one species in Heli- 
soma sidjcrenatum (not trivolvis, as stated) in ^Montana (Faust 1917). In 
a list of the described cercariae of the United States ( 1919) Faust men- 
tions two species of the family Planorbidae, Planorbis parvus (Gyraulus) 
and Planorbis trivolvis (Helisomci) , as well as several Physidae and 
Lymnaeidae which are known hosts. Fourteen species of cercariae infest 
Helisoma trivolvis and three species occur in Gyraidus parvus. Miller 
(1936) found Helisoma trivolvis from Illinois and Helisoma trivolvis 
lentum (not lantum, typographical error) from Louisiana to be hosts of 
many American cercariae. O'Roke (1917) found Helisoma trivolvis (prob- 
ably the race lentum) carrying cercariae in Kansas, and McCormick 
(1923) found Helisoma trivolvis and Gyraulus parvus to be infested in 
Ohio. Ward (1918), in Ward and Whipple's Fresh-water Biology (pp. 365- 
424), summarizes the cercarial stages of parasitic flatworms, gives keys 
for the determination of the larval stages and indicates the species of 
mollusks which have served as intermediate hosts. Physa, Lymnaea, and 
Planorbis are listed, including many of the Planorbidae. However, this 
text was compiled at the very beginning of studies on trematode life 
histories on this continent. More recently there have been numerous de- 



General Ecology 23 

tailed studies on the stages in fresh-water snails. Many other works might 
he quoted but a sufficient number have been indicated to show the role 
played by the fresh- water snails, particularly the Planorbidae, in the life 
cycle of the trematode worms. Some additional titles are listed in the 
bibliographies accomj)anying the papers mentioned in this chapter. 

During the anatomical investigations made for this work careful note 
was made of the presence of larvae of trematode worms, principally 
cercariae and a few rediae. Over a thousand specimens of mollusks were 
examined but only a few contained parasitic worms. The following species, 
arranged under subfamilies, were observed to be infested. 

Subfamily Planorbinae 

No -spocimens of this subfamily were found with cercariae or rediae. 
Subfamily Segmentininae 

Scgmentina nitida from marshes in a meadow in Czneriakow, a suburb of Warsaw, 
Poland. Sent bj' Mr. A. Jankowski. Cercariae were abundant,- mainly in the ovotestis 
which was almost destroj^ed. All specimens examined were infested. 

Drepanutremn hoffmani from pond near Isabela, Puerto Rico. Sent by Dr. Wil- 
liam A. Hoffman. Heavily infested with stylet cercariae. 

Austmlorbi.fi glahratus from near San Juan, Puerto Rico. Sent by Dr. Hoffman. 
Various degrees of infestation. 
Subfamily Helisomatinae 

Helisomn anceps, from Unionville. Connecticut. Collected by F. C. Baker. One 
specimen with lung ca\ity filled with rediae and one specimen with cercariae in liver 
and genitalia. 

Helisoma trivolvis lentum, from near Urbana, Peoria, and St. Joseph, Illinois. 
Cercariae in liver and ovotestis. 

Helisoma subcrenatum from Cottonwood Pass, near Gypsum, Colorado. Sent by 
Junius Henderson. Four out of six specimens with cercariae in different parts of the 
body, mostly the li\'er. Some specimens from a sluggish creek one mile west of Devon, 
Montana, collected by J. Henderson and Hugo Rodeck, contained cercariae, mostly in 
the liver. 

Helisoma plexatum, from Teton River, north of Rexburg, Idaho, collected by 
J. Henderson; one out of six infected. 

Helisoma hornii, from Paul Lake, Kamloops District, British Columbia. Sent by 
Dr. D. S. Rawson, Uni^•ersity of Saskatchewan. About one-third were affected by 
cercariae. 

Helisoma pilsbryi from Chetek Lake, Barron Co., Wisconsin. Collected by 
F. C. Baker. Cercariae in eight specimens with the liver and ovote.stis mo.stly 
affected.. 

Helisoma corpulentum from Miles Bay, Lake of the Woods, Canada, Fall Lake, 
Ontario, Canada, and Knife Lake, St. Louis Co., Minnesota. Collected by Dr. 
A. R. Cahn. Many infested with cercariae. 

Heli^soma eorpulcntum multicostatum, from Lake Kahnipiminanikok, Ontario, 
Canada. Collected by Dr. A. R. Cahn. One out of six with cercariae. 

H(lisoma ivhiteavesi from Kashabowie Lake, Ontario, Canada. Collected by 
Dr. Cahn. One out of four infested with cercariae. 

Helisoma campanulatum wisconsinense from Pirate Island, Lake Nipissing, On- 
tario, Canada. From the Biological Boaixi of Canada. One out of five specimens with 
cercariae. 

Subfamily Planorbulinae 

Menelus cooperi callioglyptus from Quatana, Vancouver Island, British Co- 
lumbia. Received from Dr. W. A. Clemens. Two-thirds of the specimens examined 
(about a dozen) were infested with cercariae, in several examples almost consuming 
the liver, albumen gland, and ovotestis. In several specimens the cercariae were 
most numerous about the stomach. Several hundred were observed in some siJecimens. 

Ml 111 tux cooperi from small lakes on Mt. Con.stitution, Orcas Island, Puget 
Sound, Washington. Collected by Dr. Dale Foster. Of fifteen specimens examined, 
one contained cercariae. 

Meuetas dilutatus from L'nionville, Connecticut, fourteen miles west of Hartford. 
Collected by F. C. Baker. One specimen in sixteen contained cercariae. 



24 The MoUuscan Family Planorhidae 

Menettis sampsoni from slough of Meramec River east of Stanton, Franklin Co., 
Missouri. Collected by Leslie Hubricht. Twelve out of fourteen specimens were in- 
fested with cercariae, the liver and genitalia being principally affected. In several 
specimens nearly all of the internal organs had been destroyed. 

Same species from small lake near Hutchins, Dallas Co., Texas, collected by 
Dr. E. P. Cheatum. Fifty per cent of specimens examined were affected by cercariae. 

Promenetus exacuous from small lake in Wainwright Park, Alberta, Canada. Re- 
ceived from A. LaRocque, Canadian National Museum, Ottawa. Nearly all specimens 
examined were infested with cercariae, some in the fore part of the bod}', many about 
the stomach, but mostly confined to the liver and genitalia. Specimens of exacuous 
from Maine, Wisconsin, Michigan, New York, and Ontario did not contain larval 
worms. 

It is unfortunate that parasitological assistance was not available when 
these anatomical studies were in progress in order that the particular 
species of parasitic trematode worms involved might have been ascertained. 
Many species of cercariae remain to be discovered from the tissues of 
planorbid and other fresh-water mollusks. 

The effect of fluke infestation on the anatomy of the snail is variable. 
The cercariae may infest only the liver, in which case, often, the cercariae 
finally leave the snail which recovers from the damage inflicted by the 
parasite. In many other cases, however, the liver, genitalia, and stomach 
are affected and in large measure destroyed. Specimens have been examined 
in which the genitalia were completely destroyed or the genitalia and liver 
obliterated. In one case (Menetus cooperi) , almost the whole snail was 
so filled with cercariae (several thousand) that the normal organization 
could not be distinguished, the cercariae being packed in the space occu- 
pied by the organs and in aggregation taking their form. This was par- 
ticularly true of the genitalia. Faust ( 1920, p. 79) has given a good 
account of the pathological changes in the gastropod liver due to fluke 
infestation. Wesenberg-Lund (1934) and ]\Iiriam Rothschild (1936) have 
recorded instances of gigantism in snails apparently attributable to trema- 
tode infections. 

Several parasitologists have essayed the role of conchologists in an 
endeavor to understand the specific limitations of the groups of molluscan 
species acting as hosts for i^arasitic trematode worms. Among these are 
the late Dr. Adolpho Lutz (1918) of the Instituto Oswaldo Cruz and Dr. 
A. Vianna Martins (1938) of the Laboratorio do Instituto Biologico 
Ezequiel Dias. Dr. Lutz describes all species under the common generic 
name Planorbis, the modern genera Australorbis and Tropicorbis being the 
principal groups discussed. In the main, the work of Dr. Lutz is good and 
the species have been carefully distinguished. The work of Dr. Martins is 
a study of the genus Australoi'bis of Pilsbry, based in part on the earlier 
work of Dr. Lutz. Unfortunately the two genera Tropicorbis and Austra- 
lorbis have been confused by this author and many species lumped under 
Australorbis, to which they have little relation anatomically. It is obvious 
that specific identifications must be accurately made if any value is to be 
attached to these forms as intermediate hosts of parasitic worms. 

In Part II of this work the recognized species, and also the synonyms, 
of species of both Australorbis and Tropicorbis, as well as of other groups, 
will be discussed and the species figured.* 

*The author's death came before he could finish Part II. However, 60 plates made 
for Part II are printed as an Appendix to this work (see page 213 et seq.). H.E.C. 



III. 

NIDIFICATION AND EMBRYOLOGICAL 
DEVELOPMENT 

THE EARLY STAGES of cell growth and development in the phi- 
norbids {Hclisonia trivolvis) have been well described and figured bv 
Holmes (1900, pp. 369-458). Crabb (1927, pp. 67-108) has described 
and figured the early stages of Lijmnaca stagnalis appressa ( =jugi(laris) 
and Lankester (1874) has given us the full development of the European 
Lymnaea stagnalis. More recently (1934) Lowrance has very fully de- 
scribed the early development of Stagjiicola kingi. Little work has been 
done, however, on the embryonic development of the different species of 
the family Planorbidae and especially on their nidification, period of 
development, and the time element in the growth of the voung animal in 
its shell.* 

A dozen or more aciuaria were operated during the years 1930 to 1934 
and careful data were gathered concerning the period of egg deposition, 
number of capsules laid, changes taking place within the egg capsule, and 
growth of the young snails within the egg and after hatching. 

A. DEVELOPMENT OF Helisoma scalare (JAY) 

In 1932, Dr. E. A. Andrews, of the Johns Hopkins University, sent the 
writer a piece of pond lily leaf upon which was a large egg capsvde of 
Helisoma (Seminolina) scalare (Jay), containing twenty-eight eggs in vari- 
ous stages of development. This capsule was deposited in an aquarium but 
the parent came from Lake Butler, Florida. This egg capsule was observed 
as opi^iortunity afforded until all of the embryos were hatched or had died. 
From this capsule a fairly good idea of the development of this planorbid 
was obtained. Observations began when the specimen was received on 
March 2 and the last specimen was hatched on March 17. The different 
stages are figured on plate 51 and are described in the explanation of 
that plate. 

Development was observed to be sporadic in many of the eggs. There 
were resting stages between periods of great activity of rotation about the 
interior of the egg, the rotation beginning in this species the latter j^art of 
the gastrula stage, the second day of development, and becoming marked 
from the early trochophore stage. This rotation is caused by the vibration 
of the numerous cilia attached to the foot of the embryo (CL in figures). 

Observations on the egg capsule began on March 2, when twenty-eight 
fertile eggs were counted. The observations, made several times a day, 
showed the following degrees of development : 

March 2-3. 24 eg^cs in segmentation stages. 4 in early trochophore stage. 

4. Same condition as on March 3. 

5. 20 eggs in gastrula stage ; 4 in trochophore stage ; 4 in preveliger stage. 

7. 18 in gastrula stage ; 5 in trochophore stage ; 3 in veliger stage ; 2 postveliger. 

8. 18 in gastrula stage ; 4 trochophore ; 3 ^'eliger ; 3 embryos with shell. 

*After this manuscript was in press, a very significant experimental study, b.v 
H. B. Roney, on the development of Helisoma eggs, under controlled conditions, 
appeared in Ecology, v. 24, pp. 218-243.— H.J. V-C. 

25 



26 The MoUuscan Family Planorhidae 

March 10. 18 in gastrula stage ; 4 trochophore ; 3 veliger ; 3 embryos with shelL 

11. 18 in gastrula stage ; 4 vehger ; 3 postvehger; 3 embryos with shelL 

12. 18 in gastrula stage; 3 vehger; 4 postvehger; 3 embryos with shelh 

13. 18 in gastrula stage; 3 veliger; 3 postvehger; 3 embryos with shell ; 1 hatched. 

14. 18 in gastrula stage; 3 veliger; 3 postvehger; 2 embryos with shell; 1 hatched. 

15. 18 in gastrula stage ; 2 veliger ; 2 postvehger ; 2 embryos with shell ; 2 hatched. 

16. 18 in gastrula stage ; 2 postvehger ; 3 embryos with shell ; 1 hatched. 

17. All hatched or dead, many of the gastrula stage filled with Protozoa. 

In the above table it will be observed that only ten embryos completed 
their development. Eighteen embryos did not continue their growth after 
reaching the gastrula stage, for what reason is not apparent. In the stage 
shown in fig. 9 on plate 51 the snail is very active, moving about in the 
egg and grazing like the adult snail. The radula can be seen working with 
its peculiar lapping motion, the heart is beating regularly, and the pul- 
monary siphon is functioning, for it can be seen to emit bubbles. One 
young snail four days out of the egg was transferred to an aquarium. This 
specimen was very active, crawling about the glass sides of the jar. The 
eyes were black and very conspicuous. 

Several of the embryos that completed their development showed the 
following history. 

EGG NUMBER 1 

March 2-3. Segmentation and gastrula. March 10. Embrvo stage. Like fig. 10. 
Like fig. 2, 3. 11. Embryo stage. Like fig. 10. 

4. Early trochophore stage. 12. Embryo stage. Like fig. 11. 

5. Trochoiihore stage. 13. Young snail. Like fig. 12. 

7. Posttrochophore stage. 14. Young snail. Like fig. 12. 

Like figs. 4, 5. 15. Young snail. Like fig. 12. 

8. Veliger stage. Like figs. 6, 7. 16. Hatched from egg. Like fig. 13. 

9. Veliger stage. Like fig. 9. 

EGG NUMBER 8 

March 2-4. Early segmentation and ga.s- March 10. Veliger stage. Like fig. 9. 

trula stages. Like figs. 2, 3. 11. Embryo stage. Like fig. 10. 

5. Po-sttrochophore stage. 12. Embryo stage. Like fig. 10. 

Like figs. 4, 5. 13. Young snail. Like fig. 12. 

7. Veliger stage. Like fig. 6. 14. Young snail. Like fig. 13. 

8. Veliger stage. Like fig. 6. 15. Young snail. Like fig. 13. 

9. Veliger stage. Like figs. 7, 8. 16. Hatched. Like figs. 13, 14. 

Both of the above embryos completed their development in fifteen days. 
Probably some early cell divisions took place the day before observations 
began, which would increase the development period to sixteen days. The 
temperature of the room was 70-75 degrees Fahrenheit. The other eggs in 
this capsule showed approximately the same development. The embryo in 
egg number 5 migrated to egg number 6 at the late embryo stage and 
both embryos occupied the same chamber until they were hatched, three 
days later. 

Several adult Helisoma scalare received from Dr. Andrews, collected in 
Lake Butler, Florida, were placed in an aquarium where they bred and 
laid eggs which successfully completed their development. Eggs were first 
observed on Alarch 13 (see plate 52, fig. 1). The egg capsules were de- 
posited on the glass sides of the aquarium and were numbered so that 
development could be easily and accurately observed. Thirteen egg cap- 
sules were deposited early in Alarch: 



Xidification and Emhryological Development 27 

Xo. 1. lOeggs, cap,'*ule3.5by2.5 mm. Xo. 8. 11 eggs, capsule 4.5 by 3.5 mm. 

2. 6 eggs, capsule 3.5 by 2.5 mm. 9. 2 eggs, capsule 4.5 by 2.5 mm. 

3. 8 eggs, capsule 3.0 by 3.0 mm. 10. 9 eggs, capsule 5.0 by 3.5 mm. 

4. 10 eggs, capsule 5.0 by 3.0 mm. 11. 5 eggs, capsule 4.5 by 3.5 mm. 

5. 4 eggs, capsule 3.5 by 2.5 mm. 12. 13 eggs, capsule 5.0 by 4.0 mm. 

6. 10 eggs, capsule 4.5 by 3.5 mm. 13 14 eggs, capsule 5.0 by 3.5 mm. 

7. 10 eggs, capsule 5.0 by 3.0 mm. 

Egg capsule No. 3 with eight eggs developed as follows: 
March 13. Freshly deposited capsule. March 22. Embryo with shell of about one 

14. Early segmentation. whorl. 

15. Gastrula stage. 23. Embryo with shell half filling 

16. Gastrula and trochophore egg. 

stages. 24. Embryo with shell three- 

17. Gastrula and trochophore fourths filling egg. 

stages. ■ 25. Embryo with shell almost 

18. Trochophore and preveliger filling egg. 

stages. 26. Embryo with shell filling egg. 

19. Veliger stage. 27. Four efnbrv'os hatched. 

20. Early embryo stage. 28. Last embryo hatched. 

21. Embryo stage. 

The period of development was fifteen days. 

Capsule Xo. 6, with ten eggs, occupied a longer period (18 daj's) in 
hatching. 

Capsule Xo. 8, with eleven eggs, had all embryos hatched in seventeen 
days, from ]March 15 to ]\Iarch 31. Capsule X"o. 11, with five eggs, de- 
veloped and hatched the young snails in thirteen days, from ^Nlarch 15 to 
^Nlarch 27. All other capsules occupied fifteen to eighteen days. The shell 
when the young are hatched measures about 1.0 by 0.7 mm. 

About two weeks later (iVpril 2) six capsules were deposited measuring 
as follows (see plate 52, figs. 2, 3) : 

Capsule 4.5 by 3.0 mm. with 10 eggs. Capsule 5.0 by 3.0 mm. with 9 eggs. 

Capsule 5.5 by 3.0 mm. with 7 eggs. Capsule 5.0 by 3.0 mm. with 19 eggs. 

Capsule 6.0 by 4.0 mm. with 14 eggs. Capsule 5.0 by 3.0 mm. with 9 eggs. 

One capsule with nine eggs developed as follows, the process occupying 
but twelve days : 

April 2. Freshly deposited eggs. April 8. Post^•eliger and earlj' embrj'O 

3. Segmentation. stages. 

4. Segmentation and gastrula 9. Embryo with .small shell. 

stages. 10. Embryo filling egg. 

5. Gastrula and trochophore stages. 11. Embryo filling egg. 

6. Posttrochojihore and preveliger 12. Embryos hatching. 

stages. 13. Young snails all hatched. 

7. Preveliger and veliger stages. 

On ^May 22 the aquarium was examined for its entire contents. There 
were ninety-six young snails of scalare only sixteen of which were living. 
There were three adult specimens measuring 8 to 10 mm. in length. These, 
curiously enough, were in shape more like Helisoma duryi seminole than 
typical scalare. The shells were very wide with broad spire and decided 
umbilicus. The young snails in the aquarium were approximately seven 
and one-half weeks old. A few of these were measured and the number of 
whorls was counted: 

Height 2.0; diameter 2.5 mm. Whorls 2. 

Height 3.0; diameter 3.0 mm. Whorls 2^>. 

Height 2.5; diameter 2.8 mm. Whorls 21/2- 

Height 2.5; diameter 2.8 mm. Whorls 21/4- 



28 The Molluscan Family Planorhidae 

When hatched the shells usually measure 1 mm. in height and 0.7 mm. 
in diameter and have a trifle more than one whorl. The young scalare, 
therefore, had more than doubled in size in less than eight weeks. On 
August 15, after a hot summer, seven specimens remained in the aquarium. 
Five of these measured as follows: 

Height 4.7; diameter 5.0 mm. Whorls 3%. 
Height 4.0; diameter 4.1 mm. Whorls 3. 
Height 5.0; diameter 5.1 mm. Whorls 3. 
Height 6.0; diameter 5.0 mm. Whorls 3%. 
Height 6.0; diameter 6.0 mm. Wliorls 3^2. 

These measurements indicate that the shells had almost trebled in size 
in about twelve weeks, although but one more whorl was added. 

On June 26, during a hot period of weather, two adult snails of this 
species died, leaving one adult, which lived over winter isolated in a small 
aciuarium. On jMarch 5, 1933, several egg capsules were laid by this indi- 
vidual approximately nine months after its isolation. Two empty egg cap- 
sules were observed on the side of the aquarium and twenty-one young 
snails were crawling about. The young shells measured 2 mm. in height and 
2.5 mm. in diameter and had two whorls. All li\'ed from March 5 to May 
21 when three died. On June 25 the last adult died but nine of the young 
remained alive. 

On September 3, 1933, four of the young scalare were living. The young 
snails at this time, about twenty-three weeks old (160 days) measured 5.0 
mm. in height and 4.5 mm. in diameter and had three and one-half whorls. 
Between September 3 and September 17 these young snails formed eighteen 
egg capsules containing the following number of eggs: 6, 11, 13, 9, 10, 5, 7, 
7, 12, 11, 2, 5, 9, 10, 10, 7, 9, 7. Embryos in but two of the capsules com- 
pleted their development. The parent snails of this last brood, it will be 
noted, were the offspring of an isolated adult scalar^e. The young snails 
lived until January, 1934. 

The development of HeUso)}ia scalare is similar in many respects to 
that described by Lankester for Lymnaea stagnalis (1874) and by Lowrance 
(1934) for Stagnicola kingi. There are, of course, differences in the form of 
the embryos as would be expected in two such diverse families. Lowrance 
found that young snails of Stagnicola kingi hatched in from fourteen to 
sixteen days (p. 10) but that with increased temperature (26 degrees 
centigrade) this period was cut to from nine to eleven days. Liimnaea 
stagnalis may require as much as twenty days or more for development. 

B. NIDIFICATION AND DEVELOPMENT 
IN OTHER SPECIES OF Helisoma 

Plates 51 and 52 

Living material belonging to five additional species and races of Helisoma 
was studied in aquaria during the years 1931, 1932, and 1933. The species 
included were: 

Helisoma trivolvis lentum (Say) 

Helisomn trivolvis fallax (Haldeman) 

Helisoma duryi normale Pilsbry 

Helisoma duryi eudiscus Pil.sbry 

Helisoma tenue calijorniense F. C. Baker 



Nidification and Eutbnjological Develojwient 29 

Several species were from different localities and these as well as each race 
were kei)t in separate aciuaria. Observations were made several times each 
day at intervals of three or four hours. Each jar was labeled and the egg 
capsules lettered or numbered as they were deposited by the animals. 
Notes were kept of developments in each capsule. The data which follow 
have been condensed from the original notes. 

The information sought in these studies was to ascertain the time re- 
quired for development and the rate of growth of the shells of the young 
snails during their life in the aquaria. 

[a] Self-fertilization or Autofecundation 

That self-fertilization or autofecundation is possible among the fresh- 
water pulmonates has been suggested by several zoologists during the past 
hundred years or more, but until comparatively recent time few experi- 
ments have been carried on to test the reality of this method of reproduc- 
tion. Colton (1912. \). 173; 1918, p. 48) has shown that Lymnaea, Physa, 
and several groups of Planorbidae {Gyraulus, Menetus) lay fertile eggs 
by this method when isolated. Crabb (1927) has presented elaborate data 
on this subject, and more recently Larambergue (1939) has issued an 
elaborate monograph particularly relating to Bidimis contortus. On pages 
541-543 he ]iresented a list which includes all of the authentic exami)les of 
autofecundation. This list includes all families of Basommatophora as well 
as a few among the Stylommatophora. Crabb (1927) studied Lymnaea 
stagnalis appressa {=jugularis) to determine whether snails kept in strict 
isolation reproduced by self-fertilization or b}' parthenogenesis. His con- 
clusions were that there was no evidence of parthenogenesis in this snail. 

It is to be noted, however, that reproduction by parthenogenesis does 
occur in some groups of snails. Boycott (1919) has asserted that Palude- 
strina jenkinsi develops by this method. ]More recently Van Cleave ( 1937) 
and ]\Iattox (1937, 1938) have shown that the viviparoid snail Campeloma 
rufutn develops solely by parthenogenesis although other species of the 
genus have been found to be bisexual. The reproductive method in Campe- 
loma was observed by morphological and histological studies and there is 
no question concerning the parthenogenetic method of reproduction in 
the species examined. 

Some years ago, Chadwick ( 1903, p. 265) conducted some interesting 
exi)eriments on Planorbis vorte.v, a common English planorbid. On Feb- 
ruary 2, 1901, he isolated an adult specimen in a jar three-fourths filled 
with boiled water, a small quantity of weed was introduced, the rest of 
the jar was filled with pure oxygen and the vessel was perfectly sealed. 
It remained in this condition for eighteen months, or until August, 1902. In 
June, 1902, aften sixteen months of complete isolation, the snail deposited 
some eggs which were hatched in early July, producing twenty-seven young 
snails, many of which were still thriving under these confined conditions 
on December 10, 1902. In evaluating this set of observations, and many 
others along this line, it should be remarked that only those experiments 
in which individual eggs were isolated have any conclusive value in estab- 
lishing the occurrence of self-fertilization. This is especially true when 
forms are considered for which there are no observations as to the length 
of time the spermatozoa remain viable following copulation. 



30 The Molluscan Family Planorhidae 

Crabb states (1927, p. 91) that self-fertilization is the normal method 
of rei^roduction in Lynmaea and other fresli-water pulmonates and that 
cross-fertilization seldom or never occurs. With this general statement the 
writer can not fully concur. It is doubtless true in many cases of reproduc- 
tion during isolation but that it is the chief method among free snails when 
in aggregation in their native environment or even in the laboratory is 
scarcely possible. The writer has observed many species of Lynniaea, 
Physa, and the planorbids in coitu. If the method of reproduction men- 
tioned by Crabb is the chief or possibly the only method, why should the 
male portion of the genitalia be so elaborately developed with prostate and 
the penial complex provided with such diverse accessories in its makeup? 
The spermatheca has been found to contain a spermatophore containing 
sperm which was obviously deposited during copulation. Self-copulation 
probably occurs when a snail is isolated, at least in those species having 
a penial complex of sufficient length to reach the female opening, which is 
the case in many species of the Planorbidae. 

Crabb states that he was unable to raise progeny from isolated Pla- 
norbis trivolvis iHelisoma) , four individuals being carefully reared in iso- 
lation for 377 days without the laying of a single egg capsule. Ten to 
fifteen small empty egg masses were deposited. Even the control culture, 
consisting of two snails, formed no capsules. Lymnaca stagnalis, on the 
contrary, was very prolific. 

My isolated laboratory stock lays about e\-ery third day for a period of about twenty- 
five days, rests a few days, then begins another cycle of laying. This is continued 
throughout the year. Of fifty-four L.s.appressa isolated from the same egg mass, 
seven laid their first eggs fifty-eight days after hatching. However, they do not reach 
their maximum laving capacity until they are about one hundred days old (Crabb, 
p. 73). 

Colton's experiments on Lynmaea {Pseudosuccinea) columella indicated 
that the interval between hatching and egg laying was widely variable 
(1912, ]i. 175). Thirteen isolated individuals had the following interval 
between hatching and egg laying: 32, 26, 35. 49, 58, 92, 50, 50, 56, 57, 63, 
74, and 74 days. Twenty-six days was the shortest interval and ninety-two 
days the longest interval. 

In the family Planorbidae the intervals are much longer, not only of 
the specimens placed in isolation, but for those in aggregation. Helisoma 
scalare laid thirteen egg capsules in early March, 1932. In early April, 
six additional capsules were produced. An isolated individual which lived 
over winter (nine months) without egg laying, deposited two fertile egg 
capsules on March 5, 1933. Between September 3 and September 17 the 
young snails, 160 days old, laid eighteen egg capsules containing from six 
to thirteen eggs in each capsule. 

Specimens of Helisoma trivolvis lentum were placed in aquaria in 1930. 
On February 16, 1931, a capsule was laid, on February 22 four capsules 
were deposited and on March 7 two capsules were laid. No other eggs were 
laid by these specimens which lived until Se]it ember 17, 1933, or a period 
of 943 days. A young specimen from the parent lentum. was isolated Janu- 
ary 16, 1932. It was about 325 days old. Between May 27 and June 9, 
1932, this individual, after inhabiting the aquarium for 132 days, laid 
twenty egg capsules aggregating 325 eggs. On June 20, 1932, the parent 
snail was removed to another aquarium and on June 22 laid two egg cap- 



Nidification and E tnbryological Developinent 31 

siiles and on June 27 deposited two more capsules. These capsules were 
laid fifteen and twenty days after the large laying period in the first 
aquarium. Two-thirds of the eggs laid completed their development. A few 
of the second generation remained alive for about two years but laid no 
egg capsules. 

These examples seem to indicate that the large planorbids do not breed 
as often as do the lynmaeids and are not as available for studies in de- 
velopment as are members of the Lymnaeidae. Just how the smaller species 
of the genera Menetus, Gyraulus, and Tropicorbis would react to such 
investigations is not known.* It is probable that had Crabb kept his Heli- 
soiita trivolvis longer they might ultimately have laid eggs. 

[b] The Development of Helisoma 

The notes that follow describe some of the results of aquarium observa- 
tions on a few of the species of the genus Helisoma. No attempt has been 
made to go into the finer details of embryological development. This has 
been done by Holmes (1900) and others. 

[1] Helisoma trivolvis lentum (Say) 

SoNoral .spcfimoiis of the Ic ntiim race were received in 1930 from Dr. E. C. Faust 
of the Tulane Medical School, New Orleans. They were collected from the canal at 
New Orleans. This city is also Say's original locality for this species. The snails were 
placed in aquaria and kept under observation for several years. On February 16, 1931, 
an egg capsule was observed, apparently freshly laid, with twenty-five eggs. It 
measured 7.5 by 6.0 mm. On February 22 four additional egg capsules were laid, one 
4 by 3.5 mm. with nine eggs, one 7 by 4 mm. with fourteen eggs, one 9 by 4.5 mm. 
with nineteen eggs, and one 10 by 4.5 mm. with twenty-four eggs. On March 7, two 
other egg capsules were observed, one with fifteen eggs and the other with nineteen 
eggs. All eggs were fertile and contained embryos in the early stages of development. 

On September 12, 1931, twenty-five young snails were counted, ranging in diameter 
from 4.5 mm. with two and one-foui'th whorls to 16 mm. with four whorls. On No- 
vember 28, 1931, nineteen specimens were counted ranging in size from 5.5 mm. in 
diameter with three whorls to 14 mm. with four and one-fourth whorls. On January 
16, 1932, the nineteen specimens were again measured, the smallest being 5.5 mm. in 
diameter with three whorls and the largest 14 mm. with four and one-fourth whorls. 
On March 19, 1932, the same number of specimens remained in the aquarium, the 
smallest being 6 mm. in diameter with three and one-fourth whorls and the largest 
14.5 mm. with foiu' and one-fourth whorls. On June 10, 1932, only fourteen specimens 
remained in the aquarium. fi-\"c ha\ing died. The smallest was 6.5 mm. in diameter 
and had three and one-foiu'th whorls and the largest was 12.5 mm. with four whorls. 
August 15, 1932, only six specimens were alive, the smallest 6.5 mm. in diameter and 
the largest 10 mm. in diameter. On October 23 and December 26 the six specimens 
were still alive. Their size had not increased. 

On March 5, 1933, five specimens were living, the largest 10.5 mm. in diameter 
with four whorls. On June 25, 1933, three were li^■ing, the largest being 11 mm. in 
diameter with four and one-foin-th whorls. On September 17, 1933, two specimens 
were living. These two specimens had li^•ed o\er two years in the aquarium. Of the 
original 125 eggs laid in February and March, 1931, only 25 young snails survived 
until September, 1931, and onl.y two snails were alive two and one-half years later. 
Mortality among the young snails appears to be heavy in their earlj' postembry- 
onic life. 



*Rearing methods for securing uninfected snails to be used in life history studies on 
parasitic worms have been practiced in many parasitological laboratories. W. H. Krull 
(1931) has published the jjrocedure for successful rearing of Gyrauliis parvus and 
found that this species may be reared to full size in from four to five weeks under 
laboratory conditions (Occas. Pap. Mus. Zool., Uni. Michigan, No. 226).— H.J.V-C. 



32 The Molluscan Family Planorbidae 

[2] Helisovna trivolvis fallax (Haldeman) 

October 2, 1931, fifteen specimens of tliis race, collectecl near Cambridge, Massa- 
chusetts, were recei\'ed from Dr. Harold A. Rehder, then in Harvard University (now 
x\ssistant Curator of Mollusca, United States National Museum). Egg capsules were 
observed February 6. 1932, one measuring 4.5 by 3.5 mm. and containing six eggs, 
and one 5.6 by 7 mm. with thirteen eggs. Tlie eggs of both capsules passed through 
their development and were hatched by February 12. On February 28 another capsule 
was laid measuring 5.2 by 4 mm., containing ten eggs, but was eaten by Protozoa after 
three days of development. March 4 a capsule was laid measuring 5 by 6 mm. with 
twelve eggs, and on Maich 10 another capsule was laid, 3.5 by 5.5 mm., containing 
eleven eggs. On March 13 a capsule containing nine eggs was observed. On March 19, 
twenty-two young and five adult snails were counted in the aquarium, the young 
ranging in size from 1.8 mm. to 3 mm. in diameter. 

An examination on May 22 revealed seventeen young snails living. All of the 
adult snails were dead. The li\ing young snails measured as follows: 

2 specimens 2.5 mm. in diameter with 2 whoils. 

3 specimens 2.5 mm. in diameter with 2^/4 whorls. 
1 specimen 2.8 mm. in diameter with 2% whorls. 

3 specimens 3 mm. in diameter with 2V2 whorls. 
1 specimen 3.2 mm. in diameter with 2i/{> whorls. 

4 specimens 3.5 mm. in diameter with 3 whorls. 

1 specimen 3.8 mm. in diameter with 3 whorls. 

2 specimens 4 mm. in diameter with 3 whorls. 

On June 26, 1932, the seventeen young fallnx were still alive. On August 15 there 
were fourteen living young snails which measured as follows: 
1 specimen 2 mm. in diameter with 2 whorls. 
1 specimen 3 mm. in diameter with 2 whorls. 

1 specimen 3.5 mm. in diameter with 2i/-> whorls. 

2 specimens 4 mm. in diameter with 2^2 whorls. 

5 specimens 4.5 nun. in diameter with 3 whorls. 
2 specimens 5 mm. in diameter with 3 whorls. 

2 specimens 5 mm. in diameter with 3M whorls. 
On October 23, 1932, only four young jaUax remained living: 

1 specimen 3.5 mm. in diameter with 2^/^ whorls. 

1 specimen 4.5 mm. in diameter with 3 whorls. 

1 specimen 5 mm. in diameter with 3 whorls. 

1 specimen 5 mm. in diameter with 3^4 whorls. 
On March 1, 1933, these four snails were still living and measured as follows: 

1 specimen 4 mm. in diameter with 2^2 whorls. 

1 specimen 5 mm. in diameter with 3 whorls. 

1 specimen 5.2 mm. in diameter with SMi whorls. 

1 specimen 5.5 mm. in diameter with 3^/4 whorls. 
On May 1, 1933, only three living snails remained: 

1 specimen 4.9 nun. in diameter with 3 whorls. 

1 specimen 5.5 mm. in diameter with 31A whorls. 

1 specimen 5.6 mm. in diameter with Sy^ whorls. 
On June 25 one young snail remained which measured 6 mm. in diameter and 
had three and one-half whorls. 

This small subspecies of HeUsoma trivolvis lived in the aquarium 495 days or 
about seventeen months. It grew from a size of 1.5 mm. in diameter when hatched to 
6 mm. when it died, and increased from one and one-fourth to three and one-half 
whorls. Adult fallax measures 15 mm. in diameter and has five full whorls. The last 
remaining young was, therefore, somewhat more than one-third grown. Full maturity 
would i^robably have been attained the third year after hatching. 

Conclusions of this sort, in which length of life span is estimated from growth 
rates in aquaria, are only tentative and are possibly subject to considerable error. 
Very early experiments on snail development tended to show that the size of reared 
snails is influenced by the volume of the water and the container in which they grew. 
Conclusive evidence of rate of growth in natvu-e could be determined by measuring 
representative samples, from normal habitats, taken periodically as practiced by Van 
Cleave (1932) and his students in the interpretation of life history data. 



Nidificatio)} (Did Eiiibnjological Development 33 

[3] HeXisoma duryi noymalt Pilsbry 

Specimens of this planorbid, collected on the Tamianii Trail, forty miles west of 
Miami, Florida, were sent to the writer by Mr. W. F. Shay of the Department of 
Science, Normandy High School, St. Louis. They were placed in aciuaria in January, 
1931. On January 31 several egg capsules were observed, one containing fifteen em- 
bryos in various stages of development, three in veliger stage and twelve with well- 
formed shells. B.y February 2, eleven snails had been hatched and were crawling on 
the glass sides of the aquarium. By February 6 most of the veliger larvae had been 
hatched. Another capsule contained fifteen eggs with one veliger stage, one gastrula 
stage and thirteen embryos with well-formed shells. These latter hatched on Feb- 
ruary 4. Another capsule contained ten eggs, five embryos with partly formed shells 
and fi\e embryos with fully formed shells. These were hatched by February 5. 

On September 1, 1931, three capsules were observed on the side of the aquarium, 
one with nine eggs, 7 by 4.5 mm. in area, one with ten eggs, 6 by 5 mm. and one with 
eight eggs, 5.7 by 3.2 mm. On September 12, two additional capsules were deposited, 
one with seven eggs (6 by 3.2 mm. in area) and one with four eggs (4.7 by 2.7 mm.). 
Of the first series of three capsules, two died and were eaten by Protozoa and one 
completed its development. Of the second set, one capsule carried out its full de- 
velopment. In this capsule, the veliger stage was reached on September 15 and the 
embryo with a well-formed shell on September 19. On September 20, the four snails 
were actively feeding in the egg capsule, the walls of the egg capsules were broken, 
and the snails were crawling about in the broken interior. On September 21, the snails 
had left the egg capsule and were feeding on the side of the aquarium. It is probable 
that this capsule had been laid for a day or two before first observed because the 
interval of nine or ten days seems too short for comjilete development. 

On January 17, 1932, a recently laid capsule containing sixteen eggs was discovered 
and was obser\ed until all of the embryos had been hatched (see plate 42, fig. 12). 
In this cajisule fifteen days elapsed between early segmentation and exit from the egg. 
By the middle of February the young snails measiu'ed 1.1 by 1 mm. and actively 
glided about the aquarium. The body in the shell is pinkish, the foot hyaline, slightly 
yellowish, the liver brownish, and the eyes black and prominent. The tentacles are 
long and mobile. The radula can be plainly seen at work and the jaw appears blackish 
through the translucent head. 

From the aboA'e capsule and from several others hatched at about the same time, 
forty young snails were released in February. Observations were made on the shells 
several times in March and April. On May 22 there were seven living snails and 
thirty-three empty shells, indicating that mortality had been heavy, principally during 
the month of May. The seven living snails had the following shell measurements: 
1 specimen 1.5 mm. in diameter with 2 whorls. 
1 specimen 2.5 mm. in diameter with 2^-2 whorls. 
1 specimen 2.8 mm. in diameter with 3 whorls. 

1 specimen 3.4 mm. in diameter with 2->4 whorls. 

2 specimens 3.5 mm. in diameter with 3 whorls. 

1 specimen 4 mm. in diameter with 3% whorls. 

On June 26 the seven snails were still alive. By August 15 one had died. The six 
snails gave the following measurements: 

2 specimens 4 mm. in diameter with 3 whorls. 

2 specimens 4.5 mm. in diameter with ZYi whorls. 

1 specimen 5 mm. in diameter with 3^4 whorls. 

1 specimen 5.5 mm. in diameter with 3^/4 whorls. 

On December 26, 1932, but four snails remained alive. These showed the meas- 

vu'ements below: , • . • i- , vu o u i 

1 specimen 4 mm. m diameter with 3 whorls. 

1 specimen 5 mm. in diameter with 3^/4 whorls. 

1 specimen 5.2 mm. in diameter with 3'!4 whorls. 

1 specimen 6 mm. in diameter with 3^/i> whorls. 

On March 12, 1933, three snails were living which mea.sured as follows: 

1 specimen 4.8 mm. in diameter with 3 whorls. 

1 specimen 5.7 mm. in diameter with 3Vi whorls. 

1 s])eciinen 6.1 mm. in diameter with 3Vi! whorls. 



34 The Molluscan Family Plaiwrbidae 

On June 25, 1933, the same three snails showed some growth: 

1 specimen 5.5 mm. in diameter with 3% whorls. 

1 specimen 6.5 mm. in diameter with 3^/i> whorls. 

1 specimen 6.5 mm. in diameter with S^/v; whorls. 
On August 6, 1933, but two snails remained alive. These measured: 

1 specimen 6 mm. in diameter with 3^2 whorls. 

1 specimen 6.8 mm. in diameter with 3^-2 whoi-ls. 
These 3^oung snails li^•ed 570 to 580 days after hatching and increased in diameter 
from 1.1 mm. to 6.8 mm. and in number of whorls from one to three and a half. An 
adult nor male measures about 20 mm. in diameter and has five whorls, so that the 
young snails were about one-thiixl grown after a development period of one year and 
seven months. If this growth is normal, it must require three or four years for this 
race to attain maturity, unless there is considerable acceleration in growth during the 
second or third years. The tem])erature in which the young snails were reared was 
ordinary room heat between 70 and 75 degrees F. This temperature reached 90 degrees 
or more in the hot .summer months. The matter of food is also important since only 
filamentous algae were jilaccd in the aquaria, the snails feeding mostly, howe\er, on 
the green algal deposit which formed on the glass sides of the aquaria. 

[4} HeXisoma duryi ^udiscus Pilsbry 

Si>ccimens of this race of duryi were received from Mr. T. Van Hyning, of the 
Florida State Museum, collected at Silver Springs, Marion County. They were re- 
ceived at the laboratory on October 2, 1931. On December 13 an egg capsule was laid 
measuring 2 by 2.5 mm. in area with five eggs. On February 6, 1932, another capsule 
was laid measuring 2 by 4 nmi. with nine eggs, and on February 12 a capsule with 
seven eggs. On February 10 a large capsule measuring 5 by 4 mm. was deposited 
containing twelve eggs. One capsule (Feb. 10) developed to the gastrula stage and 
then ceased growth. Another was disintegrated and the space was filled by Protozoa. 
A third capsule (Feb. 12) completed its development, all of the embryos being 
hatched. 

A single adult cudisciLS was left in the aquarium and on June 11, 119 days after 
the laying of the last egg capsules, egg laying began again with the deposition of a 
capsule measuring 4 b.v 3.5 mm. and containing two eggs, each egg 1 mm. in diameter. 
On Jime 13 the eggs had reached the gastrula stage. From June 14 to June 26 the eggs 
remained in the same stage and at the last date the eggs appeared to disintegrate. 

[5] HeXisotna tenue. cali^oyr\,i&ns& F. C. Baker 

Specimens of this race were recei\ed from Dr. S. S. Berry, collected from Prospect 
Park, near Redlands, San Bernardino Mts., California. They were placed in an aquari- 
um on February 12, 1932, and laid nine egg capsules on the next day. The nine 
capsules contained 199 eggs as noted below: 

No. 1. 4 by 4 mm. in diameter containing 15 eggs. 

2. 5 by 3.5 mm. in diameter containing 18 eggs. 

3. 4 by 7 mm. in diameter containing 21 eggs. 

4. 6 by 3.5 mm. in diameter containing 28 eggs. 

5. 4 by 5 nun. in diameter containing 15 eggs. 

6. 4 by 4 mm. in diameter containing 11 eggs. 

7. 4 by 7.5 mm. in diameter containing 27 eggs. 

8. 4.5 by 7 mm. in diameter containing 26 eggs. 

9. 5 by 8 mm. in diameter containing 38 eggs. 

Development was fairl.v regular and occupied fifteen days, from February 13 until 
February 28. A typical development is indicated below: 
Feb. 14. Segmentation begun. Feb. 23. Embryos with shell forming. 

15. Segmentation ancl gastrula stages. 24. Embryos with shell ^3 filling 

16. Gastrula and trochophore stages. membrane. 

17. Trochophore and preveliger 25. Embryos with shell filling % 

stages. and y^ of membrane. 

18. Early veliger stages. 26. Embiyos with shell filling % of 

19. Veliger stages. membrane. 

20. Early embryo stages. 27. Embiyos with shell completely 

21. Early embryo stages. filling membrane. 

22. Embryos with shell forming. 28. All hatched. 



Nidification and Emhnjoloykal Development 35 

On February 15 three cajjsules were laid by the adult snails. They contained 
three, eleven, and thirteen eggs respectively and development occupied thirteen to 
fifteen days, from February 28 until March 12. On February 18 a capsule 9 by 6 mm. 
was laid containing forty eggs, and on February 20 four cap.sules were deposited meas- 
uring 6 by 5, 9 b\' 6, 6 by 5, and 6 by 4.5 mm. They contained thirty-five, thirty-three, 
twenty-eight, and twenty eggs respectively. On March 1 and 2, two capsules were laid 
containing thirty-one and twenty-three eggs. All of these eggs completed their de- 
velopment in from twelve to fourteen da.ys. 

On June 5, 1932, the aquarium was examined and the shells counted and measured. 
There were ninety-six li\ing young snails and forty-fi\e empty shells, 141 specimens 
in all which had hatched from the capsules enumerated above. The living 3'oung snails 
gave the following measurements: 

8 specimens 1.5 mm. in diameter with 1V> whorls. 
18 specimens 2.0 mm. in diameter with 2 whorls. 
3 specimens 2.3 mm. in diameter witli 2 whoi'ls. 
■ 40 specimens 2.5 mm. in diameter with 2 whorls. 
20 specimens 3.0 mm. in diameter with 2 whorls. 
6 specimens 3.0 mm. in diameter with 2^/l> whorls. 
1 specimen 4.0 mm. in diameter with 21-) whorls. 
Between June 5 and June 26, fifty-four young snails died, leaving fort3'-two 
active young and three adult .snails. On August 15, only fourteen young snails 
were alive, the great mortality being largely due to the very hot summer. The 
measurements of these survivors are shown below: 

1 specimen 2.1 mm. in diameter with 2 whorls. 

2 specimens 2.5 mm. in diameter with 2 whorls. 

3 specimens 3.0 mm. in diameter with 2i/-i w'horls. 
6 specimens 3.5 mm. in diameter with 2V-> whorls. 

2 specimens 4.0 mm. in diameter with 2% whorls. 

On October 23. 1932, two young snails died leaving twelve active 3'oung. On 
December 28, 1932, four additional snails died lea\ing eight young which gave 
the following measurements : 

1 specimen 3.5 mm. in diameter with 2V2 whorls. 

1 specimen 4.0 mm. in diameter with 2y-2 whorls. 

1 .specimen 4.0 mm. in diameter with 3 whorls. 

1 specimen 4.2 mm. in diameter with 3 whorls. 

3 specimens 4.5 mm. in diameter with 3 whorls. 
1 specimen 4.9 mm. in diameter with 3 whorls. 

On March 12, 1933, only five young .snails remained alive, as noted below: 
1 specimen 4.0 mm. in diameter with 21^ whorls. 

1 specimen 3.5 mm. in diameter with 3 whorls. 

2 sjjecimens 5.0 mm. in diameter with 3 whorls. 
1 specimen 5.0 mm. in diameter with 314 whorls. 

On May 1, 1933, but two specimens remamed alive. mea.suring: 
1 specimen 4.0 mm. in diameter with 3 whorls. 
1 specimen 5.2 mm. in diameter with 3^/4 whorls. 

On June 25, 1933, one specimen only remained, mea.suring 6.1 mm. in diameter 
with three and one-half whorls. This specimen had li\ed from February 28. 1932, until 
June 25. 1933, an interval of 482 days or sixteen months. It had grown from a diameter 
of 0.8 mm. to 6.1 mm. and the whorls increased from one to three and one-half. Adult 
californiense measures 20 nmi. in diameter and has five whorls which would indicate 
that the young specimen sixteen months old had made about one-third of its growth. 
As in the cases of the other species described in this chapter, factors of volume of 
water, food, and temperature maj^ have retarded the normal growth of the young of 
this race. At this ratio full maturity would be attained between the third and fourth 
years of life. 

[6] Other Records of Egg Laying 

HcUfiODUi pilshryi infracnrinatiun F. C. Baker. Sjiecimens of this species were re- 
ceived from Mr. A. LaRocque, of the Canadian National Mu.sevmi. They were collected 
in the Rideau River near Ottawa. Canada. On June 20 two egg cap.sules were deposited 
each measuring 6 by 4.5 mm. in size and containing eighteen and twenty eggs. On 



36 The Molluscan Family Planorhidae 

May 7 a capsule was laid which measured 7 by 4.5 mm. in area and contained twenty- 
two eggs. Development was not obser\ed. 

Hclisoma traskii (Lea). Six shells of this species, preserved in alcohol, received 
from Mr. Stanley Siegfus of Bakersfield, California, had eleven egg capsules on the 
shells, containing 394 eggs. A capsule containing fifty eggs is figured (13) on plate 52. 
The specimens were from the Buena Vista Canal, outlet of Kern Lake, California, near 
the type locality for traskii. The capsules and eggs are noted below: 
1 shell with 2 capsules containing 16 and 24 eggs. 
1 shell with 2 capsules containing 45 and 42 eggs. 
1 shell with 1 capsule containing 10 eggs. 
1 shell with 2 capsules containing 35 and 85 eggs. 
1 shell with 3 capsules containing 35. 22. and 20 eggs. 
1 shell with 1 capsule containing 50 eggs. 

Mociuin-Tandon (1855, pp. 425-439) collected egg capsules from water bodies in 
the environs of Toulouse, France, and obser\ed the development of some of the 
embryos. Some of his observations are recorded below : 

Segrnentina nitida (Miiller). Nine egg capsules containing 3, 4, 5, 6, 7, and 8 eggs, 
the capsules measuring 0.25 to 1.5 mm. in diameter. Development occupied ten to 
twelve daj^s. 

Hippeutis jontanus (Lightfoot). Several capsules with 3, 4, 5, and rarely 6 eggs 
in each capsule. 

Gyrorbis co7)iplanatus (Linn.) {^ Planorbis planorbis (Linn.)). Eight capsules 
containing 10, 11, 13, 16, 17, and 21 eggs. 

Gyrorbis carinatus (Beck in Moller) { ^ Plnnorbis cnrinatus). Capsules contain- 
ing ten to twenty eggs each. Development occupied ten to fifteen days. 

Gyrorbis vortex (Linn.) {^^ Anisus vortex (Linn.) ). Ten to twelve eggs in a cap- 
sule which were 4 mm. in diameter. Development required ten to twelve days. 

Plnnorbis albus Miiller {^ Gyraulus albus (Miiller)). Capsules 3 to 4 mm. in 
diameter containing four to ten eggs. 

Planorbis contortus Linn. {= Bathyomphahis contort us (Linn.) ). Capsules 3 mm. 
in diameter containing six to eight eggs. Development occupied ten to twelve days. 

Planorbis corneus (Linn.) {^ Planorbarius corneus (Linn.)). Egg capsules 9, 
11, 12, 13, and 15 mm. in diameter containing twelve to forty eggs each. Development 
required fifteen to sixteen days. 

Brooks (1880) has recorded the early stages in the development of the small snail 
Gyrauhis parvus (Say) {= Planorbis parvus Say). 



IV. 

DISTRIBUTION IN TIME 
AND SPACE 

A. GEOLOGICAL HISTORY AND DISTRIBUTION 

THE ANCESTRY of the Planorbidae, as of other members of the 
puhnonate molkisks, is shrouded in mystery. It is said that the 
ancestors of the Planorbidae, as of other groups of the Basom- 
matophora, were originally aquatic, then migrated to the land and finally 
again returned to aquatic habitats. Perhaps this was accomplished through 
such groups as the Auriculidae {Carychium for example) which have the 
Basommatophorous organization but inhabit the land. 

In America the family apparently first appears in the Morrison forma- 
tion which is considered of Jurassic or Early Cretaceous age, probably 
Jurassic. In Europe, a species, Planorbis mendipensis IVIoore, is known 
from the Liassic of England. The family is not uncommon in the Bear 
River formation, believed to be at the top of the Lower Cretaceous 
(Comanchean), or at the base of the Upper Cretaceous, and also in the 
several divisions known to belong to the Upper Cretaceous, as Judith 
River, Belly River, and others. During Tertiary time the family was well 
represented. Eocene, ]\Iiocene, Oligocene, and Pliocene formations have 
yielded many characteristic species. The Pleistocene planorbid fauna is 
practically the same as the recent fauna. 

As the few specimens of planorbid shells from Jurassic or Lower Cre- 
taceous time are not notably different in general characteristics from those 
of later geological periods or from the modern fauna, it is obvious that the 
family in some form must have existed in earlier strata, Triassic and 
Carboniferous (Pennsylvanian and Mississippian) . A Physa (prisca Wol- 
cott) and other fresh-water groups are reported from the Mississippian of 
Nevada and fresh-water and land mollusks are known from various locali- 
ties from strata of Pennsylvanian age. Planorbids, however, have not yet 
been reported from these older geological periods. 

In Europe this family is fairly common in rocks of IMesozoic and 
Cenozoic age, but earlier records are very few in number. A Triassic pla- 
norbid has already been mentioned. In the Upper Oolite another species 
appears, Planorbis fisheri Forbes. In the Eocene a number of species of 
this family occur, and in the Oligocene more than eleven species are 
known. The family is not uncommon in later periods. On the continent a 
large number of species and races of this family have been recorded from 
nearly all of the later geological periods. Wenz (1923) has listed all of 
these but many of the species have obviously been placed in the wrong 
genera, especially some of the large forms which are listed under the genus 
Planorbina , for it does not occur in Euroi^e. It is cjuite probable that these 
large species are members of the genus Planorbarius and are related to 
the large Planorbarius corneus so common in the recent fauna. 

In America (see Henderson, 1935) sixty-three species of fossil planor- 
bids have been described. Of these two are of Jurassic or Comanchean age, 



37 



38 The Molluscan Family Plaiwrbidae 

two from Comanchean, five from Upper Cretaceous, eight from Eocene, 
six from Oligocene, five from Miocene, thirty from Pliocene, and five 
simply described as 'Tertiary.' 

It is obviously very difficult to place fossil mollusks in appropriate 
genera in a classification based on anatomical characteristics. Nearly all 
of the fossil planorbids of America and Europe have been described as 
'Planorhis.' With the greatest of care it is possible to place some of these 
species in their correct genera as understood at the present time. Some 
forms, however, can only be tentatively i^laced, basing the decision on the 
similarity of the fossil species to some known living species of which the 
anatomy is known. Even among modern species tliis method is fraught 
with danger because of similar resemblances of the shells of several genera, 
as in Planorbula and Tropicorbis, where some species of the latter genus 
have internal lamellae in the aperture similar to species of the genus 
Planorbula. The two genera are far ai^art anatomically. 

Among American fossils the following genera are known to be repre- 
sented by several species and races: 

Tropicorbis, 1 species; Paraplanorbis, 1 species; Platytapkius, 2 species; Gyraulus, 
6 species; Helisonia, 8 species; Carinifex, 2 species; Vorticijex, 8 species; Perrinilla, 
2 species; Parapholyx, 2 species; Pompholopsis, 1 species; Menetus, 5 species; 
Planorbifex, 1 sjjecies. 

Many of the species now known as Planorbis may later be placed in more 
appropriate genera. It is proposed in Part II of this work to review criti- 
cally all of the American fossil Planorbidae, including several from the 
West Indies and Central America, and to endeavor to place each species in 
its correct genus.* 

The geographical distribution of the extinct species of the family Pla- 
norbidae is not very different from that of the recent species of the family. 
Fossil species of the family have been recorded from Europe, Asia, Africa, 
Australia, some of the islands of the Pacific Ocean, North and South 
America, and the islands of the West Indies. 

B. GEOGRAPHICAL DISTRIBUTION 

Like the Lymnaeidae, the Planorbidae are world-wide in their geographic 
distribution. There is scarcely a known region in which some of the pla- 
norbid snails do not live. The distribution by genera, however, is more or 
less limited. Typical Planorbis and Planorbarius are mostly confined to 
Europe and western Asia, wdth possibly some forms of circum-Mediter- 
ranean distribution. Helisoma is wholly American but is known from both 
North and South America and from some of the West Indies. A fossil 
species has been reported from northeast Siberia (Lindholm, 1933). This 
genus is numerous in North America, principally the northern part of the 
United States and Canada. Planorbula is found only in eastern North 
America from Alabama northward. Carinifex and Parapholyx are west 
American in distribution. Menetus is American and does not extend 
south of the United States. A small group of Helisoma (Seminolina) oc- 
curs only in the peninsula of Florida. 

*As explained elsewhere, Mr. Baker's death prevented him from completing Part II 
of this monograph. 



Distribution in Time and Space 39 

Ai(.str(dorbi.s is known from South America and the West Indies but 
is not found north of the Isthmus of Panama. Tropicorbis occurs in South 
and Central America, in Mexico, the West Indies, and in the southern 
part of the United States bordering the Gulf of Mexico. Curiously enough, 
a closely related group, known as Afroplanorbis, is found in northern and 
central Africa and resembles Tropicorbis so closely, in both shell and 
anatomy, that it is a question whether the two groups are not identical 
generically. Anisus is mostly European and Asiatic. Segmentina is typi- 
cally European, west Asian, and north African. Several groups related to 
Segmentina, as Polypylis, Helicorbis, Pingiella, and Intha, are confined 
to eastern Asia and some of the Pacific islands. Taphius occurs only in 
Central America and in northern South America. Gyraulus is the most 
widely distributed of any of the genera of Planorbidae, being known from 
North America, Europe, Asia, Africa, and some of the islands of the 
Pacific as w-ell as from the West Indies. It is typically a northern group 
(palaearctic) but a few species extend southward into the tropical regions. 

The present study of the distribution of the members of the family 
Planorbidae shows conclusively the value of the anatomy in the classi- 
fication of the species. It is of interest to note that in considering the 
distribution of the genera, details of the anatomy have been the only 
means by which the different groupings could be made with certainty. 
Hence our knowledge of distribution has become more definite and better 
understood than was possible when shell characters were given chief taxo- 
nomic value. The shell alone is not sufficient to distinguish groups because 
there are parallels in growth tendency which render shells of widely sepa- 
rated genera confusingly similar in appearance. Instances of this are found 
in the species of Tropicorbis and Planorbida, Aiistralorbis and Helisonia, 
Segmentina and Polypylis, etc. 

Dispersal of Species 

The presence of species of mollusks in isolated places has been somewhat 
of a puzzle to many zoologists. How, for example, are ponds without inlet 
or outlet and more or less widely separated, populated by one or more 
species of planorbids or other fresh-water species? In what manner have 
the same species of Tropicorbis, Australorbis, or Drepanotrema found 
their way to so many of the islands of the West Indies, isolated by large 
and deep areas of salt water? Examining the distribution of Aiistralorbis, 
for example, we find it occurring in eastern and northern South America 
and also in many of the groups of islands — the Lesser Antilles, the Greater 
Antilles, Puerto Rico, and Jamaica. Some species of Tropicorbis have the 
same distribution. 

Natural dispersal by migration is out of the question. Driftwood might 
answer for land snails (at least to a limited degree) but not for fresh- water 
forms. A former connection with South America occurred too remotely to 
answer satisfactorily the question. When we examine the migration routes 
of the migrating birds, especially the wading birds and ducks, we are 
struck by the similarity of the geographic routes of the birds with the 
geographic distribution of the snails. One route is from Venezuela, South 
America, through the Caribbean and West Indian islands as follows: 
Trinidad, Grenada, St. Vincent, St. Lucia, Martinique, Dominica, Marie 



40 The MoUuscan Family Planorbidae 

Galente, Antigua, St. Christopher, St. Thomas, Puerto Rico, Haiti, Ja- 
maica, and Cuba. The three genera Australorbis, Tropicorbis, and Dre- 
panotrema inhabit most of the islands mentioned. Another route is from 
Venezuela northward up the eastern coast of Panama, close to Costa Rica, 
Nicaragua, Honduras, Guatemala, eastern Mexico to the gulf coast of the 
United States. The genus Tropicorbis has this distribution and many of its 
species are widely distributed. Some migrant birds pass up the west coast 
of Central America and ]\Iexico. 

It is the writer's belief that the populating of many if not all of the 
islands of the West Indies with planorbid and other fresh-water mollusks 
has been brought about through the agency of migrating birds. They stop 
at these islands to feed and rest, the snails become attached to the feet or 
other parts of the bodies of the birds, to be liberated when the birds make 
other stops. Young snails have been found attached to the feet of many 
birds. In the case of the Basommatophorous mollusks a single snail in- 
troduced into a pond would be sufficient to insure population since self- 
fertilization is easily accomplished. By this means in a few years a body 
of water would be a prolific habitat for the species. Aquatic insects, 
especially beetles, would perform the same service, especially in populating 
closely associated ponds or streanis. Young snails have been found attached 
to the wings (elytra) of beetles. 

Natural migration doubtless takes place in connected streams and other 
bodies of water and will account for the dispersal of related species within 
the drainage of a water system. Floods often carry species of snails over 
natural divides. In the distribution and dispersal of the Mollusca, all 
agencies must be taken into account. The scarcity of records of snails on 
the bodies of migrating birds is primarily due to the fact that those who kill 
the birds, sportsmen and hunters, pay no attention to what may be at- 
tached to the feet of their victims. Ornithologists, too, do not carefully ex- 
amine the bodies of the specimens and the snails fall off or are brushed off 
during the preparation of the skin for the cabinet. Careful examination of 
the bodies of birds would doubtless provide many valuable evidences for 
avian dispersal of fresh-water and other mollusks. 



V. 

HISTORICAL SKETCH OF 
CLASSIFICATIONS 

IX THE EARLY VOLU:\IES on the IMollusca, the planorbids, as well 
as other genera, were largely classified by the shells and were placed 
in families with wide limits as to the genera involved. Thus in 1851- 
1856, in S. P. Woodward's Manual of the Mollusca, nearly all of the 
genera of fresh-water pulmonates — Limnaea, Chilina, Physa, Planorbis, 
and Ancylus — appear in the family Limnaeidae. In A History of British 
Mollusca, by Forbes and Hanley, in 1853 (volume iv) the fresh-water 
pulmonates of the genera Limnaea, Planorbis, Physa, and Ancylus are all 
placed in the family Limnaeidae. 

AV. G. Binney, in 1865, published a work on The Land and Fresh-Water 
Shells of North America, in which the fresh-water pulmonates are all 
placed in the family Limnaeidae with Limnaeinae, Planorbinae, and Ancy- 
linae as subfamilies, Physa being included in the subfamily Linmaeinae. 

Li 1870, W. H. Dall proposed a classification in which four subfamilies 
were recognized: Limnaeinae, Planorbinae, Camptocercinae, and Pom- 
pholiginae. In 1872, George W. Tryon, Jr., in a Monograph of the Fresh- 
icater Univalve Mollusca of the United States, placed all groups under 
the family Physidae, but separated the principal groups as subfamilies: 
Limnaeinae, Pompholiginae, ^legasystrophinae, Planorbinae, and An- 
cylinae. In this grouping he was following Haldeman ( 1842-1844) who 
|)laced Planorbis and other groups in the family Physidae. 

Paul Fischer, in the Manuel de Conchyliologic (1883), listed most of 
the fresh-water pulmonates under the family Limnaeidae, within which he 
recognized Ancylinae, Limnaeinae, and Planorbinae as subfamilies. Physa 
he relegated to a separate family. Tryon, a year later (1884), in the third 
volume of his Structural and Systematic Conchology, placed all of the 
fresh-water pulmonates under the family Limnaeidae with subfamilies 
Limnaeinae (including Physa, Aplexa, Bulinus, etc.), Pompholiginae, 
Planorbinae, and Ancylinae. A. H. Cooke, in 1895, evidently following 
Paul Fischer, separated Physidae as a family but places the subfamilies 
Limnaeinae, Planorbinae, and Ancylinae in the Limnaeidae. F. C. Baker 
in 1902 and Dall in 1905 separated Physa and Aplexa to form the family 
Physidae but placed Limnaea [Lymnaea) , Planorbis, and allied genera in 
the family Limnaeidae. Ancylus was made a separate family, Ancylidae, 
by Baker. 

In 1902, Westerlund placed all of the Basommatophorous mollusks in 
the family Limnaeidae with four subfamilies, Limnaeinae, Physinae, 
Planorbinae, and Ancylinae. Dybowski (1903) proposed a classification of 
tlie Basommatophora in which six families were recognized, Limnaeidae, 
Limnophysidae, Amphipeplidae, Planorbidae, Ancylidae, and Physidae. 
Bryant "Walker ( 1918) in his 'Synopsis' recognized four families, Lym- 
naeidae, Planorbidae, Physidae, and Ancylidae. 

From 1920 onward, most of the important monographs and lists have 
accepted the four-family division of the Basommatophora, Lymnaeidae. 
Planorbidae, Physidae, and Ancylidae (Germain. 1921-23; Kennard and 

41 



42 The MoUuscan Family Planorbidae 

Woodward, 1926; Pilsbry and Bequaert, 1927; F. C. Baker, 1928; Haas, 
1929; Lindholm, 1926; thiele, 1931; and others). Germain (1931), in his 
Mollusks of France, recognized five families, the four previously alluded 
to and Bulinidae, the groups of which were thought to constitute a family. 
Many other works might be listed, especially by European writers, as 
Lindholm, Westerlund, Clessin, Dybowski, Odhner, Pallery, Preston, Soos, 
and others. The most important of these are listed in the synonymy under 
the different genera. The large monographs, such as Clessin ( 1886) and 
Sowerby (Reeve, 1872), do not help much in family distinctions and the 
lesser faunal lists of both continents, of which there are many, simply copy 
the classification as published in some of the works mentioned above. 

In the matter of generic distinctions among the planorbids there is 
little of note in the earlier works. In 1884, Tryon listed most of the group 
names as subgenera of Planorbis, recognizing Segmentina as a distinct 
genus. Pompholyx, Carinifex, and Choanomphalus are listed as genera with 
some subgenera, mostly fossil groups. In 1905, Dall considered all groups 
but Segmenti7Ui as subgenera of Planorbis. Germain, 1921, followed Dall. 
Kennard and Woodward (1926) did likewise. In 1926, F. C. Baker recog- 
nized the groups Helisoma, Planorbula, Menetus, and Gyraulus as being of 
generic rank and in 1928 fully described these groups, giving anatomical 
reasons for their distinction. Among European works, Lindholm in 1926 
recognized as of generic rank Planorbis, Tropidiscus, Spiralina, Anisus, 
Gyraulus, Bathyomphalus, Armiger, Hippeutis, and Segmentina, a great 
step in advancement over previous works as regards classification. Thiele 
in his Handbuch (1931) was too conservative, listing all groups as sections 
under the genera Planorbis and Anisus. Mori (1938) in his classification 
of Japanese Planorbidae followed Thiele. It is to be observed, however, 
that all of these genera or subgenera as treated by early authors, were 
diagnosed from shell characters for the most part. 

In a review of the classifications of the Basommatophorous grouji the 
change in number of families and genera recognized is noteworthy. From 
one family in 1870 (Limnaeidae or Physidae) this grouping has grown 
to five at the present time, indicating a tendency to recognize smaller 
group differences and also indicating advance in knowledge concerning 
these groups. Many generic and subgeneric names have been proposed 
during the past ninety or one hundred years but these were founded almost 
wholly on shell characteristics. No such analytical studies as those on 
the land mollusks by H. A. Pilsbrv and bv H. B. Baker were made until 
after the year 1920. 

Studies of the anatomy of the Planorbidae began in Europe many years 
ago but were confined to only a few species. ]\Iost of the early papers or 
works on anatomy simply gave as illustration a familiar example, as, 
for example, Planorbis corneus and Limnaea stagnalis figured by Moquin- 
Tandon in 1855. Baudelot (1863) published good figures of the genitalia 
and other organs of Planorbis corneus {= Planorbarius) . In 1867, Ficinus, 
an almost forgotten WTiter, published an article on the penis of Planorbidae 
in which he divided the European species of Planorbis into two groups, 
(1) with a penial stylet, including Planorbis vortex, leucostoma, spirorbis, 
albus, and contortus, and (2) without a stylet, including Planorbis corneus, 
nitidus, and Jontanus. He erected the genus Appendicularia for Planorbis 



Historical SkelcJ) oj Classifications 43 

7iiti(lu.s and F. fontdnus because of the presence of the flagella on the penis. 
This is, as far as known to the writer, the first attempt to chissify the 
Planorbidae by reference to details of the anatomy. 

In 1891, Buchner pubHshed the first comprehensive account of the 
genitalia of the family Planorbidae. He divided the male organ into four 
types, (1) corneus with a small penis, (2) nitidus and cotnplanatus with 
flagella and sperm outlet at the side, (3) marginatus and carinatus with 
sperm outlet in the center, and (4) contortus, vortex, rotundatus, and albus 
with a stylet. He did not distinguish the peculiar gland of corneus from 
the penis. The difference between the prostate diverticula of Planorbis 
corneus and the smaller species, vortex, carinatus, nitidus, etc., w'as espe- 
cially mentioned but no reference was made of the presence of a separate 
prostate duct. There was a good account of the excretory organ (kidney). 
Simroth's account (1912) of the genitalia of the Planorbidae was based on 
Buchner's work and added nothing to our knowledge of the antomy of the 
group. 

In 1917, L. Soos published a paper on the anatomy of the Hungarian 
Planorbidae, giving figures of the genitalia of Planorbis corneus, Tropidis- 
cus planorbis, Segmentina nitida, Bathyomphalus contortus, Gyrorbis 
spirorbis, and Gyraulus albus. The radulae and the digestive system were 
also considered. This is the best work on the anatomy of the Planorbidae 
which had appeared up to this time. 

During the decade from 1921 to 1930, several notable papers appeared 
on the anatomy of the family. Annandale (1922) and Annandale and 
Prashad (1919-1921) added to our knowledge of the anatomy of the 
Indian Planorbidae. In 1923, Rao published an exhaustive treatise on the 
anatomy of Annandale's new genus Indoplanorbis. Connolly (1925) figured 
the genitalia and radula of Planorbis pfeiffen which indicated that it was 
related to the West Indian genus Tropicorbis. F. C. Baker, in 1926, pub- 
lished notes on the genitalia, jaws, and radulae of certain American 
Planorbidae and in 1928 (AIolI. of Wis., I, pp. 306-387) presented descrip- 
tions and figures of the genitalia, jaws, and radulae of the species of Pla- 
norbidae inhabiting the Middle West. The subfamily Helisominae (Heli- 
somatinae) was proposed as new on page 309 of that work. The classifica- 
tion of the genitalia is based on that of Buchner with the addition of two 
types, one new and one following Annandale. 

In 1929, Odhner published an account of the Alollusca of the Tiikerns 
in which the genera were separated by characteristics of the genitalia, 
radulae, and other anatomical features. On page 22 a key appeared in 
which the groups were briefly diagnosed from the anatomical standi)oint. 
This was the most modern treatment which the family had received and the 
key is the first attempt to separate the genera by the use of anatomical 
differences. 

During the decade 1931 to 1940, several critical papers appeared on 
the anatomy of the Planorbidae, adding greatly to our knowledge and 
clearing up many doubtful jioints in the classification based on the anato- 
my. In 1931, Germain issued his work on the land and fresh-water mol- 
lusks of France in which outline figures of the genitalia, and some of the 
radulae, were given. No attempt was made, however, to base a classifica- 
tion on the anatomical data. Also in 1931, appeared F. C. Baker's paper 



44 The Molluscan Family Planorbidae 

on the classification of the larger planorbes of Europe and America, in 
which Planorbis corneus and the American Helisoma species were discussed 
and the genitalia and radulae figured. The peculiar penial gland of the 
genus Helisoma was discussed at length. The same author, in 1933, made a 
study of the peculiar genitalia of Indoplanorbis exustus of India adding 
some features to the previous paper by Rao. Later, the same author pub- 
lished short papers placing certain disputed species in their proper generic 
position, based on their anatomy. Thus, in 1935, Planorbis wmbilicatellus, 
long thought to be a Gyraulus, was shown to be a member of the genus 
Menetus and a new subgenus was proposed for Menetus exacuous 
(Promenetus) . In 1936, Planorbis obstructus was shown to belong in the 
genus Tropicorbis and the true relationship of Parapholyx was indicated. 

In 1935, A. Soos published a paper on the Planorbidae of Hungary 
which included good figures of the genitalia of the species inhabiting that 
country. In 1934, a paper from the pen of H. A. Pilsbry discussed the 
planorbid fauna of Florida, their genitalia were figured, and a new name 
{Sem.inolina) was proposed for the group which is not found outside of the 
Florida peninsula. The classification of other groups, Tropicorbis, Menetus, 
Carinifex, and Parapholyx was .discussed and a new genus Australorbis 
was proposed for the large snails inhabiting South America and the West 
Indies. The European genus Anisus was ably discussed. A new subfamily, 
Planorbulinae, was established. Characteristic keys to the genera of 
American Planorbidae were given, based on anatomical features. It is not 
overstating to say that this paper is the most comprehensive account of 
the family Planorbidae from a modern standpoint that has yet appeared. 

From the foregoing summary it is plainly obvious that a detailed study 
of the classification of the family Planorbidae, based on anatomical in- 
formation, comparable to the methods used by Pilsbry on the land mol- 
lusks, is still to be prepared. An attempt to supply this deficiency is the 
purpose of the present work. It is believed that a foundation has been laid 
upon which to build a natural classification of the fanfily Planorbidae. 



VI. 

A NEW CLASSIFICATION OF THE 
FAMILY PLANORBIDAE 

GENERAL DISCUSSION 

DURIXG THE PAST FIFTY YEARS, the classification of the land 
shells (Stylommatophora) , under the able leadership of Dr. Henry 
A. Pilsbry, of the Academy of Natural Sciences of Philadelphia, 
has been brought to a high degree of accuracy and completeness. This has 
been accomplished by the study of anatomical details of the genera and 
species, bringing together groups which are allied by features of the natural 
organization of the animal. While the shell has helped in many cases it 
has been the internal features, chiefiy the genitalia, that have given criteria 
for generic and higher distinctions. The results obtained by these studies 
have been accepted by nearly all malacologists and conchologists. 

No such comparable work has been done on the fresh-water pulmonates 
(Basommatophora), and the few attempts to apply anatomical criteria 
for generic distinctions, as used in the Pulmonata, have met with more or 
less criticism. It is obvious, however, that only by the careful study of the 
internal organs of the animal can a natural classification be secured. This 
was attempted by the writer for the Lymnaeidae in 1911 and some grati- 
f^'ing results were obtained. The family Planorbidae offers better charac- 
teristics for purposes of classification than does the Lymnaeidae, there 
being a greater diversity of structural features among the different genera. 

For the data in the present work a large number of species of the family 
Planorbidae, from different parts of the world, were dissected. These repre- 
sent a majority of the generic groups so far published, in addition to 
several new genera. As in the study of the land mollusks, the genitalia have 
been of the greatest assistance. Few new groups were necessary because 
those already published, of which there were many, were adequate to 
represent the different anatomical features involved. 

In the new classification here presented, great stress is laid on the 
differences in the male genitalia, the size of the preputium and vergic sac; 
the characteristics of the prostate diverticula and the prostate duct; the 
presence or absence of a stylet on the verge; flagella present or absent on 
the vergic sac; a penial gland in the preputium and whether this has an 
internal or an external duct or none at all; the opening of the sperm 
canal in the verge, whether at the end or on the side; the number of 
retractor muscles of the penial complex; and the nature of the ovotestis, 
whether the diverticula are in a double series or are multiple. 

Other anatomical features also aid in classification, as the shape of 
the kidney, whether it is smooth or has a ridge; the condition of the jaws, 
whether simple or fragmented; the form of the radula teeth; the shape of 
the stomach and the turns of the intestine from stomach to anus. The 
pseudobranch also offers some criteria although this organ is fairly uniform 
in the family. It does effectively separate the Planorbidae from the Bu- 
linidae, the pseudobranchs of the two groups being markedly different. 
For generic purposes, the shell offers less assistance than the organs of 
the animal, although the shell sometimes presents characteristics of generic 
importance. 

45 



46 The Molluscan Family Planorbidae 

It has been possible to recognize four subfamilies of the family Planor- 
bidae based on fundamental anatomical differences, and all of the genera, 
as far as they have been examined, readily fit into this subfamily classi- 
fication. A few groups, as Taphius, Biomphalaria, Platytaphius, and Tro- 
chorbis, are still unknown anatomically, but it is believed that when 
examined they will be found to fit into this classification. Many species 
of the family still remain of wliich the animal characteristics are unknown 
and it is possible that new genera or subgenera will need to be made for 
their inclusion. It is confidently believed that the classification herein 
presented will form a reliable foundation on which to build future knowl- 
edge which may be obtained concerning this interesting family. 

ANATOMICAL KEYS TO GROUPS* 

Key to Subfamilies 

la. Prostate a single row of diverticula usually placed on a separate prostate duct. . .2 

b. Prostate with multiple diverticula usually placed on the sperm duct 3 

2a. Vergic sac with flagella Segmentininae (see p. 47) . 

b. Vergic sac without flagella Planorbinae (see p. 46). 

3a. Prostate forming a fan-shaped pattern in cross section, penial gland duct on 
outside of preputium, ovotestis consisting of several diverticula arranged 

fanwise Helisomatinae (see p. 47). 

b. Prostate forming a finger-shaped pattern with few diverticula, penial gland duct 

inside preputium, ovotestis with paired diverticula. .. .Planorbulinae (see p. 48). 

Key to Genera of Planorl)inac+ 

la. Prostate diverticula on separate duct, simple, unbranched at end 2 

b. Prostate diverticula not on separate duct, branched at 

end Aiifitralorhift (see i). 90). 

2a. Verge with .stylet, outlet of sperm canal at side 3 

b. Verge without stylet, outlet of sperm canal at end 6 

3a. Shell with many closely coiled whorls not increasing greatly in diameter 4 

b. Shell with few loosely coiled whorls rapidly increasing in diameter 5 

4a. Left side of shell flat without central depression Anisus s.s. (see p. 57). 

b. Left side of shell with deejily excavated 

depression (Subgenus) Bathijomphnlus (see p. 62). 

5a. Left side of shell with rounded whorls on a plane surface. . .Gi/m»/i<.s s.s. (see p. 66). 
b. Left side of shell with whorls depressed as though reamed 

out (Subgenus) Torquis (see p. 72) . 

6a. Vergic sac le.ss than one-fourth length of preputium Planorhis (see p. 51). 

b. Vergic sac longer than preputium 7 

7a. Vergic sac about as long as preputium, shell 5 mm. or more in diameter, 

not costate 8 

b. "\>rgic sac much longer than preputium. shell 3 mm. or less in diameter, 

usually costate Anniger (see p. 75) . 

8a. Species inhabiting Africa Afroplanorbis (see p. 86) . 

b. Species inhabiting America Tropicorbis s.s. (see p. 85) 9 

*In using this type of alternative key the options are always arranged in couplets, the contrasting 
conditions being arranged as 'a' and 'b' under the same numeral. The reader always starts with la. 
If the description under la fits the specimen or concept under consideration, the numeral at the end 
of that line indicates the next couplet to be tried (except in those instances where la leads directly 
to an identification). If the .statement under la does not fit, the alternative under lb should, and so 
on through tile key until a group name is reached at the end of one of the options. This form of 
continuous and consecutive key is less confusing than the type in which descriptions to be compared 
are widely separated from each other and does not offer the technical diflScuIties of composition 
inherent in the indented or step form of key. — H.J.^'-C. 

tSome subgenera which have distinctive morphological characters are included in this key and in all 
succeeding keys to genera. 



A Xew Classification of the Family Planorbidae 47 

Oil. Shell with closely coiled whorls slowly increasing in diameter, orbicular 10 

b. Shell with loosely coiled whorls rapidly increasing in 

diameter (Subgenus) Latcorhis (see p. 85). 

10a. Ajierture without internal lamellae at any stage of 

growth Tropicurhi.s s.s. (see p. 85) . 

b. Aperture with internal lamellae during a i)art of the shells 

growth (Subgenus) Ohstrurtio (see p. 85). 

Key to Genera of Segnientininae* 

la. Genitalia with penial gland in preputium 2 

b. Genitalia without penial gland in preputium 5 

2a. An external penial gland duct on preputitmi 3 

b. Without penial gland duct on preputium 4 

3a. External duct very short, half as long as preputium; penial gland a simple 
cup attached 'to wall of preputium; flagella more than twice as long as 

vergic .sic, sausage-shaped, attached to short ducts Intha (see p. 112). 

b. External duct about four times as long as preinitium; penial gland sac-like, 
bifurcated; flagella consisting of small cylindrical sacs attached to very 

long ducts Pingiella (see p. 109). 

4a. PreiHitiinn narrow, club-shaped; vergic sac longer than preputium; verge 

slender with vergic appendage at end Segmentina (see p. 96). 

b. Preputium wide, pear-shaped; vergic sac shorter than preputium; verge wide 

at upper part, without penial appendage Hippeutis (see p. 100). 

5a. Flagellum long and narrow; vergic sac and preputium of about the same 

length ; shell more than 5 mm. in diameter 6 

b. Flagellum wide and short; vergic sac about twice as long as preputium; shell 

very small, 1.5 mm. in diameter Acrorbis (see p. 121). 

6a. Flagellum as long as penial complex, swollen or club-.?haped at 

sununit Polypylis (see p. 104) . 

b. Flagellum shorter than penial complex, not swollen at summit, often bifid 

at the end Drepanotrema (see p. 114) 7 

7a. Shell with rounded pcrijihery Drepanotrema s.s. (see p. 118). 

b. Shell with angulated or carinated i>erii)hery. . (Subgenus) Fo.<>!^ulorbis (see !>. 118). 

Key to Genera of Helisomatinae+ 

la. Prejiutium with i)enial gland but without penial duct ... .PlnnorbariJi^ (.see p. 166). 

b. Preputium with external penial gland duct 2 

2a. Penial complex with one retractor muscle 3 

b. Penial complex with two retractor muscles 6 

3a. Penial complex with but little constriction between vergic sac and preputium; 

Ijenial gland duct about half as long as preinitium. . .Hclisoma s.s. (see p. 124) . . .4 
b. Penial complex with notable constriction between vergic sac and preputium; 

penial gland duct as long as the jn-eputium. .. (Subgenus) Scminolina (seep. 129). 
4a. Penial complex with vergic sac and preputium equal in length, the preputium 
much wider than the vergic sac; jjenial gland duct several times as long as 

preputium, in a coil between vergic sac and preputium 5 

b. Penial complex with vergic sac shorter than the preputium. which is elongate; 

penial gland short and thick, not longer than preputiimi 6 

5a. Shell with simple aperture, not campanulate. .. (Subgenus) Picrostnna (see p. 134). 
b. Shell with campanulate or bell-shaped aperture (Subgenus) Planorbella (seep. 150). 
6a. Penial duct on outside of preputium very short, slender, placed between 
vergic sac and preputium; penial gland an elongated cup with wide 

a]ierture Carinifex (see p. 154). 

b. Penial duct twice as long as in 6a, thick, wide, extending from upper part of 
ju'eputium to vergic sac; penial gland pijie-shaped, with a long "stem" at- 
tached to a short "bowl" Parapholijx (see p. 161). 

*One subgenus is included among the groups differentiated in tliis key. 
tSeveral subgenera are also differentiated in this key. 



48 The Molluscan Family Planorhidae 

Key to Genera of Planorbulinae* 

la. Penial gland sausage-shaped with round, closed duct 2 

b. Penial gland flattened, ovate, with open, channel-like duct 3 

2a. Penial duct very short leading from gland direct to muscular collar or 

diaphragm Menet us s.s. (see p. 183) . 

b. Penial duct long, extending up the side of the preputium to the muscular 

collar or diaphragm (Subgenus) Micromenetus (see p. 187). 

3a. Penial gland connected with muscular collar by an open duct as long as the 
gland, lying above a single diagonal projection of the left pilaster; seminal 
vesicle composed of many diverticula forming a mulberry appearance on 

the surface Flanorbuln s.s. (.sec \\. 173). 

b. Penial gland connected with muscular collar by an open slit in the muscular 
wall of the preputium, the two pilasters sending branches from both sides 
to this slit; seminal vesicle consisting of many short diverticula stretched 
along a large part of the ovisperm duct Frotnenetus (see p. 178). 

SYSTEMATIC LIST OF GENERA AND SUBGENERA 
RECOGNIZED IN THIS WORK 

In the following list the genera and subgenera are arranged in the sequence 
which appears most in accord with their structural features. Several groups 
are unknown anatomically and these are marked by an asterisk. They are 
placed in the subfamilies and near the genera with which they appear to 
be affiliated. The fossil species, it is obvious, can never be known anatomi- 
cally and these are placed near those genera which they most nearly re- 
semble. The fossil groups are marked by a dagger. Two groups of uncertain 
affinities, one recent and one fossil, are placed at the end of the family 
sequence. The type species is indicated following the name of each genus 
or subgenus. 

Family PLANORBIDAE H. and A. Adams, 1855 
Subfamily Planorbinae Pilsln-y, 1934 

Genus Planorbis Geoffrov, 1767 Helix planorbis Linn. 

Genus Anisus Studer, 1820 (Gray, 1847) 

Subgenus Anisus SS Helix spirorbis Linn. 

Subgenus Costorbis Lindholm,t 1926 Planorbis strauchianus Clessin 

Subgenus Bathyomphalus (Ag.) Charp., 1837. .Helix contorta Linn. 

Genus Odontogyrorbis L6renthey,t 1906 Planorbis krambergeri Halavdts 

Genus Gyraulus (Ag.) Charp., 1837 

Subgenus Gyraulus SS Planorbis albiis Miiller 

Subgenus Torquis Dall, 1905 Planorbis parvus Say 

Genus Armiger Hartmann, 1840 Nautilus crista Linn. 

Genus Taphius H. and A. Adams, 1855 Planorbis andecolus Orb. 

Genus Tropicorbis Pilsbry and Brown, 1914 

Subgenus Tropicorbis" SS P. liebmanni T>nn\s.Qr = orbiculus 

Morelet 

Subgenus Obstructio Haas, 1939 Planorbis janeirensis Clessin 

Subgenus Lateorbis F. C. Baker (New) Planorbis pallidus C. B. Adams 

Genus Afroplanorbis Thiele, 1931 Planorbis sudanicus Martens 

Genus Syrioplanorbis F. C. Baker, f new name for 

Heterodfscus West., preoccupied Planorbis libanicus West. 

Genus Biomphalaria Preston, f 1910 Biomphalaria smithi Preston 

Genus Australorbis Pilsbry, 1934 Planorbis glabratus Say 

Genus Anisopsis Sandberger,t 1875 Planorbis calculus Sandberger 

*One subgenus is included in this key. 

tThe anatomy is not known for any member of this group. 

JA group represented by fossils only. 



A New Classification of the Family Planorbidae 49 

Siil)family SEGMENTININAE F. C. Baker (New) 

Genus Segmontina Fleming, 1817 Planorbis nitidus Mtiller 

Genus Hippeutis (Ag.) Charj)., 1837 Planorbis complanatus Drap. 

Genus Polypylis Pilsi)rv, 1906 Planorhis largillurli, Phil. 

Genus Helicorbis Benson, f 1855 Planorbis umbilicalis Benson 

Genus Trochorbis Benson,! 1855 Trochorbis trochoid iics Benson 

Genus Pingiella F. C. Baker (New) Pyramidula pi'ipinoi-^lx Ping and Yen 

Genus Intha Annandale, 1922 Intha capitis Annandale 

Genus Drepanotrema P^ischer and Crosse, 1880 

Subgenus Drepanotrema SS Planorbis anatinum Orb. 

{=yzabalensis C. and F.). 

Subgenus Fossulorbis Pilsl)rv, 1934 Planorbis cnltratus Orb. 

Genus l'arai)l:in()rl)is Ilanna,! 1922 Planorbis condoni Hanna 

Genus Platytaphius Pilsl)ry,t 1924 Planorbis hcteroplearus P. and V. 

Genus Acrorl^is Odhner, 1937 Acrorbis petricola Odhner 

Subfamily HELISOMATINAE F. C. Baker, 1928 

Genus Helisoma Swainson, 1840 

Subgenus Helisoma SS Planorbis anceps Menke 

{ = bicarinatus Sowb.) 

Subgenus Seminolina Pilsl^ry, 1934 Physa scalaris Jay 

Subgenus Pierosoma Dall, 1905 Planorbis trivolvis Say 

Subgenus Planorbella Haldeman, 1842 Planorbis campanulatus Say 

Genus Carinifcx W. G. Jiinney, 1863 Planorbis newberryi Lea 

Genus Vorticifex Meek, J 1870 Carinifex tryoni Meek 

Genus Perrinilla Hannibal, J 1912 Helisoma cordillerana Hannibal 

Geiuis Parapholyx Hanna, 1922 Pomplinhjx effiisa Lea 

Genus Pompholopsis Call,! 1888 Pontjiholap-sis irhitei Call 

Genus Planorbarius Froriep, 1806 Hdix contra Linn. 

Subfamily PLANORBULINAE Pilsbry, 1934 

Genus Planorbula Haldeman, 1840 

Subgenus Planorbula SS Planorbis armigerus Say 

Sul:)genus Haldemanina Dall, 1905 Planorbis icheatleyi Lea 

Genus Promenetus F. C. Baker, 1935 Planorbis exacuous Say 

Genus Menetus H. and A. Adams, 1855 

Subgenus Menetus SS Planorbis opercularis Gould 

Subgenus Mieromenetus F. C. Baker (New) . . . Planorbis dilatatus Gould 

Genus Planorbifex Pilsbry, J 1934 Planorbis vanvlecki Arnold 

Groups of Uncertain Affinities 

Genus Choanomphalus Gerstfeldt,t 1859 Choanomphalus maacki Gerstfeldt 

Genus Poecilospira Morch,! 1853 Valvata multiformis Zeiten. 

tThe anatomy is not known for any member of this group. 
♦ A group represented by fossils only. 



VII. 
SYSTEMATIC ACCOUNT OF THE SUB- 
FAMILIES, GENERA, AND SUBGENERA 
RECENT AND FOSSIL 

PLANORBIDAE, together with the Physidae and Bulinidae, are 
animals with spiral shells; the genitalia and the respiratory and 
excretory organs are on the left side. The shell of Planorbidae is 
typically sinistral in some groups (Helisoma) and pseudodextral or iiltra- 
dextral in many groups. The shell is carried almost vertically in the typi- 
cally sinistral groups but leans toward the left in other groups, principally 
the smaller forms. In these groups the spire is beneath and the umbilicus 
is above, these being respectively the right and left sides of the shell. The 
central tooth of the radula is always bicuspid. In Physa it is multicuspid. 

The chief feature separating the Planorbidae from the other members 
of the Limnophila is the presence of an accessory breathing organ, the 
pseudobranch, which takes over the office of a gill when the animal is sub- 
merged and can not obtain free air. The flattened, 'planorboid' shell is, of 
course, another distinctive feature of the family. 

The groui)s of genera related to Bulinm and Physopsis have in the past 
been included in the family Planorbidae because of the similarity of the 
radulae and the presence of a pseudobranch. But this organ in Bulinus is 
different from the pseudobranch in Planorbidae, being in the form of folds 
or ridges while in the Planorbidae it is smooth and leaf-like. There are also 
differences in the genitalia, principally in the penial complex. These differ- 
ences suggest that Bulinus, Physopsis, and other related groups should 
form a separate family Bulinidae. This has been recognized by Germain 
in his mollusks of France (1931) and by Larambergue in a recent publica- 
tion (1939). The Indian genus Indoplanorbis has been shown by the latter 
author to be related to Bulinus and its place appears to be with the 
Bulinidae. 

Subfamily PLANORBINAE H. A. Pilsbry, 1934 

The subfamily of H. and A. Adams is equivalent to the family Planorbidae 
as now recognized by systematists. In the Planorbinae the prostate diver- 
ticula are all simple sacs placed in a single row along the whole length of a 
long prostate duct which is separated from the sperm duct into which it 
enters. The ovotestis has the diverticula arranged in a double row. An 
apparent exception is found in tiie genus Australorbis where the single row 
of glands is placed directly on the sperm duct and the ends of the prostate 
diverticula are branched. The kidney is usually rounded and without a 
superposed ridge. Here again Australorbis is an exception, having a ridged 
kidney as in Helisoma. 

Tvpe genus Planorbis Geoff roy. 

There is considerable variation among the different genera grouped in 
Planorbinae, principally in the jaws, the radulae, and the presence of a 
penial stylet. These differences may be tabulated as follows: 

Radula with serrated marginals placed hijih up on the reflection: Planorbis, 
Bathyomphahis, Anisms, Gyraulus, Armiger. 

Radula with claw-like marginals on a long reflection: Australorbis, Tropicorbis. 

50 



Subfamilies, Genera, and Subgenera — Recent and Fossil 51 

Radiila with interstitial cusps on laterals or marginals: Australorbis, Twpicorbis. 

Jaw in three pieces, a superior and two lateral jaws: Tropicorbis, Auslralorbis, 
Ajroplanorbis. 

Jaw fragmented with many plates: Planorbis, Bathyomphalus, Anisus, Gyraulus, 
Armig( r. 

^'erge with stylet : Anisus, Bathyomphalus, Gyraulus. 

Verge without stylet: PUmorbis, Armiger, Tropicorbis, Ajroplanorbis, Auslralorbis. 

Several groups are unknown anatomically and hence their position in 
the system can not be definitely known until the animal has been examined. 
Such are Costorbis, Syrioplanorbi)^, Taphius, and Biomphalaria. The fossil 
group supposed to belong to this subfamily, Odontogyrorbis, can only be 
placed by shell resemblances and this points to the Planorbinae. 

■ Genus PLAXORBIS Cleoffroy, 1767 
Genotj'pe by tautonomy Helix planorbis Linn. 

1767. Planorbis Geoffroy, Traite Coq., Paris, p. 12. No tj'pe designation. 

1774. Planorbis Muller, (part) Verm. Terr. Hist., II, p. 152. No type designation. 

1833. Anisus Fitzi.n-ger. (part) Beitr. Lande.sk. Oester. Ill, ]k 111 (Xon Dejean. 1821, 
Coleoptera). 

1847. Spiralina H.\rtm.\nx, Herrmannsen, Ind. Gen. Mai.. 11, V- 286. As synonym of 
Planorbis. 

1850. Tropidiscus Steix, Schn. u. Muscheln Berlins, p. 76. As subgenus. Tj'pe desig- 
nated by Clessin, 1886 — Planorbis marginatus Drap. 

1852. Anisus [Fitzixger] Herrm.\xxsex, Ind. Gen. Mai., Suppl. p. 9. Tjqie: Pla- 
norbis umbilicatus Miiller. As fixed b,v Gray, 1847. Xot Anisus Studer, 1888. 

1855. GyrorbU Moq.-T\xd., (part) Hist. Xat. Moll. Terr, et Fluv. France, II, p. 428. No 
type cited. As genus. 

1855. Omalodiscus Bexsox, Jour. Asiatic Soc. Bengal, XXIV, p. 127. T3-pe designated 
by Kennard and Woodward, 1924, Omalodiscus marginatus Drap. 

1883. Tropidiscus Fischer, Man. Conch., p. 509. Xo type designation. As section. 

1885. Tropidiscus Westerluxd, Fauna Palaearc. Reg., V, p. 64. X"o type cited. As sub- 

genus of Planorbis. 

1886. Tropidiscus Clessix, Syst. Conch.-Cab.. XVII, p. 34. Type Planorbis marginatus 

Drap. As subgenus. 
1898. Planorbis (Geoffroy) vox M.artexs, Biol. Centr. Amer., :Mo11.. p. 380. Xo type 

cited. As genus. 
1902. Tropidiscus Westerluxd, Had. Jugoslav. Akad., 151, p. 120. Genotype Helix 

planorbis Linn. As subgenus. 
1905. Placorbis DR.\p.\RX.\rD, X'at. Hi.st. Moll. France, p. 138. (vide Lindholm, Archiv. 

fiir Mollu.sk., 58 year. Heft 6. p. 252). 

1905. Tropidiscus D.\ll, Alaska Moll., p. 85. Type Planorbis umbilicatus Muller = 

Planorbis complanatus Stein. 

1906. Otnalodiscus D.\ll. X'autilus XIX, p. 105. Comments on nomenclatorial position 

but cites no type. 
1917. Tropidiscus Sees. Ann. Musei X'at. Hungarici, XV, pp. 40, 141. Type Tropidiscus 

planorbis (Linn.). As genus. 
1921. Tropidiscus Germaix'. Rec. Ind. Mus., XXI, p. 7. Type Planorbis planorbis 

(Linn.). As subgenus. 
1923. Planorbis (of Muller 1774) Wexz, Fossil. Cat., Part, 22, p. 1523. Genotype 

Planorbis planorbis (Linn.). As genus. 

1926. Tropidiscus (of Stein) Lixdholm. Archiv. fur Mollusk., 58 year. Heft 6. p. 252. 

Ideogenotype Helix planorbis Linn. As genus. 

1927. Planorbis Kexx.ard and Woodw.xrd, Syn. British Xon-Marine !Moll., p. 66. Tj'pe 

by tautonomj' Helix planorbis Linn. As genus. 



52 The Molluscan Family Planorbidae 

1929. Planorbis (of Miiller 1774) Haas, Trab. Mus. Cien. Nat. Barcelona, XIII, p. 379. 

Tj'pe evidently intended to be Planorbis phniorbis (Linn.). As genus. 

1930. Planorbis H. B. Baker, Oc. Papers, Mus. Zool. Univ. Mich., No. 210, p. 42. Type 

b.y absolute tautonomy Helix planorbis Linn. As genus. 

1931. Planorbis Germain, Moll. Terr, et Fluv. France, II, pp. 516, 521. No type desig- 

nation. As genus and subgenus. 
1931. Tropidiscm Thiele, Handbuch, IV, Teil 2. p. 481. Type Plaiiorbis planorbis 
(Linn.). As subgenus. 

1935. Tropidiscus Soos, Allat. Kozlem., XXXII, p. 29. Planorbis carinatus Miiller and 

Planorbis planorbis (Linn.) cited. As subgenus under genus Anisus. 

1936. Planorbis (of Miiller 1774) R\as, Abh. Senckn. Natur. Gesell., No. 431, p. 25. 

Planorbis planorbis (Linn.) by absolute tautonomy. As genus. 

Shell (plate 77, figs. 26-28) discoidal with few whorls, regularly in- 
creasing in diameter; upper and lower (left and right) sides flattened; a 
carina encircles the body whorl on the left side; aperture small, rounded, 
or oval, the right side in advance of the left side. 

Animal. External appearance. The body is small, the foot short, 
rounded before and pointed behind; tentacles long and filiform; eyes 
sessile at the inner base of the tentacles; when removed from the shell the 
animal of Planorbis planorbis has a blackish or lead-colored mantle, a 
yellowish liver, and a pinkish ovotestis. 

ANATOMICAL CHARACTERISTICS 
PLATE 1 

GENITALIA. Male Organs (fig. 1). Seminal vesicle (SV) 3.5 mm. 
long and 0.7 mm. wide, elongate-cylindrical, covered for the most part by 
small pustule-like glands. Sperm duct (SPD) very long (14 mm.) adherent 
to the oviduct. The prostate (PRS) is about 5 mm. long and consists of 
forty to forty-five diverticula placed in a single row on a long prostate 
duct (PD) which is separated from the sperm duct. Both sperm duct and 
prostate duct enter the smaller vas deferens near the vagina (fig. 1, YD, 
PD). The prostate diverticula are cylindrical in form and a trifle more 
than 0.5 mm. in length. A cross section through the prostate and oviduct 
shows the relationship between the sperm duct and the prostate duct 
(fig. 7). The vas deferens is a long (12 mm.) narrow tube (VD). 

The penial complex is elongated (fig. 2), the preputium (PR) is long 
(3 mm.), cylindrical, and the vergic sac (VS) is short (0.7 mm.) and some- 
what less in diameter than the preputimn. There is one long and narrow 
retractor muscle (R^M) attached to the vergic sac near the junction of the 
latter with the preputium. A group of five or more small muscles near the 
base of the preputium and a longer, narrow muscle attached to the upper 
part of the preputium have been called supporting muscles (SM) . They are 
not attached to the columella muscle but to the fore part of the head. The 
long, narrow muscle may play a part in retracting the preputium after 
copulation. 

Internally (fig. 4) the preputium has two vertical pilasters and a large 
number of longitudinal muscular ridges (PL). The walls of the preputium 
are thin but the walls of the vergic sac are thickened, especially at the 
summit where the vas deferens enters. The verge (V) is short and wide in 
repose and nearly fills the vergic sac. A section through the verge and a 



Subfamilies, Genera, and Subgenera — Recent and Fossil 53 

part of the vas deferens shows the sperm canal to be located in the center 
and to have a central exit (fig. 5). The absence of a distinct muscular 
ring or diajihragm is noteworthy. 

Female Organs. The sperraatheca (S) in the specimens examined is 
about 1.5 mm. long and 1 mm. wide, globular or pear-shaped, and attached 
to the uterus by a short, narrow duct about 1 mm. long (SD). The vagina 
(VG) is very short (less than 0.5 mm.) and wide. The uterus (U) is as 
wide as the vagina and is about 5 mm. long. The nidamental gland (NG) 
is as long as the uterus and surrounds a large part of the oviduct (see 
fig. 1). It is greatly lobulated. The free oviduct (OD) is short (about 2 
mm.) and about as narrow as the sperm duct. Beneath the albumen gland 
the sperm duct and the oviduct are joined to form the ovisperm duct (fig. 
6). The albumen'gland is large (3.5 by 2 mm.) and is a mass of small sacs 
(AL). A small duct enters the carrefour (CF) which in turn enters the 
oviduct in front of the junction of that organ with the sperm duct. 

Hermaphrodite Organs. The ovotestis (OT) consists of many club- 
shaped diverticula placed in a double row (fig. 8). The ovotestis is buried 
in the cell-mass of the liver (fig. 9). The ovisperm duct (SO) is divided 
into two external parts separated by the seminal vesicle, through which it 
passes. One portion, about 5 mm. long, extends back of the sperm duct at 
its junction with the oviduct and gradually enlarges as it enters the 
seminal vesicle. A smaller tube, about 3 mm. in length, passes from 
the seminal vesicle to the ovotestis. 

The genitalia of Planorbis planorbis have been figured by several 
European conchologists. Germain's figure (1931, p. 523, fig. 533) is in 
general like the figures in this work, but there is lack of detail. The 
spermatheca is shown in a more elongated form, but this organ is subject to 
more or less variation. The large seminal vesicle is indicated by a swelling 
in the ovisperm duct. L. Soos's figure (1917, p. 41) agrees in general with 
that shown in this work. The prostate shows relatively the same number of 
diverticula. The spermatheca is shown on a long duct and the spermatheca 
is pear-shaped, not rounded as was observed in all specimens personally 
examined. Germain's figure is like Soos's in this respect. There appears to 
be some variation in this organ perhaps due to seasonal or sex condition. 

The penial complex in Soos's figure is not shown in sufficient detail, but 
the position of the retractor muscle indicates a short vergic sac. The 
seminal vesicle shows an enlargement. A. Soos's figure (1935, p. 25) appears 
more nearly correct, showing for the first time the separate prostate duct. 
The spermatheca, however, is shown of a pyriform shape and on a long 
duct. The figure of the related species carinatus JMiiller (p. 24) given by 
Soos is more like the Poland specimens of planorbis personally examined. 
The duct of the prostate is shown as very short while in the Poland ma- 
terial the free portion of this duct is much longer before entering the vas 
deferens. The lower portion of the female complex is shown very much 
longer in Soos's figure than was observed in the Poland specimens. 

Respiratory and Renal Systems. The pseudobranch (P, fig. 3) is leaf- 
shaped, flattened, about 2.5 mm. long and 2 mm. wide. The rectum (R) 
pierces it after bordering the columella muscle and the anus has its exit at 
the lower edge (A). The respiratory tube or pncumostome (PS) forms a 



54 The Molluscan Family Planorbidae 

short V-shaped lobe to the right of the pseudobranch. It is large and can 
be greatly expanded. 

The kidney (plate 46, fig. 9) is very long and narrow (10 mm. long, 
1 mm. wide), the glandular portion occupying only about one-eighth of the 
length. The ureter is short (1 mm. long), narrowly tubular and turns 
sharply to the left into the mantle cavity. A cross section of the kidney at 
about midway of its length shows the lumen to be flattened and widened 
with a vein at each end (fig. 10). There is no ridge on the lower side. The 
pericardium is long-oval in shape, 2.5 mm. long and 1.2 mm. wide. 

Digestive System. The stomach (plate 48, figs. 6, 7) is elongated and 
pyriform in sliape, the blind sac about as long as the stomach. The intes- 
tine runs directly forward and does not make a backward loop as in 
Helisoma and some other groups. The stomach does not show distinct 
divisions into crop and gizzard. The buccal sac is elongated and shortly 
pyriform in shape, the fore part near the mouth somewhat tubular. The 
radula sac is distinct and rounded. The salivary glands are much elongated, 
cylindrical, and joined behind. 

The jaw (plate 50, fig. 21) is horseshoe-shaped and is composed of 
many small plates, about thirty on the upper or horizontal part, the lower 
or cutting edges V-shaped. 

The radula (plate 67, fig. 7) formula is 24-1-24, 25-1-25, or 26-1-26 
and the number of rows of teeth varied as follows: 175, 176, 205, and 209. 
The central tooth is bicuspid with a wide base of attachment, tlie cusps 
long and spade-shaped; lateral teeth (1-10) tricuspid, the cusps large and 
spade-shaped, the mesocone largest and longest, the reflection reaching 
nearly to the lower edge of the base of attachment. Intermediate teeth 
(11-13) with the reflection reaching only about half way to the lower edge 
of the base of attachment, with four cusps, the ectocone split into two 
cusps. Marginal teeth (14-20) very narrow with the reflection placed high 
up on the tooth, with four cusps which become subequal toward the outer 
margin of the radula membrane. The outer marginals are very narrow, the 
width being about one-fourth of the heiglit and there are four short, sub- 
eciual cusps. In one membrane some of the marginal teeth (20) had the 
entocone split into two sharp cusps. This was rare and occurred only in 
atyjiical rows. 

The central teeth varied somewhat in width in the same membrane. For 
example, in rows 1 to 156 the upper part of the central tooth measured 6 
microns and the lower part of the base of attachment measured 12 microns 
in width. In rows 157 to 176 these measurements were 5 and 12 microns 
respectively. In most membranes the central teeth were very uniform in 
width. 

For the above anatomical data eight specimens were examined, col- 
lected by Mr. A. Jankowski from a pond in Swidry-Mate, 25 km. south- 
east of Warsaw, Poland. No parasitic worms (cercariae) were observed in 
any of the specimens examined. 

Geographical Distribution. The genus Planorbis, as herein understood, 
is distributed throughout Europe from Sweden southward to the Medi- 
terranean and from Great Britain eastward to western Russia. It is also 
found in northern Asia (Siberia), Asia Minor, and northern Africa. 

Species Considered as Valid. Although many species now assigned to 
other genera were originally placed in the genus Planorbis there are now 



SubjafNilies, Genera, and Subgenera— Recent and Fossil 55 

hut relatively few sjjecies which belong in this genus as now restrieted. 
The best recognized of these are: 

Planorbis planorbis (Linn.) Planarbis atticus Bgt. 

Pln7iorbis carinntus Mi'iller l^lmiorbis sieversi Mouss. 

Planorbis aniotddi Germain Planorbis antiochianus Locard 
Planorbis marmoratus Michaud 

Geological Distribution. Oligocene to Recent time, according to Wenz. 
It is probable that some of the sj^ecies included in this genus by paleon- 
tologists really belong to other grouj)s. 

Remarks. The genus Planorbis is peculiar anatomically in the form of 
the prostate with many single diverticula and in the comparatively small 
size of the vergic sac as compared with the preputium. The verge, also, is 
very small, short; and wide, differing markedly in this respect (as far as 
known) from any other group of planorbes in Europe. The nature of the 
genitalia and the form of the shell set this group apart as a distinct genus 
of the family Planorbidae. 

For many years, the author for this genus and the species for its type 
have been in dispute. Some authors (Tryon 1872, 1884, Fischer 1883, 
Baker 1902, Binney 1865, Dall 1870, Fischer and Crosse 1879) quote 
Ciuettard as authority (Mem. Acad. Sci., p. 151, 1756). Other authors have 
cited the genus as of ■Miiller (Verm. Hist., p. 152, 1774) with Helix cornens 
Linn, as type (Dall 1905, Pilsbry and Bequaert 1927, Baker 1931). A few- 
have used Guettard 1756 and ^liiller 1774 in combination with Helix 
corneus as genotype (Germain 1921, 1931). Another group of authors have 
cited Geoffroy (Traite Coq., Paris, p. 12. 1767) with Helix planorbis Linn, 
as genoty])e (Kennard and Woodward, 1924, 1926). 

Guettard 1756 is pre-Linnean and also non-binomial and would appear 
to be ruled out on these accounts. Geoffroy 1767 is post-Linnean but this 
author was not in all cases binomial and is rejected by some students for 
this reason. Kennard and Woodward (1924, p. 9), however, have presented 
very convincing arguments in favor of retaining the Planorbis of this 
atithor. The Planorbis of ]\Killer (1774) is preferred by some late writers 
(Dall 1905, Pilsbry and Bequaert 19271, who cite the Helix corneus of 
Linnaeus as genotype, giving ^Vlontfort 1810 (Conch. Syst., II, p. 270) as 
the first author to select a genotype. 

However, whether Geoffroy or Miiller is selected, the genotype for both 
is Helix planorbis Linn., the selection of which is governed by the rules of 
tautonomy (see H. B. Baker, 1930). After reviewing the evidence very 
carefully there seems to be no valid reason why Planorbis Geoffroy, 1767, 
should not be used, as advocated by Kennard and Woodward (1924). The 
Helix corneus Linn, is the genotype of Planorbariiis Froriep, 1806. The 
name Tropidiscus Stein (1850) is in use bv several European authors 
(Germain 1921, L. Soos 1917, A. Soos 1935,'Thiele 1931) but this name 
is a synonym of Planorbis, having the same genotype. Helix planorbis Linn. 

Genus ANISUS Studer, 1820 (Gray, 1847) 
Type Helix spirorbis Linn, selected b}' Gra}- in 1847 

1820. Anisus Studer, Natursvis. Anzeiger Allg. Schweiz. Ges. Gesammt. Xaturwiss., 

3te Jahrg., Xr. 12, p. 91. 
1840. Spirorbis Sw.mxson, Treat. Malac, p. 337. Tyjic Planorbis vulgaris Swain. Not 

Spirorbis Daudin, 1800 (Vermes). 



56 The Molluscan Family Planorhidae 

1840. Spiralina Hartmaxn, Erd-und Siissw.-Ga.sterop., 'Syst. Uebersicht.' Xude name. 
1843. Planorbina Haldeman, Mon. Freshwater Univalve Moll., Physidae, p. 14. Type 

designated by Pilsbrv 1934, Planorbis spirorbis Linn. Not Plmiorbina Dall, 

1905. 
1847. Anisus Studer, Gray, Proc. Zool. Soc, p. 180. Tj-pe Helix spirorbis Linn. 
1847. Spirorbis Herrmannsen, Ind. Gen. Mai., II, p. 492. Type Planorbis spirorbis 

(Linn.). 
1850. Tropidiscus Stein (part). Lebend. Schneck. und Musch. Berlins, p. 76. 
1855. Gijrorbis Moquix-Tandon, Moll. Ter. Fluv. France, II, pp. 423, 428. Type desig- 
nated bv Lindholm, 1926, Planorbis rotundatus Foiv.=^ Planorbis leucostoma 

Millet. "Not Gyrorbis Fitz., 1833. As genus. 
1870. Anisus Fitz. Dall, An. Lye. Nat. Hist., N.Y., IX, p. 352. Type Anisus vortex 

(Linn.). As section of Planorbis. 
1883. Gyrorbis Fischer, Man. de Conch., p. 507. Type Planorbis rotundatus Poir. As 

section of Planorbis. 

1885. Gyrorbis Westerlund, Fauna Palaearc. Reg., Y, p. 64. No type cited. As sub- 

genus of Pla7iorbis. 

1886. Gyrorbis Clessin, Sj'st. Conch. Cab., XVII, p. 34. Type Planorbis rotundatus 

Poir. As subgenus. 

1897. Diplodiscus Westerlund, Act. Soc. Fauna Flora Fennica, XIII, p. 115. First 
species Planorbis vortex (Linn.). Not Diplodiscus Dies., 1836, Trematodes. 

1899. Spiralina Hartmann, von M.^rtens, Biol. Cent. Amer., Moll., p. 395. Type desig- 
nated Planorbis vortex (Linn.), by Lindholm in 1922 and Kennard and Wood- 
ward in 1924. 

1902. Diplodiscus Westerlund, Rad. Jugoslav. Akad., 151, p. 120. First species. Helix 
vortex Linn. As subgenus of Planorbis. 

1905. Paraspira Dall, Alaska Moll., pp. 82, 86. T^-pe by original designation Planorbis 
rotundatus Poir. '= Planorbis leucostoma Millet. As section of Planorbis. 

1909. Tr;;.s'^;Vf Honigmann, Zeitsch. f. Naturw., 81, p. 296. Type designated by Lind- 
holm, 1926, Playiorbis rotundatus Poir. As synonym of subgenus Anisus. 

1917. Gyrorbis L. Soos, Ann. Musei Nat. Hungarici, XV, jip. 49, 143. Gyrorbis spirorbis 
first species (Anatomy). As genus. 

1921. Diplodiscus Westerlund, Germain, Rec. Ind. Mus., XXI, \). 7. Type Planorbis 
vortex (Linn.). Non Dies. 1836. As subgenus. 

1921. Paraspira Germain, op. cit., p. 7. Type Planorbis rotundatus Poir. As subgenus. 

1922. Spiralina (Hartmann) von Martens, Lindholm, Ann. Musee Zool. L'Acad. Sci., 

Russia, Tome XXIII, p. 320. Type designated by Lindholm Planorbis vortex 
(Linn.). As subgenus. 

1923. Gyrostoma Haas, Archiv. f. Molluskund., LV, pp. 43, 45. Type designated 

Gyrostoma rotundatum Poir. = Planorbis leucostoma Millet. Not Gyrostoma 

Kirby and Spence 1828, Knietniewski 1897, or Hesse 1909. 
1923. Spiralina von Martens 1899, Wenz, Fossil. Cat., pars. 22, p. 1529. Genotype 

Spiralina vortex (Linn.). As genus. 
1923. Paraspira Wenz, op. cit., p. 1530. Genotype Paraspira rotundata Poiret. As 

genus and subgenus. 
1926. Spiralina (Hartmann MS) von Martens, Kennard and Woodward, Syn. Brit. 

non-marine Moll., p. 68. Type Helix vortex Linn. As subgenus. 
1926. Spiralina (Hartmann MS) von Martens, 1899, Lindholm, Archiv. f. Mollusk. 

58 year. Heft 6, p. 252. Ideogenotype Helix vortex Linn. As genus. 
1926. Anisus (Studer, 1820) Lindholm, op. cit., p. 253. Ideogenotype Planorbis 

spirorbis (Linn.). As genus. 
1926. Anisiis (S. Str.) Lindholm, op. cit., p. 253. Monogenotype Spirorbis vul- 
garise^ Planorbis vortex var. of Drap.). As subgenus. 
1929. Anisxis (Studer, 1820) H\as, Trab. Mus. Cien. Nat. Barcelona, XIII, p. 281. Type 

evidently Planorbis spirorbis (Linn.). As genus. 
1929. Spiralina (von Martens, 1899) Haas, op. cit., p. 381. Type evidently Helix 

vortex Linn. As genus. 



Subfa/inlies, Genera, and Subgenera — Recent and Fossil 57 

1931. Spifdliiia (Hartiuann, von Martens), Gekmaix, Moll. Ter. Fluv. France, II, 
1>. 526. Type probably intended to be Planorhis vorlex (Linn.). As subgenus. 

1931. Anisus (Studer, 1820) Thh^lk, Handbuch, iv teil, p. 480. As genus. 

1931. Anisus (SS) Thiele, op. cit., p. 481. IVpe Planorhis Icucostoma Millet. As sub- 
genus of A)iisus. 

1931. Spiralinn (Hartmann) Thiele, o\i. cit., p. 481. Type Planorhis vorlex (Linn.). 
As subgenus of Anisus. 

1934. Anisus Studer, 1820, Pilsbry, Proc. Acad. Nat. Sci., LXXXVI, p. 62. Type 

Helix planorhis Linn, designated by Gray in 1847. As genus. 

1935. Spiralina (Hartmann) von Martens, 1899, Soos, AUat. Kozleni., XXXII, p. 29. 

As subgenus of genus A^iisus. 
1935. Animis Studer, 1820, Soos, op. cit., p. 29. As genus. 

Subgenus ANISUS SS. 

Ty]:)e Helix spirorhis Linn. 

Shell (plate 77, figs. 20-22, Anisus spirorhis (Linn.), figs. 16-18, A7iisus 
leucostomus (Millet), fig. 19, Anisus vortex (Linn.) ) discoidal with many 
tightly coiled whorls very slowly increasing in diameter, all of the whorls 
visible on both sides of the shell; whorls rounded or with a sharp carina 
at the periphery; aperture small, rounded or ovate, modified in carinate 
species by the peripheral carina. 

Animal. Externally resembling that of Planorhis. 

ANATOMICAL CHARACTERISTICS 
PLATES 6-7 

GENITALIA. Male Organs (plate 6, fig. 12, spirorhis; plate 7, fig. 2, 
leucostomus; plate 7, fig. 6, septemgijratus) . Seminal vesicle (SV) long, 
cylindrical, convoluted, about three times the diameter of the ovisperm 
duct. Sperm duct (SPD) very long and slender (5 mm. in spirorhis, 7 mm. 
in septemgyratus, 3 mm. in leucostomus, and 4 mm. in vortex). The 
prostate is long in vortex and septemgyratus and short in spirorhis and 
leucostomus. The number of diverticula vary correspondingly, in vortex 
being about sixty, in septemgyratus fifty-seven, in spirorhis about twenty, 
and in leucostomus over twenty. The diverticula are sac-like, cylindrical, 
and are placed on a duct separated from the sperm duct which joins the 
latter some distance above the vagina to form the vas deferens. Cross 
sections through the oviduct and prostate show the separation of the two 
ducts (plate 6, fig. 3 vortex, fig. 8 spirorhis). The prostate duct varies in 
length in the different species. It is about 1 mm. long in spirorhis, but only 
about 0.2 mm. long in vortex, septemgyratus, and leucostomus. The diver- 
ticula of the prostate vary in length and diameter as shown in the figures 
(plate 6, fig. 12; plate 7, figs. 2, 6). The vas deferens is shorter than the 
sperm duct by about half its length, and, as usual, is a narrow tube. 

The penial complex is greatly elongated in all species of the genus 
Anisus. It is about 3.5 mm. long in vortex, 2 mm. long in spirorhis and 
leucostoinus. The preputium is always shorter than the vergic sac, which 
may be nearly twice as long in vortex as in spirorhis (figs. 1 and 13 on 
plate 6). The preputium is cylindrical, usually swollen at the upper part. 
The vergic sac is elongated, pyriform or club-shaped, narrowing greatly in 
diameter where it joins the preputium. There is one long, narrow retractor 
nniscle and apparently no supporting muscles. 



58 The Molluscan Family Plauorhidae 

Internally the penial complex has certain distinctive features, as shown 
in fig. 10 on plate 6 ispirorbis) . The preputium has two vertical ridges or 
pilasters. Between the preputium and the vergic sac there is a thick 
muscular ring which shows as a swelling on the exterior surface of the 
upper part of the preputium. A large papilla (PP) is suspended between 
the walls of the muscular ring, the walls of which are very thick. 

Below the large muscular swelling there is a second smaller ring which 
is here called the diaphragm (D). It is relatively thin and is capable of 
considerable contraction and expansion, which causes the hole or foramen 
in the middle, as viewed from above, to be small or large. Buchner shows 
this ring (Ringwulst) in his fig. 1 on plate 5, but it is there shown in 
section as almost closed and is placed below the thick papilla. In those 
specimens of the four species examined the ring has been widely open and 
the papilla has been extended below the area of the ring (plate 6, fig. 4, 
vortex, fig. 10, spirorbis) . The papilla is larger and somewhat differently 
shaped in the figures on plate 6, varying in this respect from Buchner's 
figure. Possibly changes due to breeding condition may be the reason for 
this difference. 

The verge is long, cylindrically pyriform in shape above and tapering 
rapidly below the middle of its length to form a slender tube, at the end 
of which is a small, horny stylet. The sperm canal turns to the side just 
above the stylet where it has its exit on the side of the verge (plate 6, figs. 
4, 5). The stylet is sharp and needle-like, bulbous at the upper part where 
it is attached to the verge. There is a fine groove extending along one 
face of the stylet (plate 6, figs. 2, 5; plate 7, fig. 5). The verge of vortex 
is much narrower than that of any other species examined. With the excep- 
tion of the 'Ringwulst' the penial complex of the four species of the genus 
Anisus agrees with the description and figure of Buchner. 

Female Organs. The spermatheca is much elongated and cylindrical 
in vortex, spirorbis, and septemgijrntus with a spermathecal duct about as 
long as the spermatheca (plate 6, fig. 12). In leucostomus, however, the 
spermatheca is short and bulbous with a short, thick spermathecal duct 
(plate 7, fig. 2). In several specimens of septemgyratus the spermatheca 
was cylindrical and acutely pointed at the summit. One specimen contained 
a large spermatophore (plate 7, fig. 6). The spermatheca and its duct are 
over 1 mm. long in spirorbis, but less than a millimeter in leucostomus. 

The vagina (V) is very short (less than 0.3 mm.) in all species. The 
uterus (U) is long and cylindrical in vortex, septemgyratus, and spirorbis, 
but rather short and wide in leucostomus. The nidamental gland is long 
and cylindrical in vortex, spirorbis, and septemgyratus but large and swol- 
len in leucostomus. The oviduct shows the same differences, being long and 
cylindrical in vortex, spirorbis (3 mm. long), and septemgyratus, but is 
short (about 2 mm. long) and of larger diameter in leucostomus. The ovi- 
duct is always of greater diameter than the sperm duct (see figs. 2 and 
6, plate 7, fig. 12, plate 6). The albumen gland is elongated, narrow, and 
somewhat arched (plate 6, fig. 9; plate 7, figs. 2, 6, AL). 

Hermaphrodite Organs. The ovotestis is made up of many club-shaped 
diverticula arranged in a double row on the ovisperm duct (i)late 6, fig. 
12; plate 7, fig. 2, OT, spirorbis and leucostomus). Two diverticula of 
leucostomus are shown on plate 6, fig. 7. Several diverticula of vortex had 
ripe ova. The ovisperm duct is divided into two parts separated by the 



SubjaniiUes, Genera, and Subgenera — Recent and Fossil 59 

yeiuinal vesicle, as in the ii'enus Planorbis. The portion between the seminal 
vesicle and the ovotcstis is enlarged in septemgyratus and Icucostomus 
(plate 7, figs. 2, 6) but is of small diameter in spirorbis and vortex. In the 
first two species the enlargement is of the same diameter as the seminal 
vesicle, of which it may be a part. The portion of the ovisperm duct be- 
tween the seminal vesicle and the oviduct is a long, slender, smooth tube 
in leucostoinus, but in vortex, septemgyratus, and spirorbis there are small 
pustule-like bulgings which ai)i)ear to be glandular extensions of the sem- 
inal vesicle. 

The genitalia of the four species here recorded are in the main similar 
to Buclmer's fig. 11, tafcl 4, which is copied by Simroth. Germain's figure 
of rotundatus (=leucostonius) is similar but lacks detail (1931, pp. 527, 
539). The prostate is shown too long as compared with the Poland speci- 
mens personally examined. Soos's figure (1917, p. 50) is like those in this 
work, as is also the figure of vortex (p. 53). 

Respiratory and Renal Systems. The pseudobranch is large, narrow, 
and flattened in all species examined. It is pierced by the rectum which is 
long and narrow. The pneumostome is cylindrical and in the specimens 
examined is rolled into a cylindrical tube with a large cleft extending its 
whole length. It varies in length in the different species (plate 6, fig. 6 
vortex, fig. 11 spirorbis, and plate 7, fig. 1 leucostonius) . 

The kidney (plate 47) is very long and narrow, the glandular portion 
occupying only a small part of the entire length. In spirorbis (fig. 13) it 
is 5 nun. long and about 0.3 mm. wide but in vortex it is 12 mm. long and 
over 0.3 mm. wide. The ureter is very short and is sharply bent upward 
into the mantle cavity. The pericardium is very short as compared with 
total length of the kidney. Cross sections show no evidence of a ridge. In 
vortex (fig. 14) the kidney is as thick as wide and the veins are placed at 
the base of the rounded lumen. In leucostomus (fig. 15) the kidney is wider 
than high with the veins lower on the lumen. In these species the kidney is 
somewhat triangular in shape to fit the sharp angle caused by the pe- 
ripheral carina of the shell. In a cross section of spirorbis (fig. 16) the 
kidney is seen to be very wide and much flattened with the veins near the 
middle of the lumen. The kidney of Anisus does not differ in any essential 
way from that of Phinorbis. 

Digestive System. The stomach, buccal sac, and general digestive sys- 
tem are similar to these organs in Planorbis. The jaw (plate 50, fig. 25) 
is similar to that of Planorbis with about twenty plates on the upper part. 
The side jaws are also fragmented. 

The radula (plate 67, fig. 6, spirorbis) formula is 15-1-15 or 16-1-16. 
The numbers of rows of teeth vary from 185 to 195. Central tooth with two 
spade-shaped cusps reaching nearly to the lower edge of the base of attach- 
ment. Lateral teeth (1-10) tricus]')id, about as wide as high at first but 
becoming narrower toward the marginal teeth. There is but one inter- 
mediate tooth (11), four-cuspid, with the reflection short and wide. 
INIarginal teeth (12-15) narrow, four-cuspid, the reflections very short and 
wide. The fourth cusp appears as a splitting of the ectocone. The formulae 
for the other species examined are as follows: 

sejptemgyratus 16-1-16 with 130 rows 
vorlex 16-1-16 with 142 rows 
leucostomus 16-1-16 with 130 rows 



60 The Molluscan Family Plauorbidae 

The teeth are all very uniform in form. Anisus has fewer teeth in a row 
than Planorbis, the formula of which is 25-1-25, but the teeth are similar 
in form and number of cusps. 

For the anatomical information herein presented the following ma- 
terial has been available, all received from Mr. A. Jankowski, of Warsaw, 
Poland: 
vortex, Eight examples from stream in meadow at Jab-Tonna, 18 km. northeast of 

Warsaw, Poland. 
spirorbis, Eight specimens from a trench in Struga, 12 km. northeast of Warsaw, 

Poland. 
septemgyratus, Three examples from turfy meadow in Drewnica, 4 km. northeast 

of Warsaw, Poland. 
leucostomus, Three sj^ecimens from small ponds in Bielany Park, Warsaw, Poland. 

Geographical Distribution. The genus Anisus is distributed throughout 
Europe from Great Britain to Russia and Siberia and southward to Italy 
and Algeria. Thus the distribution is about the same as that of Planorbis. 
One species is reported from China {paravortex). This distribution may 
be enlarged when other si)ecies arc examined anatomically. 

Species Considered as Valid, The following species are understood to 
conform to the concept of Anisus. 

Ariisus spirorbis (Linn.) Anisus johanseni (Mozley) 

Anisus vortex (Linn.) Anisus perezi (Dupuy) 

Anisus septemgyratus (Ziegler) Anisus jragilis (Millet) 

Anisus leucostoynus (Millet) Anisus paravortex (Ping and Yen) 

Anisus vorticulus (Troschel) Anisus millcti (Germain) 

Anisus villai (Adami) Anisus charteus (Held.) 

Anisus ressmannianus (West.) Anisus centrogyratus (West.) 
Anisus compressus (Michaud) 

Geological Distribution. This genus begins about the middle of the 
Miocene period. 

Remarks. The group of European planorbids under the name Anisus 
differs from the genus Planorbis notably in the form of the penial complex 
(compare fig. 4, plate 1, Planorbis, with fig. 10, plate 6, Anisus). In Pla- 
norbis the vergic sac is only one-fourth as long as the preputium while in 
Anisus this organ is always longer than the preputium and the verge is 
long and narrow and bears a stylet at the end, which is absent in Planorbis. 
The presence of the muscular ring and papilla in Anisus is also another 
striking difference. The seminal vesicle also differs markedly in the two 
genera. The shell is always flattened and many-whorled but from the shell 
alone the two groups could scarcely be separated generically. 

The proper name for the group of European planorbids typified by 
Planorbis spirorbis, vortex, and leucostomus has been in considerable doubt. 
The name most commonly found in the literature, used by Germain, 
Lindholm, Soos, Kennard and Woodward, and others, is Spiralina, a nude 
name published by Hartmann in 1840. In 1899, von Martens used the 
name for the European Planorbis vortex and the American Planorbis 
cultratus and sumichrasti. The last two species are now members of the 
genus Drepanotrema. Thus the type of Spiralina becomes Planorbis vortex 
and this species was formally designated the type by Lindholm in 1922 
(p. 320), and by Kennard and Woodward in 1924 (p. 68). But in 1847 
Herrmannsen (Ind. Gen. Mai. II, p. 286) listed Spiralina Hartmann in the 
synonymy of typical Planorbis without comment or question, thus, as 



Subfamilies, Genera, and Subgenera — Recent and Fossil 61 

H. B. Baker remarks (1930, p. 49) 'effectually clothing and simultaneously 
killing the name Spiralina.' Thus no subsequent use of this name is per- 
missible. Dall (1905) used the name Diplodisciis Westerlund and cited 
Planorbis vortex as type, this being the first species listed. But this name is 
preoccupied by Diesing in Trematodes. 

In 1934 (Proc. Phil. Acad. Sci., j). 62), Pilsbry revived the early name 
Anisus Studer, 1820 and gave some very good reasons for accepting this 
name for the group tyjufied by Planorbis vortex and spirorbis, accepting 
Gray's subsec^uent designation of Helix spirorbis Linn, as type. In this 
connection he remarks 

Gray's type designation of 'H. spirorbis' is valid for Anisus only if the identity of 
spirorbis Studer and spirorbis Linn, is admitted. I see no sufficient reason for doubt- 
ing it. A more serious question relating to Anisus is whether a generic name is valid 
when admitted by its author to be for a group formed by the union of two prior 
genera, and containing nothing else. Unfortunately Opinion 9 of the International 
Commission on Nomenclature is not explicit on this point, but as Anisus has been 
widely used it had better be retained. 

Other names have been proposed for this European group and would 
be available but for previous use in other groups. Spirorbis Swainson, 
Gyrorbis, Diplodiscus, Wuestia, and Gyrostoma are thus affected, as noted 
in the list of synonyms of Anisus. 

The writer agrees with Pilsbry that, since the name Anisus has had 
wide use in the literature it had better be retained for this group, since 
it was proi:)erly clothed as a genus by Gray in 1847. Anisus is used by 
Thiele in his Handbuch, 1931. The best interest of nomenclature is served 
by the use of Anisus rather than by coining a new name. 

Subgenus COSTORBIS Lindholm, 1926 
Type by original designation Planorbis strauchianus Clessin 

1926. Costorbis Lindholm, Archiv. fiir Mollusk., 58 year. Heft 6, pp. 253, 257. Mono- 
genot.vpe Planorbis strauchianus Clessin. As subgenus of Anisus. 

193L Costorbis Thiele. Handbuch. V, Teil 2, p. 48L Type A. (C.) strauchianus 
Clessin. As subgenus of Anisus. 

Shell (plate 76, fig. 3). Differing from Anisus in being heavily trans- 
versely costate, the body whorl angulated above and below, the aperture 
ciuadrate. 

Animal. The group is anatomically unknown but the shape of the shell 
would indicate that it should be grouped with Anisus. 

Geographical Distribution. Russia. 

Species Considered as Valid. The only species definitely referable to 
this subgenus is A7nsus (Costorbis) strauchianus (Clessin). 

Remarks. It is a question whether this group should be separated from 
Ani.ms. The shell of strauchiami.s is similar in form to that of Anisus 
septongyratus, differing principally in the costate sculpture. Clessin's fig- 
ure (copied from Conch. Cab., XVII, plate 31, fig. 5) is reproduced on 
plate 76, fig. 3. The original description of the shell appears on page 204 
of Clessin's work. 



62 The Molluscan Family Planorbidae 

Subgenus BATHYOMPHALUS (Agassiz MS) Charpentier, 1837 
Type Helix contorta Linn, designated by Herrmannsen in 1852 

1837. Bnthyomphalus Agassiz (MS) Ch.arpentier, Neue Denkschr. AUg. Schweiz. 

Gesell., I, no. 2, p. 20. 
1847. Polygyrus Gr.\y, Proc. Zool. Soc, p. 181. T^-pe Planorbis contortus (Linn.) (not 

of Say, 1818, or Beck, 1837). 
1850. Discoidina Stein, Leben. Schneck. und Musch. Berlins, p. 82. Type Planorbis 

contortus (Linn.). 

1852. Bathi/omphahis Herrm.annsen, Ind. Gen. Mai., II, Suppl., p. 16. Type Planorbis 
coJitortus (Linn.). 

1855. Bathyomphalus Moquin-T.\ndon, Hist. Nat. Moll. France, II, p. 443. As sub- 
genus. 

1870. Bathyomphalus D.\ll, Ann. X.Y. Lye. Nat. Hist.. IX, p. 352. Type Planorbis 
contortus (Linn.). As subgenus. 

1883. Bathyomphalus Fischer, Man. Conch., p. 507. Tyi)e Helix contorta Linn. As 
section of Planorbis. 

1885. Bathyomphalus Westerluxd. Fauna Palaearc. Reg.. V, p. 65. No tyjie cited. 

1886. Bathyomphalus Clessix, Conch. Cab., XVII, p. 34. Type Planorbis contortus 

(Linn.). As subgenus. 
1902. Bathyomphalus Westerluxd, Rad. Jugoslav. Akad., 151, p. 120. Type Helix 

contortus Linn. As genus of Planorbis. 
1905. Bathyomphalus Dall, Alaska Moll., pp. 83, 86. Type Planorbus contortus 

(Linn.). As section of Planorbis. 
1917. Bathyomphalus Soos, Ann. Musei Nat. Hungarici, XV, pp. 45, 142. Type 

Bathyomphalus contortus (Linn.). As subgenus. 
1921. Bathyomphalus Germ.mn, Rec. Ind. Mus., XXI, p. 7. Type Planorbis contortus 

(Linn.). As subgenus of Planorbis. 
1923. Bathyomphalus Wenz, Fossil. Cat., Pars 22, p. 1633. Genotype Bathyomphalus 

contortus (Linn.). As genus. 
1926. Bathyomphalus Lixdholm, Archiv. fiir Mollusk.. 58 year. Heft 6, p. 253. Mon- 

ogenotype Planorbis contortus (Linn.). As genus. 
1926. Bathyomphalus Kexx.ard and Woodward. Syn. British Non-marine Moll., p. 68. 

Type Helix contorta Linn. As subgenus of Planorbis. 
1929. Bathyomphalus H.aas, Trab. Museo Cien. Nat. Barcelona, XII, j.. 383. Type 

evidently Planorbis contortus (Linn.). As genus. 
1931. Bathyomphalus Germ.^in, Moll. Terr. Fluv. France, II, p. 520. Type evidently 

Planorbis contortus (Linn.). As subgenus of Planorbis. 
1931. Bathyomphalus Thiele, Handbuch, IV, Teil 2, p. 481. Type Anisus (B.) con- 
tortus (Linn.). As subgenus of Anisus. 
1935. Bathyomphalus Soos, Allat. Kozlem., XXXII, p. 30. Planorbis contortus (Linn.) 

cited. As genus. 

Shell (plate 77, figs. 23-25). Small, ultradextral with the whorls more 
nimierous and more closely coiled than in Anisus, increasing very slowly 
in diameter, equally visible above and below, but the spire whorls (left 
side) forming a wide depression, a false umbilicus, not present in Anisus. 

Animal. Not difi^ering in general characteristics from Anisus. 

ANATOMICAL CHARACTERISTICS 
PLATE 3 

GENITALIA. Male Organs (fig. 10) . Seminal vesicle (SV) very long 
(3.5 mm.), of larger diameter than the ovisperm duct with many small 
tuberculous glands protruding from the surface. Prostate long (about 
3 mm.) and composed of forty-eight to fifty relatively short and wide 



Subfamilies, Genera, and Subgenera — Recent and Fossil 63 

diverticula (fig. 10, PRS, fig. 8). The i)rostate duct is a narrow tube about 
1.5 nnn. long from the prostate to its junction with the sperm duct to form 
the vas deferens (fig. 10, PD, SPD). In the natural position the prostate 
lies over the sperm duct and until separated from this organ the prostate 
diverticula appear to be directly attached to the sperm duct (see fig. 8, 
PD). This junction is placed higher uj) on the uterus than in Planorbis or 
Anisus. The vas deferens is a long (4.5 mm.) narrow tube which enters the 
vergic sac without enlargement. 

The penial complex (fig. 9) is very long and narrow, the prcputium 
(PR) being a little more than half the length of the vergic sac (preputium 
1.3 mm. vergic sac 2 mm.) . The narrow and cylindrical vergic sac is greatly 
contracted for about a third of its length near its connection with the 
preputium. There' is one long and narrow retractor muscle attached to the 
summit of the preputium. Internally, the anatomy of the penial complex 
is the same as in A?nsiis. 

Female Organs, The spermatheca is cylindrical, 1 mm. long, attached 
to the vagina by a narrow spermathecal duct a little more than 1 mm. long. 
The vagina (V) is very short (0.3 mm.) and wide. The uterus (U) is long 
(2 mm. long, 0.2 mm. wide) and narrowly cylindrical. The nidamental 
gland (XG) is long (about 3 mm.) and of larger diameter than the uterus 
(about 0.3 mm.). The oviduct (OD) is long (about 4 mm.) and narrowly 
cylindrical. The albumen gland is about the shape of that organ in Anisus 
(see plate 7, fig. 2). 

Hermaphrodite Organs. The ovotestis is like that organ in Planorbis 
and Anisus. The diverticula are long and cylindrical and packed closely on 
the ovisperm duct (plate 3, OT, fig. 7). The ovisperm duct lies at each end 
of the seminal vesicle, of about the same length in each division, (about 2 
mm.) and is a small, smooth tube (SO). 

The figure in Germain (1931, pp. 521, 532) does not agree with the 
Poland specimens in all respects. The penial complex (p) shows the vergic 
sac as much swollen, while in the specimens examined it was long and 
narrowly cylindrical. The relative lengths of the female and male systems 
is shown much shorter than was observed in the Poland specimens. Details 
of the prostate and ovotestis are not shown. The spermatheca in both 
figures is the same. 

Soos's figure (1917, p. 47) is similar to the ones here presented and is 
somewhat clearer than those of Germain. The prostate shows the great 
number of short diverticula, the spermatheca is on a long duct, and the 
penial complex is like the Poland specimens here figured. 

Respiratory and Renal Systems. The pseudobranch (jilate 3, fig. 5. P) 
is about as in Anisu>i, but is smaller and narrower. The pneumostome (PS) 
is larger than in Anisus but is otherwise similar. 

The kidney (plate 46, fig. 19) is long and narrow (7 nnn. long, 0.5 mm. 
wide) with a sharply reflected ureter. A cross section of the kidney (fig. 
20) shows a laterally jiyriform lumen with the veins at about the center of 
the section at each end. There is no ridge on the ventral side of the kidney 
but there is a rounded bulging on the left side that does not appear on 
the right side. 

Digestive System. The stomach (plate 48, fig. 8) is greatly elongated, 
pear-shaped, with a large blind sac, two-thirds as long as the stomach. 



64 The MoUuscan Family Planorhidae 

The intestine crosses over the oesophagus and extends toward the forward 
part of the body, but there is no bending backward with a posterior loop 
as in the Helisoniatinae. As in Anisus, there is no sharp division into crop, 
gizzard, and pyloris. The pyloric portion of the stomach appears to merge 
with the intestine. Germain states that it is absent. The buccal sac is as 
in Anisus. 

The jaw is like that of Planorbis planorbis, the superior portion having 
about twentv plates. 

The radula (plate 68, fig. 1) formula is 15-1-15 with 140-145 rows of 
teeth. Central tooth bicuspid, nearly reaches to the lower margin of the 
base of attachment. Lateral teeth (1-8) are tricuspid with a small addi- 
tional cusp above the ectocone, placed high up on the reflection. The inter- 
mediate teeth (9-11) differ by having the reflection placed higher on the 
tooth, with four cusps, the ectocone split into three cusps. Marginals (12- 
15) with five cusps are like the intermediate teeth, the reflection very high 
on the tooth. The outer marginal (15) is very narrow. 

For the anatomical data herein presented, four specimens were dis- 
sected, collected by A. Jankowski, at Drewnica, a turfy ground 4 km. 
northeast of Warsaw, Poland. 

Geographical Distribution. This group extends throughout Europe 
from the British Isles and Portugal eastward to Russia and Siberia, as 
far east as Kamchatka (Eyerdam, 1928). Southward the distribution in- 
cludes the countries bordering the Mediterranean Sea and the Caspian Sea. 

Species Considered as Valid. Ajiparently but two species are included 
in this group: Anisus ( Bathyoniphalus) contortus (Linn.) of Europe and 
Asia, and Anisus (Bathyoniphalus) dispar (Westr.) of Sweden and Russia. 

Geological Distribution. From the Miocene period to the Recent 
period. 

Remarks. In anatomical features Bathyoniphalus so nearly resembles 
Anisus that there seems little reason for recognizing the group as distinct. 
The genitalia strongly resemble those of Anisus septemgyratus. The in- 
ternal structure of the penial complex is similar. The kidney shows some 
differences in cross section (compare plate 46, fig. 20, with plate 47, figs. 
14-16). However, the shell is distinctive and the name has been in use 
for so long a period that it should be retained as a subgenus of the old 
group Spiralina { = Anisus). It should be noted that the radula formula is 
the same as in Anisus and different from that of Planorbis. 

Genus ODONTOGYRORBIS Lorenthey, 1906 
Type by original designation Planorbis krambergeri Halavats 

1906. Odontogyrorbis Lorexthey, Beitrage zur Fauna unci stiatigraphischen Lage der 

pannonischen Schichten in der Umgebung des Balaton-Sees. Resultate d. 

wissenschaftl. Erforschung des Balatonsees, I, 1, Art. 3, p. 121. Genotype 

Planorbis krambergeri Halavats. 
1923. Odontogyrorbis Wenz, Fossil. Cat., Pars. 22, p. 1538. Genotype Paraspira 

(Odontogyrorbis) krambergeri Halavats. As subgenus of Paraspira. 

Shell (plate 76, figs. 1, 2). Very small, discoidal, flattened, whorls rela- 
tively few, closely coiled, increasing very slowly in diameter, each side 
showing all of the volutions, right side slightly concave, left side almost 
flat; the aperture contains three lamellae, one on the base of the lip and 



Subfaf/iilies, Genera, and Subgenera — Recent and Fossil 65 

two on the iipjxT part of the aperture. The whole edge of the aperture is 
thickened. 

Geological Distribution. Lower PHocene. Fonyod, Kenese, and Nagy- 
vazsong. Hungary. 

Remarks. This group is noteworthy for the presence in the aperture of 
three folds or plicae, whence the generic name Odontogyrorbis. In general 
form the shell is related to Anisus vortex (Linn.), but is very much smaller. 
Halavats original specimens (plate 76, fig. 1) were broken and did not 
have the folds in the aperture. Lorenthey obtained specimens with the lip 
entire (plate 76, fig. 2). Wenz (1923, p. 1538) made Odontogyrorbis a 
subgenus of Paraspira {= Anisus). While the shell does resemble the type 
of Paraspira [Planorbis leucosfonms ^Millet) no member of the genus 
Anisus has as yet been recorded from the recent fauna with a dentate 
aperture. For the present Odontogyrorbis should be treated as an extinct 
genus related to Anisus. 

Species Considered as Valid. Odontogyrorbis krauibcrgeri (Halavats) 
is the only si:)ecies here ascribed to the genus Odontogyrorbis. 

It is of interest to note that the Pliocene planorbid fauna of the Lake 
Balaton region consist of sixteen species, all but one of which are extinct, 
the Pleistocene fauna contains fifteen species and races all of which belong 
to the recent fauna. Some of the supposed extinct species are closely related 
to their recent allies and might be considered geologic variations of the 
recent forms, in fact, ancestral species. 

Genus GYRAULUS (Agassiz :MS) Charpentier. 1837 

Type Planorbifi albii.s Miiller {^Planorbis hispidus Drap.) 
Designated by Dall in 1870. The first species originally included. 

1827. Planaria (part) Brown, Illust. Conch. Britain, ed. 1, exphm. plate LI, figs. 48, 49. 

Xon Miiller 1886 and Golze 1782 (Vermes). 
1837. Gyraulus (Agassiz MS) Charpentier. Xeue Denkschr. Allij. Schweiz. Gesell. 

I, no. 2, p. 21. 

1840. Gyraidus H.artmaxn, Syst. Uebers. Euroji. Gattun. (Tableau). 

1841. Trochlea Haldeman, Amer. Jour. Sci., XLII, p. 216. Xew name for Planaria. 

Brown. 
1844. Gyraulus Hartmaxx, FAxi unil Siissw. Gaster. der Schweiz. V. p. 89. 
1850. Nnutilina Stein, Leb. Schneck. und Muschl. Berlins, p. 80. Tyjie fixed by 

Clessin (1886) Planorbis albus Miiller. As synonym of Gyraulu.^. 
1855. Gyraulus Moquin-Tandon, Hist. X"at. Moll. France, II, p. 438. X'o type cited. 

As genus. 
1855. Giraulus Moquin-Tandon, op. cit., p. 423. Tyjiographical error for Gyraulus. 
1857. Gyraulus Gray, Turtons Manual. 2nd Ed., p. 234. In sj'iionj-my. 
1857. Gyrulus Gr.\y, op. cit., p. 234. Error for Gyraulus. 

1865. Gyraidus W. G. Binney, L. & F-W Sh. X. A., II, p. 128. Xo type cited. As .sub- 
genus of Planorbis. 
1870. Gyraulu.'i D.\ll, Ann. X. Y. Lye. X"^at. Hist., IX, p. 351. Type Planorbis albus 

Miiller. As subgenus of Planorbis. 
1883. Gyraulus Fischer, Man. Conch., p. 507. Type Planorbis albus Miiller. As section 

of Planorbis. 
1883. Caillaudia Bourciuign.at, Ann. Soc. Xat. Zool., (6), XV, p. 99. Monotype Cail- 

laudia angulata Bo\\rg. = Planorbis costulatus Krauss. (vide Pilsbrj' and 

Bequaert, 1927, p. 124). 




66 The Molluscan Family Planorhidae 

1884. Gyraulus Tryon, S. & S. Conch., Ill, p. 106. Example Planorbis deflectus Say. 

As subgenus or Planorbis. 

1885. Gyraulus Westerlund, Fauna Palaearc. Reg., V, p. 75. Type Pkuiorbis albus 

Miill. As subgenus of Planorbis. 

1886. Gyraulus Clessin, Conch. Cab., XVU, p. 33. Type Planorbis albus Miiller. As 

subgenus of Planorbis. 
1899. Gyraulus Martens, Biol. Cent. Amer. Moll., p. 392. Type Planorbis albus 

Miiller. As subgenus of Planorbis. 
1902. Gyraulus F. C. Baker, Moll. Chi. Area, II, p. 297. No type cited. As subgenus 

of Planorbis. 
1902. Gyraulus Westerluxd, Rad. Jugoslav. Akad., 151, p. 121. Type Planorbis albus 

Miiller. As subgenus of Planorbis. 
1905. Gyraulus Dall, Alaska Moll., pp. 83, 86. Type Planorbis albus Miiller. As 

subgenus of Planorbis. 
1912. Gyraulus Hannibal, Proc. Mai. Soc. London, X, p. 154. Type Planorbis albus 

Miiller. As subgenus of Planorbis. 
1915. Gyraulus Preston, Fauna Brit. India, Moll., p. 118. Type Planorbis albus 

Miiller. As section of Planorbis. 

1917. Gyraulus Soos, Ann. Musei Nat. Hungarici, XV, pp. 54, 144. T.vpe Planorbis 

albus Miiller. As genus. 

1918. Gyraulus Walker, Miscel. Pub., Mus. Zool., Univ. Mich., No. 6, pp. 12, 94. 

Type Planorbis albus Miiller. As subgenus of PUniorbis. 

1919. Gyraulus Annand.\le and Prashad, Rec. Ind. Mus., XVHI, p. 52. Type Planorbis 

albus Miiller. As genus (genitalia and radula). 

1921. Gyraulus Germain, Rec. Ind. Mus., XXI, pp. 8, 98. Tyi)e Planorbis albus Miiller. 

As subgenus of Planorbis. 

1922. Gyraulus Annandale, Rec. Ind. Mus., XXIV, p. 361. Tyiie Planorbis albus 

Miiller. As genus. 

1923. Gyraulus Wenz, Fos.sil. Cat., Pars 22, p. 1540. Genotype Gyraulus hispicbis 

Drap. = G. albus Miiller. As genus. 
1926. Gyraulus Kennard and Woodward, Syn. British Non-Marine Moll., p. 67. Type 
Planorbis albus Miiller. As subgenus of Planorbis. 

1926. Gyraulus F. C. Baker, Trans. Wis. Acad. Sci. Arts, XXII, p. 204. Type 

Planorbis albus Miiller. As genus. 

1927. Gyraulus Pilsbry and Bequaert, Bull. Amer. Mus. Nat. Hist., LIII, p. 124. 

Type Planorbis albus Miiller. As subgenus of Planorbis. 

1928. Gyraulus F. C. Baker, F. W. Moll. Wis., I, p. 364. Type Planorbis albus 

Miiller. As genus. 

1929. Gyraulus H.\as, Trab. Museo Cien. Nat. Barcelona, XIII, p. 384. Type 

evidently Planorbis albus Miiller. As genus. 
1931. Caillaudia Thiele, Handbuch, IV, 2nd Teil, p. 481. Type wrongly given as 

Anisus (C.) letourneuxi Bourg. (see Pilsbry and Bequaert, 1927, p. 124). 

As section under subgenus Armiger which is a subgenus of Ayiisus. 
1931. Gyraulus Thiele, Handbuch, IV, 2nd Teil, p. 481. Type Planorbis albus 

Miiller. As section under genus Anisus. 
1931. Gyraulus Germain, Moll. Terr, et Fluv. France, II, p. 533. No type cited. 

As subgenus of Planorbis. 
1935. Gyraulus Soos, Allat. Kozlem., XXXII, p. 30. No type cited. As genus. 

Subgenus GYRAULUS SS. 

Type Planorbis albus Miill. 

Shell (plate 77, figs. 1-3). Small, ultradextral, of comparatively few flat- 
tened \vhorls, equally visible above and below, usually rapidly enlarging in 
diameter; body whorl at aperture usually somewhat deflected, the aperture 
oblique; the periphery is usually median and in some species carinate; the 



Suhjamilies, Genera, and Subgenera — Recent and Fossil 67 

shell in several species is covered with short, hair-like projections of the 
periostracum (hirsute). 

Animal. External appearance (plate 70, fig. 5). The head bears the 
long, filiform tentacles characteristic of the Planorbinae with the eyes at 
the inner base. In general form the animal does not differ greatly from the 
figures of Tropicorbis on plate 78. No pigmentation, however, shows 
through the shell. 

ANATOMICAL CHARACTERISTICS 
PLATE 14 {Gyraulus albu.^) 

GENITALIA. Male Organs (fig. 7) . Seminal vesicle (SV) less than 1 
mm. long, composed of a few large diverticula or glands three or four times 
the diameter of the ovisperm duct. Sperm duct about 2 mm. long, of small 
chameter. Prostate (PRS) relatively long (1.5 mm.) consisting of about 22 
long (less than 0.5 mm.) diverticula attached to a separate prostate duct 
which is more than twice the diameter of the sperm duct. The free portion 
of the prostate duct is very short (0.2 mm.) and is of the same diameter 
as the sperm duct which it joins to form the rather short (1.2 mm.) vas 
deferens. A cross section through the prostate near the anterior end shows 
the sperm duct behind the prostate (fig. 9, SPD). 

The penial complex (fig. 2) is cylindrically elongated, a trifle more than 
1 mm. long, the vergic sac (VS) somewhat shorter than the preputium 
(PR). There is one long retractor muscle (R^I). The vas deferens is not 
enlarged as it enters the vergic sac. Internally (fig. 1) the preputium has 
thick walls, two pilasters, a muscular ring or diaphragm (D), and a de- 
pendent papilla (PP). The vergic sac has thin walls which increase in 
thickness toward the preputium. The verge (V) is elongate-pyriform, 
narrowed at the lower end where there is a stylet (ST). The stylet (fig. 8, 
ST) is dark brown, dagger-like with a ridge extending down the center. 
The opening of the sperm canal (SC) turns to one side above the stylet 
and has its exit on the side of the verge. 

Female Organs. The spermatheca (fig. 7, S) is elongate-pyriform, 
about 0.5 mm. long. It is joined to the vagina by a short, narrow duct about 
half as long as the spermatheca (SD). The vagina (VG) is very short and 
wide. The uterus (U) is wider than the vagina and the nidamental gland 
is wide and made up of many large diverticula (fig. 6, NG I . The uterus and 
gland are hidden in the figure by the large prostate. The free oviduct (fig. 
6, OD) is a short and narrow tube, looped beneath the prostate. Figure 6 
shows the relationship of the nidamental gland diverticula, the oviduct, 
the prostate, the sperm duct, which forms a loop, and the method of junc- 
tion to form the ovisperm duct. The narrow duct of the albumen gland 
and its connection with the oviduct is shown. The albumen gland is 
squarish or oval in shape and is composed of large gland cells. It contains 
cavities for the loop of the intestine, over which it lies (fig. 5). 

Hermaphrodite Organs. The ovotestis (OT) consists of a double row 
of pyriform diverticula attached to a large ovisperm duct (fig. 10). At the 
posterior end of the ovotestis the diverticula are crowded together (fig. 11). 
Several diverticula had developing egg cells. The ovisperm duct (SO) is 
divided into two parts, one at each end of the seminal vesicle (fig. 7, SO). 

The figures on plate 14 agree with that of Germain (1931, p. 533, fig. 
545). His figure, however, is not very clear. Soos's figure (1917, p. 55) is 



68 The MoUuscan Family Planorhidae 

similar in general form. The prostate shows fewer diverticula, however, and 
the spermatheca is on a longer duct than in the specimens from Poland 
examined, and they are figured more irregularly than was observed in the 
specimens j^ersonally examined. A. Soos's figure of Gyraulus laevis I Aid.) 
(1935, p. 27) shows a smaller number of prostate diverticula than appears 
normal for the genus. The spermatheca is also on a longer duct than in 
those species of the genus personally examined. No separate prostate duct 
is indicated. 

American species examined differ but little from the European Gyraulus 
albus. Gyraulus hirsutus (Gould), the nearest relative to albus, has from 
twenty to twenty-two diverticula on the prostate as in albus (plate 15, 
fig. 2). The seminal vesicle is practically the same. The penial complex 
has a much shorter preputium with a vergic sac one and one-half times 
as long as the preputium. This difference in form of the penial complex 
easily separates albus from hirsutus (compare fig. 2, plate 14, with fig. 2, 
plate 15). In Gyraulus deflectus obliquus (DeKay) there are forty divertic- 
ula on the prostate which is much longer than either albus or hirsutus. The 
prostate diverticula are also longer and club-shaped toward the end 
(plate 16, figs. 11, 12). Plate 16 fully illustrates the genitalia of obliquus. 
Gyraulus latestomus F. C. Baker (plate 19, fig. 9) has thirty-two diver- 
ticula on the prostate and the penial complex resembles that of obliquus. 
Gyraulus conve.vius cuius (Hutton) (plate 19, fig. 2) of India has about 
twenty-five prostate diverticula. The penial comjilex is very long and 
narrow but generally resembles that of hirsutus. The figures on plate 19 
agree with tliose by Annandale and Prashad (Rec. Ind. Mus., XVHI, 
p. 40) except that the spermatheca in the specimens examined is on a 
much longer duct than is shown in their figure. 

Respiratory and Renal Systems. The pseudobranch of Gyraulus albus 
(plate 14, figs. 3, 4) is broad, somewhat triangular, and flattened. The 
pneumostome is broad (fig. 3, PS). Figure 4 shows the pseudobranch cut 
open to indicate the vascular network of blood vessels. The rectum passes 
through the pseudobranch, as in other genera of Planorbinae. In Gyraulus 
hirsutus (plate 15, fig. 3) the pseudobranch is as broad as in albus. In 
Gyraulus deflectus obliquus the pseudobranch was observed to be of several 
forms (plate 16, figs. 13, 14, 15). It is in each case a broad, flattened 
organ. Figure 15 is an unusual form, possibly pathologic. In Gyraulus 
latestomus (plate 19, fig. 8) it is broad and flattened. In Gyraulus convexi- 
uscidus, from India (plate 19, fig. 3) it is flat and very thin and the pneu- 
mostome is very large. The pseudobranch appears to be similar in form in 
species from Europe, America, and India. 

The kidney (plate 48) is long and narrow in obliquus (fig. 4, 9 mm. 
long) and conve.xiusculus (fig. 17, 8.5 mm. long). In hirsutus (fig. 18, 2.5 
mm. long) and albus (which has the same form as hirsutus) the kidney is 
short and wide, quite unlike the kidney of the two species previously men- 
tioned. It is similar to that of vermicularis (fig. 3). Sections through the 
kidneys at about the middle show this organ to be flattened, the lumen 
much wider than high, and the veins to be placed at each end at about the 
center. Conve.vius cuius (fig. 8), hirsutus (fig. 19), and latestomus (fig. 11) 
are similar in form, but obliquus (fig. 10) is higher in proportion to width 
showing that the kidney is thicker than in the other species. There is no 
ridge. The ureter is short in convexiusculus and obliquus but longer and 
more tube-like in hirsutus and albus. 



SuhjamUies, Genera, and Subgenera — Recent and Fossil 69 

Digestive System. The stoiiiacli (plate 48, fig. 13j is cylindrical with 
the crop, gizzard, and jndoris plainly indicated. The intestine, after leaving 
the in'loris, makes a looj) over the oesophagus which extends backward, 
around the liver, and then loops forward to the rectum which has its exit 
on the pseudobranch. All species of typical Gyraulus examined have the 
same type of stomach and intestine. The buccal sac (of Gyraulus albun 
plate 70, fig. 13) is pyriform with the radula sac greatly developed and 
protruding behind (RL). The salivary glands (SG) are elongated, cylin- 
drical, and almost as long as the buccal sac. The ducts of these glands 
are long. 

The jaw (plate 50) is horseshoe-shaped and fragmented as in Planorbis 
and Anisus. Gyraulus hirsutus (fig. 17) has large plates, about forty on 
the entire jaw. Gyraulus albus has the same number. In Gyraulus dejiectus 
obliquus (fig. 18) the jaw is arched and consists of over fifty plates which 
are narrower than those of albus and hirsutv^. In latestomus the jaw is 
similar to that of obliquus and has over forty plates. 

The radula formula of Gyraulus albus (plate 68, fig. 9) is 18-1-18 with 
103 to 114 rows of teeth. The center tooth is bicuspid, the cusps long and 
narrow and reaching only about half waj- to the lower margin of the base 
of attachment. The laterals (1-9) are tricuspid with long, narrow cusps. 
The cusps of intermediate teeth ( 10-11 ) are short, placed high up on the re- 
flection, and the ectocone is split into two sharp cusps. The marginal teeth 
(12-18) have the reflection high up on the tooth, are wide and low and 
6-cuspid. The entocone is split into two small cusps, the mesocone is larger, 
and the ectocone cusps, three in number, are very small and sharp. In sev- 
eral membranes examined a very small 4th cusp appears on the 6th tooth 
and continues to the intermediate teeth. The center tooth varies in size in 
the 43rd to 62nd rows being a trifle wider at the top than in the first forty- 
two rows. The 86th to 103rd rows have a central tooth a little more than 
half the width of those in the 43rd to 62nd rows. 

The radula of Gyraulus hirsutus (plate 69, fig. 1) is similar to that of 
albus. The formula is 19-1-19, with 1-9 lateral teeth, 10-11 intermediate 
teeth, and 12-19 marginal teeth. There are 130 rows of teeth. The radula of 
Gyraulus dejiectus obliquus (plate 69, fig. 2) has a formula of 22-1-22, 
with 1-9 lateral teeth, 10-13 intermediate teeth, and 14-22 marginal teeth. 
There are 175 to 183 rows. Gyraulus latestomus has the formula 20-1-20, 
with 1-10 marginal teeth, 11-14 intermediate teeth, and 15-20 marginal 
teeth. There are 155 rows of teeth. 

Gyraulus convexiusculus has the formula 20-1-20, with 1-9 lateral 
teeth, 10-13 intermediate teeth, and 14-20 marginal teeth. The specimens 
examined differ from the figure by Annandale and Prashad (Rec. Ind. 
AIus., XVni, p. 55, fig. 8, B) where the inner laterals are shown as bi- 
cuspid, an unusual condition in the genus. Probably the entocones were 
not observed, for they were present in all of the laterals of the teeth per- 
sonally examined. The figure of the radula of Gyraulus euphraticu^ (C) 
by Annandale and Prashad is more correct in the tricuspid character of 
the lateral teeth. The radulae of all of the typical Gyraidus examined have 
been similar in character. 

For the above anatomical data the following material has been 
available: 
G. olbu.s, 25 specimens from park in Krolikarnia, a suburb of "Warsaw, Poland. 

Collected bv Mr. A. Jankowski. 



70 



The Molluscan Family Planorbidae 



G. hirsutus, 9 specimens from mouth of Bass Creek, Lake Xipissing, Ontario. Col- 
lected by Mr. A. LaRocque. 

G. deflect us obliquus, 13 specimens from Lake Chetek, Wisconsin. Collected by 
F. C. Baker; 6 specimens from Taylors Lake, near Quebec, Canada. Col- 
lected by Mr. A. LaRocque. 

G. latutomus, 3 specimens from Cedar Lake, Algonquin Park, Ontario. Collected 
by Mr. A. LaRocque. 

G. convexiusculus, 3 specimens from Calcutta. India, collected bj' Dr. B. Prashad. 

Geographical Distribution. The genus Gyraulus is practically world- 
wide in distribution, differing in this respect from all other genera of 
Planorbidae. Specific regions include North America, parts of the West 
Indies and northern South America, Europe, Asia, Africa, Australia, 
Malaysia, Fiji, New Caledonia, Philippines, and other islands of the 
Pacific Ocean. 

Below is given a list of some of the species of Planorbids believed to 
belong in the genus Gyraulus* Some of these species may be found, on 
anatomical examination, to belong to other subgenera or genera. The list 
is probably not complete. 

Species of Europe and Western Asia 



alhus Mliller 
acronicua Ferussac 
ancylus West. 
arcticus M oiler 
albopersicus Germain 
borealis Loven 
hourguignati Moitessier 
brondeli Raym. 
capocestianus V. Brus. 
crossei Bgt. 
devians Porro 
drapanauldi Jeff. 
gredleri Bietz 



he bra if us Bgt. 
infraliratus West. 
intermixtuii Mouss. 
janinensis Mouss. 
laevis Alder 
Umnophilus West. 
numidicus Bgt. 
piscinarum Bgt. 
polaris West. 
regulosus Lindholm 
socius West. 
tctragyrus West. 



Species of Australia and Tasmania 

essingtoneiisis Smith meridional^ Brazier 

gilberti Dunker planissimus Mousson 



Species of Africa 

abyssinicus Jickeli 

adansonii J. E. Gray 

aethiopicus Bourg. 

agraulus Boiu'g. 

andcrsoni Ancey 

avakubiensis Pils. and Beq. 

chedeaui Germain 

cockbruni Godwin-Au.sten 

costulatus Krauss 

crmvfordi Melville and Ponsonby 

fouladougouensis Germain 

gardei Germain 



gibbonsi Nelson 
kigeziensis Preston 
kisumieiisis Preston 
lamyi Germain 
leucochilus Melville 

and Ponsonby 
niisellus Morelet 
natcderuiia Krauss 
sperabilis Preston 
schweinfurthi Clessin 
tilhoi Germain 
toukotoensis Germain 



*In this faunal list, which Mr. Baker had never fully edited, the author's name follows 
each specific name with disregard for use of parentheses to indicate change from 
original generic assignment. — H.J.V-C. 



Subjani'dies, Genera, and Suhgeuera — Recent and Fossil 71 



Species of Fiji Group 

singularis Mousson 
Species of New Caledonia 



montrouzieri Gassies 

Species of 

associatus Westerlmui 
ocutua Clessin 
barrakporensis Clessin 
cnntori Benson 
cherraeiisis Godwin- Austen 
compressus Hut ton 
convexiusculus Hutton 
demissus Westerlund 
elegantulus Dohrn 
euphraticibs Mousson 
himlayaensis Hutton 
hohcnachcri Clessin 
haltoni Benson 
hiiptiocyclos Benson 
injraUneatus Martens 
intcrmixtus Mousson 
issykulensis Clessin 



i-us-siteri Crosse 



India and Asia 



labiatus Benson 

laidocensis Nevill 

liratus Westerlund 

nialacaensis Germain 

pangongensis Nevill 

proclivis Martens 

rotuln Benson 

saigonensis Crosse and Fischer 

saltensis Germain 

sivalensis Hutton 

stelzneri Dohrn 

stewarti Germain 

sumatranus Martens 

tondanensis Quoy and Gaimard 

velijer Annandale 

yeni Ping and Yen 



Species of Japan 



amplificaius Mori 
biwaensis Preston 
hiemantium Westerlund 
infirmus Mori 
iwaotakii Mori 

Species of the Philippines 

?)titidanensis Bartsch quadrasi Mollendorff 



japonicus Martens 
noziriensis Mori 
pulcher Mori 
tokyoensis Mori 



Species of America 

arcticioi (Beck in Moller) 
boetzked (Miller) 
burealis Lo\'en 
cyclostomus F. C. Baker 
dcflectus (Say) 



deflectus obliquus (De Kay) 
hirsutus (Gould) 
hornensis F. C. Baker 
Intistoiinis F. C. Baker 



Geological Distribution. According to Wenz the genus Gyraulus dates 
geologically from the Middle Eocene period. 

Remarks. The genus Gyraulus is closely related to Anisus in its ana- 
tomical features, especially the genitalia. In fact, Gyraidus, A7iisus, and 
Bathyomphalus form a natural group, based on their anatomy, particularly 
in the presence of a horny stylet on the verge. The shells of Anisus and 
Gyraulus, however, are quite unlike and the genera should undoubtedly 
be separated on conchological grounds alone. 

]\Iore than ninety species of Gyraulus are listed on the previous pages 
(excluding those from America). Some of these may be found to belong in 
other genera, when examined anatomically. Also, it is probable that several 
additional species should be added to those listed. Completeness is not 
claimed. All of those listed have been included in the genus Gyraulus by 
competent conchologists. 



72 The Molluscau Family Planorhidae 

Subgenus TORQUIS Dall, 1905 
Type by original designation Planorbis parvus Say 

1899. Gyrcudus (part) Martens, Biol. Cent. Amer., Moll., p. 392. Includes Planorbis 

parvus Say. 
1905. Torquis Dall, Alaska Moll., pp. 83. 86. Type Planorbis parvus Say. As section 

of subgenus Gyraulus. 
1918. Torquis W.\lker, Miscel. Contr., Mus. Zool., Univ. Mich., No. 6, pp. 34, 94. 

Type Planorbis parvus Say. As section of subgenus Gyraulus. 
1921. Torquis Germain, Rec. Ind. Mus., XXI, pp. 8, 150. Type Planorbis parvus 

Say. As subgenus of Planorbis. 
1923. Torquis Wenz, Fossil. Cat., Pars 22, p. 1627. Genotype Gyraulus (Torquis) 

Say. As subgenus of Gyraulus. 
1926. Torquis Kennard and Woodw.\rd, British Xon-Marine Moll., p. 67. As section 

of Gyraulus in synonymy. 
1926. Torquis F. C. Baker, Trans. Wis. Acad. Sci. and Arts. XXII, p. 204. Type Pla- 
norbis parvus Say. As subgenus of Gyrajilus. 
1928. Torquis F. C. Baker, Fresh-water Moll. Wis., I, p. 373. Type Planorbis parvus 

Say. As subgenus of Gyraulus. 

Shell (plate 77, figs. 4-6). Ultradextral, smaller than Gyraulus, SS, with 
the whorls less distinctly spirally striated, not hirsute, the base (left side) 
more or less concave, or excavated (appearing as though reamed out), the 
lip often slightly thickened within. 

Animal. Not differing from Gyraulus in general form. 

ANATOMICAL CHARACTERISTICS 
PLATE 17 (Gyraulus parvus) 

GENITALIA. Male Organs (fig. 6) . Seminal vesicle (SV) short (0.5 
mm.) of the same diameter as the sperm duct. There are a number of small 
glands which stand out like pustules. Sperm duct a trifle more than 1 mm. 
in length. Prostate (PRS» more than half as long as the sperm duct with 
eleven long and cylindrical diverticula. The free portion of the prostate 
duct is very short (PD), joining with the sperm duct to form the vas 
deferens. A cross section through the prostate shows the cylindrical or 
pear-shaped diverticula on a separate duct which has a greater diameter 
than the sperm duct (fig. 10). The vas deferens is at first a large duct 
but becomes smaller in diameter toward the penial complex (VD). It is 
about 1 mm. in length. 

The penial complex (fig. 6, VS, PR) is very long (about 1.3 mm.) and 
narrow, and cylindrical. The vcrgic sac is longer than the preputium. There 
is one large retractor muscle attached near the junction of the vergic sac 
with the preputium (fig. 12, RIM). The vas deferens is not enlarged as it 
enters the vergic sac. Internally (fig. 12) the preputium has two vertical 
pilasters. The vergic sac is long and cylindrical and is enlarged at the 
upper end (VS). The verge (V) is long and narrow, enlarged at the upper 
end, very narrow below where there is a horny stylet (ST). The opening 
of the sperm canal is on the side as in typical Gyraulus. Between the vergic 
sac and the preputium there is a large papilla and below this a swelling 
of the wall of the preputium representing the better-developed muscular 
ring or diaphragm of typical Gyraulus (not shown in the figure). 

Female Organs. The spemiatheca (fig. 6, S) is small, pyriform, and 
connected with the vagina by a duct about as long as the spermatheca 



Subfamilies, Genera, and Subgenera — Recent and Fossil 73 

fSD). The vagina is narrow and about as long as tlie spernuitheca and 
its duct. The uterus and nidamental gland are relatively short and wide 
(U). The oviduct is short (about 0.5 mm.). The junction of the oviduct 
and sperm duct to form the ovisperm duct is shown in fig. 7. The albumen 
gland is squarish in form, longer than wide (about 1 mm. long), and is 
composed of large diverticula. Its duct is long and looped (fig. 9, DA). 

Hermaphrodite Organs. The ovotestis is rather short and is composed 
of Init few club-sha})e(l diverticula arranged in a double row (fig. 6, OT; 
fig. 11). The ovisperm duct is small and tube-like and is longer between 
the seminal vesicle and the ovotestis than between the seminal vesicle and 
the oviduct (fig. 6, SO). Several of the diverticula of the ovotestis were 
filled with ova ready for extrusion (fig. 11). 

Several other species of the subgenus Torquis have been dissected and 
may be compared with parvus. Gyraidus circumstriatus (Tryon) (i)late 17, 
fig. 1, also fig. 4) is similar in form. The prostate has twelve diverticula. 
The spcrmatheca is the same. The duct to the albumen gland is not so long 
( fig. 2) . The penial complex is the same in both species which are of about 
the same size. In Gyraulus vermicularis (Gould) there are sixteen diver- 
ticula in the prostate and ten diverticula in the ovotestis (plate 15, fig. 10). 
The penial complex is somewhat different, the preputium being long and 
cylindrical and the vergic sac very short, only about half as long as the 
preputium. In Gyraidus similaris (F. C. Baker) (plate 18, fig. 1) there are 
nineteen diverticula on the prostate and the ovotestis diverticula are few 
in number. In the penial complex the vergic sac is shorter than the 
preputium. There is a heavy swelling at the upper part of the preputium 
where the papilla and muscular ring are located. A section through the 
penial complex (fig. 3) shows the relationship between the several organs. 
The verge is very long and slender and has a large stylet (fig. 4). The 
junction of oviduct, sperm duct, and ovisperm duct is shown in fig. 2. 

The genitalia of the subgenus Torquis differ from those of typical 
Gyraidus in the form of the seminal vesicle, the fewer diverticula of the 
prostate, and the rounder spermatheca on a shorter duct. In general, how- 
ever, the two groups are very similar in the form and position of the 
genital organs. No figures of the genitalia of the Torquis group have been 
iniblished jireviously; hence no comparisons can be made. 

Respiratory and Renal Systems. The jiseudobranch of Gyraidus parvus 
(plate 17, fig. 8) is flattened, wide, leaf-like, and is pierced by the rectum. 
The pneumostome is very large. In Gyraulus circumstriatus (fig. 3) the 
pseuclobranch is much narrower (the animal was much contracted). In 
Gyraidus vermicularis (plate 15, fig. 8) it is flattened and somewhat tri- 
angular. In Gyraulus similaris (plate 18, fig. 5) it is like that of vermicu- 
laris but the rectum has a slight ridge which was not observed in any of the 
other species examined. In the four species of this group studied there was 
a large, flattened, muscular jiad extending backward from the free portion 
of the pseudobranch to the place where the rectum begins on the intestine. 
Figure 5 on plate 18 and fig. 8 on plate 15 show the form of this pad. The 
rectum pierces this pad as well as the pseudobranch and has its exit (A) 
above the leaf-like pseudobranch. 

The kidney (plate 47, fig. 1, parvus) is very long and narrow (4 mm. 
long, 0.5 mm. wide), the ureter short and recurved. In Gyraidus circum- 



74 The Molluscan Family Planorhidae 

striatus (fig. 2) the kidney is much shorter and wider (less than 2 mm. 
long). In vermicularis it is short and wide as is also the case in similaris. 
Cross sections through the kidney of the four species show a similarity of 
conditions (fig. 5 parvus; fig. 6 circumstriatus ; fig. 7 vermicularis; fig. 9 
similaris). The kidneys in Gyraulus and Torquis differ little in structure. 

Digestive System. The digestive tract shows division into crop, gizzard, 
and pyloris and there is a large blind sac. The intestine does not form a 
posterior loop, as in typical Gyraulus, but crosses over the oesophagus and 
extends forward as in the genus Planorbis. The buccal sac is like this organ 
in typical Gyraulus. 

The jaw (plate 50, fig. 16, parvus) is horseshoe-shaped with many 
small plates as in Gyraulus typical. There are approximately thirty-six to 
forty plates on the jaw of parvus and Gyraulus vermicularis has about 
forty-seven plates (fig. 19). Gyraulus circumstriatus (fig. 22) has a small, 
narrow jaw with about thirty-seven plates. The jaws of Gyraulus (figs. 
17-18) are not as typically horseshoe-shaped as in the subgenus Torquis. 

The radula formula of Gyraulus parvus (Say) is 14-1-14 with 105 rows 
of teeth (plate 69, fig. 3). The center tooth is bicuspid, the cusps not 
reaching the lower margin of the base of attachment. There are 1-6 lateral 
teeth, tricuspid, with spade-shaped cusps. Intermediate teeth (7-8) with 
the ectocone split into two small cusps. The 9th tooth is also transitional 
with the ectocone split into three small cusps. Typical marginal teeth 
(10-13) have the entocone split into two small cusps, the mesocone large 
and spade-shaped, and the ectocone split into three small cusps. 

In Gyrauliis vermicularis (Gould) (fig. 5) the formula is 15-1-15, with 
1-6 laterals, 7-10 intermediates and 11-15 marginals. There are 120-125 
rows of teeth. In Gyraulus similaris (F. C. Baker) (fig. 4) the formula is 
22-1-22 with 1-7 laterals, 8-10 intermediates, and 11-22 marginals. There 
are 130 rows of teeth. Gyraulus circumstriatus (Tryon) has the formula 
14-1-14 with the same number and position of teeth as in parvus. The 
radula teeth of the subgenus Torquis do not differ in general character- 
istics from those of typical Gyraulus. Compare figs. 1, 2 with figs. 3, 4, 5 
on plate 69. 

For the above anatomical data the following specimens were studied : 

Gyraulus parvus (Say), 14 specimens from Winnebago Lake, Wisconsin, Henry Co., 
Illinois, and Meach Lake, Canada, collected by F. C. Baker and A. LaRocque. 

Gyraulus circumstriatus (Tryon), 17 specimens from Wainwright Park, Alberta, col- 
lected by Dr. Swales, and North Star Lake, Wisconsin, collected by F. C. Baker. 

Gyraulus vermicularis (Gould), 10 specimens from Mt. Lake, San Francisco, California, 
and Hat Creek, Bishop, California, both lots collected by Dr. G. D. Hanna. 

Gyraulus .siyiiilaris (F. C. Baker), 17 specimens from Smartweed Lake, Toland, Colo- 
rado, collected by Dr. Frank Smith. 

Geographical Distribution. The subgenus Torquis is found throughout 
North America from Mexico northward. It is also apparently represented 
by Gyraulus santacruzensis Germain from the Island of St. Croix, West 
Indies. Gyraulus laevis Alder, a common species of Europe, also belongs to 
this subgenus. Some of the other species listed under the distribution of 
typical Gyraulus may belong to Torquis, but not enough material is avail- 
able for study to confirm this suggestion. 



Subjcunilics, Goiera, and Subgenera — Recent and Fossil 75 

Species Considered as Valid. The American species included in tliis 
subgenus are: 

Gyraiilus (Torqids) aeruginosus GtjmuJus (Torquis) parvus (Say) 

Morelct Gyrauhts (Turquis) mntacruzensis 

Gyrauluti (Torquis) arizonensis (Germain) 

Pilsbry and Ferriss Gyrnuluj< (Torquis) siniildris 

Gyraulus (Torquis) allissimus (F. C. Baker) 

(F. C. Baker) Gyraulus (Torquis) vcrDiicularis 

Gyraulus (Torquis) carus (Gould) 

Pilsbry and Fcrriss (hjrnulus (Torquis) vermicukiris 

Gyraulus (Torquis) circuinstrint as hendcrsoni Walker 

(Try on) 
Gyra ul us ( Torq uis ) circ u ni s[ ria tus 

u'nlkcri Vanatta 

Geological Distribution. Torquis apparently dates geologically from 
the Oligocene period. Torquis siliceus Pilsbry and Brown, Oligocene of 
Dry Hill, Antigua. 

Remarks. Except for some small details in genitalia, referred to on a 
])revious page, the subgenus Torquis is similar in anatomical details to 
typical Gyraidus. It is, however, a convenient name for the smaller species 
with 'reamed out' left side, like parvus and vermicularis, which have nar- 
rower and smoother whorls than the species of typical Gyraulus, like alhus 
and de flee tus. 

Genus ARMIGER Hartmann, 1840 

Type by designation of Hartmann in 1842, Nautilus crista Linn. 

1840. Armiger Hartmann, Syst. ubers. Em-op. Gatt., table. 

1842. Armiger Hartmann, Erd-und Siiss. Gasterop., V, pp. 172, 219. Tyjie Armiger 
cristatus Drap. = Nautilus crista Linn. 

1847. Nautilus Gray, Proc. Zool. Soc, p. 181. Type Turbo nautilus Linn. 

1850. Nautilina Stein, Leben. Schneck. und Musch. Berlins, p. 81. Ideogenotype Pln- 
norbis nautilus Stein = Planorbis cristata Drap. Type designation by Lind- 
holm in 1926. 

1885. Armiger Westerlund, Fauna Palaearc. Reg., V. i*. 65. No type cited. As sub- 
genus of Planorbis. 

1902. Aryniger We.sterlund, Rad. Jugoslav. Akad., 151, p. 121. Type Turbo nautilus 

Linn. As subgenus of Planorbis. 

1903. Spiniformis Germain, Bull. Soc. Sci. Nat. Quest France, ii. III, p. 204. Vide 

Germain, 1931. 
1905. Armiger Dall, Ala.ska Moll., pp. 83, 86. Type Planorbis crista (Linn.). As sec- 
tion of subgenus Gyraulus. 
1918. Armiger W.alker, Miscel. Contr., Mus. Zool., Univ. Mich., No. 6. pp. 13, 94. 

Tj'pe Planorbis crista (Linn.). As section of subgenus Gyraulus. 
1923. Armiger Germain, Rec. Ind. Mus., XXI, pp. 8, 153. Type Plariorbis crista 

(Linn.). As subgenus of Planorbis. 
1923. Armiger Wenz, Fossil. Cat., Pars 22, p. 1625. Genotype Gyraulus (Armiger) 

crista (Linn.), As subgenus of Gyraulus. 
1926. Armiger Lindholm, Archiv. fiir Mollusk., 58 year. Heft 6, p. 253. Monogenotype 

Armiger cristatus T)rap. = Planorbis crista (Linn.). As genus on conchological 

grounds. 

1928. Armiger F. C. Baker, Fresh-water Moll, of Wisconsin, I, p. 385. Type Nautilus 

crista Linn. As subgenus of Gyraulus. 

1929. Armiger H.\As, Trab. Mu.seo Cien. Nat. Barcelona, XIII, p. 386. Type evidently 

Nautilus crista Linn. As genus. 



76 The Molluscau Family Plauorbidae 

1929. Armiger Odhxer, Die Mollusk. Fauna Takern, p. 22. Type Armiger crista 

(Linn.). As genus on anatomical grounds. 
1931. Artniger, Germ.^in, Moll. terr. fluv. de France, II, j). 540. Type Plonorbis crista 

(Linn.). As subgenus of Planorbis. 
1931. Armiger Thiele, Handbuch, IV, Teil 2, p. 481. Type Anisus (Armiger) crista 

(Linn.). As subgenus under Anisus. 
1935. Armiger A. Soos, Allat. Kozleni., XXXII, p. 30. As subgenus of Gyraulus. No 

type indicated. 

Shell (i)late 76, fig. 6). Ultradextral, small, with few rapidly increasing, 
costate whorls, the costae usually projecting at the periphery. The general 
form is like that of Gyraulus. 

Animal. External form like that of Gyraulus. 

ANATOMICAL CHARACTERISTICS 
PLATE 18 

GENITALIA. Male Organs (plate 18, fig. 7) . Seminal vesicle (SV) with 
very few large glands or diverticula. Sperm duct 1.5 mm. long, bent upon 
itself in a loop posterior to the prostate. Prostate 0.5 mm. long, consisting 
of thirteen long, cylindrical diverticula placed on a separate prostate duct. 
The free portion of the prostate duct is very short. Vas deferens a long 
(1 mm.), small duct. 

Penial complex (fig. 7) with a vergic sac one and one-half times as long 
as the preputium. The vergic sac is enlarged at the end w^here the vas 
deferens enters it as an enlarged tube. There is one retractor muscle (RM). 
The preputium is of larger diameter than the greater part of the length of 
the vergic sac. 

Internally (fig. 9) the j^enial complex is formed like that of Gyraulus. 
There are two }ulasters, a dependent papilla (D), and also a muscular ring 
or diaphragm (not shown in figure). The verge (V) is elongated, cylin- 
drical, tapering gradually to the end, which does not bear a horny stylet, 
as in Gyraulus, but a small, pointed fleshy papilla (fig. 10, PA, fig. il, PA). 
The opening of the sperm canal is just above this papilla at the end of 
the verge, in the center and not at the side as in Gyraulus (figs. 10, 11, SC). 

Female Organs, The spermatheca (S) is long and pyriform in shape, 
taj^ering gradually to the short, wide vagina (VG) , the duct being very 
short. The uterus (U) and nidamental gland are wide, the uterus short and 
the gland rather long. The oviduct (OD) is short and greatly swollen below 
the junction with the sperm duct to form the ovisperm duct. The albumen 
gland (fig. 8) is large (1 mm.), elongated and composed of large gland 
cells. It is joined to the large, bulbous carrefour (CF) by a long, very fine 
duct (DA). The carrefour connects with the oviduct. The intestine ex- 
tends the whole length of the albumen gland which covers the greater jmrt 
of the intestine. The space occupied by this organ is shown in the 
figure (AL). 

Hermaphrodite Organs. The ovotestis (OT) consists of many club- 
shaped diverticula placed in a double row. The ovisperm duct (SO) is 
twice as long between the oviduct and the seminal vesicle as between that 
organ and the ovotestis. 

No figure of the whole genitalia of Armiger was available before the 
publication of A. Soos's paper in 1935. His figure (1935, p. 28) differs in 
several respects from the ones here presented. The prostate has nine 



Subfamilies, Genera, and Subgenera — Recent and Fossil 77 

divertieuhi which upi)ear widely fjpaeecl while there were thirteen crowded 
diverticula in the specimens personally examined. The separate prostate 
duct is not shown in Soos's figure. The spermatheca in Soos's figure is also 
on a longer duct. The penial complex differs in several respects. 

In 1929 (p)). 22, 30) Odhner called attention to the absence of a stylet 
in Armigcr, figured the verge of Anniger crista to show the absence of the 
stylet and the i)resence of a small penial i)apilla. This is, apparently, the 
first indication of this anatomical difference between Armiger and 
Gyraulus. Odhner noted a difference in the size of the teeth and formula of 
crista, those from the Takern having much smaller teeth than specimens 
from near Stockholm. The formula, also, was only 11-1-11 while the 
larger form has a formula of 14-1-14. 

Germain (1931, ii. 540) says 'Appareil genital comme chez les especes 
du sous-genre Gyraidus.' But this is not the case. There is no stylet at 
the end of the verge and the opening of the sperm canal is at the center 
beside a small papilla and not at the side above a stylet as in Gyraulus. 
The seminal vesicle is also different in form of glands. These differences in 
anatomy are sufficient to remove Armiger as a subgenus of Gyraulus and 
indicate its right to full generic rank. The genitalia of Armiger and Torquis 
may be compared on i^late 18, where the difference in the structure of the 
termination of the verge is i)lainly indicated. 

Respiratory and Renal Systems. The pseudobranch (plate 18, fig. 6) 
is broadly triangular, leaf-like. The rectum is a large tube bordering the 
upper side of the pseudobranch and the anus is above the pseudobranch. 

The kidney (plate 47, fig. 20) is short and wdde, somewhat resembling 
the kidney of Gyraidus vermicularis (fig. 3). A section through the kidney 
near the middle (fig. 21) shows it to be flattened, convex above, with the 
veins near the center of each side of the oval lumen. The section is also 
similar to that of Gyraulus vermicidaris (fig. 7). 

Digestive System. In the region of the stomach (plate 48, fig. 15) there 
is a distinct division into crop, gizzard, and pyloris. The intestine makes a 
loop forward and then backward under the oesophagus. It bends around 
the liver and turns forward, ending in the rectum on the pseudobranch. 
The stomach region resembles that of Gyraulus (fig. 13). The buccal sac is 
like that of Gyraidus. 

The jaw (plate 50, fig. 20) is narrow and characteristically horseshoe- 
shaped with the lateral processes elongated. There are twenty-two plates in 
the upper or superior jaw and fourteen to sixteen plates in each of the side 
jaws. The jaw most nearly resembles that of Gyraidus circumstriatus (fig. 
22) except that it bears a larger number of plates. 

The radula formula is 16-1-16 with 150 rows of teeth. The center tooth 
is bicusj^id and resembles that of Gyraulus vermicularis (fig. 5). The 
laterals are four-cuspid (1-9), the intermediate teeth (10-11) five-cuspid, 
and the marginals (12-13) six-cuspid. The outer marginals are vestigial. 
The teeth resemble those of Gyraulus except that there is always an 
accessory cusp above the ectocone, even in the lateral teeth. 

For the above anatomical data ten specimens were dissected, collected 
from a swamp on University Bay, Lake ]\Iendota. near [Madison, Wiscon- 
sin, by Dr. J. P. E. [Morrison. These represent the variety i}nbricatus. 
Typical crista from a pond in Krolikarnia, a suburb of Warsaw, Poland, 
collected by A. Jankowski. provided most of the anatomical data. 



78 The Molluscan Family Plauorbidae 

Geographical Distribution. Armiger is Palearctic in distribution, oc- 
curring in the northern United States and Canada, northern Europe and 
Asia. Armiger crista is reported from the trans-Mediterranean region, 
from Algeria, Tunis, etc. A species {Armiger annandalei Germain) has been 
described from eastern Asia. The genus contains several forms which 
should probably rank as species. 

Geological Distribution. According to Wenz (pp. 1632-1633) Armiger 
is first known from the Middle Miocene period. 

Species Considered as Valid. The only species definitely assigned to 
this genus in the present volume are: 

Armiger crista (Linn.) Armiger imhricatus (Miiller) 

Armiger crista spinulosum Armiger annandalei (Germain) 

(Clejsin) 

Remarks. By the form of the penial complex tliis group is distinct from 
Gyraulns and should be considered as of full generic rank. L. Soos (1917) 
and A. Soos (1935) list it as a subgenus of Gyraulus, but the lack of a 
penial stylet removes it from that group. Lindholm (1926) considers it a 
genus. Thiele (1931) considers it a subgenus of Anisus. Odhner (1929, 
p. 30) gives the group full generic rank on the basis of the lack of a stylet 
on the verge which is characteristic of Gijraulu^^. A good figure of the verge 
of Armiger crista, showing the small penial jjapilla at one side of the sperm 
outlet, is shown (fig. 10). Haas (1929, p. 386) considers Armiger a distinct 
genus. 

Odhner (1929, pp. 20, 21, 30) states his belief that Armiger represents 
a stage in the evolution of Gyraulus. He found young Gyraulus borealis of 
two whorls without a stylet on the verge while those of three and one-half 
whorls had a well-developed stylet. Specimens of Gyraulus laevis of three 
whorls had a stylet. From these observations he concludes that the develop- 
ment of the stylet (penisstachel) may be checked in the later fall, possibly 
through some unfavorable climatic condition. Haas, in a review of this work 
( 1930, p. 20) does not fully agree with Odhner, believing that more study 
should be given the subject before conclusions are made. This is undoubt- 
edly true, but the subject is one of great interest and dissections should be 
made of many species at different ages to determine whether the stylet is 
absent in young and immature Gyraulus. It has been present in all speci- 
mens personally examined, but these were either full grown or nearly 
full grown. 

This group of small snails is highly variable specifically and a number 
of names have been bestowed upon the variations. Two forms appear dis- 
tinct enough to rank as species, crista (Linn.), with strong ribs projecting 
from the shell, and imbricatus (Miiller), in which no ribs project from the 
shell. Armiger spinulosum (Clessin) is i^robably a race of crista Linn. 
Another species in eastern Asia has been named annandalei by Germain. 

The value of recognizing subgenera for these variations may be ques- 
tioned seriously. In 1922, Dybowski and Grochmalachi erected three sub- 
genera based on spiny variation in Armiger: Nautiloarmiger, Cristoarmi- 
ger, and Atropoarmiger (vide Lindholm, 1926, p. 24). 

There appears to be some variation in the genitalia and also in the 
radula. Odhner found the formula to be 11-1-11 and 14-1-14 in crista from 
two localities and the writer obtained the formula 16-1-16 from crista 



Subfmnilies, Genera, and Subgenera- — Recent and Fossil 79 

collected in Poland. These differences may all be individual. The group 
merits additional anatomical study. 

(k'nus TAPHIUS H. and A. Adams, 1855 

T.ype by original designation Planorbis nndecolus Orb. 

1855. Taphius H. and A. Ad.\ms, Genera, II, p. 262. Type Planorbis andecolus Orb. 

1870. Taphius D.all, Ann. N. Y. Lye. Nat. Hist., IX, p. 351. Tj'pe Planorbis andecolus 

(H. and A. Adams, error for Orb.). As subgenus of Planorbis 

1883. Taphius Fischer, Man. de Conch., \). 507. Type Planorbis andecolus Orb. As 

section of Planorbis 

1884. Taphius Tryon, S. and S. Conch., Ill, p. 106. Type Planorbis andecolus Orb. As 

subgenus of Planorbis 

1886. Taphius Clessin, Syst. Conch. Cab., XVII. p. 33. Type Planorbis andecolus 
Orb. As subgenus of Planorbis 

1899. Taphius Martens, Biol. Cent. Amer., Moll., p. 396. Mentions Planorbis sub- 
pronus Martens. As subgenus of Planorbis 

1905. Taphius D.\ll, Alaska Moll., p. 81. Type Planorbis andecolus Orb. As sj'nonym 
of Helisoma 

1921. Taphius Germain, Rec. Ind. Mus., XXI, pp. 7, 62. Type Planorbis andecolus 
Orb. As subgenus of Planorbis 

1924. Taphius Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 49, plate 4. Variation of Pla- 
norbis andecolus Orb. 

1930. Taphius H. B. Baker, Oc. Papers, Mus. Zool. Univ. Mich., 210, p. 43. Monotype 

Planorbis andecolus Orb. As genus 

1931. Taphius Thiele, Handbuch, Part 2, p. 479. Type Planorbis andecolus Orb. As 

.-section of Planorbis 

Shell (plate 77, figs. 13-15). Sinistral, whorls few, raindly increasing 
in diameter, the body whorl wide and much enlarged; spire greatly de- 
pressed below the level of the body whorl, the spire whorls bluntly angu- 
late; umbilical side flattened; all the whorls visible and nearly in the 
same plane; aperture large, expanded; no lamellae within the aperture. 
Animal. The characteristic of the animal and its anatomy have not 
been described. 

Geographical Distribution. South and Central America from southern 
Mexico to Peru and Bolivia. 

Species Considered as Valid. Only five species are here referred to 
Taphius. 

Taphius andecolus (Orb.) Lake Titicaca, Peru 
Taphius moiitanus (Orb.) Lake Titicaca, Peru 
Taphius titicacensis (Clessin) Lake Titicaca, Peru 
Taphius pronus (Martens) Venezuela 
Taphius s}ibpronus (Martens) Mexico 

Geological Distribution. Not definitely known. T(tph{}(s pronus has 
been found fossil in Lake Valencia, Venezuela, probably of Pleistocene age. 

Remarks. The systematic position of the genus Taphius is greatly in 
doubt because its anatomy is unknown. Some of the species, as pronus and 
subpronus, resemble certain species of Tropicorbis and Taphius may be 
another genus of Planorbidae peculiar to both Central and South America. 
Typical andecolus bears a striking resemblance to the tyi')ical group of 
Helisoma and Dall (1905) made Taphius a synonym of that group. 
Cermain (1921) makes it a subgenus of Planorbis allied to Helisoma. 



80 The Molluscan Family Planorbidae 

Pilsbry (1934, p. 47) associates Taphius with Helisoma and refers 
Taphius pronus to Helisoma together with caloderma, but pronus certainly 
does not resemble any form of Helisoma, rather is it allied to Tropicorbis. 
What the group may be and where it may be placed can only be deter- 
mined by an anatomical study. With our present limited knowledge, it 
seems best to regard Taphius as a genus related to Tropicorbis. An excel- 
lent account of the shell variation of Taphius andecolus, accompanied by 
a good plate, is given by Pilsbry (1924, p. 49, plate 4). 

Genus TROPICORBIS Pilsbry and Brown, 1914 

Type by original designation, Planorbis liebmanni 
Dunker (= Pkmurbis orbiculus Morelet) 

1880. Gyrorbis Fischer and Crosse, Etudes Moll, terr-fluv. Mex. et Guat., II, p. 70 
(non Gyrorbis Fitz., 1833). Example Planorbis orbiculus Morelet. 

1884. Menetus Tryon (non H. and A. Adams), S. and S. Conch., iii, ]>. 106. Example 
Planorbis heloicus Orb. 

1899. Planorbula Martens (part), Biol. Cent. Amer., Moll., p. 398. Includes Planorbis 
obstructus Morelet and Planorbis dcntiens Morelet, now referred to Tro- 
picorbis. 

1899. Menetus M.artens (part) (non H. and A. Adams), o\^. cit., \). 390. Includes 
species now referred to Tropicorbis. 

1914. Tropicorbis Pilsbry and Brown, Proc. Acad. Nat. Sci. Phil., 66, p. 212. Type 
Planorbis liebmanni Dunker. As section of Planorbis. 

1921. Tropicorbis Germain, Rec. Ind. Mus., XXI, p. 91. Type incorrectly given as 
Planorbis tnaya Morelet. As subgenus of Planorbis. 

1923. Tropicorbis Wenz, Fossil. Cat., Pars 22, p. 1627. Genotype Gyrauhis (Tropicor- 
bis) liebmanni (Dunker). As subgenus of Gyraulus. 

1930. Tropicorbis H. B. Baker, Oc. Papers Mus. Zool. Univ. Mich., No. 210, p. 43. 

Type Planorbis liebmanni Dkr. As genus. 

1931. Tropicorbis Thiele, Handbuch, IV, Teil 2, p. 480. Type wrongly stated to be 

Planorbis maya Morelet. As section of Planorbis. 
1934. Tropicorbis Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 52. Type Planorbis 

liebmanni Dunker. As genus. Anatomy described. 
1936. Tropicorbis F. C. Baker, Nautilus, 49, p. 104. Anatomy of Planorbis obstructus 

Morelet and Planorbis havanensis Orb. described. As genus. 

1939. Oh^tructio H.\as. Zool. Ser. Field Mus. Nat. Hist. XXIV, p. 99. Type by original 

designation Planorbis janeiremsis Clessin. As subgenus of Planorbis. 

1940. Tropicorbis F. C. Baker, Nautilus, LIII, p. 106. As genus. 

1941. Obstructio Haas, Nautilus, 55, p. 31. 

Shell. Of medium size, idtradextral, orbicular, of few whorls which may 
increase regularly in diameter (plate 77, figs. 7-9 orbiculus) or the body 
whorl may increase rapidly in diameter (plate 77, figs. 10-12, pallidus) ; 
whorls in view equally on both sides, somewhat overlapping on the left 
(spire) side; aperture unarmed or with one large parietal lamella with a 
small infraparietal below it, and four lamellae within the outer lip. The 
labial lamellae differ principally from those of the genus Planorbula in 
having the lower palatal lamella pointing slightly downward on the left 
side while in Planorbula this lamella always points upward, in the group 
Hcddemanina the upward end forming a vertical and transverse lamella 
combined. The basal lamella in Planorbula is normally more massive and 
is, in some species, distinctly curved (plate 76, figs. 7, 8, 9). 



Sub fcun Hies, Genera, and Suhijeuera- -Recent and Fossil 81 

Animal. When in locomotion the foot is rather long and narrow, 
rounded before and tapering to a point behind. The tentacles are very long 
and filiform and the eyes are large, black, and conspicuously placed at the 
inner base of the tentacles (plate 78, figs. 3, 4). The velar area is well 
developed. When at rest (plate 70, fig. 4, Tropicorhu havanensis) the foot 
may be hunched up, rounded, and even the tentacles may be drawn back- 
ward. The Tropicorbis group is noteworthy for the peculiar pigmentation 
observed in some species, this consisting of dark, blackish or brownish, 
markings which show plainly through the shell (plate 78, figs. 3, 4, Tropi- 
corbis nigrilabris (Lutz) ), and are particularly plain when the animal is 
removed from the shell (plate 12, fig. 5, T. havanensis (Pfr. ) ). These some- 
times show on the base, through the shell, as dot-like markings (plate 70, 
fig. 4, T. havanensis). 

ANATOMICAL CHARACTERISTICS 
PLATE 12 (Tropicorbis havanensis) 

GENITALIA. Male Organs (fig. 11) . Seminal vesicle (SV) of greater 
diameter than the ovisperm duct. It is beset with numerous protuberances 
or glands many of which have the form of club-shaped diverticula. They 
vary in size anteriorly, the larger vesicles being nearer the ovotestis. The 
whole seminal vesicle is about 2 mm. long. The sperm duct is over 5 mm. 
long and is very narrow. It is peculiarly enlarged at the junction of the 
oviduct and sperm canal and might be considered a carrefour, but that 
feature is attached to the female system and is a small swelling into which 
the albumen duct enters (fig. 11, CF). See figs. 7, 8, CF. 

The I'jrostate (PRS) is very long (3.5 mm.) and bears about fifty short, 
sac-like diverticula. These are placed on a separate duct, the prostate duct, 
the free portion of which is very short and ciuickly joins the vas deferens. 
A cross section through the prostate (fig. 9, PD, SPD) shows the relation- 
ship between these two separate ducts. The vas deferens (VD) is moder- 
ately long (3.5 mm.) and is a small tube throughout its length except that 
it is slightly enlarged where it enters the vergic sac (fig. 1, VD). 

The penial complex (fig. 11) is much elongated; the preputium (PR) 
is cylindrical and slightly longer than the vergic sac ( VS) . In another 
specimen (fig. 10) the preputium and vergic sac were more nearly equal in 
length and the upper part of the vergic sac was slightly enlarged. The vergic 
sac is always of less diameter than the preputium. The retractor muscles 
(RIVI) are somewhat complicated, there being three branches all con- 
nected by cross muscles. There are also several small muscles below the 
retractor muscles which are attached to the mantle and not to the colu- 
mella muscle. These may be what we have called supporting muscles. There 
are several series of muscles on the opposite side of the penial complex 
which we have called supporting muscles (SM). These are attached to 
the upper j^art of the neck. The upper set, which have small branches, may 
also help in retracting the penial complex following coitus. 

Internally (fig. 1) the preputium has two or more pilasters. There is a 
heavy muscular ring or diaphragm which separates the preputial cavity 
from the vergic space (fig. 1, D, fig. 2). This apparently takes the place 
of the papilla in Gyraidiis, but there is no second ring below this ring, as 
there is in Gyraulus. The verge (V), very long and cylindrical, ends in a 



82 The Molluscan Family Planorhidae 

small papilla and the sperm canal has a central outlet (fig. 3). The walls 
of the vergic sac are thin but those of the preputium are rather thick. 

Female Organs. The spermatheca (S) is pear-shaped and less than 
1 mm. long. The spemiathecal duct is longer than the spermatheca, very 
narrow, and enters the short vagina (VG) near the female opening. The 
uterus (U) is narrow and slightly longer than the spermatheca and its duct. 
The nidamental gland (NG.) is long and narrow (about 3 mm. long) and 
of larger diameter than the uterus. The oviduct (OD) is about 2 mm. long 
and smaller in diameter than the nidamental gland but much wider than 
the sperm duct. The albumen gland is short, somewhat pear-shaped with 
large gland cells (fig. 6). It lies over the intestine, one loop of which 
passes through a trough-like space on the under side of the albumen gland. 
The junction between the oviduct, sperm duct, and ovisperm duct, together 
with the albumen gland connections, are shown in figs. 7 and 8. 

Hermaphrodite Organs. The ovotestis (OT) consists of many club- 
shaped diverticula placed in a double row. The ovisperm duct is very short 
between the seminal vesicle and ovotestis but three times this length be- 
tween the seminal vesicle and the oviduct. The duct is a narrow tube. 

Two other species of Tropicorbis have been dissected by the writer. 
Tropicorbis nisei (Dunkerl (plate 13, fig. 9) has twenty-four diverticula on 
the prostate and Tropicorbis obstructus (]\Iorelet) has eighteen diverticula 
on its i)rostate. The penial complex is about the same in the three species. 
Some of the diverticula of the prostate are folded over at the end in riisei 
(figs. 4, 5). The retractor muscle complex is complicated in riisei but quite 
simple in obstructus. The spermatheca is rounder and less pyriform in 
riisei and obstructus and the ducts are longer than in havanensis (compare 
the figures). In obstructus a number of the diverticula of the ovotestis 
contained eggs almost ready to be discharged (plate 13, fig. 3). The junc- 
tion of the prostate duct and the sperm duct to form the vas deferens is 
shown in fig. 8 iriisei). 

Pilsbry (1934, p. 53) has figured the genitalia of Tropicorbis pallidus 
(C. B. Adams), from Bolivar, near Santa Alarta, Colombia. This figure 
differs in a few respects from the genitalia of riisei, havanensis and 
obstructus as figured in this volume. There are twelve long and somewhat 
irregular diverticula on the prostate. The penial complex shows a very 
long and narrow vergic sac, considerably longer than the preputium. The 
verge appears as in the other species studied. There is one retractor muscle 
as in obstructus. 

It is evident from the knowledge afforded by the four species of which 
the anatomy is known that there is considerable variation in the details 
of structure of the genus Tropicorbis. The prostate, particularly, may bear 
as many as fifty diverticula {havanensis) or as few as twelve diverticula 
(paUidu.s) . The penial complex may have the vergic sac shorter than the 
preputium {havanensis) or much longer than the preputium {pallidus). 
There is complete agreement, however, in the long, narrow verge with 
tenninal oj^ening, the lobulate seminal vesicle, the long and narrow oviduct, 
nidamental gland, and sperm duct, and the rounded or pear-shaped 
spermatheca on a long duct. It is desirable that the genitalia of the type 
species {orbicidus = liebmanni) be known. It is believed to be like havan- 
ensis, a related species. Hundreds of shells of orbiculus have been seen 
but no material containing the animal has been available. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 83 

Respiratory and Renal Systems. The pseiidobranch (of havanensis, 
plate 12. fig. 4 1 is a thin, leaf-shaped, fleshy organ doubled or folded upon 
itself. The rectum (Rl lies above the pseiidobranch and has a conspicuous 
crested ridge extending nearly its whole length, ending some distance above 
the anus. There is a large pneumostome (PS). In riisei (plate 13, fig. 10) 
the folded nature of the pseiidobranch is better shown as is also the crested 
ridge. The crest is present in all species examined. Pilsbry's figure of the 
pseudobranch of pallidus (1934, p. 53. B» shows a simple folded pouch. In 
his figure C. the pseudobranch is figured as much elongated. This appears 
to be a pathologic condition. 

The kidney (plate 46, fig. 11, riisei) is rather long (about 2.5 mm.), 
the ureter sharply reflected. A cross section near the middle (fig. 12) shows 
the kidney to be rounded with the lumen rounded, the two veins being at 
the lower corners of the section. There is no ridge on the kidney but there 
is a distinct vertical ridge in the mantle to the left of the kidney. A cross 
section of the kidney of havanensis (fig. 13) shows that in this species this 
organ is much more compressed and much wider than in riisei; the central 
lumen is irregularly oval with the two veins placed below the lumen at the 
outer ends of the section. Of pallidus, Pilsbry says 'The kidney is long, 
band-like, and flat, with no trace of a superposed ridge' (p. 52). 

Digestive System. Stomach region with distinct division into crop, 
gizzard, and pylons. There is a large blind sac. The intestine makes a 
backward loop around the liver and extends forward, the rectum ending 
near the pseudobranch. The digestive organs are alike in all species 
examined. The buccal sac is pyriform with a large and conspicuous radula 
sac which protrudes from the posterior end of the buccal sac as a rounded 
projection. This sac is longer in obstructus than it is in riisei. The salivary 
glands are cylindrical, longer than the buccal sac. and joined behind, as 
in other groups of the Planorbinae. 

The jaw of riisei (plate 50, fig. 12) is composed of three pieces, a wide 
and low superior part, finely striated along the face, and two lateral pieces 
which assume the form of a question mark. These are enlarged at their 
junction with the superior jaw and taper to a point at the lower end. The 
jaw of obstructus is similar to that of riisei (fig. 11). H. B. Baker has 
described the jaws of pallidus and kiihnianus (1930, pp. 47, 48). The jaws 
of Tropicorbis are unlike those of the other genera of Planorbinae (ex- 
cepting Australorbis) and resemble those of the subfamily Helisomatinae. 

The radula formula of havanensis (plate 68, fig. 8) is 19-1-19 or 
20-1-20 with 109 to 112 rows of teeth. The central tooth has a broad base 
of attachment and is bicuspid, the cusps spade-shaped and reaching to the 
lower margin of the base of attachment. Laterals (1-6) squarish with three 
cusps, the entocone larger than the mesocone and ectocone. The 6th tooth 
has a small interstitial cusp on the entocone and two very small cusps 
above the ectocone. The 7th tooth is an intermediate, the entocone broken 
up into four small cusps and the ectocone with two small cusps on the 
outer edge above. The 8th to the 16th or 17th teeth are marginals (8, 10, 
12), the reflections becoming very long and narrow, with an entocone of 
four or five small cusps, a single spade-shaped mesocone, and four to six 
or seven small cusps on the outer edge representing the ectocone. The 
marginal teeth become narrower toward the edge of the membrane. 
The outer three marginals are vestigial and are without denticula- 
tions. The central teeth of the different rows vary in width at the upper 



84 The MoUuscan Family Planorbidae 

part of the tooth. The first thirty-four rows measure 5.4 microns, rows 35 
to 89 measure 6 microns and rows 90 to 109 measure 5.4 microns. All 
central teeth examined exhibited this variation in width. 

In riisei (plate 68, fig. 6) the formula is 18-1-18 with 105 rows of teeth. 
The center tooth is like that of havanensis but the cusps do not reach the 
base of attachment. There are four lateral teeth. The 5th and 6th teeth are 
intermediate with interstitial cusps between the entocone and ectocone and 
small cusps above the ectocone (figs. 7, 5, 6). Seven to twelve are typical 
marginals with a variable number of small cusps, as in havanensis. The 
15th to 18th teeth are vestigial. The center teeth vary in width as in 
havane7isis, but the teeth are somewhat smaller. 

In obstructus (plate 68, fig. 7) the formula is 19-1-19 and there are 124 
rows of teeth. There are seven tricuspid laterals, the 8th tooth is inter- 
mediate, modified only on the entocone, and there are nine marginals 
becoming narrower toward the edge of the membrane. The outer marginals 
are vestigial. The center tooth varies in width as in the other species. 

H. B. Baker (1930, plate 28, fig. 8) figures the radula of pallidus from 
Bolivar, Colombia. The formula is 18-1-18 with five laterals and there are 
106 rows of teeth. The radula of kiihncrianus is described on page 47 of 
the same paper. The formula is 19-1-19, with six laterals and 106 rows of 
teeth. Thus the radulae of five species of Tropicorbis are known; havan- 
ensis, which is nearest to orbiculus i^licbmanni) , the type of the genus, 
obstructus, riisei, pallidus, and kiihnerianiis. These cover fairly well the 
different variations of the species of the genus. 

The material personally examined is as follows: 

havanensis. New Orleans. Collected by Dr. E. C. Faust; 10 specimens 

riisei. Barceloneta, Puerto Rico. Collected by Dr. W. A. Hoffman; 12 specimens 

obstructus. New Orleans. Collected by Dr. E. C. Faust ; 10 specimens. 

Geographical Distribution. The genus Tropicorbis is one of the most 
widespread of any group of American Planorbidae. From Louisiana and 
Texas in the United States, it extends southward through Mexico and 
Central America into South America as far south as the Argentine Re- 
public, a distance of about 7.000 miles. The group is also found in many 
of the islands of the West Indies. In number of species represented, it out- 
ranks any other group of the family found in America except Hclisoma, 
upward of thirty-three species and races being now recognized (see a later 
page for the list of species). 

Geological Distribution. Oligocene or Lower Miocene to Recent time. 

Remarks. The genus Tropicorbis presents some puzzling features of its 
anatomy which render its systematic position debatable. The nature of the 
prostate, with many diverticula in a single row, on a separate prostate 
duct, places the genus in the subfamily Planorbinae. The kidney is also 
like other members of this subfamily. The penial complex differs from that 
of Anisus and Gyraulus in lacking a penial stylet. The jaw is quite differ- 
ent and resembles this organ in Helisomatinae and Planorbulinae. The 
teeth of the radula also differ in having interstitial cusps on the inter- 
mediate and marginal teeth. Pilsbry (1934, p. 53) remarks that the group 
resembles Gyraulus but differs in the unarmed verge and the different jaw 
and marginal teeth. All points considered, it would seem that its place is 
with the Planorbinae, the largest number of characteristics agreeing with 
those of this subfamily. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 85 

Some of tlie species of Tropicorbis have been heretofore placed in the 
genus Planorbula because of the presence of lamellae within the aperture. 
These lamellae have the same general position in the two groups but the 
lower palatal lamella in Planorbula points upward while in Tropicorbis it 
points slightly downward. The basal lamella is also usually more massive 
in Planorbula than in Tropicorbis (plate 76, figs. 7, 8, 9). Planorbula, how- 
ever, has a very different form of genitalia which removes it from 
the Planorbinae and places it, witii Menctus, in a separate subfamily, 
PIanorl)ulinae. 

The relationshij) between the South American Tropicorbis and certain 
species in Africa is quite remarkable and has been emphasized by Pilsbry 
(1934, p. 54). Tw^o African species (adowensis and pfcifferi) have been 
dissected and the genitalia are very similar to the same organs in Tropi- 
corbis. The African forms may be placed in Afroplanorbis of Thiele, at 
least, until more is known about other species of the African fauna. This 
relationship is discussed at greater length under the description of the 
genus Afroplanoi'bis. 

\\\u\e the anatomy of the several group forms is similar, there are 
variations in the shell which seem to warrant a division of the genus into 
three subgenera or sections. These are indicated below. 



Subgenus TROPICORBIS SS. 

Type Planorbis orbiculus Morelet 

Shell orbicular, the whorls increasing gradually in diameter, the last whorl 
not notably expanded. Apertural lamellae never present at any stage of 
growth. 

Subgenus OBSTRUCTIO Haas, 1939 

Type by original designation, Plauorbis jancircnsis Clessin 

Shell orbicular, whorls increasing slowly in diameter. Aperture with 
lamellae during some stage of the growth of the shell (plate 76, fig. 7) . 

Subgenus LATEORBIS F. C. Baker, New Subgenus 
Type F^lanorbis pallidas C. B. Adams 

Shell with whorls rapidly increasing in diameter, the body whorl notably 
enlarged. Aperture never with lamellae. 

Species Considered as Valid. The species and races believed to group 
under the three subgenera of Tropicorbis are tabulated below. 



TROPICORBIS 

orbiculus (Morelet) 
may a (Morelet) 
havaneiisis (Pfeiffer) 
philipjnanus (Danker) 
heloicus (Orbigny) 
tepicensis (Martens) 
gracilcntus (Gould) 
peregriniis (Orbigny) 
chile nsis (Clessin) 
77}eridaensis (Preston) 
bourcardianus (Preston) 
ce7itimetralis (Liitz) 
fieldi (Tryon) 



OBSTRUCTIO 

jnneiren.sis (Clessin) 
denticns (Morelet) 
d('ntie7is ca7i7iarum 

(Morelet) 
obstructus (Morelet) 
ob>itructu>< donbilli 

(Tristram) 
obstruct)is auodontus 

(Pilsbry) 
dentifcrus (C. B. Adams) 
deciivis (Tate) 
paparyensis (F. Baker) 
nigrilabris (Lutz) 
albica7is (Pfeiffer) 



LATEORBIS 
pallidus (C. B. Adams) 
nisei (Dunker) 
straniiiieus (Dunker) 
pete7iensis (Morelet) 
isthmicus (Pilsbry) 
decipie7ii< (C. B. Adams) 
pedri7ius (Miller) 
cano7iicus (Cousin) 
irigyrus (Philippi) 



86 The Molluscan Family Plaiwrbidae 

Genus AFROPLANORBIS Thielc, 1931 
Type by original designation Planorbis siidanicus Martens 

1885. Mcnetus Westerlund (non H. and A. Adams, 1855), Fauna Palaearc. Reg., V, 
p. 64. No type cited. As subgenus of Planorbis. 

1902. Menetus Westerlund, Rad. Jugoslav. Akad., 151. p. 120. Tvpe Planorbis boissyi 
P. and M. (non Adams, 1855). 

1923. Planorbulina Germain, Rec. Ind. AIus., XXI, p. 179. Citation for Planorbulina 
Jickeli (1874) Fauna der Land und Siisswasser Mollusk Nord-ost-Afrika. 
Dresden, p. 221 ('pour la Planorbis alexandrinus Ehrenberg {Segmentina sous- 
genre Planorbulina)') . 

1925. Planorbula Connolly, Trans. Royal Soc. S. Africa, XII, p. 195 (non Haldeman). 
Anatomy of Planorbis pfeiffcri Krauss. 

1931. Ajroplanorbis Thiele, Handbuch, Teil 2, p. 480. Type Planorbis siidaniciLs von 
Martens. As section of Planorbis. 

1934. Ajroplanorbis Pilsbry, Proc. Phil. Acad. Nat. Sci., 86, p. 55. Type Planorbis 
sudanicus von Martens. 

1936. Ajroplanorbis Ha.\s, Abh. Sencken. Natur. Gesell., No. 431, p. 25. Type Planorbis 
sudanicus von Martens. As genus. 

1939. Planorbulina Haas. Malac. Notes, Field Mus. N. H., Zool., XXIV, p. 100. Cita- 
tion from Jickeli 1874, Nova Acta Acad. Leop. Carol., XXXVII, p. 221. 

1939. Biomphalaria Connolly (part); Ann. South African Mus., XXXIII, part 1, 

p. 483. 

1940. Planorbulina H.\as, Nautilus, p. 33. States that citations from Jickeli's paper 

(1874) are erroneous, there being no reference to this name in the work 
mentioned, the name used being Planorbula. Planorbulina was used by 
tl'Orbigny in 1826 in Foraminifera. 

Shell (plate 81, figs. 2, 3). Small to medium size, orbicular, of few or 
many whorls which may be closely coiled or rapidly increase in diameter; 
usually flattened on both sides; aperture rounded, usually in the same 
plane as the last whorl, lips sharp, the aperture with or without lamellae. 

Animal. Not observed. 

ANATOMICAL CHARACTERISTICS 
PLATE 71 

GENITALIA. Male Organs (fig. 9, Ajroplanorbis pfeifferi (Krauss) ). 
Seminal vesicle occupying about half the length of the ovisperm duct, the 
glandular follicles short and projecting from the side of the duct. Sperm 
duct a narrow tube about as long as the ovisperm duct and seminal vesicle 
combined. Prostate short, composed of five main branches each of which 
branch again two to four times, thirteen diverticula showing at the upper 
or outer end of the prostate. From the figure the diverticula appear to be 
arranged in fan-like manner. There is but one series of diverticula but there 
is no indication of a separate prostate duct. The vas deferens is a long, fine 
duct, apparently as long as the sperm duct and ovisperm duct combined. 

The penial complex has a sac-like preputium with a narrow retractor 
muscle attached to the summit near the junction of preputium and vergic 
sac. The vergic sac is a narrow tube, not much greater in diameter than the 
vas deferens. It is about as long as the preputium and appears from the 
figure to be slightly enlarged at the end. The features of the interior of the 
penial complex are neither figured nor described. 

Female Organs. The spermatheca is an elongated pouch connected with 
the rather long vagina by a duct half as long as the spermatheca. The 



Subfamilies, Genera, and Subgenera — Recent and Fossil 87 

uterus swells behind the vagina to more than twice the diameter of the 
vagina. The nidamental gland is about as long as the uterus and is swollen 
to twice the diameter of the uterus. The oviduct is shorter than the uterus 
and rapidly narrows to meet the sperm duct. The albumen gland is a large, 
elongate-ovate organ, half as high as long. 

Hermaphrodite Organs. Ovotestis apparently a double series of club- 
shaped diverticula. The ovisperm duct is very narrow and its free por- 
tion is about as long as the sperm duct. The seminal vesicle is placed nearer 
the ovotestis than observed in the species of Tropicorbis examined. 

Pilsl)ry's figures of Planorbis adowensis Bourguignat (plate 71, figs. 
10-12) are essentially the same in general generic characters as in pjeifferi 
described above. The prostate (fig. 10) shows about sixteen short divertic- 
ula which are unbranched. The penial complex (fig. 11) shows a wide, sac- 
like preputium and a slender vergic sac equal in length to the preputium. 
The retractor muscle is inserted at the junction of vergic sac and pre- 
putium. Internally (fig. 12) the preputium has three vertical pilasters and 
the verge is very long and slender. The spermatheca (fig. 10) is more 
pyriform than that of pfcifferi and the duct is longer. 

The pseudobranch of Planorbis pfcifferi (fig. 7) appears to be folded as 
it is in Tropicorbis. The figure of the digestive system (fig. 8) shows a wide 
gizzard, a narrow and elongated pyloris, a narrow blind sac, and the intes- 
tine looped about the stomach. The salivary glands form a short loop 
behind the buccal sac. 

The above anatomical notes are drawn from the papers of Connolly 
(1925) andPilsbry (1934). 

Geographical Distribution. Afroplanorbis appears to be distributed 
over northern and central Africa and to include a number of species. 

Species Considered as Valid. The following are the species believed 
to be referable to Afroplanorbis. Other species may be added when their 
anatomy becomes known. 

Afroplanorbis sudanicus (von Martens) Afroplanorbis sudanicus tanganikanus 

Afroplanorbis pfcifferi (Krauss) (Bourg.) 

Afroplanorbis alexandriensis (Ebrenb.) Afroplanorbis bridouxianus (Bourg.) 

Afroplanorbis boissyi (Pot. and Mich.) Afroplanorbis adowensis (Bourg.) 

Afrdjihniorbi.'^ salinariDu (Morelet) Afroplanorbis paetcli (Jickeli) 

Geological Distribution. Not ascertained. The group is probably as old 
as Tropicorbis. 

Remarks. The anatomy of Afroplanorbis sudanicus (von Martens) is 
unknown, but the shell so closely resembles that of Afroplanorbis adowensis 
(Bourg.) that they appear to be congeneric. Pilsbry (1934, p. 54) calls at- 
tention to the similarity of the shells. He also dissected Planorbis adowensis 
(his figures are copied on my plate 71) and found the anatomy to be very 
much like that of Tropicorbis. Connolly (1925, plate 8) figures the genitalia 
of Planorbis pfcifferi Krauss and his figure differs little from that of 
Pilsbry except in specific details. The branched diverticula of the prostate 
are believed to be attributed to faulty drawing rather than to real differ- 
ences in structure. The chief difference between Tropicorbis and Afropla- 
norbis appears to be in the longer seminal vesicle of the latter, the smaller 
number of prostate diverticula, the greater size of the uterus and nida- 
mental gland, and the greater difference in diameter between the preputium 
and vergic sac. 



88 The MoUuscan Family Planorhidae 

The African group would appear properly to take the name Afropla- 
norbis proposed by Thiele, preferably as a genus closely related to 
Tropicorbis. It has no relationship with Planorbula Haldeman which is 
purely an American genus belonging to a different subfamily. The close 
relationship between Tropicorbis of Central and South America and the 
African species here referred to Ajroplanorbis is, as pointed out by Pilsbry 
(1934, p. 55), an interesting parallel in zoogeography. A similar relation- 
ship is found in the Ancylidae and in some groups of land shells. 

In a recent work (1939, p. 483) Connolly uses the generic name 
Biomphalaria Preston for all of the African species once referred to Pla- 
norbula. However, the anatomy of the type of this genus, smithi Preston, 
is unknown and until that species has been examined anatomically it 
would seem unwise to use this name so inclusively. Should the anatomy 
jirove to be like that of the two species here referred to the genus Ajro- 
planorbis, Planorbis adowensis and P. pfeifferi, it would then take prece- 
dence over Ajroplanorbis which would become a synonym of Biomphalaria. 
Tropicorbis appears to be generically distinct from the African species and 
can not be included in either Ajroplanorbis or Biomphalaria, as suggested 
by Connolly (p. 484j. 

Genus SYRIOPLAXORBIS F. C. Baker 

New name for HETF]RODISCUS Westerlund, preoccupied. Type 
Planorbis libanicus Westerlund, originally designated for HETERODISCUS 

1902. Hetcrodiscus Westerluxd, Rad. Jugoslav. Akad., 151, p. 120. Tj'pe Planorbis 
libanicus Westerlund. As subgenus of Planorbis. Non Heterodiscus Sharp, 
Insecta, 1886. 
1905. Heterodiscus Dall, Alaska Moll., p. 83. Type Planorbis libanicus Westerlund, 

As section of Planorbis. 
1931. Heterodiscus Thiele, Handbuch, Teil 2, p. 479. Type Planorbis libanicus Wester- 
lund. As section of Planorbis. 
'Shell n: t. media (d. 14 mm.), supra late profundeque concavo-umbilicata, subtus 
subplana, sub lente distincte sitiraliter lineata. spira magna, utrinquc orbiter subaeciua, 
anfr. 5-6, primi lenti, ultimus subcvlindraceus (typ. PI. libanicus W.).' Westerlund, 
p. 120. 

Original description of Planorbis libanicus Westerlund: 'Testa magnitudine medi- 
ocris, supra late profundeque concavo-umbilicata, infra subplana, nitida, cornea (subtus 
paullo pallidior), firma, laevigata, sub lente forti densissime at distincte spiraliter 
lineata ; anfr. 5^2-6, convexi, interiores utrinque perlente accrescentes, spiram magnum, 
subaequalem formantes, ultimus major, rotundatus, subcylindraceus, supra convexus, 
subtus pone suturam impressam obtusissime angulatus, extrorsum paullo planulatus; 
apertura oblique rotundato-lunaris, marginibus distantibus, disjunctis, basali oblique 
surrecto. Diam. 14, alt. ad apert. 5 mm. 

'Hab. Mons Libanon (legit beat. Evers, Havniensis). 

'Haec species forte typum novi subgeneris format, quod a subgen. Meneto differre 
A'idetur; Testa supra late concavo-umbilicata, infra subplana, sub lente tenue distincte 
spiraliter lineata, spira magna, utrinque subaeque lata.' Westerlund, Nach. Deutsch. 
Malak. GeselL, 1899, pp. 170-171. 

Remarks. All of the information concerning this group name and its 
type species is given above. No specimens for figuring have been obtain- 
able and no figure has been published, as far as known to the writer. 
Westerlund mentions in the description of the species (libanicus) that it 
differs from the subgenus Menetus and that it should become the type of 
a new subgenus, which he later calls Heterodiscus, which is unfortunately 
preoccupied. 



SubjainUies, Genera, and Subgenera — Recent and Fossil 89 

In Westerlund's list of the subgenera of Planorbis (1902, p. 120), the 
type of Menetus is given as Planorbis boissyi P. and M., which is now 
placed in the genus Afroplanorbis, the type of Menetus being Planorbis 
opercidaris Gould. The comparison of Heterodiscus with Menetus would 
indicate that the latter group was somewhat related to the African species 
and the Latin description would fit, in a measure, some species, as adowensis 
and suflanicus. The habitat of Planorbis libanicus is not so far removed 
from the African region as to preclude the possibility that this species 
might group with Afroplanorbis, hence the new name Syrioplanorbis 
(Heterodiscus) would become a synonym of Afroplanorbis. Only an ex- 
amination of the animal of libanicus would positively settle this question. 

Species Considered as Valid. Sijrioplanorbis libanicus (Westerlund) 
is the only species attributable to this genus and, as indicated above, the 
\'alidity of the generic concei:»t is not wholly certain. 

Genus BIOMPHALARIA Preston, 1910 
Type by original designation Biomphalaria S)7iithi Preston 

1901. Plnnorhia J. E. S. Moore, To the Mountains of the Moon, p. 260. Monotype 
Planana albertensis J. E. S. Moore (non Planarin Brown, 1827, or Miiller, 
1776). 

1910. Biomphalarin Preston, Ann. Mag. N. H. (8), VI, p. 535, plate ix, figs. 26, 26a. 
Tyjie Biomphalaria smithi Preston. As genus. 

1927. Planaria Pilsbry and Bequaert, Bull. Amer. Mus. N. H., LIII, p. 121. Monotype 
Planaria albertensis J. E. S. Moore. 

1927. Biomphalaria Pilsbry and Bequ.\ert, op. cit., p. 115. Monotype Biomphalaria 
smithi Preston. As .synonym of Planorbis Miiller. 

1931. Biomphalaria Thiele, Handbuch, Teil 2, p. 479. As section of genus Planorbis. 
Tvpe wrongly given as Planorbis choanomphalus von Martens. 

1934. Biomphalaria Pilsbry, Proc. Phil. Acad. Nat. Sci., 86, p. 55. Type Biomphalaria 
smithi Preston. 

1936. Biomphalaria Ha.a.s, Abh. Secken. Natur. Ge.sell., No. 431, p. 25. Type Biom- 
phalaria smithi Preston. As genus. 

Shell (plate 81, fig. 4). Subdiscoidal, planulate with concave spire, last 
whorl very large; umbilicus open, but shallow; aperture gaping; labrum 
greatly receding below (Preston). The .shell is ultradextral. Of this species 
Pilsbry says (1927, p. 120) 'The prominent character of this species is the 
deviation towards the left of the last half-whorl.' Viewed as a dextral 
species, the last part of the whorl drops below the periphery as in some 
specimens of Gyraidus defiectus. 

Animal. The anatomy of the group is at present unknown. 

Geographical Distribution. Lake Albert Edward, Belgian Congo, 
Africa. Only the type species is known. Planorbis ruppelli Dunker, Pla- 
norbis choanomphalus Martens and Planorbis katangae Haas, included in 
this genus by Haas (1936) appear to belong elsewhere. They do not have 
the characteristics assigned to Biomphalaria. 

Species Considered as Valid. Biomphalaria smithi Preston is the sole 
representative of the genus here recognized. 

Remarks. This genus is unknown anatomically and its true position in 
planorbid nomenclature can not be definitely assigned until the animal has 
been dissected. Pilsbry ( 1927, p. 120) suggests that it is a modification of 
the Planorbis adoiuensis type and might be placed in the same section of 



90 The Molhiscan Family Planorbidae 

the genus Planorbis. In a later publication (1934, p. 55) this relationship 
is again emphasized. In both references by Pilsbry the suggestion is made 
that the shell might have been modified somewhat after the manner of 
Taphius. The shells as figured by Pilsbry (1927, p. 121, reproduced on plate 
81 of this work) are strongly suggestive of Taphius, and Biomphalaria 
might bear the same relationship to Ajroplanorhis that Taphius bears to 
Tropicorbis. Its best place in classification at present appears to be near 
Afroplanorbis as a distinct genus. 

Genus AUSTRALORBIS Pilsbry, 1934 

Type by original designation Planorbis guadaloupensis 
Sowb. = Planorbis glabratus Say 

1883. Menetus Flscher, Man. de Conch., p. 509. Type PI. guadaloupensis Sowb. 
(non H. and A. Adams, 1855). As section of Planorbis 

1899. Menetus Martens, Biol. Cent. Amer., Moll., p. 390 (non H. and A. Adams, 
1855). Martens gives no type but says subgenus is peculiar to South America 
and mentions Planorbis cumingia7ius Dkr., and Planorbis guadaloupensis 
Sowb. as examples 

1905. Planorbina Dall, Alaska Moll., pp. 81, 84. Type by original designation P/a«or£)is 
olivaceus Spix (non Planorbina Haldeman, 1843). As section of Planorbis 

1918. Planorbina Walker, Miscel. Pub. Mus. Zool., Univ. Mich., Xo. 6, pp. 11, 94. 
Type Planorbis olivaceus Spix (non Planorbina Hald, 1843). As section of 
Planorbis 

1921. Planorbina Germain, Rec. Ind. Mus., XXI, pp. 6, 41. Type Planorbis guadalou- 
pensis Sowb. (non Planorbina Haldeman, 1843). As subgenus of Planorbis 

1923. Planorbina Wenz, Fossil. Cat., pars 22, p. 1482. Genotype Planorbis guadalou- 
pensis Sowb. (non Planorbina Haldeman, 1843). As genus and subgenus 

1930. Planorbina H. B. Baker, Oc. Papers, Mus. Zool., Univ. Mich., No. 210, p. 43. 

Type Planorbis olivaceus Spix (non Planorbina Haldeman, 1843). As genus 

1931. Planorbina Thiele, Handbuch, Teil 2, p. 480. Type Planorbis olivaceus Spix 

(non Planorbina Haldeman, 1843). As section of Planorbis 
1934. Australorbis Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 55. Type Plaiiorbis 

guadaloupensis Sowh. (^ Planorbis glabratus Say). As genus 
1938. Australorbis Martins, Contribuicao ao estudo do genero Australorbis Pilsbry, 

1934. On p. 47 lists Brazilian species of this and other genera. Some of the 

species listed belong to Tropicorbis 
1940. Australorbis Scott, Xotulae Naturae, No. 54, p. 9. As genus. 

Shell (plate 77, figs. 29-31, Australorbis glabratus (Say) ). Large, bi- 
concave, smoothish, of slowly widening whorls which are rounded or 
angular laterally (Pilsbry, p. 55). The shell is sinistral. 

Animal. Resembling Tropicorbis in general form. The color is grayish 
or blackish, the mantle mottled with brown or cinnamon. 

ANATOMICAL CHARACTERISTICS 
PLATE 9 {Australorbis glabratus) 

GENITALIA. Male Organs (fig. 10) . The seminal vesicle (SV) is 3 mm. 
long and is an enlargement of the ovisperm duct on which there are many 
elongated follicles placed laterally. For a distance of 2 mm. behind and 4 
mm. in front of the seminal vesicle there are numerous nodes which are 
probably continuations of the seminal vesicle. The sperm duct (SPD) is a 
very long and narrow tube (29 mm. long) of the same caliber throughout. 
The prostate is 8 mm. long and is composed of twenty-three or twenty-four 
diverticula, the two or three anterior diverticula single and unbranched 
and the three posterior diverticula bifurcate. The others, eighteen in num- 



Subjnniilies, Genera, and Subgenera — Recent and Fossil 91 

ber, Inwc three iiiaiii l)ranches from a single stem, each branch again 
dividing two or three times, the secondary diverticula being of unequal 
length. All diverticula arise from the sperm duct in a single series, not in 
nudtiple series, as in Helisoma. A single branched diverticulum is shown in 
fig. 6. The diverticulum enters the sperm duct directly and is not placed 
on a separate duct as in Tropicorbis. The vas deferens (VD) is a narrow 
tube about 10 mm. long, of less diameter than the sperm duct. 

The i)enial comj^jlcx (fig. 10) consists of an elongated, cylindrical, sac- 
like preputium (PR) , about 4 mm. long and 0.7 mm. wide and of about the 
same diameter throughout its length. The very narrow vergic sac (VS) is 
3 mm. long or slightly shorter than the preputium. It is not much greater 
in diameter than the vas deferens. There is a rounded enlargement of the 
vergic sac at the end receiving the vas deferens. There are several sets of 
muscles. A wide retractor muscle (RM) comi^osed of several smaller 
branches, is attached to the ui:)per part of the preputium and to the colu- 
mellar nmscle. On the same side of the preputium there is a wide muscle 
about midway of its length and two smaller muscles near the male open- 
ing which appear to be supporting muscles since they are attached to the 
mantle above the penial complex. On the opposite side of the preputium 
there is a narrow muscle attached to the upper part near the insertion of 
the vergic sac, and a very wide muscle or set of small muscles which are 
attached to the roof of the mantle cavity and are presumed to be support- 
ing muscles (SM). Some of these may aid in retracting the I'jcnial complex 
after coitus. 

Internally (fig. 9) there are two wide, heavy pilasters in the preputium 
tapering to a point at the upper part of the preputial space. The space 
between the pilasters is marked by many cross muscles forming a reticu- 
lated pattern (PL). There is a flattened muscular ring or diaphragm (D). 
The verge (V) is long and very narrow. It tapers to a point and the sperm 
canal is placed at the center (fig. 5). There is no penial papilla. 

Female Organs. The spermatheca is pear-shaped (S) and the duct 
(SD) is narrow and as long as the spermatheca. Both gland and duct 
measure a trifle more than 3 mm. in length. The vagina (VG) is very short 
and wide. The uterus is the same width as the vagina and gradually en- 
larges in diameter to meet the nidamental gland (NG) which is very long 
and wide (about 8 mm. long, 1.5 mm. wide). A part of the uterus projects 
behind the nidamental gland for several millimeters. The oviduct (OD) 
is a narrow tube extending from the ovisperm duct backward. It is about 
twice the diameter of the sperm duct and is about 18 mm. in length. There 
is a rounded carrefour (OF) extending from the oviduct to which the duct 
of the albumen gland is attached. The albumen gland (fig. 8) is rectangular 
in form and is composed of large follicles. The space for the passage of the 
intestine (IX) is quite conspicuous. 

Hermaphrodite Organs. The ovisperm duct (SO) is very long (17 
mm.) and is a simple tube except for the portion occupied by the seminal 
vesicle. The ovotestis is composed of multiple diverticula as seen in situ 
(fig. 10, OT). In cross section (fig. 4) the ovotestis appears to consist of a 
main diverticulum (fig. 1) upon which a number of short divertictila are 
attached (2). The organ is not multiple in the same sense that Helisoma 
is, which is observed to be fan-shaped in section. Several of the diverticula 
contained one large ovum ready for exi)ulsi()n. 



92 The Molluscan Family Planorhidae 

The above description agrees substantially with that of Pilsbry (1934, 
p. 55). The spermathecal duct in the specimens examined was not short, as 
Pilsbry found it, and, therefore, the spermatheca was not really adnate. 
The vergic sac, also, is almost as long as the preputium in the specimens 
examined. With these exceptions the genitalia of glabratus {guadalou- 
pensis) here figured are like the figures of the race christopherensis given by 
Pilsbry on page 57. The figure by Scott (1940, p. 10) agrees with the 
specimens personally dissected, especially in the form of the spermatheca. 

Respiratory and Renal Systems. The pseudobranch is rather long and 
rounded. A frilled crest or ridge extends down the center of the rectum (R) 
which it crosses as a simple ridge to the anal opening (A) and extends 
across the pseudobranch to the lower edge. There is a large pneumo- 
stome (PS). 

The kidney (plate 45, fig. 1) is long and narrow (16 mm. long, 2.5 mm. 
wide). The ureter is nearly 2 mm. long and is a narrow tube directed 
upward at a right angle from the kidney. The veins are very large. The 
pericardium is 3 mm. long and 2 ram. wide. A low, wide ridge extends from 
below the pericardium to the lower end of the kidney. 

Cross sections show several .interesting features. The position of each 
section is shown at A, B, C, D, E, in fig. 1. Section E (fig. 7) through the 
pericardium shows a large lumen nearly filling the entire section, con- 
taining many glandular diverticula. There are no veins. In section D (fig. 
8) the lumen is smaller, rather squarish in shape, with the pulmonary vein 
(AP), large and round, on one side and the renal vein (RA), smaller and 
oviform, on the other side. The low ridge is seen at the left. In section C 
(fig. 9) the lumen is somewhat smaller and there is the same disparity in 
size between the two veins. The ridge (RK), though wide, is higher than 
in section D. In section B (fig. 10) the lumen is much smaller, the veins 
still disproportionate in size and the ridge very wide, but low, and pro- 
jecting over the left margin. In section A (fig. 11) near the base of the 
kidney, the whole organ is seen to be flattened, the lumen very small, the 
veins flattened, more nearly equal, and the ridge wide, flattened, and pro- 
jecting over the left margin. The form of the long ridge to the left of the 
kidney is shown at the left in this section (RD). The ridge is a very 
characteristic feature in the kidney of Australorbis . 

Digestive System. The stomach region (plate 48, figs. 9, 10) resembles 
that of Promenetus, the gizzard rather rounded, not flattened, the pyloris 
long and the blind sac rather short and placed as in Helisoma. The intes- 
tine makes a loop around the stomach and another looji around the liver, 
then runs forward to the rectum which bears a plaited crest or ridge (plate 
48, fig. 9). 

The buccal sac is short and high, not much elongated. The radula sac 
or pouch is large and rounded, somewhat as in Tropicorbis. The salivary 
glands are narrow and nearly three times as long as the buccal sac. They 
are joined behind as in Helisoma. 

Jaws three in number as in Tropicorbis (plate 50, fig. 13). The superior 
jaw is very high, the length being about three times the height. It is finely 
striated on its anterior face. The side jaws are much shorter than the 
width of the superior jaw and are very narrow. The side jaws are shorter 
in comparison with the length of the superior jaw than in most species 



Subjar/illies, Genera, and Subgenera— Recent and Fossil 93 

of Planorbidae. The figure on plate 50 agrees with that by Pilsbry 
(1934, p. 57). 

The raclula formiUa is 31-1-31 to 33-1-33 with 182 rows of teeth (plate 
68, fig. 5) . The center tooth (60) is wider than high, the lower outer corners 
of the base of attachment expanded to the extent that the base is twice as 
wide as the summit of the tooth. There are two sharp, spade-shaped cusps 
which extend below the lower margin of the base of attachment. Lateral 
teeth (1-13) asymmetrical, tricuspid, the cusps sharp, subequal, and 
extending below the base of attachment. The intermediate teeth (14-15) 
differ from the lateral teeth in having either an extra interstitial cusp 
between the ectocone and mesocone (14) or an interstitial cusp as in 14 
and an extra cusp above the ectocone. Marginal teeth ( 16-26) elongated, 
oblique, the mesocone remaining a large sharp cusp, but the entocone 
splitting into three to five small, subequal cusps arranged obliquely. The 
ectocone continues as a large cusp but above it, on the' margin of the tooth, 
there are three to six very small cusps in addition. The ectocone is always 
separated from the mesocone by a distinct gap. The small cusps above the 
ectocone are placed higher up on the tooth than in other genera. The outer 
marginals are very narrow and oblique and the cusps appear as minute 
serrations. Even here, however, the two groups of cusps, mesocone and 
ectocone, are separated by a considerable space. 

Pilsbry (1934, p. 55) figures the radula of the race christopherensis 
which agrees in all essential details with the figures on plate 68. He gives 
the formula as 30-1-30 with seventeen laterals. In specimens personally 
dissected the marginals began on the 16th tooth in two specimens and 
on the 18th tooth in one specimen, the 15th to 17th teeth being intermediate 
in character. These differences are unimportant. 

Scott (1940, pp. 10-12) figures the radula of specimens from Caracas, 
Venezuela, and Puerto Rico, showing great variation in the form of the 
cusps. The Venezuela form with a formula of 45-1-45 may be represen- 
tative of the race oUvaceus. 

The material used for this anatomical study was received from Dr. 
Wm. A. Hoffman and was collected at Lares, Puerto Rico. 

Geographical Distribution. Except for its occurrence in Haiti, Puerto 
Rico, and the Caribbean islands, Avstrcdorbis is a South American group 
(Pilsbry I. It is known in South America from Venezuela southward to 
Argentine Republic. 

Species Considered as Valid. ]\Iany names have been given to varia- 
tions within this genus and consequently there are many synonyms. The 
following species and races appear to be recognizable: 

Australnrbifi ginbratus (Say) (= Quadaloupensis Sowh.) 
Australorbis glabratus christ ophcren.fis Pilsbry 
Australorbis glabratus oUi'accus (Spix and Wagner) 
Australorbis glabratus refulgcns (Diinker) 
Australorbis glabratus higubris (Wagner) 
Australorbis glabratus blauncri (Germain) 
Australorbis antigucnsis (Sowerby) 
A ustralorbis itn 7)i unis ( Liit z ) 
Australorbis bahiensis (Diinker) 
Australorbis tenagophilus (Orbigm-) 

Geological Distribution. This genus probably dates fi'om the Oligocene 
or Miocene period of the "West Indies and South America. 



94 The Molluscan Family Planorhidae 

Remarks. Australorhis is so peculiar in certain of its anatomical char- 
acteristics as to puzzle the systematist regarding its proper position in the 
classification of the family Planorbiclae. In its narrow penial complex with- 
out penial gland it is related to Tropicorbis. The prostate, however, is very 
different from any member of the Planorbinae and superficially resembles 
some of the Helisomatinae in the presence of multiform diverticula. The 
ovotestis is also of a multiform nature. The prostate diverticula are also 
attached directly to the sperm duct instead of to a separate prostate duct 
as is the case in Tropicorbis. In this respect, the prostate of Australorbis 
resembles that of the genus Drepanotrema, the few diverticula in this 
group being attached directly to the sperm duct. The kidney is of the 
Helisoma type, with a distinct ridge. 

In spite of the multiple nature of the diverticula of the prostate and 
ovotestis, the group appears to be related to Tropicorbis and to be correctly 
placed in the subfamily Planorbinae. The absence of a penial gland re- 
moves it from Helisomatinae and Planorbulinae and the absence of a 
flagellum, and also the form of the shell (with overlapping whorls), ex- 
cludes it from the subfamily Segmentininae. When the characteristics of the 
prostate are closely examined it is seen to be uniserial in form in spite 
of the branched nature of the diverticula. Each diverticulum arises from 
the sperm duct as a single tube, the branching taking place after the 
diverticula are above the sperm duct. So also in the ovotestis, each divertic- 
ulum arises from the ovisperm duct as a single tube, the branching being 
on one side only. 

In the Helisomatinae, both the prostate and the ovotestis have the 
diverticula radiating from the ducts like the spokes of a wheel, in fan- 
formation. The ridged kidney is an exception in the Planorbinae. This 
characteristic, as well as the apparent multiple appearance of the prostate 
and ovotestis, may show ancient affinities with the Helisomatinae. Austra- 
lorbis is apparently an aberrent genus of the family. 

Pilsbry has suggested (1934, p. 56) that it might be considered a sub- 
genus of Tropicorbis but this procedure would appear untenable because 
of the peculiar prostate and ovotestis as well as the ridge on the kidney. 
Pilsbry did not examine the ovotestis or the kidney. 

The name Planorbina Haldeman was used for this group by Dall in 
1905, the Brazilian species Planorbis olivaceus Spix and Wagner being 
designated as the type. Germain, in 1921, selected Planorbis guadaloupensis 
Sowb., as type of Planorbina. But as Pilsbry states in his description of 
Australorbis, neither olivaceus nor guadaloupensis answer to Haldeman's 
description 'whorls numerous, nearly equal,' the whorls in these species 
increasing in diameter to such an extent that the last whorl is notably 
wider than the preceding whorl. Haldeman's Planorbina is now considered 
a synonym of Anisus. Pilsbry 's discussion of the reasons for rejecting the 
types proposed for Planorbina, for which no type was designated by 
Haldeman, by Dall or Germain are well stated and do not need to be 
repeated here. 

Genus ANISOPSIS Sandberger. 1875 

Type herein nominated Planorbis calculus Sandberger 

1875. Anisop.sis Sandberger, Land imd Slissw. Conch, der Vorwelt, p. 958. No type 
cited 

1905. Anisopsis Dall, Alaska Moll., p. 81. Plaiwrbis loryi Coq., and Planorbis cal- 
culus Sandb. cited as examples 



Subfamilies, Genera, and Subgenera — Recent and Fossil 95 

Shell (of Anisopsis ccdcidus (Sandberger) , plate 81, fig. 10 ». 'Testa cal- 
culiforinis, superne excavata, inferne latissime uinbilicata. Anfractus 3^/4, 
gracilis, quadrangulates, superne excavati, ad margineuni sui)erum necnon 
ad iimbilicuin carina cincta, suturis tenuibus profundis disjiincti, costulis 
trans versalibus subtilibiis ornati, ultimus permagnus, spiram eminens 
(Sandberger, p. 14). Taf. 1, fig. 7, 7a (stark vergrossert).' 

The shell is ultradextral, with a distinct, sharp carina in the middle of 
the whorls on the right side. The left side also has carinated whorls. The 
whorls are few in number, increasing rather rapidly in diameter. From the 
figures there appears to be a carina at the periphery. 

Horizon and Distribution. Middle or brown Jurassic period. Cajac, in 
layers e and f. Very rare. 

Remarks. The name Anisopsis appears to be a nude name, no type hav- 
ing been formally designated for it, as far as the writer is aware. It also 
appears to have been comparatively unnoticed by recent students of the 
Mollusca. The only American reference observed is that by Dall in 1905, 
who cites Planorbis loryi Coq., and Planorbis calculus Sandb. as examples. 
The original reference is in a stratigraphic table on page 958 of Sandberger's 
work in which Anisopsis appears between Bathyomphalus and Anisus. The 
only valid reason for associating the two species mentioned above with 
Anisopsis is the presence of the stars in the Aliddle ( ]\Iittlerer) Jura and 
the Upper (Oberer) Jura in the table, indicating that these two species 
are the ones intended for this group name, since no others from these 
horizons occur in the body of this work. 

Planorbis calculus Sandberger occurs first on page 14 and should be 
taken as the type of Anisopsis. On page 15 Sandberger mentions the like- 
ness of this sj^ecies to the tricarinate Valvatas of North America typified 
by Valvata tricarinata. The figure of this species does look much like 
Valvata tricarinata on the right side but on the left side the figure is too 
wide, lacking the distinct carina and deep umbilicus of the American 
Valvata. Dall (1905, p. 81) suggests its relationship to Helisoma but the 
left side is different from any species of that genus known. The exact size 
is not given by Sandberger, who states that the figure is much enlarged. 

The second species, Planorbis loryi Coquand (Sandberger, p. 41) is 
more planorboid in form and somewhat different in shape from calculus 
(see plate 81, fig. 11). It is also larger. Sandberger suggests its resemblance 
to Planorbis complanatus (Linn.) (=jontanus Lightfoot) and Planorbis 
carinatus Miiller, but the figures do not resemble either of these species. 
Sandberger's description of this species is as follows: 'Testa calculiformis, 
su])ernc profunde excavata, inferne depressa, latissime umbilicata. An- 
fractus quinque. gracilis, costulis transversalibus tenuibus muniti et carinis 
duabus acutis insignes, prima partem su})eram excavatam, altera basin 
cingente. Apertura trapezoidea, valde iniquilateralis.' 

The horizon and localities for this species are given as follows by 
Sandberger (p. 41) : 'Villers le Lac (physaschicht b), les Rousses, Charix 
bei Nantuar, Alferme und Vigneules am Bieler See in den gleichen Schich- 
ten.' These localities are in the Upper or White Jura. 

The group Anisopsis, which may be designated as a genus of the sub- 
family Planorbinae, may be retained to contain these early fossil species. 
The two species referred to this genus may not be congeneric, loryi appear- 



96 The MoUuscan Family Planorhidae 

ing more like some of the species of Planorbis or Anisus. IVIany of the 
names of groups of the Planorbidae have been used rather loosely by 
European writers. Sandberger, for example, lists the subgenera Menetus, 
Helisoma, and Carinifex among the European fossils, groups which we now 
know are confined to America and have no representatives outside the 
Western Hemisphere. All of the extinct Planorbidae, both American and 
European, are badly in need of a thorough taxonomic revision. 

Species Considered as Valid. Anisopsis calculus (Sandberger). the 
genotype, is the only sj^ccies unciucstionably assigned here. The assignment 
of Planorbis loryi Cociuand seems indefensible. 

Subfamily SEGMEXTININAE F. C. Baker, New 

The prostate diverticula are simple sacs placed in a single row along a 
prostate duct as in the subfamily Planorbinae. The penial complex has 
one or two flagella placed at the end of the vergic sac and in addition sev- 
eral genera have a penial gland in the preputium. The jaw is fragmented 
as in Planorbinae. The radula teeth are modified by additional cusps or 
by the presence of many interstitial cusps. The kidney is without a ridge. 

Type genus Segmentina Fleming. 

The groups included in this subfamily are as follows: 

With penial gland but without duct: Segmentina, Hippeutis, Pingiella. 
With penial gland and an external duct: Intha. 
Without penial gland: Polypylis, Drepnnotrema, Acrorbis. 
With long flagella: Pingiella, Polypylis, Intha. 
With short flagella: Scgme7itina, Hippeutis, Acrorbis. 
With both long and short flagella: Drepanotrema. 

With lamellae or barriers within the aperture: Segmentina, Polypylis, Trochorbis. 
Without lamellae or barriers within the aperture: Hippeutis, Helicorbis, Pingia, 
Intha, Drepanotrema, Platytajyhiu.-^. Acrorbis. 

Several groups have not been examined anatomically and their position 
is doubtful. Such are Helicorbis, Trochorbis, and Platijtophius. The fossil 
group Paraplatiorbis must, of course, be placed by shell characters alone. 

Genus SEGMENTINA Fleming, 1817 
Monotype Xautilus lacustris Lightioot ^^ Planorbis nitidus O. F. Miiller 

1817. Segmentina Fleming, Edinburgh Encyclopedia. Conchology, ed. VII, Vol. XII. 

Monotype, Nautilus lacustris Lightfoot = Planorbis nitidus O. F. Miiller 

1818. Segmentina Fleming, Supplement to 4-6th ed. Encyc. Brit., Ill, 'Conchology,' 

p. 309. Type Nautilus lacustris Lightfoot 

1819. Hemithalamus Le.ach, Moll. Brit. Synop. (proofs), p. 137 

1831. Hemithalamus 'Leach' Turton, Man. Land Fresh-water Shells Brit. Isl., p. 116. 
In synonymy of Segmeyitina nitida 0. F. Miiller 

1833. Hemithalamus Fitzinger, Syst. Verz, p. 110 

1840. Segmentaria Sw.\inson, Treat. Malac, p. 337. Lapsus for Segmentina. As sub- 
genus of Planorbis 

1842. Segmentina H.'\ldem.\n, Mon. Fresh-water Univ. Moll., U. S., p. 14. No type 
cited. As subgenus of Planorbis 

1847. Segmentina Gr.ay. Proc. Zool. Soc, p. 509. Type Nautilus lacustris Lightfoot. 
As genus 

1847. Discus Gray, Proc. Zool. Soc, p. 509. No type cited. As synonym of Seg- 
7)ienti7ia 

1850. Segmentina (part) Stein, Schnecken u. Musch. Berlins, p. 78. Segmentina x 
Hippeutis 



A 



Subfamilies, Genera, and Subgenera — Recent and Fossil 97 

1855. SegmcHti)ia Moquin-Tandon, Hist. Moll. Terr. Fluv. France, II, pp. 423, 424. 

Typo Planorbis nitidus Miiller. As genus 
1865. Scgmentina Binney, L. and F-W. Shells N. A., II, p. 136. No type cited. As 

genus 
1867. Appendicular id (])art) Ficinus, Zeits. fiir gesamm. Naturw., XXX, p. 363 
1870. Segmcntina D.'VLL, Ann. N. Y. Lye. N. H., IX, p. 352. Type Planorbis lacustris 

Lightfoot. As genus 

1883. Segmenlina Fi.scher, Man. de Conch., p. 509. T.ype Planorbis nitidus Mi'ill. As 

subgenus of Planorbis 

1884. Segmentina Tryon, S. and S. Conch., Ill, p. 107. Type Segmentina lacustris 

Lightfoot. As genus 

1885. Segmentina We.steklund, Fauna Pal. Reg., V, p. 85. Xo type cited. As sub- 

genus of Planorbis 

1886. Segmentina Glessin, Syst. Conch. Cab., ed. 2, XVII, p. 34. Tj'pe Planorbis 

nitidus Miiller. As genus 
1902. Segmentina Westerlund, Rad. Jugoslav. Akad., 151, p. 121. Type Planorbis 

nitidus Miiller. As subgenus of Planorbis 
1905. Segmentina Dall, Alaska Moll., p. 97. Type Planorbis nitidus Miiller. As genus 
1912. Segmentina Hannibal, Proc. Mai. Soc. Lond., X, p. 154. Type Planorbis nitidus 

Miilleir. As subgenus of Planorbis 
1915. Segmentina Preston, Fauna Brit. India, Moll. FW. Cast, and Pelec, p. 124. 

Type Phnwrbis nitidus Miiller. Includes species now referred to Helicorbis, 

Trochorbis, and Polypylis 

1917. Segmentina L. Soos, Ann. Hist. Nat. Musei Hungarici, XV, pp. 140, 142. Type 

Planorbis nitida Miiller. As genus 

1918. Segmentina Walker, Miscel. Pub., Mus. Zool., Univ. Mich., Xo. 6, p. 13. Type 

Nautilus lacustris Lightfoot. As genus 

1919. Segmentina Annand.ale and Prash.\d, Rec. Ind. Mus., XVIII, p. 56. Type 

Planorbis nitidus Miiller. As genus 
1921. Segmentina Germain, Rec. Ind. Mus., XXI, p. 163. T.ype Planorbis nitidus 

Miiller. As genus 
1923. Segmentina Wenz, Fossil. Cat., pars 22, p. 1661. Genotype Segmentina lacustris 

(Mantagu). As genus 
1926. Segmentina Lindholm, Archiv. fiir Mollusk., 58 year. Heft 6, p. 252. Monogeno- 

type Nautilus lacustris Lightfoot {^Planorbis iiitidus Miiller). As genus 

1926. Segmentina Kennard and Woodward, Syst. Brit. Non-Marine Moll., p. 89. Tj^pe 

Planorbis nitidus Miiller. As genus 

1927. Segmentina Pilsbry and Beqluert, Bull. Amer. Mus. N. H., LIII, p. 128. Type 

Planorbis nitidus Miiller. As genus 

1929. Segmentina H.aas, Trab. Museo Cien. Nat. Barcelona, XIII, p. 388. Type evi- 
dently Planorbis nitidus Miiller. As genus 

1931. Segmentir^a Germain, Moll. Terr. Fluv. France, II, p. 542. Type Segmentina 
nitida (Miiller). As genus 

1931. Segmentina Thiele, Handbuch, Teil 2, \). 481. Type Anisus (S.) nitidus (Miiller). 
As subgenus of Ajiisus 

1935. Segmentina A. Soos, Allat. Kozlem., XXXII, p. 29. As genus 

Shell (plate 79, figs. 1-3). Small, ultradextral, smooth, and glossy; 
whorls few, notably overlapping the body whorl embracing most of the 
preceding whorls, causing the preceding whorl to project far within the 
width of the aperture; periphery rounded or carinated. Cavity of the last 
whorl restricted by several barriers, each set usually composed of three 
large transverse lamellae, parietal, basal, and palatal. There may be other 
smaller lamellae (plate 76, fig. 4). The internal lamellae are composed of 
enamel-like substance. The embryonic whorls have spiral rows of small pits. 



98 The MoUuscan Family Planorbidae 

Animal. With a short foot, rounded in front, jiointed behind; tentacles 
fihform, enlarged at the base, the eyes sessile at their inner bases. Edge of 
mantle thickened. The color of the animal is brownish black much paler 
when immature. 

ANATOMICAL CHARACTERISTICS 
PLATES 2 and 3 

GENITALIA. Male Organs (plate 3, fig. 2) . Seminal vesicle sac-like, 
about three times the diameter of the ovisperm duct with several pro- 
tuberances near the posterior end. It is about 2 mm. long. Sperm duct long 
(4.5 mm.) and of small diameter. Prostate moderately long (1.7 mm.) 
with twenty -two to twenty-five club-shaped diverticula of varying lengths, 
placed on a separate prostate duct, which joins the sperm duct to form the 
vas deferens. The free portion of the prostate duct is about 0.7 mm. long 
and of larger diameter than the sperm duct. In the specimens examined the 
posterior end of the prostate duct is free of diverticula for about 0.3 nnn. 
The vas deferens is of medium length (about 3 mm.) and of small diameter. 
A cross section through the prostate and sperm duct shows the relative 
position of these parts of the animal (plate 3, fig. 3). 

The penial complex (plate 3, fig. 1) is very long (about 3 mm.). The 
preputium (PR) occupies half of the length of the complex and is elongate- 
pyriform in shape, the upper part swollen. The vergic sac (VS) is very 
long and narrow, almost tube-like, and is as long as the preputium. There 
are two short, narrow flagella (FL) at the end of the vergic sac at the 
point of insertion of the vas deferens. There is a single, rather wide 
retractor muscle, but no supporting muscles. 

Internally (plate 2, fig. 2) the preputium presents some striking fea- 
tures. There is a single heavy ridge on one side (plate 2, fig. 1) which 
extends vertically up a large portion of the preputium and is in the nature 
of a pilaster (PL). This ridge merges into a long, sac-like glandular organ 
which is reflected toward the base or opening of the preputium (SB). 
This penial gland has a shallow cup, the bottom of which is paved with 
small protuberances resembling pavement (plate 2, fig. 3), the fleshy sides 
rolled upward. In cross section this gland presents the appearance shown in 
fig. 4 of plate 2. On the right side of the preputium there is a long, very 
narrow pilaster which extends the whole length of the preputium from 
the external opening upward to the muscular ring (D) separating the 
preputium from the vergic sac. The large gland is free from attachment to 
the wall of the preputium and is connected only with the large left 
pilaster. 

The verge (V) is long and very narrow. At its distal end it bears a 
fleshy papilla (plate 2, figs. 5, 6, PA) which is also long and narrow. This 
papilla is an extension of the verge only from one side, the sperm canal 
(SC) being in the center of the verge at the end, as shown in the figures. 

Female Organs. The spermatheca (plate 3, fig. 2) is long and sac-like 
and is attached to the vagina by a long narrow duct which is somewhat 
longer than the spermatheca. The spermatheca is constricted about midway 
of its length. The vagina is narrow and about 0.5 mm. in length. The 
uterus is about twice the diameter of the vagina and is a trifle over 1 mm. 
in length. The nidamental gland is very long (about 3 mm.), sac-like, and 
envelops the uterus. The oviduct is about half the diameter of the 



SubjaniiUes, Genera, and Subgenera — Recent and Fossil 99 

nidamcntal gland and about 1.5 mm. long. The albumen gland is rather 
small and oval in shape. 

Hermaphrodite Organs. The ovotestis (plate 3, fig. 2) consists of rela- 
tively few (less than twenty) large club-shaped diverticula. They are 
placed in a double row on the ovisperm duct. The ovisperm duct between 
seminal vesicle and ovotestis is very short, but anteriorly, betw^een the 
seminal vesicle and the oviduct, it is a long (2 mm.), narrow tube. 

The figures on plates 2 and 3 agree in the main with those already 
published by European malacologists. L. Soos's figure (1917, p. 44, fig. 17) 
is the same, showing the few large ovotestis diverticula, the elongated 
spermatheca and duct, and the few diverticula on the prostate. The flagella 
are shown somewhat longer than those in the figure on plate 3. Germain's 
figure (1931, p. 543, fig. 56) is practically the same, the flagella being 
more like the figure on plate 3. 

Respiratory and Renal Systems, The pseudobranch (plate 3, fig. 4) is 
rather small, smooth, elongate-ovate, and folded. The pneumostome is 
very large (fig. 4, PS). 

The kidney (plate 47, fig. 22) is very long (8 mm.) and narrow, ribbon- 
like, the short ureter reflected at right angles to the kidney. In cross sec- 
tion (fig. 23, below the middle) it is seen to be rounded, a trifle wider than 
high, with the veins placed at the upper corners of the lumen, which is 
oval in sha]K'. There is no superposed ridge. 

Digestive System. The stomach region (plate 48, fig. 16) is very nar- 
row, divided into crop, gizzard, and pyloris. There is a short blind sac. 
The intestine makes a sharp turn about the stomach and another around 
the liver, then runs forward to the rectum. 

The buccal sac is much elongated, the salivary glands short, wide, and 
looped behind. There is a conspicuous radula sac which projects notably 
from the rear end of the buccal sac. 

The jaw (plate 50, fig. 24) is horseshoe-shaped, and composed of many 
small plates (about sixtv). It is similar in form to that of Planorbis. 

Radula (plate 69, fig. 7). The formula is 23-1-23 with 164 rows of 
teeth. The central tooth is wdder at the lower edge of the base of attach- 
ment than at the upper margin of the tooth. The two short cusps do not 
reach the lower margin of the base of attachment. Lateral teeth (1-7) 
long and narrow, the reflection low and wide and placed high up on the 
tooth. There are seven cusps, dagger-like and subecjual in size, the ecto- 
conic cusps a trifle smaller. There are six teeth which may be called inter- 
mediate (8-13), since the cusps are a trifle smaller than those of the lateral 
teeth. ^larginal teeth (14-21) with the reflection very low and wide, 7- 
cuspid, the mesocone a trifle larger than the three cusps on each side. The 
outer marginals (22, 23) are vestigial. The teeth are all crow^led on the 
membrane, some of them even overlapping. The teeth are very uniform in 
size and shape. 

Twelve specimens of Segmentina nitida were dissected, collected from 
marshes in a meadow in Czerniakow, a suburb of Warsaw, Poland, by 
A. Jankowski. 

Geographical Distribution. Typical Segmentina is distributed through- 
out Europe and northern Asia. A single species, 5. nitida (Miiller), is recog- 
nized, with several races, by Westerlund and others. Some small species, as 



100 The Molluscan Family Planorhidae 

kempi Preston and angusta Jickeli, may be true Segmentina. Species 
quoted from northern Africa probably belong to other genera, as Ajropla- 
norbis. South African species may belong to an undescribed group. The 
Indian and Chinese species included by authors in Segmentina probably 
all belong to Poli/pylis, Pingiella, or Helicorbis. Only an anatomical ex- 
amination can correctly place the many species referred to segmentina. 

Geological Distribution. Oligocene period to Recent fauna. 

Species Considered as Valid. Since the genus Segmentina is not found 
in America, it is extralimital to the scope of the present work. Segmentina 
7}iti(Ja (Miillerl, the genotype, is the only species definitely considered. 

Remarks, The genus Segmentina is distinguished not only by its glossy 
shell with the embracing body whorl and internal barriers, but also by its 
genitalia with the two short flagella on the verge, the few large ovotestis 
diverticula, the ductless penial gland in the preputium, and the papilla at 
the end of the verge. No mention is made of this peculiar gland in any 
w^ork consulted. The prostate is on a separate duct as in the Planorbinae. 
These special features of the anatomy distinguish Segmentina from all 
other genera of Planorbidae. 

The generic name has been used in a rather wide sense and has included 
one group which belongs in another subfamily {Planorbula) and several 
other related groups which are separated generically from Segmentina 
{Popypylis, Pingiella, Helicorbis) . As typified by Planorbis nitidus Miiller 
it is a well characterized genus. 

Segmentina nitida appears to be a favorite host for parasitic worms, 
all of the twelve specimens examined being more or less heavily infested. 
The ovotestis appeared to be most affected and in several specimens this 
organ was almost obliterated. The liver was also affected. 

Genus HIPPEUTIS (Agassiz AISl Charpentier, 1837 

Type designated by Clessin in 1886, Pknwrbis complanatus Drap. {= Helix 
jontana Lightfoot), one of the two species originally included 

1837. Hippeutis 'Aga.ssiz' in J. de Ch.^rpentier. Neue Denksch. Allg. Schweiz. Naturw., 
I, No. 2, p. 22. As subgenus of Planorbis 

1837. Hippeutis Gr.\y, in Turton, Man. Land FW. Shells Brit. IsL, Ed. 2, p. 243. As 
subgenus of Planorbis 

1844. Hippeutis Hartm.\nn, Erd-und Siisswussser-Gast. der Schweiz., V, pp. 51, 87. 
As subgenus of Planorbis 

1850. Hippcutes M. E. Gr.\y, Fig. Moll. Anim., IV, S^vst. Arrang., p. 119. Typographi- 
cal error for Hippeutis 

1850. Segmentina (part) Stein, Leben. Schneck. Muschl. Berlins, p. 78. Xon Seg- 
mentina Fleming, 1817. (Segmentina plus Hippeutis) 

1855. Hippeutis Moquin-T.4Ndon, Hist. Moll., Terr. Fluv. France, II, pp. 423, 426. 
Type Planorbis jontanus (Lightfoot). As genus 

1885. Hippeutis Westerlund, Fauna Palearc. Reg. Binnen. Conch., V, pp. 65, 84. No 

type cited. As subgenus of Planorbis 

1886. Hippeutis Clessin, Syst. Conch. Cab., Ed. 2, XVII, p. 34. Type Planorbis com- 

planatus Drap. As subgenus of Planorbis 

1902. Hippeutis Westerlund, Rad. Jugoslav. Akad., 151, p. 121. Type Planorbis 
jontanus (Lightfoot). As subgenus of Planorbis 

1905. Hippeutis D.\ll, Alaska Moll., pp. 82, 86. Type Planorbis fontanus (Lightfoot). 
As subgenus of Pla^wrbis 

1912. Hippeutis H.-vnnib.al, Proc. Mai. Soc. London, X, p. 154. Type Planorbis com- 
planatus Drap. (= Helix jontana Lightfoot). As subgenus of Planorbis 



I 



Subfamilies, Genera, and Subgenera — Recent and Fossil 101 

1915. Hippcutiii Prestox, Fauna Brit. India, Moll., FW. Gast and Pelec, p. 124. Type 
Planorbis jontanus (Lightfoot). As section of Phuiorbia 

1918. Hippeutis Walker, Mis. Pub. Zool. Mus., Univ. Mich., No. 6, p. 94. Type Pla- 
norbis jontanus (Lightfoot). As subgenus of Planorbis 

1923. Hippeutis Wexz, Fossil. Cat., Pars 22, p. 1633. Genotype Hippeutis compla- 
natus (Drap.) = Helix jontana Lightfoot. As genus 

1923. Hippeutis Germ.ain, Rec. Ind. Mus., XXI, pp. 8, 159. Type Planorbis jontanus 
(Lightfoot). As subgenus of Planorbis 

1926. Hippeutis Lixdholm, Archiv. fiir Mollusk., 58 year, Heft 6, p. 253. Ideogeno- 
type Planorbis complanatus Drap. As genus 

1926. Hippeutis Kenxard and Woodward, Syn. Brit. Non-Marine Moll., p. 69. Type 

Helix complanatus Linn. As subgenus of Planorbis 

1927. Hippeutis Pilsbry and Bequaert, Bull. Amer. Mus. N. H., LIII, p. 128. Type 

Planorbis complanatus Drap. = P/«nor6zs jontanus (Lightfoot). As subgenus 

of Planorbis 
1929. Hippeutis ^as, Trab. Museo Cien. Nat. Barcelona, XIII, p. 387. Type evidently 

Helix jontana Lightfoot. As genus 
1931. Hippeutis Germaix, Moll. Terr. Fluv. France, II, p. 541. Type not cited but 

Planorbis complanatus (Linn.) described. As subgenus of Planorbis 
1931. Hippeutis Thiele, Handbuch, Teil 2, p. 481. Type Anisus (H.) complanatus 

(Linn.). As subgenus under genus Anisus 
1935. Hippeutis A. Soos, Allat. Kozlem., XXXII, p. 29. As subgenus of Segmentina. 

No tj-pe cited 

Shell (plate 79, figs. 4-6). Small, ultradextral, lens-shaped, shining, the 
body whorl very wide and overlapping most of the inner whorls and form- 
ing a sharp keel at the periphery, the preceding whorl forming a sharp 
extended ridge on the parietal side of the aperture. Aperture triangular, 
outer lip thin. There are no barriers or lamellae within the aperture. The 
embryonic whorls have spiral punctures as in Segmentina. 

Animal. Not differing from that of Segmentina in general form. The 
body of the animal is clear and translucent. 

ANATOMICAL CHARACTERISTICS 
PLATE 2 {Hippeutis complanatus (Linn.) ) 

GENITALIA. Male Organs (fig. 15) . Seminal vesicle rather short 
(about 0.7 nun.), placed midway between ovotestis and oviduct, the di- 
ameter of the organ about the same as the ovosperm duct, with many 
pustule-like vesicles. Prostate short (about 0.6 mm.) with ten long and 
narrow diverticula. Free portion of prostate duct short (fig. 8). Sperm duct 
iSPD) long (over 1 mm.) and of large diameter. Vas deferens (VD) about 
as long as sperm duct, but of smaller diameter. 

Penial complex (plate 2, fig. 14) less than 1 mm. long. Preputium (PR) 
strikingly pyriform, tapering to a narrow neck near the outlet. Vergic sac 
(VS) shorter than the preputium, sac-like, of much smaller diameter than 
the preputium. There are two short flagella (FL). There is a single wide 
retractor muscle (RM) attached to the preputium at the lower part of the 
bulbous swelling. 

Internally (fig. 12), the preputium has two large fleshy pilasters (PL), 
to the left one of which is attached a large, sac-like penial gland, which 
extends crosswise of the preputial cavity (SB). There is a depression at the 
end of the gland but apparently no cavity or cup. The square end of the 
gland is folded backward upon itself. It is shown folded in fig. 12 (SB) and 
with the end stretched out in fig. 9, where the small depression may be 



102 The Molluscau Family Planorhidae 

plainly seen. The retractor muscle (RM) is attached to the preputium at 
the point where the gland joins the pilaster (fig. 12, SB). 

The verge is swollen above and tapers to a narrow diameter for about 
half its length (V). The sperm canal has a central outlet but there is no 
papilla. There is a narrow muscular ring or diaphragm (D) between vergic 
sac and preputium. The two short flagella (FL) are hollow and under high 
power show a minutely punctate surface at the upper rounded end (fig. 11). 

Female Organs (fig. 15) . The spermatheca (S) is long, ovate, sac-like 
and is joined to the short, wide vagina (V) by a long, tube-like duct, which 
is twice the length of the spermatheca. The uterus (U) is twice as wide 
as the vagina, and shorter than the spermatheca and its duct. The nidamen- 
tal gland (NG) is longer than the uterus, much swollen and about half 
as wide as long. The oviduct (OD) is short (about 0.5 mm.) and about 
the same diameter as the uterus. There is a large, bulbous carrefour (CF) 
which receives the duct from the long and narrow albumen gland (AL; 
also fig. 10). 

Hermaphrodite Organs. The ovotestis (OT) has about thirty club- 
shaped diverticula jilaced for the most part in a double row (fig. 7). The 
ovisperm duct (SO) is very long (about 2 mm.) and of small diameter. 

Odhner (1929, p. 32, fig. 13) figures the genitalia of this species agree- 
ing in most resi)ects with the material personally examined. A few points, 
however, are figured differently from the position observed in the speci- 
mens studied. The prostate is shown as having thirteen diverticula 
rather widely spaced on the sperm duct, cjuite different from the long, 
crowded diverticula personally observed (see plate 2, fig. 15, PES). The 
ovotestis diverticula are shown extending in pairs from a short duct which 
enters the ovisperm duct. In this species, as well as others of this subfamily 
and of Planorbinae, the ovotestis diverticula arise in pairs directly from 
the ovisperm duct, each diverticulum entering the duct separately (see 
plate 2, fig. 7). No mention is made of a separate prostate duct or of a 
gland in the preputium. An elongated object in the upper part of the 
prej^utium is shown in Odhner 's figure which might represent this organ. 

Odhner's figure of the radula of Hippeutis complanatus differs some- 
what from the radula as personally examined, there being no interstitial 
cusps between the larger cusps. The formulas of Odhner's specimens agree 
exactly with ours. 

Respiratory and Renal Systems. The pseudobranch (plate 2, fig. 13) 
is small, rather narrow, and })ierced above by the rectum (P). The pneu- 
mostome is very large. 

The kidney (plate 46, fig. 17) is rather short (1.5 mm.) and wide, the 
greatest width being almost one third of the length. The ureter is not 
sharply reflexed as in Segmentina, but extends horizontally into the mantle 
cavity. A cross section below the middle (fig. 18) shows the kidney to be 
flattened, the lumen rounded with the veins placed at the upper corners 
of the lumen. There is no superposed ridge. The kidney of Hippeutis is 
quite different from that of Segmentina (compare fig. 17, plate 46, with 
fig. 22, plate 47). 

Digestive System. The stomach (plate 48, fig. 12) is elongated, as in 
Segmentina. The intestine loops around the stomach and liver, and there 



Subfmnilies, Genera, and Subgenera — Recent and Fossil 103 

is a larj^e blind sac. The buccal sac is elongated, narrowed in front with a 
large radiila sac behind. The salivary glands are short and do not extend 
far beyond the posterior end of the buccal sac. They are joined behind as 
in Scgmcntina. 

The jaw is fragmented as in Segmentina and is made up of many 
small plates. 

The radula formula is 16-1-16, with 150 rows of teeth. The center tooth 
is higher than wide with two wide cusjis which do not reach the lower 
margin of the base of attachment. The laterals (1-9) are squarish and 
tricuspid, the mesocone large and almost reaching the lower margin of 
the base of attachment. The entocone is shorter than the mesocone. The 
cctocone is shorter than the entocone and is placed high on the margin of 
the tooth. In the marginal teeth the reflection is wide and low and is placed 
high u\) on the tooth. The entocone and mesocone are of equal length and 
the ectocone is shorter with two small cusps above on "the outer margin of 
the tooth. The radula teeth of Hippeutis resemble those of Bathyomphahis 
contortus shown on plate 68, fig. 1. They are not like those of Scgmcntina 
nitida figured on plate 69, fig. 7. 

The above anatomical information was obtained from specimens col- 
lected in a pool on a meadow in Jabtonna, 16 km. north of Warsaw, 
Poland. The specimens were obtained by Mr. A. Jankowski. 

Geographical Distribution. Europe from Great Britain, Norway, and 
Sweden south to Portugal. Italy, and Albania. Eastward to northern 
Siberia. A palearctic group. It has been recorded from northern Africa and 
the group may be circum-]\Iediterranean in distribution. As in Segmentina 
a number of species have been described with many varieties. The species 
cited from South x\frica, India, and China probably belong in other genera. 

Species Considered as Valid. The following species are apparently 
referable to Hippeutis: 

Hippeutis complanatus (Linn.) Hippeutis raymondi (Bgt.) 

Hippeutis riparius (Westerlund) Hippeutis junodi (Connolly) 

Hippeutis syraciisanus (Cafici) Hippeutis benguelensis (Dunker) 

Hippeutis diaphaneUus (Bgt.) 

Geological Distribution. From the Lower Eocene period (Wenz). 
Eighteen species and races of fossil Planorbis are referred to this genus 
by Wenz. 

Remarks. Hippeutis complanatus resembles Segmentina nitida in its 
anatomy. The prostate, however, has fewer diverticula. The penial gland 
differs in shape but both are attached to the right pilaster. The whole 
genitalia of Segmentina are much elongated while these organs in Hippeutis 
are short and heavy. Internally the penial complex of the two groups 
differs in details. The kidneys of the two genera are quite unlike. The 
radula resembles Bathyomphahis rather than Segmentina. The shell is 
wholly without barriers or lamellae of any kind within the aperture and 
this characteristic at once marks Hippeutis as a separate genus. 

Species from northern Africa and eastern Asia have been assigned to 
Hippeutis but until these species have been examined anatomically this 
reference remains open to doubt. The Asiatic forms probably belong to 
Benson's genus Helicorbis. Parasites were not observed in any of the 
material examined. 



104 The Molluscan Family Planorhidae 

Genus POLYPYLIS Pilsbry, 1906 

Type by original designation Segmentina largillierii 
(Dunker)(= S. hemisphaerula (Benson) ) 

1906. Polijpylis Pilsbry, Proc. Acad. Nat. Sci. Phil., LVIII, p. 166. Type Segmentina 
largillierti (Dunker). As subgenus of Segmentina 

1921. Segmentina (part) Prashad (non Fleming), Rec. Ind. Mus., XXII, p. 585. 

Mentions Segmentina calathus (Benson), included in Polypylis 

1922. Segmentina Annandale (non Fleming), Rec. Ind. Mus., XXIV, p. 362. 

Mentions Planorbis calathus Benson and Planorhis caenosus Benson, both 
included in Polypylis 

1923. Polypylis Germain, Rec. Ind. Mus. XXI, p. 164. As synonym of Segmentina 
1939. Polypylis Haas, Field Mus. N. H., Zool., Miscel. Notes, XXIV, p. 96, fig. 8a. 

Type Segmentina largillierti (Dunker) (= <S. hemisphaerula (Benson)). As 
subgenus of Segmentina 

Shell (plate 79, figs. 7-9) less compressed than Segmentina (nitida) and 
not carinate, but glossy with deeply clasping whorls. The parietal lamina 
is obliquely transverse, the others transverse, basal long, a shorter one in 
the outer wall, and one or two in the upper margin. There are several or 
many barriers (Pilsbry). The embryonic whorls are punctured. 

Animal. Not examined. 

ANATOMICAL CHARACTERISTICS 
PLATE 5 

GENITALIA. Male Organs (fig. 7) . Seminal vesicle (SV) almost twice 
the diameter of the ovisperm duct, rather long (2 mm.) convoluted, with 
but few pustulose excrescences. The vesicle gradually decreases in diam- 
eter to the ovisperm duct which is not sharply distinguished from the 
vesicle. Sperm cluct (SPD) about 3 mm. long, rather narrow. Prostate 
1.3 mm. long, on a separate prostate duet (PD), consisting of twenty-eight 
to thirty-four long and narrow diverticula, the tip of which is bent over 
in most of the diverticula (fig. 4). Several of the diverticula are bifid at 
the end. The free prostate duct is very short. The vas deferens (VD) is a 
small, tube-like duct somewhat shorter than the sperm duct. 

The penial complex (plate 8, fig. 10) is long and narrow (0.5 mm. long). 
The preputium (PR) is sac-like, rather narrow and elongated (1 mm. 
long). The vergic sac (VS) is two-thirds as long as the preputium and is 
very narrow. There is a single flagellum (FL) which is long (over 1 mm.) 
and narrow and has a bulbous enlargement at the end which is almost half 
as long as the flagellum. The narrow part of the flagellum has about the 
same diameter as the vergic sac. The vas deferens enters the vergic sac 
at one side of the flagellum, as shown in the small figure in fig. 10. There 
is one large retractor muscle (RM) which is attached to the preputium 
near the junction of this organ with the vergic sac. 

In Polypylis calathus there are two short flagella and the vergic sac is 
longer than in hemisphaerula. The pilasters, also, are very thick pads in 
calathus. There are over thirty diverticula on the prostate of calathus and 
the seminal vesicle is very large with projecting vesicles. 

Internally, in the penial complex of hemisphaerula (plate 8, fig. 9) the 
preputium has two pilasters extending the whole length of the sac. There 
is a small, narrow muscular ring or diaphragm (D) separating the preputial 



Subjamilies, Genera, and Subgenera — Recent and Fossil 105 

cavity from the vcrgic cavity. The verge (.^^) is long (0.7 mm.) and very 
narrow, tube-like and at the end there is a fleshy papilla and the sperm 
canal has its outlet at the side of the verge just above this papilla (plate 
5, fig. 6) . There is no penial gland in the penial complex. 

Female Organs (plate 5, fig. 7). The spermatheca (S) is rather small 
and is attached to the long and narrow vagina by a narrow duct (SD) 
about 1 mm. long. The vagina rapidly enlarges from its external opening 
to the point of juncture of the spermathecal duct (VG). The uterus (U) 
is not much longer than the vagina. The nidamental gland is long (2 mm.) 
and much swollen (XG). The oviduct (OD) is short (1 mm. long) and of 
about the same diameter as the uterus. There is a large carrefour (CF). 
The albumen gland is large (1.7 mm. long) and ovate in outline (fig. 2). 

Hermaphrodite Organs. The ovotestis (fig. 7, OT) consists of many 
very long and club-shaped diverticula placed in a double series. As many 
as thirty-eight pairs of diverticula were counted in one specimen. The 
ovisperm duct (SO) is very short between the ovotestis and seminal 
vesicle and very long (2.5 mm.) between the seminal vesicle and the 
oviduct. 

Respiratory and Renal Systems. The pseudobranch (plate 5, fig. 3) is 
long and narrow and soniewliat folded, squarely truncated at the lower 
margin. There is a large pneumostome. 

The kidney of Polypylis hemisphaerula is very long (7 mm.) and 
narrow. It resembles the kidney of Polypylis calathus (plate 47, fig. 24) 
which is long and narrow and 9 mm. in length. A cross section is similar 
to that of calathus (plate 47, fig. 25) which shows the kidney to be flat- 
tened, without a ridge, the lumen oval, wider than high with the two 
lateral veins of large diameter. In hemisphaerula the lumen is rounder and 
the veins relatively smaller. In outline the section of hemisphaenda more 
nearly resembles that of Segmentina nitida (plate 47, fig. 23) than that 
of calathus. 

Digestive System. The stomach I'esembles that of Segmentina nitida 
(plate 48. fig. 16 1 but the blind sac is somewhat larger. The buccal sac 
is pyriform. with a large radula sac behind and two small salivary glands 
like those in Segmentina nitida. 

The jaw is like that of Segmentina nitida, segmented with many plates 
(plate 50, fig. 24). Polypylis calathics has a similar jaw with many small 
plates. 

The radula formula of hemisphaerula is 25-1-25 with over 200 rows of 
teeth. The teeth are like those of Polypylis calathus (plate 69. fig. 8). all 
6-cuspid. the cusps short and the reflections wide and low and placed high 
up on the teeth. In calathus the formula is 26-1-1-26 with 205 to 210 rows 
of teeth. The rows of teeth are all in straight lines, as in Segmentina. 

The above anatomical details were obtained from the following material: 
Polypylu hemisphaerula (Benson) from Peipino;, China, sent by the Fan Memorial 

Institute, Peiping, China. Four specimens. 
Polypyli.s calathu.'i (Benson), from weedv tank near inspection bungalow, Mongyai. X. 

Shan States, Burma. Collected by "Dr. H. S. Rao and Mr. B. H. Chopus. One 

specimen e.xamined. 
Polypylis tnia (Annandale and Rao), from below Machligaon. Port Blaie, Andamans. 

Collected by Dr. H. S. Rao. One specimen examined. 



106 The Molluscan Family Planorbidae 

Geographical Distribution. Polypylis is found throughout much of 
eastern China and India and on some of the islands lying off the coast of 
China and India. Its full distribution and the species belonging to it can 
not be fully known until more of the species from Asia have been anatomi- 
cally examined. 

Species Considered as Valid. The following species appear to be cor- 
rectly placed in this genus: 

Polypylis hemisphaerula (Benson) Polypylis swinhoci (H. Adams) 

Polypylis calathus (Benson) Polypylis taia (Annandale and Rao) 

Polypylis lucida (Gould) Polypylis usta (Gould) 
Polypylis nitidclla (Martens) 

Geological Distribution. Not ascertained. 

Remarks. Polypylis differs generically from Segmentina and Intha in 
the absence of a penial gland in the preputium. There is some variation 
in the form of the flagella in the species examined. In hemisphaerula 
there is but one flagellum on a long duct, while in calathus and taia there 
are two short flagella as in Segmentina. 

The shell of Segmentina differs notably from that of Polypylis, being 
flattened with an acute periphery, while the perijihery of Polypylis is 
rounded and the shell is high. The lamellae within the aperture in 
Segmentina are three in number, parietal, basal, and upper labial, all trans- 
verse to the whorl (plate 76, fig. 4). The space between the lamellae is 
narrow and three-cornered, quite unlike the wide space in the aperture of 
Polypylis (plate 76, fig. 5). 

The difference between the form of flagellum in the type sjiecies and 
the flagella of the other species examined from India and China might 
indicate a division into two groups, as suggested below. 

Group I. With one swollen flagellum on a long duct. 
Example: Polypylis hemisphaerula (Benson). 

Group II. With two short, narrow flagella without swollen end. 
Example: Polypylis calathus (Benson). 

Polypylis taia (Annandale and Rao) . 

However, too few of the Asiatic species have thus far been examined 
anatomically to warrant separation into subgenera at the present time. 

Genus HELICORBIS Benson, 1855 

1855. Helicorbis Benson, Jour. Asiatic Soc. Bengal, XXIV, p. 126. Subgenus of Pla- 
norbis. No type cited. The species Planorhis (Helicorbis) umbilicalis Benson, 
one of the original species listed, is here nominated as type of the genus. 

1906. Helicorbis Dall, Nautilus, XIX, p. 105. Considers group equal to Hippeutis 
{kg.) Charp., 1837. 

1921. Hippeutis Ann.-vnd.^le and Pr.\shad (non Charp., 1837), Rec. Ind. Mus., XXII, 

p. 584. Places Planorhis umbilicalis in this genus. 

1922. Hippeutis Annandale (non Charp., 1837). Rec. Ind. Mus., XXIV, p. 361. 

Mentions Planorbis iimbilicalis Benson as belonging in genus Hippeutis. 

1926. Helicorbis Kennard and Woodward, Syn. Brit. Non-Marine Moll., p. 69. Con- 
sidered synonym of subgenus Hippeutis. 

1931. Helicorbis Thiele, Handbuch, Teil 2, p. 481. Treated as synonym of Hip- 
peutis. 

Shell (plate 78, figs. 5-7) . Ultradextral, the body whorl wide and over- 
lapping or embracing the previous whorl, all whorls visible on upper (right) 



Subfamilies, Genera, and Subgenera — Recent and Fossil 107 

side, but mostly concealed on lower (left) side, the spire depression forming 
a false umbilicus. The whorls are rounded or at most only subangulate, not 
sharply carinate. Lips thin. There are no internal barriers or lamellae 
within the aperture. The embryonic whorls are marked as in other genera 
of the family. 

The figure of Plajwrbis umbilicalis in Clessin, Conch. Cab., XVII, Taf. 
15, fig. 6 does not rei)resent that species but is a good representation of the 
new genus PingicUa F. C. Baker. Germain (1921, p. 177) has called atten- 
tion to the discrepancy in Clessin's figure and gives good figures of 
umbilicalis on plate II, figs. 19, 20, and 21. The periphery in these figures 
is rather well-rounded. The figures in Hanley and Theobald, Conchologia 
Indica (1876), plate 40, figs. 7, 8, and 9 show the periphery as slightly 
carinated. Clench' and Beciuaert (1939) give the best figures observed 
(plate 1, figs. 8, 9, and 10) showing well the slight angulation of the 
l^eriphery. We can not agree, however, that Helicorbismearnsi Bartsch is 
a synonym of umbilicalis (see plate 2, figs. 10-12) ; it is too sharply 
angulated on the j^eriphery. It is evident that the species referred to the 
subfamily Segmentininae are in need of careful revision. 

Animal. 'The external soft parts generally resemble those of Gyraulus 
except that the branchial process and the pulmonary siphon are a little 
better developed' (Annandale and Prashad, 1921, p. 584). 

ANATOMICAL CHARACTERISTICS 

GENITALIA. 'The male genitalia generally approximate to Simroth's 
Typus I, but differ in details. The vas deferens is very long and coiled. 
The penis sac is a well-developed ovoidal structure with an elongated 
tubular preputium in continuation of the sac. The penis is massive with a 
lateral opening and without anv stylet' (Annandale and Prashad, 1921, 
p. 585). 

Radula. 'The radula is very minute and the dental formula is approxi- 
mately 14-12-1-12-14(26-1-26): The central tooth is comparatively large 
and bicuspid with sharp cusps. The laterals and marginals both have a 
peculiar twinned structure, and the line of demarcation between the 
laterals and marginals is not very sharp. The laterals are tricuspid, the 
central cusp much the largest' (Annandale and Prashad). The radula is 
figured on page 583 of the work cited (fig. 16B). The teeth are like those 
of Bathyontphalus and Hippeutis. The twinned nature noted for some of 
the teeth was not particularly apparent in the radula of Hippeutis com- 
planatus examined. 

Geographical Distribution. Not clearly known but including eastern 
and central China and India, the Philippines, and probably other islands 
off the cast coast of Asia. 

Species Considered as Valid. Just what species may be included in this 
genus is not definitely known. The following are believed to belong here: 

Helicurbis umbilicalis (Benson) Helicorbis mearnsii^Sirtsch) 

Hclicorbis caenosus (Benson) Helicorbis papyraceus (Benson) 

Geological Distribution. Not ascertained. 

Remarks. The Segmentina-like shells of India and China referred to 
Hippeutis are apparently not like the type of that genus, Hippeutis com- 
planatus (Linn.), at least as far as the shells are concerned. Both agree in 



108 The MoUuscan Family Planorhidae 

lacking internal barriers or lamellae in the aperture. The shell of com- 
planatus, however, is lenticular with a sharply angular peripheral keel and 
the aperture is longitudinally triangular, wider than high. Helicorbis, 
on the contrary, has a higher shell with rounded or subangular whorls ancl 
the aperture is oblique and higher than wide. 

The published description of the anatomy of this group (the type, 
Planorbis umbilicalis) is insufficient for the purpose of making comparisons 
with Hippeutis complanatus, as no mention is made of flagella, penial 
gland, or prostate. The penis (verge) is said to have its sperm canal open- 
ing on the side, which is like that of Hippeutis (see plate 2, figs. 5, 6) . Until 
more is known of the genitalia of Planorbis umbilicalis, the group Heli- 
corbis had better be considered a separate genus related to Hippeutis. 

The name Helicorbis has been almost unnoticed since its publication in 
1855. Dall (1905) overlooked it in his Alaska Mollusks but later (1906) 
he considered it equal to Hippeutis Agassiz, 1837. Germain (1921) omits 
all reference to it. Kennard and Woodward make it a synonym of 
Hippeutis (1926), as does Thiele (1931). Bartsch, in a paper on Philippine 
mollusks (1907, p. 84), places a related species in Helicorbis, the latter 
treated as a subgenus of Planorbis. Bequaert and Clench in a later paper on 
Philippine Lymnaeidae and Planorbidac (1939, p. 16) place Planorbis 
umbilicalis in Hippeutis, which is recognized as a genus. 

In Benson's paper (1855, p. 126) three species are mentioned under 
Helicorbis; hemisphaerula and nitida are ruled out by the remark in the 
paragraph above concerning Secjmentina (of which nitida is the type) 
which refers to the internal divisions or barriers. Hemisphaerula, also, is 
the type of Pilsbry's Polijpylis. There remains the species umbilicalis 
which has not previously been used as a type for any group and this is here 
nominated for the type of Helicorbis Benson. 

Helicorbis may bear something of the same relationship to Hippeutis 
that Polypylis bears to Segmentina, although the anatomical differences 
between the last two groups are greater than appears to be the case of the 
first two groups. 

Genus TROCHORBIS Benson, 1855 

Type by original de.signation Trochorbis trochoideus Benson 

1855. Trochorbis Benson, Jour. Asiatic Soc. Bengal, XXIV, p. 126. Type Trochorbis 

trochoideu.s (Benson). As subgenus of Planorbis. 
1906. Trochorbis Dall. Nautilus, XIX, p. 105. Type Planorbis trochoideus Benson. 

As subgenus of Planorbis. 
1927. Trochorbis Kenn.ard and Woodward, Syn. Brit. Non-Marine Moll., p. 90. No 

type cited. Considered a synonym of Segmentina. 

Description of the type of the genus Planorbis trochoideus Benson: 
'Testa vix perforata, diaphana, nitida, inconspicue radiato-striata, subtro- 
chiformi, convexa; spira parvula, arete convoluta, concava; sutura pro- 
funde impressa; anfractibus 3i/{>, penultimo valde convexo, ultimo majori, 
versus suturam obtuse angulato, extus depresso, interne acute carinato, 
intus laminis rarissimis jileurumque minuto, subtus piano, medio, versus 
umbilicum inconspicuum, leviter excavato, versus periphaeriam vix declivi; 
apertura oblic|ua subsagittata, marginc suj^criori arcuato, jn'ominente, 
inferiori recidente. Diam. 3 mm., axis vel 2' (Benson, 1850, p. 352). 

'The infrequency and irregularity of the internal laminae in this species, 
causing them to look more like accidental thickenings of the shell, made 



Subfamilies, Genera, and Subgenera — Recent and Fossil 109 

me overlook this structure in my original description. The species is singu- 
lar from the nearly total absence of umbilicus' (Benson, 1850, p. 352). The 
shell is treated as dextral (ultradextral). 

Animal. The anatomy of this species is at present unknown. 

Geographical Distribution. Barrackpore, Bengal, India. 

Species Considered as Valid. Trochorbis trochoidcus Benson, the 
genotype, is the only species assigned to this genus. 

Remarks. In 1850 (p. 352) Benson noted the trochoid form and small 
umbilicus of Pkuwrbis trochoidcus and in 1855 (p. 126) erected the group 
Trochorbis for it. This name has l)een overlooked by most writers on 
Asiatic mollusks. Dall (1906, p. 105) considered Trochorbis a synonym 
of Secjmentina. In Preston's Fauna of British India (1915, p. 125) the 
species appears as Planorbis iSegmentina) trochoideus without reference 
to its use as type of Trochorbis. Germain (1921, p. 175) does not mention 
the group name proposed by Benson and places the species trochoidcus in 
the genus Segmentina. Kennard and Woodward (1926, p. 90) consider it 
an absolute synonym of Segmentina. Trochorbis is not recognized by 
Annandale and his co-workers in the studies of the mollusk fauna of the 
Indian Empire. 

Typical Segmentina is not found in eastern Asia, the species previously 
referred to that genus now being placed in the genus Polypylis of Pilsbry. 
Trochorbis trochoideus greatly resembles Plartorbis calathus Benson which 
belongs to the genus Polypylis and from the shell characters appears to 
be only specifically distinct from calathus, U one can judge from the very 
excellent figures of both species in Hanley and Theobald, Conchologia 
Indica, plate 39, figs. 1-3 (calathus) and 4-6 (trochoideus) . 

The species trochoideus has a much smaller shell than calathus and the 
periphery is more acute. According to Benson, the apertural lamellae are 
so weak that he overlooked them in his first description of the species. 
The Asiatic mollusks allied to Segmentina have shown such diversity in 
anatomical characteristics that until the animal of trochoideus is examined 
it seems best to treat Trochorbis as a separate genus. Its place, as far as 
can be judged at present, is near the group of shells called Polypylis, with 
the internal lamellae far within the aperture. 

Genus PINGIELLA F. C. Baker, New Genus 
Type Pyramidula (P alula) peipinensi.^ Ping and Yen 

1932. Pyramidula (Patula) peipineiisis Ping and Yen, Bull. Fan Memorial In.st. Biol., 
Ill, p. 25, figs. 1-3. Wrongly interpreted as a land shell. 

1938. Ani-fu.^ (Hippeutis) peipinenf^is Mori, Mem. Col. Sci., Kvoto Imp. Univ., Ser. B, 
XIV. Xo. 2, p. 288, plate 14, fig. 6. 

Shell (plate 78, figs. 8-10). Ultradextral, lenticular, flattened, with 
sharp i^eripheral carina, the last whorl very large and strongly overlapping 
or clasping the preceding whorls, the base flattened, with a narrow spire 
dejiression exhibiting all of the whorls, the depression about one third of 
the diameter of the shell. Aperture without internal lamellae. Major 
diameter of shell 7.8 mm. to 8.6 mm. The embryonic whorls are pitted. 

Animal. Foot and pneumostome lead color, body yellowish finely 
mottled with black. Kidney pigmented (from alcoholic specimens). 



110 The Molluscau Family Planorhidae 

ANATOMICAL CHARACTERISTICS 
PLATE 4 

GENITALIA. Male Organs (plate 4, fig. 9) . Seminal vesicle (SV) large, 
tortuous, more than double the diameter of the ovisperm duct, with several 
vesicles, but mostly tubular. Sperm duct, long (3.5 mm.), narrow. Prostate 
(PRS) about 2 mm. long with twenty to twenty-two long diverticula. 
Free portion of prostate duct very short. Vas deferens long (4 mm.) and 
tubular. 

Penial complex (fig. 5) with a large, sac-like preputium (PR) and 
small, narrow, short (little more than 0.5 mm.) vergic sac (VS). The 
vergic sac is placed on the side of the upper part of the preputium. There 
are two flagella, short and wide, placed on tube-like ducts longer than 
the whole penial complex. The sac-like flagella (FL) are turned hori- 
zontally to the tube-like duct. There is a very long and very fine, tube-like 
external penial duct ( DC ) , about three times as long as the penial complex 
when stretched to its fullest extent. There is a single, wide retractor 
muscle (R]\I) attached about midway of the i:)reputium at the point where 
the penial duct has its exit. 

Internally (plate 4, fig. 6) ,. there is a short, wide pilaster which bi- 
furcates about midway of the preputial cavity, one branch forming a wide, 
flat gland (GL) which is doubled backward at the end (fig. 6). The other 
branch is short and narrow and ends above in a rounded, disc-like 
organ (G). The very long duct (DC) which appears on the outside of the 
preputium, enters a canal in this small branch (fig. 2, C, fig. 7, C) which 
terminates on the underside of the reflexed end of the gland (fig. 7, GL). 
Tlie other end of the penial duct passes on the outside of the small pilaster 
and enters the round, turban-like termination of the small pilaster (figs. 
2, 6, G and DC). There is a thickened muscular ring or diaphragm be- 
tween the vergic space and the preputial space (figs. 6, 8, D). The retractor 
muscle is attached to the preputium near the small liranch of the pilaster 
(fig. 6, RM). 

The verge (fig. 8, V) is long and narrow, swollen or pear-shaped at the 
upper part but narrowed and tubular below. The lower end of the verge 
is notably flattened and broad, with a small penial papilla at the end, just 
beside the sperm canal exit, which is in the center of the verge (figs. 3, 4). 
The sac-like portion of the flagella is large and the cavity is lined with 
elliptical cells which show on the exterior surface as small, rounded pro- 
jections (fig. 5, PL). The duct of the flagellum is narrow but is of greater 
diameter than the vas deferens. 

Female Organs, The spermatheca is globe-shaped (S) with a short, 
narrow duct about as long as the greater diameter of the spermatheca 
(SD). Another specimen had a spermatheca long and sac-like (fig. 5, plate 
5) attached to the vagina by a very short wide duct. This spermatheca 
contained a spermatophore and the specimen was evidently in gravid con- 
dition. The form of the spermatheca evidently varies with the breeding 
condition of the animal. Vagina rather short but longer than wide (VG). 
Uterus (U) short and as narrow as the vagina. Nidamental gland (NG) 
veiy long (3 mm.) and much swollen. Oviduct (OD) short and narrow. 
Albumen gland ( fig. 1 ) elongated, about twice as wide as long, placed 
over the stomach, the intestine looped beneath it. 



Subfatnilies, Genera, and Subgenera — Recent and Fossil 111 

Hermaphrodite Organs. The ovotestis (OT) consists of many long and 
narrow diverticula placetl in a double series. The ovisperni duct (SO) is 
of small diameter. The portion between the seminal vesicle and the ovo- 
testis is very short (less than 1 mm.) but the portion between the seminal 
vesicle and the oviduct is very long (about 3 mm.). 

An egg capsule on one of the shells, presumably of this species, con- 
tained eight eggs. 

Respiratory and Renal Systems. The pseudobranch (plate 5, fig. 1, P) 
is small and inconsjncuous, resembling that of Hippenfis. 

Tiie kidney is long and narrow, resembling that of Segmentina, but not 
as long. The ureter is directed horizontally into the mantle cavity, not 
reflected. There is no superposed ridge. A section of the kidney near the 
middle shows a wide and low lumen about three times as wide as high 
with the veins at the upper corners. A section below the middle shows a 
flatter form with the lumen almost as high as wide and somewhat tri- 
angular, the veins at the upper part of the triangle. This triangular form 
is caused by the acute angle of the shell on the periphery. 

Digestive System. The stomach is long and narrow as in Segmentina, 
the intestine making a loop around the stomach and another around the 
liver and then passing forward to the rectum and pseudobranch. The blind 
sac is very short and pointed below. 

The buccal sac is elongated, pear-shaped, the radula sac large and near 
the middle of the posterior end. The salivary glands extend considerably 
beyond the rear end of the buccal sac and are united behind; the ducts 
are small and tube-like. 

The jaw is fragmented with about eighty plates. It is horseshoe-shaped 
as in the other groups of this subfamilv. 

Radula formula 26-1-26 with 160-170 rows of teeth. The teeth resemble 
those of Segmentina and Polypijlis (see j^late 69, figs. 7, 8). The laterals 
have six short, spade-shaped cusps and the marginals have seven 
short cusps. 

The anatomical details have been obtained from three specimens 
from Peiping, China, received from the Fan Memorial Institute of Peiping, 
through the courtesy of Dr. Chi Ping. 

Geographical Distribution. Northern and eastern China and Japan. It 
is probable that this distribution will be extended when more material has 
been examined from China and India. 

Geological Distribution. Unknown. 

Species Considered as Valid. Pingiella peipinensis (Ping and Yen), 
the genotype, is the only representative of this monotypic genus. 

Remarks. This genus is remarkable for the peculiar characteristics of 
the penial comj^lex, the penial gland, bifurcated into a large and a small 
branch, the latter with a turban-shaped termination, and the very long, 
tube-like external duct with its peculiar gland terminations. The terminal 
end of the verge is also peculiar. The flagella are notable in having the long 
ducts and the small, sac-like glands. These differences are sufficient to 
stamp the species as belonging to a new and hitherto unknown generic 
group. It differs from Segmentina in the possession of an external duct 
and from Polypylis by having a penial gland which is absent in that genus. 



112 The Molluscan Family Planorhidae 

It is quite probable that other species belong in this genus and will be 
discovered when examined anatomically. 

Mori ( 1938, p. 288) has called attention to the fact that this species is 
a planorbid and not a land shell. He, however, places the species in the 
genus Anisus, subgenus Hippeiitis, following the classification of Thiele. 
The anatomy, especially the genitalia, indicates that this species can not 
correctly be referred to either Anisus or Hippeutis, differing widely in its 
internal organization. 

The genus is dedicated to Dr. Chi Ping, research professor in the Fan 
Memorial Institute of Biology, Peiping, China, an accomplished student of 
the Asiatic molluscan fauna. Dr. Ping has supplied the author with a num- 
ber of mollusks for anatomical study from near Peiping. 

Genus IXTHA Annandale, 1922 

Type b}^ original designation Intha capitis Annandale 

1922. Intha Ann.^nd.^le, Rec. Ind. Mus., XXIV, p. 361. Type hitha capitis Annandale. 
As genus. 

1931. Intha Thiele, Handbuch. Teil 2. p. 482. Anisus (I.) capitis (Annandale). As sub- 
genus under genus Anisus. 

Shell. Tn this genus the body-whorl, though relatively smaller than it 
is in Hippeutis, completely embraces- and occludes the rest of the shell in 
such a way that the spire is entirely concealed, except in so far as it can 
be detected by transparency. The shell is very minute and has few whorls, 
which increase in size rapidly. Those of the spire are cylindrical, but the 
body whorl is flattened below and has the form of a flattened conoid 
slightly truncate above. The outer lip arises in the middle of the upper 
surface and forms a small lobe at its point of origin. The aperture is large 
and very oblique but with a cordate outline. There is a well-developed 
simple callus on the inner lip, but internal ridges are completely absent. 
The lower surface is narrowly umbilicate. The external surface is prac- 
tically smooth' (Annandale, p. 361). The shell is ultradextral. No figure of 
the shell is available and the single specimen used for dissection had the 
shell badly broken which made it unfit for illustration. 

Animal. 'The animal is remarkable externally for the large upper and 
lower lobes into which the mantle is divided. The pseudobranch is poorly 
developed' (Annandale, p. 362). The head of the animal bears short, blunt 
tentacles (plate 8, fig. 3). 

AXATOMICAL CHARACTERISTICS 
PLATE 8 

GENITALIA. Male Organs (fig. 11). Seminal vesicle (SV) very large, 
about three times the diameter of the ovisperm duct, with a few irregular, 
pointed, glandular projections. It is less than 1 mm. long. Sperm duct 
(SPD) long (slightly more than 1 mm.) and of large diameter. Prostate 
short, with six large, club-shaped diverticula. Prostate duct (free portion) 
about as long as the prostate. Vas deferens (VD) of small diameter and 
very long (about 5 mm. when stretched out). 

The penial complex has a large, bulbous preputium (PR) and a small, 
slender vergic sac (VS), somewhat shorter than the preputium (fig. 6). 
Together both organs measure 1 mm. in length. There is a short, narrow 



Subfamilies, Genera, and Subgenera — Recent and Fossil 113 

penial gland duct on the outside of the i)reputiuni, emerging from the 
latter about midway between the outlet and the summit of the preputium. 
At the upper end of the vergic sac there are two very large fiagella (about 
1 mm. long) which are sausage-shaped and are attached to the vergic sac 
by a very short duct, in fact they are almost sessile. Small glands on the 
interior of the fiagella show through as white circles, as shown in the 
figure (fig. 11, FL). There is a wide retractor muscle which is attached to 
the upper part of the preputium. 

Internally (fig. 8), the preputium has a large penial gland (GL) which 
is attached to the preputium only at its base, the cup being free. It is more 
or less circular in shape, depressed, with a wide cup-shaped depression in 
which the walls are ridged (probably glandular). There is a short duct, 
external to the 'preputial cavity, which enters a round, fleshy ring or 
diajihragm between the vergic and jn-eputial cavities (fig. 8, D). The rela- 
tionship of the gland and duct to the preputial sac is well shown in fig. 7. 
The verge (V) is narrow, tapering, with the exit at the end in the center. 
There is a very small papilla at one side of the opening (fig. 4). The two 
fiagella are joined in one tube before thev enter the vergic sac (fig. 11, VS; 
fig. 8. FL). 

Female Organs (fig. 11). The spermatheca (S) is large and almost 
circular, and is joined to the short, wide vagina (V) by a duct which is 
shorter than the diameter of the spermatheca. The uterus (U) is wide and 
shorter than the spermatheca and its duct. The nidamental gland (NG) is 
very wide, sac-like, and about twice as long as the uterus. The oviduct 
(OD) is short and wide, about as long as the preputium. There is a large 
carrefour (CF). The albumen gland (AL) is large, about 1 mm. long, and 
has a space for the passage of the intestine (fig. 1) . 

Hermaphrodite Organs. The ovotestis (OT) is large with the diver- 
ticula long and clul)-shaped. They are placed in a double series. The ovi- 
sperm duct (OS) is very short between the seminal vesicle and the 
ovotestis and about 1 mm. long between the seminal vesicle and the ovi- 
duct. A spermatophore of peculiar form was found in the spermatheca 

No figure or descri]ition has been published of the genitalia of this 
genus. Annandale says of the genitalia: 'The male organ resembles that of 
Planorbis, except that the penial bulb is relativelv verv large' (op. cit., 
p. 362). 

Respiratory and Renal Systems. The pseudobianch (fig. 2, P) is a 
flatly rounded, simple lobe, pierced above by the rectum. The kidney (plate 
47, fig. 26) is wide and fiattened and not as long as in Segmentinn or 
Poh/pi/Us. There is no superposed ridge. In section (fig. 27) the lumen is 
long, oval in outline with the veins about in the center on each side. 

Digestive System. The stomach is narrow as in Segmentina, the intes- 
tine making the same loops around the stomach and liver as in the genus 
Segmentina. The buccal sac resembles that of Segmentina. The jaw (plate 
50. fig. 23) is fragmented as in Segmentina. There arc more than sixty 
plates on the jaw. 

The radula has the formula 15-1-15 with over 125 rows on a liroken 
membrane (iilate 69, fig. 9). Center tooth bicuspid, the cusps not reaching 
the lower margin of the base of attachment. Lateral teeth (1-5) with two 



114 The MoUuscan Family Planorhidae 

entocone cusps, a single raesocone, and three ectocone cusps, the mesocone 
a trifle larger than the other cusps. Marginal teeth 7-cuspid (6, 8, 11, 12) 
with three small cusps on each side of a mesocone cusp. There are no 
intermediate teeth. The teeth are all in a straight row. They are very 
uniform in size and shape but become narrower toward the outer edge 
of the membrane. The teeth are essentially like those of Segmentina. 

For the above anatomical details a single specimen was dissected, 
received from Dr. H. S. Rao, collected by Dr. N. Annandale in Inle Lake, 
southern Shan States, Burma. 

Geographical Distribution. Known at present onlv from the tvpe 
locality, He-Ho and Inle valleys (3000-3800 ft. alt.) southern Shan States, 
Burma. Recent and fossil. 

Species Considered as Valid. Intha capitis Annandale is the only 
species recognized for this monotypic genus. 

Remarks. Intha is peculiar in the form of its shell and also in the 
characteristics of its genitalia, with the few prostate diverticula of large 
size, the two enormous flagella, and the striking penial complex with a 
penial gland which has a small, short duct entering the circular ring be- 
tween the vergic sac and the preputium. In this respect it resembles some 
of the Helisomatinae (typical Helisoma) but differs in the form of the 
prostate and ovotestis. It appears to be another peculiar variant of the 
Segnientina group of Planorbidae. 

Genus DREPANOTREMA Fischer and Crosse, 1880 

Monogenotype Planorbis yzabolensis C. and F. (= Pkinorbis anatinum d'Orbigny) 

1880. Drepanotrema Fischer and Crosse, Miss. Scient. Mex., Moll., II, pp. 59, 75. 
Type Planorbis yzabalensis C. and F. As subgenus. 

1883. Drepanotrema Fischer, Man. de Conch., p. 509. Type Planorbis yzabalensis 

C. and F. As section of Planorbis. 

1884. Drepanotrema Tryox, S. and S. Conch., Ill, p. 107. Type Planorbis yzabalensis 

C. and F. As subgenus of Planorbis. 

1884. Bathijomphalus Tryon (non Agassiz, 1837), S. and S. Conch., Ill, p. 106. Pla- 

norbis anatinus Orb., cited as example. 
1884. Ayiisus Tryon (non Studer, 1820), S. and S. Conch., Ill, p. 106. Planorbis 

kertnatoides Orb., cited as example. 
1899. Drepanotrema M.artexs, Biol. Cent. Amer., Moll., p. 397. As synonym of 

Hippe litis. 

1899. Spiralina M.^rtexs, (part) op. cit., p. 395. Includes Drepanotrema cultratum 
and sumichrasti. 

1899. Hippeutis Martens (non Agassiz, 1837), op. cit., p. 397. Cites Plaiiorbis yzabal- 
ensis, type of Drepanotrema. 

1905. Drepanotrema D.\ll, Alaska Moll., p. 82. Type Planorbis yzabalensis C. and F. 
As section of subgenus Hippeutis. 

1921. Drepanotrema Germain, Rec. Ind. Mus., XXI, p. 8. Type Planorbis yzabal- 
ensis C. and F. As subgenus of Planorbis. 

1930. Drepanotrema H. B. Baker, Oc. Papers, Mus. Zool., Univ. Mich., No. 210, 

pp. 43, 38, 51. Type Planorbis yzabalensis C. and F. As genus. 

1931. Drepanotrema Thiele, Handbuch, Teil 2, p. 481. Type Drepanotrema yza- 

balensis C. and F. Section of Gyraulus, subgenus of Planorbis. 
1934. Drepanotrema Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 58. Type Planorbis 
yzabalensis C. and F. As genus. Figures genitalia of D. lucidum (Pfr.) and 

D. cultratum (Orb.). 



Subfa/fnlies, Genera, and Subgenera — Recent and Fossil 115 

Shell (plate 79, figt;. 16-18). Small, iiltradextral, of few whorls, the body 
whorl large and expanded, embracing the previous whorl; whorls rounded 
or carinated; the right side with whorls sunken below the upper surface or 
showing a wide, slightly concave depression. There are no barriers or 
lamellae within the aperture. The embryonic shell is punctate. 

Animal. The body is long and narrow, rounded before and sharply 
pointed behind. The tentacles are long and filiform, the eyes large and 
conspicuous, placed at the inner base of the tentacles. There may be two 
dark lines of color extending down the neck and top of the head. In some 
species (as melleus Lutz, plate 78, figs. 1, 2) the body is not much pig- 
mented, but in some others (as hoffmani F. C. Baker, plate 10, fig. 1) the 
l)ody is dcei^ly jngmented with black. 

ANATOMICAL CHARACTERISTICS 
PLATES 9, 10, 11 

GENITALIA. Male Organs (plate 9, fig. 2; plate 10, fig. 2; plate 11, 
fig. 3, respectively anatinum, hoffmani, and lucidum) . Seminal vesicle (SV) 
large, much elongated, swollen, two to three times the diameter of the 
ovisperm duct, varying in length in the three species examined. It is about 
half the length of the ovisperm duct region in hoffmani but only about a 
third of this lengi:li in lucidum. Anatinum is much like hoffmani. The 
prostate (PRS) varies greatly in the three species: in hoffmani it is 3.5 
mm. long and is made up of twenty-three short, club-shaped, widely spaced 
diverticula; in lucidum, there are but eight diverticula on a prostate about 
1 nun. long; in anatinum, there are seven diverticula still more widely 
sjiaced and the prostate is about 1 mm. long. All diverticula arise directly 
from the sperm duct and are not on a separate duct as in Segmentina and 
other members of the subfamily. 

The sperm duct (SPD) also varies in length, being 5 mm. in hoffmani, 
2.3 mm. in lucidum and a little over 1 mm. in anatinum. These lengths do 
not include the sperm duct portion under the prostate diverticula. The 
vas deferens of the three species is always a long, narrow tube, varying in 
length in the different species. 

The penial comi~)lex is much elongated in all species examined. In 
hoffmani (plate 10, fig. 5) the preputium is elongated, cylindrical, and 
about twice the diameter of the long and narrow vergic sac, which is 
nearly twice the length of the preputium. In lucidum, the preputium is 
about three times the diameter of the vergic sac, which is considerably 
longer than the preputium (plate 11, fig. 4). In another specimen, the 
preputium and the vergic sac were about equal in length (plate 11, fig. 51. 
In anatinum (plate 9, fig. 1), the vergic sac is shorter than the preputium, 
which forms a reversed cone, becoming smaller in diameter toward the 
ui^i^er part. 

The flagella of the three species differ considerably. In hoffmani (plate 
10, figs. 6, 7, 8), the flagcllum is very short and is bifid at the end; in 
lucidum (plate 11, figs. 4, 5), the flagellum is very long (1 mm. or more) 
and is not bifid at the end; in anatinum (plate 9, fig. 1), the flagellum is 
as long as the preputium (0.6 mm.) and is bifid at the end. A strong 
retractor muscle is attached to the end of the vergic sac near the 
insertion of the flagellum (plate 10, fig. 7). There is also a large nerve 
at this point (N). 



116 The MoUuscan Family Planorhidae 

Internally, the penial complex is simple in all species studied and re- 
sembles the condition observed in hoff)nani (plate 10, fig. 6). There are 
three rather heavy pilasters, a small muscular ring or diaphragm between 
the preputium and the vergic sac, and a very long verge completely 
filling the vergic sac (V). The verge is narrow at the end with a central 
sperm outlet (plate 10, fig. 9). 

Female Organs. These also differ in the three species. In hofjmani 
(plate 10, fig. 2 1 the spermatheca is pyriform and is joined to the long and 
narrow vagina by a duct twice as long as the spermatheca; in lucidum the 
spermatheca (plate 11, fig. 3) is globular, much wider than in hoffmani, 
and is connected with the vagina (which is shorter than in hoffmani) by a 
duct a trifle longer than the spermatheca; in anatinum (plate 9, fig. 2) the 
spermatheca is wider than in hoffmani but not as globular as in lucidum 
and is attached to the narrow vagina by a duct almost three times as long 
as the spermatheca. The uterus (U) is very long and narrow in hoffmani, 
shorter and wider in lucidimi, and narrow in anatinum. 

The nidamental gland is long and wider than the uterus in all three 
species. The oviduct (OD) is very long and narrow in hoffmani (about 5 
mm. long), much shorter in lucidum (about 2 mm.) and very short in 
anatinum (less than 1 mm.). There is a small and inconspicuous carrefour 
(CF) in all species. The albumen gland is much elongated (plate 10, fig. 4). 

Hermaphrodite Organs. The ovotestis (OT) consists of a few club- 
shaped diverticula placed in a double series. The ovisperm duct is much 
longer in lucidum than in either hoijmani or anatinum (see plate 9, fig. 2; 
plate 10, fig. 2; plate 11, fig. 3). 

Several specimens of lucidum had the male genitalia completely everted 
and lying on the body of the animal (see plate 11). In fig. 1, the preputium 
is fully everted and the verge is extended to its fullest extent. In fig. 2, 
only the preputium is everted. In fig. 6, the organs are diagrammatically 
shown so that the relationship of the different parts may be seen under 
this condition. The flagellum, vergic sac, vas deferens, and retractor muscle 
remain in the body of the animal just behind the male ojiening. This is 
shown to better advantage in fig. 7. 

Pilsbry (1934, p. 59, fig. 6, F) figured the penial complex of lucidum 
(from sketches by H. B. Baker). This figure differs from the specimens 
here examined in having a shorter flagellum and in having the penial re- 
tractor attached to the preputium instead of to the vergic sac. In all speci- 
mens of Drepanotrema examined, the retractor muscle was inserted at the 
end of the vergic sac near the flagellum and not at the summit of the 
preputium. As shown in fig. 8 on plate 10 [hoffmani) , the vas deferens, 
flagellum, and retractor muscle may be so closely pressed together and 
bent downward at the summit of the preputium that relationship of the 
muscle is difficult to see clearly unless the parts are separated, as shown in 
fig. 4, plate 11 {lucidum). All specimens were torn apart to insure 
accuracy in this statement. 

Pilsbry also figured the penial complex of Drepanotrema cultratum 
(Orb.) (plate 76, fig. 10) which is similar to that of lucidum, the vergic sac 
being but a trifle shorter than the preputium. The flagellum is somewhat 
more than half as long as the vergic sac. Pilsbry 's figures are the only ones 
previously published on the anatomy of Drepanotrema. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 117 

Respiratory and Renal Systems. Tlie pseu(l(jl)rancli (P) is a somewhat 
triangular i)ro('ess in lucidum (plate 11, figs. 1, 2) and anatinuni (plate 9, 
fig. 3) but in ho)J))iani appears to be narrower and more cylindrical (plate 
10, fig. 3). The rectum is very large and the anus discharges just above the 
base of the pscudobranch. The pneumostome is very large (PS). 

The kidney of Drepanotrema hoffmani (plate 46, fig. 14) is very long 
and ribbon-like (15 mm. long). The ureter is very short and curves upward 
at right angles to the long axis of the kidney. A cross section near the 
middle (fig. 15) shows the kidney to be much flattened, the lumen wider 
than high, and the veins flattenecl and elongated in section. The kidney of 
lucidum is shorter and a section near the middle shows it to be more 
flattened than hoffmani, the lumen regularly long-ovate and the veins 
smaller and more 'regular in form (fig. 16). 

Digestive System, The stomach (plate 48, fig. 11) is pyriform, the 
pyloris tapering to the intestine, which forms a loop over the oesophagus 
and another loop around the liver as in other genera of the subfamily. The 
blind sac is two-thirds as long as the stomach. The buccal sac is similar 
to that organ in Tropicorbis. 

The jaw is horseshoe-shaped and is composed of many small plates 
arranged somewhat as in Planorbis. About seventy plates were counted 
on a jaw of lucidum (plate 50, fig. 27) and about as many on a jaw of 
hoffmani (]ilate 50, fig. 26). 

The radula formula of anatinum. (plate 68, fig. 3) is 18-1-18 with 158 
rows of teeth. Center tooth squarish with two long, spade-shaped cusps 
reaching two-thirds of the way to the lower margin of the base of attach- 
ment. There is a very small cusp on each side of the center cusps high up 
on the reflection. Lateral teeth (1-6) very wide, with three long cusps, 
entocone, mesocone, and ectocone. Above the entocone there is a small 
additional cusp, and above the ectocone there is another small cusp on the 
first four laterals and two cusps on the 5th and 6th laterals. The inter- 
mediate teeth (7-10) are very wide with the three main cusps well-de- 
veloped and with a small cusp above the entocone and a small interstitial 
cusp between the mesocone and the ectocone. Above the ectocone there are 
four small cusps on the outer margin of the teeth. The marginal teeth 
(11-18) are narrower than the intermediate teeth; there is a long entocone 
and mesocone with a small cusp above the entocone, three cusps between 
the entocone and mesocone, and five small cusps on the outer margin of 
the tooth where the ectocone would normallv be. 

In lucidum (plate 68, fig. 2), the formula is 28-1-28 with 240 rows of 
teeth. The center tooth is like that of anatinum except that the large cusps 
are longer. The lateral and marginal teeth are similar to those of anatinum 
except that the cusps are longer. 

In hoffmani (plate 68, fig. 4), the formula is 27-1-27 with 230 rows of 
teeth. The center tooth is as in lucidum and anatinum. The lateral and 
marginal teeth are similar to those of the other species figured. 

Dr. H. B. Baker (1930, p. 50) has examined the radula of ahcnum and 
says 'The radula and jaw of D. ahenum are also much as in D. lucidum. 
The radula formula is 30-1-30, with 194 transverse rows. The marginal 
teeth are slightly broader at the tip of the cusped reflection and may 
develop two interstitials between the entocone and mesocone.' 



118 The MoUuscan Family Planorhidae 

The radula teeth of Drepanotrema are peculiar in the possession of the 
small interstitial cusps between the larger cusps. They somewhat resemble 
the multicuspid teeth of Segmentina, Hippeutis, Intha, etc., to which the 
genus is also allied by the presence of a fiagellum. The radula of Drepano- 
trema is very uniform in the shape of the teeth, varying principally in 
the number of interstitial and accessory small cusps. The formulae, as well 
as the number of lateral and marginal teeth, vary in the different species. 

For the above anatomical data, three species have been examined: 

Drepanotrema anatinum (Orb.) Pueblo Viejo, Puerto Rico, collected by Dr. W. A. 

Hoffman. Five specimens dissected. 
Drepanotrema hoffmani F. C. Baker. Isabela, Puerto Rico, collected by Dr. W. A. 

Hoffman. Eight specimens dissected. 
Drepanotrema lucidmn (Pfeiffer). Havana, Cuba. Received from Dr. C. G. Aguayo. 

Five specimens dissected. 

Geographical Distribution. This genus is found more or less abun- 
dantly from southern Texas southward through Mexico and Central 
America to Brazil, Bolivia, and the Argentine Republic. It it also found 
in many of the West Indies Islands. It is jnirely an American genus and 
a number of species are known, including some names now considered 
synonyms. 

Pilsbry (1934, p. 59) divided the genus into three sections, Drepano- 
trema proper, Fossidorbis Pilsbry, and Platytaphius Pilsbry. In the writer's 
opinion, the last section should be regarded as a separate genus until the 
type has been dissected and its anatomy made known. The other groups 
divide the genus Drepanotrema into two comprehensive subgenera. 

Subgenus DREPANOTREIVIA Fischer et Crosse, 1880 

Spire on the right side, narrow and deeply sunken; periphery broadly rounded (type 
Drepanotrema anatinum (Orh. )= Planorbis yzabalensis C. and F. (Pilsbry) 

Species Considered as Valid. 

Drepanotrema aruitiniun (Orbigny) Drepanotrema chittyi Aguayo 

Plate 79, figs. 16-18 Drepanotrema parapseide (Orbigny) 

Drepanotrema lucidmn (Pfeiffer) Plate Drepanotrema ahenum H. B. Baker 

78, figs. 11-13 Drepanotrema castaneonitens (Pils. 

Drepanotrema hoffniani F. C. Baker and Van.) 

Plate 78, figs. 14-16 Drepanotrema melleum (Lutz) 

Subgenus FOSSULORBIS Pilsbry, 1934 

Having a wide spiral on the right side, very slightly concave; the periphery from 
rounded to carinate. Type Drepanotrema cultratum ((Drb.) Pilsbry. 

Species Considered as Valid. 

Drepanotrema (Fossidorbis) cultratum Drepanotrema (Fossulorbis) cimex(M.ori- 

(Orbigny) Plate 78, figs. 17-19 cand) 

Drepanotrema (Fossulorbis) c. anitense Drepanotrema (Fossulorbis) c. pistiae 

(Cooper) H. B. Baker 

Drepanotrema (Fossulorbis) c. duenasi- Drepanotrema (Fossulorbis) depressissi- 

anum (Tristram) mum (Moricand) 

Drepanotrema (Fossulorbis) c. labrosum Drepanotrema (Fossulorbis) kermatoide 

Pilsbry (Orbigny) 

Drepanotrema (Fossulorbis) c. panuco Drepanotrema (Fossulorbis) sumichrasti 

Pilsbry (Crosse and Fischer) 

Remarks. Drepanotrema differs in its genitalia and radula from all 
other American groups of Planorbidae. By its prostate, the diverticula 



Subjainilies, Genera, and Subgenera — Recent and Fossil 119 

club-^licii)ed aiitl placed in a ^^iiigle row on the sperm duct, it is allied to 
the subfamily Segmentininae. The jirostate differs from the members of 
both Planorbinae and Segmentininae in having the diverticula placed di- 
rectly on the sperm duct instead of on a separate prostate duct. The 
presence of the fliagellum on the vergic sac places Drepanotrema near the 
Euroixnm and Asiatic groups Segmentina, Polypylis, Hippeutis, and Intha. 
The nature of the rachda also indicates relationship with these groups. 
Although dei)arting from these groups in having the diverticula of the 
prostate placed directly on the sperm duct, the other characteristics place 
the genus in the subfamily Segmentininae with little doubt. 

The form of the shell of typical Drepanotrema bears close resemblance 
to the edentate Oriental groups of Segmentininae, such as Helicorbis, 
Intha, and Hippeutis, all having the peculiar embracing whorls so charac- 
teristic of Segmentina. This feature alone marks the assemblage of genera 
as of subgeneric solidarity. 

Genus PARAPLANORBIS Hanna, 1922 

Type by original designation Planorbis condoni Hanna 

1922. Paraplanorbis H.'Vnna, Univ. Oregon Pub., I, No. 12, p. 4. Type Planorbis 
(Par a planorbis) condoni Hanna. As section of Planorbis. 

1934. Paraplanorbis Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 59. Type Planorbis 

condoni Hanna. As section or subgenus of Drepanotrema. 

1935. Paraplanorbis Hexderson, Non-Marine Moll. N. Amer., p. 245. Fossil. Type 

Planorbis condoni Hanna. 

Shell (plate 81, fig. 5) . Whorls rounded on the periphery as in Heli- 
soma Swainson but aperture not expanded, umbilicus very narrow, and 
size minute (Hanna, 1922, p. 4, description of subgenus). 

Hanna's description of the species Planorbis condoni is as follows: 
'Shell ultradextral, planorboid, composed of about four and one-half regu- 
larly increasing whorls; apical cavity a cone of about 120 degrees. Last 
whorl slightly angulated about the upper margin and descending slightly 
at the aperture. Lines of growth fine and even, giving the shell a silky 
luster. Umbilicus deeply rimate 0.51 mm. in diameter. Aperture roughly 
triangular but rounded on the outer lip; not expanded or thickened but a 
dejiression both above and below the periphery. Diameter 2.67 nnn.; 
altitude 0.35 mm.' 

Geographical and Geological Distribution. Vicinity of Warner Lake, 
eastern Oregon. Hanna's locality No. 212. Pliocene period. 

Species Considered as Valid. Paraplanorbis condoni (Hanna), geno- 
type, is the only species ascribed to this originally monotypic genus. 

Remarks. This fossil genus is related to Drepanotrema and is con- 
sidered a section or subgenus of the genus by Pilsbry (1934, p. 59). While 
the wiiorls are of a clasping or embracing nature, as is usually the case in 
Drepanotrema and its allies, the spire (left side) appears entirely different, 
the depression being narrow and the whorls deeply immersed. In view of 
the difficulty in this family of placing a group in its correct position in the 
classification by the shell alone, it would seem that the interest of nomen- 
clature is best served by considering Paraplanorbis a separate genus of 
Segmentininae related to Drepanotrema. Its geographical location, also, 
so far removed from the present day distribution of Drepanotrema, is 
another reason for such procedure. 



120 The Molluscan Family Planorbidae 

Genus PLATYTAPHIUS Pilsbry, 1924 
Type by original designation Planorbis heteropleurus Pils. and Van. 

1896. Planorbis heteropleurus Pilsbry and Y.an.4tt.\, Proc. Acad. Nat. Sci. Phil., 1896, 

p. 562, plate 26, figs. 1-3. 
1924. Platytaphius Pilsbry, Proc. Acad. Nat. Sci. Phil., 76, p. 51. Type Pla7wrbis 

heteropleurus P. and V. As section of Planorbis. 
1931. Platytaphius Thiele, Handbuch, Teil 2, p. 479. Type Planorbis heteropleurus 

Pils. and Van. As section of Planorbis. 
1934. Platytaphius Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 59. Type Planorbis 

heteropleurus Pils. and Van. As section of Drcparwtrema. 

1934. Platytaphius Henderson and Rodeck, Jour. Pal., VIII, p. 268. Type Planorbis 

heteropleurus Pils. and Van. As genus. 

1935. Platytaphius Henderson, Non-Marine Moll. N. Amer., p. 254. Fossil. Cites two 

fossil species from Oregon. 

Shell (plate 79, figs. 10-12). Of medium size, ultradextral, moderately 
solid, corneous-white, rather opaque, the surface with fine, close growth 
lines; earlier whorls rather deeply and about equally sunken on the two 
sides; convex, and strongly angulate or keeled in the middle, on the right 
side; periphery conspicuously carinated on the left side, which is shallowly 
vortex-shaped, the whorls nearly flat. Last whorl slightly wider on the right 
than on the left side. Whorls three and one-half, all visible on both sides, 
the last wider than the spire. Aperture very oblique, rounded-pentagonal, 
the right margin produced forward (Pilsbry and Vanatta, 1896, p. 562). 
There are fine punctations on the embryonic whorls. 

Animal. At present unknown anatomically. 

Geographical Distribution. Lake Titicaca, Peru. 

Geological Distribution. Pliocene to Recent fauna. 

Species Considered as Valid. Platytaphius heteropleurus (Pilsbry and 
A'anatta I is the only recognized species. 

Remarks. In describing this peculiar mollusk, Pilsbry says: 'This 
remarkable species is totally unlike P. titicacensis Clessin, P. montanus 
d'Orbigny, and P. andecola d'Orbigny, species already known from this 
Andean lake. It is most like P. andecola, but much flatter with differently 
lilaced keels, and in fact, so diverse in characters that no profitable com- 
parison can be made' (1896, p. 562). In 1924 (p. 51 ) , this species was made 
the type of a section of Planorbis and in 1934 (p. 59), it was made a sec- 
tion of the genus Drepanotrema. In a paper by Henderson and Rodeck 
(1934, p. 268) , the authors state that 'it is so distinct that it might be better 
to consider it a genus.' With this statement the present author is in com- 
plete agreement for the general form of the shell is so distinct from that of 
any other species of Drepanotrema that it does stand quite alone. W^hat its 
real affinities are can not be known until its anatomy has been investigated. 
It may belong near Drepanotrema or it may belong elsewhere. 

Henderson and Rodeck ( 1934, p. 268) have associated two extinct 
molluscan species from the Pliocene of Oregon with Platytaphius. The 
localities are sixteen miles southwest of Vale, Oregon. This locality is so 
far removed from Lake Titicaca, in Peru (more than 5000 miles), that it 
would seem impossible for species of any group without intermediate habi- 
tats to become established so far apart. Yet the two species from Oregon 
correspond fairly well with the diagnosis of the genus Platytaphius. Ad- 



Subjmnilies, Genera, and Subgenera — Recent and Fossil 121 

ditional si)ecies, recent or fossil, may be found somewhere between these 
extreme points. At present there seems no alternative but to include the 
Oregon fossils in Platytaphiiis, since no diagnosis could be made that 
would include the one and exclude the other. The two species of fossils 
from Oregon are Platytaphius vialheurcnHiH and P. 7nilleri Henderson and 
Rodeck, figured on j:)late 37 of the publication cited, figs. 6, a, b, c and 
9, a, b, c. 

Genus ACRORBIS Odhner, 1937 

Type by original designation Acrorbis petricola Odhner 

1937. Acrorbis Odhner, Archiv. fiir Zoologi, Band 29B, No. 14, ]). 1. Nov. 9, 1937. 

Type Acrorbis petricola Odhner. As genus. 

1938. Acrorbis Pilsbry, Nautilus, LI, p. 107 (review). 

Shell (plate 72, figs. 1-3). Ultradextral, very small, thin, but firm, of 
circular form, with elevated spire, shell covered with a shining cuticle, 
openly umbilicatc; whorls slowly increasing, arched, high, simple; aperture 
very oblique, broadly ovate; lips simple, very thin because of the lack 
of lime in the mouth-building; shell brown, dark and reddish above, under- 
side more grayish; apex deep brown, globular, smooth, the following whorls 
with very weak spiral lines. Height of aperture same as height of whorl. 
Height 1.5 mm.; diameter 2 mm. (translated from Odhner). 

Animal (plate 72, figs. 5, 6). Gray, the upper surface of the mantle 
flecked with black. The head is darker gray and neck blackish. The foot is 
broadly o\'al with thin borders and without any furrows on the sides. The 
tentacles are narrow, when fully extended, on the end obliciuely truncated. 
The eyes are on the inner side of the base of the tentacles. The left tentacle 
differs from the right tentacle in being bifid at the end. The head is 
sharply pigmented between the eyes. 

ANATOMICAL CHARACTERISTICS 
PLATE 72 

GENITALIA. Male Organs (fig. 10). No seminal vesicle is show^n in 
the figure or mentioned in the description. The prostate is almost as long 
as the uterus and oviduct and has eight large diverticula in a single series. 
Neither description nor figure indicates the presence of a separate prostate 
duct. The vas deferens (v) is a long and narrow tube. The penial complex 
(fig. 9) is elongated, the preputium, about one-third of the entire length, 
merging into the vergic sac without marked constriction between these 
sacs. There is a wide retractor muscle (rp) which appears to be attached 
about midway of the length of the vergic sac. Above the vergic sac there is 
a wide flagellum less than half as long as the vergic sac. Internally there 
is a long, tube-like verge and a diaphragm of fleshy ridge separating the 
preputium from the vergic sac. The upper end of the flagellum is said to 
liave two cavities, one on each side of a central tube (fig. 9, a). 

Female Organs (fig. 10). The spermatheca (b) is large and globular 
and is attached to the short, narrow vagina by a very short duct about 
one-third the length of the diameter of the spermatheca. The uterus (u) is 
at first as narrow as the vagina, but swells to several times this diameter 
posteriorly where it joins the nidamental gland. The oviduct is not shown 
clearly but evidently narrows to the point of junction with the ovisperm 
duct. The albumen gland is not figured. 



122 The Molluscau Family Pknwrbidae 

Hermaphrodite Organs. The ovotcstis (go) is few-lobcd, consisting of 
but five diverticula, which are smaller than the diverticula of the prostate. 
It is not stated whether the lobes of the ovotestis are in a single or a double 
row. The ovisperm duct (od) is almost as long as the uterus and oviduct 
combined and is a very narrow tube. 

Respiratory System. The pseudobranch (figs. 5, 6, k) is shown as bifid 
at the extremity. It is a narrow projection about twice as long as wide, 
and probably bears the anal outlet as in other Planorbidae. The kidney 
(fig. 5, n) is long and narrow without a superposed ridge. 

Digestive System (fig. 8). There is a long and narrow oesophagus, an 
ovate stomach with a short pyloris and a very short blind sac (caecum, c), 
and a long intestine which makes a loop around the stomach and another 
around the liver, extending forward in the rectum (r) to the outlet near the 
pseudobranch. 

The buccal sac (fig. 7) is elongated, wide at the posterior end and much 
elongated at the anterior end. There is an unusually long radula sac (t) 
which forms a narrow tube as long as the whole radula sac. The salivary 
glands (s) are short, entering the radula sac by a fine tube. The jaw is 
said to be like that of Parapholyx iPompholycodea) . 

The radula (fig. 4) formula is not given but sixteen teeth show in one 
row in the figure which would make the formula 16-1-16. The center tooth 
has two wide cusps which do not reach the lower margin of the base of 
attachment. The laterals are sciuarish with a long, spade-shaped mesocone 
reaching the lower margin of the base of attachment, and a short entocone 
and ectocone about half as long as the mesocone. The intermediate teeth 
have the cusps more nearly equal in size. The marginals appear wide and 
low, the entocone and ectocone splitting into two smaller cusps. 

The information concerning this genus has been drawn entirely from 
the original paper and figures bv Oclhner. His figures are reproduced on 
plate 72. 

Geographical Distribution. State of Santa Catharina, Brazil. It lives 
in damp moss on rocks over which water trickles. 

Species Considered as Valid. Acrorbis; petricola Odhner, type of the 
genus, is tlie only species recognized. 

Remarks. Acroi^bis is apparently a very distinct group of South Ameri- 
can Alollusca. It is not related to Carinijex or Parapholyx {Pompholy- 
codea) as indicated by Odhner, these two genera belonging to another 
subfamily, the Helisomatinae, in which there is a penial gland in the male 
comjilex. It scarcely appears to belong with Choanomphalus. It is also com- 
pared with Neoplanorbis Pilsbry, but that group is referable to the family 
Ancylidae, not Planorbidae. 

Pilsbry has stated (1938, p. 107) that it is related to either Tropicorbis 
or Drepanotrema. The presence of a fiagellum indicates a relationship with 
Drepanotrema and the few diverticula of the prostate in a single series 
indicates the same relationship, although the diverticula are more crowded 
than has been observed in species of Drepanotrema examined. Acrorbis 
differs from Drepanotrema in the wide form of the fiagellum, the shape of 
the penial complex, wide for the whole length with no differentiation 
between preputium and vergic sac, the globular spermatheca on a very 
short duct, and the helicoid form of the shell, quite different from the 



Subfamilies, Genera, and Subgenem — -Recent and Fossil 123 

overlapping whorls of Drcpanotrona. The very long radula sac is also 
a characteristic feature of the anatomy. 

The radula appears very different from that of Drepanotrema (see 
plate 68) because of the apparent absence of interstitial cusps between the 
larger cusps. These might have been present but overlooked because of 
tiic small size of the radula teeth. The general shape of the mesocone in 
Odhncr's figure (4) is suggestive of the same cusp in Drepanotrema, but 
the ectocone and entocone are much shorter. The radula is markedly dif- 
ferent from that of Tropicorbis. 

Aa^orbis, therefore, appears to be another one of the peculiar groups 
of South American Planorbidae, related to Drepanotrema, but distinct 
by both shell and anatomy. 

Subfamily HELISOMATINAE F. C. Baker, 1928 

Prostate diverticula compound or multiple, consisting of a basal stem 
with branches grouping around a short prostate duct which is in intimate 
contact with the sperm duct. In cross section, the prostate exhibits a fan- 
like design. A penial gland is nearly always present with an external duct 
of greater or lesser length. The kidney is usually heavily ridged. The jaws 
are sim})le, of three pieces, a superior and two lateral jaws. 

Type genus Helisoma Swainson. 

The groups referred to this subfamily are noted below. 

With one penial retractor muscle: Helisoma and subgenera Seminolina, Picr- 
osoma and Planorbella. 

With two penial retractor muscles: Carinifex and Parapholyx. 

Without penial gland duct: Planorbarius. 

The fossil groups Vorticifex, Perrinilla, and Pompholopsis are included 
in this subfamily because of likeness of shell to Carinijex or Parapholyx. 

With the exception of Planorbarius, which appears to have character- 
istics admitting it to this group, the subfamily is wholly American and 
is perhaps the most important planorbid element in the North American 
molluscan fauna. It is widespread throughout the northern part of North 
America and the species are numerous. 

Genus HELISO:VIA Swainson, 1840 

Type by original designation Planorbis bicarinatus Sowerby (= Planorbis 
bicarinatits Say = Planorbis anceps Menke) 

1840. Helisoma Sw.\ixsoN, Treat. Malac, p. 337. Type Planorbis bicarinatus Sowb. 

As subgenus. 
1846. Helisoma Herrm.^nnsen, Ind. Gen. Mai. Prim., I, p. 516. Tj^pe Planorbis 

bicarinatus Say. As subgenus. 
1865. Helisoma Binney, L. and FW. Sh. X. A., II, p. 112. No type cited. As subgenus. 
1870. Helisoma Dall, Ann. N. Y. Lye. N. H., IX, p. 351. Type Planorbis bicari- 
natus Sowb. As subgenus of Planorbis. 
1872. Helisoma Tryon, Mon. FW. Univ. Moll. U. S., pp. 188, 198. No type cited. As 

subgenus. 
1880. Helisoma Fischer and Crosse, Moll. Terr. Fluv. Mexico et Guat., II, p. 60. As 

subgenus. 
1884. Helisoma Tryon, S. and S. Conch., Ill, p. 106. Type Planorbis bicarinatus Say. 

As subgenus. 
1886. Helisoma Cle.ssix, Syst. Conch., XVII. i). 33. Tyjie Pl((uurbi.'< bicarinatus S:iy. 

As subgenus. 



124 The Molluscan Family Planorhidae 

1899. HeUsoma Martens, Biol. Cent. Amer., Moll., p. 381. No type cited but includes 

Pierosoma. As subgenus. 
1902. HeUsoma F. C. Baker, Moll. Chi. Area, II, p. 287. No type cited. As subgenus. 
1905. HeUsoma Dall, Alaska Moll., pp. 81, 84. Type Planorbis bicarinatus Sowb. 

As subgenus. 
1912. HeUsoma Hannibal, Proc. Mai. Soc. London, X, p. 157. Type Planorbis 

antrosus Conrad. As genus. 
1918. HeUsoma Walker, Miscel. Pub., Mus. Zool., Univ. Mich., No. 6, p. 11. Type 

Plaiiorbis bicarinatus Say. As subgenus. 
1921. HeUsoma Germain, Rec. Ind. Mus., XXI, pp. 6, 64. Type Planorbis carinatus 

Say. As subgenus. 

1923. HeUsoma Wenz, Fossil. Cat., Pars 22, p. 1522. Genotype HeUsoma bicarinata 
(Sowb.). As genus. 

1926. HeUsoma F. C. Baker. Trans. Wis. Acad. Arts and Sci., XXII, p. 201. Type 
Planorbi^s bicarinatus Sowb. As genus. 

1928. HeUsoma F. C. Baker, Fresh-water Moll. Wis., I, p. 311. Type Planorbis 

bicarinatus Sowb. As genus. 

1929. HeUsoma Chamberlin and Jones, Bull. Univ. Utah, Biol. Ser., No. 1, p. 145. 

Genotype Planorbis bicarinatus Sowb. As genus. 

1930. HeUsoma H. B. Baker, Occ. Papers, Mus. Zool., Univ. Mich., No. 210, p. 43. 

Planorbis bicarinatus Say. As genus. 

1931. HeUsoma F. C. Baker, Proc. Zool. Soc. London, p. 584. Type Planorbis bi- 

carinatus Sowb. As genus. 

1931. HeUsoma Thiele, Handbuch, Teil 2, p. 479. Type Planorbis bicarinatus Say. 
As section of Planorbis. 

1934. HeUsoma Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 47. Type Planorbis bica- 
rinatus Say. As genus. 

Subgenus HELISOMA SS. 
Type Planorbis anceps Menke 

Shell (plate 80, figs. 1-6). Large, sinistral, of comparatively few 
whorls which rapidly increase in size, carinated; spire and umbilicus 
funicular; aperture expanded, outer lip thickened. 

Animal. Yellowish or brownish, flecked with whitish; there are s]5ots 
of color near the eyes and between the tentacles, and the mantle is spotted 
with dark mottling, especially over the kidney. The tentacles are long and 
filiform and the velar area is notably developed. The shell is carried almost 
perpendicularlv. 

ANATOMICAL CHARACTERISTICS 

PLATE 23. HeUsoma anceps (Menke) 

GENITALIA. Male Organs (fig. 11). Seminal vesicle (SV) short (about 
1 mm. long) and widely rounded, composed of many small follicles. An- 
terior to the seminal vesicle, for the space of 2.5 mm., the ovisperm duct 
is bordered by many small follicles which may represent a portion of the 
seminal vesicle (SO). The sperm duct (SPD) is about 6 mm. long and is 
of wide diameter, somewhat sausage-shaped, the tube about 0.3 mm. in 
diametei'. The prostate (PRS) is ovate in shape, about 2.5 mm. long, 1 mm. 
wide and less than 1 mm. in height. It is composed of numerous diver- 
ticula forming a pavement-like pattern when viewed externally. In section 
(fig. 9) the prostate is fan-shaped, composed of six to eight diverticula 
each of which is branched two to four times toward the distal end. The 
prostate is placed on a short prostate duct which unites with the sperm 
duct to form the vas deferens (plate 22, fig. 12) . The vas deferens (VD) 



Subfamilies, Genera, and Subgenera — Recent and Fossil 125 

is about 14 mm. long, somewhat smaller in diameter than the sperm duct. 
It is still further diminished in diameter as it emerges from the muscular 
tissue to enter the jienial complex (plate 23, fig. 3, VD). Near the summit 
of the vergic sac the vas deferens enlarges to form an epiphallus (EPI). 

Tlic penial comjilex (plate 23, fig. 3) is a short, somewhat pyriform 
organ about 4 mm. long. The preputium (PR) is very wide (1.7 mm.) and 
about 2.5 mm. long. The vergic sac (VS) is somewhat bullet-shaped, 1.5 
mm. long and 1 mm. wide. There is no marked constriction between the 
preputium and the vergic sac. There is a wide retractor muscle (RM) 
attached to the preputium just above the male opening. On the right side 
of the preputium there is a group of supporting muscles (S^I). This group 
may form a wide, solid band or it may be broken up into ten or twehT 
smaller muscular bands. The supporting muscles are attached to the roof of 
the mantle cavity. There is a short (2 mm. long), narrow, external tube or 
duct (DC) on the outside of the preputium and adherent thereto. This 
penial duct tapers to half its diameter as it enters the junction of the 
prejiutium with the vergic sac. 

Internally (fig. 2) the penial comjilcx shows two cavities, an upper 
vergic space and a lower preputial space, separated by a muscular ring 
or diaphragm (D) which is capable of great contraction and expansion 
(see fig. 5). In the preputial space there is one large, vertical fold or pi- 
laster (PL) and several smaller vertical ridges. Attached to the wall of the 
preputium at the upper end of the large pilaster is a rounded, cup-shaped 
penial gland (GL). In section (fig. 1) this gland is seen to have the cup- 
shaped, bulbous termination divided into two parts, an upper portion with 
smooth or only slightly developed vertical fokls (OC) and a lower portion 
(LC) lined with heavy vertical folds (GF). The floor of this cup is covered 
with pavement-like folds, from which a narrow duct (DC) extends through 
the neck of the gland and emerges through the bodv wall of the preputium 
and becomes the external penial duct. A section through the region at the 
junction of the two spaces (fig. 6) shows the relationship of the muscular 
ring or diaphragm (D) to the gland duct, the latter penetrating the thick 
wall of the lower portion of the vergic sac and opening into this cavity just 
above the diaphragm. In fig. 11, plate 22, the outer cup of the gland is 
turned back to expose more fully the folds of the inner cuji (Helisoma 
an reps percarinatian) . 

Tlie A'orgc (plate 23, fig. 2, V) is normally short and wide and tapers 
abruiitlv to a narrow point. In fig. 1 on plate 22 {Helisoma anceps latch- 
fordi) it is shown well-extended, exhibiting an elongated, cylindrical form, 
the supporting muscles (MS) plainly indicated at the upper end near the 
top of the vergic sac. The enlarged epiphallus is also indicated. At the 
terminal end of the verge the seminal opening is placed in the center of the 
organ with a small, sharp appendage or papilla extending slightly below 
the end of the verge. In fig. 10 on plate 22, the end of the verge is shown 
with this feature enlarged to show the pointed pajiilla and the centrally 
located seminal opening. 

The penial complex may assume a number of shapes, depending uj^on 
the sexual condition of the animal. Often it is seen as shown in fig. 8, 
plate 23, the penial gland pushed upward causing the com]ilex to assume 
a bilobed aspect. The penial gland and the verge may sometimes be seen 
l^rotruding from the male ojiening and lying on the neck of the animal. 



126 The Molluscan Family Planorhidae 

The verge is often extended into the preputial cavity as shown in figs. 2, 3, 
and 4 on pLate 22. 

Female Organs (plate 23, fig. 11). The spermatheca (S) and its duct 
are 5 mm. long, the spermatheca elongated, sausage-shaped and slightly 
less in length than the duct, which is rather wide and enlarged as it enters 
the long (1.5 mm.) and narrow vagina. The uterus (U) is about 5 mm. 
long, widening upward to the nidamental gland (NG), which is about 
2 mm. long and 1 mm. wide. The oviduct (OD) is about 4 mm. long and 
0.3 mm. in diameter. There is a large carrefour (CD into which the small, 
narrow duct of the albumen gland enters (DA). The albumen gland (fig. 7) 
is squarish in form, about 2.5 mm. in diameter and is composed of small 
follicles. Near the albumen duct the lobules are much larger than in the 
body of the gland. A depression crosses the gland on the under side mark- 
ing the space occupied by the intestine. 

Hermaphrodite Organs (fig. 11). The ovotestis (OT) consists of 
many rows of club-shaped diverticula having a pavement-like appearance 
from the surface of the gland. In section (fig. 10), the ovotestis is seen to 
be composed of about a dozen diverticula extending fan- wise from the 
ovisperm duct. The free portion of the ovisperm duct (SO) is somewhat 
shorter, between the seminal vesicle and the ovotestis, than between the 
seminal vesicle and the oviduct, but about 1 mm. in both regions. The larger 
portion of the ovisperm duct is occupied by the seminal vesicle. 

The genitalia of the races of Helisoma anceps, as far as they have been 
examined, are remarkably uniform. In specimens of Helisoma anceps 
percarinatum from Douglas Lake, Michigan, there was some variation in 
the form of the retractor muscle, this being often divided into several 
branches toward the columella muscle (plate 22, figs. 2, 3, 4). In one 
specimen (fig. 4) there were two muscles, an abnormal condition. 

Respiratory and Renal Systems. The pseudobranch (plate 23, fig. 4, P) 
is squarish in shape, rounded below, pad-like, with a distinct ridge passing 
down the center from the rectal region. The pseudobranch is 2 mm. wide 
and about 1 mm. high. The rectum is very wide and there is an irregular 
crest or ridge extending down the center (R). This ridge extends backward 
on the rectum about a cjuarter of a whorl. It narrows notably as it nears 
the anal end of the rectum. The pneumostome (PS) is not notably large. 

The kidney (plate 44, fig. 1) is 7 mm. long and 2 mm. wide at the 
upper (pericardial) part, tapering to about 1 mm. wide at the lower part. 
The ureter is less than 1 mm. long and is sharply reflexed parallel to the 
long axis of the kidney. The pericardium is nearly 2 mm. long and 1 mm. 
wide. There is a large and conspicuous superposed ridge extending from 
just below the pericardium to the urethral portion of the kidney and going 
beyond the kidney almost to the mantle margin. 

In cross section (fig. 7), this ridge, at the i)oint in fig. 1 marked by 
the arrow, is seen to form a long fold which extends over the kidney 
causing it to appear rounded in a ventral view of the kidney, as shown 
in fig. 1. The lumen is regularly rounded and the two blood vessels appear 
on each side at the lower part of the section. A small ridge to the left of the 
lumen is shown in the figure. This ridge in the mantle is present in all 
species of the family. 

A cross section of the kidney of Helisoma anceps latchfordi (fig. 8), 
taken at about the middle of the kidnev, shows a less extensive ridge (RK) 



Subfamilies, Genera, and Subgenera — Recent and Fossil 127 

but is otherwise similar to typical anceps. The form of the section may 
vary when taken from different parts of the kidney, as is shown in several 
sj^ecies of Helisoina. 

Digestive System. The stomach is bulbous and tapers into the pyloris. 
The intestine loops around the stomach, passes over the oesophagus, turns 
backward in a long loop around the liver and then runs forward to the 
l^seudobranch in the form of the rectum. The general form is like that of 
HeUsomn trivolvis shown in fig. 1 on plate 48. 

The buccal sac is short-ovate. The salivary glands are narrow and 
about twice as long as the buccal sac. They are joined behind. 

The jaw (plate 49, fig. 1). There is one wide, low, arched superior jaw 
(about 1 mm. wide) and two narrow, ribbon-like lateral jaws somewhat 
longer than the superior jaw. The superior jaw is finely striated on its 
anterior face. 

The radula has the variable formula 22-1-22 to 30-1-30, with 150 to 193 
rows of teeth. A radula from specimens from Maple River, Michigan, is 
figured on plate 53, fig. 1. The center tooth is squarish with two short, 
wide cusps. The lateral teeth (1-5) have a squarish reflection which ex- 
tends well below the lower margin of the base of attachment. The cusps 
are spade-shaped, the mesocone the longest and the ectocone the shortest. 
The ectocone of the fourth tooth is split into four small cusps. The inter- 
mediate teeth (6-7) are narrower than the lateral teeth, the base of at- 
tachment very short. The entocone is broken up into two or three small 
cusps and several small cusps appear on the outer edge of the tooth above 
the ectocone. The marginal teeth (8-14) are much narrower, this feature 
increasing toward the outer margin of the membrane where the teeth are 
^'ery long and narrow (14). In the marginal teeth the entocone is broken 
up into fine serrations numbering from five to ten cusps, the number in- 
creasing in the outer teeth (compare 8 and 14). The mesocone becomes 
somewhat smaller but is not modified. The ectocone is distinct in the 8th 
tooth with three small cusps above it. From the 10th tooth this area 
changes to small serrations five to six in number. The outer marginal teeth 
appear like a saw, wdth one large tooth (the mesocone) in the center 
(see 14). The extreme outer marginals are vestigial. 

The radulae of anceps and its races vary considerably, principally in 
the numerical formulae, but also in the number and position of the cusps. 
The table below indicates the extent of this variation. The columns are 
all as follows, reading from left to right: Locality, formula, lateral teeth, 
intermediate teeth, plate, and figure. 
Helisoma anceps (Menke). 

Maple River, Michigan 23-1-23 to 24-1-24 1-5 6-7 Plate 53, fig. 1 

I'nionville, Conneotiout 23-1-23 to 25-1-25 1-5 6-7 Plate 53, fig. 3 

ChautaiKiua Lake, New York 22-1-22 to 25-1-25 1-7 8-9 Plate 53, fig. 2 

Moo^ie Ear Creek, Wisconsin 26-1-26 to 27-1-27 1-6 7-9 

Cleveland, Oneida L., New York 25-1-25 to 27-1-27 1-6 7-S 

There are 150 to 160 rows of teeth. 
HcUsoinn anceps sayi F. C. Baker. 

Bayfield, Wisconsin 27-1-27 to 27-1-27 1-5 6-7 Plate 53, fig. 4 

Helisonta anceps percarinatuni (Walker). 

Douglas Lake, Michigan 27-1-27 to 30-1-30 1-8 9-10 Plate 54, fig. 1 

There are 193 rows of teeth. 



128 The MoUuscan Family Planorbidae 

Helisoma anccps royalense (Walker). 

Bamiji Lake, Ontario 25-1-25 to 27-1-27 1-S 9 Plate 54, fig. 2 

There are 170 rows of teeth. 
Helisoma anceps cahni F. C. Baker. 
Big Muskallonge Lake, Ontario 27-1-27 to 27-1-27 1-6 7-9 Plate 54, fig. 3 

There are 160 rows of teeth. 
Helisoma anceps latchfordi (Pilsbry). 
Meach Lake, Quebec 27-1-27 to 30-1-30 1-6 7-9 Plate 54, fig. 4 

There are 190 rows of teeth. 

For the above data more than forty siiecimens have been examined. In 
general form of teetli, there is complete agreement in all radulac examined, 
both from the same locality and from different places. The formulae vary 
and along with this variation, the numbers of lateral and intermediate 
teeth likewise vary. 

Abnormal teeth arc connnon in radulae of Heluoma anceps. In a speci- 
men from Maple River, Michigan, the fourth lateral of the fifteenth row 
had the ectocone broken up into four small cusps (plate 53, fig. 1). In a 
specimen from Chautauqua Lake, New York, the center tooth of the 118th 
row was broken up into three small cusps and one large cusp. In the first 
lateral of the same row, the entocone was split into two small cusps 
(plate 53, fig. 2). In a specimen from Unionville, Connecticut, the fifth 
lateral of the ninetieth row had a split ectocone. The 8th and 9th teeth of 
this row had the intermediate in unusual form. This row shows the shape 
of the teeth on the left side of the membrane (plate 53, fig. 3, lower row). 

In the races of anceps, the same tendency to form abnormal teeth is 
observed. A specimen of saiji from Bayfield, Wisconsin, had the center 
tooth of the seventy-fifth row with three small cusps on the left side and 
one small cusp on the right side of a central cusp. All of the laterals in 
this row had the entocone broken up into two small cusps (plate 53, fig. 4, 
lower right row). In a radula of percarinahmi from Douglas Lake, Michi- 
gan, the first and second laterals of the 100th row had the entocone split 
into two smaller cusps (plate 54, fig. 1, lower row). A specimen of latch- 
fordi, in the sixtieth row, had the central tooth with an extra cusp on each 
side of two smaller central cusps (plate 54, fig. 4, 60). All of the teeth of 
this race examined had two very small denticulations on the edge of the 
reflection above the ectocones (plate 54, fig. 4). 

Geographical Distribution. The species of typical Helisoma inhabit 
North America from British America (Hudsons Bay) southward to Lou- 
isiana and Alabama and westward to the Rocky INIountains. 

Species Considered as Valid. This, the typical subgenus of the genus 
Helisoma, contains one sj^ecies with many races and a second species with 
two recognizable races. 

Helisoma anceps anceps (Menke) 1830 Helisoma anceps unicarinatum (Halde- 
(=^ Planorhis bicarinatus Say 1819 man) 

(preoccupied), P. antrosus Conrad, Helisoma anccps striatum (F. C. Baker) 

1834) Helisoma anceps cahni F. C. Baker 

Helisoma anceps sayi F. C. Baker Helisoma anceps latchfordi (Pilsbry) 

Helisoma anceps shellense F. C. Baker Helisoma anceps portagensis (F. C. 
Helisoma anceps percarinatum (Walker) Baker) 

Helisom.a anceps royalense (Walker) Helisoma anceps aroostookense (Pilsbry) 

Helisoma anceps ruski F. C. Baker Helisoma eucosmium (Bartsch) 

Helisoma anceps jordanense (Winslow) Helisoma eucosmium vaughani (Bartsch) 



Subfa/nilies, Genera, and Subgenera — Recent and Fossil 129 

Geological Distribution. Miocene?, Pliocene to Recent fauna. 

Remarks. Typical Hclisotua is characterized by a short and wide, some- 
what bulbous penial complex without a notable constriction between the 
preputium and the vergic sac. There is a cup-shaped penial gland with 
a short, narrow, almost straight penial gland duct. The prostate and ovo- 
testis are made up of many small diverticula radiating from a duct in fan- 
like i)attern when seen in cross section. Helisoma differs from Pierosoma 
in its shorter penial gland duct, wider and shorter vergic sac, and generally- 
different penial complex. From Seminolina, which resembles Helisoma in its 
short i)enial gland duct, it differs by its shorter duct. The radular teeth 
also differ from Seminolina in having the cusps sharply aculeate instead 
of rounded. The' shell of Helisoma is also quite different from Pierosoma 
and Seminolina in its general bicarinate form with the spire and umbilicus 
both deeply concave. 

As a subgeneric name, Helisoma has been known in molluscan litera- 
ture for many years. Binney (1865, p. 112), Tryon (1870, p. 188), and 
Dall (1905, p. 81) cite the name, using, however, onlv characteristics of 
the shell for its distinction. In 1926 (p. 201) and in 1928 (I, p. 311), Baker 
elevated the group to generic rank, basing the distinction on the peculiar 
genital complex of the male organ. In 1931 (p. 584), the genus was diag- 
nosed by Baker and the distinctions of the genitalia described and figured. 

Authors generally have misquoted the type of the genus. The Planorbis 
bicarinatiis of Sowerby, while with little doubt the same as Planorbis bi- 
carinatus Say, has nothing to do with Say's species and Sowerby was 
probably not aware that there was another bicarinatus. Dall (1905, p. 84) 
cited the type as Planorbis bicarinatus (Say) Sowerby, which is incorrect, 
although the type is correctly cited on page 81. The citation of Planorbis 
bicarinatus Say, as has been made by some authors, is also incorrect. Say's 
species dates from 1817, Sowerby 's from 1824. 

A careful study of Sowerby's description and his two figures on plate 
clxxvii (fig. 4) leaves little doubt about the unity of his species with that 
of Say. Binney (1865, p. 124) thought it might be Planorbis campanulatus 
Say, but both figures and description point to bicarinatus. Binney based 
his opinion evidently on the lower fig. 4 of the plate, which is not clear, 
and might be mistaken for cam'panulatus. There is little question about 
the upper figure being intended for bicarinatus. Unfortunately this appro- 
priate name can not be used, as it is preoccupied for a Paris Basin fossil. 
Conrad's Planorbis antrosus 1834 has been used in place of bicarinatus, 
but ]\Ienke's name precedes this by four years and must be accepted. 

Regarding the name Helisoma, it is a Greek noun in the neuter gender 
and all specific names must, of course, also be neuter (H. B. Baker, 1930, 
p. 139). 

Subgenus SEAIINOLINA Pilsbry, 1934 

Type by original designation Helisoma scalare (JajO 

1870. Amcria Dall, Ann. N. Y. Lye. X. H., IX, ]>. 356. Example Phym scalaris Jay 
(non H. and A. Adams, 1855). 

1886. Thomsnnia Axcey, Le Xaturali.><te, Mil, p. 358; not of Signoret, 1879 (He- 
rn ipt era). 

1931. Thnmsonia Thiele, Handbiich, Teil 2, p. 479. Type Planorbis scalaris (Jay). 
As section of Planorbis. 

1934. Seminolina Pilsbry, Proc. Acad. X^at. Sci. Phil.. 86, p. 31. Type Helisoma 
scalare (Jay). Anatom3^ As subgenus of Helisoma. 



130 The Molluscan Family Planorbidae 

Shell (plate 80, figs. 7-12). Large, sinistral, physa-shaped or planorboid, 
with every gradation between these forms, usually widely or deeply um- 
bilicated; surface smooth, usually glossy, without the thread-like striae of 
Pierosoma. 

Animal (plate 70, fig. 3 (adult), fig. 2 (young) ). With large velar area 
and long tentacles as in Helisoma. Color variable. In scalare olivaceous, in 
duryi and varieties dark olivaceous in old specimens, purplish on top of 
head, fiecked with white. Bottom of foot dark horn or purplish, fiecked 
with fine light dots. Tentacles lead color. Mantle yellowish or grayish over 
lung and kidney, with few black or brown spots. Immature specimens are 
more yellowish with few or no dots. The young animal is hyaline and 
transparent, the internal organs yellowish or pinkish. 

ANATOMICAL CHARACTERISTICS 
PLATE 28 

GENITALIA. Male Organs (fig. 14). Seminal vesicle (SV) about 2.5 
mm. long, varying in width, but 1 mm. wide at the center and about 
0.5 mm. wide anteriorly and posteriorly of this area. The seminal vesicle 
is composed of many small glands. The ovisperm duct bears many 
small vesicles along its side for over 1 mm. below the seminal vesicle. 
Sperm duct nearly 3 mm. in length, of large diameter. Prostate (PRS) ob- 
long, over 2 mm. in length composed of many diverticula arranged in fan- 
like rows. A section of the prostate near the middle shows sixteen rows of 
club-shaped diverticula (fig. 12). The prostate diverticula discharge into 
a separate duct, the prostate duct, with which the sperm duct connects 
posteriorly and the vas deferens anteriorly (see fig. 14). The vas deferens 
(VD) is about 10 mm. long, and is about half the diameter of the sperm 
duct. It is slightly enlarged (epiphallus) as it enters the vergic sac. 

The i^enial complex (fig. 10) is about 3.5 mm. long. The lower sac or 
prei)utium (PR) is pyriform, 1.3 mm. wide at the upper part and less than 
0.5 mm. wide at the male opening. There is one large retractor muscle 
(RM) which is split into four branches at the preputium and in some 
specimens (fig. 9) there may be one wide muscle of three branches with a 
narrow, separate muscle below. The muscles are attached to the upper part 
of the preputium. The supporting muscles (SM) usually form a wide band, 
split into three branches at the upper part of the preputium. In one speci- 
men there were five narrow, separate supporting muscles, each with two 
branches, all placed near the lower end of the preputium (fig. 9). 

The duct of the penial gland (DC) is rather short (3.5 mm. long) and 
tapers in diameter toward the end entering the vergic sac (fig. 6). The 
vergic sac is of about the same length as the preputium, ovate-pyriform 
in shape, about 1 mm. wide near the upper part of the sac. In some speci- 
mens examined (fig. 9) , the preputium was pushed upward and the vergic 
sac appeared as though attached to the lower part of the preputium. In 
this condition, the penial gland duct extends from the top of the preputium 
and enters the vergic sac below the level of the duct's exit. This condition 
is observed in specimens in breeding stage. 

Internally (fig. 11), the preputial sac contains several (four or more) 
narrow, slight, vertical ridges or pilasters (PL). The cavity of the pre- 
putium is partly filled by an elongate-ovate (irregularly paralleliform) 
penial gland attached by a short neck of less diameter to the body wall 



Subfamilies, Genera, and Subgenera — Recent and Fossil 131 

of the prepiitium through which the penial ckict extents (GL, DG). In 
section (fig. 7), this gLand is seen to be composed of two cup-like cavities, 
one, the inner cup, has several large glandular folds (GF) and the other, 
the outer cup, has several smaller folds attached to the wall of the cup 
(OC). The larger folds extend transversely across the cavity as shown in 
fig. 11, GL. The small cup is at the extreme end or tip of the gland. The 
gland duct enters the smaller cavity, as shown in fig. 7, DC. There is a 
narrow ridge or diaphragm which separates the vergic sac space from the 
preputial cavity. The gland duct enters the vergic space above this dia- 
l^hragm as shown in fig. 11. The verge (V) is pyriform or reversed conic 
0.9 mm. wide at the upper part and tapering to a point. The sperm canal 
has a central outlet. 

Female Organs (plate 28, fig. 14). The spermatheca (S) is bulbous, 
wide and about 1 mm. long. Its duct (SPD) is 2 mm. long, rather wide and 
increases notably in diameter at the lower end where it enters the short 
( 1 mm. long I vagina. The vagina narrows to about half its diameter at 
the female opening (VG). The uterus (U) is about 3 mm. long and is as 
wide as the diameter of the spermatheca. The nidamental gland (NG) is 
short (about 1 mm. long) and sac-like. The oviduct (OD) is about as long 
as the uterus, very wide, and bears the nidamental gland about midway of 
its length. The albumen gland (AL) is somewhat longer than wide and is 
composed of many small, gland-like vesicles (fig. 14, AL) . 

Hermaphrodite Organs. The ovotestis occupies the first and a part of 
the second whorls and is composed of ten or more rows of club-shaped 
diverticula of unequal length (fig. 13, plate 28). The free portion of the 
ovisperm duct is very short (about 0.7 mm.) both anterior and posterior 
of the seminal vesicle. 

The genitalia of Helisoma scalare examined agree perfectly with the 
figures published by Pilsbry (1934, fig. 1, b, c, d). The peculiarities are 
the wide and pyriform penial complex, the short gland duct, the elongated, 
two-cupped penial gland and the lai'ge, sacculated seminal vesicle. 

The several varieties under the name of Helisoma duryi (Wetherby) 
show some differences from scalare in their anatomy (plate 33). In 
Helisoma duryi normale Pilsbry, the genitalia are much elongated, due to 
the more widely-coiled shell (fig. 15). The seminal vesicle (SV) is much 
shorter in comparison (2 mm. long) and the gland sacs are larger. The 
sperm duct (SPD) is a long and narrow tube (7.5 mm. long). The prostate 
(PRS) is more elongated (5.5 mm. long) and contains a greater number 
of diverticula. The prostate duct is longer and the space between the 
entrance of the sperm duct and of the vas deferens is several times wider. 
The vas deferens (VD) is a long and narrow tube (over 20 mm. long). 
The spermatheca (S) is much longer and larger (3.5 mm. long) and is 
more elongate-ovate in shape. Its duct is longer (5.5 mm.) and much 
narrower. The uterus and nidamental gland are longer and narrower and 
the oviduct (OD) is narrow and much elongated. The free portion of the 
ovisperm duct is also longer. The albumen gland (AL) is more irregular 
in shape. 

The penial complex is usually short and wide but varies somewhat in 
this respect (see figs. 8. 9. 12. 17. 18). Normally (figs. 17, 18), the preputial 
sac is as long as, or only a trifle longer than, the vergic sac, and is always 



132 The Molluscan Family Planorbidae 

wide. The penial gland duct is short, as in scalare. There is usually more 
of a constriction between the preputium and the vcrgic sac than in scalare. 
Figure 8 shows an abnormal form of penial complex and fig. 12 shows 
another in which the part of the preputial sac containing the i)enial gland 
has been pushed upward. In fig. 9, this feature is still further emphasized. 

In Helisoma duriji (Wetherby), the preputial sac has been pushed up- 
ward as in normale. In Heliso))ia duryi eudiscus Pilsbry, there is consider- 
able variation. In fig. 1, the gland duct is swollen in a bilobed form, while 
in fig. 2 it is very narrow. In fig. 7, the penial complex is very wide. Figure 
5 shows the penial gland pushed upward in the lu-eputial sac. Figure 6 
shows the wider penial complex in an immature specimen with a shell 6.5 
mm. in diameter. In two specimens examined, the penial gland was ex- 
tended from the male ojiening and lay outside on the neck of the animal 
(fig. 13, duryi; fig. 16, H. d. normale). In fig. 16, it is shown just below the 
female opening. 

The penial gland in the duryi complex is of about the same shape as 
that organ in scalare. In H. d. eudiscus, the external form is shown in 
fig. 4 and a section in fig. 3. There is the same division into an inner 
and an outer cup as in scalare. In H. d. nortnale (fig. 10), a longitudinal 
section shows the same features. In Helisoma duryi, the jienial gland is 
short and wide. The gland of a half-grown specimen is siiown in fig. 19. 

The figures of the duryi complex agree with those by Pilsbry ( 1934, 
p. 34, fig. 1, f, g, h, i, j, k). As Pilsbry remarks on page 36, the anatomical 
differences are sufficient to separate scalare from duryi and its races. 

Respiratory and Renal Systems. The pseudohranch (plate 28, fig. 8) 
is shoi't and wide (Pi. There- is a hirge cremilated ridge on the rectum iR) 
which runs out on the jiseudobranch in a curve, to the right of the anal 
opening (A). The pseudobranch is 1.5 nnu. long and about 1 nun. high. 
It is contractile and its size varies greatly in preserved specimens. There 
is a large pneumostome. 

The kidney (i)late 44, fig. 4) of .^c(dare is rather short (4 mm. long), 
wider at the upper part near the ])cricardium (1 nnn. wide). The ureter is 
directetl diagonally backward. The pericardium is al)out 1 mm. long. 
A cross section of the kidney near the middle (fig. 25) shows a rather 
long, narrow crest or ridge, a small ovate lumen and two small veins placed 
just below the middle of the lumen. The small ridge in the mantle is shown 
to the left in both figures. 

In H. d. normale (fig. 5), the kidney is longer (17 mm. long) and 
comparatively narrower (3 mm.) than in scalare. The ureter is about 2 mm. 
long and is bent backward against the lower part of the kidney. A cross 
section of the kidney near the middle (fig. 26) shows it to be more com- 
pressed than that of scalare, the crest or ridge bent more to the left but 
of about the same form. The lumen is more elongated and about two and 
one-half times as wide as high. The two veins are placed near the lower 
border of the lumen. The kidney of Seminolina is more depressed than in 
Helisoma and the lumen is comparatively larger. 

Digestive System, The stomach and intestine are as in Helisoma, as 
are also the buccal sac and salivary glands. 

Jaw (plate 49, fig. 4, scalare; fig. 14, H. duryi normale) as in Helisoma, 
the superior jaw with vertical striations on the inner face. 



Subfamilies, Genera, and Suhgeiiera — Recent and Fossil 133 

Radula (plate 64). In scalare, the center tooth (figs. 1, 89) is ahiiost 
twice as wide at the base as at the summit of the reflection, the two broadly 
aculeate cusps of which reach the lower margin of the base of attachment. 
The lateral teeth (1-8) are about as broad as high and the reflection, 
which is tricuspid, extends below the base of attachment. The mesocone is 
roundly blunt, the entocone and ectocone broadly aculeate. The inter- 
mediate teeth (9-11) have the mesocone as in the lateral teeth, but nar- 
rower, the entocone as in the laterals. On the eleventh tooth, the entocone 
is split into two short, aculeate cusps. The ectocone in all intermediate 
teeth is split into two sharp cusps. The marginal teeth (12-21) are very 
long and narrow and claw-like. The mesocone is aculeate in all teeth but 
is always distinct. The entocone becomes very wide and is split into from 
four to seven small cusps. The ectoconic region on the outer margin of the 
tooth bears three very small cusps. 

In another specimen from the same locality, the teeth are somewhat 
smaller (fig. 2). In H. duryi normale, from the Tamiami Trail (fig. 3), the 
teeth are all narrower than those of scalare, although the shell is much 
larger. The two cusps of the center tooth do not reach the lower margin 
of the base of attachment. The laterals (1-11) and the intermediate 
tooth (12) are narrow but the cuspidation is the same as in scalare. The 
marginal teeth (13-29) are similar to those of scalare differing only in 
being somewhat narrower. In a specimen from Paines Prairie (fig. 4), the 
teeth are more like those of scalare. Two rows are figured, the 55th and 
the 140th. The number of intermediate teeth is smaller in normale than in 
scalare. The figures on plate 64 agree with those published bv Pilsbrv 
(1934, p. 34, fig. la). 

The formula for scalare is 27-1-27 to 29-1-29 and there are 160 to 190 
rows of teeth. Pilsbry gives 33-1-33 as the formula ( 1934, p. 35) . A number 
of membranes were examined but none gave the larger formula. The outer 
teeth are small and vestigial. 

The formula of normale from the Tamiami Trail is 28-1-28 to 31-1-31 
with 175 rows of teeth. In specimens from High Springs several radulae 
gave 27-1-27 as the formula. These specimens vary toward the race inter- 
calare. From Paines Prairie, several membranes gave 28-1-28 and 29-1-29 
with 165 rows of teeth. H. d. eudiscus from Silver Springs gave a formula 
of 27-1-27 to 28-1-28 with 154 rows of teeth. The variation in formulae is 
from 27-1-27 to 31-1-31 for the complex of duryi and to 33-1-33 for 
scalare as examined by Pilsbry. 

For the anatomical data herein presented thirty-five specimens have 
been examined from the following localities, all in Florida: 

Helisoma scalare 

Lake Butler. Collected by Dr. E. A. Andrews of the Johns Hopkins University 
Helisoma duryi normale 

Tamiami Trail, 40 miles west of Miami. Collected by Paul P. McGinty, Boynton, 

Florida 
Canal west of Boynton, Palm Beach County. Collected by Paul P. McGinty, 

Boynton, Florida 
Bridge No. 32, on canal west of Miami. Collected by W. F. Shay, St. Louis, 

Missouri 
Paines Prairie, near Gainsville. Collected by T. van Hyning, Florida State 

Museum 
Santa Fe River, High Springs. Collected by T. van Hyning 



134 The Molluscan Family Planorbidae 

H . duryi intercalare 

Canal west of Boynton. Collected by W. F. Shay 

Santa Fe River, High Springs. Collected by T. van Hyning 
H. duryi eudiscus 

Silver Springs, Marion County. Collected by T. van Hyning 

Geographical Distribution. As far as known, this group is found only 
in the peninsuhi of Florida north to Bradford County. It is particularly 
abundant in the Everglade region of southern Florida. 

Species Considered as Valid. Three species are recognized, one with 
several races. 

Helisoma (Seyninolina) scalare (Jay) Hrlisoina (Seminolina) duryi intercalare 

Helisonia (Seminolina) duryi (Wethcrby) (Pilsbry) 

Helisoma (Seminolina) duryi seminole Helisoma (Seminolina) duryi eudiscus 

Pilsbry Pilsbry 

Helisoma (Seminolina) duryi normalc Helisoma (Seminolina) preglabratum 

Pilsbry (Marshall) 

For an extended account of the species of this subgenus see Pilsbry 
1934, pp. 31-43. 

Geological Distribution. Pliocene to Recent fauna. 

Remarks. SeniinoUna is a characteristic group of Helisoma, differing 
from typical Helisoma in the presence of a physoid shell, not only in one 
distinct species, but in the variations of the races of another species. In 
its anatomy, it differs from typical Helisoma in the rounded mesocone of 
the lateral teeth wiiich are distinctly aculeate in Helisoma. The duct of 
the penial gland is about twice as long as in Helisoma and the penial gland 
is more elongated, narrower, and less cup-shaped than in Helisoma. 

Seminolina is a notable group of the subfamily Helisomatinae and one 
of the most variable genera as regards species. The physoid aspect of its 
type species, Paludina scalaris Jay, led the older conchologists to include 
it in Physa and in the genus Ameria of the family Bulinidae. The largest 
species, Helisoma duryi (Wetherby), is perhaps more variable than any 
other species found in America, its extremes being from typical Physa- 
shaped to flatly discoidal shell. The elongation of the spire always pro- 
duces a physoid aspect. The races of duryi blend into each other and often 
three forms will occur in the same lot, as normale, intercalare, and duryi. 

The Helisoma duryi complex includes several races more or less heavily 
infested with parasitic worms. These include normale, intercalare, eudiscus, 
and duryi. IVIany specimens were so badly infested that most of the organs, 
especially the genitalia and liver, were completely obliterated. Helisoma 
scalare was the least affected. 

Subgenus PIEROSO^IA Ball, 1905 
Tjqie by original designation Planorbis trivolvis Say 

1865. Helisoma Binney (non Swainson), Land and FW. Sh. N. A., II, p. 112. No 

type cited. Includes mostly species belonging to Pierosoma 
1872. Helisoma Tryon (non Swainson), Mon. Univ. FW. Moll. U. S., pp. 188, 198. 

Includes mostly species of Pierosoma. As subgenus 
1883. Helisoma Fischer (non Swainson), Man. de Conch., p. 509. Type Planorbis 

trivolvis Say. As section of Planorbis 
1899. Helisoma Martens (non Swainson), Biol. Cent. Amer. Moll., p. 381. Includes 

species now referred to Pierosoma 



Suhfamilies, Genera, and Subgenera — Recent and Fossil 135 

1905. Pierosoma Dall, Alaska Moll., pp. 81, 85. Type Planorbis trivolvis Say. As 

section under subgenus Helisoma 
1918. P/emso ma Walker, Miscel. Pub. Mus. Zool., Univ. Mich., No. 6, p. 11. Type 

Planorbis trivolvis Say. As section of subgenus Helisoma 
1921. Pierosoma Germain, Rec. Ind. Mus., XXI, pp. 6, 49. Type Planorbis trivolvis 

Say. As subgenus 
1923. Pierosoma Wenz, Fossil. Cat., Pars 22, p. 1522. Genotype H. (Pierosoma) trivol- 
vis (Say.) As svibgenus. 
1926. Pierosoma F. C. Baker, Trans. Wis. Acad. Arts and Science, XXII, p. 202. Type 

Planorbis trivolvis Say. As subgenus 
1928. Pierosoma F. C. Baker, Fresh-water Moll. Wis., I, p. 329. Type Planorbis 

trivolvis Say. Genitalia and radula. As subgenus 
1931. Pierosoma F. C. Baker, Proc. Zool. Soc. London, p. 586. Tjq^e Planorbis trivolvis 

Say. Genitalia and radula. As subgenus 
1931. Pierosoma Thiele, Handbuch, Teil 2, p. 479. Type Planorbis trivolvis Say. 

As section of Planorbis 
1934. Pierosoma Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 30. As subgenus 

Shell (plate 80, figs. 13-15) . Large, sinistral, of few whorls, the last whorl 
large and capacious, the early whorls usually flattened and carinate above, 
widelj^ umbilicate below ; spire of the adult shell usually flattened and sunk 
below the level of the body whorl ; aperture notably expanding, even flar- 
ing in some specimens, the outer lip thickened within; sculpture of coarse 
growth lines and conspicuous spiral lines; surface usually dull, never glossy 
as in Seminolina. 

Animal (plate 70, fig. 7, H. trivolvis macrostomum; fig. 8, H. trivolvis 
Jallax). Body long and somewhat narrow, rounded before, the foot nar- 
rowly pointed behind; velar area well-developed; tentacles long and fili- 
form; eyes at base of tentacles as in other Planorbidae. Color usually 
dark horn, in some species reddish or yellowish, the body flecked with 
streaks or spots; mantle spotted, as in trivolvis, or without spots, as in 
pilsbryi; the head and foot are usually lead color. In the young, the ten- 
tacles are very long and slender, the body dark horn color flecked wath 
white spots; the eyes black; viscera reddish through the shell; foot also 
somewhat reddish, especially on the front portion (plate 70, fig. 6) . 

ANATOMICAL CHARACTERISTICS 
PLATE 24 (Planorbis trivolvis Say) 

GENITALIA. Male Organs (fig. 15) . Seminal vesicle (SV) elongated 
(3.5 mm. long, 0.5 mm. wide) composed of many small vesicles. It occupies 
almost half of the length of the ovisperm duct. Sperm duct (SPD) long and 
narrow (about 4 mm. long) . Prostate (PRS) about 4.5 mm. long and 1 mm. 
wide, composed of fourteen rows of diverticula emptying into a short 
prostate duct which connects with the sperm duct and from which the long 
(15 mm.) vas deferens (VD) extends and passes to the vergic sac. There is 
only a very slight enlargement (epiphallus) of the vas deferens as it enters 
the vergic sac. A cross section of the prostate (fig. 13) shows the fourteen 
rows of diverticula to be of unequal length and the whole section to be 
fan-shaped. 

The penial complex (fig. 11) is usually about 5 mm. long. The prepu- 
tium (PR) is very wide (1.5 mm.) and cylindrical in shape. The vergic 
sac (VS) is of the same length as the preputium but is very narrow, the 
preputium rapidly narrowing as it receives the vergic sac. The vergic sac 



136 The Molluscan Family Planorhidae 

increases to double its diameter near the end where the vas deferens enters. 
There is a single, wide retractor muscle (RM) which may be split into 
several branches (figs. 1, 5). The duct of the penial gland (DC) is very 
long and narrow (8 mm. to 9 mm. long) and extends from the upper part of 
the preputium to a point just above the diaphragm (see fig. 8). Normally 
the duct lies coiled on the preputium just over the jienial gland and ad- 
herent to the preputium, bound down by many small muscles covering the 
preputial sac. There is usually one wide band of sui)porting nuiscle (SM). 
The duct is shown in fig. 5 partly uncoiled. 

Internally (fig. 8), the preputial cavity (PR) contains a number of 
small vertical folds or pilasters. There is a large, cup-shaped penial gland 
(GL) about 1 mm. in diameter, which is contracted near its attachment 
to the body wall of the i)reputium to form a narrow, roundeil neck. The 
duct (DGj passes through the wall of the j^reputium and extends to the 
vergic sac where it enters just above the diaphragm (DV). A vertical sec- 
tion of the gland (fig. 4j shows the circular cup to be of considerable depth 
(about 1 mm.), the inner walls lined with many vertical folds (GF). The 
bottom of the cup contains many small folds placed longitudinally. The 
gland duct (DC) enters the bottom folds of the cup. The walls of the cu]) 
(BW) are very thick. Another form of gland is shown in fig. 14. 

The vergic sac contains the elongated verge (V) which is enlarged at 
the upper end and tajicrs downward to a point. The seminal canal has a 
central exit beyond which a small, triangular papilla extends, as shown in 
fig. 10. There is a large muscular ring or diaphragm (1)1 which is capable 
of considerable extension and contraction, causing the diaphragm to be a 
narrow nmscular ring or a comjiarativcly thin membrane which nearly 
closes the opening between the preputium and vergic sac. Figure 10, some- 
what diagranunatic, shows the relationship between the diaphragm, the 
verge, and the entrance of the penial ghmd (hict. which is a trifle too high 
in the figure. 

The penial complex often assumes a bilobatc lorm, the preputium ex- 
tending ujnvard until it is higher than the vergic sac (fig. Ij. A vertical 
section of such a condition (fig. 2) shows the penial gland to be placed at 
the sununit of the preputial extension. The relationshi]) of the verge and 
the penial gland duct is also shown in this section. In young specimens of 
three and one-half whorls, the prei)utium and vergic sac form a single wide, 
elongate-pyriform i)enial complex with a short penial gland duct (fig. 3). 
This condition is suggestive of typical Helisoma, which has a wide penial 
complex and a short duct, and indicates, it would seem, a develoi)ment of 
the Pierosoma group from the HeUso))ia group. 

Female Organs (fig. 15) . The spermatheca fS) is elongate-pyriform 
and about 2 nun. long. The si)ermathecal duct (SD) is 3 mm. long, narrow, 
and somewhat enlarged at the lower end where it enters the short and 
wide vagina (YG). The uterus (U) is about 7 mm. long, narrow at the 
vagina and widening to double this diameter near the prostate where it 
unites with the nidamental gland (NG), which is wide and bulbous. The 
oviduct (OD) is short and wide (about 3.5 mm. long and 0.5 nun. wide) 
and somewhat coiled. The albumen gland (fig. 7) is sciuarish and is com- 
posed of many small follicles. In side view, it is seen to be cleft to accom- 
modate the passage of the intestine on its lower surface (fig. 6, IN). There 
is a large carrefour (fig. 15, CF) into which the duct of the albumen gland 
enters (DA). 



Subfamilies, Genera, and Subgenera — Recent and Fossil 137 

Hermaphrodite Organs (fig. 15). The ovotestis (OT) occupies about 
one whorl of tlie slieU. It is composed of about thirteen rows of diverticula 
which radiate from the ovisperm duct. In a cross section near the anterior 
end (fig. 9), there are six cliverticula entering the ovisperm duct, four of 
which branch twice, one is simple, unbranched, and one is branched four 
times. The branching is not uniform throughout the ovotestis. The free 
portion of the ovisperm duct (SO) is short, that portion near the ovotestis 
being very short (about 1 mm.). The end near the oviduct is longer (1.5 
mm.). A portion of the duct beyond the seminal vesicle (for about 1.5 mm.) 
is provided with small vesicles along the side which are probably to be 
considered as parts of the seminal vesicle. 

No figures other than those by the waiter (1923, 1931) have been pub- 
lished. The chief characteristic is the large, wide, and somewhat pyriform 
preputium and the very long penial gland duct. This duct is similar in 
mature specimens of the different races and species, but there is some 
variation in the details of the sexual organs, as would be expected. 

The genitalia of the races of Helisoma trivolvis vary in minor details 
which are figured on plate 29. In H. t. pseudotrivolvis { = lentum, figs. 1-6), 
there is considerable variation. Figure 1 shows the penial complex a trifle 
wider than in typical trivolvis. In fig. 2, the penial complex is vertically 
sectioned showing a wider verge and a somewhat differently shai)ed penial 
gland. Figure 3 shows the manner in which the penial gland duct is coiled 
on the outside of the preputium (DC). In fig. 4, the penial gland is shown 
in vertical section, the cup being somewhat diagonal. As this gland is 
capable of some muscular contraction and expansion this variation in 
shape is of no taxonomic importance. In fig. 5, the preputial sac has been 
pushed upward placing the vergic sac on the side of the preputium. The 
form of the penial gland, the verge, and the great length of the penial 
gland duct is indicated. In fig. 6, the penial gland has been protruded from 
the male opening and is lying on the neck of the animal, near the female 
opening. 

The genitalia of a race of trivolvis [lentum) from the type locality, 
New Orleans, Louisiana, are shown in figs. 7-13. Figure 8 shows the gen- 
eral form of the penial complex. In fig. 11, the penial gland has been 
extended from the male opening, and is shown in its typical cup-shaped 
condition. Figure 12 shows the gland exserted with the verge beside it, also 
exserted. In fig. 13, the shape of the entire verge of this specimen is shown. 
It is peculiarly shaped at the distal end. In fig. 7, the penial complex is 
shown in its typical position w^ien the gland is exserted from the male 
opening. The cup-shaped gland (GL) is normal. Characteristics of the 
verge are shown in figs. 9 and 10. Figure 9 shows the entire verge which 
has been sectioned in two places to show^ the location of the sperm canal 
near the center of the verge. The waist-like constriction just above the 
middle of the verge shows where this organ was compressed when it was 
protruded through the muscular ring or diaphragm. The shape and central 
position of the sperm canal outlet is shown in fig. 10, from the front and 
from the side. The small papilla at the end of the verge is well shown. This 
feature is characteristic of all members of the group Pierosoma. 

The large race of trivolvis (macrostomum) differs little from the typi- 
cal form. Figures 14 and 16 on plate 29 show the normal condition of the 
penial complex and fig. 15 a condition in which the preputium has been 
greatly pushed upward. 



138 The MoUuscan Family Plauorbidae 

In H. trivolvis fallax, a small race of trivolvis, a specimen was examined 
in which the penial complex had a very large, pyriform preputiiim and a 
small, cylindrical vergic sac (fig. 17). The penial gland of this specimen 
was quite normal (fig. 18). 

The great variation in the form of the retractor muscle is well shown on 
plate 29, especially in figs. 1, 2, 3, 5, 7, 8, 14, 15, 16, and 17. It varies from 
a narrow band of muscle to a wide band with several branches. 



THE GENITALIA OF SPECIES ALLIED TO TRIVOLVIS 

Species East of the Rocky Mouxt.\ixs 

A closely related species, Helisoma chautauquense F. C. Baker (plate 29, 
figs. 19-22), differs from the trivolvis complex in the wider, more pyriform 
preputium, shorter and wider vergic sac, and especially the much shorter 
penial gland duct (DC) which recalls the Seminolina group (fig. 22). The 
penial gland, however, does not differ from that of trivolvis. In the imma- 
ture stage of this species, the whole penial complex is wider, especially the 
vergic sac, and the gland duct is very short, the whole male organ resem- 
bling that of typical Helisoma (fig. 19). 

In a rather distinct species, Helisoma truncatum (]\Iiles), the genitalia 
are similar in general form but show some minor peculiarities ( plate 26, fig. 
13). The seminal vesicle (SV) is of greater diameter and less length, and 
the ovisperm duct is of slightly greater length (4 mm.). The prostate 
(PRS) is much shorter (1.7 mm.) and wider, and consists of fifteen 
diverticula, which are on a short prostate duct placed at the right edge of 
the group of diverticula (fig. 10). There are about eleven main diverticula, 
several of which are liranciied at the end. The cross section of the prostate 
of truncatian differs slightly from that of trivolvis. The duct of the sperma- 
theca is somewhat longer than in trivolvis. The penial complex is wider 
than in trivolvis and is similar to some of the races, lentum for example 
(figs. 6, 7, 12). The penial gland (fig. 9) does not differ from that of 
trivolvis. 

A larger species, Helisoma pilsbnji (F. C. Baker), living in Wisconsin, 
Michigan, and the northern part of the United States and southern Canada, 
is figured on plate 25. The genitalia (fig. 4) are similar in general form to 
those of trivolvis, but there are some differences. The spermatheca (S) is 
narrower and shorter (1.3 mm.) but the duct is long. The prostate is 
shorter. The seminal vesicle is shorter and wider. The ovotestis diverticula 
are very long. In the penial complex (fig. 5), the preputium is twice as long 
as the vergic sac and both are wider than in tiivolvis. Variations in shape 
and position of the vergic sac are shown in figures 1, 6, and 7. In the penial 
gland, the cup is much shallower than in trivolvis (fig. 2). The genitalia 
are somewhat shorter than in Helisoma corpulentum. 

A larger form than pilsbryi is known as H. pilsbryi infracarinatum 
F. C. Baker which is common in southern Canada. While regarded as a 
race of pilsbryi there are some features of the genitalia which indicate that 
is a very distinct race (plate 25, fig. 13). The seminal vesicle (SV) and 
ovisperm duct (SO) are similar to these organs in pilsbryi, but the prostate 
(PRS) is twice as long (5.7 mm.) and much larger, comparatively. There 



SuhjamUies, Genera, and Subgenera — Recent and Fossil 139 

is also a greater number of diverticula. The spermatheca is twice as long 
(3 mm.) and the duct is longer (3.5 mm.). A cross section of the prostate 
near the lower end shows seventeen rows of long, club-shaped diverticula 
(fig. 12). In the penial complex (fig. 8), the preputium is normally very 
wide, pyriform, with the vergic sac small and narrow and about half as 
long as the preputium. In fig. 9, a penial complex is shown with the 
preputium pushed upward. The immature penial complex (fig. 10) is very 
wide with a short duct, as in other immature forms of Pierosoma. 

Helisoma corpulentum (Say) and its races inhabit the northern part of 
the United States and southern Canada. The genitalia greatly resemble 
those of H. pilsbri/i iniracarinatum. The principal features of the genitalia 
are figured on plate 31. 

In corpulentum (fig. 3), the seminal vesicle (SV) is long and wide (4 
mm. long, 0.7 mm. wide). The prostate is 5 mm. long, 1.5 mm. wide, and 
1.5 mm. high (fig. 2). In cross section, this is seen to be composed of 
twenty long diverticula arranged fan-wise. The ovotestis (OT) occupies 
a trifle over one whorl and consists of about eighteen rows of long divertic- 
ula (fig. 1). The spermatheca (S) is 2 mm. long and is placed at the end 
of a very long duct (5 mm.). In form, the spermatheca is more nearly like 
that of infracarinatum. The normal form of the penial complex is shown 
in fig. 5, the preputium and vergic sac being about equal in length. Figure 4 
shows a specimen in which the vergic sac is shortened and the upper part 
of the preputium has been pushed upward, a common characteristic in 
Pierosoma. The form of the penial complex in immature individuals is 
shown in figs. 6 and 7, fig. 6 being from a younger specimen. 

A race of corpulentum, multicostatum F. C. Baker, has the genitalia 
much as in the typical form. Figures 9 and 10 show the form of the penial 
complex in immature individuals. Figure 11 is from an immature individual 
in which the vergic sac has been lowered to the side of the preputium. 
Figiu'e 12 also shows an immature condition. In fig. 13, the penial complex 
of a fully mature individual is shown, the preputium pushed upward and 
the long penial gland duct uncoiled (it is 14 mm. long). The penial gland 
is shown in section in fig. 8. 

Another race found only in Lake Vermilion, Minnesota, H. c. vermilion- 
ense F. C. Baker, shows no essential differences in its genitalia. The penial 
gland is rather shallow (fig. 15) but this could be from contraction. Figure 
14 shows one form of the penial complex when the j^reputium is pushed 
upward. The gland duct is partly uncoiled. Figures 16, 17, and 18 show 
the penial complex of immature individuals, progressively from 16 to 18. 
The penial duct is short in figs. 16 and 17 but much longer in fig. 18, the 
latter nearer maturitv. Two forms assumed bv the verge are shown in figs. 
17 and 18. 

Helisoma ivhiteavesi F. C. Baker, a related species, apparently rare in 
Canada, is similar in its genitalia to Helisoma corpulentum. The penial 
complex of an adult individual is shown in fig. 19. The vergic sac differs 
from that of the corpulentum group in being very long (5.5 mm.) and 
slender. It is about as long as the preputium. The gland duct is very long 
(24 mm.). Compare fig. 19 with fig. 13, the shells being of the same 
size and age. 

A large Pierosoma, Helisoma magnificum. (Pilsbry) , living in Greenfield 
pond, near Wilmington, North Carolina, resembles the northern pilsbryi 



140 The Molluscau Family Planorbidae 

and corpulentum. The prostate is 7 mm. long and more than 1 mm. wide 
and high. There are thirteen rows of diverticula. The spermathecal duct is 
very long (12 mm.) and narrow, and the spermatheca is 3 mm. long. The 
organs of the female system are long and narrow. The penial complex 
(fig. 20) has a pyriform preputium and a cylindrical vergic sac. The penial 
gland duct is very long. Internally, the complex shows a large gland and a 
cylindrical verge, both nearly filling their respective cavities (fig. 21). A 
cross section of the penial gland is shown in fig. 22. It is much like that of 
trivolvis. 

Species of the Rocky IMountains and Westward 

Several species and races of Pierosoma occur in the western part of the 
United States and Canada. One of the most abundant and widely dis- 
tributed species is Helisoma subcrenatuni (Carpenter), the genitalia of 
which are figured on plate 30 (specimen not quite mature). Figure 15 
pictures the whole genitalia, the organs spread out. The seminal vesicle is 
2 mm. long and is notable for the number of rather long vesicles, princi- 
pally bordering the gland, which is much wider than the ovisperm duct. 
The sperm duct (SPD) is short (2 mm. long) and the vas deferens is 
narrow and about 7 mm. long. The prostate is about 2 mm. long and is 
composed of twenty- four rows of diverticula, arranged fan-wise when seen 
in section (fig. 12). There is a short prostate duct at each end of the 
prostate which joins the sperm duct beneath the prostate. The spermatheca 
(S) is about 1 mm. long and the duct is long and narrow and about 2 mm. 
long. The uterus (U) is narrow anteriorly and widens posteriorly into the 
nidamental gland (NG), which is a large organ 1 mm. wide. The oviduct 
(OD) is a narrow tube about 2 mm. long. 

The penial complex is about 3.5 mm. long in fully adult specimens (figs. 
17, 19). The vergic sac is slightly shorter than the jireputium. The pre- 
putium is widely pyriform while the vergic sac is narrow and cylindrical. 
The penial gland duct is not very long (3 to 4 mm.) and is normally coiled 
on the preputium. In vertical section (fig. 13), the penial complex shows 
a large penial gland (GL), a rather thick diaphragm (D), and a thick, 
somewhat sausage-shaped verge (V). In section, the penial gland (fig. 11) 
is similar to that organ in trivolvis. In immature individuals, the penial 
complex is very wide and the duct is very short (fig. 10). In fig. 15, the 
penial duct and complex is of a young specimen. In adult or old specimens, 
there is more difference between the preputium and vergic sac and the duct 
is always longer. These differences are shown in figs. 17 and 18 (compare 
with figs. 10 and 15). 

The genitalia of subcrenatum differ from those of the trivolvis group 
in the greater number of prostate diverticula, shorter penial gland duct, 
when adult, and the presence of the aculeate vesicles in the seminal vesicle. 

A relative of subcrenatum, H. plexatmn (Ingersoll), is figured on plate 
30, fig. 4 (genitalia). The general characteristics of plexatum are like 
subcrenatum. The seminal vesicle (SV), however, is different in the absence 
of the digitate vesicles and is more like the seminal vesicle in pilsbryi. The 
prostate is 5 mm. long and more than 1 mm. wide. The spermatheca (S) 
is very narrow, over 2 mm. long, and the duct is 5 mm. long or nearly 
three times the length of the spermatheca. It resembles the spermatheca 
of trivolvis. The vergic sac is small and less than half the length of the 



Subfamilies, Genera, and Subgenera — Recent and Fossil 141 

preputium (fig. 1). In vertical section, the penial complex shows the penial 
gland to be compressed as in subcrenatum (fig. 3) and not globular as in 
trivoivis. The penial gland duct is longer than in subcrenatum (figs. 1, 2, 3) , 
resembling trivoivis in this respect (compare figs. 1 and 17). The penial 
gland is shown in section in fig. 5. The verge (V) is large and long ovate 
in form when at rest (fig. 6). The shapes assumed during extension into the 
vergic sac cavity are shown in figs. 7, 8, and 9. The retractor muscles are 
as in subcrenatum. 

The penial complex of a form of subcrenatum from Pass Lake, Fidalgo 
Island, Puget Sound, Washington, is figured on plate 32 (fig. 8). It is 
similar in form to the penial complex of subcrenatum figured on plate 30 
(fig. 17), the preputium, however, being more cylindrical and less pear- 
shaped and the vergic sac is relatively longer. The presence of the two 
small and narrow retractor muscles is noteworthy. 

Another form related to subcrenatum, but believed to be of specific rank, 
is Helisoma horni (Tryon) from Paul Lake, British Columbia. The geni- 
talia are different from both subcrenatum and ple.ratum (plate 26, fig. 3). 
The seminal vesicle is similar to that of plexatum. The prostate is about 
3 mm. long, and 1 mm. wide and has thirteen rows of large, club-shaped 
diverticula (fig. 5). These are much wider and less in number than in 
subcrenatum. The spermatheca (S) is bulbous, about 1 mm. in length and 
the duct is 3 mm. long, widening as it enters the narrow vagina. The 
]icnial complex (fig. 1) has a long vergic sac enlarged at the outer end. 
The preputium is pushed upward. The gland duct is about as long as in 
plexatum. The penial gland (fig. 2) is like that organ in trivoivis. A sec- 
tion through the sperm duct, oviduct and nidamental gland (fig. 4) indi- 
cates the relationship between these organs. 

IMany years ago Tryon described a small Planorbis from Pueblo Valley, 
Oregon, calling it Planorbis oregonensis (now Helisoma oregonense) . This 
species has been one of the rarities of western Planorbidae. Specimens 
collected in Tooele County, Utah, by Mr. J. Henderson belong to this 
species and the anatomy of this small planorbid is now available. On plate 
28, fig. 2, the principal organs of the genitalia are shown. 

The seminal vesicle is about 1 mm. long and the ovisperm duct about 
3 mm. long. The latter bears short lateral vesicles for a large part of its 
length, as in ple.vatum. The prostate is short (about 2 mm. long) and bears 
sixteen rows of long and narrow diverticula (fig. 3). The spermatheca is 
bulbous, about 0.7 mm. in length and connects with the long and narrow 
vagina by a duct slightly more than 1 mm. in length. The shape of the 
spermatheca is like that of horni but the duct is shorter. The penial com- 
plex (fig. 1) has a large, pyriform preputium with the lower part length- 
ened. The vergic sac is short, swollen at the end, and almost half the length 
of the preputium. The penial gland duct is very long (5 mm.). There is 
one retractor muscle (sometimes split into two smaller muscles), attached 
to the lower part of the preputium, and one band of supporting muscle. The 
]ienial gland (fig. 4) is round, rather short, and attached to the wall of the 
preputium by a short, wide neck. In vertical section (fig. 5), the cup is 
circular, with relatively few large vertical folds and a number of pave- 
ment-like folds in the bottom of the cup, to which the gland duct is 
connected (DC). 



142 The Molluscau Family Plauorbidae 

A Helisoma abundantly distributed in California, and believed to be a 
race of the Mexican Helisoma tenue (Phil.), has been named H. tenue 
calij orniense by F. C. Baker. The genitalia are shown on plate 32, fig. 1. 
The seminal vesicle (SV) is wide and long (5 mm.). It swells in the center 
and tapers at each end. It is made up of many small vesicles. The ovisperm 
duct is 5.5 mm. long, narrow, and for two-thirds of its length is bordered, 
on one side only, by many small, rounded vesicles. These are probably part 
of the seminal vesicle system. The sperm duct (SPD) is 3 mm. long and is 
very narrow. The prostate is short ( 1.3 mm. long) and wide ( 1 mm.) and has 
twelve rows of long, club-shaped diverticula (fig. 6, the prostate in section). 
The vas deferens ( VD) is a long, narrow tube 11 mm. long. The sperma- 
theca (S) is pyriform, 1.5 mm. long, with a long, narrow duct about 2.5 
mm. long, enlarged as it enters the long and narrow vagina (VG). The 
ovotestis is made up of very large, club-shaped diverticula in eleven rows. 

The penial complex (fig. 3) has a large, pyriform preputium 2.2 mm. 
long and a cylindrical vergic sac 1.5 mm. long. The penial gland (fig. 5) 
is short and cup-shaped with many vertical folds. Its duct is relatively 
short (5 mm.). Figure 2 shows the penial complex with the preputium 
pushed upward, the vergic sac placed at the side. There is a wide, very 
muscular diaphragm. The verge (fig. 2, V) is wide above but tapers to a 
narrow point below. Figure 7 shows the penial complex of a specimen from 
Prospect Park, near Redlands, California. The preputium is pyriform and 
very wide at the summit. It is 3 mm. long. The verge is 3 mm. in length 
and is not as pyriform in shape as in the other Californian sjiecimens 
examined. The gland duct is over twice as long (14 mm.) as in the Shandon 
specimens. The Prospect Park specimens are very large, which probably 
accounts for the great length of the duct. There is one large retractor 
muscle and one or two supporting muscles. 

The genitalia of calij orniense are peculiar in the great length and size 
of the seminal vesicle, in the very short prostate, and in the sessile 
penial gland. 

One of the largest of west American planorbids is Helisoma traskii 
(Lea). The genitalia of this species are shown in fig. 17 on plate 32. The 
seminal vesicle is shaped like that organ in calif orniense (see fig. 1) and is 
coiled in much the same manner. It is about 9 mm. long (when extended) 
and 1 mm. wide and is composed of many small vesicles. The ovisperm 
duct (SO) is very long (16 mm.) two-thirds of which bears small, widely- 
spaced vesicles on the lateral margin. The sperm duct is 6 mm. long and 
0.5 mm. wide for two-thirds of its length and tapers to about half this 
diameter near the point of contact with the prostate duct. The prostate 
(PRS) is verv long (6.5 mm.) and about one-fourth as wide as long (1.5 
mm. wide) . There is a short prostate duct branch at each end of the sperm 
duct beneath the prostate. In section (fig. 12), the prostate shows fourteen 
rows of diverticula of varying length, unbranched. In the section, the 
nidamental gland (NG) is composed of several large diverticula. The vas 
deferens is a long, narrow tube (25 mm. long). The spcrmatheca (S) is of 
unusual length (3.5 mm.), is club-shaped and is placed at the end of a 
very long duct ( 10 mm.) which enlarges at its point of entrance into the 
short, narrow vagina (VG). The ovotestis (OT) consists of large, club- 
shaped diverticula of varying length, thirteen rows being counted in a 



Subfamilies, Genera, and Subgenera — Recent and Fossil 143 

section at the proximal end of the ovotestis (see fig. 17, OTj. The albumen 
gland ( AL) is squarish and is made up of small follicles. 

The penial complex (fig. 14) has a pyriform i)rei)utium 4 mm. long 
and a sausage-shaped vergic sac 3 mm. long (PR, VS). The penial gland 
duct (DC) is of medium length (9 mm. long) and is a narrow tube. The 
retractor muscle (RM) is wide and is divided into two main branches, 
united at their attachment near the upper part of the preputium. The sup- 
l)orting muscle (SAD is rather narrow and is branched several times in its 
attachment to the upper jiart of the preputium on the opj^osite side from 
the retractor muscle. 

Internally (fig. 11), the preputium has a large penial gland (GL) which 
is attached to the. wall of the preputium by a thick neck or base. Sec- 
tioned vertically (fig. 13) the penial gland is seen to have a large cup 
bordered by large vertical folds (GF). The base of the cup has many 
folds to which the penial gland duct is attached (DC). One specimen of 
fraskii had a bifid tentacle (fig. 16). 

The genitalia of Helisonia trnskii are peculiar in the large prostate, the 
elongated spermatheca on an unusually long duct, and in the generally 
long and narrow uterus and vas deferens. It is different from californiense 
in the size of the prostate and in the size and length of the spermathecal 
duct. The shorter penial gland duct allies traskii with californiense and 
separates it from plexatum. 

Another large species found in California is Helisoma occidentale 
(Cooper), living characteristically in Klamath Lake, Oregon. Unfortu- 
nately, the material had been preserved in formalin and the anatomy could 
not be worked out in a satisfactory manner. The penial complex is like 
that of californiense figured on plate 32, fig. 3. The vergic sac, however, 
is more elongated at the distal end. The greater number of specimens 
examined had the penial complex as shown in fig. 10, the preputium 
pushed upward and the vergic sac attached to the side about halfway 
between the extremities of the penial complex. The penial gland was about 
as in traskii (fig. 13). The verge, coiled in the vergic sac, is shown in fig. 9. 
Other details are not available from these specimens. 

Respiratory and Renal Systems. The pseudobranch of Helisoma tri- 
volvis (plate 24, fig. 12) is very wide, somewhat bilobed, with a narrow 
crest or ridge extending down the rectum (R) and over the pseudobranch 
at about the center. The anal opening is to the left of the ridge. There is a 
large pneumostome (PS). 

The shape of the pseudobranch does not vary to any degree in the 
different species and races of Pierosoma, excepting in the general shape 
which in many cases is broadly rounded below and not bilobed (see plate 
25, fig. 11). Several of these are figured on the following plates: pilsbryi, 
plate 25, fig. 3; infracarinatum, plate 25, fig. 11; truncatum, plate 26, fig. 
11; subcrcnatinn, plate 30, fig. 16; californiense, jilate 32, fig. 4; traskii, 
plate 32, fig. 15. 

The kidney of Helisoma trivolvis (plate 44, fig. 2) is elongated, 12.5 
mm. long and 2 mm. wide at the upper part near the pericardium. The 
ureter is 1 mm. long and is directed backward, parallel to the length of the 
kidney. There is a conspicuous crest or ridge extending down the center of 
the kidney from just below the pericardium to within 1 mm. of the lower 



144 The Molluscan Family Planorhidae 

end of the organ. A cross section of the kidney made at about the middle 
portion (plate 44, fig. 9) shows the ridge to be rather short and narrow 
and placed at about the middle of the kidney. The lumen is rounded and 
the veins at each end are large and placed at the center of the margin of 
the lumen. In the race lentum (plate 44, fig. 11), a section near the lower 
end shows a large, ovate lumen with the veins at the lower corners. The 
ridge is approximately like that feature in trivolvis. In macrostomum, the 
largest race of trivolvis, a section made near the lower end shows a small, 
much-elongated lumen with the veins at the lower lateral corners (fig. 10). 
The whole kidney is much larger and much thicker with a relatively small 
ridge. 

The species and races of Pierosoma show considerable variation in the 
form of the lumen, and especially in the form and position of the ridge, 
which is found in all species of Helisoma and its subgenera. Several of 
these are figured on plate 44 and need no special comment. Those figured 
are: pilsbryi, section near middle, fig. 12; infracarinatum, near middle, 
fig. 17; magnificum, near middle, fig. 14; corpulentum, near middle, fig. 
15; multicostatum, section near lower end, fig. 16; truncatum, near middle, 
fig. 13; subcrenatimi, near middle, fig. 21; plexatuni, section near lower 
end, fig. 22; (compare figs. 21 and 22 and note difference in ridges); 
horni, near middle, fig. 23; occidentale, near middle, fig. 18; depressum, 
near middle, fig. 19 (note difference in two races); traskii, near middle, 
fig. 20; calif orniense, near middle, fig. 24; oregonense, near lower end, fig. 6. 

The kidney of corp^dentum (fig. 3) is somewhat shortened and bent 
toward the pericardium. The ridge is broad at the upper part and then 
narrowed for the greater part of its length. A cross section is shown in 
fig. 15. Compare this with the kidney of trivolvis, figs. 2 and 9. 

The kidney of calif orniense is figured on plate 45 (fig. 4). It is rela- 
tively short and variable in width. A cross section made through the upper 
part (fig. 5, at B in fig. 4) shows the roundly-ovate lumen occupying the 
greater part of the kidney, with the veins at the middle on each side. A 
section made near the lower end of the kidney (fig. 6, at A in fig. 4) shows 
a very wide and flattened lumen with the veins at each end, and a high, 
pointed ridge. Compare with fig. 21 on plate 44. 

Digestive System. The digestive system of Helisoma trivoh'is (plate 
48. figs. 1,2) is cliaracteristic of that of all species of Pierosoma. The size of 
the organs differs in the various species. The oesophagus (OE) is a narrow 
tube as it leaves the buccal sac, increasing several times in diameter as it 
passes to the crop portion of the stomach. It is about 10 mm. long. The 
stomach is composed of a short crop (CR) , a bilobed gizzard (GZ) , and an 
elongated pyloris (PY). The intestine (IN) makes a complete turn over 
the oesophagus, extends backward around the liver, performs another 
loop, and runs forward to the columella muscle. The intestine is 33 mm. 
long from the end of the pyloris to the rectum. The rectum is 10 mm. long, 
is larger in diameter than the intestine, and is particularly characterized 
by the presence of a frilled crest or ridge (RD) which extends the whole 
length of the rectum and ends over the pseudobranch. In fig. 2, the stomach 
is seen from below showing the position and form of the blind sac or 
caecum (BS) which is attached to the pyloris just below the opening of the 
liA^er (OLV). This blind sac is present in all species of Pierosoma. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 145 

The buccal sac (BP) is a pear-shaped organ, 2 mm. long and 1.5 mm. 
high. The oesophagus leaves the oral cavity near the upper posterior por- 
tion of the pouch. There are two strong buccal retractor muscles (BR). 
The salivary glands (SG) are two in number, 3 mm. long, which enter the 
buccal cavity near the oesophagus by a long, narrow duct (1 mm. long) 
on each side. The salivary glands form a loop, their posterior ends 
connected. 

There is not much variation in the form of the buccal sac in Pierosoma. 
In some species, as pilsbryi, corpulentum, tenue californiense, and sub- 
crenatum (plate 70, fig. 12), the whole sac is a trifle more elongated, espe- 
cially in the fore part. There is reason to believe, however, that the more 
elongated aspect may be due to distortion in the animal when killed. At the 
back end of all sacs there is a rounded or elongated radula sac (plate 70, 
fig. 13, RL) which has to do with the formation of the radula membrane. 
This varies in form in some of the species. 

The jaw in Pierosoma is always of three parts. The superior jaw is 
oblong, wide and low, sometimes somewhat arcuated. The face of the 
superior jaw is marked by fine striations which form a more or less 
denticulate border to the jaw when seen with high magnification. There 
are two long and narrow lateral jaws one on each side bordering the lips 
of the animal, and usually seen in the form of a question mark. The jaw of 
Helisoma trivolvis is shown on plate 49, fig. 2, and this is characteristic 
of all members of the subgenus. The jaws of some other species are figured 
as follows: 

truncatum, plate 49, fig. 3; pilsbryi, fig. 5; infracarinatum, fig. 8; corpu- 
lentum, fig. 15; magnificujji, fig. 16; oregonense, fig. 6; subcrenatum, fig. 7; 
horni, fig. 9; plexatum, fig. 10; traskii, fig. 12; occidentale, fig. 13; 
californiense, plate 50, fig. 1. 

Radula. The radula of Pierosoma is similar to that of Seniinolina in 
the bluntly rounded mesocone of the lateral teeth. The radula of the type 
species, Helisoma trivolvis, is shown on plate 55, fig. 1. 

The center tooth has two spade-shaped cusps which do not reach the 
lower margin of the base of attachment. The lateral teeth (1-10) have a 
quadrate reflection which is tricuspid, the entocone and ectocone sharp 
and spade-shaped, the mesocone rounded. The intermediate teeth (11-13) 
have the reflection somewhat narrower and more elongated than the lateral 
teeth, the entocone breaking up into three small, sharp cusps and the 
ectocone region developing two or three cusps above the ectocone on the 
outer margin of the tooth. Marginal teeth (14-18) still narrower, claw-like, 
with the entocone broken up into four to five small cusps and the ectocone 
into four or more small cusps on the upper, outer margin of the tooth. The 
extreme outer marginal teeth are small, very narrow, and with slight 
denticulations. There is some variation from the type described above, 
some of the lateral teeth developing two cusps in place of the one ectocone, 
as shown in fig. 4. 

The radulae of the races of trivolvis differ little from the type species. On 
plate 55, several of these arc shown, lentum (figs. 6, 7) and pseudotrivolvis 
(=lentum) figs. 2, 3. The radula of the large race, macrostomum, is shown 
on plate 56. fig. 2. In chantaiiquerise (plate 55, fig. 5), the lateral teeth 
(1-11) are narrower than in trivolvis. In winslowi (plate 56, fig. 1), the 



146 The Molluscan Family Planorhidae 

lateral teeth are also narrower. In pilsbryi (plate 56, fig. 3) and injra- 
carinatum (plate 56, figs. 4, 5) the laterals are more quadrate, similar to 
those of trii'olvis, but the marginals show some variation. In truncatum 
(plate 57, figs. 1, 2) the laterals are narrower (as in chautauquense and 
winslowi) . In several laterals of truncatum, there was observed to be con- 
siderable splitting of the entocone and ectocone cusps (see fig. 2, plate 57, 
teeth 1, 5-10). In the large magnificum, the intermediate teeth are very 
long and narrow, the ectocone is placed high up on the margin, and the 
extra cusps of the entocone appear later m the series (plate 57, fig. 4, 
21-26). The marginal teeth are also narrow and the cuspidation is different 
from that in trivolvis and other species of Pierosoma (fig. 4, 27-41). In 
corpulentum, the teeth are arranged in a similar manner to those of 
trivolvis (plate 57, fig. 3). The races vermilionense and multicostatum 
(plate 58, figs. 2, 3) are similar in form. In whiteavesi (plate 58, fig. 1), 
the teeth are similar in form to those of the corpulentum group. 

In the western group of Pierosoma, Helisoma plexatum has narrower 
lateral teeth than trivolvis (plate 59, fig. 1). In specimens from another 
locality, however, the early laterals are quadrate (fig. 2). In specimens of 
plexatum from Rexburg, Idaho, many of the laterals, and some of the 
marginals, in one specimen had the mesocone broken and wavy and 
otherwise modified (plate 58, fig. 4). Other individuals were normal (fig. 
5). A lateral and two intermediate teeth of a specimen from Smartweed 
Lake, Colorado, are shown in fig. 6 on plate 58. A form of subcrenatum 
from Pass Lake, Puget Sound, Washington, has quadrate teeth, similar to 
those of trivolvis (plate 59, fig. 5). Another form from Lost Lake, Puget 
Sound, had very wide, low lateral teeth (plate 60, fig. 1). In one specimen 
from this locality, the center tooth of the eighty-eighth row had seven 
small cusps and the fifth lateral had two sharp entoconic cusps (plate 60, 
fig. 2). Specimens from Skagit County, Washington, were normal, with 
quadrate laterals (plate 60, fig. 2). 

Typical subcrenatu)n from Cottonwood Pass, near Gypsum, Colorado, 
is shown on plate 61, fig. 2. There are eight subquadrate lateral teeth and 
four intermediate teeth. The marginal teeth are normal as to cuspidation. 
An allied species, horni, has a large, somewhat obliquely formed mesocone 
on the lateral teeth, which are not as quadrate as in subcrenatum (1-9), 
the intermediate teeth are narrow and the entocone and ectocone are not 
broken into smaller cusps (10-14). The marginal teeth (15-32) are less 
cusjiidate than similar teeth in subcrenatum. The outer marginals (32) are 
small and more or less vestigial (see plate 60, fig. 7). 

The large traskii from Kern Lake, California, is peculiar in several 
respects (plate 60, figs. 4-6). A nearly complete row (the ninetieth) is 
shown in fig. 5. In the center tooth, the two large cusps extend a consid- 
erable distance below the lower margin of the base of attachment. The 
lateral teeth (1-8) are longer than wide and are unmodified tricuspid. The 
intermediate teeth (9-10) have the entocone and ectocone split into small 
cusps. The marginal teeth (11-22) arc wide and the denticulation is very 
irregular, small interstitial cusps appearing among the larger cusps in some 
teeth (as 11, 13, 14, 17). In another row (eightieth), the last intermediate 
tooth and the first marginal tooth were peculiar in this respect (fig. 6). In 
the eighty-second row of another sjiecimen, this feature was well marked 
(% 4). 



SubfaffiUies, Genera, and Subgenera — Recent and Fossil 147 



In another large species of Pierosoma from Klamatli Lake, Oregon 
(occidcntalc, plate 61, fig. 1), the teeth are more uniform with but little 
splitting of the cusps. The radula differences between the two species 
occidentale and traskii are very marked, as shown on plates 60 and 61. 

In specimens of tenue calif orniense from Shandon, California (plate 63, 
fig. 2) , the center tooth has two wide, spade-shaped cusps- extending below 
the base of attachment. The laterals (1-11) are at first wider than high, 
the cusps rather short, but toward the marginal teeth they become nar- 
rower. The entocone and the ectocone tend to split in some teeth (as 1, 3, 
6, 7). There is one narrow intermediate tooth (12). The marginal teeth 
(13-19) are narrow, the entocones 4-6 cuspidate. In the 100th row of 
the same membrane, the entocone and ectocone of the lateral teeth were 
largely modified by splitting (see fig. 2). 

In a radula from a specimen living in the San Bernardino Mountains, 
there were eleven laterals, one intermediate tooth " and nine or more 
marginals. No splitting was observed in this radula but in another mem- 
brane all of the laterals were abnormal (plate 59, fig. 4) in the sixtieth 
row, small cusps appearing irregularly on the entoconic region. The en- 
tocone of the first lateral was broken up into four small cusps. The inter- 
mediate and marginal teeth were narrow and many of them abnormal in 
the splitting of the entocone (as 14, 16, 17). The mesocone in all teeth 
was more or less irregular. In fig. 6, a very abnoniial eleventh tooth from 
another specimen is figured. The relatively small species oregonense (plate 
61, fig. 3) has narrow laterals (1-8) and intermediate teeth (9-10). The 
marginals are normal for the group. 

The radula formulae of the different species vary more or less and the 
individual radulae may differ in number of teeth in a row. For comparison 
all of the species of Pierosoma which have been examined, together with 
all of the localities represented, are shown in the following table. This 
also indicates the material studied and the source from which the material 
was obtained. ]\Iore specimens were dissected for the genitalia than for the 
radulae. From one to seven specimens of each were examined. 



Species 
trivolvis 
trivoli'is 
trivolvis 
trivolvis 
trivolvis 
pseiidotrivolvis 

( =le}itum) 
pseudotrivolvis 
pseudotrivolvis 
pseudotrivolvis 
pseudotrivolvis 
pseudotrivolvis 
lentum 
fallax 

macrostotnum 
viacrostomum 
macrostomum 
macrostnmum 
chautnuquense 
truncatum 
winslowi 



Formulae 
23-1-23 to 26-1-26 
23-1-23 to 24-1-24 
23-1-23 to 24-1-24 
23-1-23 to 25-1-25 
23-1-23 to 24-1-24 
23-1-23 to 24-1-24 



Locolity 
Canandaigua L., New York 
Green Lake, Wisconsin 
Devils Lake, Wisconsin 
Murphy Creek, Wisconsin 
Sturgeon Bay, Wisconsin 
St. Joseph, Illinois 



24-1-24 to 25-1-25 Peoria, Illinois 

22-1-22 to 24-1-24 Reelfoot L., Tennessee 

23-1-23 to 24-1-24 Mammoth Spgs., Arkansas 

24-1-24 Ada Lake, Oklahoma 

23-1-23 to 25-1-25 Trinity R., Texas 

26-1-26 to 28-1-28 New Orleans, Louisiana 

26-1-26 to 28-1-2S Near Boston, Massachusetts 

27-1-27 to 30-1-30 Bayfield, Wisconsin 

27-1-27 Moose Ear Creek, Wisconsin 

31-1-31 to 32-1-32 Saskatoon, Canada 

37-1-37 to 39-1-39 L. Grauveau, Canada 

24-1-24 to 26-1-26 Chautauqua L., New York 

20-1-20 to 21-1-21 Winnel)ago L., Wi-sconsin 

27-1-27 to 29-1-29 Arbor Vitae L., Wisconsin 



Rows 


Collector 


14.3-167 


F. C. Baker 


148 


F. C. Baker 


126 


F. C. Baker 


150-152 


F. C. Baker 


110-134 


F. C. Baker 


141-167 


F. C. Baker 


149 


F. C. Baker 


180 


Mr. Firkins 


131-155 


C. A. Llovde 


150-160 


A. D. Buck 


150-181 


E. P. Cheatum 


147-186 


E. C. Faust 


144-170 


W. J. Clench 


180 


F. C. Baker 


185 


F. C. Baker 


173 


D. S. Ra\A'son 


154-210 


A. LaRocque 


127 


F. C. Baker 


126-129 


F. C. Baker 


125 


A. R. Cahn 



148 



The Molluscan Family Plaiiorbidae 



maqnificum 

pihhryi 

pilsbryi 

pilsbryi 

filsbryi 

itifnicdriiitdum 

injrdciin nittam 

infracarinatum. 

infracarinatum 

infracarinatum 

corpulentum 

corpulentum 

corpulentum 

multicostatum 

rmdticostatum, 

viulticoi^tntum 

rcrmilidiicnse 

vermiUuncnse 

ivhiteavesi 

subcrenatum 

subcrenatum 

var. 
subcrenatum 

var. 
subcrenatum 

var. 
subcrenatum 
plexatum 
plexatum 
plexatum 
plexatum 
plexatum 
horni 
oregonense 
occidentale 
traskii 
californiense 
calif orniense 
californiense 



42-1-42 
27-1-27 
27-1-27 
28-1-28 
28-1-28 
32-1-32 
31-1-31 
25-1-25 
30-1-30 
32-1-32 
36-1-36 
25-1-25 
32-1-32 
40-1-40 



to 43-1-43 
to 29-1-29 
to 29-1-29 
to 29-1-29 



to 37- 

to 38- 
to27- 
to37- 
to 35- 
to 41- 
to 28- 
to 35- 
to45- 



1-37 
1-38 
1-27 
1-37 
1-35 
1-41 
1-28 
1-35 
1-45 



38-1-38 to 41-1-41 
30-1-30 to 37-1-37 
30-1-30 to 31-1-31 
25-1-25 to 27-1-27 
36-1-36 to 42-1-42 
25-1-25 to 27-1-27 
29-1-29 to 32-1-32 



Wilmington, North Carolina 
Chetek L., Wisconsin 
Prairie L., Wisconsin 
Chetek L., Wisconsin 
Moose Ear Creek, Wisconsin 
Basswood R., Ontario 
Bimaji L., Ontario 
As above (immature) 
Mille Lacs, Ontario 
Rideau R., Ontario 
Lake La Croix, Ontario 
As above (immature) 
Knife Lake, Minnesota 
Kahnipiminanikok L., 

Minnesota 
Mille Lacs swamp, Ontario 
As above (immature) 
Vermilion L., Minnesota 
As above (immature) 
Mille Lacs, Ontario 
Gypsum, Colorado 
Pass Lake, Washington 



180 

180-185 

205 

185 

185 

140-163 

140-151 

140-153 

140-155 

171-177 

165-190 

109-117 

140-150 

163-170 

145-150 

152 

120-123 

119 

139-154 

123-130 

150-160 



P. Bartsch 
F. C. Baker 
F. C. Baker 
F. C. Baker 
F. C. Baker 
A. R. Cahn 
A. R. Cahn 
A. R. Cahn 
A. R. Cahn 
A. LaRocque 
A. R. Cahn 
A. R. Cahn 
A. R. Cahn 
A. R. Cahn 

A. R. Cahn 
A. R. Cahn 
F. C. Baker 
F. C. Baker 
A. R. Cahn 
J. Henderson 
J. Henderson 



28-1-28 to 29-1-29 Lost Lake, Washington 



134-146 J. Henderson 



28-1-28 to 31-1-31 Ponchlla L., Washington 175-180 J.Henderson 

30-1-30 to 32-1-32 McMurrav, Washington 150-170 J.Henderson 

26-1-26 to 30-1-30 Columbine L., Colorado 140-173 J. Henderson 

25-1-25 to 30-1-30 Smartweed L., Colorado 155-170 J.Henderson 

26-1-26 to 30-1-30 Grand Mesa, Colorado 155 J. Henderson 

27-1-27 to 28-1-28 Gocseberrv Creek, Utah 150-165 J. Henderson 

27-1-27 to 31-1-31 Rexburg, Idaho 145-155 J. Henderson 

32-1-32 Paul Lake, British Columl)ia 110-114 D. S. Rawson 

20-1-20 to 21-1-21 Tooele Co., Utah 111-117 J.Henderson 

31-1-31 to 32-1-32 Klamath L., Oregon 150-160 J.Henderson 

28-1-28 to 30-1-30 Kern Lake, California 161-182 S. Siegfus 

24-1-24 to 25-1-25 Shandon, California 155-160 Hanna & Church 

26-1-26 to 27-1-27 San Juan R., California 150 J. D. Hanna 

24-1-24 to 27-1-27 Near Redlands, California 140-157 S. S. Berrv 



T.\BLE Showing Range of Formulae in Different Species 



2S to 27 
trivolvis 
pseudotrivolvis 
chautauquense 
californiense 



25 to 28 
fallax 
lentum 
subcrenatum 
plexatum 



20 to 21 
truncatum 
oregonense 



28 to 32 
subcrenatum var. 
occidentale 
traskii 



32 to 47 
infracarinatum 
corpulentum 
multicostatum 
whiteavesi 
horni 



This table shows that, while there is wide variation in the formulae of 
the radulae in Pierosoma, the range within the species is fairly constant. 
The difference in many membranes is due to the presence of several extra 
marginal teeth on some radulae which do not appear on others. It is to be 
observed, also, that the immature animal usually has a smaller formula 
than the same species when adult. This is noted in the table under several 
species {infracarinatum, corpulentum, vermilionense, and multicostatum). 
Magnificum has the largest formula, 42-1-42 to 43-1-43. 

Geographical Distribution. The subgenus Pierosoma is distributed 
from Ungava, Labrador, Mackenzie, and Alaska southward to Georgia, 
Louisiana, Texas, and California, the whole of Mexico, and southward, on 
the west coast of South America, to Peru. In the West Indies, it is known 



Subfamilies, Genera, and Subgenera — Recent and Fossil 149 

from Cuba, Jamaica, Haiti, and other islands. The metropohs of the group 
is in North America, principally in southern Canada and northern United 
States, where the largest number of species and races is found. Southward 
the number of species rapidly decreases, only two species being known from 
South America and four from the West Indies. These appear to be species 
which have migrated southward in past geological time, possibly by the 
aid of migrating birds. 

In the recent fauna, no member of the Helisoma group is found outside 
of North and South America. In Pleistocene deposits, however, a form of 
Helisoma allied to trivolvis has been reported by Lindholm (1933) from 
the Kolyma River in northeast Siberia beyond the Arctic Circle. It would 
appear that this planorbid is not referable to trivolvis but to some form 
like horni or subcrenatum. The latter species is common in northwestern 
British America and also occurs in Alaska. The Siberian form should 
probably be allied with subcrenatum. Lindholm called it Helisoma trivolvis 
koly7nense but it might be better to designate it simply as Helisoma koly- 
mense Lindholm until more is known about its affinities. As suggested by 
Pilsbry (1933, p. 137), it might represent a migration by the way of the 
old land bridge between Alaska and Siberia, used by both man and other 
mammals during Pliocene and Pleistocene times. 

Species Considered as Valid. The large number of species attributable 
to the genus Helisoma, subgenus Pierosoma, are listed below. The names 
Helisoma (Pierosoma) are understood to be prefixed before each specific 
name in the list. 

ammon (Gould) plexatmn (Ingersoll) 

binncyi (Tryon) salvini (Clessin) 

calodermum (Pilsbry) subcrenatum subcrenatum (Carpenter) 

caribaeum caribaeum (d'Orbigny) subcrenatum disjectum (Cooper) 

caribaeum guatemalense (Clessin) tenue tenue (Philippi) 

chnutauquensc F. C. Baker tenue boucardi (Fischer and Crosse) 

contrcrasi (Pilsbry) tenue calij orniense F. C. Baker 

corpulentum corpidentum (Say) tenue chapalense (Pilsbry) 

corpulentum vermilionense F. C. Baker tenue exaggeratum (Martens) 

costaricense (Preston) tenue pertenue F. C. Baker 

equatorium (Cousin) (= applanatus Martens preoccupied) 

eyerda??ii Clench and Aguayo tenue sinuosum (Bonnet) 

jovenle (Menke) {^ affine C. B. Adams) tenue strebeUanum (Fisch. and Crosse) 

horni (Tryon) traskii (Lea) 

kolymense Lindholm trivolvis trivolvis (Say) 

viagnificum (Pilsbry) trivolvis fallax (Haldeman) 

mullicostatum multicostatum F. C. Baker trivolvis lentum (Say) 

multicostatum whiteavesi F. C. Baker trivolvis macrostomiim (Whiteaves) 

occidentale occidentale (Cooper) trivolvis turgiduni (Jeffreys) 

occidentale depressum F. C. Baker (= intertextum (Sowb.) ) 

oregonense (Tryon) truncatum (Miles) 

peruvianum (Bred.) tumens (Carpenter) 

pilsbryi pilsbryi (F. C. Baker) winslowi (F. C. Baker) 

pilsbryi injracarinatum F. C. Baker ivyldii (Tristram) 

Remarks. Pierosoma is a very distinct group of Helisoma, distinguished 
from the subgenera Helisoma and Seminolina by peculiarities of genitalia 
and radula. The duct of the penial gland is always longer in adult animals 
than in the other groups mentioned. Some of the special anatomical features 
have been described and figured in the preceding pages. The shell is large 
and distinctly sinistral, especially in immature specimens. Pierosoma is the 
dominant planorbid group in North America north of ]\Iexico. 



150 The Molluscan Family Planorbidae 

Subgenus PLANORBELLA Haldeman, 1842 
Type by original designation Plnnorbis campanulatus Say 

1842. Planorbella Haldeman, Mon. FW. Univ. Moll., Physidae, p. 14. Type Planorbis 

campanulatus Sa}' (plate 1, figs. 7-11, 1844) 
1861. Adula H. Adams, Proc. Zool. Soc, p. 145. Type Planorbis midtivolvls Case. 

Non Adula H. and A. Adams, 1857 
1865. Planorbella Binxey, L. FW. Sh. N. A., II, p. 109. Type Planorbis campanulatus 

Say. As subgenus 
1865. Adula Binney, op. cit., p. 111. Type Planorbis midtivolvis Case. As subgenus 

1869. Ancaeus H. Adams, Proc. Zool. Soc., p. 275. Non Ancacus Fauvel, 1863. In place 

of Adula, preoccupied 

1870. Planorbella Dall, Ann. Lye. Nat. Hist. N. Y., IX, p. 351. Tj'pe Planorbis 

campanulatus Say. As subgenus 

1870. Adula Dall, op. cit., p. 351. Type Planorbis multivolvis Case. As subgenus 

1870. Planorbella Tryon, Contr. Hald. Mon., pp. 188, 196. Type Planorbis campanu- 
latus Sa.y. As subgenus 

1870. Adula Tryon, op. cit., pp. 188, 197. Type Planorbis multivolvis Case. As sub- 
genus 

1883. Planorbella Fischer, Man. de Conch., p. 509. Type Planorbis campanulatus Say. 
As section of Planorbis 

1883. Adula Fischer, Man. de Conch., p. 509. Type Planorbis multivolvis Case. As 

section of Planorbis 

1884. Planorbella Tryon, S. and S. Conch., Ill, p. 106. Type Planorbis campanulatus 

Say. As subgenus 

1884. Adula Tryon, op cit., p. 106. Type Planorbis multivolvis Case. As subgenus. 

1886. Adula Clessin, Conch. Cab., XVII, p. 33. Tyjie Planorbis multivolvis Case. As 
subgenus 

1886. Planorbella Clessin, op. cit., j). 33. Type Planorbis campanulatus Say. As 
subgenus 

1902. Planorbella F. C. Baker, Moll. Chi. Area, II, p. 294. Type Planorbis campanu- 
latus Say. As subgenus 

1905. I'lanorbella Dall, Alaska Moll., pp. 81, 85. Type Planorbis campanulatus Say. 
As section of subgenus Helisoma 

1912. Planorbella Hannibal, Proc. Mai. Soc. London, X, p. 159. Type Planorbis 
campamdatus Say. As subgenus 

1918. Planorbella W.\lker, Miscel. Pub. Mus. Zool., Univ. Mich., No. 6, pp. 12, 94. 
Type Planorbis campanulatus Say. As subgenus 

1921. Planorbella Germ.\in, Rec. Ind. Mus., XXI, pp. 7, 66. Type Phniorbis cam- 
panulatus Sa3\ As subgenus 

1926. Planorbella F. C. Baker, Trans. Wis. Acad. Sci. Arts, XXII, p. 202. Type Pla- 

norbis campanulatus Say. As subgenus 

1927. Hypsogyra Lindholm, Trav. Com. I'Etude Lac Baikal, II, p. 181. New name 

for Adula H. Adams, 1861, preoccupied 

1928. Planorbella F. C. Baker, Fresh-water Moll. Wis., I, p. 345. Type Planorbis 

campanulatus Say. Radula and genitalia. As subgenus 

1931. Planorbella F. C. Baker, Proc. Zool. Soc, p. 586. Type Planorbis campanulatus 
Say. Genitalia and radula. As subgenus 

1931. Adula F. C. Baker, op. cit., p. 566. Type Planorbis nudtivolvis Case. As syn- 
onym of Planorbella 

1931. Hypsogyra Thiele, Hantlbuch, Teil 2, p. 479. Type Planorbis multivolvis Case. 
As section of Planorbis 

1931. Planorbella Thiele, Handbuch, Teil 2, p. 479. Type Planorbis campanulatus 
Sa.y. As section of Planorbis 

Shell. Sinistral, of medium size, resembling Pierosoma in general form 
but the last whorl notably restricted behind the aj^erture which is campan- 



Kiubjcunilies, Genera, and Suhgenera — Recent and Fossil 151 

iilate (plate 80, figs. 16-18, campamdatum (Say) ; figs. 19-21, multivolvis 
(Case) ). 

Animal (plate 70, fig. 1, campanulatum) . With short, wide foot, oval in 
shape, otherwise like Pierosoma. Color dark reddish brown or blackish, 
bottom of foot very dark reddish with flecks of white, tentacles dark 
colored with indistinct white rings. There is some variation in the shades 
of color. The animal is usually very slow in movement. 

ANATOMICAL CHARACTERISTICS 
PLATE 27 {Hclisotna campanulatum (Say) ) 

GENITALIA. Male Organs (fig. 15). The seminal vesicle (SV) is short 
and wide (about 2 mm. long and 0.5 mm. wide) and the vesicles are very 
large and comparatively few in number. They are mostly attached later- 
ally. A few short \'esicles extend down the ovisperm duct for about 1 mm. 
The sperm duct (SPD) is about 4 mm. long and 0.3 mm. wide. The 
prostate (PRS) is long (4.5 mm.) with a short prostate duct at each end 
which connects with the sperm duct and the vas deferens. There are 
fourteen rows of diverticula of varying length, the median ones the largest, 
the outer ones the smallest. Some of the diverticula arc branched toward 
the end, the section figured (fig. 12) showing four such branches. The 
section also shows the fan-like pattern of the diverticula. The vas deferens 
(VD) is a long and narrow duct (16 mm. long). 

The penial complex (fig. 11) is much like that of Helisoma trivolvis. 
The i^reputium is distinctly pear-shaped, 1.5 mm. long, the vergic sac (VS) 
smaller, shorter (1.5 mm. long) and club-shaped, and very narrow at its 
junction with the preputium. The penial gland duct (DC) is very long 
(5.5 mm.) and narrows considerably at each end where it enters the pre- 
putium and the vergic sac. Normally, the long penial gland duct is coiled on 
the preputium between this organ and the vergic sac, as shown in fig. 9, 
DC. Usually, there is one more or less branched retractor muscle (R^l) 
but in some specimens two retractors were observed (fig. 9). There are 
several (1-3) narrow supporting muscles (figs. 5-8, 10, 11) or there may be 
one wide band with several smaller muscles. In fig. 9, two small muscles 
are shown below the retractor muscles. These are attached to the wall of 
the mantle cavity and not to the columella muscle. 

Internally (fig. 10), the preputium has several vertical folds or pilasters 
and a muscular, cup-shaped penial gland (GL) which is attached by a 
small neck to the wall of the upper third of the preputium. In section 
(fig. 1), the gland is cup-shaped, one side of the cup being thicker than 
the other as shown in the figure (BAV). There are many vertical, thick- 
walled folds (OF) and a number of small, flat, pavement-like folds in the 
bottom of the cup from which the gland duct (DC) proceeds to the 
exterior of the preputium. The space between the preputium and the vergic 
sac is almost closed by a thick muscular ring or diaphragm (fig. 3, D) 
which is dependent between the walls of the preputium. The penial gland 
duct enters the vergic sac immediately above this diaphragm (DY). The 
verge (fig. 10, V) is club-shaped, tapering rapidly toward the end. 

In figs. 5 to 7, the penial complex of H. campanulatum s))iithi is shown 
indicating how the preputium becomes pushed upward and the vergic sac 



152 The MoUuscan Family Planorbidae 

appears to descend to the middle of the preputium. In fig. 8, the penial 
complex of H. campanulatum canadense is shown with the preputium 
notably pushed upward. 

Female Organs (fig. 15). The spermatheca (S) is very long (2.5 mm.), 
sac-like and tapers to the long (5.5 mm.), narrow spermathecal duct (SD). 
The vagina (VG) is 1 mm. long and is very narrow. The uterus (U) is 
long (7.5 mm.) and narrow. The nidamental gland (NG) is about 4 mm. 
long, very wide, and sac-like. The free oviduct (OD) is about 2 mm. long 
and is about twice as wide as the sperm duct. There is a large, elongated 
carrefour (CF). The albumen gland (fig. 2) is ovately rounded and is 
composed of many small follicles. The space for the passage of the intes- 
tine is conspicuous (fig. 2, IN). 

Hermaphrodite Organs (fig. 15). The ovotestis (OT) consists of 
eight or more rows of club-shaiied diverticula, some of which may branch 
two or three times, as shown in the section fig. 4 (FOV), this branching 
rendering the counting of rows difficult. The figure shows fourteen rows on 
the surface and but eight entering the ovisperm duct. The free portion of 
the ovisperm duct (SO) is 3 mm. long near the oviduct but only 1 mm. 
long near the ovotestis. 

The only previous description and figures of the genitalia of Helisoma 
camqiamdatum are by F. C. Baker ( 1931, p. 585, plate iv) where the penial 
complex is shown (plate 27. figs. 10-11 of this work). 

Respiratory and Renal Systems. The pseudobranch (plate 27, fig. 13) 
is leaf-shaped, broadly ovate, with a ridge down the center which is a con- 
tinuation of the ridge on the rectum (R). The pneumostome is large. 

The kidney (plate 45) is similar to that of Pierosoma as represented 
by Helisoma trivolvis. Sections through the kidney of H. campamdatum 
irisconsinense are shown in figs. 15, 16, and 17. In fig. 15, the section 
through the upper part shows a large rounded lumen with a large vein on 
each side near the middle. The ridge does not begin until lower down on 
the kidne3^ Figure 16 shows a section through the middle of the kidney. 
The lumen is larger than in fig. 15, the veins are at the lower part on each 
side, and the ridge is just beginning to show. In fig. 17, taken through the 
lower part of the kidney, the lumen is smaller, the veins relatively larger, 
and the ridge forms a high crest. All varieties of campamdatum show 
essentially this form of kidney. 

Digestive System. The general digestive system does not differ from 
that of Helisoma trivolvis. The buccal sac is much elongated, differing in 
this respect from many of the species of Pierosoma. 

The jaw (plate 49). The superior jaw (of smithi, fig. 11) is elongated 
and low, somewhat arched, its face covered with vertical striations as 
shown in fig. 20. The lateral jaws are about as in Pierosoma. 

The radula (plate 62). Typical campamdatum (fig. 1) has a w'ide, 
bicuspid center tooth, the cusps not reaching the lower margin of the base 
of attachment. The lateral teeth (1-7) are squarish, tricuspid, with the 
mesocone bluntly rounded, the entocone and ectocone aculeate. The inter- 
mediate teeth (8-9) have smaller, sharper mesocones and the entocone 
and ectocone are modified by the addition of smaller cusps. The marginal 
teeth (10-13) are long and narrow, somewhat claw-like, with the entocone 
wide and armed with from four to eight small cusps. The mesocone is small 



I 



Rows 


Collector 


120 


F. C. Baker 


125 


A. R. Cahn 


1.32 


F. C. Baker 


123-129 


A. R. Cahn 


139 


A. R. Cahn 


130-135 


F. Smith 



Subfamilies, Genera, and Subgenera — Recent and Fossil 153 

and spade-shaped. The ectocone is modified to form three small cusps. The 
outer marginal teeth (20) are simply serrated and much smaller than the 
earlier marginal teeth. 

The races icisconsine?ise and canadense (figs. 2, 3) differ little in their 
radulae from typical canipanidatum. H. campamdatum smithi is also 
similar (fig. 4), the lateral teeth showing a gradual change in the form of 
the mesocone. The teeth 6-9 might all be called intermediate, since the 
mesocone is alike in all. Smithi has a larger tooth formula than any of the 
other races of campanulatum. The radulae of the subgenus Planorbella are 
in all respects like those of Pierosoma. 

The formulae of the different races are shown in the table below: 
Race Formula Locality 

campanulatum 20-1-20 to 22-1-22 Oneida Lake, New York 
c. wisconsinense 21-1-21 to 22-1-22 Muskelhinge L., Wisconsin 

c. wisconsinense 21-1-21 North Star Lake, Wisconsin 

c. canadense 21-1-21 to 23-1-23 Sturgeon L., Ontario 
c. canadense 21-1-21 to 23-1-23 Basswood R., Ontario 
c. smithi 26-1-26 Doughis L., Michigan 

Helisoma campanulatum wisconsinense w^as also studied anatomically 
from Lake Nipissing, Ontario. 

Geographical Distribution. Planorbella has been collected from Great 
Slave Lake, Labrador, Quebec, and Ontario south to New York, Ohio, and 
Illinois. Westward it extends to North Dakota and Nebraska. It is essen- 
tially a group of the northern part of the LTnited States and Canada. In 
this area it varies considerably and several races have been recognized. 
These appear to be mostly local races, not geographical, possibly environ- 
mental variations. 

Species Considered as Valid. The following species and races are 
recognized: 

Helisoma (Planorbella) campanulatum Helisoma (Planorbella) campanulatum 

campanulatum (Say) michiganense F. C. Baker 

Helisoma (Planorbella) campanulatum Helisoma (Plane/rbclla) campanulatum 

wisconsinense (Winslow) rudentis (Dall) 

Helisoma (Planorbella) campanulatum Helisoma (Planorbella) campanulatum 

davisi (Winslow) smithi (F. C. Baker) 

Helisoma (Planorbella) campanulatum Helisoma (Planorbella) multivolvis 

canadense F. C. Baker (Case) 

Helisoma (Planorbella) campamdatum 

collinsi F. C. Baker 

Geological Distribution. Pleistocene to Recent fauna. 

Remarks. Except for the campanulate aperture of the shell there is 
nothing in the anatomy to separate Planorbella from Pierosoma. The 
genitalia, with the long penial gland duct and the cup-shaped penial gland, 
the pseudobranch, and the kidney are all like these organs in Pierosoma. 
The radula is also the same. The shape of the shell, with its closely-coiled 
whorls and particularly the bell-shaped form of the aperture, may be 
features characteristic enough to retain Planorbella as a subgenus of 
Helisoma. 

H. Adams has erected the group Adula (preoccupied) to admit the very 
peculiar Planorbis multivolvis Case, a species living in Howe Lake, Mich- 
igan. As the race collinsi of Helisoma campamdatum approaches this 
species in the form of the shell, it would appear that the group name is 
without value in nomenclature. Lindholm (1927) coined a new name, 



154 The MoUuscan Family Plauorbidae 

Hypsogyra, in place of the preoccupied names Adula and Ancaeus. Should 
this species prove, after anatomical investigation, to have characteristics 
different from Planorhella, it should bear Lindholm's name. It is very rare 
and the animal is wholly unknown. It seems, from the features of the 
shell, perfectly safe to merge the group with Planorhella (see plate 80, 
figs. 19-21). 

Genus CARINIFEX W. G. Binney, 1863 

Type by original designation Planorbis newberryi Lea 

1863. Carinifcx Binney, Smith. Check-List of Shells. Type Planorbis newberryi Lea. 

As genus 

1864. Megasystropha Lea, Proc. Acad. Nat. Sci. Phil., p. 5 (footnote). Type Planorbis 

newberryi Lea. As genus 

1865. Carinijex Binney, L. and FW. Sh. N. A., II, p. 74. Type Carnijex newberryi 

(Lea). As genus 
1865. Carinifex, Amer. Jour. Conch., I, p. 50, plate vii, figs. 6-7 
1870. Megasystropha Tryon, Con. Hald. Mon., p. 84 
1870. Carinifex Tryon, Con. Hald. Mon., pp. 187, 214, Type Carinifex newberryi (Lea). 

As genus 
1870. Carinifex Dall, Ann. N. Y. Lye. Xat. Hist., IX, pp. 344, 353. Type Planorbis 

newberryi Lea. As genus 

1883. Carinifex Fischer, Man. de Conch., p. 508. Type Carinifex newberryi (Lea). 

As subgenus of Choanomphahis 

1884. Carinifex Tryon, S. and S. Conch., Ill, p. 105. Type Carinifex newberryi (Lea). 

As genus 

1912. Carinifex Hannibal, Proc. Mai. Soc. London, X, p. 162. Type Carinifex new- 
berryi (Lea). As subgenus of Pompholyx 

1918. Carinifex Walker, Miscel. Pub. Mus. Zool. Univ. Mich., Xo. 6, pp. 15, 106. 
Type Planorbis newberryi Lea. As genus 

1923. Carinifex Germain, Rec. Ind. Mus., XXI, p. 188. Type Carinifex newberryi 
(Lea). As genus 

1923. Carinifex Wenz, Fossil. Cat., Pars 22, p. 1671. Genotype Carinifex newberryi 

(Lea). As genus 

1924. Carinifex Dall. Prof. Pajiers U. S. Geol. Surv., Xo. 132 (G) ]). 112. As synonym 

of Megasystropha Lea 

1924. Megasystropha Dall, op. cit., p. 112. Type Planorbis newberryi Lea. As genus 

1925. Megasystropha Lea, Smith. Miscel. Coll., LXXIII, No. 3, Dec. 16. Opinion 87, 

Int. Com. on Zool. X'^omenclature 

1926. Carinifex Pilsbry, Science, LXIV, p. 248, Sept. 10. Defending use of this name 

instead of Megasystropha Lea 
1929. Carinifex J. Henderson, Univ. Col. Studies, XVII, No. 2, p. 143. Type Carinifex 

newberryi (Lea). As genus 
1929. Carinifex Chamberlin and Jones, Bull. Univ. Utah, XIX, No. 4, p. 155. Biol. 

Series I, No. 1. Genotype Planorbis newberryi Lea. As genus. 
1931. Carinifex Thiele, Handbuch, Teil 2, p. 480. Type Carinifex newberryi (Lea). 

As genus 

1934. Carinifex Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 48. Type Planorbis new- 

berryi Lea. As genus. Figures genitalia of Carinifex ponsonbyi and C. 
newberryi subrotunda 

1935. Carinifex J. Henderson, Non-Marine Moll. N. A., p. 255. Discussion of genus 

and listing of fossil species C. malheurensis Henderson and Rodeck 

Shell (plate 78, figs. 23-25). Medium to large, ultradextral, body whorl 
angulated; spire depressed or elevated, the whorls terraced and angular; 
base funicular; last whorl broad at the periphery, rapidly attenuated 
below; aperture triangular, outer lip thin; inner lip with slight callus. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 155 

When the spire of Carinife.v becomes elongated the shell is dextral although 
anatomically the animal is sinistral like that of Hclisomn. 

Animal. Resembling Helisoma in general form, but the tentacles are 
shorter (see plate 34, fig. 1). 

ANATOMICAL CHARACTERISTICS 
PLATE 34 {Carinijcx ponsorihyi E. A. Smith) 

GENITALIA. Male Organs (fig. 4). Seminal vesicle (SV) represented 
by many short vesicles bordering the ovisperm duct for a length of 4.5 mm. 
Sperm duct (SPD) long and narrow (2.5 mm. long), diminishing to less 
than half its diameter as it joins the vas deferens, which is a tube of fine 
diameter, 14-15 mm. long. The prostate (PRS) is elongated (3.5 mm. 
long). A section, through the prostate and uterus (fig. 7) shows that the 
]:)rostate is peculiar in having the diverticula (14 in this section) occurring 
laterally from a main pouch into which they empty and which, in turn, 
empties into the sperm duct. There appears to be no special prostate duct 
at each end, as in Helisoma. A section through the upper end of the prostate 
(fig. 8) shows only 11 diverticula but the arrangement is the same. 

Penial complex (fig. 2). The preputium (PR) is elongated and sac-like, 
4.5 mm. long and about 1 mm. wide at its greatest diameter. The vergic 
sac (VS) is short (1.5 mm. in length) and there is no marked constriction 
between the two sacs, as in Pierosoma. The musculature is different from 
that feature in Helisoma. There are two sets of retractor muscles (RM), 
one set, composed of two main branches with several small branches, is 
attached to the vergic sac and the upper part of the preputium; the other 
set, composed of two or more branching divisions, is attached to the upper 
part of the vergic sac, with one branch connecting with a branch of the 
first set. The vas deferens passes under this branch. There are three sets 
of supporting muscles (S]\I) attached to the preputium. These are divided 
several times in their attachment to tlie preputium and to the roof of 
the mantle cavity. Several small muscles appear on the base of the 
preputium below the first set of retractor muscles. 

Another specimen of ponsonbyi (plate 35, fig. 1) had a variation of 
this musculature, there being but one main retractor in the first set, and 
several narrow muscles, much branched, in the second set. The supporting 
muscles (SINI) were also somewhat different. All specimens have a very 
short (about 0.5 mm. long) penial gland duct on the outside of the penial 
complex between the vergic sac and the preputium (DC). This duct does 
not vary in any of the specimens examined. 

Internally (plate 34, fig. 3) , there are two fleshy pilasters in the 
preputium (PL). These are shown in section in fig. 12. The penial gland 
(01^) is an elongated, somewhat pyriform sac, narrowed at its junction 
with the body wall of the preputium and enlarged at the cup-shaped cavity. 
A section of the gland (fig. 10) shows many vertical glandular folds on the 
wall of the cup and a number of pavement-like folds in the bottom of the 
cup (IC). The gland duct (DC) extends into the cup and connects with 
the vertical and pavement-like folds. The verge (V) is short and thick. 
There is a muscular ridge or diaphragm (D) separating the cavity of the 
vergic sac from the preputial cavity. 

Female Organs. The spermatheca (S) is about 1 mm. long, long-ovate 
in shape and has a narrow duct (SD) almost 2 mm. in length, which enters 



156 The MoUuscan Family Planorbidae 

the short vagina (VG) without marked swelling. Another form of sperma- 
theca and duct, from another specimen, is shown in fig. 11. The uterus (U) 
is tough and leathery, long and wide (6 mm. long and 1 mm. wide), and is 
covered with wart-like prominences. The nidamental gland (NG) is wide 
and somewhat globular, covered with small follicles. The oviduct (OD) 
is much narrower than the uterus and is about 3 mm. long and 0.3 mm. 
wide. There is a large, swollen carrefour (OF). The relationship of the 
organs near the junction with the ovisperm duct is shown in fig. 6. The 
albumen gland (fig. 5) is about twice as long as wide and lies crosswise of 
the body. The space for the passage of the intestine is shown near the 
center of the figure. 

Hermaphrodite Organs (fig. 4). The ovotestis (OT) is composed of 
large club-shai)ed diverticula. A section of this organ near the front end is 
shown in fig. 9. Six rows of diverticula of varying length are to be seen. The 
sections vary in different parts of the ovotestis. There may be only six un- 
branched diverticula of large size, or there may be six or seven main 
branches, each branch subdivided two or three times to form a surface 
aspect of fourteen, fifteen, or eighteen diverticula. The free ovisperm duct 
(SO) is very short and appears only between the oviduct and the seminal 
vesicle. 

In another species, Carinifcx jacksoneiisis (plate 35, fig. 5), there is 
some deviation from the structures as seen in ponsonbyi. The seminal 
vesicle (SV) forms a grape-like bunching just beyond the ovotestis (about 
1 mm. long and 0.7 mm. wide) with lateral vesicles on the ovisperm duct 
as in ponsonbyi, and for the succeeding 2 mm. with very small vesicles 
which ap])ear as fine crenulations on one side only. The prostate (PRS) is 
shorter (only 3 mm. long) and is connected with the sperm duct in the same 
manner as in ponsonbyi. The diverticula are of the same form and condi- 
tion as in ponsonbyi. The spermatheca and its duct are also of about the 
same form (see fig. 9). In figs. 6 and 7, the features near the junction of 
the ovisperm duct are shown. There is a large carrefour (CF). The albumen 
gland (fig. 8) is relatively shorter than in ponsonbyi. 

The penial gland is of the same form as in ponsonbyi (fig. 3) and has 
the same short gland duct. The retractor muscles (RM), however, are 
much more complicated in form and position. They are much smaller, nar- 
rower, and more numerous. The supjiorting muscles (SM) are small and 
numerous and are attached to both vergic sac and preputium. Small 
muscles on the retractor muscle side of the preputium and on its lower half, 
are attached to the wall of the mantle cavity. These are believed to be 
supporting muscles. The attachment of the retractor muscles to the vergic 
sac is shown in fig. 2, which is the reverse of fig. 3. 

Pilsbry (1934, p. 50) figured the genitalia of Carinife.v ponsonbyi differ- 
ing in some respects from the drawings on plate 34. The musculature is 
nearly the same but is not shown in as great detail as in the figures on 
plate 34. The spermatheca is more nearly spherical in Pilsbry's figure. The 
seminal vesicle is shown as a mass of small vesicles, much as seen in 
Carinifex jacksonensis on plate 35 (fig. 5). The penial complex and penial 
gland in C. newberryi siibrotunda are figured. It is probable that the sex 
organs vary somewhat in form, especially those that are evertible. Also, 
the condition of the preserved material will make a great difference, espe- 



Suhjamilies, Genera, and Subgenera — Recent and Fossil 157 

cially in those organs like the nidamental gland, the uterus and the oviduct, 
which may become swollen and thus alter the true form of these organs. 

Three species of Carinijex have been dissected by Pilsbry and the 
writer, ponsonbyi, jacksonensis, and newberryi subrotunda, and all show 
the homogeneity of the group and its distinctness from Helisoma. 

Respiratory and Renal Systems. The pseudobranch (plate 34. fig. 1) 
of ponsonbyi is a rounded extension from the rectal region, in form like that 
in Helisoma, including the rectal ridge which extends over the pseudo- 
branch. In jacksonensis (plate 35, fig. 4), the pseudobranch is narrower. 
In the specimen figured, the pseudobranch was folded in such a manner as 
to make the ridge appear on the left margin of the organ. 

The kidney (plate 45, fig. 2) is long and narrow (15 mm. long, 1 to 1.2 
mm. wide) and the ureter is reflexed at right angles to the kidney. A sec- 
tion of the kidney near the middle (fig. 12) shows it to be much flattened, 
with a bottle-shaped lumen and roundly elongated, and flattened veins. 
There is no superposed ridge like that in Helisoma. The ridge on the mantle 
to the left of the kidney is seen in the section to be flattened and wide. 

Digestive System. The digestive system is similar to that of Pierosoma. 
The stomach region is shown on plate 48, fig. 3. The intestine is looped 
about the stomach and liver. The buccal sac is similar to that organ in 
Helisoma. 

The jaw is peculiar. There is but one jaw which is horseshoe-shaped, 
narrow, composed of many small, vertical plates which produce a saw-like 
edge. In ponsonbyi (plate 49, fig. 19), there are spiral striae on the jaw 
plates. In jacksonensis this striation is not visible (plate 49, fig. 18). The 
jaAV is attached to a very large cartilage which has the relative shape and 
size shown in fig. 17. In fig. 19, the jaw is somewhat distorted. The jaw of 
Carinijex bears some resemblance to the fragmented jaw of the Planor- 
binae, but the general form is different. 

Radula. The radula of Carinijex ponsonbyi (plate 67, fig. 8) has a 
square, bicuspid center tooth, the spade-shaped cusps extending below the 
lower border of the base of attachment. The lateral teeth (1-6) are tri- 
cuspid, all cusps sharply spade-shaped, including the mesocone. In some 
rows, single cusps may become bifid, as the ectocone in the fifth lateral 
tooth in fig. 8. The intermediate teeth (7-8) differ only in the splitting of 
the ectocone into two sharp cusps. The marginal teeth (9-27) are long and 
narrow, the entocone remaining unchanged at first (9-10) but the 
ectocone undergoing additional splitting. On the eleventh tooth the ento- 
cone begins to split, developing three small, sharp cus})s. In the outer 
part of the membrane, the marginal teeth become narrower and the ento- 
cone splits into seven very small, sharp cusps and the ectoconic area 
becomes simply serrated along the outer margin. The mesocone remains 
unchanged throughout the entire row. 

In Carinijex jacksonensis (plate 65, fig. 4), the teeth have practically 
the same shape, but are smaller. There are ten lateral teeth and two 
intermediate teeth. In the splitting of the marginal teeth, the inner cusp 
of the entocone is larger than the four cusps on the inner side of the 
mesocone. This feature persists throughout the radula. Tlic radula formulae 
of the two species are as follows: 

ponsonbyi 32-1-32 Klamath Lake, Oregon 210-217 J. Henderson 

jacksoijensis 25-1-2.5 Jackson Lake, AVyoming 215-221 J, Henderson 



158 The Molluscan Family Planorhidae 

The data for the specimens examined are as follows: ponsonbiji, from 
lower end of Upper Klamath Lake, Klamath Falls, Oregon, collected by 
Mr. and Mrs. J. Henderson, August 7, 1931; ten specimens dissected. 
Jacksonensis, from Jackson Lake, at Moran, Wyoming, in shallow water 
just above dam at very low water stage, collected by Mr. and Mrs. 
Henderson, August 20, 1931; eight specimens dissected. 

Geographical Distribution. Carinife.v is a purely American group 
found only in western America from California eastward to Wyoming. 
Pilsbry believes that all of the described species and races of Carinifex 
are subspecies of a single stock comparable to the subspecies of Helisoma 
anceps (Menke). There are, indeed, comparable characteristics between 
these two groups, although the anceps group is much more widely dis- 
tributed, both in latitude and area, and is subject to more diverse cnvii'on- 
mental influences than is Carinife.v. 

Species Considered as Valid. A careful study of all sj^ecics, many 
specimens from the type lots, leads the writer to the following conclusion 
concerning the specific range of the genus. There are doubtless anatomical 
characteristics which separate some of the s))ecies as has been noted 
in ponsoiibiji and jacksonensis. 

■Carinifex newberryi newherryi (Lea) Carinifex occidentalis Hanna 

Carinifex newberryi minor Cooper Carinifex ponsonbyi E. A. Smith 

Carinifex newberryi malleata Pilsbry Carinifex jacksonensis J. Henderson 
Carinifex neivberryi subrotunda Pilsbry 

Geological Distribution. Pliocene to Recent fauna. The genus may 
extend as far back as the Miocene period. 

Remarks. Carinifex has been thought to be closely allied to Helixoma 
and Pilsbry states (1934, p. 48) that there is very little structural difference 
between the two groujis. There are, however, characteristics of both shell 
and anatomy which, in the judgment of the writer, are sufficient to mark 
Carinifex as of generic rank. The ultradextral shell bears some resem- 
blance to certain forms of typical Helisoma but the anatomy, especially 
the genitalia, exhibits features of importance. The external penial gland 
duct is shorter than in any form of Helisoma and is of different form. The 
prostate, when seen in section, shows the diverticula to be formed in a 
totally different manner from those of Helisoma. The musculature of 
the penial complex is far more comjilex with two distinct retractor muscles. 
The jaw is also of entirely different shape and nature. The radula teeth 
have the mesocone as it is in typical Helisoma. The kidney is wdthout a 
superposed ridge. 

By a ruling of the Liternational Commission on Zoological Nomen- 
clature (Opinion 87), the name Carinifex of W. G. Binney has been ruled 
out of systematic nomenclature because of its publication in what is termed 
a '])roof sheet' and therefore not usable as a nomenclatorial reference. 
Proof sheets are obviously not to be quoted as systematic references to 
publication, but the example chosen to sustain this ruling was most un- 
fortunate, since the publication in which the name Carinifex appeared 
(Smithsonian Miscellaneous Collections), is an octavo pamphlet of twelve 
leaves, printed on one side (the left) for corrections. This pamphlet was 
widely distributed among conchologists and is even now available among 
secondhand book dealers. The contention that this pamphlet is merely a 



Subfamilies, Genera, and Subgenera — Recent and Fossil 159 

'proof sheet' seems unwarranted and the writer fully agrees with Pilsbry 
( 1926, p. 248) that Carinifex was sufficiently 'published' by Binney 
and that this name should be used in place of Megasystropha Lea, which is 
ruled by the Commission to be used instead of Carinifex. 

Dall (1870) says (in footnote under Carinifex) 'Megasystropha Lea. 
Neither genus was characterized by the author, and the former is in gen- 
eral use and has priority.' In 1924, however, Dall reversed this opinion 
(Prof. Papers, p. 112) and used Megasystropha as the name for this 
group, contending that the earlier 'proof sheets' of 1863 were simply proofs 
and should not be quoted. However, in a general review of the literature 
of this genus, it is evident that the name Carinifex has been almost 
universally used, as noted in the bibliography of the genus on a previous 
page of this volume. Henderson (1929, p. 143) well states the situation in 
the following words. 'It must not be forgotten that the purpose of rules 
of nomenclature is to insure, so far as possible, stability of names and 
certainty in their use in the designation of species,- etc., wdiich purpose 
would be defeated rather than accomplished by this proposed substitution.' 
The name Carinifex is, therefore, adopted in this work. 

Genus VORTICIFEX Meek, 1870 

Type by original designation Carinifex tnjoni Meek 

1870. Vortifex Meek, Proc. Acad. Nat. Sci. Phil., p. 59. Type Carinifex (Vortifex) 
tryoni Meek, new species. Proposed as subgenus of Carinifex Binney 

1870. Vorticifex Dall, Ann. N. Y. Lye. Nat. Hist., IX, p. 353. Correction of Vortifex, 

originally misspelled. Type Carinifex tryoni Meek. 

1871. Vorticifex Meek, Tryon, Amer. Jour. Conch., VI, p. 285, April, 1871. Review 

of Meek's paper. Vortifex corrected to Vorticifex and Carinifex tryoni stated 
to be the type 
1877. Vorticifex Meek, U. S. Geol. Surv. 40th Parallel, IV, p. 187. Subgenus described 
and Carinifex binneyi and tryoni both placed therein 

1883. Vorticifex Fischer, Man. de Conch., p. 508. Type Carinifex tryoni Meek. As 

subgenus of Carinifex 

1884. Vorticifex Tryon, S. and S. Conch., Ill, p. 105. Type wrongly stated to be 

Carinifex binneyi Meek. As subgenus of Carinifex 
1888. Vorticifex C.^ll, Amer. Geol., I, p. 148. Genus formally described and Carinifex 

binneyi Meek wrongly designated as type 
1922. Vorticifex Hann.\, Univ. Oregon Pub., I, No. 12, p. 7. Type Carinifex tryoni 

Meek. As genus 
1924. Paradines Dall, U. S. G. S., Prof. Papers, No. 132, p. 112. Type by original 

designation Carinifex binneyi Meek. As section of genus Megasystropha 
1935. Vorticifex Henderson, Fossil Non-Marine Moll. N. A., p. 255. Type Carinifex 

tryoni Meek. As genus 

Shell (plate 76, fig. 12 tryoni; fig. 13, binneyi). Large, ultradextral, of 
few rapidly enlarging, rounded whorls, the body whorl very large, rounded, 
and sculptured with distinct, rib-like striae parallel with the lines of 
growth; right side flatly convex; left side with deep 'umbilical' dej^'ession 
almost completely obscuring the inner whorls; aperture large, rounded. 

'The chief distinguishing features of the genus are (1), lack of carinae, 
either at periphery, suture or around umbilicus; (2), much rounder body 
whorl than Carinifex; and (3), much less triangular aperture than 
Carinifex' (Hanna, 1922, p. 7) . 



160 The Molluscau Family Planorhidae 

Geological Horizon and Distribution. Eocene, Triickee Lake beds, 
Nevadci; Payette Lake beds, Idaho; Fossil Hill, Kawsoh Mts., Nevada; 
Pliocene, Cache Valley, Mendon, Collinston, Utah; Tulare formation, 
Kettleman Hills, California; Warner Lake beds, eastern Oregon. A single 
species, Vorticifex stearnsii (White) has been reported from the INlorrison 
formation in Wyoming, belonging in the upper Jurassic or Lower Creta- 
ceous period. 

Species Considered as Valid. The following species and races have 
been referred to this genus. 

Vorticifex tryoni (Meek) Vorticifex binneyi (Meek) 

Vorticifex tryoni concava (Meek) Vorticifex stearnsii (White) 

Vorticifex tryoni ventricosa (Meek) 

Remarks. Vorticifex appears to be a rather distinct genus related to 
both Carinifex and Parapholyx. Tlie wide body-whorl with its distinct 
costae is ciuite characteristic. The name Paradines Dall (1924, p. 112) 
founded upon the larger species Carinifex binneyi IVIeek does not appear 
more than specifically distinct from the smaller Carinifex tryoni Meek. 
Both species seem, from the published figures, to be generically closely 
related and to be distinct from the genus Carinifex. 

Several species referred to "Vorticifex appear to belong elsewhere. 
Vorticifex sanctaeclarae Hannibal and V. sanctaeclarae marshalli Arnold 
seem rather to belong in Carinifex as originally described rather than in 
Vorticifex as listed by Henderson (1935, p. 257). They were placed in 
Carinifex by Pilsbry (1934, p. 567). Tlie Vorticifex laxus of Chamberlin 
and Berry (Nautilus, XLVH, p. 26, 1933) does not appear to fit into the 
genus Vorticifex, but might be included in the genus Carinifex. It appears 
to be an internal cast and the external characteristics would not show 
clearly in such a condition. 

Genus PERRINILLA Hannibal, 1912 
Type by original designation Helisoma cordillerana Hannibal 

1912. Perrinilla Hannibal, Proc. Mai. Soc. London, X, p. 159. Type Helisoma cordil- 
lerana Hannibal. As subgenus of Helisoma 

1923. Perrinilla Wenz, Fossil. Cat., Pars 22, p. 1518. Genotype Planorhina (Perrinilla) 
cordillerana (Hannibal). As subgenus of Planorhina Haldeman 

1934. Perrinilla Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 48. Type Helisoma cordil- 

lerana Hannibal. Presumably considered as genus 

1935. Perrinilla J. Henderson, Fossil Non-Marine Moll, of N. A., p. 246. Type 

Helisoma cordillerana Hannibal 

Shell (plate 79, figs. 31-32). 'Similar to Planorbella, except that it is 
totally ultra-sinistral; spire-jiit deep and narrow, umbilicus but slightly 
excavated, superior and inferior peripheries subangular' (Hannibal for 
subgenus). 

'Shell of considerable size, whorls large, somewhat compressed, and 
strongly ultrasinistral, the umbilicus barely concave, superior and in- 
ferior periplicries subangular in young stages, becoming rounded in adult, 
growth striae strong, spiral striae occasionally preserved, aperture ex- 
panded somewhat in adult; habitat apparently lacustrine. Diameter 22, 
alt. 9, diameter of aperture 12 mm.' (Hannibal, p. 161, description of 
Helisoma cordillerana) . 



Subjaniilies, Genera, and Subgenera — Recent and Fossil 161 

Geological Horizon and Distribution. Eocene period. Truckee Lake 
beds, Nevada, several localities. Miocene. Contra Costa Lake beds, Cali- 
fornia, Planorbis pablocinus J. G. Cooper, 1894, is believed by Hannibal 
to be congeneric. 

Species Considered as Valid. Perrinilla cordillerana (Hannibal), the 
genotype, is the only recognized species of the genus. 

Remarks. PerriniUa appears to be more closely related to Carinifex 
than to Helisoma, as suggested by Pilsbry (1934, p. 49), who says 

Perrinilla Hannibal, 1912 .... seems to stand near the form of the Carinifex phylum 
to be expected in the Eocene, and it maj' possibly belontj in the ancestral line of 
Carinifex. 

The best disposition of the group in planorbid classification appears to be 
as a distinct genus near Carinifex. 

Genus PARAPHOLYX Hanna, 1922 
T3-pe by original designation Pompholyx efjusa Lea 

1856. Pompholyx Lea, Proc. Acad. Nat. Sci. Phil., VIII, p. 80. Type Pompholyx 

efjusa Lea. Not Pompholyx Goose, 1851, Rotifera. As genus 

1857. Pompholyx Le.\, Journ. de Conch., VI, p. 208. As genus 

1865. Pompholyx W. G. Binxey, L. and FW. Sh. N. A., 11, p. 73. Type Pompholyx 

efjusa Lea. As genus 

1866. Pompholyx Dall, Proc. Cal. Acad. Sci., Ill, pp. 265, 268. De.scription of sub- 

family Pompholiginae 
1868. Pompholyx J. E. Gr.\y, Ann. Mag. Nat. Hist., (4) II, p. 387. As genus 
1870. Pompholyx Dall, Ann. N. Y. Lye. Nat. Hist., IX, pp. 334, 344, 353. Type 

Pompholyx efjusa Lea. As genus. Anatomy imperfectly described 
1870. Pompholyx Tryon, Con. Hald. Mon., pp. 83, 174. Type Pompholyx efjusa Lea. 

As genus 

1883. Pompholyx Fischer, Man. de. Conch., 507. Type Pompholyx efjusa Lea. As 

genus 

1884. Pompholyx Tryox, S. and S. Conch., Ill, p. 105. Tj'pe Pompholyx efjusa Lea. 

As genus 
1886. Pompholyx Clessix, Conch. Cab., XVII, p. 226. Type Pompholyx efjusa Lea. 

As genus 
1912. Pompholyx Haxxibal, Proc. Mai. Soc. London, X, p. 162. Type Pompholyx 

efjusa Lea. As genus 
1918. Pompholyx Walker, Miscel. Pub. Mus. Zool., Univ. Mich., No. 6, pp. 14, 105. 

Type Pompholyx efjusa Lea. As genvis 
1922. Pompholyx Germaix, Rec. Ind. Mus., XXI, p. 185. Type Pompholyx efjusa 

Lea. As genus 
1922. Parapholyx Hanxa, Univ. Oregon Pub., I, No. 12, p. 5. New name for Pom- 
pholyx Lea, 1856, non Goose, 1851 
1927. Pompholycodea Lixdholm, Proc. Commission for study of Lake Baikal, II, 

p. 180. New name for Pompholyx Lea. not Goose 
1929. Parapholyx J. Hexdersox, Univ. Col. Studies, XVII, No. 2, p. 145. Type 

Pompholyx efjusa Lea. As genus 
1931. Pompholycodea Thiele, Handbuch, Teil 2, p. 480. Type Pompholyx efjusa Lea. 

As genus 

1934. Parapholyx Pil.sbry. Proc. Acad. Nat. Sci. Phil., 86. pp. 46, 51. Type Pompholyx 

efjusa Lea. As genus 

1935. Parapholyx J. Hexder.sox, Fossil Non-Marine Moll. N. A., p. 254. As genus 

1936. Parapholyx F. C. Baker, Nautilus, L, pp. 30-31. Notes on anatomy 



162 The Molluscan Family Planorbidae 

Shell (plate 78, figs. 20-22). Of medium size, ultradextral, globose, the 
spire short and but little raised above the body whorl which is ventricose 
and embraces most of the shell; aperture wide, greatly expanded; outer 
lip thin, acute, somewhat reflexed in adult or old specimens; inner lip more 
or less thickened; base convex or conical, imperforate or with but a small 
chink. 

Animal (plate 36, fig. 1). Foot short, about half as broad as long. 
Velum as in Helisoma. Tentacles short, cylindrical, blunt at the end, not 
tapering. Eyes sessile at the inner base of the tentacles. The eyes are not 
conspicuous in some preserved specimens. The body is darkly pigmented, 
the pigmented areas extending to the head and sometimes forming streaks 
on the tentacles. The posterior portion of the body is light gray. The ovo- 
testis area is yellowish. 

ANATOMICAL CHARACTERISTICS 
PLATE 36 {P(imi>hohjx cffuM, klamnthcnsis F. C. Baker) 

GENITALIA. Male Organs (fig. 3). Seminal vesicle (SV) about 4 
mm. long, swollen, with many small vesicles projecting from the other- 
wise smooth surface. The sju^rm duct (SPD) is about 3 mm. long and of 
large diameter (0.4 mm. L The prostate (PRS) is long (3.5 mm.) and wide 
and is composed of many small diverticula. In section (fig. 4), these di- 
verticula are seen to be composed of about a dozen irregular follicles linked 
together like sausages. From the outside of the prostate, these diverticula 
appear to be covered with small tubercles irregularly placed. These follicles 
enter the sperm duct at a common center, shown at X in the figure. The 
vas deferens is about half the diameter of the sperm duct and is 11 mm. 
long. 

The penial complex (fig. 7) is sac-like and is nearly 4 mm. in length. 
The preputium is 1 mm. wide and occupies most of the length of the 
penial complex. The vergic sac (VS) is 1 mm. long and 0.7 mm. wide. There 
is only a slight constriction between the prejiutium and the vergic sac. 
The penial gland duct is relatively short (about 1.5 mm. long) and rather 
thick. It extends from the i)reputium near its upper third and enters the 
vergic sac at the constricted area. The portion of the duct entering the 
vergic sac and the preputium is very small and narrow, the duct swelling 
greatly in diameter on the surface of the preputium. There are two sets 
of retractor muscles, each set consisting of two main branches which sub- 
divide several times at the penial sac insertions and at the connections 
in the columella muscle. All insertions are on the preputium, none on the 
vergic sac. There are several narrow supporting muscles (SAI) attached 
to the preputium. 

Internally (fig. 9) , the preputium has two large, fleshy folds or pilasters 
(PL). There is a mucii elongated, cylindrical penial gland (1.7 mm. long) 
which resembles a pipe-stem, with a cup-shaped or bowl-shaped gland 
(about 0.5 mm. in diameter) placed at the lower end (GL). The duct 
(DC and X) enters the cylindrical portion of the gland and extends 
through this stem-like portion, then enters the bowl-like cup of the gland 
where it is enlarged into a bulb-like body (fig. 11, X). The cup-shaped 
gland resembles the bowl of a pipe. In section (fig. 11), the cup shows a 
shallow area at the top and the sides are lined with wide, thick folds (GF). 
The bottom of the bowl-like cup is covered with small follicles which are 



Suhfamilies, Genera, and Subgenera — Recent and Fossil 163 

placed at the upper end of the rounded enlargement of the penial gland 
duct. The right pilaster is attached to the gland at its upper end, curving 
toward the gland beneath the gland duct. 

There is a thick ring or diaphragm (D) which separates the cavity 
of the preputium from the vergic cavity. This diaphragm has a circular 
canal into which the upper end of the penial gland duct, which is greatly 
diminished in diameter, enters. This feature is shown in fig. 10. The verge 
(V) is narrowly pyriform, tapering to a point at its lower end. The sperm 
canal extends through the center of the verge and has a central outlet 
(fig. 121. A large nerve and blood vessel supply the penial complex (fig. 8). 

Female Organs (fig. 3). The spermatheca (S) is large and egg-shaped, 
almost globular. It is connected with the short, narrow vagina (VG) by 
a narrow duct shorter than the length of the spermatheca (SD). The 
uterus (U) is narrow as it passes upward from the vagina but increases 
abruptly in diameter to three times the width of that region, combining 
with the nidamental gland. This region is concealed by the prostate in 
fig. 3. The oviduct (OD) contracts in diameter to form a sac-like organ 
of small diameter. There is a large carrefour (CF). The albumen gland 
(AD is 4 mm. long and is longer than wide. The duct of this gland is 
long (0.5 mm.). 

Hermaphrodite Organs. The ovotestis (OT) is long and sac-like and 
is composed of several club-shaped diverticula. A section near the middle of 
the ovotestis (fig. 5) shows eight rather long diverticula, the longest follicles 
being in the center. A section near the posterior end (fig. 6) shows six 
diverticula in less fan-like pattern. Sections from the middle to the anterior 
end show eight diverticula all in fan-shaped pattern, but sections made 
toward the posterior end show but six diverticula which are more or less 
irregularly arranged. The ovisperm duct is very short in the portion be- 
tween the ovotestis and the seminal vesicle. The free portion near the 
oviduct is somewhat longer. The seminal vesicle (SV) occupies about two- 
thirds of the length of the ovisperm duct. 

The genitalia of Parapholijx effusa diagonaUs Henderson, also dis- 
sected, do not differ from the figures and descriptions herein presented. 

In 1870, Dall dissected Pompholyx soUda and published descrii-)tions 
and several figures of the genitalia. These are not in sufficient detail and 
embrace some errors, such as the presence of a distinct testicle on the male 
system. This might have been the albumen gland. As far as can be seen, 
the anatomy of solida is similar to that of the species personally examined 
and herein figured. 

Respiratory and Renal Systems. The pseudobranch (fig. 2) is a tri- 
angular appendage extending from the rectal region. There is a distinct 
ridge extending over the rectum in a broad curve, ending above the anus. 

The kidney (plate 46, fig. 1) is short and wide (about 3 mm. long and 
1 mm. wide) ; the ureter is large and sharply refiexed. directed upward into 
the mantle cavity. The pericardium is also large (about 1 mm. long). A 
cross section of the kidney near the middle (fig. 2) shows a much flattened 
form with a wide lumen, the veins ovate and flattened, and placed at the 
lower lateral sides of the lumen. There is no ridge and the section re- 
sembles that of Carinifex. 

Digestive System. The stomach is like that of Carinifex and essen- 
tially as described by Dall for Pompholyx solida. The oesophagus is short 



164 The Molluscan Family Planorhidae 

and is enlarged just behind the buccal sac. The salivary glands form a 
loop. The buccal sac is short, high and pyriform, as in Carinifex. 

The jaws are three in number, differing markedly from the single horse- 
shoe-shaped jaw of Carinifex. The superior jaw is low and about three 
times as wide as high. The side jaws are as in Helisoma. The face of the 
superior jaw is striated vertically. There is little difference between the 
jaws of klamathensis and diagonalis. Dall says there are no accessory 
plates (side jaws) but they occurred in all specimens personally examined. 
The jaw figured by Dall (his plate 2, fig. 11a) is different from the jaws 
found in the two races examined. 

The radula of P. effusa klniitathoi.'iis (plate 65, fig. 3) has a squarish 
center tooth, the bicuspid reflection not reaching the lower margin of the 
base of attachment. The lateral teeth (1-8) are scjuarish and tricusi)id, all 
cusps being sharp and spade-shaped. The intermediate teeth (9-11) are 
narrow, the ectocone splitting into two sharp cusps as long as, or nearly 
as long as, the mesocone. There are two small cusps on the outer border 
of the tooth, above the ectocone. The marginal teeth (13-15) are narrow, 
the entocone with four to five small cusps, the ectoconic region with three 
cusps. The outer marginal teeth (16-19) are very narrow and are simply 
serrated on the ectoconic side, there being no division into entocone, meso- 
cone, and ectocone. Ball's figure of the radula of solida (his plate 2, fig. 9) 
shows the lateral teeth with a rounded mesocone and all cusps appear too 
blunt. The marginal teeth are too wide and the small cus])s are not shown. 

Radula Formulae of Paraphnhjx 

Species Formula Locality Roirs Collector 

klamathensis 19-1-19 Klamath Lake, Oregon 125 J. Henderson 

diagojialis 21-1-21 Crater Lake, Oregon 100-114 J. Henderson 

solida 22-1-22 White Pine, Nevada 150 Ball's paper 

The following material has been examined for the anatomical data 
contained in this work. P. effusa klamathensis from outlet of Upper 
Klamath Lake, Oregon, eight si)ecimens examined. P. effusa diagonalis from 
Crater Lake, Oregon, eight specimens examined. Both lots collected by 
J. Henderson. 

Geographical Distribution. Parapholyx is purely an American genus 
confined to the west coast of America from Washington southward to Cali- 
fornia and eastward to Nevada. Pompholyx leana H. and A. Adams was 
described from 'West Columbia,' but no specimen of this genus has been 
seen from British Columbia and it is very doubtful that the genus is found 
north of the United States. A number of species and races have been 
described and the same opinion expressed for the division of Carinifex may 
also ap]^ly to this genus. 

Species Considered as Valid. 

Parapholyx ejjusa effusa (Lea) Parapholyx nevadensis J. Henderson 

Parapholyx ejjusa coHata (Hemphill) Parapholyx mailliardi Hanna 

Parapholyx ejfusa diagonalis Parapholyx solida solida (Dall) 

J. Henderson Parapholyx solida optima (Pilsbry) 

Parapholyx ejfusa klamathensis F. C. Parapholyx leana (H. and A. Adams) 

Baker Species practically unknown 

Geological Distribution. Parapholyx is certainly known from the 
Pliocene to the Recent fauna. It may occur in earlier deposits. One extinct 



Suhfaniilies, Genera, and Subgenera — Recent and Fossil 165 

species is known, Parapholy.v packardi Hanna, from Warner Lake deposits 
in eastern Oregon. 

Remarks. Parapholyx is a very distinct genus both in shell and anat- 
omy. The shell is depressed and almost neritaeform. The anatomy is pe- 
culiar in several respects. The prostate is not composed of distinct club- 
shaped diverticula, but of small gland-like bodies arranged like a string 
of sausages. The penial gland is not a short, cup-shaped organ, as in 
Carinifex, but an elongated, pipe-shaped body with a cup-like termination, 
with a long duct passing through the center of the longitudinal, sac-like 
'stem' of the gland. The termination of the duct is swollen and bulb-like, 
expanding in the bottom of the })enial gland cup. The penial gland duct 
is external as in Carinifex, but it is somewhat longer and of greater di- 
ameter. The jaw' is like that of Helisoma and is not fragmented like that 
of Carinifex. The genus stands out as one of the most distinct among 
American planorbids. 

In 1866, Dall instituted a subfamily Pompholiginae for Fomphoh/x 
effusa, basing the separation on the supposition that there were two pairs 
of eyes, one at the inner base of the tentacles and one at the end of the 
tentacles. The fact of this peculiar condition was positively stated by 
Mr. William ]\I. Gabb, who made drawings of the animal. Dr. J. E. Gray 
( 1868, p. 387) questioned this statement. In 1870, Dall obtained specimens 
of a Fompholyx iFarapholyx) different specifically from the known species, 
which he called solida. An examination of the tentacles of this species at 
once cleared up the anomaly of the four eyes, the supposed eyes on the 
end of the tentacles being simply an aggregation of pigment. Only one 
pair of eyes is present, at the inner base of the tentacles, as is the case in 
other species of Planorbidae. 

Dall still retained the subfamily Pompholiginae (1870, p. 352) although 
the chief reason for its adoption, the four eyes, had been found to be 
invalid. The subfamilv has been used bv most writers on fresh-water Mol- 
lusca, including Fischer (1883, p. 507), Trvon (1884, p. 105), Walker 
(1918, p. 14), Germain (1922, p. 185), Henderson (1929, p. 143), and 
Chamberlin and Jones (1929, p. 155). Hannibal (1912, p. 161) elevated 
it to family status as Pomplioligidae. Dall has also used the name Pompho- 
liginae for a section of the marine genus Divaricella (Proc. U. S. Nat. INIus., 
XXIII, p. 814, 1901). 

The study of the animals of Carinifex and Farapholyx shows that they 
have no general anatomical characteristics not shared by Helisoma and the 
subfamilv Pompholiginae must therefore be abandoned. This course was 
indicated by Pilsbry in 1934 (p. 46). In 1936 (Nautilus, L, p. 30), the 
writer indicated the general anatomical features of Farapholyx, showing its 
general relationship to Helisoma and Carinifex and stating that the old 
subfamily Pompholiginae was without anatomical distinction. 

Genus PO^^IPHOLOPSIS Call, 1888 
Type b}' original designation Pompholopsis tvhitei Call 

1888. Pompholopsis Call, Amer. Geol., I, No. 3, p. 147. Type Pompholopsis whitei 

Call. As genus 
1935. Pompholopsis J. Hexdersox, Fossil Xon-Marine Moll. N. A., p. 255. Type 

Pompholopsis ichitei Call. As genus 



166 The Molluscan Family Planorhidae 

Shell (plate 76, fig. 11). 'Dextral, globose, rather solid, deeply iimbili- 
cated; whorls three to three and one-half, convex, body-whorl very large; 
sjiire short, apex obtuse; aperture roundly ovate; peritreme continuous, 
forming a heavy callus on the parietal wall of the body-whorl. Grovrth 
lines inconspicuous, surface of the shell smooth; sutures rather irregularly 
impressed. Length 7.26 mm.; diameter 8.13 mm.' (Call, 1888, p. 147). 

Geological Horizon and Distribution. Post-pliocene (Pleistocene). 
Tassajara Lake beds, California. 

Species Considered as Valid. Ponipholopsis ivhitei Call is the only 
species assigned to this genus. 

Remarks. Pompholopsis differs from Parapholyx in being deeply um- 
bilicated and in having a high spire and smaller, rounder aperture. It is 
related to Parapholyx but appears sufficiently distinct to justify a genus. 
A scries of shells might add greatly to our knowledge of the relationship 
of this species. 

Genus PLANORBARIUS Froriep, 1806 
Type by original designation Helix cornea Linn. 

1806. Planorharius Froriep, in Dumeril, Analyt. ZooL, p. 165. Type Helix cornea Linn. 
As genus 

1810. Planorbis Moxtfort, Conch. Syst., H, p. 270. Type Planorbis corncus (Linn.). 
Non Geoffroy or Miiller. As genus 

1840. Planorbis Swainson, Treat. Malac, p. 337. Type Planorbis corncus (Linn.). 
As genus 

1847. CoreUis (Adanson, 1757) Gr.\y, Proc. Zool. Soc. London, p. 180. Type Pla- 
norbis Cornells (Linn.). As genus 

1850. Spirodiscus Stein, Schn. u. Muscheln Berlin, p. 73. Type (1st species) : Planor- 
bis corncus (Linn.) 

1855. Coretus Moquin-T.andon, Hist. Moll. Terr. Fluv. France, II, pp. 424, 445. Type 
Planorbis corneus (Linn.) 

1870. Planorbis Dall, Ann. N. Y. Lye. N. H., IX, p. 351. Type Planorbis corncus 
(Linn.). As genus 

1883. Spirodiscus Fischer, Man. de Conch., p. 509. Tyjie Helix corncus Linn. As 

section of Planorbis 

1884. Planorbis Tryon, S. and S. Conch., Ill, p. 106. Type Planorbis corncus (Linn.). 

As genus 

1885. Coretus We.sterlund, Fauna Pal. Reg., V, p. 64. No type cited. As subgenus 

of Planorbis 

1886. Coretus Clessin, Conch. Cab., XVII, p. 32. Type Planorbis corneus (Linn.). 

As subgenus 
1902. Spirodiscus Westerlund, Rad. Jugoslav. Akad., 151, p. 120. Type Helix cornea 

Linn. As subgenus 
1905. Planorbis Dall, Alaska Moll., p. 81. Type Planorbis corneus (Linn.). As genus 

1917. Planorbis Soos, Ann. Musei Nat. Hungarici, XV, pp. 37, 140. Type Planorbis 

corneus (Linn.) 

1918. Planorbis Walker, Miscel. Pub. Mus. Zool., Univ. Mich., No. 6, p. 94. Type 

Planorbis corneus (Linn.). As subgenus of Planorbis 
1921. Planorbis Germain, Rec. Ind. Mus., XXI, pp. 6, 9. Type Planorbis corneus 
(Linn.). As subgenus of Planorbis 

1923. Coretus (Gray 1847) Wenz, Fossil. Cat., Pars 22, p. 1421. Genotype Coretus 

corneus (Linn.). As genus 

1924. Planorbarius Kennard and Woodw.\rd, Proc. Mai. Soc. London, XVI, p. 10. Type 

Helix cornea Linn. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 167 

1926. Planorbiirius Kennard and Woodward, Syn. Brit. Non-Marine Moll., p. 67. Type 
Helix cornea Linn. As subgenus 

1926. Planorbis Lindholm, Archiv. fiir Mollusk., Heft 6, year 58, p. 252. Ideogenotype 

Helix cornea Linn. As genus, type by Montfort 

1927. Planorbis Pilsbry and Bequaert, Bull. Amer. Mus. N. H., LIII, pp. 115, 116. 

Type Planorbis corneus (Linn.). As genus 
1929. Coretus (Gray 1847) H.^As, Trab. Museo Cien. Nat. Barcelona, XIII, p. 378. 

Type evidently Helix cornea Linn. As genus 
1931. Planorbis F. C. Baker, Proc. Zool. Soc, London, p. 583. Genotype Helix cornea 

Linn. As genus 
1931. Coretus (Andanson, 1757) Germain, Moll. Terr. Fluv. France, II, p. 517. No 

type cited but Planorbis corneus (Linn.) described. As subgenus of Planorbis 
1931. Planorbis Thiele, Handbuch, Tcil 2, p. 479. Type Planorbis corneus (Linn.). 

Subgenus of Planorbis Miiller, 1774 

Shell (plate'80, figs. 22-24). Large, sinistral, discoidal, rather solid, of 
few gradually enlarging whorls, equally visible above and below; aper- 
ture slightly enlarged, in the same plane as the whorls; lips sharp, not 
thickened. 

Animal. With short, wide foot, rounded before, tapering behind, the 
vela area large; tentacles long, wide at the base, and tapering to a point, 
eyes sessile at their inner bases. Color of living animal lead, sometimes 
nearly black tinged with brown; tentacles bluish black. Sometimes the 
whole body is reddish. 

The young snail of two whorls, recently hatched from the egg capsule, 
is very translucent, the organs plainly visible through the hyaline shell. 
The body shows pinkish through the shell, head and foot with border of 
white on edge. The radula sac may be seen working backward and forward, 
when feeding, as in the adult animal. The heart may be observed beating 
rapidly. The young snails are distinctly physoid in form and glide about 
like Physa. Specimens of the young with bifid tentacles are not uncommon. 

ANATOMICAL CHARACTERISTICS 
PLATE 20 {Planorbarius corneus (Linn.) ) 

GENITALIA. Male Organs (fig. 13). The seminal vesicle (SV) is about 
4 mm. long and 1 nun. wide, narrowing at the anterior end to the diameter 
of the ovisperm duct. This organ is a rounded mass of small vesicles. A 
number of small vesicles continue down one side of the ovisperm duct. The 
sperm duct (SPD) is about 10 nnn. long. Where it leaves the ovisperm duct 
it is of small diameter, but it gradually enlarges to twice this diameter near 
the prostate where it abrui^tly expands to several times the first diameter, 
and then suddenly diminishes again to almost its original diameter. The 
prostate (PRS) is elongated and somewhat fan-shaped, 4.5 mm. long. The 
duct of the prostate is a continuation of the vas deferens and is about 
1 mm. long. It lies over the sperm duct with which it is connected, the 
prostate diverticula radiating from this duct. The vas deferens (VD) is 
a narrow tube about 12 mm. long. 

The prostate in section <fig. 4) is radiate or fan-shaped in form, the 
seven to nine main diverticula branching several times (usually lour) 
toward the outer part of the section. Figure 4 also shows the relationship 
between the uterus, the nidamental gland, and the prostate, the figure being 
a cross section cutting through these organs. The prostate diverticula may 
be noted to enter the prostate duct directly. 



168 The Molluscan Family Planorbidae 

The penial complex (fig. 12) consists of a very large, pyriform pre- 
putium (PR), 3.5 mm. long and 2 mm. wide at the upper part, tapering 
to 0.5 mm. wide at the male opening. The vergic sac (VS) is very small 
(about 1 mm. long) and is placed at the summit of the preputium, lying on 
that organ. There are two retractor muscles (RM), an upper one attached 
to the preimtium near the vergic sac by two branches, one branch on each 
side of the vergic sac, and a lower muscle attached at about midway of 
the preputium. There are four or five sui)porting nuiscles (SM) on the 
opposite side from the lower retractor muscle. In some specimens, the two 
retractor muscles are placed one above the other attached to the preputium 
near the upper part, with smaller muscles joining the two larger muscles 
and a small muscle extending to the vas deferens (fig. 7, RM, VIM). This 
form of musculature was more common than the one shown in fig. 12. The 
vergic sac and a part of the vas deferens are attached to the surface of the 
preputium, as shown in fig. 12. 

Internally (fig. 11), the large preputial cavity has two heavy, vertical 
pilasters (PL). In the upper part of the preputium, there is a peculiarly 
shaped penial gland (GL). It is shown somewhat restricted in fig. 11 and 
drawn upward in the preputial sac. There is a conspicuous gland appendage 
(GA). The verge (V) is very small (0.7 mm. long) and very narrow and is 
attached to the vas deferens at about the apex of the preputial sac. When 
fully extended, the penial gland has the form shown in fig. 1. The gland 
becomes a rosette surrounding the opening into the vergic sac (X in figure) , 
and the gland appendage (GA) extends forward (or downward) in the 
preputial cavity, ending in two lateral swellings which notably resemble 
the glans penis of the human genitalia. There is a narrow canal or channel 
which extends down the center of the appendage for its entire length (C). 
A cross section of the appendage indicating the ]X)sition of this canal is 
shown in fig. 2 (C). 

The verge (highly magnified) is shown in fig. 6. It is short and narrow, 
somewhat enlarged toward the lower end, with a centrally located sperm 
canal and exit. There is a narrow vergic sac cavity ( VO) . The channel 
which extends down the center of the penial gland appendage is seen to 
extend upward and into the vergic sac cavity (C). There is a small penial 
appendage beside the sperm canal outlet of the verge which is flattened 
and extends diagonally from the end of the verge, as shown in fig. 8 (PA). 

Female Organs. The spermatheca (S) is large and pyriform in general 
shape (fig. 13 », about 1.5 mm. long and 1 mm. wide. The duct (SO) is 
2.5 mm. long and is a narrow tube. The vagina (VG) is narrow, a trifle 
more than 1 mm. long and less than 0.5 mm. wide. The uterus (U) begins 
with the same diameter as the vagina but rapidly enlarges to about 1 mm. 
wide. It is about 8 mm. long. The nidamcntal gland (NG) is a large sac- 
like organ 3.5 mm. long and about 2 mm. in diameter (see fig. 4, NG). The 
oviduct (OD) is over 4 mm. long and is a large flattened tube about 
0.5 mm. in diameter. There is a large carrefour ((5Fj. The albumen gland 
(fig. 9) is squarish in shape and is composed of many small follicles. 

Hermaphrodite Organs (fig. 13). The ovotestis (OT) is very long and 
occupies a little more than one whorl. It is composed of many diverticula 
which form a pavement-like pattern on the surface of the ovotestis. In 
section (fig. 5), the organ shows seven main diverticula each of which is 



Subjamilies, Genera, and Subgenera — Recent and Fossil 169 

divided into four secondary branches. In fig. 3, a single ripe ovum is shown 
in the diverticulum. The free portion of the ovisperm duct (SO) is about 
5 nnn. long between the seminal vesicle and the oviduct and only 1 mm. 
long between the vesicle and the ovotestis. 

The published figures of the genitalia of Planorbarius corneus vary 
considerably. That of Simroth (1912, tafel 26, fig. 3) is one of the best 
and agrees with our fig. 13 on plate 20 in general gross anatomy. Lacaze- 
Duthier's figures are also accurate as regards general anatomy and nerve 
organization (1872, plate 20). L. Soos's figure (1917, p. 37 ( lacks detail. 
Germain's figure of the genitalia of Planorbis corneus (1931, p. 518) lacks 
details of structure and is less clear than that of Simroth. 

The published figures of the external and internal aspects of the penial 
complex have been inaccurate, either in figuring or in the interpretation 
of parts of the organs. Moquin-Tandon (1855) on his plate 32, fig. 3, shows 
the gland of corneus which is called the penis (verge), the lower part being 
designated as a dilation and the end of the groove is said to represent the 
stylet. Buchner (1891, tafel 5, fig. 1, copied by Simroth, 1912, p. 502) shows 
the penial complex incorrectly. Internally, the first type of the penis (penis 
complex) of corneus is an error of interpretation, the penis of Buchner not 
being the true verge but the gland appendage, which has a channel down 
the center, thought to be the sperm canal by Buchner. F. C. Baker ( 1928, 
I, p. 308) has copied these figures and has erroneously accei^ted the division 
into types of the male organ in Planorbis. Other authors, as Annandale 
(1922), have also used these penial subdivisions. Baudelot (1863, plate 4) 
correctly figures the cylindrical appendage and gland but the appendage is 
erroneously called the penis. Taylor (1900, p. 366) figures the terminal 
bulbous portion, calling it the vibratile stimulating appendage, which it 
probably is. 

The true nature of the gland and its appendage and the very small 
true verge have not been recognized and figured until F. C. Baker's paper 
appeared in 1931 (p. 579, plate 1). The small verge appears to be an en- 
largement of the vas deferens and has been completely overlooked. 

Respiratory and Renal Systems. The pseudobranch (plate 20, fig. 10) 
is an oval, elongated body extending from the anal region. It is usually 
somewhat leaf-like but, as in the figure, it may often be folded forming a 
rounded tube (P). The rectum (R) is large, rounded, and bears a simple, 
rounded crest or ridge, which does not extend over the pseudobranch as in 
Helisoma. The anal opening is above the pseudobranch (A). There is a 
large pneumostome (PS). 

The kidney is in general like that of Helisoma corpulentum (plate 44, 
fig. 3) except that it is longer and wider (14 mm. long and 4 mm. wide 
at the upper part). The portion of the kidney bordering the pericardium 
is flattened or even a trifie concave, the lower part is rounded and lobate 
on both margins, the lobations being more numerous than in Helisoma 
corpulentum. There is a large ridge extending down the center of the 
kidney. A cross section of the kidney near the lower end (plate 45, fig. 18) 
shows a rounded lumen (TK) with a vein on each side at the lower angle 
of the lumen (RA, AP). There is a high, sharp crest or ridge (RK) causing 
the section to be higher than wide. The ridge on the mantle, to the left in 
the section, is wide, high, and curved (RD). 



170 The Molluscan Family Planorhidae 

Digestive System. The digestive system is like that of the Heliso- 
matinae in general. The stomach region is rather narrow and resembles 
that of Promenetus exacuous figured on plate 48 (figs. 4, 5). There is a 
large blind sac or caecum. The intestine makes a coil about the stomach 
and another around the liver. The buccal sac is pyriform, elongated, with 
a short, rounded radula sac. The salivary glands are short and are com- 
posed of large branched follicles, in this respect diff'ering from the salivary 
glands of Helisoma. 

The superior jaw (plate 50, fig. 14) is wide and low. convex, the ends 
attenuated and bent downward. The face of the jaw is heavily vertically 
striated. The side jaws are very narrow and as long as the width of the 
superior jaw. 

Radula (plate 66, fig. 2). Center tooth higher than wide, the two spade- 
shaped cusps not reaching the lower margin of the base of attachment. 
Lateral teeth (1-9) squarish, tricuspid, the cusps sharply pointed, the 
mesocone larger than either the entocone or ectocone. Intermediate teeth 
(10-14) narrower than the lateral teeth, the entocone breaking up into two 
to four sharp, pointed cusps, the ectocone becoming bicuspid. Marginal 
teeth (15-38) narrow, the entocone breaking up into five to six subequal 
cusps, all in a straight row, the ectocone becoming tricusind, the cusps very 
small. The mesocone remains large in all teeth with but little modification. 
The outer marginals (39-42) are very narrow, much smaller than the other 
marginals, the cusps becoming very small and forming a serrated outer 
margin of the teeth. 

Germain (1931, p. 518) figures the radula of corneus as having inter- 
stitial cusps, but such were not observed in the material personally ex- 
amined. Taylor (1900, p. 270) figures the laterals as bicuspid and in this 
he is followed by Simroth (1912, p. 316). All specimens studied have had 
tricuspid lateral teeth, as has been noted for every genus in the family as 
yet examined. Taylor also figures thirty-three teeth in a row while in 
specimens personally examined the number has been from forty-two to 
forty-five. In some specimens from Germany, there were odd teeth (72nd 
row, 12-15, marginal) in which the cusps of the endocone were uneven 
and the smaller ones might be assumed to be interstitial cusps. Some outer 
marginals (17, 20, 22) were of a like nature. 

The following radulae have been examined: 

Locality Formula Rows Source 

Poland, near Warsaw 42-1-42 200-217 Mr. A. Jankowski 

Germany 45-1-45 170-210 Dr. F. Haas 

Florida (aquarium specimen) 45-1-45 200-218 Mr. Roger P. Gray- 

Material from the following sources has been used for the above data: 
Branch of Wista River at IVIorysinek, 5 km. south of Warsaw, Poland, col- 
lected by Mr. A. Jankowski; Germany (locality unknown) from Dr. F. 
Haas; Ojus, Florida; Copenhagen red snails, bred for aquaria, Air. Roger 
P. Gray, sent by Air. T. Van Hyning. 

Geographical Distribution, Great Britain and Europe east to northern 
and western Asia, south to Portugal and Italy. It has been introduced into 
New Jersey, Puerto Rico, and probably other places. Whether the larger 
species found in northern Africa are referable to Planorbarius can only be 
determined bv an antomical examination. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 171 

Just how many species may be included in Planorbarius is somewhat 
of a question. Germain (1921, 1931) includes one species with several 
varieties. In the catalogue of Planorbidae in the Indian Museum, Germain 
includes in Planorbis (= Planorbarius) several species which belong in 
other genera, principally Afroplanorbis. 

Species Considered as Valid. Since the members of this genus are 
extralimital, the species listed by Westerlund which appear to be referable 
to Planorbarius are cited here. 

Planorbarius corneus (Linn.) Planorbarius metidjensis (Forbes) 

Planorbarius elophilus (Bgt.) Planorbarius stenostoma (Bgt.) 

Planorbarius kabylianus (Let.) 

Geological Distribution. According to Wenz (1923, p. 1481), the genus 
Corneus ( = Planorbarius) begins in the late Eocene period. 

Remarks. The genus Planorbarius is at once distinguished from all 
other groui)s of Planorbidae by characteristics of the. genitalia. The very 
large preputium and very small vergic sac are particularly noteworthy, 
and the form of the penial gland with its elongated appendage and the 
very small verge are unique features of the genus. The two retractors of 
the penial complex are also diagnostic features. The structure of the pros- 
tate and ovotestis is likewise distinctive. No specimens with everted gland 
or verge have been observed and one can only surmise that the gland is 
everted as an excitatory organ and probably the small vergic sac and verge 
are extended from the male opening, as has been observed in Helisoma. 

Almost all writers on European fresh-water Mollusca have mistaken the 
penial gland appendage for the true penis (verge) and have completely 
missed the small, vestigial true penis. Other authors have ignored all details 
of the internal anatomy of the penial complex, simply figuring the large 
pre]:)utium and the vas deferens as directly entering this organ. 

The systematic position of Planorbarius is without doubt in the sub- 
family Helisomatinae. The presence of the penial gland and the multiple 
character of the diverticula of both prostate and ovotestis indicate this 
relationship. The strongly ridged kidney is also another evidence of this 
kinship. It is the only group of the subfamilv thus far known outside of 
America. The large shell resembles that of Helisoma especially the sub- 
genus Pierosonia. 

The proper genus for the reception of the Helix cornea of Linn, has 
been in some dispute. Many authors have considered it the type of the 
genus Planorbis of Miiller. Dall (1905) considered it the type of Planorbis, 
dating it from Montfort, 1810, who definitely established cornea as the 
tvpe of the genus. This procedure has been followed bv Germain (1921), 
Pilsbry and Beciuaert (1927), Lindholm (1926), Baker "( 1931) , and Thiele 
(1931). Dall's conclusions were questioned by Kennard and Woodward 
(1924) who maintained that the type of the genus Planorbis is the Helix 
planorbis of Linn, by absolute tautonomy. H. B. Baker (1930) has also 
expressed the same opinion. Germain, in a later work (1931), cites the 
Helix planorbis of Linn, as the tvpe of Planorbis Guettard 1756 and 
Geoff roy 1767. 

The generic name Coretus is in current use by many European con- 
chologists. Some of these use the Coretus of Adanson 1757 (as Clessin 
1886 and Germain 1931) but that author was non-binomial and pre- 



172 The MoUuscau Family Plauorbidae 

Linnean, furthermore, he applied the name to a minute species about an 
eighth of an inch in diameter. In 1847, Gray (P.Z.S., p. 508) used the name 
Coretus, as of Adanson, but definitely cited the Helix cornea of Linnaeus 
as the type. Later authors (Wenz, 1923, Haas, 1929) use Coretus Gray, 
1847, with the type Helix cornea. 

In 1806, Dumeril (Zool. Analyt., p. 164) coined the name Planorbarius 
for a group of mollusks, without an operculum, inhabiting fresh water. 
Except for the name, which suggests Planorbis, the group might pass for 
anything among fresh-water pulmonates and the name is absolutely use- 
less for purposes of nomenclature. In a German edition of Dumeril's work, 
however, Froriep used this name and supplied a type, the Helix cornea 
of Linnaeus which, according to Opinion 46 of the International Code, 
becomes the monogenotype of the genus Planorbarius of Froriep. This 
antedates INIontfort's use of corneus as a genotype by four years. 

Froriep says of Planorbarius in his German translation (p. 165) : 

Die Scheibenschnecken {Planorbarius) iinterscheiden sich (die Schaele ubemick- 
sichtiget) \on den vorigen niir durch den mangelnden Schliessdeckel. Es sind dies 
Flussschnecken. Z.B., Helix cornea. 

The case is much better than that of Coretus Gray and there appears to be 
no reason why Planorbarius, as published by Froriep, should not be used 
for the large European snail jireviously known as Planorbis corneus. The 
rarity of Froriep's translation in libraries has doubtless been the cause of 
its being omitted in most })rcvious discussions of planorbid nomenclature. 

Subfamily PLANORBULINAE Pilsbry, 1934 

Prostate diverticula compound but not fan-like in section, there being a 
main division from which branch, on one side, several (four to six) smaller 
diverticula. The ovotestis diverticula are placed in pairs. There is a pcnial 
gland but no external duct, which is always placed inside of the preputium. 
The jaws are as in Helisomatinae. 

Type genus Planorbula Haldeman. 

The few groups belonging in this subfamily are noted below: 

With short, tube-like duct: Planorbula, Proynenelus. 

Without distinct duct but with open channel: Menetus, Micromcnctus. 

The fossil group Planobifex Pilsbry doubtless belongs in this subfamily. 

Genus PLANORBULA Haldeman. 1840 
Type by original designation Plajwrbis armigerus Say 

1840. Di.-<c}(s Haldeman, Mon. Limn. Part I, p. 4 of cover, July, 1840. Non Fitzinger, 
1833, a land genus. Type Planorbis armigerus Say. As subgenus 

1840. Planorbula Haldeman, op. cit., Suppl. to Part I, p. 2 (Oct. 1840). New name for 
Discus Haldeman, preoccupied 

1842. Planorbula H.'VLDEman, Mon. Limn., Part IV, Physidae, p. 14. Monotype Pla- 
norbis arynigerus Say. As subgenus 

1847. Dentatus Gray, Proc. Zool. Soc. London, p. 181, non Beck, 1837. Type Planor- 
bis armatus Gray, supposed to be the same as Playwrbis armigerus Say. As 
subgenus of Coretus 

1855. Plariorbula H. and A. Adams, Genera of Rec. Moll., II, p. 265. Type Planorbis 
armigerus Say. As subgenus 

1865. Planorbula Binney, L. and FW. Sh. N. A., II, p. 136. No type cited, but 
Planorbis armigerus Say by assumption. As subgenus of Segmentina 



Subfamilies, Genera, and Subgenera — Recent and Fossil 173 

1870. Phniorbiila Dall, Ann. N. Y. Lye. N. H., IX, p. 352. Type Planorhis armigerus 

Say. As subgenus of Segmentimi 
1870. Segmentina Tryon, Con. Hald. Mon., p. 213 (non Fleming). No type cited but 

Planorhis armigerus Say, listed. 

1883. Planorbula Fischer, Man. de Conch., p. 509. Type Planorhis armigerus Say. 

As subgenus of Planorbis 

1884. Planorbula Tryon, S. & S. Conch., Ill, p. 107. Type Segmentina armigera (Say). 

Subgenus of Segmentina 

1886. Planorbula Clessin, Conch. Cab., XVII, p. 35. Type Planorbula armigera (Say). 
As genus 

1899. Planorbulina M.\rtexs, Biol. Cent. Amer., Moll., p. 400. Clerical error for Pla- 
norbula. May equal Tropicorbis in part. For group of Planorhis armigerus Say 

1902. Planorbula F. C. Baker, Moll. Chicago Area, Part II, p. 300. Radula figured. 
As subgenus of Segmentina 

1905. Planorbula Dall, Alaska Moll., p. 97. Type Planorbis armigerus Say. As sub- 

genus of Segmentina 

1906. Planorbula Pilsbry and Ferriss, Proc. Acad. X'at. Sci,. Phil., p. 166. As sub- 

genus of Segmentina 

1909. Planorbula Pallary, Mem. Inst. Egypt, VI, p. 59. As genus. Doubts that Pla- 
norbula of America is found in Egypt 

1912. Segmentina (part) Hannib.^l, Proc. Mai. Soc. London, X, p. 154. A group 
mixture, but includes Planorbula of Haldeman. 

1918. Planorbula Walker, Miscel. Papers Mus. Zool., Univ. Mich., X^o. 6, pp. 14, 104. 
Type Planorbis armigerus Say. Shell and radula. As subgenus of Segmentina 

1923. Planorbula Germain, Rec. Ind. Mus., XXI, p. 179. Type Planorbis armigerus 
Say. As genus 

1926. Planorbula F. C. Baker, Trans. Wis. Acad. Sci., Arts, and Lett., XXII, p. 203. 
Type Planorbis armigerus Say. As genus 

1926. Planorbula Lindholm, Archiv. fiir Mollusk., 58 year, Heft 6, p. 258. Thinks it 

should be separate genus 

1927. Planorbula Pilsbry and Bequaert. Bull. Amer. Mus. N. H., LIII, p. 131. Mono- 

type Planorbis armigerus Say. As genus 

1928. Planorbula F. C. Baker, Fresh-water Moll. Wis., I, p. 353. Type Planorbis 

armigerus Say. Genitalia, jaw and radula figured. As genus 

1930. Planorbula H. B. Baker, Occ. Papers Mus. Zool., Univ. Mich., No. 210, p. 43. 

Monotype Planorbis armigerus Say. As genus 

1931. Planorbula Thiele, Handbuch, 2 Teil, p. 480. Type Planorbis armigerus Say. 

As genus 
1934. Planorbula Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 54. Form of pro.state and 

presence of penial gland indicated 
1934. Planorbulina Pilsbry, loc. cit., p. 54. Typographical error of von Martens for 

Planorbula. Type designated by Pilsbry Planorhis armigerus Say 
1940. Planorbula H..\ldeman, Morrison, Nautilus, LIV, p. 65. Notes correct date of 

publication, Oct. 1840 

Subgenus PLANORBULA SS. 

Type by original designation Planorbis arjnigerus Say 

Shell (plate 79, figs. 25-27). Small, ultradextral, of few closely coiled 
whorls, slowly increasing in diameter, with flatly rounded whorls above 
and a wide depression below, the body whorl usually carinate in the 
middle; lips more or less thickened by a varix. Aperture with six lamellae 
situated well within, placed as follows: a large parietal lamella, somewhat 
sigmoid, obliquely transverse, with a small tubercular lamella below, at 
the left end of the parietal lamella; four palatal lamellae (plate 76, fig. 8), 
a large slightly transverse basal (4), a large lower palatal (3) which is 



174 The Molluscan Family Planorbidae 

always directed upward, an upper palatal above and smaller than the lower 
palatal (2), also pointed upward, and a suprapalatal (1) which is usually 
in a transverse position. This lamella may be vestigial or absent in some 
forms of Planorbula. Only one set of lamellae occurs in each shell although 
the lamellae are found at a very early period in the age of the individual, 
the old set appearing to be absorbed before the new one is formed as the 
shell increases through growth. 

Animal (plate 70, fig. 11). The living animal of Planorbula jenksii from 
Lake Wentworth, New Hampshire, is almost black, the foot with lighter 
edges. The tentacles are long and tapering, blackish in color with a light 
zone near the head; a blackish band borders the head and neck above the 
foot and velar area; the top of the head is wine-colored or reddish, the sides 
of the body lighter; the black eyes are placed at the inner bases of the 
tentacles. The mantle is blotched with dark gray dots. The stomach 
region is pigmented. The liver and ovotestis are yellowish. The velar area 
is very wide and extends beyond the foot when the animal is in motion. 
The shell is carried tilted to the left, at an angle of about forty-five 
degrees. It is sometimes carried flat, the left side lowermost. 

ANATOMICAL CHARACTERISTICS 
PLATE 37 (Planorbula nnnigcra (Say) ) 

GENITALIA. Male Organs (fig. 4). The seminal vesicle (SV) is about 
1 nnn. long and 0.5 mm. wide and is composed of a cluster of small glands 
or follicles. The sperm duct (SPD) is roundly enlarged at its distal end 
(about 0.5 mm. long and wide) tapering anteriorly to less than half this 
diameter under the prostate. The prostate (PRS) is about 1.5 nnn. in 
length and less than 0.5 mm. in height. In section (figs. 1, 2), the prostate 
is seen to be composed of a long diverticulum to which are attached, on one 
side only, five or six smaller and shorter diverticula, several of which may 
be branched two to four times. There are about thirty rows of diverticula in 
the i:)rostate. The vas deferens is of smaller diameter than the sperm duct, 
for the most part about half this diameter, and is 6 nnn. long. 

The penial complex (fig. 9) has a strikingly jiyriform preputium, nar- 
rowing anteriorly to a round tube of small diameter. The preputium is 
less than 1 mm. long and a trifle more than 0.5 mm. in diameter at its 
greatest width. The vergic sac is cylindrical in form, about 0.3 mm. in 
diameter and as long as the preputium. There is only a slight constriction 
between the preputium and the vergic sac. There is one heavy retractor 
muscle (RM) attached to the summit of the preputium near the vergic 
sac. Three wide supporting muscles are attached to the upper and middle 
area of the preputium. There is no external penial gland duct. The penial 
complex of another six^cimen shows a more swollen preputium and a wider 
vergic sac (fig. 10). 

Internally (fig. 11), the preputium has two heavy vertical pilasters 
(PL) the left one sending a transverse, thick, rounded fold or ridge across 
the upper part of the preputial sac to the right pilaster. There is a rounded, 
basin-shaped penial gland (GL), with a shallow cup, the walls of which 
have many vertical folds (fig. 6, GF). There is no external gland duct, 
but a shallow channel, open above (DC), connects the penial gland with 
a circular space bordering externally the high, thick, fleshy muscular ring 
or diaphragm between the ring and the body wall of the prei)utium 



Subfamilies, Genera, and Subgenera — Recent and Fossil 175 

(fig. 11, D). The verge (V) is sac-like, about 1 mm. long, and tapers to a 
point at its lower end (fig. 12). The sperm canal extends through the center 
of the verge and has a central outlet bordered by a small penial papilla 
(fig. 8). 

Female Organs (fig. 4). The spermatheca (S) and spermathecal duct 
(SD) are about 1.3 mm. long, the duct and gland of equal length and the 
gland swollen to more than twice the diameter of the duct. The vagina 
(VG) is 0.8 mm. long and 0.3 mm. wide the spermathecal duct entering it 
rather high. The uterus (U) is about 2 mm. long and is but little wider 
than the vagina. The nidamental gland is slightly wider than the uterus 
and is located beneath the prostate. The oviduct (OD) is over 2 mm. long 
and is of the same diameter as the sperm duct. It is somewhat convoluted 
at the upper end, where there is a large carrefour (CF) which receives the 
long duct from the albumen gland (fig. 3, DA, AL). The albumen gland 
(AL) is large, about 1 mm. in diameter, somewhat triangular in shape, and 
is folded for the passage of the intestine. 

Hermaphrodite Organs. The ovotestis (fig. 4, OT) occupies a little 
more tlian one whorl and is composed of long, club-shaped diverticula ar- 
ranged in pairs (fig. 7) , each pair bending to right or left or placed in the 
center. There is a very short free ovisperm duct between the ovisperm duct 
and the seminal vesicle, and a longer, narrow duct (2 mm. long) between 
the seminal vesicle and the oviduct. A few vesicles extend down a part 
of the ovisperm duct from the seminal vesicle. 

The genitalia of Planorbula jenksii are in most respects like those of 
armigera. The prostate has about twenty-five rows of diverticula while 
in armigera there are thirty rows. 

No figures of the genitalia of Planorbula have been published previ- 
ously, except those by F. C. Baker (1928, p. 356, figs. 153, 154). The 
figure of the entire genitalia (1928, fig. 153) is incorrect in several par- 
ticulars, especially in the form of the prostate and the seminal vesicle. The 
diagrammatic figure of a secion of the penial complex (1928, fig. 154) is 
more nearly correct, but does not show the details of the penial gland. 

Respiratory and Renal Systems. The pseudobranch (plate 37, fig. 
5, P) is rounded and has a ridge extending down the middle which con- 
nects with a crest-like ridge on the rectum (R). The ridge on the pseudo- 
branch is heavy and when bent over (as shown in the figure) causes the 
pseudobranch to appear folded. There is a large pneumostome (PS). The 
pseudobranch of jenksii is like that of armigera. 

The kidney (plate 45, fig. 3) is long and narrow (5.5 mm. long, 1 mm. 
wide at the pericardium). The ureter is sharj^ly recurved and is directed 
upward into the mantle cavity. The pericardium is about 1 mm. long. In 
section (fig. 13, near middle), the kidney is seen to be much flattened, with 
the lumen twice as wide as high and with a vein at each end. There is no 
ridge on the kidney. 

Digestive System. The digestive organs (narrow stomach, crop, and 
pyloris) are similar to those in Carinifex and Parapholy.r. The intestine 
makes a loop around the stomach, passes backward to the liver, makes 
another loop and runs forward to the rectum, ending in the anus over the 
pseudobranch. There is a conspicuous blind sac or caecum. Both jenksii 
and armigera have the same type of digestive system. The buccal sac is of 



176 The MoUuscan Family Planorhidae 

the same form as that of Carinifex. The salivary glands extend half their 
length behind the buccal sac and form a loop. 

The superior jaw of armigera (plate 50, fig. 2) is slightly arched, about 
four times as wide as high and finely, vertically striated on the anterior 
face. The side jaws are about as long as the width of the superior jaw and 
are shaped as in Parapholyx. The jaws of jenksii (fig. 3) are the same as 
those of armigera. 

Radula of armigera (plate 65, fig. 1). The center tooth is slightly 
higher than wide with a bicuspid reflection which does not reach the lower 
margin of the base of attachment. The lateral teeth (1-8) are squarish 
with three long, spade-like cusps of the same shape. The intermediate 
teeth (9-11) have the ectocone split two or three times, the cusps sharp. 
The marginal teeth (12-19) are long and narrow with cusps at the lower 
end. The endocone at first is split into two cusps about as long as the meso- 
cone (12-13) ; they then become split into four small, equal cusps (14-16). 
The ectoconic margin has three to four small cusps. The outer marginal 
teeth are shorter than the earlier marginals but have the same form (19). 
The radula of jenksii has the same form of teeth. 

Radula Data for Pkmorbula 



Species 


Forumla 


Locality 


Rows 


Source 


armigera 


18-1-18 


Murphy Creek, Wisconsin 


160-165 


Dr. C. Judav 


armigera 


24-1-24 


Snodgrass Lake, Ontario 


160-165 


Dr. A. R. Cahn 


armigera 


18-1-18 


Devil's Lake, Wisconsin 


125-140 


F. C. Baker 


armigera 


19-1-19 


Douglas Lake, Michigan 


125-140 


Dr. F. Smith 


jenksii 


19-1-19 


Unionville, Connecticut 


145-150 


F. C. Baker 



The data for the material examined anatomically are as follows : 
armigera, Murphy Creek, near Madison, Wisconsin; Snodgrass Lake, On- 
tario; Devil's Lake, Wisconsin; Douglas Lake, ]\Iich.; jenksii, Roaring 
Brook, Unionville, Connecticut. Five specimens from each lot of armigera 
were examined and about fifteen specimens of jenksii. 

Geographical Distribution. Planorbula is wholly an American genus 
distributed from Great Slave Lake and Fort Smith, ^Mackenzie River, 
south to Georgia and Louisiana, and from the New England states west to 
Nebraska. 

Species Considered as Valid. The following are recognizable as be- 
longing to this genus: 

Planorbula armigera armigera (Say) Planorbula jenksii (H. F. Carpenter) 

Planorbula armigera palustris Baker Planorbula campestris (Dawson) 

Planorbula crassilnbris (Walker) {^ christyi Dall) 

Geological Distribution. Pleistocene to Recent fauna. 

Remarks. Planorbula is a distinct and characteristic genus of American 
Planorbidae. The name has been used to cover many dentate planorbids, 
such as Tropicorbis of the tropics and certain forms of north Africa be- 
longing to Ajroplanorbis. It is in no way related to these groups, which 
belong in the subfamily Planorbinae. Planorbula of Haldeman belongs in 
a separate subfamily related to Helisomatinae, having a distinct penial 
gland and multiform prostate and ovotestis diverticula. 

The lamellae within the aperture are also different in the two groups — 
in Tropicorbis the large lower palatal lamella is always pointed downward 



Suhjamilies, Genera, and Subgenera — Recent and Fossil 177 

while in Planorbida this lamelhi points iiiiward. In Planorbula, the pHcae 
are always present but in Tropicorbis they may be absorbed late in life and 
the aperture become edentulous (see remarks under Tropicorbis) . 

Planorbula has also been subordinated to Segmentina as a subgenus 
but it has no relationship to that genus, the internal organs being of a 
totally different character. Segmentina is the type genus of the subfamily 
Segmentininae. 

The chief characteristics of the genus Planorbula are the ovate or 
rounded penial gland without an external duct but with a canal-like duct 
within the preputium, and the prostate with small, branched diverticula 
on one side of a main diverticulum. Its nearest relative is Proinenetus, with 
which it agrees in general in the form of prostate and penial gland. These 
genera and their relatives constitute a subfamily Planorbulinae, as sug- 
gested by Pilsbry in 1934 (p. 47). 

Subgenus HALDEMANINA Ball, 1905 

Type by original designation Planorbis wheatleyi Lea 

1905. Holdemaniua Dall, Alaska Moll., p. 97. Type Pkmorbis wheatleyi Lea. As 

section of subgenus Planorbula Haldeman 
1918. Haldemanina W.^lker, Miscel. Pub. Mus. Zool., Univ. Mich., Xo. 6, p. 105. Type 

Planorbis wheatleyi Lea. Synonym of Planorbula 
1923. Haldemanina Germ.^in, Rec. Ind. Mus., XXI, p. 181. T3'pe Pla7iorbis wheatleyi 

Lea. Considered synonym of Planorbula 
1931. Haldemanina Thiele, Handbuch, Teil 2, p. 480. T3-pe Planorbis icheatlcyi Lea. 

As synonym of Planorbula 

Shell (plate 79, figs. 28-30). As in Planorbula but with the aperture 
notably thickened, the lower palatal lamella within the aperture very long 
and curved upward as far as the upper palatal lamella. 

Animal. The animal is unknown anatomically. 

Geographical Distribution. Xot at present known outside of the state 
of Alabama. 

Species Considered as Valid. Planorbula (Haldemanina) wheatleyi 
(Lea). tyi)e of this subgenus, is the only species ascribed to it. 

Remarks. In 1905 (p. 97), Dall instituted a section Haldemanina to 
contain the Planorbis wheatleyi of Lea. No particular characteristics 
different from Planorbis armigera appear in his diagnosis, except the state- 
ment 'lamellae complex.' Upon examining the lamellae of wheatleyi, the 
complexity is at once seen. The lower palatal lamella is about twice as long 
as in armigera and the upper part is bent upward almost at right angles 
to the transverse lower part, so that this end is on a line with the upper 
palatal lamella, the whole lamella being bent like an Australian boomer- 
ang (see plate 76, fig. 9, wheatleyi; fig. 8, armigera). 

Authors, generally, have considered Haldemanina an absolute syn- 
onym of Planorbula, but the difference in the lower palatal lamella is 
persistent in all specimens of wheatleyi here examined and is not found in 
any other species or race of Planorbula. The writer, therefore, is disposed to 
accept Haldemanina as a subgroup under Planorbida. The thickening of 
the lip has no special significance, as this is found in several species of 
Planorbula. 



178 The Molluscan Family Planorbidae 

Genus PROMENETUS F. C. Baker, 1935 

Type by original designation Planorbis exacuous Say 

1928. Menetus F. C. Baker, Fresh-water Moll. Wis., I, pp. 357, 360, 362 (non H. and 

A. Adams). Genitalia of Planorbis exacuous Say 
1935. Promenetus F. C. B.\ker, Nautilus, XLIX, p. 48. Type Planorbis exacuous Say. 

As new group 

Shell (plate 79, figs. 19-21). Ultradextral Avith a small number of whorls 
rapidly increasing in diameter, carinated or rounded; left side with broad 
spire depression exhibiting all of the whorls; right side flat, also exhibit- 
ing all of the whorls; aperture wider than high; outer lip thin. 

Animal. External features similar to those of Planorbula. Foot very 
short and rounded. Color blackish. 

ANATOMICAL CHARACTERISTICS 
PLATE 41 {Promenetus exacuous (Say) ) 

GENITALIA. Male Organs (fig. 10). The seminal vesicle (SV) is about 
2 mm. long, is nearly three times the diameter of the ovisperm duct and has 
many small diverticula or vesicles, about as long as the diameter of the 
seminal vesicle, projecting from one side of the organ. The sperm duct 
(SPD) is about 1.5 mm. long and 0.3 mm. in diameter and appears 
sausage-shaped. The prostate (PRS) is 1.5 mm. long and is composed of 
thirteen multiple diverticula. In section (fig. 5) the prostate is seen to have 
four supplementary diverticula projecting from the side which lies next 
to the oviduct. An unusual form of prostate is shown in fig. 11, plate 42 
(P. exacuous megas) in which the three supplementary diverticula are each 
branched three times at the extremity. The vas deferens (VD) is about 7 
mm. long and about one third the diameter of the sperm duct, which, itself, 
also diminishes greatly in diameter beneath the prostate. 

The i)enial complex (plate 41, fig. 2) is 3 mm. long, the pyriform 
preputium occupying half of the length, the much narrower vergic sac the 
other half. There is no sharp constriction between the upper and lower 
sacs, the preputium simply narrowing as it joins the vergic sac. There is 
one narrow retractor muscle (R]M) and a wide group of three to five 
sujiporting muscles (SAI) forming a lattice-like pattern. The vas deferens 
enlarges only slightly as it enters the vergic sac (VD). In fig. 1, a penial 
complex is shown in which the preputium is much swollen by the enlarged 
penial gland. The penial complex of variety mcgas docs not differ from 
that of exacuous. 

Internally (fig. 3), the preputium has two heavy pilasters (PL) to the 
upper part of the left one of which the penial gland is attached (GL). The 
gland appears sac-like as seen from the side and is bent crosswise in the 
cavity of the preputium. There is a wide projection at the end of the gland 
in which there is an open groove (DC) or channel connecting the gland 
with the muscular ring or diaphragm (D) and separating the upper from 
the lower cavity. In fig. 3 on plate 42, the penial gland is shown from 
above, the pilasters separated to show the ovate cup of the gland and the 
glandular folds lining the walls of the cup. A longitudinal section of the 
gland (plate 42, fig. 7) shows the arrangement of the vertical folds within 
the gland. 

The verge (V) is long and narrow, usually filling the vergic sac (plate 
41, fig. 3) and protruding from the diaphragm into the preputial cavity. 



Subfcunilies, Genera, and Subgenera — Recent and Fossil 179 

In fig. 12, plate 42. the verge is shown in this condition, with the penial 
gland (GLj extended crosswise of the preputial cavity. The end of the 
verge of variety megas is shown in fig. 13, plate 42, indicating the centrally 
located opening of the sperm canal with a small jienial papilla placed just 
below and to one side of the opening. A circular ridge near the end of the 
verge was observed in this specimen which did not appear in others 
examined. 

In a specimen of variety tnegas (fig. 4. plate 42), the gland was some- 
what contracted but showed well the trough-like canal or channel con- 
necting the gland with the circular canal near the diaphragm. In this speci- 
men, the side ridges or bands of muscle connecting the two pilasters with 
this canal are well shown. A specimen from Winnebago Lake had the 
verge and penial, gland extended from the male opening and lying on the 
neck of the animal (plate 41, fig. 91. 

Female Organs (plate 41, fig. 10). The spermatheca (S) is irregularly 
ovate, bulging in the center, with a wide duct (SD) about as long as the 
spermatheca, the two parts together measuring about 2 mm. The vagina 
(VG) is wide and a trifle more than 1 mm. in length. The uterus (U) is 
the same width as the vagina and narrows only at the upper part of the 
oviduct (OD). The uterus and oviduct combined are about 4 mm. long. 
The nidamental gland (XG) is about 1.5 mm. long. The relationship of 
the sperm duct, oviduct, ovisperm duct, carrefour, and albumen gland duct 
is shown in fig. 10, plate 42 (of variety megas). The duct of the albumen 
gland is quite long and folded in an S form. The albumen gland (plate 41, 
fig. 7) is about 2 mm. long and half as wide. 

Hermaphrodite Organs. The ovotestis OT, (plate 41, fig. 10) occupies 
a little more than one whorl (fig. 6). In section (fig. 4), it is seen to be 
composed of twin, club-shaped diverticula, both glands entering the ovi- 
sperm duct. Sections of variety megas are shown on plate 42, one near the 
middle of the ovotestis (fig. 8) and one near the posterior end (fig. 9). The 
ovisperm duct (free portion) extends about 1 mm. on each side of the 
seminal vesicle and is without glandular projections or swellings. 

A related species, Promenetus innhilicatellus, formerly known as 
Gyraidiis umbilicatiis, shows some differences and the anatomy of this 
species is shown on plate 43. The seminal vesicle is about twice the di- 
ameter of the ovisperm duct (fig. 1) and is bordered on both sides by 
several more or less sharply pointed gland-like protuberances. Small 
vesicles project from the ovisperm duct for a long distance (over 1 mm.) 
below the seminal vesicle. The sperm duct (SPD) is short, and narrow 
(less than 1 mm. long) and is a small tube. The jirostate (PRS) is about 
1 mm. long and is composed of twenty diverticula which appear very long 
and narrow when the prostate is in its natural position lying against the 
uterus. A section about midway of its length (fig. 6) shows five supple- 
mentary diverticula or six including the termination of the main diver- 
ticulum. The vas deferens (YD) is a narrow tube about 3 mm. long. 

The penial complex (fig. 4) is about 1.5 mm. long and the preputium 
and the vergic sac are of about equal length. The vergic sac is not much 
narrower than the preputium. the latter having a swelling or ridge at the 
upper part indicating the position of the diaphragm. There is one narrow 
retractor muscle (R^I) attached to the upper part of the preputium and 
a wide band of supporting muscle (S]\I) attached to the middle portion of 






liiflLIBRAR 



'*>A* 






180 The Molluscan Family Planorbidae 

the preputium. A small supporting muscle may be present on the preputium 
below the retractor muscle. 

Internally, the penial complex is like that of exacuous (fig. 3). There 
is a large penial gland (GL) which may be folded back as shown in fig. 
10. In section (fig. 11), it is like that of exacuous. There is an open, canal- 
like duct (see fig. 9). The verge (V) is short and wide, with a central 
opening of the sperm canal bordered by a distinct penial papilla (fig. 12). 

In the female system (fig. 1), there is a short spermatheca (S) with a 
wide duct twice as long as the spermatheca (SD). The vagina (V) is wide 
but shorter than in exacuous. The uterus (U) is wide and short and there 
is a swollen nidamental gland (NG). The oviduct (OD) is longer than in 
exacuous. The relationship of the oviduct, sperm duct and ovisperm duct 
is shown in fig. 7. The albumen gland is somewhat quadrangular in form 
and is composed of large vesicles (fig. 5). 

Of the hermaphrodite organs, the ovotestis is composed of paired 
diverticula. In the specimens examined, many of the diverticula were 
gravid (plate 43, fig. 1, (3T; fig. 8). The ovisperm duct differs from that of 
exacuous by having a number of small swellings on one side of the duct for 
half the length of the portion between the seminal vesicle and the oviduct. 
A portion of the ovisperm duct between the seminal vesicle and the 
ovotestis is without gland-like swellings. 

The penial complex of Menetus e.vacuou-s is figured by Baker ( 1928, p. 
357, fig. 154). The retractor muscle is shown with an attachment to both 
the preputium and the vergic sac. This feature was not observed in any 
specimens more recently examined and this figure must be considered 
abnormal. All material studied, of exacuous and umbilicatellus, had a 
single retractor without two branches for the vergic sac and the preputium. 
The same criticism extends to fig. 157 on p. 362 of the work mentioned. 

Respiratory and Renal Systems. The pseudobranch appears somewhat 
variable in form, the variation being largely due to the amount of expan- 
sion of the organ. In specimens of e.vacuous from Winnebago Lake, Wis- 
consin (plate 41, fig. 8), it is large and leaf-like. In an example from 
Wainwright Park, Alberta (plate 42, fig. 1), it is fully expanded, wide and 
rounded below, with the anal opening conspicuously placed on one side 
within the area of the i:)seudobranch. It is somewhat folded in the middle. 
In a specimen of variety megas from Paul Lake, British Columbia (plate 
42, fig. 2), the pseudobranch is rounded, and there is a smooth ridge extend- 
ing over a part of the rectum and forming a thickened border to the pseudo- 
branch. In umbilicatellus (plate 42, fig. 6), the pseudobranch is rounded in 
one specimen and folded in another (plate 43, fig. 2). In these examples, 
the anal region is outside of the area of the pseudobranch. There is no 
decided ridge on any specimen examined and the ridge on the rectum is 
not like that in Helisomatinae. 

The kidney (plate 46, fig. 3) of exacuous is 3.5 mm. long and about 
0.5 mm. wide, rather long and narrow. The ureter is a long tube and turns 
at right angles to the long diameter of the kidney. It borders the thickened 
mantle margin on the inside. The pericardium is less than 1 mm. long. A 
cross section of the kidney near the middle (plate 46, fig. 4) shows an 
ovate lumen with a small vein on each side. There is no superposed ridge. 
The kidney of umbilicatellus is of the same shape and general nature as 



Subfamilies, Genera, and Subgenera — Recent and Fossil 181 

that of exacuous, but the ureter bends backward at a sharper angle and is 
directed upward into the mantle cavity. 

Digestive System. The stomach is elongated with the gizzard longer 
than wide and with a rounded pyloris (plate 48, figs. 4, 5). There is a long 
blind sac or caecum (BS). The intestine (IN) makes a tight loop around 
the stomach, extends backward to the liver and then makes another loop 
and runs forward to the rectum. The buccal sac is elongated, with a 
rounded radular sac. The salivary glands are narrow, looped, and as long 
as the buccal sac. 

The superior jaw is arched, wide, and low, with the face vertically 
striated, as in other members of the group (plate 50, fig. 8, exacuous). In 
umbilicatellus (plate 50, fig. 15), there is a sharp median projection on 
the lower edge of the superior jaw. In exacuous, there is only a rounded 
bulge at this point. The side jaws are as in other species of the subfamily. 

The radula of exacuous has a squarish center tooth with expanded lower 
margins, the two wide, spade-shaped cusps not reaching the lower border 
of the base of attachment. The lateral teeth (1-6) are squarish, tricuspid, 
the mesocone longer and larger than the entocone and ectocone. All cusps 
are sharply pointed. The sixth lateral has a small cusp above the ectocone. 
Intermediate teeth begin on the seventh tooth, the entocone splitting into 
two long, sharp cusps and one or two small cusps appearing on the outer 
margin of the tooth above the ectocone (9-10). ^Marginal teeth (11-15) 
long and narrow, the entocone splitting into three to four small cusps and 
the outer margin of the teeth having two to three small cusps above the 
ectocone. The outer marginals are almost vestigial. The radula of umbili- 
catellus (fig. 2) is similar in form to that of exacuous. 

The radula data for Promenetus are as follows, two to four specimens 
of each having been examined: 

Locality Rows Collector 

Winnebago Lake, Wisconsin 110-112 F. C. Baker 

Wainwright Park, Alberta 115 Dr. Swales 

Wainwright Park, Alberta 138-140 Dr. Swales 

Vermilion Lake, Minnesota 140 F. C. Baker 

The material examined for the anatomical data described and figured 
in the preceding pages is listed below. Figures in parenthesis indicate 
number of specimens studied. 

cracuou-^: Winnebago Lake, Wisconsin, collected by F. C. Baker (4) ; Lake 
Nipissing, Ontario, received from the Canadian National Museum (5) ; Mott Lake, 
Wainwright Park, Alberta, collected by Dr. Swales (4) ; 

exacuous megas: Paul Lake, British Columbia, collected by Prof. D. S. Raw- 
son (2). 

umbilicateUus: Mott Lake. Wainwright Park, Alberta, collected by Dr. Swales (8) ; 
North Star Lake, Minnesota, collected by F. C. Baker (1); Vermilion Lake, Minne- 
sota, collected by F. C. Baker (2) . 

Specimens of exacuous from Wainwright Park, Alberta, were heavily 
infested with cercariae, more abundant in the ovotestis and liver. In several 
specimens both of these organs were almost obliterated. 

Geographical Distribution. The genus Promenetus has a wide distri- 
bution. It has been recorded from ]Maine west to Washington and Oregon 
and from Hudson Bay and Alaska south to New JMexico and Alabama. 
A single species {i7nus) is known from Bermuda. 



Species 


Form ula 


exacuous 


17-1-17 


exacuous 


16-1-16 


umhilicatellus 


17-1-17 


umbilicatellus 


18-1-18 



182 The Molluscan Family Planorhidae 

Species Considered as Valid. Five species, in one of which two races 
are recognized, are attributable to Promenetus. 
Promenetus exacuous exacuous (Say) Promenetus rubeUus (Sterki) 

Promenetus exacuous Jtiegas (Dall) Promenetus hudsonicus (Pilsbry) 

Promenetus umbilicatellus (Cockerell) Promenetus imus (Vanatta) 

Geological Distribution. Pliocene to Recent fauna. 

Remarks. Promenetus, first described as a group of the genus Menetus, 
differs so radically from Menetus in the form of the penial gland that 
it is deemed necessary to raise the group to generic rank. Its gland 
resembles Planorbula in the lack of a distinct duct and in the opening of 
the gland which is lengthwise instead of at the end of a cylindrical sac-like 
gland, as in typical Menetus and its subgenus Micromenetus. The form of 
the penial complex is also more like that of Planorbula than like this organ 
in Menetus. In other respects, the genus Promenetus conforms to the gen- 
eral characteristics of the subfamily. 

The discovery that the species long known as Gyraulus umbilicatellus 
is a Menetus closely related to exaciious (Baker, 1935, p. 46) was a surprise 
and shows that the group Promenetus includes species with both rounded 
and sharply carinated whorls. The vas deferens in typical Menetus enlarges 
as it enters the vergic sac to fprm an einphallus. In Promenetus and 
Planorbula, there is no such enlargement. 

Genus MENETUS H. and A. Adams, 1855 
Type designated by D.\ll in 1870, Planorbis opercularis Gould 

1855. Menetus H. and A. Adams, Genera of Rec. Moll., II, p. 262. Includes several 
unrelated species among which is Planorbis opercularis Gould. (Non Menetus 
of Chenu, 1869, P. Fischer, 1883, Tryon, 1884, C. A. Westerlund, 1885, or von 
Martens, 1899) 

1865. Menetus W. G. Bixney, L. and FW. Sh. N. A., II, p. 125. No type cited but 
includes Planorbis opercularis and P. exacuous {== exacutus) . As subgenus of 
Planorbis 

1870. Menetus Tryon, Con. Haid. Mon., pp. 188, 206. Xo type cited but inckides 

both Planorbis opercularis and P. exacutus. As subgenus 
1870. Me7ietus D.\ll, Ann. N. Y. Lye. N. H., IX, p. 351. Type designation, Planorbis 

opercularis Gould. As subgenus 
1886. Menetus Clessix, Syst. Conch. Cab., XVII, p. 33. Type Planorbis opercularis 

Gould. As genus 
1905. Menetus D.^ll. Alaska Moll., pp. 82. 86. Type Planorbis opercularis Gould. 

Section of subgenus Hippeutis Agassiz 
1918. Menetus Walker, Miscel. Pub. Mus. ZooL, Univ. Mich., Xo. 6, pp. 12, 94. Type 

Planorbis opercularis Gould. Section of subgenus Hippeutis Agassiz 
1923. Menetus Wenz, Fossil. Cat.. Pars 22, p. 1650. Genotype Hippeutis (Menetus) 

opercularis (Gould). Few of the .species listed are true members of the genus 

Menetus, which is not found in Europe. They might belong in the genus 

Anisus. Subgenus of genus Hippeutis 
1923. Menetus Germ.mx, Rec. Ind. Mus., XXI, pp. 8, 156. Tvpe Planorbis opercularis 

Gould. As subgenus of Planorbis 
1926. Menetus F. C. Baker, Trans. Wis. Acad. Sci., Arts and Lett., XXII, p. 203. 

T3'pe Planorbis opercularis Gould. Anatomy. As genus 

1928. Menetus F. C. Baker, Fresh-water Moll. Wis., I, p. 360. Type Planorbis oper- 

cularis Gould. Anatomy. As genus 

1929. Menetus J. Henderson, Univ. Col. Studies, XVH, No. 2, pp. 140-141. As sub- 

genus of Planorbis 



Subfamilies, Genera, and Subgenera — Recent and Fossil 183 

1931. Mcnclus Thiele, Handbuch, p. 481. Type Planorbis opercularis Gould. As sec- 
tion under Hippeutis, subgenus of Anisus 

1934. Menctus Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 63. Type Planorbis oper- 

cularis Gould. Anatomy. As genus 

1935. Menetus F. C. B.aker, Nautilus, XLIX, p. 47. Type Planorbis opercularis 

Gould. Anatomy. As genus 

Subgenus MENETUS SS. 

T^■])o Phowrbis opercularis Gould 

Shell (plate 79, figs. 22-24). Small, ultradextral, of few rapidly enlarg- 
ing whorls, the body whorl of large diameter compared wdth the inner 
whorls; right side flat, left side with the spire whorls deeply immersed; 
periphery or shoulder of body whorl more or less carinated ; aperture wide, 
more or less expanded; outer lip usually thin. 

Animal. The foot is comparatively short, the tentacles long and filiform. 
Color generally blackish. In general features the animal is like that of 
Planorhula. 

ANATOMICAL CHARACTERISTICS 

PLATES 38 AND 39 

GENITALIA. Male Organs. [Menetus opercularis, type of the genus, 
plate 38, fig. 1). Seminal vesicle (SV) about 0.5 mm. long, twice the di- 
ameter of the ovisperm duct and about the same length. The vesicle proper 
has a few wide lobes, but the lower part (the ovisperm duct) is lined with 
small vesicles on the side. Sperm duct (SPD) about 1 mm. long, rather 
thick. Prostate (PRS) about 0.5 mm. long with about a dozen main 
diverticula. In section (fig. 2), the prostate shows several small diverticula 
projecting from a single, vertical diverticulum, there being usually five 
branches, one or more of which may be divided two or three times at the 
end (as in figs. 2, 3), or all may be single, long and club-shaped, as in 
cooperi (fig. 14). The vas deferens is 3 mm. long, about half the diameter 
of the sperm duct, and slightly enlarged as it enters the vergic sac. 

The penial complex (fig. 10) is elongated and sac-like, about 1.5 mm. 
long, of which the preputium, narrowed at the male genital opening, 
occupies 1 mm. or two-thirds of its length. There is a slight constriction 
between the preputium and the vergic sac (VS). There is one narrow re- 
tractor muscle (RjNI) attached to the base of the vergic sac. There are four 
sets of supporting muscles (SM) attached to the preputium. Most of these 
are branched several times. 

Internally (fig. 8), the preputium has two pilasters (PL). At the upper 
part of the preputium, there is a short penial gland which is doubled over 
in the normal position (GL). When expanded (fig. 6), this gland is 
trumpet-shaped, the bell-like cup fiaring. The cup cavity is provided with 
vertical folds, as in other Planorbidae. There is a dependent ring or dia- 
phragm between the preputium and the vergic sac cavity (D in fig. 8). The 
verge (V) is elongated and tapering and normally as long as the vergic sac. 

Female Organs (fig. 1). The spermatheca (S) is ovate, about 0.3 mm. 
long and has a very narrow duct (SD) almost 1 mm. long, which enters 
the short and narrow vagina (VG). The uterus (U) is about 0.2 mm. wide 
and 1 mm. long. The oviduct (CD) is very short (about 0.4 nnn.) and 
enters the ovisperm duct without notable decrease in size. There is a large 



184 The MoUuscan Family Planorhidae 

carrefoiir (CF). The albumen gland (fig. 7) is about 1 mm. long and about 
half as wide as long. The vesicles are relatively large. The position of the 
albumen gland in relation to the other organs is shown in fig. 9. 

Hermaphrodite Organs. The ovotestis (OT) is composed of rather 
long, club-shaped diverticula. In section (fig. 5), they are seen to be in 
pairs, unbranched. The ovisperm duct is not free at any portion of its 
length, as is the case in cooperi and c. callioglyptus and other members of 
the Planorbulinae, but is lined with small, rounded vesicles (SO, fig. 1). 

A related, but distinct variety, c. callioglyptus, shows some noteworthy 
differences (plate 39, fig. 1). The seminal vesicle is twice the diameter of 
the ovisperm duct but the vesicles are longer and digitiform (SV). This is 
better shown in a California specimen (fig. 6), where the glands are in 
groups and branched. Rounded swellings or vesicles extend down the ovi- 
sperm duct some distance, but do not cover the entire length as in opcrcu- 
laris. The prostate (PRS) has 15-17 diverticula (see also fig. 13 in plate 38, 
a British Columbia specimen) . In section, the prostate is similar to that of 
opercularis (fig. 3, plate 38) or it may be unbranched, as in fig. 14, plate 
38 (British Columbia specimen). 

The penial complex (plate 38, fig. 11, California specimen) is rather 
broader than that of opercularis, but the relative length of prcputium and 
vergic sac is the same. In specimens from British Columbia (plate 38, fig. 
12; plate 39, fig. 9), there is a decided enlargement at the sunnnit of the 
vergic sac forming an epiphallus (EPI) as in some land snails. This was 
only slightly developed in opercularis (plate 38, fig. 10). There are five sets 
of supporting muscles in a California specimen (plate 38, fig. 11) but a 
lesser number in a specimen from British Columbia (plate 39, fig. 9). There 
is but one retractor muscle (RAI). A jicnial complex from a specimen 
collected in British Columbia, ba(ilv infested with flukes, is shown in fig. 
10, plate 39. 

Internally (plate 39, fig. 7, Menetus cooperi), the preputium has two 
large vertical pilasters (PL). There is a large, sac-like penial gland (GL) 
with a short, narrow, tube-like internal duct (DC) which enters a canal 
in the muscular ring or diaphragm (D). In section (fig. 8), the gland 
shows a shallow cup (OC) at the outer end, lined with many vertical folds. 
A long duct runs through the fleshy part of the gland and connects with 
the short duct which emerges from the base of the gland. The penial gland 
of a Californian specimen of cooperi callioglyptus is shown in fig. 5. 
In this specimen, the gland was bent upward and somewhat contracted. 
The verge (plate 39, fig. 7, V) of cooperi is wide with thick walls. 
In section, it shows a large cavity connecting with the enlarged vas 
deferens (epiphallus) which narrows notably at the entrance of the vas 
deferens (fig. 7, EPI, VD). The end of the verge is shown in fig. 15, plate 
38, indicating the centrally located exit of the sperm canal. The natural 
position of the penial complex beneath the female organs (vagina and 
uterus) is shown in fig. 3, plate 39. In the female organs, the spermatheca 
(plate 39, fig. 1, S) is much elongated and sac-like and the duct is narrow, 
widening somewhat as it enters the vagina. The duct is about as long as the 
spermatheca. The other organs are similar to those of opercularis. 

Pilsbry (1934, p. 64, fig. 7a) figures the penial complex of Menetus 
cooperi callioglyptus (Vanatta) and this is similar to the figures in the 



Suhjamilies, Genera, and Subgenera — Recent and Fossil 185 

present work. The verge is figured rather longer than was observed in 
specimens personally examined, but this organ is variable in form under 
different conditions. The }x^culiar epiphallic enlargement of the vas 
deferens is shown in Pilsbry's figure. The statement that the prostate 
alveoli (diverticula) are in a single series needs emendation, for while they 
ai^pear to be in a single series when viewed in position over the nidamental 
gland, in a cross section they are seen to be composed of several brandies, 
as figured on plate 38 (figs. 2, 3). The diverticula in the natural position 
are hidden beneath the large diverticulum (as in fig. 1 in both plates 38 
and 39) and the series appears simple. 

There is considerable difference between the genitalia of Menetus 
operculaj'is and M. coopcri, particularly in the penial complex, in which the 
form of the penial gland and the size of the eiiiphallus differ. This differ- 
ence indicates that the two forms are distinct species. There is some slight 
variation between specimens from British Columbia and California, but in 
general the anatomical features are similar. 

Respiratory and Renal Systems. The pseudobranch of opercularis is 
wide, somewhat folded or lobed and the rectum extends through the middle, 
the anus opening at the lower edge (plate 38, fig. 4, P, A, R). There is a 
large pneumostome. In cooperi callioglyptus (plate 39, figs. 2, 4), the 
pseudobranch is rounded, somewhat lobed, and with a high ridge extend- 
ing o^'er the length of the rectum (R) and running down the midde of the 
pseudobranch as a low ridge. The anal opening is placed at the left side 
of the pseudobranch. This ridge is also found in opercularis, but is not indi- 
cated in the figure. The two forms of pseudobranch shown in figs. 2 and 4 
on plate 39 indicate the amount of variation that may take place in two 
individuals of the same species. 

The kidney (plate 46, fig. 7) of Menetus cooperi callioglyptus is short 
and very wide (about 2 mm. long and 1 mm. wide). The ureter is a rather 
long, narrow tube reflexed abruptly and directed upward into the mantle 
cavity. The pericardium is about 1 mm. long. The lower part of the kidney 
is very close to the mantle margin, the ureter being in contact with it. A 
cross section of the kidney near the middle (fig. 8) shows the lumen to be 
large, ovate, somewhat wider than high, the vein leading to the pericardium 
much greater in diameter than the renal vein. There is no superposed ridge. 

Digestive System. The stomach region is elongated, the oesophagus 
enlarged to form a crop, the gizzard rounded, and the pyloris rounded and 
diminishing to the intestine which forms a complete loop around the 
stomach, extends backward in the body, makes another loop around the 
liver, and runs forward to the rectum, ending over the pseudobranch. 
There is a long and narrow blind sac or caecum. The stomach region is 
like that of Promenetus exacuous which is figured on plate 48, figs. 4, 5. 

The buccal sac is pyriform, with a large, rounded extension of the 
radula sac at the lower, posterior part. The salivary glands are about twice 
as long as the buccal sac and are much enlarged at the posterior end where 
they are attached, the whole apparatus forming a loop. The oesojihagus is 
enlarged to twice its diameter posterior to the buccal sac. 

The superior jaw of cooperi callioglyptus (plate 50, fig. 7) is arched, the 
ends attenuated. There is a central rounded bulge on the lower margin. 
The jaw is heavily, vertically striated. The side jaws are normal except 



186 The Molluscan Family Planorhidae 

that at the i^oint of attachment to the superior jaw they are bent back- 
ward more than usual. The jaw of Menetus opercularis is similar. 

The radula of Menetus cooperi callioglyptus (plate 67, fig. 3, from 
British Columbia) has a large center tooth, higher than wide, the two wide, 
spade-shaped cusps not reaching the lower border of the base of attach- 
ment. The lateral teeth (1-8) are sciuarish and tricuspid, the cusps long and 
spade-shaped, the mesocone the longest. The intermediate teeth (9-10) are 
narrower than the laterals and have one or two additional cusps above the 
ectocone. The entocone, mesocone, and ectocone become more nearly equal 
in length. The marginal teeth (11-15) are very narrow, elongated, the ento- 
cone is split into from two to four small cusps and the ectocone splits into 
three to four small cusps. The outer marginal teeth are very narrow and 
appear to be serrated with small cusps. The mesocone persists throughout 
the entire series of teeth and may always be identified. 

Data for Radula 

Name Formula Locality Rows Collector 

cooperi callioglyptus 20-1-20 Quatsino, British Columbia 144-145 Mr. Arthur Peake 

cooperi 20-1-20 Orcas Ishmd, Washington 155-161 Dr. T. D. Foster 

The material for the study of Menetus was received from the following 
sources: opercularis from Mountain Lake, near San Francisco, California, 
collected by Mr. H. Walton Clark, two specimens examined; cooperi 
callioglyptus, Quatsino Sound, Vancouver Island, British Columbia, col- 
lected by Mr. Arthur Peake, eleven specimens examined; mill pond at 
Crescent City, California, received from Dr. G. D. Hanna, four specimens 
studied; cooperi, from Orcas Island. Puget Sound, small mountain lake on 
Mt. Constitution, Washington, collected by Dr. T. D. Foster, fifteen 
specimens examined. 

Specimens of cooperi callioglyptus from Quatsino Sound, Vancouver 
Island, were largely infested with cercariae of trematode worms, as many 
as 200 larvae occurring in one specimen. All organs were affected but the 
ovotestis and albumen gland were more often attacked. The parasites 
were most numerous over the stomach region. Specimens of cooperi from 
Orcas Island, Puget Sound, had parasites in liver, ovotestis, albumen 
gland, and over the stomach. In some specimens from both Washington 
and British Columbia all of the organs were obscured by a thick coating 
of mucus. 

Geographical Distribution. Tyjiical Menetus is distributed over the 
Pacific coast region from Vancouver Island south to nortliern California. 
The group does not extend far inland to the east. It is distinctively a genus 
of the coast region. Only a few species are known. Opercularis appears 
to be confined to California, but cooperi (=^ planulatus) is found from 
northern California northward to Vancouver Island, and within this area is 
cjuite variable. There are a number of local forms of limited distribution. 

Species Considered as Valid. The following species and races are at 
present known for the typical subgenus of Menetus. 

Menetus opercularis (Gould) Menetus cooperi callioglyptus (Vanatta) 

Menetus cooperi F. C. Baker, new name Menetus cooperi multilineatus (Vanatta) 

for planulatus Cooper, 1859, not Menetus centervillensis (Tryon) 

planulatus Deshayes, 1824, a fossil 

species. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 187 

Geological Distribution. Pliocene to Recent fauna. Little is definitely 
known concerning the geological ancestry of this genus. 

Remarks. Typical Menetus is a very distinct genus characterized by 
noteworthy anatomical features, chief among which are the sac-like penial 
gland with its short, narrow, internal duct and the epiphallus-like enlarge- 
ment of the vas deferens as it enters the vergic sac. The prostate resembles 
that of Planorbula which has the same structural arrangement of divertic- 
ula. The ovotestis is also like that of Planorbula. The penial gland, how- 
ever, is quite unlike either that of Planorbida or Promenetus. The duct is 
also different . The radula and jaw are like these organs in Promenetus and 
Planorbula. 

Menetus has been subordinated to several groups as a section or sub- 
genus. Thiele phices it under Anisus ( 1931, p. 481 ) , Dall as a section under 
subgenus Hippentis (1905, p. 82), Germain as a subgenus of Planorbis 
(1923, p. 156). Von Martens (1899, p. 390) includes in it species now 
referred to Tropicorbis. The Adams brothers indicated no type, though one 
was definitelv proposed bv Dall in 1870 (p. 351). 

F. C. Baker (1928, p. 360) and Pilsbry (1934, p. 64) have shown 
definitely that the group should rank as a genus. The anatomical figures 
herein published support this conclusion. 

Subgenus MICROMENETUS F. C. Baker, New Subgenus 
Genotype Planorbis dilatatus Gould 

Shell ("plate 79, figs. 13-15) . Very small, ultradextral, of few rapidly enlarg- 
ing whorls ; right side flat or convex, left side with inner whorls submerged 
by the body whorl; body whorl with a more or less well-developed carina, 
usually placed just below the top of the right side; aperture large, some- 
what dilated; lips thin. 

Animal. Foot short, wide, oval on base, bluntly rounded before and 
behind; tentacles long and filiform, enlarged somewhat at base, attaclied 
far back on the head; eyes on small swellings at inner base of tentacles; 
color mottled brown and cream, whole back dark, two black lines extending 
down middle of head; bottom and sides of foot yellowish; tentacles trans- 
parent. Shape of foot varies during locomotion. The shell is carried at an 
angle of thirty to forty-five degrees or it may lie flat on the body of the 
animal. It is seldom carried erect as in Helisoma (plate 70, fig. 9). 

ANATOMICAL CHARACTERISTICS 
PLATE 40 

GENITALIA. Male Organs (fig. 12). Seminal vesicle (SV) of M. dilata- 
tu.s made up of a small number of relatively large vesicles placed on each 
side of the ovisperm duct. Anterior to the seminal vesicle, the ovisperm duct 
is bordered by a number of widely spaced vesicles for a distance three times 
the length of the seminal vesicle. Sperm duct (SPD) of small diameter, 
not much greater than that of the ovisperm duct. The combined free por- 
tion and that part beneath the prostate measure about 1 mm. in length, 
the sperm duct being a trifle longer than the prostate portion. Prostate 
(PRS) with relatively few diverticula, eight or nine. In cross section, the 
prostate shows the same multiplication of smaller diverticula on the under 
side as is present in Menetus opercidaris. In an immature specimen of 



188 The Molluscan Family Planorhidae 

cooperi, the prostate had but five rows of diverticula. The vas deferens is a 
narrow tube ahiiost as long as the sperm duct. It is slightly enlarged near 
the vergic sac. In Menetus sampsoni, the seminal vesicle (fig. 1 ) differs 
from that organ in cooperi in being composed of four rounded swellings. 
Only a few rather large vesicles occur on the ovisperm duct. 

The penial complex (fig. 12) is about 0.5 mm. long, the preputium (PR) 
is sac-like or elongate-pyriform and is about twice as long as the ovate 
vergic sac (VS). In sampsoni (fig. ID, the vergic sac is longer and wider. 
There is one retractor muscle (RM) which is usually attached to the con- 
striction between the preputium and the vergic sac (fig. 11). There are 
several small supporting muscles on both sides of the preputium. The 
penial complex was observed in several different forms in the material 
examined. In one (fig. 3), the vergic sac was placed on the side of the 
preputium, the gland being pushed upward, as occurs so frequently in the 
genus Helisoma. In another specimen (fig. 4) , the preputium was much 
swollen and the retractor muscle was attached to the preputium some dis- 
tance below the vergic sac. 

Internally (fig. 5), there is a sac-like penial gland with a rather long 
duct. This is shown to better advantage in Menetus sampsoni (fig. 10), 
where the gland (GL) is much elongated and gradually diminishes in 
diameter to the round duct, which follows the wall of the preputium (DC) 
to the muscular ring or diaphragm separating the preputial sac from the 
vergic cavity. The cup containing the vertical folds is small and is placed 
at the end of the penial gland. There is a central duct running through 
the gland as in Menetus cooperi callioghjptus. In a Texas specimen (fig. 2) , 
the gland was somewhat different, resembling a pipe or trumpet. This might 
have been abnormal. The verge (fig. 10, V) is elongated, narrowing to a 
point at the lower end. The sperm canal has a central outlet. See also fig. 5. 

Female Organs. The spermatheca (fig. 12, S) is short and sac-like and 
is connected with the very wide vagina (VG) by a wide duct twice as 
long and half as wide as the spermatheca. The uterus (U) is wide, increas- 
ing to about twice the diameter of the vagina in the region of the prostate, 
where the still wider nidamental gland (NG) appears. The oviduct (OD) 
is short and gradually narrows to meet the sperm duct. There is a carre- 
four which lies between the oviduct and the albumen gland (not shown in 
the figure). The albumen gland (AL) is very large and wide (almost half 
as wide as long) and is composed of large vesicles. The intestine makes a 
loop beneath the albumen gland (IN). 

Hermaphrodite Organs. The ovotestis (OT) is composed of relatively 
few large, somewhat club-shaped diverticula arranged in pairs. A single 
diverticulum filled with developing ova is shown in fig. 6. The diverticula 
vary in form, being more swollen when filled with ova ready for discharge. 

Respiratory and Renal Systems, The pseudobranch of dilatatus (plate 
40, figs. 7, 9) is about twice as long as wide and extends below the margin 
of the foot in preserved specimens. It is somewhat folded on the side and in 
a Texas specimen {sampsoni, fig. 8) formed a hollow cylinder. There is a 
fluted crest on the rectum (R) which, however, does not appear on the 
pseudobranch in the specimens examined. The anal opening (A) is jilaced 
at the upper end of the pseudobranch. 



Subfamilies, Genera, and Subgenera — Recent and Fossil 189 

The kidney (fig. 5) is rather short, about 1 mm. long and 0.3 mm. wide. 
The ureter is very long and is folded back tightly against the lower part 
of the kidney. A cross section near the middle of the kidney (fig. 6) shows 
an oblong or ovate lumen with a small vein at each end. There is no super- 
posed ridge. The kidney is wider than that of exacuous but narrower than 
that of cooperi or c. callioglyptus. The pericardium is very wide. 

Digestive System. The digestive system is similar to that of exacuous 
(see plate 48, figs. 4, 5). The radula sac is essentially the same as in 
Menetus. 

The superior jaw (plate 50, fig. 9) of dilatatus is wide and low with 
vertically striated face. The side jaws are as long as the width of the 
superior jaw. The jaws of sampsoni (fig. 6) are similar, but larger. There 
is a slight bulging in the center of the lower cutting edge of the superior 
jaw in both dilatatus and sampsoni. 

The radula (plate 67, fig. 4, dilatatus). Center tooth squarish, not as 
wide as in typical Menetus. Lateral teeth ( 1-7) squarish, tricuspid, the 
mesocone longest, all cusps sharp and spade-shaped. Intermediate teeth 
(8-10) becoming narrower and developing a split entocone and one or two 
small cusps above the ectocone. Marginal teeth (11-14) long and narrow, 
the entocone with three to four small subequal cusps, the ectocone with 
several small cusps on the outer edge of the teeth. The marginal teeth 
become much smaller toward the edge of the membrane. The radula of 
sampsoni is practically of the same type as that of dilatatus (fig. 5). 







Radula Data 






Name 


Formula 


Locality 


Rows 


Collector 


dilatatus 


15-1-15 


Unionville, Connecticut 


125 


F. C. Baker 


dilatatus 


15-1-15 


Hyannis, Alassachusetts 


125 


F. C. Baker 


sampsoni 


15-1-15 


IMerrimec R., Missouri 


125 


Leslie Hubricht 


sampsoni 


15-1-15 


Dallas, Texas 


120 


E. P. Cheatum 



The material examined for anatomical data has been as follows: 
dilatatus, near Unionville, Connecticut, twelve miles west of Hartford, col- 
lected by F. C. Baker (16) ; near Hyannis, Cape Cod, ]\Iassachusetts, 
collected by F. C. Baker (2) ; sampsoni, Merrimec River, near Stanton, 
Franklin County, ^Missouri, collected by Mr. Leslie Hubricht (14) ; small 
creek, six miles northeast of Dallas, Texas, collected by Dr. E. P. Cheatum 
(4) ; slough, near Trinity River, twelve miles southeast of Dallas, Texas, 
collected by Dr. Cheatum (2) ; small lake, near Hutchins, Dallas County, 
Texas, collected by Dr. Cheatum (2). 

The cercariae or rediae of trematode worms were found in some of both 
species of Micromenetus. Of dilatatus, near LTnionville, Connecticut, one 
specimen infested; sampsoni, Merrimec River, Missouri, nearly all speci- 
mens examined, many of the specimens being badly diseased. 

Geographical Distribution. The species belonging to the subgenus 
Micromenetus are distributed over the eastern part of North America 
from Massachusetts west to Iowa and Missouri, and from Maine and 
^Michigan southward to Alabama, Florida, and Texas. It is a group found 
east of the Rocky Mountains. One species, Menetus uliginosus Vanatta. is 
found in Bermuda. 



190 The MoUuscan Family Planorbidae 

Species Considered as Valid. There are several distinct species and 
races of the subgenus Micromenetus recognizable within the genus Menetus, 
as follows: 

Menetus (Micromenetus;) dilatatus Menetus (Micromenetus) alabamerisis 

dilatatus (Gould) aims Pilsbry 

Menetus (Micromenetus) dilatatus penn- Menetus (Micromenetus) brogniartianus 

sylvanicus Pilsbry (Lea) 

Menetus (Micromenetus) dilatatus Menetus (Micromenetus) sampsoni 

buchanensis (Lea) (Ancey) 

Menetus (Micromenetus) alabamensis Menetus (Micromenetus) uliginosus 

alabamensis Pilsbry Vanatta 

Geological Distribution. Not exactly known but certainly from the 
Pliocene to Recent fauna. 

Remarks. The group here separated as Micromenetus differs from 
typical Menetus in the size of the shell which is always much smaller, none 
exceeding 4 mm. in diameter. The form of the shell is lenticular and there 
is usually a peripheral carina more or less well develoiied. The penial gland 
has a duct which is almost three times as long as the gland and is attached 
to the inner wall of the preputium for the greater part of its length (plate 
40, fig. 10). In typical Menetus, this duct is short and enters the diaphragm 
directly without being attached to the wall of the preputium (plate 39, fig. 
7). Tlie pseudobranch in Micromenetus is also very long and narrow 
while in typical Menetus it is short and wide (compare jilate 38, fig. 14, 
with plate 40, fig. 9). These are small differences, perhaps, but they appear 
constant. Micromenetus differs from both Promenetus and Planorbula in 
the shape of the penial gland. As far as examined the radulae of the two 
groups differ in formulae, that of Menetus being 20-1-20 while in Micro- 
menetus it is 15-1-15. 

Genus PLANORBIFEX Pilsbry, 1934 
Type by original designation Planorbis vanvlecki Arnold 

1934. Planorbijex Pilsbry, Proc. Acad. Nat. Sci. Phil., 86, p. 568. Genotype Planorbis 

vanvlecki Arnold. As subgenus of Menetus 

1935. Menetus (Planorbijex) vanvlecki Pilsbry, J. Henderson, Fossil Non-Marine 

Moll. N. A., p. 252. 

Shell (plate 81, fig. 6). Discoidal, dextral in appearance, the right side 
moderately convex, with the last whorl carinate, the periphery rounded; 
left side deeply umbilicate, the last whorl more or less flattened. Sculpture 
of fine, close, hair-like striae. Aperture strongly oblique, its outline excised 
bv the preceding whorl, the receding left margin thickened within 
(Pilsbry) . 

Geological Horizon and Distribution. Basal part of the Tulare forma- 
tion. Pliocene. North dome, Kettleman Hills, Kings County, California. 

Species Considered as Valid. The fossil species Planorbijex vanvlecki 
Arnold, as genotype, is the only species known for this genus. 

Remarks. 'Except for the narrow umbilicus, the absence of a peripheral 
keel, and the thickened peristome, this form resembles Platytaphius 
Pilsbry, a much larger planorb from Lake Titicaca, which has similar 
sculpture. Paraplanorbis Hanna resembles Planorbijex in being small and 



Subfamilies, Genera, and Subgenera — Recent and Fossil 191 

narrowly iinibilicatc, but it has a spire of closely coiled whorls like 
Drepanotrema. The small size and umbilicate left side are like Menetus, 
which, as Arnold thought, is probably its nearest relative; but in carinate 
species of Menetus the keel is peripheral' (Pilsbry, 1934, p. 568). 

'The shell of the type species, Planorbifex vanvlecki, varies in the 
amount of flattening of the base; sometimes it is scarcely noticeable. The 
species was referred by Dr. Cooper to Valvata virens, a very different shell. 
It has certain resemblances to such forms as Valvata bicarinata Lea, but 
the excised outline of the strongly oblique aperture, and the thickened 
peristome, exclude a reference to the Valvatidae, some of which have a 
similar sculpture' (Pilsbry, 1934, p. 569). 

As remarked under the genus Paraplanorbis, it appears better to regard 
Planorbifex as a separate genus related to Menetus rather than as a sub- 
genus of Menetus. The carina in the middle of the whorl of the right side 
is distinctive, and is different from any known species of Menetus or Pro- 
menetus, where the carina is peripheral or just below the margin of the 
left side. 



VIII. 
GROUPS OF UNCERTAIN AFFINITIES 

Subfamily CHOANOMPHALINAE Germain, 1923 
Characters those of the genus Choanomphalus Gerstfeldt 

Genus CHOANOMPHALUS Gerstfeldt, 1859 
Type by original designation, Choanomphalus maacki Gerstfeldt 

1859. Choanomphalus Gerstfeldt, Ueber Land imd Siisswasser-mollusken Siberiens, 
p. 527. Type Choanomphalus maacki Gerstfeldt. As genus 

1870. Choanomphalus Dall, Ann. N. Y. Lye. N. H., IX, pp. 353, 358. Type Choanom- 
phalus maacki Gerstfeldt. As genus 

1875. Choanomphalus W. Dybowski, Die Gasteroi)oden Fauna Baikal-See. Mem. Acad. 
Sci., St. Petersburg, Ser 7, XX, p. 52. Type Choanomphalus maacki Gerst. 
As genus 

1879. Choanomphalus Crosse and Fischer, Jour, de Conch., XXVII, p. 160. Type 
Choanomphalus maacki Gerst. As genus 

1883. Choanomphalus Fischer, Man. de Conch., p. 508. Type Choanomphalus maacki 

Gerst. As genus 

1884. Choanomphalus Tryon, S. and.S. Conch., IH, ji. 105. Type Choanomphahis 

maacki Gerst. As genus 

1885. Choanomphalus Westerlund, Fauna der palaarct. Region Binnenconchylien, V, 

p. 63. Type Choanomphalus maacki Gerst. As genus 

1886. Choanomphalus Clessin, Syst. Conch. Cab., XVII, p. 232. Type Choanompha- 

lus maacki Gerst. As genus 
1909. Choanomphalus Lindholm, Mollusken, in Korotneff, Wissens. Ergebn. Zool. 

Exped. Baikal-See, IV, pp. 8, 93. Type Choanomphalus maacki Gerst. As 

genus 
1923. Choanomphalus Germain, Rec. Ind. Mus., XXI, p. 190. Type Choanomphalus 

maacki Gerst. As genus 
1925. Choanomphalus Dybowski and Grachmalichi, Kosmos, L, p. 877. As genus 
1931. Choanomphalus Thiele, Handbuch, p. 482. Type Choanomphalus maacki Gerst. 

As genus 

Shell (plate 81, figs. 7, 8, 9) small, pseudodextral, turbinate, of few 
whorls rather rapidly increasing in diameter, the spire depressed but not 
flat, base widely umbilicated or with a small chink; aperture rounded. The 
shell resembles some species of Valvata in form. 

Animal. Similar to Plonorbis in tentacles, jaw, and radula. Respiratory 
and genital openings on the left side (see Dybowski and Grachmalichi, p. 
870) . The eggs are laid in capsules with four to five eggs in each capsule. 
The jaws are three in number with a large, half-moon-shaped superior jaw 
and two small lateral jaws. 

The radula plate measures 1.6 mm. in length and 0.3 mm. in width, and 
carries 175 rows of teeth. The formula of Choanomphalus maacki is (4)- 
9-5-16-1-16-5-9- (4) (69 teeth in row) or sixteen lateral teeth, five inter- 
mediate teeth, nine marginal teeth, and four outer marginal teeth without 
distinct form. In Choanomphalus valvatoides the formula is (3) -10-5-10-1- 
10-5-10- (3) (57 teeth in row). In Choanomphalus bicarinatus the formula 
is 4-6-20-1-20-6-4 (61 teeth in row). Choanomphalus cryptomphalus has 
the formula 5-6-20-1-20-6-5 (63 teeth in row). The smallest formula is 
borne by Choanomphalus schrencki which is 4-7-1-7-4 (23 teeth in row), 

192 



Groups of Uncertain Affinities 193 

the outer marginals indistinct and uncountable (op. cit., p. 871). No men- 
tion is made of the cusps of the teeth. There seems to be great uniformity 
in the total number of teeth but some variation in the number of lateral 
teeth. 

The published information concerning the anatomical details is wholly 
insufficient for purposes of classification. 

Geographical Distribution. Lake Baikal, Siberia. The different species 
occur at varying dei)ths, thus maacki occurs at great depths, principally 
between 150 and 350 meters. Valvatoides, on the other hand, occurs in 
comparatively shallow water, from two to ten meters. One species is found 
in the Angara River, near Lake Baikal iamauronicus). Another species is 
found in Japan ( japonicus) . Westerlund includes Europe, Thessalia, be- 
tween Greece an^l Turkey, in the distribution of the genus. This range needs 
confirmation. 

Remarks, The genus Choanoinphalus is a group of mollusks probably 
related to the Planorbidae but of uncertain status as to its proper position 
in the classification of the fresh-water pulmonates. Dall (1870) and Tryon 
(18841 placed the genus, in the subfamily Pompholiginae with Pompholyx 
{Paraphohjx) and Carrriifex. Crosse and Fischer in 1879 compared the 
genus with the American group Carinifex and suggested its group relation- 
ship with the fossil Valvata multiformis { = trochiiormis) . The resemblance 
to Carinifex in both Choanomphalus and the Steinheim fossil itrochi- 
formis) is superficial, Choanomphalus not having the same characteristics 
of anatomy found in Carinifex and Paraphohjx. Westerlund, in 1902 (p. 
120), placed Choanomphalus in the subfamily Planorbinae. 

In 1909, W. A. Lindholm made a study of the Lake Baikal fauna and 
divided Choanomphalus into three subgenera, as noted below. 

1. Choanomphahis Sensu Stricto. Type Choanomphalus maacki Gerstfeldt 

2. Achoaiiomphalus Lindholm. Type Choanomphalus amauronius Bourguignat 

3. Sulcifer Lindholm. Type Choanomphalus schrencki W. Dj-bowski 

The Japanese species is placed in a separate section by Lindholm, 
Choanomphalodes, 1927; type Choanomphalus japonicus Preston. 

Germain (1923) places the group in a subfamily Choanomphalinae. 
Dybowski and Grachmalicki ( 1925, pp. 819-881 ) , in an exhaustive mono- 
graph, review all of the species of Choano))iphalus, some twenty-five in 
number, of which fifteen are considered valid. The peculiar Planorbis para- 
doxus Sturany, from Lake Ochrida near the city of Ochrida, in European 
Turkey, is discussed, but its relationship to Choanomphalus is questioned. 
It has been thought to be related to Choanomphalus by Sturany and other 
European conchologists. It probably represents another peculiar form of 
Planorbidae and its anatomy should be examined. 

The suggestion in the foregoing reference (p. 835), that Segmentina 
may be related to Choanomphalus is obviously erroneous because that 
genus has been shown to be the type of a distinct subfamily not known to 
have any affinities with the Baikal Lake group. A form of Segmentina 
nitida is found in Lake Baikal and is given the name of angarensis by 
these two authors. 

On pages 877 to 880, Dybowski and Grachmalicki present a new ar- 
rangement of Choanomphalus which is made a separate family, Wladis- 
laviidae. Six genera and some twenty-three lesser groups are designated. 



194 The Molluscan Family Planorbidae 

The subgeneric names proposed by Lindholm in 1909 are ignored. These 
six genera, as listed by Thiele (1931, p. 482) with the earlier names of 
Lindholm and the new names proposed by Tomlin for the preoccupied 
names, are tabulated below. 

1. Choa7iomphaIus (SS). Type Choanomphahis maacki Gerst. 

2. Valvatomphalus D. and G. {= Achomwmphalus Lindholm, 1909). Type C. amau- 

ronicus Bourg. 

3. Cryptomphalus D. and G. (non Charpentier, 1837)= Omphalocrypta Tomlin, 1929. 

Tvpe C. cryptoinphahis W. Dybowski 

4. Biangulatiis D. and G. Type Choanomphahis bicarinatus Dybowski 

5. Anomphalus D. and G. (non Meek and Worthen, ISQ^)^ Anomphalodes Tomlin, 

1929. Tvpe C . anomphalus W. Dvbowski 

6. Platybasafis D. and G. {= Sulci) er Lindholm. 1909). Type C. schrc7icki W. Dy- 

bowski 

The value of these generic and group names is debatable. The plate of 
species in the Dybowski and Grachmalicki monograph docs not show 
variation enough to warrant any such minute division, and many of the 
figures suggest individual variation, such as is common among many of our 
North American species of Helisoma. Possibly the few groups and species 
enumerated by Lindholm can be recognized, judging from the figures in 
Fischer's paper (1879, plate 4, figs. 8-10) which are reproduced on my 
plate 81. Just why all of the Lake Baikal species of Choanomphahis should 
not be included in the one genus is not apparent from a study of the shells 
and what little is known about the animals. 

The name Wladislaviidae can not be used because Germain in 1923 
(p. 190) proposed the subfamily name Choanomphalinae two years earlier. 
On this page Germain also questions the value of recognizing subgenera 
for the different species. 

Until the details of the genitalia arc known, particularly the form of 
the ovotestis, prostate, and the internal conditions of the penial complex, 
it will be impossible to determine the true position of this group in the 
classification of the fresh water pulmonates. For the present, the group 
designation of Germain as a subfamily of Planorbidae should be retained. 
It is possible, of course, that when the anatomy is known the group might 
be found to be of family rank, but in that case the name of Germain must 
be used because it was given at an earlier date than Wladislaviidae of 
Dybowski and Grachmalicki. 

Genus POECILOSPIRA :\Iorch, 1853 
Tj'pe by original designation Valimta muUijormis Zeiten 

1853. Poecilospira Morch, Cat. Conch. Yoldi. Type Valvota multiformis Zeiten 

{= Helicites trochiformis Stahl. 1824) 
1879. Poecilospira Crosse and Fischer, Jour, de Conch.. XXVII, p. 160. Type Valvata 

muUijormis Zeiten. As genus 
1884. Poecilospira Tryon. S. and S. Conch., Ill, p. 105. Type Planorhis muUijormis 

(Zeiten). As subgenus of Choanomphahis 

Shell (plate 81, fig. 1). Dextral, varying from fiat with depressed spire, 
discoidal, to trochiform with greatly elevated spire, the last whorl rounded 
and in the same plane as the body whorl or greatly deflected. Whorls 
carinated, the carina placed at the upper side of the whorl in planorboid 
forms and forming a peripheral ridge in the forms with elevated spire. 
Umbilicus large and conspicuous. Aperture round or lunate, entire and 



Groups of Uucertain Affinities 195 

separated from the body whorl, a thick callus on the parietal wall and 
the outer lip thickened in many specimens. 

Horizon and Distribution. ^Miocene period. Steinheim near Heiden- 
heim, Wiirttenberg, Germany. 

Remarks. The planorbid fauna at Steinheim has become classical for 
studies of variation, not only as individuals in a fauna, but also in time 
between the earlier and later strata. Perhaps Hyatt's studies in 1880 (pp. 
1-114, plates 1-9 » are the best known and show in large measure the great 
amount of variation which has taken place during the life of these mollusks 
while the Tertiary strata w^ere being formed in the old lake bed and on its 
shores. Hyatt refers all species to the genus Planorbis. 

In a later paper (1920, pp. 155-216, Taf. 10-12), Gottschick reviews 
what is known concerning the fossils of this locality. He postulated a cold- 
Avater fauna and a warm-water fauna, as we sometimes find in the Pleisto- 
cene faunas of the middle west. This paper is well illustrated and shows the 
great variation in the group of shells known as Planorbis ))iultiformis. 
Wenz (1923, p. 1601 1 includes all of the Steinheim fossils in the genus 
Gyrauhis. The work of Wenz also brings out clearly the fact that the 
fossils of this and nearby regions have been very much overnamed, for 
between 1824 and 1920 no less than forty-five names have been given to 
variations of this group. 

A careful study of the works of Hyatt, Gottschick, and others shows 
that, while many of the so-called species appear to be referable to the 
genus Gyrauhis, the forms grouped around multiformis (trochiformis) 
appear different from the Gyraulus-like shells, approaching Valvata in 
form, and apparently should be segregated in another group. Morch, in 
1863, recognized this difference and gave the assemblage the name of 
Poecilospira. Later authors appear to have overlooked this name which 
does not appear in recent monographs or check lists. It is not mentioned 
by Wenz (1923) in the list of fossils related to trochiformis. 

To what group Poecilospira is related is not definitely clear. It is cer- 
tainly not near Gyraidus and apparently does not belong in the subfamily 
Planorbinae. Also, it is not related to Carinifex or to any of the fossil 
relatives of this group. There are some features in common between 
Poecilospira and Choanomphalus and its true position may be with the 
latter group, as suggested by Tryon in 1884. 



IX. 
FAMILY BULINIDAE 

This group has ahnost universally been considered a subfamily of Planor- 
bidae. It is so treated by Pilsbry (1927, p. 132). More recently several 
authors have considered the group as of family rank, distinct from the 
Planorbidae (Germain, 1931, p. 514; Larambergue, 1939). The shell is of 
Physoid shape but the radula is like that of Planorbis. Two characteristic 
features of the group separate it from any known division of the Planor- 
bidae, the fluted or lobular })seudobranch and the shape of the ]ienial com- 
plex in the genitalia. These are so different that they would appear to be 
characteristics of family rank. The family is mostly exotic, distributed as 
far as known in Australia, Oceania, New Guinea, Celebes, Japan, India, 
the Ethiopian and Malagasy regions, the ^Mediterranean subregion as far 
east as Mesopotamia, and the Antilles (vide Pilsbry, 1927, p. 132). Only 
one species occurs in the Antillcan region. 

The present work was prepared to include only the groups i)roperly 
belonging to the family Planorbidae, but as one species previously referred 
to the Planorbidae has recently been placed in Bulinidae, space is given 
to a discussion of this species and the data for its inclusion in a family to 
which it was not previously believed related. 

Genus INDOPLAXORBIS Aiinandale and Prashad. 1920 
Type by original designation, Planorbis exustus Deshayes 

1920. Iitdoplanorbis Ann.\nd.\le and Pr.\sh.\d, Jour. Med. Res., VIII, p. 112. Type 

Planorbis exustus Deshayes. As genus 

1921. Indoplanorbis Pr.ash.\d, Rec. Ind. Mus., XXII, p. 471. Tvi)p Planorbis cxuslus 

Desh. As genus 

1921. Indoplanorbis Axn.\ni).\le and Pk.\.shad, Roc. Ind. Mus., XXII, p. 578. Type 
Planorbis exustus Desh. As genus 

1921. Planorbis (PUmorbis) exustus Germ.mx, Rec. Ind. Mus., XXI, pp. 26-41. Ex- 

haustive account of variation and .synonymy 

1922. Indoplanorbis Anx.and.\le and Pr.\sh.ad, Rec. Ind. Mus., XXIV. p. 360. Type 

Planorbis exustus Desh. As genus 

1923. Indoplanorbis Rao, Rec. Ind. Mus., XXV, pp. 199-219. Tyi)e Planorbis exustus 

Desh. Description of anatomj'. As genus 
1926. Indoplanorbis Thible, Handbuch, p. 479. T^-pe Planorbis exustus Desh. As 
section of Planorbis 

1933. Indoplanorbis F. C. B.\ker, Jour. Morph., LV, No. 1, pp. 1-12, phite 1-2. Type 

Platwrbis exustus Desh. Account of anatomy, especially genitalia and radula. 
As genus 

1934. Indoplanorbis Pilsbry, Proc. Acad. X'at. Sci. Phil., 86, p. 54. Remarks on 

taxonomic position 
1939. Indoplanorbis exustus Larambergue, Bull. Soc. Zool. de France, LXIV, No. 5, 
pp. 286-295. Anatomy and family position. As genus 

Shell (plate 79, figs. 33-35). Of medium size, sinistral, with few rapidly 
increasing whorls, the body whorl large and greatly increasing in diameter 
toward the aperture; spire whorls flat, depressed below the level of the 
body whorl; base with small umbilical opening, the inner whorls concealed 
by the last two whorls; aperture usually oblique, lips simple, sharp. 

Animal (plate 21, fig. 2). 'The animal is sinistral. Its foot is relatively 
broad and short, leaf-shaped, broadly rounded in front and pointed behind. 

196 



Family Bulinidae 197 

The head is very broad and has its lower margin exi)anded and flattened. 
The tentacles are elongate and filiform. The eyes lie at the inner base of 
the tentacles and are completely sessile. The mouth opens on the lower 
surface of the head in front of the foot' (Annandale and Prashad, 1921, 
p. 578). See Rao. 1923. p. 200, for a more extended account of external 
characteristics. 

ANATOMICAL CHARACTERISTICS 

GENITALIA (plate 21, fig. 3). Male Organs. The seminal vesicle (SV) 
is about 4 nun. long and nearly 1 nun. wide and is composed of small lobes 
or tubercles surrounding the ovisperm duct. The si)erm duct (SPD) is a 
small tube 7 mm. long, the portion near the ovisperm duct folded or coiled. 
The prostate (PRS) is 3.5 mm. long and nearly 2 mm. wide, its low^r end 
broadly rounded, its upper end narrowed to half the diameter of the lower 
lobe. The prostate is composed of many long, branched diverticula, all of 
wdiich radiate fan-wise from the common meeting place of the sperm duct 
and vas deferens. In a cross section near the middle (fig. 8), there are 
shown eight primary diverticula each of which is branched three or four 
times toward the outer end, causing the outer surface of the prostate to 
show twenty-four or more rounded projections. Each diverticulum is 
branched as shown in fig. 9. The sperm duct and vas deferens meet on the 
lower side of the prostate, the prostate diverticula radiating outward from 
this junction. The ])rostate diA'erticula enter the sperm duct from which 
the vas deferens proceeds as a small tube less than half the diameter of 
the sperm duct. This condition is indicated in fig. 10. 

Both Rao and Larambergue describe the prostate as ellipitical in form, 
but it was of the shape figured in all but one of the specimens examined 
and the exception was regularly elliptical. There may, obviously, be some 
variation in the shape of this organ. In its natural position, the prostate 
lies against the uterus below the nidamental gland. The vas deferens is 
a very long, narrow tube (about 12 mm. long). 

The penial complex (fig. 3) is made up of a short, cylindrical preputium 
(3.5 mm. long) and a very long (17 mm.), narrow tube-like vergic sac 
(VS) , which is five times the length of the preputium. In the figure of 
Larambergue (1939, fig. 3, the vergic sac is shown four times the length of 
the preputium. In Rao's figure (1923, p. 215), the vergic sac and the vas 
deferens are confused and the enlarged vergic sac is entirely too short. The 
figure by Larambergue (fig. 1) shows the vergic sac too short and the 
preputium too long as compared with the specimens personally examined. 

There is a single retractor muscle (R^I) attached to the vergic sac near 
the summit of the prejmtium. A heavy nerve (N) innervates this muscle. 
Bands of supporting muscles (SM) are attached to the preputium on both 
sides. In Rao's figure (1923, p. 215), the retractor muscle is shown as at- 
tached to the vergic sac far above the preputium, which position was not 
observed in any specimen examined. Larambcrgue's figure ( 1939, p. 288) 
shows the muscle attached to the vergic sac just above the preputium, 
which appears to be its natural position. 

Internally (plate 21, fig. 1), the preputium contains two long, vertical, 
muscular pads or pilasters (]\IP) which extend the whole length of the 
preputial cavity. There is a small muscular ring or diaphragm between the 
vergic cavity and the preputial cavity. The verge (V) is a very long, nar- 



198 The Molluscan Family Planorhidae 

row tube freely movable within the vergic sac (VS). This organ was en- 
tirely misunderstood by Rao and was not fully comprehended by the writer 
(Baker, 1933). Larambergue (1939, p. 288) correctly figures the relation- 
ship between the vergic sac (poche de penis) and the verge (tube penial), 
the latter being much longer than figured by Baker and extending the 
whole length of the vergic sac. 

The writer figured and described a bulbous swelling within the vergic 
sac (plate 21, fig. 1, B) which was thought to be the termination of the 
verge, the tube behind this swelling being considered as a part of the vas 
deferens. Larambcrgue's figure 2 (reproduced as fig. 2 on plate 73 of this 
work) shows that this is not the case and that the whole tube must be 
considered the verge. However, this bulbous portion of the verge was pres- 
ent in all specimens examined and a swelling of this region is shown in the 
figure of Larambergue where the long line for the symbol pe is directed. 
It seems probable that this bulbous portion (use unknown) is found in all 
examples of Indoplanorhis but in the specimens examined by Larambergue 
there was less contraction than in the specimens examined by Baker. In 
other words, the differences may be attributable to methods of preservation. 

Two specimens examined by Baker had the preputium completely 
everted from the male opening, the sac lying on the body of the animal, as 
shown in fig. 2 of plate 21. One of these specimens is shown in optical sec- 
tion in fig. 7 of plate 22. In this specimen, the preputium was greatly 
flattened so that the pilasters (AIP) became two flattened muscular pads, 
filling the greater part of the preputial cavity. The verge (V) and vergic 
sac (VS) extend through the preputium nearly to the opening of the 
preputium (PR). The bulbous portion of the verge is conspicuous and has 
moved downward. The retractor muscle is attached to the vergic sac near 
its distal end and the large nerve lies beside it (RM, N) . It is clearly 
evident that this muscle pulls back the male intromittent organ after 
copulation. A cross section of the preputium near its widest part is shown 
in fig. 6. The branching of the retractor muscle and the connections of the 
nerve are shown in fig. 5, greatly enlarged. The so-called supporting mus- 
cles of the preputium apparently become retractor muscles when the 
verge and the preputium are everted (fig. 5, plate 21). 

Larambergue (1939, p. 293) describes and figures the penial complex 
in the everted position (see plate 74, fig. 6). The vergic sac is shown ex- 
tended from the everted end of the preputium. The everted copulatory 
organ is enlarged at the distal end, being almost twice the diameter of 
the proximal end near the preputium. A trifle more than half of the length 
of the vergic sac is everted, the shorter portion remaining within the 
preputium and body during eversion. These drawings of Larambergue 
were made from freshly anesthetized specimens taken in coitus. 

Observations on the specimens dissected by the author do not entirely 
agree with those of Larambergue. In several specimens, the verge extended 
from the vergic sac and protruded into the perputium for some distance 
(plate 21, fig. 1). Rao (1923, p. 215) figures the verge (penis) as pro- 
truding from the vergic sac into the preputial cavity. He also figures the 
retractor muscle as attached to the vergic sac and not to the preputium. 

It has been the writer's opinion that only the verge was protruded from 
the end of the preputium when the latter was everted from the male open- 
ing. The retractor muscle is shown by Larambergue as attached to the 
upper end of the preputium, while in all specimens personally examined 



Family Bulimdae 199 

this nmsclc, distally branched, was attached to the end of the vergic sac, 
as shown in plate 22, fig. 7. There are muscles on the preputiiun which 
probably aid in its retraction (plate 21, fig. 5). The writer believes that the 
bulbous swelling (shown at B in fig. 1, plate 21, and at B in fig. 7, plate 
22) has some significance, for it is also shown, although in a more length- 
ened condition, in Larambergue's figure on page 288. It might be that it 
marks the limit of the copulatory portion of the verge, as suggested by 
the writer in a previous paj^er (1933, p. 4). The schematic figures 8 and 9 
in Larambergue's paper (cojiied on plate 74, figs. 8, 9) suggest such a 
condition. As observed by Larambergue, however, these differences may be 
largely due to the preservation of the material examined. 

Female Organs (plate 21, fig. 3). Spermatheca (S) small (about 1 mm. 
long) pyriform, attached to the long, narrow vagina (2 mm. long) by a 
very short duct. The spermatheca is, in fact, almost sessile. The uterus 
(U) is about 5 mm. long and nearly four times as wide as the vagina. The 
large nidamental gland (NG) is 6 mm. long, is about as wide as the 
uterus and is curved about the uterus and oviduct. The oviduct (OD) is 
about as long as the uterus and vagina combined ( about 9 mm. long) . It 
is 1 mm. wide at the uterus end but decreases in diameter toward the 
albumen gland where it joins the sperm duct to form the ovisperm duct. 
There is a small carrefour. The albumen gland (AD, a flattened, more or 
less heart-shaped organ, is convex above and concave below. It has a 
narrow duct which enters the carrefour. The ovisperm duct (SO) is a 
narrow tube about 3 mm. long between the seminal vesicle and the oviduct. 
In the specimens examined it was entirely smooth, but Larambergue 
figures it as having lateral swellings, as was observed in some species of 
Planorbidae. A small, smooth duct about 1 mm. long joins the seminal 
vesicle to the ovotestis. The female organs are as figured in Larambergue's 
paper and also as described by Rao. 

The ovotestis (OT) appears on the surface as a multilobed organ. In 
cross section (near the anterior end) it is seen to be made up of seven 
or more main diverticula which branch twice at the outer end (plate 21, 
fig. 7). They radiate fan-wise from the ovisperm duct. Several branched 
diverticula contained ripe ova at their distal ends. The ova were dark gray 
in color and with these there were several small, rounded bodies which 
were red in color, evidently undeveloped ova. 

Respiratory and Renal Systems. The pseudobranch (figs. 4, 6, plate 
21 ) is large and conspicuous and is not simply folded or leaf-like, as in 
all of the Planorbidae examined, but on the upper and lower surfaces of a 
leaf-like base are developed a number of projections with broad lobes, 
plaits, or folds (fig. 4) groujied together in series of three to six folds, each 
group of folds being separated from the other folds by a distinct depres- 
sion or gap. The base of attachment of the folds is not modified by the 
folded series (see fig. 6). In the living animal, the folded portion of the 
pseudobranch is turned back against the mantle edge. The rectum (R) is 
on the side above the pseudobranch and the anal opening is between the 
pseudobranch and the pneumostome. 

Rao ( 1923, p. 208) describes the lobes as occurring in groups of three 
or four, but in the specimens examined there were two groups of six each 
on the under side of the base and two groups of three lobes and two groups 
of two lobes on the upper side, as shown in fig. 6. The pneumostome (PS) 



200 The Molluscan Family Plauorbidae 

is a large, thin lobe and is capable of considerable extension (fig. 4, PS). 
In fig. 2, it is shown turned back and sjiread open. 

The pseudobranch is highly vascular, well-supplied with blood vessels, 
veins, and muscles. It more nearly resembles the molluscan branchiuni 
than the pseudobranch of any of the other fresh-water pulmonates. 

The kidney is long and narrow (12 mm. long, 1.5 to 3 mm. wide). The 
ureter is 1.5 mm. long and is sharply reflexed against the lower part of the 
kidney, pointing backward and upward into the mantle cavity. In form, 
the kidney resembles that of Helisoma trivolvis figured on plate 44 (fig. 2). 
The reflexed ureter in the s})ecimens examined is not so long as figured by 
Rao ( 1923, p. 206) . A cross section near the middle (plate 45, fig. 19) shows 
a high, thick, wide ridge. The lumen is rounded and shows internal folds 
or septa. A large vein lies on each side of the lumen. The cross section 
somewhat resembles that of the kidney of Planorbarius corneus (plate 45, 
fig. 18). The kidney of Indoplanorbis is noteworthy for the size and width 
of the superposed ridge, which resembles some of the large Hclisotna 
species (as Helisoma pilsbryi, plate 44, fig. 12). 

Digestive System. The stomach resembles that organ in Australorbis 
glabratiis (i)late 48, figs. 9, 10). The intestine first makes a loop around the 
stomach, passes backward to the posterior part of the liver, then makes 
another loop and passes forward to the enlarged rectum, which has its 
exit in the anus above the pseudobranch. There is a narrow, low ridge on 
the rectum which ends near the pseudobranch. There is a large caecum or 
blind sac near the pyloric portion of the stomach. 

The buccal sac is short, wide, and high. Viewed from above, it is 
roughly heart-shaped. The radula sac is represented by a wide, flatly 
rounded bulge at the lower posterior extremity of the buccal sac. The two 
salivary glands are rather long, about one and a half times as long as 
the buccal sac when fully extended. In the natural position, the posterior 
]iortion of tiie salivary glands (somewhat less than half the length) is 
floubled backward beneath the anterior portion, which is wider with larger 
glandular lobules. The ducts are short and narrow. The salivary glands 
are joined behind as in Helisoma and other planorbids. 

The jaws (plate 50, fig. 10) consist of a wide and low superior jaw, 
striated on its outer face, slightly bent downward at the ends. The lateral 
jaws are in the form of a question mark, are very narrow and about as 
long as the width of the superior jaw. The jaws of Indoplanorbis do not 
differ notably from the jaws of the subfamily Helisomatinae. 

The center tooth of the radula (plate 66, fig. 1) is higher than wide, 
rather narrow, the reflection broadly bicuspid and reaching nearly to the 
lower margin of the base of attachment. Lateral teeth (1-5), squarish, 
tricuspid, the mesocone the longest, the ectocone the shortest and i)laced 
high up on the reflection, all cusps wide and spade-shaped. Intermediate 
teeth (6-11) narrower, differing from the typical laterals in having a sec- 
ond small cus]) above the ectocone. The tenth intermediate tooth has two 
small cusps above the ectocone. Marginal teeth ( 12-26) narrow, about 
three times as long as broad. The entocone is split into three to five small, 
subequal cusps, the mesocone is larger and distinct, and the ectocone is 
smaller with two to three small cusps above it on the outer margin of the 
tooth. The outer marginal teeth (27, 32) are still narrower and the lower 
edge of the reflection is minutely denticulated. The extreme outer marginal 
teeth are very small (33) . 



Fcunilij Bulinidae 201 

The nulula formula of Indoplanorbis is 33-1-33 with 140 to 150 rows 
of teetli. There is some variation among the different rows of teeth, prin- 
cipally in the nmiiber of accessory cusps in the marginal teeth. The 
radulae examined were remarkably uniform. The radula figured on plate 
66 agrees with that described by Rao (1923, p. 204). 

The material examined consisted of six specimens from Hsipaw, North 
Shan State, Burma, collected by Dr. B. N. Choi)ra and Dr. H. S. Rao. The 
specimens were received from Dr. B. Prashad of the Zoological Survey of 
India. 

Geographical Distribution. The genus as represented by the type 
species, PUniorbis cxustus Desh., occurs throughout the plains of the 
Indian Empire east of the Indus, in Siam, the Malay Peninsula, French 
Indo-China, and-Sumatra (vide Annandale). For a more detailed account 
of the distribution of this group see Germain (1921, pp. 28, 29). 

The number of species or races referable to Indoplanorbis is in doubt. 
Germain (1921, p. 27) places almost everything under exustus as syno- 
nyms of that species. Planorbis coromandelicus Sowerby and Planorbis 
indicus Clessin have been thought to be distinct by some conchologists. A 
careful study of all names in connection with a large series of specimens 
from various localities might establish several recognizable forms. 

Remarks. The systematic position of Deshayes' Planorbis exustus has 
been a matter of interest for a number of years. It is the largest planorbid 
in India and the shell closely resembles certain species of the American 
genus Helisoma. An examination of its anatomy led Annandale and Pra- 
shad (1920) to consider it a new genus and Rao's investigations (1923) 
strengthened the view of its distinction as a generic group. Baker (1933) 
stated that it was 'one of the most distinct groups of the Planorbidae, its 
male complex exhil^iting characters not shared by any other group at 
present known.' Pilsbry (1934, p. 54) suggests its resemblance to Tropi- 
corbis, particularly in the form of the penial complex. 

]\Iore recently Larambergue (1939, pp. 291, 294) argues that the genus 
Indoplanorbis is a group of the family Bulinidae. Little is known concern- 
ing the anatomy of the majority of the species of this family. Two species 
have been rather carefully studied, Bulinus contortus of Europe by Lar- 
ambergue ( 1939) and Isidora globosa from Portuguese East Africa by 
Connolly. In both of these species, the genitalia are similar to those of 
Indoplanorbis, especially in the form of the penial complex and the pros- 
tate (see plate 71, fig. 3 and plate 75 of this work). The most convincing 
characteristic is the pseudobranch, which is lobed in Bulinidae (Germain, 
1931. p. 514). In Isidora globosa the lobed condition is well shown in Con- 
nolly's figure (plate 71, fig. 5, of this work.) 

The anomaly of a distinctly i^lanorboid shell in a group made up 
almost exclusively of physoid shells is no greater than is shown in the 
American subgenus Seminolina where one species, Helisoma duryi semi- 
nolina, contains all shapes of shell from distinctly physoid to normally 
planorboid. The shell of Indoplanorbis exustus is distinctly sinistral, par- 
ticularly so in the young and immature stages of growth. 

The writer agrees with Larambergue in the statement that the group 
Indoplanorbis is a distinct genus of the family Bulinidae, the deciding 
features being the lobulated pseudobranch and characteristics of the male 
genitalia, particularly the penial complex. 



X. 

GENERA WRONGLY REFERRED 
TO PLANORBIDAE 

Genus NAUTILINUS Mousson, 1872 
Type by original designation, Hyalina clymene Shuttleworth 

1872. Nautilinus Mousson, Neue Denksch. Allg. Schweiz. Gesell., XXV, p. 19. Type 

Hyalina clymene Shuttl. As subgenus of Hyalina 
1921. Nautilinus Thiele, Archiv. fiir Mollusk., LIII, p. 111. Type Hyalina clymene 

Shuttl. Radula and generic position 
1931. Nautilinus Thiele, Handbuch, Teil 2, p. 481. Type A. (N.) clymene (Shuttl.). 

As subgenus of Anisus 

This genus, based on a supposed land snail from Garachico, Tencrife, 
Canary Islands, is scarcely a member of the family Planorbidae, although 
so considered by Thiele. The figures given by Mousson (his plate 1, 
figs. 28-30, natural size, figs. 31-33 enlarged) do resemble some forms of 
Gyraidus. The shell is very small, only 2 nun. in diameter. Tryon (in Man. 
Conch., II, p. 172, 1886) places it in Zonitidae and says 'Its habitat is 
different from the Hyalininae generally, living in wet moss, associated with 
Physa, Ancylus, and Hydrocena, etc' Pilsbry (Man. Conch. IX, p. 24) 
lists it among the land shells. Wollaston (1878, p. 324) says 'I am ex- 
tremely doubtful whether this curious little Planorbis-likc shell should be 
associated with Hyalina.^ 

In 1921 (p. Ill), Thiele extracted a dried radula from a shell of this 
species and briefly described the teeth. The formula is 20-1-20. The center 
tooth is small and has one indistinct cusp. The side teeth (laterals and 
marginals) have four sharp ctisps. The single cusp of the center tooth re- 
moves clymene from the Planorbidae in which the center tooth always has 
two cusps. The form of the shell is distinctly unlike any form of the family 
Lymnaeidae, in which the center tooth of the radula is imicuspid. The 
radula resembles some groups of Ancylidae and Nautilinus might prove to 
be related to this family, perhaps in a similar manner to the American 
genus Neoplanorbis Pilsbry, in which the shell is particularly Planorbis- 
like. Only an examination of the anatomy of the animal, especially the 
genitalia, will definitely settle the question of the taxonomic position of 
Nautilinus. 

Genus PALAEORBIS Beneden and Coemans, 1867 

1867. Palacorbis Beneden and Coemans, Bull. Acad. Belgique, ser. ii, XXII, pp. 385, 
390 

The only recent reference to this group, so far as known to the writer, 
is in Zittel's Grundziige der Palaontologie (Palaozoologie) , Abth. I, In- 
vertebrata, p. 424, w^iere the following comment is made: 'Hierhcr diirfte 
wohl auch die Planorhis sehr ahnliche Gattung; die zierliche Palaeorbis 
Bened. et Coemans em. Reis aus oberkarbonischen und permischen Ab- 
lagerungen von Europa und Nordamerika gehoren.' The name does not 
occur in any other edition of Zittel's work. 

The group is believed to include fossil Vermes, possibly Polychaetes. It 
does not appear to be referable to any mollusk, centainly not to the Pla- 

202 



Genera Wrongly Referred to Planorbidae 203 

norbidae, which are unknown in both the Carboniferous (Mississippian 
and Pennsylvanian) and Permian periods of America. The generic name 
does not appear, as far as known to the writer, in any American work on 
fossil puhnonates. It is j^robable that some Planorbidae will eventually 
be found in Palaeozoic strata, since the family is so well developed in 
Mesozoic time. 



XL 
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TuRTON, W. (1831). A manual of the land and fresh-water shells of the British Islands. 
Pp. viii+150, 16. 10 colored plates. London. 

(1857). A manual of the land and fresh-water shells of the British Islands. 

New edition by J. E. Gray. Pp. xvi+335, 12 colored plates, many text figs. 
London. 

VanCleave, H. J. (1932). Statistical analysis of quantitative collections as a means of 
interpreting life histories. Trans. Illinois St. Acad. Sci., Vol. 24, No. 2, pp. 228-234. 

(1934). The seasonal life history of an amphibious snail, Fossaria modicella, 

living on sandstone cliffs. Ecology, Vol. 16, No. 1. pp. 101-108. 

VanCle.u'E, H. J., and Altringer, D. A. (1937). Studies on the life cycle of Cam- 
peloma rufum. a fresh-water snail. American Nat.. LXXI, pp. 167-184. 

VanCleave, H. J., and Lederer, L. G. (1932). Studies on the life cycle of the snail, 
Viviparus contectoides. Jour. Morph., Vol. 53, No. 3, pp. 499-522. 

W.-iLKER, Bryant (1918). A synopsis of the classification of the fresh-water Mollusca 
of North America, north of Mexico, and a catalogue of the more recently de- 
scribed species, with notes. Miscel. Pub., No. 6, Mus. Zool., L'niv. Michigan, pp. 
213, 1 plate, 233 text figs. 



212 The Molluscan Family Planorbidae 

Ward, Henry B., and Whipple, Geo. C. (1918). Fresh-water Biology. New York. 

(Chapter XIII, Parasitic flatworms, pp. 365-424, by Henry B. Ward.) 
Wenz, W. (1923). Gastropoda extramarina tetiaria. In Fossilium Catalogus I: Ani- 

malio, Pars 22, pp. 1421-1734. Edited by C. Diener. Berlin. 
White, C. A. (1883). The Molluscan fauna of the Truckee group, including a new 

form. Proc. United States Nat. Mus., V, pp. 99-102, plate 5. 
Westerlund, C. a. (1885). Fauna der in der Palaarctischen Region . . . lebenden 

Binnenconchylien. Lund, Fascicle V, pp. 135-|-14. 

(1899). Planorbis libanicus n. sp. Nachrbl. Deutsch. Mai. Ges., pp. 170-171. 

(1902). Methodus dispositionis Conchyliorum extramarinum in regione 

palaearctica viventium, familias, genera, subgenera, et stirpes sistens. Rad. 
Jugoslav. Akad., CLI, pp. 82-139. (1-58). 

WoLLASTON, T. V. (1878). Testacea Atlantica, etc. Pp. xi+588. London. 

Woodward, S. P. (1851-1856). A manual of the Mollusca. Published as follows: Pt. 1, 
pp. 1-158, 1851; Pt. 2. pp. 159-330, 1854; Pt. 3, pp. 331-486, 1856. Several subse- 
quent editions. (Raljih Tate has an appendix in 1869 in which Pompholyx 
appears.) 

Zittel, Ivarl a. von (1910). Grundziige der Paliiontologie (Palaozoologie). I. Abteil- 
ung Invertebrata. Neubearbeitet von Dr. Ferdinand Broili. Munchen und Berlin. 
x4-607 pp., 1414 text figs. 



THE MOLLUSCAN FAMILY PLANORBIDAE 



PART II 

THE PLANORBIDAE INHABITING NORTH AND SOUTH 

AMERICA AND THE WEST INDIES* 



*It was Mr. Baker's plan that Part II should contain full morphological and taxonomic 
descriptions together with comprehensive illustrations of the shells of all species of the 
Planorbidae known for North and South America and the West Indies. His voluminous 
working notes were not near enough objective organization at the time of his death 
to permit their being edited for publication. Any attempt at preparation of these 
notes by another hand could not ensure the reflection of Mr. Baker's matured judg- 
ment and ultimate intent in the casting of specific descriptions, in the portra.yal of 
indi\idual variability, and in the discussion of geographical distribution and ecological 
relationships. However, at the time of his death, he had completed fifty-four of the 
plates intended for this section and had prepared typewritten copy for them. In his 
desk were found plainly-marked photographic prints of other species sufficient to pre- 
pare six additional plates and pencil manuscript for descriptions of the figures had 
been written out. The entire group of sixty plates (82-141) is included as a supplement 
to Part I, even though the six plates at the end of this series represent working copy 
in which he might have desired to make some final alterations. For convenience of 
arrangement and reference, the plates of Parts I and II are presented in a single 
undivided series at the end of this monograph. 

In addition to the plates for Part II, descriptions ha\'e been prepared for nine new 
species and seventeen new varieties. 

The foreword was written by Professor Harley Jones Van Cleave, who also 
assembled and edited the descriptions of the new forms and edited the explanations 
of the plates.— H.E.C. 



XII. 
FOREWORD 

FOR ALMOST A QUARTER OF A CENTURY, Frank Collins Baker 
had been engaged in the preparation of detailed descriptions of the 
species and critical evaluation of the synonymy of the Planorbidae 
of the Western Hemisphere. This study was the natural outgrowth of the 
long years of detailed morphological studies which led him to the evalua- 
tion of anatomical detail as expressed in the broader phases of taxonomy 
in the main body of the present volume. The second volume in this series 
was to have treated the species of the Planorbidae in a manner similar to 
his treatise on another large and important family of fresh-water snails, the 
Lymnaeidae. Though published in 1911, his volume on the Lymnaeidae of 
North and Middle America after more than thirty years still stands as the 
leading taxonomic and distributional study of the lymnaeid snails of the 
Western Hemisphere. 

Though such a program of study involved intimate familiarity with the 
voluminous, scattered literature and wise interpretations of matters of dis- 
puted priority and synonymy, these labors paled into insignificance when 
compared with the self-imposed task of dissecting and microscopically 
studying representatives of all the species available through the well- 
recognized repositories of collections. To these customary sources were 
added large quantities of material from individuals throughout the world 
with whom kindly cooperation had established intimate personal and pro- 
fessional contacts. Large numbers of dissections and long series of shells 
gave opportunity for bridging the gap between the earlier field of Con- 
chology and the newer science of Malacology to both of which Mr. Baker 
had made notable contributions. As he reached final decisions on the 
validity and synonymy of the species in the various genera, he prepared 
photographs of the shells or of original drawings of the type specimens 
wdien shells were not available. These photographs he arranged as plates 
and for each he prepared a detailed descriptive legend. He had com- 
pleted plates illustrating the shells of the genera HeUsoma, Carinijex, 
Parapholyx, Planorhula, Menetus, Drepanotrema, Tropicorbis, and Ta- 
phius. In his office at the time of his death were hundreds of photographic 
prints of other genera and species intended for use in this monograph. 
Some of these he had so marked and keyed with numbers that it has been 
possible to assemble six additional plates which are included at the end of 
the series. With this inclusion, all of the genera which he apparently 
intended to figure are included though many of the species are not por- 
trayed in the detail which he established in those earlier parts which he 
had completed. The explanations of plates 136 to 141 are compiled from 
rough pencil notes and must be accepted as the author's tentative arrange- 
ment of work in progress which might have been changed somewhat in 
the final editing. 

Some of the species not included in the plates of the api:)endix have 
representative shells figured on plates 72 to 81 of the illustrations for the 
body of the monograph. However, these figures are usually of only the 
type species in each genus and do not carry out the plan of comprehensive 
comparisons set for the second section of the monograjih as originally 
projected by the author. 

215 



216 The Molluscan Family Plauorbidae 

In the sixty plates included in this appendix (plates 82 to 141), many 
type specimens and other critically determined materials are figured, and 
information as to the present whereabouts of these critical materials is 
made available. In the members of the family Planorbidae, where syn- 
onymy has been so involved and w^iere intergradations in shell characters 
have been so confusing, the interpretation of range of individual vari- 
ability by one who has devoted years to the study and had the singular 
advantage of access to all the important collections, will be appreciated by 
all naturalists who have the need for studying snails. 

For convenience of reference, the plates in the appendix are numbered 
in direct continuation with the series of plates in the body of the mono- 
graph. In the explanation of the plates, the repository of the figured speci- 
mens is usually indicated by the following abbreviations: 

A.N.S. — Academy of Natural Sciences of Philadelphia 

B. — Frank Colhns Baker Collection 

C.A.S. — California Academy of Sciences 

M.C.Z. — Museum of Comparative Zoology, Harvard University 

U.C. — University of Colorado Museum 

U.I. — University of Illinois, Museum of Natural History 

U.M. — University of Michigan Museum 

U.S.N.M. — United States National Museum 

In connection with the foregoing list of repositories, it should be here 
recorded that the Frank Collins Baker collection of fresh-water snails and 
the specialized library accompanying it, after his death, was deposited in 
the United States National Museum. This was in keeping with his ex- 
pressed desire. It should be further explained that the collections attributed 
to the University of Illinois are designated by two series of letters. Those 
'U.I.' entries having the letter 'Z' preceding the accession numeral are in 
the zoological research collections of the Museum of Natural History in 
the University of Illinois. Paleontological specimens, indicated by inser- 
tion of the letter 'P' immediately before the accession number, are now 
deposited in the Paleontological Collections of the Illinois State Geological 
Survey, in Urbana, Illinois. 

Citations of magnification in the explanation of the plates are usually 
only approximate. In final preparation of the cuts, it was in many in- 
stances unavoidably necessary to make slight modification of the author's 
indicated amount of reduction from the original plates so as to conform 
to the available page size. 

In listing the names of the species in the explanation of plates in the 
appendix, Mr. Baker placed the name of the author of the species imme- 
diately after the specific name and frequently gave no indication by the 
use of parentheses in instances where the si~)ecific name was recombincd 
with a generic name other than that to which the species was originally 
ascribed. It should be recalled that the preliminary draft which he pre- 
pared was never finally edited by him. Through the very generous cooper- 
ation of a number of the most widely recognized American authorities in 
the study of the Mollusca, the use of parentheses for author names has 
been carefully checked. Some errors or inconsistencies may yet be found 
because the literature is extremely scattered and there are no compre- 
hensive check lists of the species of Planorbidae. 

As previously explained, the manuscript for the section in which Mr. 
Baker had expected to provide full descriptions of all species and varieties 



Foreivord 217 

of the Plan()rl)i(l;R' of the New World had never been c()mi)leted. In the 
vohnninous long-hand notes which he left in unfinished fonn, there were 
included the preliminary drafts of descriptions of many new species and 
new varieties intended for incorporation in Part II. After it had been de- 
cided that the plates for Part II should be included as an appendix to the 
morphological studies, it was discovered that the legends for these plates 
made frequent reference to previously unpublished specific and varietal 
names. His manuscript descriptions for many of the new species and new 
varieties were so well organized that there could be no doubt regarding 
his intention. Consequently, liis jireliminary descriptions have been edited 
and are included as a separate section of Part II. A few of the varieties 
and species which he tentatively considered as new could not be found in 
his files. For these it is assumed that he had never prepared definite de- 
scriptions. In order to avoid nomenclatorial difficulties, these names have 
been deleted to prevent their becoming nomina nuda. In each such in- 
stance the undescribed and unnamed form has been referred to under its 
proper genus as a questioned species or questioned variety. 



XIII. 

DESCRIPTIONS OF NEW SPECIES 
AND NEW VARIETIES 

AS EXPLAINED in the foreword, the following technical descriptions 
AA of new species and new varieties were edited from longhand notes 
-*- ■*- prepared by Mr. Baker. During the past quarter of a century he 
examined every important collection of Planorbidae housed in the museums 
of America and received extensive field collections from many private 
collectors as well. In the handling of this huge quantity of material he 
came to recognize fundamental likenesses and differences at vaiying levels. 
In addition to his study of the shells, his intensive work on the morj^hology 
of the snails gave him a broad background for the recognition of natural 
groups. On the one side, he expressed his conclusions in the broad new 
classification of the Planorbidae as set forth in Part I of this volume. 
There he evaluated the characteristics on which families, subfamilies, 
genera, and subgenera may be recognized with safety. On the other side, his 
attention to the limits of individual variation in characteristics of the 
shell furnished the basis for the detailed recognition of specific and varietal 
boundaries. The descriptions of new forms and the redescription of all 
known species were to have been the final goal of Part II of this study. 

From his incomplete notes the following descriptions include only those 
for which he had prepared tentative definitions. On other species and 
varieties, which he obviously thought of as new, he had not committed 
himself through the preparation of manuscript notes and in the assembly 
of illustrations. 

The descriptions of nine new species and seventeen new varieties are 
arranged in the same sequence of genera and subgenera as outlined in 
Part I (see pages xiv and xv of the Contents) . 

All tabular arrangements of shell measurements are expressed in 
millimeters. 

GENUS Tropicorhis 

Tropicorhis shivtieki, New Species 

Plate 134, figs. 12-14, 28 

Shell solid, small, of three and one-half whorls. Upper surface showing 
three and one-half whorls which are subangulate above, sutures very deep. 
Lower surface showing three and one-half whorls which are subangulate in 
the middle, sutures very deep. Whorls rounded on the i)eriphery. Apical 
whorls sunken on both surfaces. Whorl slightly deflected at aperture. 
Aperture Innately rounded, outer lip thick with callus. A callus on parietal 
wall connecting the extremities of the outer lip. Sculpture of coarse growth 
lines with fine spiral lines. Apertural lamellae six, those of sigmoid form 
extremely short and thick, only slightly more than half the length of those 
found in obstructus. 



Shell 
Height 


Greater 
Diameter 


Lesser 
Diameter 


Aperture 
Height 


Aperture 
Diameter 




1.5 
1.6 
1.5 


4.0 

3.8 
3.4 


3.2 
3.1 

2.8 


1.1 
1.1 
1.1 


1.0 
1.1 
1.0 


Holotype 
Paratype 
Paratype 



218 



Descriptions of New Species and Xew Varieties 219 

Type Locality. Ometopc, Nicaragua. 

Type Material. Collected by B. Shimek in 1893. Four specimens de- 
posited in United States National ]\luseum, Accession no. 534290. The 
holotype is shown on plate 134 as fig. 12; figs. 13, 14 are paratypes. 

Tropicorbis shimeki resembles albicans but is smaller, has a greater 
axial height, and has subcarinate whorls. The parietal lamellae are dis- 
tinctly shorter and thicker than in other forms of the genus. T. shimeki is 
smaller than declivis and its axial height is greater; it also has deeper 
sutures than are found in declivis. 

Additional representatives of T. shimeki were collected by Orcutt in 
Coatzocoales, Mexico (United States National Museum, Accession no. 
219696). 

This species is named in honor of Professor B. Shimek. 

GENUS Helisoma 

Helisoma anceps anticostianum, New Variety 

Plate 96, figs. 18-22 

Shell differs from typical anceps in the low axial height, the wide and shal- 
low spire depression with bluntly angular carina, and the shallow and 
wide umbilical region of the new variety. The aperture is but slightly 
expanded. "Whorls about four, evenly and regularly coiled, with faint 



spiral lines. 


Shell 


Greatest 


Aperture 


Aperture 






Height 


Diameter 


Height 


Diajneter 






4.7 


10.0 


3.7 


3.0 


Holotype 




6.0 


12.5 


4.8 


3.6 


Paratype 




4.8 


9.5 


3.7 


2.9 


Para type 



Type Locality. English Bay, Anticosti Island. Quebec, Canada. 

Type Material. Collected by AV. S. Brooks, September 15, 1919. The 
holotype is shown on plate 96 as fig. 18; paratypes as figs. 19 to 22. De- 
posited in the collection of the Museum of Comparative Zoology, Harvard 
University, Accession no. 48285. 

H. anceps anticostianum, a Pleistocene fossil, is similar in appearance 
to striatinum from ^Milwaukee, but differs in the fact that the new variety 
has wider and shallower spire depression, has general lower axial height, 
and lacks distinct angulations above and below. All of these features are 
marked in striatinum. The whorls are likewise flatter above in the new 
form than in striatinum. Spiral lines are not notably distinct. Some speci- 
mens have evidence of a former campanulate lip. 

Helisovna anceps hartschi, New Variety 
Plate 83, figs. 19-22 

Shell compressed, with four whorls. Periphery rounded. Spire depression 
wide, a wide cone with flat sides; shallow, bordered by a well defined 
carina. Base with flattened whorls, the carina sharp and placed near the 
outer edge. Surface of shell shining, growth lines very fine; occasionally 
white varices on whorls. Sculpture of very faint spiral lines. Aperture in- 
verted ear-shaped, forming a sharp V above and a broad V below. Outer 



220 The Molluscan Family Planorbidae 

lip thickened and expanded, white, bordered by reddish band inside. 
Parietal wall with white callus. 

Shell Maximum Aperture Aperture 

Height Diameter Height Diameter 

6.5 11.7 5.5 3.3 Holotvpe 
6.1 12.0 5.1 3.0 Paratvpe 

6.6 11.6 5.5 3.3 Paratype 

Type Locality. Brook at Great Falls, Virginia. Collected by Soelner. 

Type Material. Holotvpe and seven paratypes, deposited in the United 
States National iMuseum, Accession no. 227858. Holotvpe figured on plate 
83, fig. 19; paratypes figs. 20-22. 

This variety may be distinguished by its small axial height, depressed 
shape, wide and shallow spire depression, flat basal whorls with carina 
near periphery. It resembles the variety poUtum from Canada, but that 
variety has rounded basal whorls without marked carina, its spire depres- 
sion is wide with more flat-sided whorls, and dorsal carina is more acute. 
The basal part of the aperture is rounded or almost flat in politum, but has 
sharp, wide angle in bartschi. 

Bartschi differs from sayi in lower axial height, less sharply angled 
basal whorls (with carina not near edge as in sayi) ; shallow and wide 
spire depression. 

Bartschi differs from anceps in lower relative axial height (compared 
with diameter) ; wider spire depression; basal whorls flatter; carina nearer 
periphery (near center in anceps). 

Helisoma anceps bartschi is apparently a common form in the Potomac 

drainage. 

Helisoma anceps idahoense. New Variety 

Plate 84, figs. 26-28 
Plate 101, figs. 11, 12 

Spire with carina in center. Base concave, basal whorls flat to sutures 
which are well marked. Whorls four. Spire depression deep and funnel- 
shaped, the whorls flat-sided. Carina well marked. Whole shell is cone- 
shaped, the whorls sloping upward to the spire carina. Color yellowish horn. 
Sculpture of regular growth ribs crossed by distinct spiral lines. Aperture 
auriform (reversed), sharply angled above, flat or flatly-rounded below. 
Lip sharp. Distinct columellar callus. Color of aperture whitish or slightly 
purplish. A callus often within the lip edge. 



Shell 
Height 


Maximum 
Diameter 


Aperture 
Height 


Aperture 
Diameter 


11.0 

8.5 
9.5 


18.0 
15.6 
15.5 


9.5 
7.5 

8.6 


6.0 
6.0 
6.2 



There is considerable variation in width and depth of spire depression. 
Base rarely rounded, without carina. Carina always near center of base. 
Some variation in shape of aperture. It may form a sharp V below (as in 
the holotype) or it may be rounded and flattened at this point. This- variety 
is nearest to latchfordi, differing in the less angular basal portion of the 
aperture and also in the more distinct and heavier spiral sculpture in 
idahoense. 



Descriptions of New Species and New Varieties 221 

Type Locality. Pend Oreille River, Sand Point, Idaho. 

Type Material. Holotype (plate 84, fig. 26) and paratypes in 
r. C. Baker Collection, no. 1863, now deposited in United States National 
Museum. 

H. anceps idahoense is apparently common in Idaho and Alontana. In 
some places it occurs on muddy sand or on old logs. 

HeXisoTTia anctps ^oliiutn. New Variety 

Plate 83, figs. 16-18 

Shell flattened, ^vider than high, spire deeply sunken, showing three and 
one-half to four whorls, the depression widely cone-shaped rising to a 
vaguely defined, rounded carina. Umbilical region flattenecl, showing three 
and one-half to four whorls, the front half of the body whorl with a faint 
ridge about in the center of the whorl. Ridge disappears on the last third 
of the body whorl which is rounded. Sculpture of fine, thread-like riblets, 
often raised into slight ridges, especially toward the aperture. Color of shell 
pale yellowish to dark brown. Surface polished in living specimens. Fine 
impressed spiral lines present in all specimens examined. Aperture ovate, 
higher than wide, obtusely angled above, straight or but slightly curved 
below. Outer lip thickened, bordered within by a reddish-brown band. The 
lip edge is white on the outside. 



Shell 
Height 


Maximum 
Diameter 


Aperture 
Height 


Aperture 
Diameter 




8.1 

8.1 
8.0 


15.0 
14.0 
14.2 


7.0 
7.0 
7.0 


4:A 

4.0 
4.0 


Holotype 
Paratype 
Paratype 



Type Locality. Honeywell Creek, Carleton Co., Ontario, Canada. Col- 
lected by F. R. Latchford. 

Type Material. Deposited in United States National Museum, Acces- 
sion no. 367426. Holotype figured on plate 83, fig. 16; figs. 17, 18 are 
paratypes. 

H. anceps poUtum is related to unicostatuui but the new variety has 
a wider and shallower spire depression, a more compressed shell, and a 
distinct carina on the basal whorl, besides having the surface of the shell 
ix)lished. Latchford identified this material as unicarinatum. 

Helisoma hinn&yi randolphi, New Variety 

Plate 94, figs. 1-8 

Shell differing from typical binneyi in being of less axial height, the carina 
surrounding the spire depression is obsolete or faintly developed; the basal 
whorls are rounded, not angulated. Sculpture is fine with the ribs close 
together, both being very much finer and closer together than in binneyi. 
The lip is only slightly expanded. ^Mature shells have four whorls. 



Shell 


Maximum 


Aperture 


Aperture 




Height 


Diameter 


Height 


Diameter 




11.8 


20.8 


10"2 


7.3 


Holotype 


11.0 


20.8 


10.3 


6.5 


Paratype 


9.1 


17.1 


8.5 


5.0 


Paratype 


9.2 


15.9 


8.2 


5.5 


Paratype 


7.6 


12.4 


7.0 


4.1 


Immature 



222 The Molluscan Family Plauorbidae 

Type Locality. Lake Wasliington, Seattle, Washington. 

Type Material. Collected by P. B. Randolph, deposited in United States 
National Museum, Shimek Collection, Accession no. 504360. Holotype 
figured on plate 94, fig. 1; paratypes, figs. 2-4; immature, fig. 5. 

Helisoma carihaeum cuhense. New Variety 
Plate 119, figs. 22-25 
Shell differing from that of typical caribaeum in having the spire depres- 
sion much narrower, the whorls, especially the body whorl, increasing 
more rapidly in diameter. Five full whorls. Sutures not impressed as in 
caribaeum, the spire whorls flattened, not rounded, and there is often a 
carina at the edge of the whorls. Nuclear and first whorl rounded as in 
caribaeum and of the same size. Basal whorls rounded, the umbilical 
region concave, umbilical opening distinct. Axial height somewhat greater 
than in typical caribaeum, the body whorl flattened near the spire depres- 
sion, not evenly rounded as in typical caribaeum. Aperture more nearly 
auriculate than in caribaeum, the lip sometimes (as in the holotype) 
thickened by a heavy callus. Sculpture as in caribaeum. 

Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

8.7 19.1 16.0 6.0 4.0* Holotype 

7.0 16.0 13.5 6.2 4.0 Paratvpe 

6.1 14.0 12.0 4.5 3.0 Paratvpe 
6.0 14.1 11.1 4.3 3.1 Paratvpe 

*.A.perture contracted in holotype liy thickened lip. 

The form of the whorls increases like that of tenue, especially like that 
of tenue sinuosum, but inner whorls are like those of caribaeum in that 
they are rounded, and are not like those of tenue which are flat and cari- 
nated at the edges. Some living Cuban specimens have a somewhat nar- 
rower spire than the typical form here figured but these lack the greatly 
increased diameter of the body whorl characteristic of cubense and the 
aperture is not auriculate or thickened by a callus as in mature and nearly 
mature specimens of cubense. The basal whorls are more concave than in 
caribaeum. Sutures are not as deep as in caribaeum. Evidently a Pleisto- 
cene fossil. 

Type Locality. Zapata Swamp, Cuba, in marl between layers of peat. 

Type Material. Eight specimens, collected April 19, 1927, by H. H. 
Bennett, are deposited in the United States National Museum, Accession 
no. 404719. Of these, the holotype is figured on plate 119 as fig. 22, and 
three of the paratypes are shown as figs. 23-25. 

HeXisoma colum\)ie.n&e.. New Species 
Plate 119, figs. 16-21 

Shell with four to four and one-half whorls, rapidlv enlarging. Spire de- 
pression flattened, the inner whorls bordered by a sharp carina which be- 
comes distinctly central in position on the last whorl. The sides of the 
depression slope sharply downward. Base of shell concave, broadly funnel- 
shaped, the last whorl with a more or less sharp carina or ridge. Sutures 
well marked. Sculpture of coarse riblets, widely spaced, as in typical sub- 



Descriptions of Xew Species and New Varieties 



223 



crenatum. Aperture ovately rounded, the li)) riiu thickened and broadly 
reflected. A callus on the parietal wall renders the aperture continuous. 
There is usually. a border of dark chestnut or reddish brown within the 
aperture. The aperture may be rounded above or there may be a sharp 
V-shaped angle, depenfling upon whether the dorsal carina is sharp or 
rounded. There is normally an indication of angulation at this point. The 
basal part of the aperture is flatly rounded. Several old lip expansions may 
show on the body whorl back of the aperture. Color whitish, tinged with 
chestnut in some specimens. 





Shell 














Height 












Shell 


at 


Greater 


Lesser 


Aperture 


Aperture 




ieight* 


Aperture 


Diameter 


Diameter 


Height 


Diameter 




8.5 


10.5 


18.5 


14.6 


8.5 


6.5 


Holotype 


10.0 


10.5 


19.0 


15.5 


9.3 


6.2 


Paratype 


9.5 


11.0 


19.0 


15.5 


10.0 


6.5 


Paratype 


9.5 


10.0 


17.6 


13.6 


9.0 


6.5 


Paratype 


9.1 


11.0 


17.0 


13.1 


8.1 


6.0 


Paratype 



♦Measurement taken behind the expanded lip. 

Type Locality. Lac La Hache, Cariboo District, British Columbia. 

Type Material. Fifteen specimens, collected by H. and R. D. Svihla, 
are deposited in the Museum of Comparative Zoology of Harvard Uni- 
versity, Accession no. 93710. The individual selected as holotype is shown 
on plate 119 as fig. 16; paratypes as figs. 17-21. 

Helisoma columbiense shows relationship to the binneyi group in its 
sculpture and the carination of its whorls. It differs from the members of 
that grou}) in that it is of smaller size, has less relative axial height, its rib 
striae are less widely spaced and the whorls are usually more angulate. 

It differs from the subcrenatum group in having more regular and less 
widely spaced rib striae, in its angulated base and spire depression, and in 
the shape of the aperture. 

Helisoma hennicotti, New Species 

Plate 89, figs. 13-17 

Shell in four whorls, rapidly increasing in diameter. Body whorl axially 
very high. Sculpture of evenly spaced, rather heavy, rib-like growth lines 
becoming more widely spaced on the last half of the body whorls. Spire 
depression concave, widely cone-shaped, flat-sided, bordered by a strong, 
sharp carina, extending to the aperture. Base showing three whorls, the 
umbilicus deep, with a small perforation; only slight indication of a carina 
in adult, but distinct and sharp in immature specimens. Aperture auriform, 
sharply angled above, flatly rounded and effuse below, the outer lip ex- 
panded. Parietal wall with a thin wash of callus which connects the ex- 
tremes of the lip. Color light, yellowing horn, brownish or bluish in some 



specuuens. 




Height 
at 


Diameter 
at 








Shell 


Greater 


Expanded 


Expanded 


Aperture 


Aperture 




Height 


Diameter 


Lip 


Lip 


Height 


Diameter 




12*5 


19.0 


14.2 


20.2 


12.0 


6.6 


Holotype 


12.0 


17.1 


14.0 


18.5 


11.5 


6.5 


Paratype 


12.5 


18.1 


14.2 


19.4 


12.0 


5.5 


Paratype 


7.5 


11.0 


9.0 


12.0 


7.0 


4.0 


Immature 


8.0 


11.0 


9.0 


12.0 


7.0 


4.1 


Immature 



224 The Molluscan Fainily Planorhidae 

Helisoma kennicotti is a very distinct species. It differs from injra- 
carinatum in its smaller size, greater relative axial height, as compared 
with diameter. Expressed in percentages of height to diameter, kennicotti 
is sixty-five per cent and infracarinatum, fifty-six per cent. The spire de- 
pression is much smaller, narrower, and deeper in kennicotti, the shell 
forming an inverted cone. The base of the new species is likewise narrower, 
and the whorls dip into the umbilicus at a sharper angle, only one and 
one-half turns before entering the umbilicus. In contrast, in infracarinatum 
tliere are two full turns visible. 

Type Locality. Lake Isle la Crosse, English River, Canada. 

Type Material. Deposited in United States National Museum, Acces- 
sion no. 29231, bearing the label of the old Binney collection no. 9272 and 
there recorded as Planorbis trivolvis. Figures on jilate 89; holotype as 
fig. 15; paratypes as figs. 16, 17; 13, 14 immature shells. 

Helisoma pilshryi prehlei. New Variety 

Plato 91, figs. 6 to 8 

Helisoma pilsbryi prehlei differs from typical pilsbryi in its greater relative 
height in comparison with diameter of the shell. The whorls in prehlei are 
more tightly coiled, the body whorl increasing more rapidly in diameter, 
causing the spire depression and umbilical region to appear smaller than 
in pilsbryi in which the whorls are rounded more regularly. The aperture 
is widely expanded to form a reflected lip. This is not true of pilsbryi. 
Whorls, four and one-half. Sculpture as in pilsbryi. H. p. preblei differs 
from subcrenatum in absence of all indication of a carina on the umbilical 
side. The whorls of the spire depression are subangulated, not sharply 
angled as in infracarinatum. 

Height Diameter 

at at 

Expanded Expanded 

Lip Lip 

17.0 27.0 

16.0 26.0 

*Bioken specimen with four and one-fourth whorls, the last one-half whorl broken away. 

Type Locality. Knee Lake, Manitoba, Canada. 

Type Material. Three specimens, collected by E. A. Preble in the 'North 
West Territory, Knee Lake, Keewatin,' deposited in United States National 
Museum, Accession no. 180279. Figured on plate 91, holotype as fig. 6; 
paratypes as figs. 7, 8. 

The type material was i:)reviously called infracarinatum but it is nearer 
to pilsbryi. It differs from the latter in its expanded lip and more tightly 
coiled whorls of the umbilical region. Differs from infracarinatum in the 
absence of a basal carina and in having a narrower and more sunken 
spire depression. 

Helisoma subcrenatum perdisjunctum^. New Variety 

Plate 96, figs. 13-17 

Shell small, horn colored; whorls three and one-half to four, discoidal, 
evenly rounded; 3 whorls below. Whorls slowly increasing in diameter, 
rounded above and below, not carinated. Sculpture of distinct growth lines, 



Shell 


Greater 


Height 


Diameter 


14.0 


24.5 


14.0 


25.0 


11.5 


19.0 



Aperture 
Height 


Aperture 
Diameter 




13.0 

13.0 

9.5 


7.0 
7.5 
5.6 


Holotype 
Paratype 
Paratype' 



Descriptions of Xeiv Species and Xeiv Varieties 225 

finer than in disjunctum. Aperture rounded above and below, slightly ex- 
panded where it joins the body whorl. A distinct callus on the parietal wall, 
often making the aperture and lip continuous. A slight thickening inside 
outer lip, bordered by brown band. 



Shell 


Greater 


Aperture 


Aperture 


Number 




{eight 


Diameter 


Height 


Diameter 


of Whorls 




4.0 


8.5 


3.7 


2.6 


4.0 


Holotype 


4.6 


9.2 


4.1 


3.0 


3M 


Paratype 


5.0 


9.0 


4.7 


3.2 


3M 


Paratype 


5.2 


10.5 


4.9 


3.2 


4.0 


Paratype 



Type Locality. Yellowstone Lake, Wyoming. 

Type Material. Five specimens, collected by Dr. Curtis, deposited in 
the United States National Museum, Accession no. 30207a. Holotype here 
shown as fig. 13 on plate 96; paratypes as figs. 14-17 on same plate. 

H. s. per disjunctum is similar to disjunctum but is much smaller, about 
the size of oregonense, but lacks the characteristic shape of the aperture of 
the last named form. The dorsal carina and the more uniformly and evenly 
coiled whorls, without rapid increase in size distinguish it from oregonense. 
Appears at first like immature disjunctum but is uniformly smaller; never 
has the axial height of disjunctum. ]\Iany specimens have lost the epi- 
dermis, exposing white, chalky shell. 

HelisoTTia trivolvis marshalli, New Variety 

Plate 87, fig.s. 11-15 

Shell compressed, whorls four and one-half, rapidly increasing in diameter, 
the body whorl notably expanding toward the aperture. Sutures well 
marked above and below. Sculpture of coarse lines of growth, thread-like; 
spiral lines very indistinct or wanting. Spire depression small, narrow, 
shallow (less than one-half the width of whorl) , its border rounded, with- 
out carina in adult specimens, carina slightly developed in young and 
immature specimens. Spire flat in young individuals. Ventral surface flat- 
tened, the whorls coiled in one plane in mature specimens, three whorls 
visible, the umbilical whorls with a more or less acute carina. Sutures deep. 
In young and immature individuals the carina is sharp and the basal whorl 
about the umbilicus is raised to form an inverted V; whorls rounded ven- 
trally in half grown and immature specimens. Aperture wider than high, 
long oval, the dorsal margin forming an inverted V near junction with body 
whorls; the ventral margin flat, straight, extending well beyond the position 
of the dorsal margin on the body whorl. Outer lip sharp, with slight thick- 
ening within, margined by reddish line. Surface of shell light or dark horn. 



Shell 


Greater 


Lesser 


Aperture 


Aperture 




Height 


Diameter 


Diameter 


Height 


Diameter 




5.9 


14.8 


11.5 


5.0 


4.7 


Holotype 


6.0 


13.0 


10.8 


5.0 


4.1 


Paratype 


5.8 


14.0 


11.9 


4.9 


4.5 


Paratype 


5.4 


11.0 


8.6 


4.8 


3.5 


Immature 


4.9 


10.2 


8.0 


4.2 


3.3 


Immature 



Helisoma trivolvis marshalli differs from jallax in that the new variety 
has the body whorls more expanded toward the aperture; the dorsal de- 
pression is smaller; color is light or dark horn, not greenish; the aperture 
is wider and more ovate. 



226 The Molluscan Family Planorbidae 

Type Locality. Washington, D. C. 

Type Material. Collected by Foreman, deposited in United States 
National Museum, Accession no. 124989. Holotype on plate 87 as fig. 13; 
paratypes as figs. 11 and 12; figs. 14 and 15 of immature shells. 

In addition to the type locality, H. t. marshalli has been identified in 
collections from various localities in Maryland, New York, New Jersey, 
and Virginia. 

HelisoTTia campanulatuTn dalli, New Variety 
Plate 111, fifis. 12. 13, 15, 16 

Shell resembling michiganense in the low axial height, but the body whorl 
is irregularly coiled and overlaps the penultimate whorl. Five whorls, upper 
whorls irregular; blunt carina on upper whorls. Four whorls showing on 
base, base 'reamed out' similar to that of rudentis, and whorls irregular. 
Umbilicus much smaller than in rudentis and also smaller than in michi- 
ganense. Lower whorls rounded. Sculpture and aperture as in michiganense. 

Shell Maximum Lesser Aperture Aperture 
Height Diameter Diameter Height Diameter 



6.2 


15.0 


11.6 


5.5 


4.0 


Holotype 


5.4 


14.1 


11.0 


4.7 


4.0 


Paratype 


5.5 


14.1 


11.5 


5.0 


3.6 


Paratype 


6.1 


14.9 


11.6 


5.3 


4.0 


Paratype 



Type Locality. Anticosti Island, Quebec, Canada. 

Type Material. Collected by Dr. J. Schmitt, deposited in United States 
National Museum, Accession no. 162724. Holotype, plate 111, fig. 12; para- 
types, figs. 13, 15, 16, five others not figured. 

Differs from other varieties in irregularly coiled body whorl which con- 
spicuously overlaps the preceding whorls. Base is not excavated, but whorls 
are irregularly coiled as in spire. Axial height less than in rudentis. 

Helisoma cainponidatu))i dalli is known only from marl deposits. 

Helisoma campanulatum pleistocenicmn, New Variety 
Plate 110, figs. 21-26 

Shell small, whorls four, the inner spire whorls tightly coiled and gradually 
increasing in diameter, the last whorl rapidly increasing in diameter. The 
spire depression occupies about thirty per cent of the greater diameter of 
the shell while in campanulatum campanidatum it occupies about forty 
per cent of the greater diameter of the shell. Sutures w^ell impressed. Base 
with two to two and one-half whorls visible, the whorls tumid. Umbilicus 
large for the size of the shell. Aperture strongly cami^anulate, the campanu- 
lation beginning a considerable distance back of the aperture. 

The small diameter of the spire depression and the rapidly enlarging 
body whorl serve to distinguish this variety from all other forms of 
campanulatum. This form is distinctly different from the Pleistocene cayn- 
panidatum of the middle west. 

Type Locality. White Pond, ]\Iarlsboro, Warren Co., New Jersey. 

Type Material. Holotype (figured on plate 110, fig. 21) and eight para- 
types (five shown on plate 110, figs. 22-26) are in the Lea Collection in 
the United States National Museum, Accession no. 121195. 



Descriptions of Neiv Species and N'eiv Varieties 227 

Helisoma campanulatum rideauense. New Variety- 
Plat (> 109, fig.^. 21-24 

Shell very large, of five whorls, spire flattened, the inner whorls raised 
slightly above the body whorl; sutures deeply marked. Base with three 
to four whorls visible, rounded, in same plane, not reamed out as in dalli 
and rudentis; sutures well marked and whorls rounded. Umbilicus small, 
deep. Aperture as in campanulatum. Sculpture of heavy, evenly spaced 
riblets, but not as heavy as in wisconsinense ; about as in some individual 
shells of ca»ipanulatiuu. In the following table the measurements were 
taken just behind the aperture, which is constricted and then dilated. 



Shell 
Height 


Greater 
Diameter 


Lesser 
Diameter 


Aperture 
Height 


Aperture 
Diameter 




6.5 
7.0 
7.0 

6.8 


19.6 
18.5 
18.0 
17.5 


15.0 
14.1 
14.0 
13.0 


6.5 
6.5 
6.3 
6.3 


6.0 
5.1 
5.1 
5.4 


Holotype 
Paratype 
Paratype 
Paratype 



H. c. rideauense differs from michiganense in the former's larger size, 
smaller umbilical opening, and greater axial height. Surface is dull, not 
shiny, caused by the heavy scul]:)ture. Color bright horn. The aperture is 
more distinctly campanulate than in michiganense . 

Type Locality. Rideau River, Ottawa, Canada. 

Type Material. Five specimens, collected by F. R. Latchford, deposited 
in the United States National ]\Iuseum, Accession no. 346627. Tlie holotype 
is shown on plate 109, fig. 21 ; paratypes, figs. 22-24. 

GENUS Farapholyx 

Parapholyx effusa dalli. New Variety 

Plate 115, figs. 27-30 

Three whorls, rounded. Color greenish horn. Spire slightly raised, sutures 
well marked, deep on last whorl. Sculpture of strong, erect, membranous 
ribs, thirteen to fifteen on body whorl, equidistant or widely spaced. Very 
fine lines of growth between ribs, spiral lines obsolete. Ribs usually absent 
on spire whorls. The ribs produce spaced, vertical depressions inside aper- 
ture. Aperture rounded, acute below. Columella narrow, concave, either 
contpletely closing the umbilicus or leaving a small narrow and long chink. 
A thin wash of callus on the parietal wall. 

Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

4.9 5.0 4.8 3.9 3.3 Holotype 

5.0 5.0 5.0 4.0 3.3 Paratype 

5.0 6.0 5.0 4.1 3.2 Paratype 

Parapholyx effusa dalli differs from all other forms of the genus in the 
presence of membranous ribs which stand up, either at an angle or verti- 
cally, as leaf-like frills, very thin and easily broken off. The ribs in costata 
and other costate forms of the genus (as costate specimens of klamath- 
ensis from Klamath Falls) are simply rounded ribs, enlargements of the 
lines of growth. These do not affect the inside of the aperture. In dalli, on 
the contrary, the ribs appear as vertical creases on the inside of the aper- 



228 The Molluscan Family Planorbidae 

ture. Some individuals of costata may have slightly membranous ribs, but 
these are never like those of dalli. 

Type Locality. Klamath Falls, Oregon. 

Type Material. Seventeen specimens, collected by Henshaw, are de- 
posited in the United States National Museum, Accession no. 219749. The 
holotype is figured on plate 115 as fig. 27; paratypes as figs. 28-30. 

Parapholyx klamathensis sinitsini, New Variety 
Plate 123, lig.^. 2-10 

Shell similar to that of klamathensis but smaller, more globose; the shell 
thicker and more solid. Spire more elevated than in typical klamathensis; 
aperture rounder, not as effuse; columella callus heavier, more tightly ap- 
pressed to the columella. The umbilicus usually closed, rarely having a 
small chink. Color brownish horn, never greenish. Sculpture heavier than in 
klamathensis, growth lines more distinct, in a few specimens rib-like. In- 
terior of aperture reddish-brown. Lip bordered internally by a white 
margin which in old specimens forms a thickened callus. In contrast, 
klamathensis of typical variety has a thin lip without a callus. Columellar 
callus white. Whorls three. Some specimens with diagonal markings like 
pores. Aperture angulate below, as in klamathensis, but not markedly 
angular in some specimens. 



Shell 


Greater 


Lesser 


Aperture 


Aperture 




Height 


Diameter 


Diameter 


Height 


Diameter 




6.4 


7.0 


5.0 


4.5 


4.0 


Holotype 


5.6 


7.1 


4.4 


4.3 


4.3 


Paratype 


7.1 


8.2 


6.0 


5.0 


4.8 


Paratype 


5.6 


6.8 


4.5 


4.0 


3.6 


Paratype 


5.6 


6.6 


5.4 


3.8 


3.8 


Paratype 



Type Locality. Bercley Spring, fourteen miles north of Klamath Falls, 
Oregon. 

Type Material. Five specimens, of which one is designated as holotype 
and the four others as paratypes, are deposited in the United States 
National Museum, Accession no. 531029. The holotype is shown on plate 
123 as fig. 2; two paratypes on the same plate as figs. 3 and 4. A series 
of specimens from the same locality, collected by Mrs. L. Sinitsin, are 
accessioned in the United States National Museum, no. 531064. The indi- 
viduals of this last named series are designated as locotypes of the new 
variety. 

Parapholyx kla))iathensis sinitsini is a form smaller than the tyjucal 
klamathensis. The two forms have the same columella and angular base 
of aperture. The new variety has a higher spire than the typical form and 
the shell is more globose. Some individuals wdth diagonal ridges resemble 
diagonalis from Crater Lake but in that form the columella is wider, more 
concave and flatter and the aperture is more effuse. The spire of the new 
variety varies from flat to elevated depending upon the deflection of the 
aperture. Sinitsini has about the same size as Parapholyx solida optima 
but that form has a flat spire and a different aperture, especially in the 
region of the columella. 

This variety is named for Mrs. L. Sinitsin. 



Descriptions of Xew Species and A^eiv Varieties 229 

Parapholyx pusilla. New Species 
Plate 117, fijis. 1-6 

Shell small, with three whorls, scalariform, the second whorl standing on 
the body, turban-shaped; sutures distinct. Aperture roundly ovate, lips 
simple, lower lip rounded at base. Columella callus narrow, not expanded, 
separated from the columella region where it often projects leaving a dis- 
tinct umbilical chink. Aperture continuous by the presence of a parietal 
callus. Sculpture coarse, often costate. 

Shell Maximum Aperture Aperture 

Height Diameter Height Diameter 

4.0 5.0 2.3 2.3 Holotvpe 

4.5 4.3 2.5 2.1 Paratvpe 

4.5 4.5 2.4 2.4 Paratvpe 

Type Locality. Six miles west of Pyramid Lake, Washoe County, 
Nevada. 

Type Material. One hundred twenty-five specimens taken from a Pleis- 
tocene deposit by Elbert Howard^ are deposited in the United States 
National Museum, Accession no. 308925. The individual from this lot 
chosen as holotype is shown on plate 117 as fig. 1. Figures 2 to 5 on the 
same plate are of paratypes. 

Parapholyx pusilla differs from Parapholyx rievadensis in that the 
new species has a more rounded shell, with elevated and turban-shaped 
second whorl and the lower portion of the aperture lacks the sharp angle 
caused by the columcllar callus in Jievadensis. The new species differs 
from P. solida in the form of the spire, aperture and base of lip. 

This is apparently an extinct sj^ecies. 

GENUS Planorhula 

Planorhula smithii. New Species 

Plate 118, figs. 11-12; plate 119, figs. 10-12 

Shell resembling that of wheatleyi but larger, of five whorls, the spire 
whorls in the same plane and not so sunken toward the nucleus as in 
wheatleyi; no dorsal ridge as is developed in wheatleyi; umbilical opening 
wdth the whorls rounded, not flat sided and without the sharp carina dis- 
tinctive of wheatleyi. Crest behind aperture not as heavy or as thickened 
as in ivheatleyi. Sculpture of distinct spiral lines. Apertural lamellae as in 
armigcra not as in wheatleyi. 

Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

3.0 7.1 5.5 2.0 1.3 Holotvpe 

2.8 7.0 5.0 1.7 1.0 Paratvpe 

2.9 6.9 5.8 1.5 1.0 Paratype 

Type Locality. Jackson County. Alabama. 

Type Material. Fifteen specimens, collected by H. H. Smith, are de- 
positee! in the United States National Museum, Accession no. 321196. The 
holotype is figured on plate 119. as fig. 10; jiaratyjies on the same plate 
as figs. 11 and 12. 

Externally Planorhula smithii resembles wheatleyi but the newly recog- 
nized species is readily distinguishable by the absence of the L-shaped 



230 The Molluscan Fa7nily Planorhidae 

second labial lamella. Smithii is larger than crassilabris and has a much 
heavier lip callus. It somewhat resembles indianensis but lacks the axial 
height of that race and the latter also lacks the lip callus of smithii. 
Planorhula smithii is named for Herbert H. Smith. 

GENUS Menetus 

Menetus coloradoensis, New Species 

Plate 122, figs. 23-25 

Shell acutely lenticular, flattened, with three whorls. Color blackish brown. 
A rounded carina on the periphery which is impressed both above and 
below the periphery a short distance from the edge. The carina is not acute 
(excepting in immature specimens) but is bluntly rounded. Upper surface 
flattened, with deeply inpressed sutures. The whorls tumid near the sutures. 
Base convex near the suture but flattened toward the periphery. Basal 
whorls separated by deep sutures. Sculpture ranging from coarse growth 
lines to evenly spaced ribs, spiral lines very fine. Some specimens begin 
with coarse growth lines and end with ribs. Aperture triangular, upper 
and lower lips arching downward and upward to meet the periphery which 
is not sharp but is narrowly rounded. Upper lip projects just above the 
periphery and is flat, but lower lip has a long columellar region and is 
convex. Aperture much wider than high, jmrplish within and somewhat 
pearly. Umbilicus rather wide and deep. 

Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

1.0 1.6 Holotype 

0.9 1.8 Paratype 

0.9 1.5 Paratype 

Type Locality. Swamp at head of Eldora Lake, near Eldora, Colorado. 

Type Material. Deposited in the University of Colorado ALiseum, Ac- 
cession no. 10114. Holotype shown as fig. 25 on plate 122; two paratypes 
as figs. 23 and 24 on same plate. 

Menetus coloradoensis differs from eracuous in the pinched nature of 
the periphery, the swollen or tumid base near the suture, and the heavy 
(in some instances, costate) sculpture. Menetus exacuous megas has a 
pinched periphery, but in this variety the base and sculpture are as in 
typical exacuous. The new species is nearest to kansasensis but differs in 
having a more tumid base and a different type of rib-sculpture. 

Menetus cooper i crassilabris. New Variety 
Plate 121, figs. 19-21; plate 122, fig. 13; plate 123, fig. 26 

Specimens like cooperi but with heavy callus just within lip. Shell of four 
whorls. Heavy spiral sculpture. Whorls usually rounded but with slight 
indication of carina at shoulder as in cooperi. Several spiral ridges below 
shoulder, and base often malleated as in cooperi. Umbilicus with rounded 
edges. Aperture rounded, not usually modified by carina. Most shells are 
smaller than cooperi. 

Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 
2.1 5.4 4.0 1.6 2.0 Holotype 



1.1 


4.0 


3.6 


1.0 


4.6 


4.0 


1.0 


4.1 


3.6 



Descriptions of New Species and New Varieties 231 

Type Locality. Seattle, Washington. 

Type Material. Twenty-four specimens are in the United States Na- 
tional Museum bearing Accession no. 214590, one of which is selected as 
holotype and the remaining specimens become paratypes. Holotype is 
shown on plate 121 as fig. 20; and one paratype as fig. 19. 

Of the twenty-four specimens in the type lot all but one had a callus, 
this one being doubtfully referred to cooperi. The original labels of some 
lots in the National Museum carried identification as oregonensis. Evi- 
dently this was based upon the presence of a lip callus. However, cras- 
silabris lacks a peripheral carina and cannot be allied with oregonensis. 
Other collections have been determined as centervillensis, but the umbili- 
cus is distinctly different in crassilabris. 

Menetus cooperi crassilabris has been identified in collections from 
Colma, San Mateo County, California; Oakland, California; Portland, 
Oregon; Lake Washington at Seattle, Washington; and mountain swamps 
at Olga, W^ashington. The last named were erroneously identified as 
Menetus cooperi calioglyptus. One collection from Oakland was associated 
with typical cooperi. 

Menetus cooperi planospirus, New Variety 

Plate 122, figs. 3-6 

Shell with three whorls, of yellowish horn color. Upper surface flat, the 
whorl bordered by a raised revolving ridge at the edge. Spire whorls 
sunken below general level. Base convex. Umbilicus deep, about one-fourth 
the diameter of the shell. Peripheral ridge stands out and elevated above 
the shell as a cord. Aperture modified by carina. Sculpture of rather coarse 
growth lines, crossed by heavy spiral lines. 

Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

3.0 3.0 Holotype 

2.6 3.0 Paratype 

2.0 2.0 Paratype 

2.2 2.4 Paratype 

Type Locality. Orcas Island, Puget Sound, Washington. 

Type Material. A collection of thirty-six specimens, taken by W. H. 
Souther, is deposited in the Museum of Comparative Zoology, Harvard 
University, Accession no. 31583. One of these, designated as holotype, is 
shown on plate 122 as fig. 5, and three paratypes are shown on the same 
plate as figs. 3, 4, and 6. 

Menetus cooperi planospirus is characterized by its very flat spire and 
the presence of a raised carina placed at the upper edge of the whorl. It 
differs from Menetus cooperi multilineatus in the position of the carina, 
and in having a flat rather than a convex spire. 

Menetus dalli. New Species 
Plate 140, figs. 22-24 

Shell small, lenticular, with a bluntly angular periphery. Upper surface 
flatly convex, three whorls visible, sutures deeply incised. Lower sur- 
face flatly convex, the umbilical or spire region small, occupying one-sixth 
of the diameter of the shell. The lower surface is swollen over the umbili- 



3.3 


8.0 


7.0 


3.0 


6. .5 


5.6 


2.6 


5.9 


5.0 


2.5 


5.9 


5.0 



.5 


4.0 


3.2 


.4 


3.2 


2.7 


2 


2.9 


2.2 



232 The Molluscan Family Planorbidae 

cus. The lower surface has a somewhat pinched appearance, with an 
indistinct, impressed Hne bordering the periphery. Sculpture of coarse 
growth lines radiating from the periphery. At regular intervals there are 
larger rib-like projections, with four to six of the smaller ribs between. 
All the ribs extend into the spire cavity, which is deep. The sculpture is 
more conspicuous on the base of the shell. The umbilical (upper) side has 
the fine riblets more regularly spaced without the larger ones. This sculp- 
ture is most apparent on the large holotype specimen. There are likewise 
fine, impressed spiral lines. Aperture triangular, wider than high. Columella 
almost vertical. Lip thickened by callus, which includes the columellar and 
parietal walls. The right side of the aperture is acute and pinched. 
Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

1.1 1.6 Holotvpe 

1.0 1.5 Paratvpe 

0.9 0.9 Paratype 

Type Locality. Caloosahatchie River, Florida. 

Type Material. Pliocene fossils, collected by W. H. Dall, deposited in 
the United States National Museum, Accession no. 112556. Holotype 
figured on plate 140 as Fig. 22; paratypes as figs. 23, 24. 

Menetus dalli differs from alabamensis in the former's smaller and 
deeper spire depression and its heavier growth lines forming riblets. It was 
identified by Dall (after whom the new species is named) as exacuous. It 
was associated with dilntatus and alabamensis aims. 

Menetus dilatatus floridensis, New Variety 
Plate 123, figs. 20-22 

Shell small, of three whorls, slowly increasing in diameter. Color light 
horn. Body whorl forms a rounded obtuse angle as in dilatatus. Base flatly 
rounded. Spire depression wide, shallow, showing all of the whorls. Sculp- 
ture of fine growth lines crossed by fine spiral lines. Aperture rounded, 
not flaring. Outer lip thin. No callus on parietal wall. 

Shell Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

0.8 1.0 Holotype 

0.7 . S Paratype 

0.7 0.7 Paratype 

Type Locality. St. Johns River, Palatka, Florida. 

Type Material. Collected by W. H. Dall. Deposited in the United States 
National Museum, Accession no. 37585. Holotype shown on plate 123 as 
fig. 20; paratypes as figs. 21 and 22. 

Menetus dilatatus jioridensis differs from typical dilatatus in the fact 
that the new variety has a smaller aperture which is rounded, not flaring; 
has rounded body whorl, without trace of angulation; and has wider, shal- 
lower spire depression, showing all of the whorls. 

Menetus lahiatus. New Species 
Plate 121, figs. 9-11 

Whorls three, rounded. Spire flattened, apex sunken. Base rounded, umbili- 
cus broad and shallow, one-sixth the diameter of the shell. Whorls and 



0.9 


2.5 


2.1 


0.8 


2.3 


2.0 


O.S 


2.0 


1.6 



1.0 


2.6 


2.1 


0.9 


2.3 


2.0 


1.1 


3.1 


2.6 


1.2 


3.0 


2.3 



Descriptions of N'ew Species and New Varieties 233 

umbilicus rapidly increasing in diameter. Aperture ovately rounded, the 
lip with a heavy internal rim of callus which joins a distinct parietal callus, 
making the lip in some specimens continuous. Umbilicus varies in depth. 
Sculpture of fine growth lines, crossed by fine spiral lines, although the 
latter may be absent in some specimens. 

Shdl Greater Lesser Aperture Aperture 

Height Diameter Diameter Height Diameter 

0.5 0.5* Holotvpe 

0.5 0.5 Paratype 

0.6 0.5 Baker Coll., 2100 

0.8 O.S Baker Coll., 2100 

*A heavy callus redure.s the size (if the aperture. 

Type Locality. Terminal Island, Los Angeles County, California. 

Type Material. Three specimens, collected by Eastman, are in the 
United States National Museum, Accession no. 19002L Designated holotype 
and paratypes illustrated on plate 121 as figs. 11 and 9, 10, respectively. 

The type material was labelled as centervillensis. Taken in various 
southern California localities. Some large individuals of this species were 
collected from peat deposits by S. S. Berry, in Orange County, California. 
Two of these individuals, which have a heavy lip callus, are included as 
the third and fourth items in the above tabulation of shell characters 
(Baker Coll., no. 2100). 

Menetus labiatus differs from centervillensis in the shape of the um- 
bilicus and the aperture. 

Men&tus portlandensis, New Species 
Plate 121, figs. 12-18 

Shell less elevated than in centervillensis, the body whorl depressed, 
rounded on the periphery, not angled as in centervillensis. Spire flat, three 
and one-half whorls, sutures impressed. Color blackish to light horn, usu- 
ally in the same shell. Base flatter than in centervillensis; the umbilicus 
wider, about one-fourth of the diameter of the shell. Aperture transversely 
ovate, wider than in c enter vUlensis and not as nearly round. Slight callus 
on parietal wall. Sculpture of coarsely impressed spiral lines, distinct 
in all specimens examined. 



Shell 


Greater 


Lesser 


Aperture 


Aperture 




Height 


Diameter 


Diameter 


Height 


Diameter 




1.4 


4.0 


3.3 


1.1 


1.2 


Holotype 


1.3 


3.5 


3.0 


0.8 


1.0 


Paratype 


1.1 


3.3 


2.6 


0.8 


1.0 


Paratype 



Type Locality, Tanner Creek, Portland, Oregon. 

Type Material. A large collection of one hundred shells, collected by 
J. E. Benedict, is deposited in the United States National Museum, Acces- 
sion no. 184182. The holotype is shown on plate 121 as fig. 12; six para- 
types on the same plate as figs. 13 to 18. 

The chief distinguishing characteristics of Menetus portlandensis are 
that the umbilicus is wider and shallower and the sjiiral lines on the shell 
are heavier than in other species of the genus. 

This new species has also been taken in the vicinity of San Francisco, 
California, and at Astoria, Oregon. In the latter instance it was associated 
with specimens of coopcri. 



ILLUSTRATIONS OF THE ANATOMY 
AND OF SHELLS 



ANATOMICAL SYMBOLS USED ON THE PLATES 



A, anus 

AG, abdominal ganglion 

AL, albumen gland 

AO, aorta 

AP, pulmonary vein 

ARM, anterior retractor muscles 

AU, auricle 

B, bulbous termination of verge 
BG, buccal ganglion 

BP, buccal pouch 

BR, buccal retractor muscle 

BS, blind sac or caeciun 

BY. blood vessel 

BW, body wall of gland 

C, canal 

CF, carrefour 

CG, cerebral ganglion 
CL, cilia 

CM, columella muscle 

CMC, cut portion of mantle collar 

and columella muscle 
CR. crop 

D, diaphragm 

DA, duct from albumen gland 
DC, duct of gland 
DG, duct of preputium 
DV, duct entering vergic sac 

E, eye 

EPI, epiphallus-like swelling 

EUD, external opening of vas deferens 

F, foot 

FL, fiagellum 

FO, female opening 

FOV, diverticula of ovotestis 

FPR, diverticula of prostate 

G, accessory gland 
GA, gland appendage 

GF, folds in wall of gland cavity 

GL, penial gland 

GX, ganglion 

GR, growth lines 

GW, wall of preputial sac 

GZ, gizzard 

H, head 

HT, heart 

IC, cavity of gland connecting 

with gland duct 
IN, intestine or space for intestine 

on surface of albumen gland 
J. jaw 
K, kidney 
L, lung 

LJ, lateral jaw 
LV, liver 
M, mantle 
MC, mantle collar 
MO. male opening 
MX, muscle of neck 
MP, muscular pads or pillars in 

preputium ( pilasters) 
MR, muscular ridge or diaphragm 
MS, suspensarv muscles of verge 
MT, mouth 
X^, nerve 



NA, section through neck 

NG, nidamental gland 

NS, new shell forming 

OC, outer cup of gland 

OD, oviduct 

OE, oesophagus 

OLV, opening of liver duct into stomach 

OT, ovotestis 

P, jiseudobranch 

PA, vergic appendage 

PC, pericardium 

PD, duct of prostate 

PF, prostate diverticula 

PG, pedal ganglia 

PL, pilasters 

PP, papilla in preputium 

PR, preputium 

PRM, posterior retractor muscle 

PRS, prostate 

PS, pneumostome 

PY, pyloris 

R, rectum 

RA, renal vein 

RD, ridge 

RK, ridge on kidney 

RL, radula 

RM, retractor muscle 

S, spermatheca 

SB, sarcobelum 

SC, sperm canal 

SD, spermathecal duct 

SG, salivary gland 

SCO, opening of sperm canal 

SJ, superior jaw 

SH, shell 

SK, saccular part of kidney 

SM, supporting muscle 

SO, ovisperm duct 

SP, spermatophore 

SPD, sperm duct 

ST, stylet 

STM, stomach 

SV, seminal vesicle 

T, tentacle 

TK, tubular part of kidney 

U, uterus 

UO, external opening of ureter 

UR, ureter 

V. verge 

VC, vergic sac 

VD, vas deferens 

VDV, vas deferens in vergic sac 

VF, folds in vergic sac 

VG, vagina 

VGL, visceral ganglion 

VL, velum 

VM, muscle to vergic sac 

VX, vein 

VO, opening between vergic sac 

and preputium 
VP, vergic papilla 
VS, vergic sac 
VT, ventricle 
X. canal in penial gland 



238 The Molluscan Family Plauorbidae 



PLATE 1 

Planorbis planorbis (Linn.) 
From a pond 25 miles southeast of Warsaw, Poland; from A. Jankowski. 

1. Entire genital system spread out. The dark spaces are folds in the anatomical 

preparation. 

2. Penial complex with muscles. 

3. Head and foot showing form of pseudobranch. 

4. Vertical section through penial complex to show small size of verge. 

5. Section through verge and vas deferens. 

6. Junction of oviduct and vas deferens to form ovisperm duct and connection with 

albumen gland and carrefour. 

7. Section through prostate, oviduct, and vas deferens showing a prostate canal sepa- 

rated from the vas deferens. 

8. Section through ovotestis. 

9. Section through o\'otestis showing di\'erticula embedded in the liver cells. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 239 




PLATE 1 



240 The Molluscan Family Planorbidae 



PLATE 2 

Segmentina and Hippeutis 

1-6. Segmentina nitida (Miiller). From swamps on a meadow near Warsaw, Poland; 
from A. Jankowski. 

1. Cross section of pilaster to which appendage is attached. 

2. Vertical section of preputium showing position of gland-like appendage. 

3. Upper view of cup of gland or appendage. 

4. Vertical section of gland or appendage. 

5. End of verge showing position of vergic appendage. 

6. End of verge showing vergic appendage and outlet of sperm canal. 

7-15. Hippeutis complanatus (Linn.). From pool in meadow in Jabtonna, 16 km. north 
of Warsaw, Poland; collected by A. Jankowski. 

7. Two diverticula of ovotestis. 

8. Cross section of prostate showing two canals, one for prostate (PD) and one 

for sperm duct (SPD). 

9. Gland or appendage in preputium. 

10. Outline of albumen gland (from above). 

11. Upper part of vergic sac showing two flagella and the vas deferens. 

12. Vertical section of penial complex showing relationship of verge, gland, or 

appendage, and flagella. 

13. Head of animal showing form of pseudobranch and pneumostome. 

14. Penial complex from the outside. 

15. General dissection of genitalia omitting the penial complex. 

Line near figure indicates 1 mm. in length. Line at left of fig. 12 also indi- 
cates .size of figs. 3, 4, 5, 8, and 9. Figures 6 and 11 are greatly 
enlarged. Figure 14 has same magnification as fig. 15. 



Illustrations of the Anatomy and of Shells 241 



VD FL 




PRS 



242 The Molluscan Family Planorhidae 



PLATE 3 

Segmentina and Bathyo))iphalus 

1-4. Segmentina nitida (Miiller). From meadow near Warsaw, Poland; from A. Jan- 
kowski. 

1. External view of penial complex. 

2. Hermaphrodite complex. 

3. Cross section of prostate and ducts of prostate and vas deferens. 

4. Head showing position and form of pseudobranch. 

5-10. Bathyomphalus contortus (Linn.). From Drewnica, a turfy ground 4 km. north- 
east of Warsaw, Poland; collected by A. Jankowski. 

5. Head showing position and form of pseudobranch. 

6. Pseudobranch showing position of rectum. 

7. Cross section of ovotestis. 

8. Cross section of prostate showing prostate duct sei)arate from sperm duct. 

9. Penial complex from the outside. 

10. Hermaphrodite complex dissected and spread out. 

Line near figure indicates 1 mm. in length. Line at left of fig. 7 also repre- 
sents size of figs. 3 and 8. Figure 9 is same magnification as fig. 10. 



Illustrations of the Anatomy and of Shells 243 




PLATE 3 



244 The Molluscan Family Plauorbidae 



PLATE 4 

Pingiella peipinensis (Ping and Yen). New genus 
Peiping, China; from Fan Memorial Institute, Peiping, China. 

1. Albumen gland showing position of stomach. 

2. Portion of penial gland showing position of ducts. 

3. Terminal end of penial gland, imder side. 

4. Terminal end of penial gland, view from side showing internal canal. 

5. Penial complex showing long duct of penial gland and long and peculiarly formed 

appendages. 

6. Preputium cut open to show penial gland. 

7. Preputium cut open to show penial gland and relationship of long duct. 

8. Verge in vergic sac. 

9. General dissection of genitalia, the organs separated and extended. 

Line near figure indicates 1 mm. in length. Figures 3 and 4 
are greatly enlarged. 



lUustratioiis of the Anatomy and of Shells 245 




246 The Molluscan Family Planorbidae 



PLATE 5 

Pingiella and Polypylis 

1,5. Pingiella peipinensis (Ping and Yen), new genus. Peiping, China. 

1. Region of the pseudobranch. 

5. Spermatheca of different shape. 

2-4,6,7. Polypylis hemisphaerula (Benson). Peiping, China; from Fan Memorial 
Institute. 

2. Outline of albumen gland. 

3. Region of the pseudobranch. 

4. Section through prostate and ducts. 

6. Distal end of verge showing outlet of canal at the side. 

7. Entire genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length. Figure 6 is greatly enlarged. 



Illustrations of the Anatomy and of Shells 247 




PLATE 5 



248 The Molluscan Family Planorbidae 



PLATE 6 

Anisus vortex and Anisus spirorbis 

1-4,6. Anisufi vortex (Linn.). From stream in meadow in Jabtonna. 18 km. north- 
east of Warsaw, Poland; collected by A. Jankowski. 

1. Penial complex showing long and narrow vergic sac. 

2. Stylet, drj' and somewhat crushed. 

3. Section through prostate and sperm canal showing two ducts. 

4. Section through upper portion or preputium and vergic sac, showing papiUa in 

preputium, stylet and outlet of sperm canal at the side of the verge. 

6. Pseudobranch showing relationship to rectum. 

5,7-13. Aiiisus spirorbis (Linn.). From a trench in Struga, 12 km. northeast of War- 
saw, Poland; collected by A. Jankowski. 

5. St5det at end of verge with outlet of sperm canal at side of verge. 

7. Two diverticula of ovotestis. 

8. Cross section through prostate and o\ iduct. 

9. Albumen gland, upper part. 

10. Penial complex in vertical section showing stylet, muscular i)apilla, and jiilasters. 

11. Foot, pseudobranch, and jmeumostome. 

12. Entire genitalia dissected and separated. 

13. Penial complex of specimen with vergic sac shortened and club-shaped. 

Line near figure indicates 1 mm. in length. Figures 2 and 5 
are greatly enlarged. 



Illustrations of the Anatomy aiid of Shells 249 




PLATE 6 



250 The Molluscan Family Planorbidae 



PLATE 7 

Anisus leucostomus and Ainsus septemgyratus 

1-5. Anisus leucostomus (Millet). From small pond in Bielany Park, Warsaw. Poland; 
collected by A. Jankowski. 

1. Foot, pseudobranch, and pneumostome. 

2. Genitalia dissected and the organs separated. Figure under seminal vesicle 

shows this organ stretched out. 

3. Muscular ring or diaphragm in upper part of preputiimi showing papilla with 

stylet protruding. 

4. End of oviduct and vas deferens showing where ovisperm duct joins the ovi- 

duct and vas deferens. 

5. Stylet. 

6. Anisus septemgyratus (Ziegler). From turfy meadow in Drewnica, 4 km. northwest 
of Warsaw, Poland; collected by A. Jankowski. 

6. Outline of genitalia exclusive of the penial complex. 

Line near figure indicates 1 mm. in length. Line at left of 
fig. 5 is only for .size of figs. 3 and 4. 



Illustrations of the Anatomy and of Shells 



251 




PLATE 7 



252 The Molluscan Family Planorbidae 



PLATE 8 

Intha and Polypylis 

1-8,11. Intha capitis Annandale. From Inle Lake, South Shan State, Burma, India; 
collected by Dr. N. Annandale. 

1. Outline of albumen gland. 

2. Pseudobranch and rectum. 

3. Head of animal showing tentacles and eyes. 

4. Distal end of verge. 

5. A spermatophore. 

6. Penial complex, dorsal view. 

7. Cross section of penial gland. 

8. Vertical section of penial complex showing verge, gland, and duct. 

11. ^'entral view of entire genitalia, showing the large size of the fiagella. 

9,10. Polypylis hemisphacnda (Benson). Peiping, China; from Fan Memorial In- 
stitute. 

9. Section of penial complex cut open to show verge, diaphragm and pilasters. 

10. Penial complex, ventral view. Small figure at right shows insertion of vas 
deferens at junction of vergic sac and flagellum. Dorsal view. 

Line near figure indicates 1 mm. in length. Figures 1, 5, 6. and 7 have 
same magnification as fig. 11. Figure 4 is greatly enlarged. 



Illustrations of the Anatomy and of Shells 253 




254 The Molluscan Family Planorbidae 



PLATE 9 

Drepanotrema and Australorbis 

1-3. Drepanotrema anatinitm (Orbigny). From Viejo, Puerto Rico; from Dr. W. A. 
Hoffman. 

1. Penial complex showing form of flagellum. 

2. Genitalia dissected and organs separated. Note the small number of ijrostate 

diverticula. 

3. Head and foot showing form of pseudobranch. 

4-10. Australorbis globratus (Say). From Lares, Puerto Rico; from Dr. W. A. Hoff- 
man. 

4. Cross section of portion of ovotestis to show multiple branched diverticula. 

5. Distal end of verge showing opening at center. 

6. One diverticulum of prostate showing multiple branching at end. 

7. Pseudobranch and pneumostome. 

8. Outline of albumen gland showing depression occupied by intestine. 

9. Section of penial complex showing long and narrow verge and vergic sac. 

10. Entire genitalia dissected and organs separated. Note branched form of pros- 
tate diverticula and multiple nature of ovotestis diverticula. 

Line near figure indicates 1 mm. in length. Line near 
left of fig. 1 is also for fig. 3. 



Illustrations of the Atiatomy cuid of Shells 255 




PLATE 9 



256 The Molluscan Family Planorbidae 



PLATE 10 

Drepanotrema hoffmani F. C. Baker 
From Isabela, Puerto Rico; collected by Dr. W. A. Hoffman. 

1. Animal removed from shell showing pigmentation of mantle, shape of head and 

tentacles, and position of stomach (STM) in body. 

2. Genitalia dissected and organs separated. 

3. Fore part of body showing head, pseudobranch, etc. 

4. Albumen gland showing attachment of ducts. 

5. Penial complex showing attachment of short flagellum, vas deferens, etc. 

6. Section of penial complex showing verge, pilasters, vas deferens, flagellum, etc. 

7. Upper part of penial complex showing relationship of flagellum, vas deferens, vergic 

sac, retractor muscle, etc. 

8. Penial complex of another specimen. 

9. Distal end of verge showing central outlet of sperm canal. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 257 




PLATE 10 



258 The Molluscan Family Planorbidae 



PLATE 11 

Drepanotrema lucidum (Pfciffer) 
From Havana, Cuba; collected by Dr. C. G. Aguayo. 

1. Head and foot with prepiitium and verge extended from male genital opening. The 

pseudobranch and rectum are also shown. 

2. Head and foot with only preputinm extended from male genital opening. 

3. Genital system dissected and organs separated. 

4. Penial complex showing flagellum, vas deferens, etc. 

5. Penial complex with very long flagellum. 

6. Diagram of penial complex showing preputium and \crge extended from male 

genital opening. 

7. Relationship of vas deferens, flagellum, retractor muscle in body of animal in 

specimen with preputium and verge extended from male opening. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 259 




PLATE 11 



260 The Molhiscan Family Plauorhidae 



PLATE 12 

Tropicorbis havanensis (Pfeiffer) 
From Xew Orleans, La.; collected by Dr. E. Carroll Faust. 

1. Penial complex in section to show verge and pilasters in vergic sac. 

2. Muscular ring or ridge between vergic sac and preputium (diaphragm). 

3. Distal end of verge showing central opening of sperm canal. 

4. Body of snail showing pseudobranch, pneumostome, rectum, and frilled ridge or 

crest over rectum. 

5. Body of snail showing pigmentation of mantle. 

6. Albumen gland from above. 

7. Portion of genitalia at junction of oviduct and sperm duct with ovisperm duct. 

Also entrance of albumen duct into carrefour and thence to oviduct. From below. 

8. Same as fig. 7, from above. 

9. Single diverticulum of prostate showing canal distinct from that of sperm duct. 

10. Penial complex showing enlargement of preputial sac. 

11. Genitalia dissected and the organs separated, showing relationship of all organs. 

Line near figure indicates 1 mm. in length. Lme at left of fig. 1 is also 
for figs. 7, 8, and 9. Line at left of fig. 11 is also size for fig. 6. 



Illustrations of the Anatomy and of Shells 



261 




PRS 



PLATE 12 



262 The Molluscan Family Planorhidae 



PLATE 13 

Tropicorbis 

1-3. Tropicorbis obstructus (Morelet). From New Orleans, La.; collected by Dr. E. C. 
Faust. 

1. Genitalia dissected and organs separated. 

2. Cross section of ovotestis in non-gravid stage. 

3. Cross section of ovotestis in gravid stage with ova in diverticula. Line at right 

indicates 0.5 mm. in length. 

4-10. Tropicorbis riisci (Dunker). From Lares, Puerto Rico; from Dr. W. A. Hoffman. 
4,5. Cross sections of prostate diverticula showing bending at end. Also presence 
of prostate duct distinct from sperm duct. 

6. Penial complex, external view\ 

7. Albumen gland from below showing duct (DA). 

8. Vas deferens showing branching to form sperm duct and prostate duct (greatly 

enlarged) . 

9. Portion of genitalia dissected and organs separated. Organs as in fig. 1. 

10. Head of animal showing pseudobranch and imeumostome as well as ridge over 
rectum. 

Line near figure indicates 1 mm. in length. Line at left of 
figs. 4 and 5 is for both figures. 



Illustrations of the Anatomy and of Shells 263 




PRS 



PLATE 13 



264 The Molluscan Family Plauorbidae 



PLATE 14 

Gyraulus albus (Miiller) 
From pond in Krolikania, a suburb of Warsaw, Poland; from A. Jankowski. 

1. Penial complex sectioned to show verge, stylet, etc. 

2. Penial complex, external view. 

3. Fore part of animal showing pseudobranch and pneumostome. 

4. Fore part of animal showing pseudobranch, pneumostome, and venation of some 

of these organs. 

5. Albumen gland from below. 

6. Portion of genitalia showing attachments of albumen gland duct, oviduct, sperm 

duct, and general relationship of these and other organs. 

7. Genitalia dissected and organs separated. 

8. Stylet at end of verge with sperm canal outlet at side of verge. 

9. Section of prostate showing distinct canals for prostate and sperm duct. Three 

diverticula are shown. 

10. Section through ovotestis near front end. 

11. Distal end of ovotestis showing grouping of diverticula. 

Line near figure indicates 1 mm. in length. Line at lower right corner 

of plate is for figs. 5, 6, 7. 9, 10, and 11. Figure 8 line is 

one-sixth of 1 mm. in length. 



Illustrations of the Anatomy and of Shells 265 




PLATE 14 



266 The Molluscan Family Planorbidae 



PLATE 15 

Gyraulus 

1-7. Gyraulus hirsutus (Gould). From Bass Creek, Lake Nipissing, Ontario, Canada; 
received from A. LaRocqiie. 

1. Genitalia dissected and organs separated. A portion of the intestine is shown 

beneath the albumen gland. 

2. Penial complex, external view. 

3. Fore end of body showing pseudobranch, pneumostome, rectum, etc. 

4. Distal end of genitalia showing connection of various ducts. From right side. 

5. Same as fig. 4, from left side. 

6. A single diverticuhun of the prostate with duct separate from the sperm duct. 

7. Two diverticula of the ovotestis. 

8-10. Gyraulus vcrmicularis (Gould). From Stone Lake, Golden Gate Park, San 
Francisco, California; from Dr. G. D. Hanna. 

8. Fore end of body showing pseudobranch. 

9. Distal end of genitalia showing relationship of ducts. 
10. Genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length. Line in upper left 
corner of plate is for figs. 4, 5, 6, and 7. 



Illustrations of the Anatomy and of Shells 267 




PLATE 15 



268 The Molluscan Family Planorhidae 



PLATE 16 

Gyraulus deflectus obliquus (DeKay) 
From Taylor Lake, Masham, Quebec, Canada; collected by A. LaRocque. 

L Penial complex in vertical section. 

2. Penial complex of specimen with bulbous termination of vergic sac. 

3. External view of penial complex showing relationship of parts. Also male opening 

behind tentacle. 

4. Genitalia dissected and organs separated. 

5. Section through portion of penial complex at junction of vergic sac and preputial 

sac to show thickened portion with papilla. 

6. Stylet. Distal end of verge shows sperm canal outlet at side. 

7. Terminal diverticula of ovotestis, showing de\-eloping ova. 

8. Terminal diverticula of ovotestis from left side. 

9. Section through diverticula of ovotestis. 

10. Distal end of genitalia showing position of sperm duct, oviduct, albumen duct, etc. 

11. Section of prostate near middle. 

12. Section of prostate six diverticula from front end. 

13. Body and foot of animal showing pseudobranch, etc. 

14. Pseudobranch showing network of blood vessels. 

15. Another form of pseudobranch. 

Line near figure indicates 1 mm. in length. Line at middle left of i)late 
indicates size of figs. 5, 6. 7, 8, 9, 11, and 12. 



IllustrdtioDS of the Anatomy and of Shells 269 




11 12 



PLATE 16 



270 The MoUuscan Family Planorbidae 



PLATE 17 

Gyraulus 

1-5. Gyraulus circumstriatus (Tryon). From Wainwright Park, near Mott Lake, 
Alberta, Canada; collected by Dr. Swales. 

1. Genitalia dissected and organs separated. Outline. Penial complex in natural 

position. 

2. Distal end of genitalia showing duct connections. From left side. 

3. Pseudobranch and pneiunostome. 

4. Animal removed from shell showing position of several organs. 

5. Two diverticula of ovotestis in gravid condition. 

6-12. Gyraulus parvus (Say). From Winnebago Lake, near Oshkosh, Wisconsin; col- 
lected by F. C. Baker. 

6. Genitalia dissected and organs separated. 

7. Distal end of genitalia, from left side. 

8. Portion of fore end of animal showing pseudobranch, etc. 

9. Albumen gland showing attachment of oviduct. 

10. Three di^'erticula of prostate with prostate duct below and sperm duct at the 

side. 

11. Two diverticula of ovotestis. 

12. Penial complex opened to show verge, stylet, papilla, etc. 

Line near figure indicates 1 mm. in length. Figures 5, 10, and 
11 have same magnification as fig. 12. 



Illustratious of the Anatomy and of Shells 271 




272 The Molluscan Family Planorbidae 



PLATE 18 

Gyraulus and Arniiger 

1-5. Gyrauhis similaris (F. C. Baker). From Smartweed Lake, near Tolland, Colorado; 
collected by Dr. Frank Smith. 

1. Genitalia dissected and organs separated. 

2. Distal end of genitalia showing arrangement of durt.'<. 

3. Penial complex in section showing verge, stylet, and preputium. 

4. Stjdet. Outlet of sperm canal is shown at side of verge. 

5. Head and foot of animal showing pseiidobranch. 

6-11. Armiger crista (Linn.). From pond in Krolikarnia, a suburb of Warsaw, Poland; 
collected by A. Jankowski. 

6. Head showing form of pseudobranch. 

7. Genitalia dissected and organs separated. 

8. Albumen gland from side. 

9. Penial complex in .section showing verge without stylet. 

10. End of verge showing absence of stylet and jjresence of a fleshy papilla. 

Sperm canal with outlet in center of verge. 

11. End of verge from side showing relationship of jiapilla and canal. 

Line near figure usually indicates 1 mm. in length. Line at left of fig. 4 

measures one-fifth of 1 mm. Line in center of fig. 7 is also for 

fig. 8. Same line equals 0.5 mm. for fig. 9. 

Figures 10 and 11 are much enlarged. 



Illustrations of the Anatomy and of Shells 273 




274 The Molluscan Family Planorbidae 



PLATE 19 

Gyi'aulus 

1-3. Gyraidus co7ivexiusculus (Hutton). From Calcutta, India; from Dr. B. Prashad. 

1. Cross section of one diverticulum of prostate showing separate canals for 

prostate duct and sperm duct. 

2. Genitalia dissected and organs separated. 

3. Pseudobranch and pneumostome. 

4-9. Gyraulus latestomus F. C. Baker. From Cedar Lake, Algonquin Park, Ontario, 
Canada; collected by A. LaRocque. 

4. Distal end of genitalia from left side. 

5. Albumen gland from below, showing loop of intestine. 

6. Penial complex. 

7. Cross section of one diverticulum of prostate. 

8. Anterior end of body showing pseudobranch and ])neumostome. 

9. Genitalia dissected and the organs separated. 

Line near figure indicates 1 mm. in length. Figures 1 and 7 
are greatly enlarged. 



Illustratioihs of the Anatomij and of Shells 275 




PLATE 19 



276 The MoUuscan Family Planorhidae 



PLATE 20 

Planorbarius corneus (Linn.)- 

From branch of Wista River at Morysinek, 5 km. .south of Warsaw, Pohuid; 
collected by A. Jankovvski. 

1. Penial gland and appendages in extended position. 

2. Section through appendage at C in fig. 1. 

3. One diverticulum of ovotestis with ripe ovum (greatly enlarged). 

4. Cro.ss section through prostate, uterus, and nidamental gland. 

5. Cross section of ovotestis in gravid specimen. 

6. Vergic sac opened to show verge and canal in gland. 

7. Retractor muscles in tyjjical specimen. 

8. End of verge showing i)enial appendage. 

9. Albumen gland. 

10. Portion of head .showing jiseudobranch, pneumcstome, and rectum with ridge. 

11. Penial complex opened to show position of jienial gland, verge, pilasters, etc. 

Penial appendage is retracted. 

12. Penial complex from outside showing muscles. 

13. Genitalia dissected and organs separated, showing particularly the form of jirostate 

and its junction with the vas deferens and sperm duct. 

Line near figure indicates 1 nmi. in length. Line at right of fig. 1 is also for 
fig. 2. Line at left of fig. 6 represents 0.5 mm. in length. 



lUustratioihs of the Auatouiy and of Shells 

NG 



277 




278 The Molluscan Family Planorbidae 



PLATE 21 

Indoplanorbis exustus (Deshayes) 

From Hsipaw, North Shan State, Burma, India; collected by Dr. B. N. 
Chopra and Dr. H. S. Rao; contributed by Dr. B. Prashad. 

1. Pcnial complex in natural position. 

2. Fore part of animal showing pseudobranch and pneumostome, with preputium 

protruded from male opening and lying on the neck of the animal. 

3. Genitalia dissected and organs separated. 

4. Pleated pseudobranch and pneumostome. 

5. Under side of preputium everted through male opening in the neck of the animal. 

6. Pseudobranch from side showing branched or pleated condition. 

7. Cross section of ovotestis showing se\'eral gra\id diverticula. 

8. Cross section of prostate. 

9. Two diverticula of prostate. 

10. Portion of prostate showing relationship of vas deferens, sperm duct, and diver- 
ticula of gland. 

Line near figure indicates 1 mm. in length. Figures 9 and 10 are greatly 

magnified. Figures 1, 2, 3, and 10 were published in 

Jour. Mori)h., LV, plates 1 and 2. 



Illustrations of the Anatomy and of Shells 279 




PLATE 21 



280 The Molluscan Family Plauorbidae 



PLATE 22 

Indoplanorbis and Helisoma 

5-9. Indoplanorbis exustus (Deshayes). Continued from plate 21. 

5. Retractor muscle of verge showing branching to vergic sac. Also nerve 

connection. 

6. Cross section of preputium in extended condition as .-^hown in fig. 7. 

7. Penial complex of specimen in breeding condition with preputium extended 

from male opening in neck. Compare with fig. 1 on plate 21. 

8. Section of vergic sac through bulbous termination of verge. 

9. Section of vergic sac through verge. 

Line near figure indicates 1 mm. in length. Figure 5 is enlarged. Figure 6 

has same magnification as fig. 7. These figures 

were published in Jour. Morph. 



1. Helisoma anccps latchfordi (Pilsbry). 

1. Verge. Also enlarged portion of vas deferens (epiphallus). 

2-4,11. Helisoma anccps pcrcarinatiDii (Walker). 

2-4. A'ariation in form of muscles and in position of verge in preputium. Greatly 
enlarged. 

11. Penial gland with cup turned back to show folds in inner cup. 

10, 12. Helisoma anccps (Menke). 

10. End of verge .showing papilla and sperm canal outlet. 

12. Prostate showing attachment of prostate duct to sperm duct. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 281 




282 The Molluscan Faintly Planorbidae 



PLATE 23 

Helisoma anceps (Menke) 

1-4,7-11. Helisoma anceps (Menke). From Gillespies Pond, Collinsville, Connecticut; 
collected bj^ F. C. Baker and Leslie Brewer. 

1. Cross section of penial gland showing cup, folds, and duct. 

2. Section of penial complex to show position of gland in preputium. 

3. Exterior view of penial complex showing short duct on outside of preputium. 

4. Region of the neck showing pseudobranch, pneumostome, and rectum. 

7. Albumen gland from below. 

8. Penial complex of specimen in which gland in preputium has been pushed 

upward. 

9. Cross section of prostate showing multiple form of diverticula. 

10. Cross section of ovotestis. 

11. Genitalia dissected and organs separated. 

5,6. Helisoma anceps latchfordi (Pilsbry). From Meach Lake, Quebec, Canada; col- 
lected by A. LaRocque. 

5. Diaphragm in preputial sac view from below. 

6. Section through diaphragm showing entrance of gland duct into vergic sac 

cavity just above diaphragm. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 283 




~PRS 



PLATE 23 



284 The Molluscan Family Planorbidae 



PLATE 24 

Helisoma trivolvis (Say) 

Collected from Oneida Lake, New York, by F. C. Baker, 
except where otherwise stated. 

L Penial complex. Specimen with portion of preputium containing gland pushed 
upward. Pool near Green Lake, Wisconsin. 

2. Penial complex in vertical section. Specimen with preputium pushed upward. 

Illinois River, near Peoria, Illinois. 

3. Penial complex. Young specimen with 3Vi> whorls. Devils Lake, Wisconsin. 

4. Section through penial gland showing folds in cup. 

5. Penial complex in immature specimen. Pond near Sturgeon Bay, Wisconsin. 

6. Side view of albumen gland. 

7. Albumen gland from below. 

8. Section through penial gland in specimen in normal, non-breeding condition. 

9. Section through ovotestis near anterior end. 

10. Section through penial complex in region of diaphragm. 

IL External view of penial complex showing duct uncoiled and stretched out, indi- 
cating great length. 

12. Region of neck showing pseudobranch, pncumostome, rectum, etc. 

13. Section through prostate and uterus near middle of gland. 

14. Penial gland somewhat contracted at cup end. 

15. Genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 285 




PLATE 24 



286 The Molluscan Family Planorbidae 



PLATE 25 

Helisoma pilsbryi (F. C. Baker) 

1-7. Helisoma pilsbryi (F. C. Baker). From Chetek Lake, Barron County, Wisconsin; 
collected by F. C. Baker. 

1. Penial complex with vergic sac drawn to side of preputium. 

2. Cross section of penial gland. 

3. Pseudobranch and pneumostome. 

4. Outline of genitalia with organs separated. 

5. Penial complex from outside, in normal position. 

6. Penial comjilex of specimen with preimtium pushed upward. 

7. Penial complex showing great length of penial gland duct. 

8-13. Helisoma pilsbryi injracarinatum F. C. Baker. Unless otherwise stated specimens 
are from Basswood River Rapids, Ontario, Canada; collected by A. R. Cahn. 

8. Penial complex of specimen with large preputium. From Rideau River Rapids, 

Ottawa, Canada; collected by A. LaRocque. 

9. Penial complex with preputium pushed upward, showing length of penial 

gland duct. 

10. Penial complex of immature specimen. From Bamiji Lake, Ontario, Canada; 

collected by Dr. A. R. Cahn. 

11. Pseudobranch and adjacent organs. 

12. Section through prostate and uterus. 

13. Outline of genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length 



Illustrations oj the Anatomy and of Shells 287 




PLATE 25 



288 The Molluscan Family Planorhidae 



PLATE 26 

Helisoma 

1-5. Helisoma horni (Tiyon). From Paul Lake, British Columbia; collected by Prof. 
D. S. Rawson. 

1. Penial complex in breeding condition, the preputium pushed upward. 

2. Outline of penial gland. 

3. Outline of genitalia dissected and organs separated. 

4. Cross section through oviduct, sperm duct, and nidamental gland. 

5. Cross section through prostate and o\iduct, near middle of gland. 

6-13. Helisoma iruncatum (Miles). From Winnebago Lake, near Oshkosh, Wisconsin; 
collected by F. C. Baker. 

6. Penial complex with penial gland duct in normal position coiled on surface of 

preputium. 

7. Penial complex with penial gland duct pulled out to show great length. 

8. Cross section of ovotestis near anterior end. 

9. Cross section of penial gland. 

10. Cross section of prostate and oviduct near anterior end. 

11. Head showing position of pseudobranch, pneumostome, and rectum. 

12. Penial complex with penial gland duct spread out. Preputium is partly pushed 

upward. 

13. Genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 289 




PLATE 26 



290 The Molluscan Family Planorbidae 



PLATE 27 

Helisoma campamdatum (Say) 
From Oneida Lake, New York, near Brewerton; collected by F. C. Baker. 

1. Section through penial gland. 

2. Albumen gland from below. 

3. Section through diaphragm showing relationship of penial gland duct to vergic 

sac. 

4. Section through ovotestis near anterior end. 

5-7. Penial complex of Helisoma campayiulatum sniithi (F. C. Baker), from 
Douglas Lake, Michigan, showing variation in form, especially the preputium. 

-14. Helisoma campaiudatinn canadense F. C. Baker. From Sturgeon Lake, Ontario, 
Canada; collected by Dr. A. R. Cahn. 

8. Penial complex. 

9. Penial complex showing penial gland duct coiled between preputium and 

vergic sac. Also variation in muscles. 

10. Section of penial complex showing relationship of penial gland to verge. 

11. Penial complex with penial gland duct uncoiled to show length. 

12. Section through prostate near middle of gland. 

13. Pseudobranch, pneumostome, and rectum. 

14. Genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length 



Illustrations oj the Anatomy and oj Shells 



291 




PLATE 27 



292 The MoUuscan Family Plauorhidae 



PLATE 28 

Helisoma 

1-5. Helisoma oregoncnse (Tryon). From Tooele Co., Utah; collected by J. Hen- 
derson. 

1. Penial complex showing long penial gland duct. 

2. Genitalia dissected and organs separated. 

3. Cross section of prostate near middle of gland. 

4. Penial gland viewed from above. 

5. Section through penial gland. 

6-14. Helisoma scalare (Jaj'). From Lake Butler, Florida; received from Dr. E. A. 
Andrews. 

6. Entrance of penial gland duct into vergic sac. 

7. Section through penial gland. 

8. Pseudobranch and pneumostome. 

9. Penial complex with preputium pushed upward. 

10. Penial complex in normal position, the penial gland duct extended. 

11. Penial complex in section to show relationship of organs. 

12. Section through prostate near middle. 

13. Section through ovotestis near anterior end. 

14. Genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length 



Illustratio))s of the Anatomy and of Shells 293 




PLATE 28 



294 The MoUuscan Family Planorbidae 



PLATE 29 

Helisoma 

1-6. Helisoma trivolvis pseudotrivoivis (F. C. Baker) ^ lentum Say. From St. Joseph, 
Champaign Co., Illinois; collected by F. C. Baker. 

1. Penial complex with penial gland duct spread out to show length. 

2. Penial complex in section showing penial gland m natural position in pre- 

putium. 

3. Penial complex with penial gland duct coiled on preputium. 

4. Penial gland in section. 

5. Penial complex in section showing preputium pushed upward and penial gland 

duct vmcoiled. From Illinois River, Peoria, Illinois. 

6. Neck of animal showing penial gland everted. From Reelfoot Lake, Tennessee. 

7-13. Helisoma trivolvis lentum (Say). From Xew Orleans, Louisiana; collected by 
E. C. Faust. 

7. Penial complex with penial gland everted. 

8. Penial complex with penial gland duct uncoiled. 

9. Verge fully extended with sections in two places as indicated. 

10. End of verge showing exit of sperm canal with small, lip-like processes sur- 

rounding the opening. 

11. Head and neck of animal showing penial gland and verge everted. 

12. Penial complex with penial gland and verge everted. 

13. Verge in fig. 12 removed from penial complex. 

14-16. Helisoma trivolvis macrostomum (Whiteaves). 

14. Penial complex. From Bayfield, Wisconsin; collected by F. C. Baker. 

15. Penial complex with preputium pushed upward. Same locality as fig. 14. 

16. Penial complex with penial gland duct uncoiled. From Lake Gauvreau, 

Canada; collected by A. LaRocque. 

17,18. Helisoma trivolvis fallax (Haldeman). From Cambridge, Massachusetts; col- 
lected by W. J. Clench. 

17. Penial complex showing large size of preputium. 

18. Exterior view of penial gland. 

19-22. Helisoma chautauquense F. C. Baker. From Chautauqua Lake, New York; 
collected by F. C. Baker. 

19. Penial complex of immature specimen. 

20. Exterior view of penial gland. 

21. Verge much retracted. 

22. Penial complex of adult .specimen in normal condition. 

Line near figure indicates 1 mm. in length. In fig. 10 line equals 0.5 mm. 



Illustrations of the Anatomy and of Shells 295 




296 The Molluscan Family Planorbidae 



PLATE 30 

Helisonia 

1-9. Helisoma plcxatum (Ingersoll). Collected by J. Henderson. 

1. Penial complex with penial gland duct uncoiled. From Columbine Lake, 

Colorado. 

2. Penial complex with vergic sac cut open to show form of verge. 

3. Penial comiilex in section to show form of gland. From Columbine Lake, 

Colorado. 

4. Genitalia dissected and organs separated. From Smartweed Lake, Colorado. 

5. Cross section of penial gland. From Lower Los Lagos, near Smartweed Lake. 
6-8. Section of vergic sac showing form of \erge in different individuals. From 

Teton River, north of Rexburg, Idaho. 
9. Form of verge in a specimen from Smartweed Lake, Colorado. 

10-19. Helisoma subcrcnalum (P. P. Carpenter). From one mile west of Devon, 
Montana; collected by J. Henderson. 

10. Penial complex showing short penial gland duct in immature specimen. 

11. Section of penial gland. 

12. Cross section of prostate about midway of its length. 

13. Section through penial complex showing verge and penial gland. 

14. Albumen gland from below. 

15. Genitalia dissected and organs separated. 

16. Head showing pseudobranch, pneumostome, and rectum. 

17. Penial complex with penial gland duct uncoiled. 

18. Penial complex in section showing form of penial gland and verge. 

19. Penial complex with vergic sac cut open to show verge. Figures 17-19 are 

from specimens collected at Cottonwood Pass, near Gypsum, Colorado. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 297 




298 The Molluscan Family Planorbidae 



PLATE 31 
Helisoyna 

1-7. Helisoma corpulent lun (Say). From Knife Lake, Minne.?ota and Lake La Croix, 
Ontario; collected by Dr. A. R. Cahn. 

1. Cross section of ovotestis. From Knife Lake. 

2. Cross section of prostate and uterus at X in fi^. 3. From Knife Lake. 

3. Genitalia dissected and organs separated. From Knife Lake. 

4. Penial complex with preputium pushed upward and penial gland duct imcoiled. 

5. Penial complex and penial gland duct in natural position. From Knife Lake. 

6. Penial complex of immature specimen, shell 12 nun. in diameter. From Lake 

La Croix. 

7. Penial complex of specimen with shell 14 mm. in diameter. From Lake La 

Croix. 

8-13. Helisoma corpulentinn multicostotum F. C. Baker. From Kahnipiminanicock 
Lake, Ontario, Canada; collected by Dr. A. R. Cahn. 

8. Cross section of penial gland. Duct not shown. 

9. Penial complex of immature specimen, shell 5.5 mm. in diameter. Duct short. 

10. Penial comjilex of half-grown animal, shell 14.5 mm. in diameter. 

11. Penial complex of another half-grown specimen, shell 14.5 mm. in diameter. 

12. Penial complex of specimen almost adult, shell 16 mm. in diameter. 

13. Penial complex of adult animal, shell 23 mm. in diameter. Duct long, uncoiled. 

14-18. Helisoma corpulentum vermilionense F. C. Baker. From Lake Vermilion, Min- 
nesota; collected by F. C. Baker. 

14. Penial complex showing preputium pushed upward. Duct imcoiled. 

15. Section of penial gland showing cup and penial gland duct. 

16. Penial complex, specimen about one-fourth grown. 

17. Penial complex in specimen somewhat older than fig. 16. 

18. Penial complex of animal about half-grown. Verge of different shape. 

19. Helisoma whiteavesi F. C. Baker. From Mille Lacs, Ontario, Canada; collected 
by A. R. Cahn. 

19. Penial complex with small vergic sac, the penial gland duct uncoiled. 

20-22. Helisoma magnificiun (Pilsbry). From Greenfield Pond, 1 mile south of Wil- 
mington, North Carolina; collected by Dr. Paul Bartsch. 

20. Penial complex with penial gland duct uncoiled. 

21. Penial complex in section. 

22. Penial gland in section. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 299 




PLATE 31 



300 The Molluscan Family Planorbidae 



PLATE 32 

Helisoma 

1-7. Helisoma tenue californiense F. C. Baker. From pools from artesian wells, near 
Shandon, California; collected by Dr. G. D. Hanna. 

1. Genitalia dissected and organs separated. 

2. Penial complex cut open to show verge. 

3. Penial complex with vergic sac at summit of preputium. 

4. Pseudobranch, pneumostome, and rectum. 

5. Penial gland viewed from the outside. 

6. Section of prostate and uterus. 

7. Penial complex with penial gland duct uncoiled. From Prospect Park, Red- 

lands, California; collected by Dr. S. S. Berry. 

8. Helisoma subcrenatum (P. P. Carpenter). Variety. From Pass Lake, Fidalgo 
Island, Puget Sound, Washington; collected by J. Henderson. 

8. Penial complex with preiiutium pushed upward. 

9,10. Helisoma occiclentale (Cooper). From Wacos Bay, Klamath Lake, Oregon; 
collected by J. Hendenson. 

9. Position of verge in vergic sac. 

10. Penial complex with preputium pushed ujjward. 

11-17. Helisoma traskii (Lea). From slough near Kern River, three miles northeast 
of Bakersfield, California; collected by L. G. Ingles. 

11. Penial complex cut open to show form of penial gland. 

12. Cross section through prostate, uterus, and nidamental gland. 

13. Section through penial gland. 

14. Penial complex in normal position with penial sland duct uncoiled. 

15. Pseudobranch, pneumostome, and rectum. 

16. Bifid tentacle. 

17. Genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 301 




PLATE 32 



302 The Molluscan Family Planorhidae 



PLATE 33 

Helisoma 

1-7. Helisoma duryi eiidiscus Pilsbiy. From Silver Springs, Florida; collected by T. 
Van Hyning. 

1. Penial complex showing swollen duct of penial gland and position of verge in 

vergic sac. 

2. Penial complex from exterior with penial gland duct uncoiled. 

3. Penial gland in section showing the long, shallow cup. 

4. Exterior view of penial gland. 

5. Penial complex with preputium pushed upward. 

6. Penial complex of immature specimen, shell 6.5 mm. in diameter. 

7. A very wide example of penial complex. 

8-10, 12, 16-19. Helisoma duryi normale Pilsbry. 

8. Penial complex. From near Paines Prairie, Gainesville, Florida; collected by 

T. Van Hyning. 

9. Penial complex with swollen preputium. From Santa Fe River, High Springs, 

Alachua Co., Florida; collected by T. Van Hyning. 

10. Penial gland in section. Same locality as fig. 9. 

12. Penial complex. Variation in form. From Tamiami Trail, 40 miles west of 

Miami, Florida; collected by W. F. Shay. 

16. Head and neck with penial gland protruding from male opening. Same locality 

as fig. 12. 

17. Penial complex. A normal form showing short penial gland duct. Same 

locality as fig. 12. 

18. Penial complex. A very wide example. Same locality as fig. 12. 

19. Penial gland of half-grown specimen. From near Gainesville, Florida. 

11,13,14. Helisoma duryi (Wetherby), near typical form. Same locality as fig. 12. 

11. Penial gland, partly contracted. 

13. Penial complex with penial gland protruding from male opening. 

14. Penial complex of normal specimen. 

15. Helisoma duryi normale Pilsbry, varying toward intercalare (Pilsbry). 

15. Genitalia dissected and organs separated. From canal at Boynton, Florida; 

collected by W. F. Shay. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 303 




304 The Molluscan Family Planorbidae 



PLATE 34 

Carinifex ponsonbyi E. A. Smith 
From Upper Klamath Lake, Oregon; collected by J. Henderson. 

1. Head and foot showing pseudobranch and pneumostome. 

2. Penial complex showing muscle system and short penial gland duct. 

3. Penial complex cut open to show verge and penial gland. 

4. Genitalia dissected and organs separated. Shows unusual position of spermatheca. 

5. Albumen gland from below. 

6. Portion of genitalia showing relationship of oviduct, sperm duct, ovisperm duct. 

and duct to albumen gland. 

7. Cross section of prostate and uterus. 

8. Cross section of prostate near distal end. 

9. Cross section of ovotestis near proximal end. 

10. Section through penial gland to show duct and folds. 

IL Vagina and spermatheca of different form. 

12. Cross section of preputial sac to show ^'ertical ridges or pilasters. 

Line near figure indicates 1 mm. in length. Figure 12 has 
same magnification as fig. 2. 



Illustrations of the Anatomy and of Shells 305 




PLATE 34 



306 The Molluscan Family Planorbidae 



PLATE 35 

Carinifex 

1. Carinifex ponsonbyi E. A. Smith. From Upper Klamath Lake, Oregon. 

1. Penial complex showing variation in muscle system. 

2-9. Carinifex jackso7iensis J. Henderson. From Jackson Lake, Wyoming; collected 
by J. Henderson. 

2. Simimit of verge showing attachment of retractor muscles. 

3. Penial complex showing multiplication of retractor muscles and short penial 

gland duct. 

4. Pseudobranch and pneumostome. 

5. Genitalia dissected and organs separated. 

6. Portion of genitalia showing relationship of oviduct, sperm duct, ovisperm 

duct, etc. 

7. Same organs as in fig. 6, from above. 

8. Albumen gland. 

9. Another form of spermatheca. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 307 




PLATE 35 



308 The Molluscan Faiyiily Planorbidae 



PLATE 36 

Parapholyx 

1-9,11,12. Parapholyx ej]usa klamathcnsis F. C. Baker. From Upper Klamath Lake, 
Oregon; collected by J. Henderson. 

1. Whole animal removed from shell. 

2. Pseudobranch and related organs. 

3. Genitalia dissected and organs separated. 

4. Cross section of prostate, uterus, and nidamental gland. 

5. Cross section of ovotestis about midway of its length. 

6. Cross section of ovotestis toward posterior end. 

7. Penial complex showing retractor muscles and short penial gland duct. 

8. Penial complex showing nerve and blood vessels. 

9. Penial complex cut open to show verge and penial gland with its short duct. 

At X gland is cut open to show canal. 

11. Section of penial gland showing pipe-like cup and canal. 

12. Verge showing central position of exit for the sperm canal. 

10. Parapholyx cffusa diagonalis J. Henderson. From Crater Lake, Oregon; collected 
by J. Henderson. 
10. Vergic sac and upper part of preputium showing \-erge, muscular ring or dia- 
phragm, and entrance of penial gland duct into diaphragm. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 309 




PLATE 36 



310 The Molluscan Family Planorbidae 



PLATE 37 

Planorhula armigera (Say) 

From Murphy Creek swamp, near Madison, Wisconsin; 
collected by J. E. Morrison. 

1. Section of prostate near middle of gland. 

2. Section of prostate near middle. 

3. Portion of genitalia showing relationship of o\iduct, sperm duct, ovisperm duct, 

and carrefour. 

4. Genitalia dissected and organs separated, with albumen gland in natural position. 

5. Head and foot showing pseudobranch and pneumostome. 

6. Section of penial gland. 

7. Section of ovotestis to show paired condition of diverticula, which are e.xtended 

laterally, appearing as though digitate. 

8. End of verge to show outlet of sperm canal. 

9. Penial complex showing muscles and general form of vergic sac and preputium. 

10. Penial complex of small, immature specimen showing wide form of preputium. 

11. Section of penial complex showing penial gland spread out and opened, with a 

short, internal duct. 

12. Verge in vergic sac. 

Line near figure indicates 1 mm. in length. Long line at left of plate is for 
figs. 6, 7, and 8. Long line at right of plate is for figs. 1 and 2. 



Illustrations of the Anatomy and of Shells 311 




PLATE 37 



312 The MoUuscan FainUy Planorbidae 



PLATE 38 
Menetus 

1,2,4-10. Menetus opercularis (Gould). From Mountain Lake, San Francisco, Cali- 
fornia; collected by H. Walton Clark. 

1. Genitalia dissected and organs separated. 

2. Section of prostate near distal end. 

4. Head showing position of pseudobranch. 

5. Section of ovotestis. 

6. Penial gland with cup expanded. 

7. Albumen gland. 

8. Section through penial complex showing natural position of penial gland. 

9. Albumen gland in natural position overlying stomach. 

10. Exterior view of penial complex. 

3,11-15. Menetus cooperi calUughjptus (Vanatta). From Crescent City, California; 
received from Dr. G. D. Hanna. Also from Quatsino Sound, British Columbia; 
collected by A. Peake. 

3. Section of prostate about midway of its length. California sjiecimen. 

11. Penial complex from the outside. California specimen. 

12. Penial complex. British Columbia specimen. 

13. Entire prostate. British Columbia specimen. 

14. Cross section of prostate and uterus near front end. British Columbia specimen. 

15. End of verge showing central outlet of sperm canal. British Columbia specimen. 

Line near figure indicates 1 mm. in length. Line at left of fig. 10 is also for 
figs. 7 and 8. Line at left of fig. 14 is also for figs. 2, 3, 5, 6, 14, and 15. 



Illustrations of the Anatomy and of Shells 313 




314 The MoUuscan Family Planorhidae 



PLATE 39 

Menetus 

1-6,9,10. Menetus cooperi callioglyptus (Vanatta). From Quatsino Sound, Vancouver 
Island, British Columbia; collected by Arthur Peake. Also from Crescent City, 
California. See plate 38. 

1. Genitalia dissected and organs separated. California specimen. 

2. Head showing form of jiseudobranch. California specimen. 

3. Penial complex in natural position under female complex. British Columbia 

specimen. 

4. Head showing pseudobranch. California specimen. 

5. Penial gland attached to wall of preputium. California specimen. 

6. Seminal vesicle and ovisperm duct. California specimen. 

9. Penial complex showing enlargement of vas deferens as it enters the vergic sac 

to form an epiphallus. Also form of penial gland in preputium. 
10. Penial complex of specimen badly infested with Trematode worms (flukes). 
Note peculiar form. British Columbia specimen. 

7,8. Menetus cooperi F. C. Baker {= planulat us Cooper, preoccupied). From Orcas 
Island, Puget Sound, Washington; collected by Dr. T. Dale Foster. 

7. Penial complex cut open to show verge, penial gland with its short, internal 

duct, enlargement of \as deferens (epiphallus), and position of retractor 
muscle. 

8. Penial gland in section. 

Line near figure indicates 1 mm. in length. Line above fig. 6 is also 
for figs. 5 and 8. Line near fig. 9 is also for fig. 7. 



Illustrations of the Anatomy and of Shells 315 




PLATE 39 



316 The Molluscan Family Plauorhidae 



PLATE 40 

Menetus 

3-5, 7, 9, 12. Menetus dilatatus (Gould). From pond in field near Unionville, Connecti- 
cut; collected b.y F. C. Baker and Leslie Brewer. Also from Hyannis, Massa- 
chusetts; collected by F. C. Baker. 

3. Penial complex with preputium pushed u]>waid. 

4. Penial complex in natural position, the preputium inflated. 

5. Penial complex shown in fig. 4 cut open to show position of verge and i)enial 

gland. 

7. Pseudobranch of specimen from Hyannis, Massachusetts. A broad form. 
9. Pseudobranch of specimen from Union\iIle. 

12. Genitalia dissected and organs separated. Small specimen shows re\erse side 
of prostate and vas deferens. 

1,2,6,8, 10, 11. Menetus sampsoni (Ancey). From six miles northeast of Dallas, Texas; 
collected by Dr. E. P. Cheatum. Also from Meremac River, near Stanton, 
Missouri; collected by Leslie Hubricht. 

1. Ovisperm duct and seminal vesicle. Missouri specimen. 

2. Penial gland. Texas specimen. 

6. Diverticulum of ovotestis with ova in upper part. Texas specimen. 

8. Pseudobranch in cylindrical form. Texas specimen. 

10. Penial complex cut open to show verge and form of i)enial gland. Texas 

specimen. 

11. External view of penial complex. Texas form. 

Line at left of fig. 12 equals 1 mm. in length. Line at right of fig. 10 
equals 0.5 mm. in length. All figures are greatly enlarged. 



Illustrations of the Anatomy and of Shells 317 




PLATE 40 



318 The Molluscan Family Planorbidae 



PLATE 41 

Promenetus exacuous (Say) 
From Winnebago Lake, near Oshkosh, Wisconsin; collected by F. C. Baker. 

L Penial complex. Swollen gland causing bulge in preputium. 

2. Penial complex, external view, showing a single retractor muscle. 

3. Penial complex opened to show verge and penial gland. 

4. Cross section of ovotestis about midway of its length. 

5. Cross section of prostate near anterior end. 

6. Ovotestis viewed from left side of animal, showing diverticula. 

7. Albumen gland from the side. 

8. Head and neck of animal showing pseudobranch. 

9. Head of animal showing verge and jienial gland ]>rojecting from the male genital 

opening. 
10. Genitalia dissected and organs separated. 

Line near figure indicates 1 mm. in length. Line at left of figs. 4 and 5 is for 
both of these figures. Figure 7 has the same magnification as fig. 10. 



Illustrations of the Anatomy and of Shells 319 




PLATE 41 



320 The Molluscan Family Planorbidae 



PLATE 42 

Promenetus 

1,3,7,12. Promenetus exacuous (Say). From Mott Lake, Wainwright Park, Alberta; 
collected by Dr. Stiles. Received from Canadian National Museum. 

1. Pseudobranch fully expanded. 

3. Penial gland in preputium which has been cut open and the pilasters separated. 

7. Section of penial gland. 

12. Side view of preputium showing penial gland and end of verge passing through 

the diaphragm. 

2,4,5,8-11,13. Promenetus exacuous megas (Dall). From Paul Lake, British Colum- 
bia; collected by Dr. D. S. Rawson. 

2. Head of animal showing pseudobranch. 

4. Penial gland from above showing trough-like duct leading to muscular ring 

or diaphragm at upper part of preputium. 

5. Penial complex in natural position. 

8. Cross section of ovotestis near middle. 

9. Cross section of ovotestis near posterior end. 

10. Portion of genitalia showing relation.ship of ducts. 

11. Cross section of prostate. An unusual form with split diverticula. 

13. Terminal end of verge showing central exit for sperm canal, small fleshy ap- 

jiendage, and peculiar ring near end. 

6. Promenetus umbilicatcUus (Cockerell). From Wainwright Park, Alberta; collected 
by Dr. Stiles. Received from Canadian National Museum. 

6. Pseudobranch and jineumostome. 

Line near figure indicates 1 mm. in length. Vertical line bordering 
figs. 8, 9, and 13 is also for figs. 7, 10, and 11. 



Illustrations of the Anatomy and of Shells 321 




322 The Molluscan Family Planorbidae 



PLATE 43 

Pronienetus umbilicatellus (Cockerell) 

From lake southwest of Mott Lake, Wainwright Park, Alberta; collected by 
Dr. Stiles. Received from the Canadian National Museum. 

L Genitalia dissected and organs separated. 

2. Head showing pseudobranch and pneumostome. 

3. Penial complex opened to show penial gland, verge, diaphragm, etc. 

4. Penial complex in natural position. 

5. Albumen gland from below. 

6. Cross section of prostate and uterus about midway of length. 

7. Portion of genitalia showing union of oviduct and sperm duct, also carrefour. 

8. Cross section of ovotestis. Note developing ova. 

9. Penial gland showing channel-like duct, viewed from above. 

10. Penial gland viewed from the side showing how gland is folded and base attached 

to preputium at lower end. 

11. Section of penial gland. 

12. Termination of \erge showing small fleshy appendage at end. 

Line near figure indicates 1 mm. in length. Figures 5, 6, 7, and 8 have 

same measurements as fig. 1. Figures 9. 10, 11, and 12 

have same measurements as fig. 3. 



Illustrations of the Anatomy and of Shells 323 




324 The Molluscan Family Planorbidae 



PLATE 44 

Kidney of Helisoma 

1. H. anceps (Menke). Gillespies Pond, Collinsville, Connecticut. 

2. H. trivolvis (Say). Oneida Lake, New York. 

3. H. corpulcntum (Say). Lake of the Woods, Ontario, Canada. 

4. H. scalare (Jay). Lake Butler, Florida. 

5. H. duryi normale Pilsbry. Canal at Boj-nton, Florida. 

Sections of kidneys 

6. H. oregonense (Tryon). Tooele Co., Oregon. Near lower end of kidney. 

7. H. anceps (Menke). Gillespies Pond. Collinsville, Connecticut. Above middle. 

8. H. a. latchfordi (Pilsbry). Meach Lake, Quebec, Canada. Near middle. 

9. H. trivolvis (Say). Oneida Lake, New York. About middle. 

10. H. t. macrostomum (Whiteaves). Bayfield, Wisconsin. About middle. 
IL H. t. lentum (Say). New Orleans, Louisiana. Lower end. 

12. H. pilsbryi (F. C. Baker). Lake Chetek, Wisconsin. Near Middle. 

13. H. truncatum (Miles). Winnebago Lake, Wisconsin. Near middle. 

14. //. magnificum (Pilsbry). Near Wilmington, North Carolina. Near middle. 

15. H. corpulentuyn (Say). Lake of the Woods, Ontario. Near middle. 

16. H. c. multicostntum F. C. Baker. Crooked Pine Lake, Ontario. Lower end. 

17. H. p. infracarinatum F. C. Baker. Basswood River Rapids, Ontario. At middle. 

18. H. occidentale (Cooper). Klamath Lake, Oregon. Near middle. 

19. H. o. depressum F. C. Baker. Klamath Lake, Oregon. Near middle. 

20. //. (raskii (Lea). Buena Vista Canal, California. Near middle. 

21. H. subcrenatnm (P.. P. Carpenter). McMurray, Skagit Co., Washington. Near 

middle. 

22. H. plexatum (Inger.soll). Columbine Lake, Colorado. Lower end. 

23. H. horni (Tryon). Paul Lake, British Columbia. Near middle. 

24. H. tenue calij orniense F. C. Baker. Shandon, California. Near middle. 

25. H. scalare (Jay). Lake Butler, Florida. Near middle. 

26. H . duryi normale Pilsbry. Canal at Boynton, Florida. Near middle. 

Line near figure indicates 1 mm. in length. Arrow indicates 
point at which section was made. 



lUustratioiis of the Anatomy and of Shells 325 




PLATE 44 



326 The Molluscan Family Planorbidae 



PLATE 45 

Kidneys of Planorbidae 

1. Australorbis glabratus (Say). Puerto Rico. 

2. Carinifex pojisonbyi E. A. Smith. Klamath Lake, Oregon. 

3. Planorbula armigera (Say). Near Oshkosh, Wisconsin. 

4. H. tenue californiense F. C. Baker. Near Redlands, California. 

5. H. tenue californiense F. C. Baker. Section at B in fig. 4. 

6. H. tenue californie7i.se F. C. Baker. Section at A in fig. 4. 

7. Australorbis glabratus (Say). Section at E in fig. I. 

8. Australorbis glabratus (Say). Section at D in fig. I. 

9. Australorbis glabratus (Say). Section at C in fig. L 
10. Australorbis glabratus (Say). Section at B in fig. L 
IL Australorbis glabratus (Say). Section at A in fig. L 

12. Carinifex ponsonbyi E. A. Smith. Section near middle. 

13. Planorbula armigera (Say). Section near middle. 

14. Four spherical bodies from ridge of kidney. Greatly enlarged. 

15. Helisoma campanulatum wisconsinense (Winslow). Section through upper part. 

16. H. campanulatum. wisconsinense (Winslow). Section through middle. 

17. H. campanulatum wisconsinense (Winslow). Section through lower end. 

18. Planorbarius corneus (Linn.). Section through lower end. From Poland. 

19. Indoplanorbis exustus (Deshayes). Section near middle. From India. 

Line near figure indicates 1 mm. in length. Letters A, B, C, D, E, etc., 

indicate points of kidney through which sections have 

been made and are figured. 



Illustrations of the Anatomy and of Shells 

IN 



327 




PLATE 45 



328 The Molluscan Family Planorbidae 



PLATE 46 

Kidneys of Planorbidae 

1. Parapholyx effusa klamathensis F. C Baker. Klamath Lake, Oregon. 

2. P. effusa klamathensis F. C. Baker. Section near middle. 

3. Promenetus exaciious (Say). Winnebago Lake, near Oshkosh, Wisconsin. 

4. Promenetus exacuous (Say). Section near middle. Line is 0.3 mm. long. 

5. Menetus dilatatus (Gould). Unionville, Connecticut. 

6. Menetus dilatatus (Gould). Section near middle. Line is 0.3 mm. long. 

7. Menetus cooperi callioglyptus (Vanatta). Vancouver Island, British Columbia. 

8. M. cooperi callioglyptus (Vanatta). Section near middle. 

9. Planorbis planorbis (Linn.). Near Warsaw, Poland. 
10. Planorbis planorbis (Linn.). Section near middle. 
n. Tropicorbis riisei (Dunker). Puerto Rico. 

12. Tropicorbis riisei (Dunker). Section near middle. 

13. Tropicorbis havanensis (Pfeiffer). Section near middle. 

14. Drepanotrema hoffmani F. C. Baker. Lsabela, Puerto Rico. 

15. Drepanotrema hoffmani F. C. Baker. Section at ])oint indicated by arrow. 

16. Drepanotrema lucidum (Pfeiffer). Section near middle. 

17. Hippeutis complanatus (Linn.). Near Warsaw, Poland. 

18. Hippeutis complanatus (Linn.). Section at point indicated by arrow. Line equals 

0.5 mm. in length. 

19. Bathyomphalus contortus (Linn.). Near Warsaw, Poland. 

20. Bathy<>mi>halus contortus (Linn.). Section at jioint indicated by arrow. Line 

equals 0.5 mm. in length. 

Except where otherwise mentioned the line near the figure 
indicates 1 mm. in length. 



Illustrations of the Anatomy and of Shells 



329 




330 The Molluscan Family Planorbidae 



PLATE 47 

Kidneys of Planorbidae 

1. Gyraulus parvus (Say). Winnebago Lake, Wisconsin. 

2. Gyraulus circumstriatus (Tryon). Wainwright Park, Alhoifa. 

3. Gyraulus deflcctus ohliquus (DeKay). Near Quebec, Canada. 

4. Gyraulus vermicularis (Gould). Near San Francisco, California. 

5. Gyraulus parvus (Say). Section near middle. Line equals 0.5 mm. 

6. Gyraulus circumstriatus (Tryon). Section near middle. Line equals 0.5 nmi. 

7. Gyraulus vermicularis (Gould). Section near middle. Line equals 0.5 nun. 

8. Gyraulus convexiusculus (Hutton). India. Section near middle. 

9. Gyraulus siniilarls (F. C. Baker). Section near middle. 

10. Gyraulus deflcctus obliquus (DeKay). Section near middle. 
IL Gyraulus latestornus F. C. Baker. Section below middle. 

Figures 6 to 11 have same magnification as fig. 5. 

12. Anisus vortex (Linn.). Near Wansaw, Poland. 

13. Ayiisus spirorbis (Linn.). Near Warsaw, Poland. 

14. Ayiisus vortex (Linn.). Section near middle. Line equals 0.5. mm. 

15. Anisus leucoslomus (Millet). Section near middle. Line equals 0.5 mm. 

16. Anisus spirorbis (Linn.). Section near middle. Line equals 0.5 mm. 

17. Gyraulus convexiusculus (Hutton). India. 

18. Gyraulus hirsutus (Gould). Canada. 

19. Gyraulus hirsutus (Gould). Section below middle. 

20. Armiger crista (Linn.). Wi.sconsin. 

21. Anniger crista (Linn.). Section near middle. Line equals 0.5 nnu. 

22. Segmenlina nilida (Miiller). Near Warsaw, Pohmd. 

23. Segmentina nitida (Miiller). Section below middle. Line equals 0.5 nun. 

24. Polypylis hemisphaerula (Benson). Peiping, China. 

25. Polypylis hemisphaerula (Benson). Section near middle. Line equals 0.5 mm. 

26. Intha capitis Annandale. South Shan State, Burma. 

27. Intha capitis Annandale. Section below middle. Line equals 0.25 mm. 

Linless otherwi.se stated the line near the figure indicates 1 nun. ni length. 



Illustrations of the Anatomy and of Shells 



331 




PLATE 47 



332 The Molluscan Family Planorhidae 



PLATE 48 

Digestive System of Planorbidae 

1. Helisoma trivolvis (Say). Entire digestive system except liver. From above. 

2. Helisoma trivolvis (Say). Region of the stomach from below. 

3. Carinifex ponsonbyi E. A. Smith. Region of stomach from below. 

4. Promenetus exacuous (Say). Region of stomach from above. 

5. Promenetus exacuous (Say). Region of stomach from below. 

6. Planorbis planorbis (Linn.). Region of stomach from above. 

7. Planorbis planorbis (Linn.). Region of stomach from below. 

8. Bathyomphalus contortus (Linn.). Portion of digestive system from above. 

9. Atistrnlorbis glabratns (Say). Region of stomach from above. 
10. AuMralorbis glabratus (Say). Region of stomach from below. 

IL Drepanotrema hicidum (Pfeiffer). Region of stomach from above. 

12. Hippeutis complanatus (Linn.). Region of stomach from above. 

13. Gyraulus albus (Miiller). Region of stomach from above. 

14. Gyraulus parvus (Say). Region of stomach from above. 

15. Armiger crista (Linn.). Region of stomach from above. 

16. Segmentina nitida (Miiller). Region of stomach from above. 

17. Helisoma anceps (Menke). Nerves and blood vessels to penial complex. Nerve 

from left cerebral ganglion. 

18. Nerve ring of Helisoma trivolvis (Say), from above. 

Line near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 333 




PLATE 48 



334 The Molluscan Family Planorbidae 



PLATE 49 

Jaws of Planorbidae 

1. Helisoma anceps (Menke). Chetek Lake, Wisconsin. 

2. Helisoma trivolvis (Say). Devils Lake, Wisconsin. Small fig. indicates striation. 

3. Helisoma truncatum (Miles). Oshkosh, Lake Winnebago, Wisconsin. 

4. Helisoma scalare (Jay). Lake Butler, Florida. 

5. Helisoma pilsbryi (F. C. Baker). Chetek Lake, Wisconsin. 

6. Helisoma oregojiense (Tryon). Tooele Co., Utah. 

7. Helisoma subcrenatum (P. P. Carpenter). Gypsum, Colorado. Superior jaw. 

8. H. pilsbryi injracarinatum F. C. Baker. Rideau River, Ontario. Superior jaw. 

9. Helisoma horni (Tryon). Paul Lake, British Columbia. 

10. Helisoma plexatum (Ingersoll). Grand Mesa, Colorado. Superior jaw. 
IL H. campanulatum smithi (F. C. Baker). Douglas Lake, Michigan. 

12. Helisoma traskii (Lea). Outlet of Kern Lake, California. Superior jaw. 

13. Helisoma occidentale (Cooper). Klamath Lake, Oregon. Superior jaw. 

14. H. duryi normale Pilsbry. Forty miles west of Miami, Florida. Superior jaw. 

15. Helisoma corpulentum (Say). Bamiji Lake, Ontario, Canada. 

16. Helisoma magnificum (Pilsbry). Near Wilmington, North Carolina. 

17. Carinifex jacksonejisis J. Henderson. Jackson Lake, Wyoming. Jaw and cartilage 

from the side. 

18. Carinifex jacksonensis J. Henderson. Jaw from above. 

19. Carinifex ponsonbyi E. A. Smith. Klamath Lake, Oregon. Jaw and cartilage from 

below. 

20. Helisoma campatudatum smithi (F. C. Baker). Douglas Lake, Michigan. Vertical 

striation on jaw. Highly magnified. 

Line at right of fig. 1 indicates 1 mm. in length. Line at lower extreme left is 

for figs. 18 and 19 and represents 0.5 mm. in length. Middle line is 

for fig. 6. Line at right is for figs. 2, 3, 4, 5, and 

7 to 16. Figure 17 is diagrammatic. 



Illustrations of the Anatomy and of Shells 335 




336 The Molluscan Family Planorbidae 



PLATE 50 

Jaws of Planorbidae 

1. Helisoma tenae calijornicnse F. C. Baker. Shandon, California. 

2. Planorhiila armigera (Say). Muri)hy Creek, near Madison, Wisconsin. 

3. Pkmorbula jenksii (H. F. Carpenter). Unionville, Connecticut. 

4. Porapholyx effusa klamathensis F. C. Baker. Klamath Lake, Oregon. 

5. Porapholyx effusa diagonalis J. Henderson. Crater Lake, Oregon. 

6. Menetus sampsoni (Ancey). Near Stanton, Missouri. 

7. Menetus cooperi caUioglyptus (Vanatta). Vancouver Island, British Columbia. 

8. Promenetus exacuous (Say). Winnebago Lake, Wisconsin. 

9. Menetus dilatatus (Gould). Unionville, Connecticut. 

10. Indoplanorhis exustus (Deshayes). North Shan State, Burma. 

n. Tropicorbis obstructus (Morelet). New Orleans, Louisiana. Superior jaw. 

12. Tropicorbis riisei (Dunker). Puerto Rico. 

13. Australorbis glabratus (Say). Puerto Rico. 

14. Planorbarius corneus (Linn.). Near Warsaw, Poland. 

15. Promenetus umbilicatellus (Cockerell). Wainwright Park, Alberta. 

16. Gyraulus parvus (Say). Winnebago Lake, Wisconsin. 

17. Gyraulus hirsutus (Gould). Lake Nipissing, Ontario, Canada. 

18. Gyraulus deflectus obliquus (DeKay). Taylor Lake, Quebec, Canada. 

19. Gyrauhis vermicrdaris (Gould). Near San Francisco, California. 

20. Armiger crista (Linn.). Wisconsin. 

21. Planorbis planorbis (Linn.). Near Warsaw, Poland. 

22. Gyraidus circumstriatus (Tryon). Wainwright Park, Alberta. 

23. Intha capitis Annandale. Burma. 

24. Segmentina nitida (Muller). Near Warsaw, Poland. 

25. Ayiisus spirorbis (Linn.). Near Warsaw, Poland 

26. Drepanotrema hoffmani F. C. Baker. Puerto Rico. 

27. Drepanotrema lucidum (Pfeiffer). Cuba. 

28. Gyraulus albus (Muller). Near Warsaw, Poland. 

Figures are greatly enlarged. Sizes are disproportionate. 



Illustrations of the Anatomy and of Shells 337 




PLATE 50 



338 The Molluscan Family Planorbidae 



PLATE 51 

Development of Helisoma scalare (Jay) 

1. Egg capsule containing 28 eggs, observed on March 1, 1932. Each egg is marked 

to correspond with the numbered figures below. Line near figure indicates 1 mm. 
in length. 

2. The 24-cell stage of segmentation in egg No. 7. March 7. 

3. Gastrula stage of segmentation in egg No. 7. March 8. 

4. Post-trochophore stage in egg No. 11. March 4. 

5. Post-trochophore stage in egg No. 11. March 5. 

6. Veliger stage of embryo in egg No. 11. March 9. 

7. Veliger stage of embryo in egg No. 8. Front view. March 9. 

8. Veliger stage of embryo in egg No. 8. Side view. March 9. 

9. Veliger stage of embryo in egg No. 8. Top view. March 10. 

10. Embryo in egg No. 3. March 12. 

11. Embryo in egg No. 1 showing heart and stomach. March 11. 

12. Young snail in egg No. 3. March 14. A similar young snail was observed in egg 

No. 20 on March 14. Shell growth distinct. 

13. Young snail just out of egg No. 1. March 15. 

14. Young snail two days out of egg No. 1. March 16. Shell now shows both growth 

lines and spiral striae. 

Line at lower left indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 



339 




340 The Molluscan Family Planorbidae 



PLATE 52 

Nidifieation in Planorbidae 

1-3. Helisoma scalare (Jay). Lake Butler, Florida. 
L Five eggs laid March 13, 1931. 

2. Fourteen eggs laid April 1, 1931. 

3. Ten eggs laid April 2, 1931. 

4-5. Helisoma trivolvis lentum (Say). New Orleans, Louisiana. 

4. Twenty eggs laid June 5, 1933. 

5. Ten eggs laid May 27, 1933. 

6-8. Helisoma eluryi normale Pilsbry. Gainesville, Florida. 

6. Two eggs laid Dec. 25, 1931. 

7. Three eggs laid Dec. 26, 1931. 

8. Four eggs laid Jan. 17, 1932. 

9-11. Helisoma duryi cudiscus Pilsbry. Silver Springs, Florida. 

9. Five eggs laid Dec. 13, 1931. 

10. Nine eggs laid Feb. 6, 1932. 

11. Twelve eggs laid Feb. 10, 1932. 

12. Helisoma duryi normale Pilsbry. Tamiami Trail, 40 miles west of Miami, Florida. 

12. Sixteen eggs laid Jan. 17, 1932. 

13. Helisoma traskii (Lea). Buena Vista Canal, outlet of Kern Lake, California. 

13. Alcoholic specimen wath 50 eggs laid on adult shell. 

14-16. Gyraulus circumstriaius (Tryon). Wainwright Park, Alberta. 

14. Nucleated ovum from ovotestis. 

15. Spermatozoa from o\otestis. Typical (eupyrene) spermatozoa as seen in 

active group. 

16. Eupyrene spermatozoa from the side and from abo\'e. 

Line near figs. 1-13 indicates 1 mm. in length. Line near figs. 14-16 
indicates 25 microns in length. 



Illustrations of the Anatomy and of Shells 341 




PLATE 52 



342 The Molluscan Family Planorbidae 



PLATE 53 

Radulae of Helisotna 

In the plates of radulae, the number under the central tooth (as 15, 80, 98, 50, and 75 
on this plate) indicates the number of the transverse row, counting from the front 
end of the radula. The numbers following indicate the number of the tooth in this 
row, counting from the central tooth, the first lateral tooth being nvuiiber 1. The line 
at the lower part of the plate indicates 25 microns. 

1. Helisoma anceps (Menke). Maple River, Michigan. 

15, center tooth; 1-5, lateral teeth; 6, 7, intermediate teeth; 8-14, marginal teeth. 

2. Helisoma anceps (Menke). Chautauqua Lake, New York. 

80, center tooth; 1-5, lateral teeth; 6-8, intermediate teeth; 9-13, marginal teeth. 
118, center tooth (of 118th row) with first left marginal beside it. 

3. Helisoma anceps (Menke). Unionville, Connecticut. 

98, center tooth; 1, 2, lateral teeth; 6, 7, intermediate teeth; 8, 9, marginal teeth 
on right side; 11-16, marginal teeth on left side of row. 90, 90th row, center 
tooth; 5, lateral tooth with two ectocones; 8, intermediate tooth; 9, 10, 
marginal teeth. 

4. HcILsoma anceps sayi F. C. Baker. Bayfield, Wisconsin. 

50, center tooth in 50th row; 1-5, lateral teeth; 6, 7, intermediate teeth; 8-14, 
marginal teeth. 75, 75th row, pathologic center tooth; 1-5, pathologic lateral 
teeth. 



Illustrations oj the Anatomy and of Shells 343 




PLATE 53 



344 The Molluscan Family Planorbidae 



PLATE 54 

Radulae of Helisoma 

See remarks on plate 53. Line at bottom of plate indicates 
25 microns in length. 

L Helisoma nnceps percarinatum (Walker). Douglas Lake, Michigan. 

85, center tooth; 1-6, lateral teeth; 7-9, intermediate teeth; 10-23, marginal teeth. 
100, 100th row, center tooth; 1-3, lateral teeth, pathologic (2 entocones) ; 
9, intermediate tooth; 10, marginal tooth. 

2. Helisoma anceps royalense (Walker). Bamiji Lake, Ontario, Canada. 

60, center tooth; 1-6, lateral teeth; 7-9, intermediate teeth; 10-19, marginal 
teeth. 

3. Helisoma anceps cahni F. C. Baker. Big Muskallonge Lake, Wisconsin. 

60, center tooth; 1-6, lateral teeth; 7-9, intermediate teeth; 10-18, marginal teeth. 

4. Helisoma anceps latchjordi (Pilsbry). Meach Lake, Quebec, Canada. 

51, center tooth; 1-6, lateral teeth; 7-9, intermediate teeth; 10-26, marginal teeth. 
60, an abnormal center tooth from another membrane, with accessory lateral 
cusps above the normal center cusps. 



Illustrations of the Anatomy and of Shells 345 




346 The Molluscan Family Planorbidae 



PLATE 55 

Radulae of Helisoma 
See remarks on plate 53. Line at bottom of plate indicates 25 microns in length. 

1. Helisoma trivolvis (Say). Oneida Lake, New York. 

60, center tooth; 1-7, lateral teeth; 8-10, intermediate teeth; 11-18, marginal 
teeth. 

2. Helisoma trivolvis {Sa.y) ^ pseudotrivolvis F. C. Baker, near lentum Say. From 

Reelfoot Lake, Tennessee. 
150, center tooth; 1-7, lateral teeth; 8-10, intermediate teeth; 11-13, marginal 
teeth. 

3. Helisoma trivolvis lejitum (S&y) ^ pseudotrivolvis F. C. Baker. Reelfoot Lake, 

Tennessee. 
107, center tooth; 1-7, lateral teeth; 8-10, intermediate teeth; 11-14, marginal 
teeth; 50, 50th center tooth of another row. 

4. Helisoma trivolvis (Say). Sturgeon Bay, Wisconsin. 

70, center tooth; 1-6, lateral teeth; 7-11, intermediate teeth; 13, 14, marginal 
teeth. 

5. Helisoma chautauquense F. C. Baker. Chautauqua Lake, New York. 

102, center tooth; 1-7, lateral teeth; 8-11, intermediate teeth; 12-15, marginal 
teeth. 

6. Helisoma trivolvis lentum (Say). New Orleans, Louisiana. 

96, center tooth; 1-8, lateral teeth; 9-11, intermediate teeth; 12-15, marginal 
teeth. 

7. Helisoma trivolvis lentum (Say). New Orleans, Louisiana. 

16-25, marginal teeth; 4, 4th lateral tooth from another row, with two entoconic 
cusps. 



Illustrations of the Anatomy and of Shells 347 




11 12 1 



^^150 I 2 3 4^-~~— ^ 1234 




PLATE 55 



348 The Molluscan Family Plauorbidae 



PLATE 56 

Radiilae of Helisoma 
See remarks on plate 53. Line at bottom of plate indicates 25 microns in length. 

1. Helisoma winsloivi (F. C. Baker). Little Arbor Vitae Lake, Wisconsin. 

70, center tooth; 1-13, lateral teeth; 14, 15, intermediate teeth; 17-19, marginal 
teeth. 

2. Helisoma trivolvis macrostovium (Whiteaves). Bayfield, Wisconsin. 

53, center tooth; 1-8, lateral teeth; 9-13, intermediate teeth; 14-23, marginal 
teeth. 

3. Helisoma pilsbryi (F. C. Baker). Chetek Lake, W'isconsin. 

100, center tooth; 1-8, lateral teeth; 10-12, intermediate teeth; 13-23, marginal 
teeth. 

4. Helisoma pilsbryi infracarinatiim F. C. Baker. Basswood River Rapids, Ontario. 

132, center tooth; 1-9, lateral teeth; 10-14, intermediate teeth; 15-21, marginal 
teeth. 

5. Helisoma pilsbryi injracarinatnm F. C Baker. Rideau River, Ontario. 

Varying toward pilsbryi. 115, center tooth; 1-13. lateral teeth; 14. 15, interme- 
diate teeth; 16-29. marginal teeth. 



Illustrations of the Anatomy and of Shells 349 




PLATE 56 



350 The Molluscan Family Planorbidae 



PLATE 57 

Radulae of Helisoma 

See remarks on plate 53. Line at bottom of plate indicates 25 microns in length. 

L Helisoma truncatum (Miles). Winnebago Lake, near Oshkosh, Wisconsin. 

Normal membrane. 85. center tooth; 1-7, lateral teeth; 9-11, intermediate 
teeth; 13-20, marginal teeth. 

2. Helisoma truncatum (Miles). Winnebago Lake, Wisconsin. 

Abnormal membrane, with many split cusps on teeth. 90, center tooth; 1-8, 
lateral teeth, 6 and 7 with bifid entoconic cusps and 5, 6, and 7 with split 
ectoconic cusps; 9-11, intermediate teeth with modified ectocones; 12-21, 
marginal teeth. 

3. Helisoma corpulent um (Say). Lac la Croix, Ontario, Canada. 

48, center tooth; 1-8, lateral teeth; 9-12, intermediate teeth; 13-25, marginal 
teeth. 

4. Helisoma magnijicum (Pilsbry). Near Wilmington, North Carolina. 

90, center tooth; 1-14, lateral teeth; 16-23, intermediate teeth; 24-41, marginal 
teeth. 

The small numerals on the first lateral of fig. 1 indicate the following parts 
of the tooth: 1, entocone or inner cusp; 2, mesocone or middle cusp; 3, 
ectocone or outer cusp; 4, base of attachment to radula membrane. In 16 
of fig. 1, the small numeral 2 indicates the position of the mesocone in a 
marginal tooth. 



Illustrations of the Anatomy and of Shells 351 




16 17 1 



22 25 25 26 27 28 32 41 



PLATE 57 



352 The Molluscan Family Plauorbidae 



PLATE 58 

Radulae of Helisoma 

See remarks on plate 53. Line at bottom of plate indicates 25 microns in length. 

L Helisoma whiteavesi F. C. Baker. Mille Lacs, Ontario, Canada. 

105, center tooth; 1-16, lateral teeth; 17-19, intermediate teeth; 20-35, marginal 
teeth. 23, a pathologic tooth in another row. 12, a lateral tooth on the left 
side with split cusps. 

2. Helisoma corpuhntum vermilionense F. C. Baker. Vermilion Lake, Minnesota. 

101, center tooth; 1-7, lateral teeth; 9-12, intermediate teeth; 13-21, marginal 
teeth. 

3. Helisoma corpulent um inidticostatum F. C. Baker. Kahniinminanikok Lake, 

Ontario, Canada. 
60, center tooth; 1-7, lateral teeth; 11-14, intermediate teeth; 15-41, marginal 
teeth. 

4. Helisoma plexatum (Ingersoll). Teton River, near Rexburg, Idaho. 

44, center tooth; 1-8, lateral teeth, 1 and 4 with mesocones worn or pathologic; 
10-13, intermediate teeth; 13-16, marginal teeth. The two 13 figures show 
how this tooth differed in two rows, being an intermediate tooth in one row 
and a marginal tooth in another row. 

5. Helisoma plexatum (Inger.soll). 

The 120th row in another membrane from a Teton River specimen. 16-18, 
modified marginal teeth. 

6. Helisoma plexatum (Ingersoll). Smartweed Lake, Colorado. 

13, a lateral tooth; 14-15, marginal teeth. 



Illustrations of the Anatoiny and of Shells 353 




PLATE 58 



354 The Molluscan Family Planorbidae 



PLATE 59 

Radulae of Helisoma 
See remarks on plate 53. Line at bottom of plate indicates 25 microns in length. 

1. Helisoma plexatum (Ingersoll). Grand Mesa, Colorado. 

60, center tooth; 1-12, lateral teeth; 13-17, intermediate teeth; 18-22, marginal 
teeth. 

2. Helisoma plexatum (Ingersoll). Columbine Lake, Colorado. 

95, center tooth; 1-10, lateral teeth; 11-12, intermediate teeth; 13-15, marginal 

teeth. 

3. Helisoma tenue calijorniense F. C. Baker. San Bernardino Mts., California. 

Normal teeth. 60, center tooth; 1-11, lateral teeth; 12, 13, intermediate teeth; 
14-21, marginal teeth. 

4. Helisoma tenue calijorniense F. C. Baker. San Bernardino Mts., California. 

Abnormal teeth, the lateral teeth with extra cusps on both entocones and ecto- 
cones and with mesocone much modified. 60, center tooth; 1-10, lateral 
teeth; 11, 12, intermediate teeth; 12-17, marginal teeth. 

5. Helisoma subcrenatum (P. P. Carpenter). Variety. Pass Lake, Puget Sound, Wash- 

ington. 

96, center tooth; 1-15, lateral teeth; 16-18, intermediate teeth; 19-28, marginal 

teeth. 

6. Helisoma tenue calijorniense F. C. Baker. San Bernardino Mts., California. 

An abnormal 11th lateral tooth. 



Illustrations of the Anatomy and of Shells 355 




PLATE 59 



356 The Molluscan Family Planorhidae 



PLATE 60 

Radulae of Helisoma 

See remarks on plate 53. Line at lower rig;ht of plate indicates 
25 microns in length. 

L Helisoma subcrciialum (P. P. Carpenter). Variety. Lost Lake, Paget Sound, 
Washington. 
73, center tooth; 1-7, lateral teeth; 12, 13, intermediate teeth; 15-20, marginal 
teeth. 

2. Helisoma subcrenatum (P. P. Carpenter). Variety. Lost Lake, Puget Sound, Wash- 

ington. 
88, abnormal center tooth; 5. lateral tooth with bicuspid entocone. 

3. Helisoma subcrenatum (P. P. Carpenter). Skagit Co., Washington. 

90, center tooth; 1, 7. lateral teeth; 12, intermediate tooth; 17, 20, marginal teeth. 

4. Helisoma traskii (Lea). Outlet of Kern Lake, California. 

82nd row, 9, intermediate tooth; 10. 11, marginal teeth. 

5. Helisoma traskii (Lea). Outlet of Kern Lake, California. 

90, center tooth; 1-9, lateral teeth; 10, 11, intermediate teeth; 12-22, marginal 
teeth. 

6. Helisoma traskii (Lea). Outlet of Kern Lake, California. 

80th row, 9, intermediate tooth; 10, first marginal tooth. 

7. Helisoma horni (Tryon). Paul Lake, British Columbia. 

60, center tooth; 1-9, lateral teeth; 10-14, intermediate teeth; 15-32, marginal 
teeth. 4, fourth tooth in another row. 



Illustrations of the Anatomy and of Shells 357 




PLATE 60 



358 The Molluscan Family Planorbidae 



PLATE 61 

Radulae of Helisoma 

See remarks on plate 53. Line at lower right of plate 
indicates 25 microns in length. 

1. Helisoma occidentale (Cooper). Klamath Lake, Oregon. 

45, center tooth; 1-8, lateral teeth; 9-12, intermediate teeth; 13-23, marginal teeth. 

2. Helisoma subcrenatum (P. P. Carpenter). Cottonwood Pass, Gypsum, Colorado. 

95, center tooth; 1-8, lateral teeth; 9-12, intermediate teeth; 13-20, marginal teeth. 

3. Helisoma oregonense (Tryon). Tooele Co., Utah. 

58, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-21, marginal teeth. 



Illustrations of the Anatomy and of Shells 359 





C^X ,^ ^^ 18 



3 

PLATE 61 



360 The Molluscan Family Planorbidae 



PLATE 62 

Radiilae of Helisoma 

See remarks on plate 53. Line at lower right of plate 
indicates 25 microns in length. 

L Helisoma campanulatum (Say). Oneida Lake, New York. 

60, center tooth; 1-7, lateral teeth; 8, 9, intermediate teeth; 10-20, marginal teeth. 

2. Helisoma campanulatum. wisconsincnse (Winslow). Little Arbor Vitae Lake, Wis- 

consin. 
50, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-15, marginal teeth. 

3. Helisoma campanulatum canadcnse F. C. Baker. Bamiji Lake, Ontario, Canada. 

52, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-20, marginal teeth. 

4. Helisoma campanulatum smithi (F. C. Baker). Douglas Lake, Michigan. 

60, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-19, marginal teeth. 



Illustrations of the Anatomy and of Shells 361 




362 The Molluscan Family Planorbidae 



PLATE 63 

Radulae of Helisoma 

See remarks on plate 53. Line at lower right of plate 
indicates 25 microns in length. 

1. Helisoma trivolvis fallax (Haldeman). Cambridge, Massachusetts. 

60, center tooth; 1-7, lateral teeth; 10, intermediate tooth; 11-23, marginal teeth. 

2. Helisoma tenue californiense F. C. Baker. Shandon, California. 

77, center tooth; 1-11, lateral teeth; 12. intermediate tooth; 13-19, marginal teeth. 
100th row. Numerals 1-11, lateral teeth with multiple cusps on entocone and 
ectocone. 

3. Helisoma trivolvis lentum (Say). New Orleans, Louisiana. 

60, center tooth; 1-9, lateral teeth; 10, 11, intermediate teeth; 12-20, marginal 
teeth. 

4. Helisoma duryi eudiscus Pilsbry. Silver Springs, Florida. 

84, center tooth; 1-10, lateral teeth; 11, 12, intermediate teeth; 12-22, marginal 
teeth. 



Illustrations of the Anatomy and of Shells 363 




r"^ 



14 15 



17 4 

PLATE 63 



364 The MoUuscan Family Planorbidae 



PLATE 64 

Radulae of Helisoma 

See remarks on plate 53. Line at lower right of plate 
indicates 25 microns in length. 

L Helisoma scalare (Jay). Lake Butler, Florida. 

89, center tooth; 1-8, lateral teeth; 9-11, intermediate teeth; 12-21, marginal teeth. 

2. Helisoma scalare (Jay). Lake Butler, Florida. 

86, center tooth of another specimen; 1-6, lateral teeth. 

3. Helisoma duryi normale Pilsbry. Tamiami Trail, 40 miles west of Miami, Florida. 

110, center tooth; 1-11, lateral teeth; 12, intermediate tooth; 13-29, marginal 
teeth. 12, lower right, 12th tooth (marginal) in another row of teeth. 

4. Helisoma duryi normale Pilsbry. Paines Prairie, Florida. 

55, center tooth ; 1-9, lateral teeth; 10, intermediate tooth; 11-26, marginal teeth. 
140, center tooth; 1-10, lateral teeth; 11, intermediate tooth; 12-20, marginal 
teeth. 



Illustrations of the Anatomy and of Shells 365 




PLATE 64 



366 The Molluscan Family Planorbidae 



PLATE 65 

Radulae of Planorbula, Parapholyx, and Carinifex 

See remarks on plate 53. Line at lower left of plate 
indicates 25 microns in length. 

1. Planorbula armigera (Say). Murphy Creek, near Madison, Wisconsin. 

128, center tooth; 1-6, lateral teeth; 9, 11, intermediate teeth; 12-19, marginal 
teeth. 

2. Planorbula jenksii (H. F. Carpenter). Unionville, Connecticut. 

105, center tooth; 1-5, lateral teeth; 9, 11, intermediate teeth; 12-19, marginal 
teeth. 

3. Parapholyx effusa klamathensis F. C. Baker. Klamath Lake, Oregon. 

60, center tooth; 1-8 lateral teeth; 9-11, intermediate teeth; 13-19, marginal teeth. 

4. Cariyiifex jackso7ic7isi.<i J. Henderson. Jackson Lake, Wyoming. 

120, center tooth; 1-10, lateral teeth; 12, intermediate tooth; 13-24, marginal 
teeth. 



Illustrations oj the Anatomy and of Shells 367 





128 1 2 3 4 <» 9 




/'^:=:) 



368 The Molluscan Family Planorbidae 



PLATE 66 

Radiilae of Indoplanorbis and Planorbarius 

See remarks on plate 53. Line at lower right of plate 
indicates 25 microns in length. 

1. Indoplanorbis exustus (Deshayes). North Shan State, Burma. 

60, center tooth; 1-5, lateral teeth; 6-10, intermediate teeth; 16-21, marginal 
teeth; 11, last intermediate tooth in another row; 12-15, marginal teeth in 
same row; 23-26, marginal teeth in same row; 27, 32, 33, outer marginal teeth 
in same row. 

2. Planorbarius corneus (Linn.). Near Warsaw, Poland. 

60, center tooth; 1-9, lateral teeth; 10-14, intermediate teeth; 15-38, marginal 
teeth; 39-42, outer marginal teeth. 



Illustrations of the Anatomy and of Shells 369 




»* 17 18 



23 25 26 



27 32 33 




PLATE 66 



370 The MoUuscan Family Planorbidae 



PLATE 67 

Radiilae of Planorbidae 

See remarks on plate 53. Line at lower right of plate indicates 25 microns 
in length. Line under fig. 6 is also for figs. 1 to 5. 

1. Promcnetus exacuous (Say). Wainvvright Park, Alberta. 

50, center tooth; 1-6, lateral teeth; 9, 10, intermediate teeth; 11-15, marginal 
teeth. 

2. Promenetus umbilicatcUus (Cockerell). Wainwright Park, Alberta. 

60, center tooth; 1-6, lateral teeth; 9-11, intermediate teeth; 12-15, marginal teeth. 

3. Menetus cooperi caUioglyptus (Vanatta). Vancouver Island, British Columbia. 

55, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-15, marginal 
teeth. 

4. Menetus dilatatus (Gould). Unionville, Connecticut. 

60, center tooth; 1-7, lateral teeth; 8-10, intermediate teeth; 11-14, marginal teeth. 

5. Menetus sampsoni (Ancey). Stanton, Missouri. 

50, center tooth; 1-7, lateral teeth; 8, 10, intermediate teeth; 11-14, marginal 
teeth. 

6. Anisus spirorbis (Linn.). Near Warsaw, Poland. 

45, center tooth; 1-10, lateral teeth; 11, intermediate tooth; 12-15, marginal teeth. 

7. Planorbis planorbis (Linn.). Near Warsaw, Poland. 

60, center tooth; 1-9, lateral teeth; 11, intermediate tooth; 14-20, marginal teeth. 

8. Camiifex ponsonbyi E. A. Smith. Klamath Lake, Oregon. 

115, center tooth; 1-6, lateral teeth; 7-10, intermediate teeth; 11-27, marginal 
teeth. 



Illustrations of the Anatomy and of Shells 371 




10 11 12 '< 



^ 







11 12 ii " 






10 11 12 13 14 





45 1 





^^ts^Ts 



11 12 li 14 




PLATE 67 



372 The Molluscan Family Planorbidae 



PLATE 68 

Radiilae of Planorbidae 

See remarks on plate 53. Line at lower right of plate indicates 25 microns 
in length for figs. 5-9; lines for figs. 1-4 are 10 microns in length. 

1. Bctthyomphalus contortus (Linn.). Near Warsaw, Poland. 

60, center tooth. 

2. Drepcmotrema lucidum (Pfeiffer). Havana, Cuba. 

50, center tooth; 1-8, lateral teeth; 13, 14, intermediate teeth; 15, marginal tooth. 

3. Drepanotrema anatinum (Orbigny). Puerto Rico. 

50, center tooth; 1-5, lateral teeth; 7, 9, intermediate teeth; 13, marginal tooth. 

4. Drepanotrctiia hoffmani F. C. Baker. Puerto Rico. 

52, center tooth; 1-6, lateral teeth; 8, intermediate tooth; 11-21, marginal teeth. 

5. Australorbis glabratus (Say). Puerto Rico. 

60, center tooth; 1-13, lateral teeth; 14, 15, intermediate teeth; 16-26, marginal 
teeth. 

6. Tropicorbis riisci (Dunker). Lares, Puerto Rico. 

50, center tooth; 1,. lateral tooth; 5, 6, intermediate teeth; 7-12, marginal teeth. 

7. Tropicorbis obstructus (Morelet). New Orleans, Louisiana. 

60, center tooth; 1-7, lateral teeth; 8, 9, intermediate teeth; 11-14, marginal teeth. 

8. Tropicorbis havane^isis (Pfeiffer). New Orleans, Louisiana. 

55, center tooth; 1, lateral tooth; 6-8, intermediate teeth; 10, 12, marginal teeth. 

9. Gyraulus albus (Midler). Near Warsaw, Poland. 

60, center tooth; 1, 5, 8, lateral teeth; 10. intermediate tooth; 12. 13, marginal 
teeth. 







lUustratiojhs of the Anatomy and of Shells 373 








52 1 




60 1 










6 8 II 12 13 '■* 













gA<^^ 







^ 



V M 






14 ^ 15 









^^K < 





20 22 





PLATE 68 



374 The Molluscan Family Plariorbidae 



PLATE 69 

Radulae of Planorbidae 

See remarks on plate 53. Lines near figs. 1 to 5 indicate 25 microns in 
length; lines near figs. 6 to 9 indicate 10 microns in length. 

1. Gyraulus hirsutus (Govild). Lake Nipissing, Ontario, Canada. 

50, center tooth; 1, lateral tooth; 9, 11, intermediate teeth; 12-16, marginal teeth. 

2. Gyraulus deflectus obliquus (DeKay). Taylor Lake, Quebec, Canada. 

60, center tooth; 1, lateral tooth; 9-11, intermediate teeth; 13-18, marginal teeth. 

3. Gyraulus parvus (Say). Winnebago Lake, near Oshkosh, Wisconsin. 

55, center tooth; 1, 5, lateral teeth; 6, intermediate tooth; 7-10, marginal teeth. 

4. Gyraulus similaris (F. C. Baker). Tolland, Colorado. 

60, center tooth; 1, 6, lateral teeth; 8, 10. intermediate teeth; 13, 15, marginal 
teeth. 

5. Gyraulus vermicularis (Gould). Near San Francisco, California. 

50, center tooth; 1-6, lateral teeth; 7-10, intermediate teeth; 11, marginal tooth. 

6. Armiger imbricatus (Miiller). Michigan. 

55. center tooth; 1-6, lateral teeth; 8, 10, intermediate teeth; 12, 13, marginal 
teeth. 

7. Segmentina nitida (Miiller). Near War.saw, Poland. 

60, center tooth; 1-8, lateral teeth; 13-16, marginal teeth. 

8. Polypylis calathus (Benson). North Shan State, Burma. 

50, center tooth; 1-8, lateral teeth; 13-18, marginal teeth. 

9. Intha capitis Annandale. North Shan State, Burma. 

60, center tooth; 1-8, lateral teeth; 11, 12, marginal teeth. 



Ulustrations of the Anatomy and of Shells 375 




50 








2 60 1 




55 1 









n *- 






n 13 









12 15 









60 1 






5 50 1 




6 55 1 











10 11 





10 12 



Ts 




PLATE 69 



376 The Molluscan Family Planorbidae 



PLATE 70 

Animals of Planorbidae 

1. Hclisoma campanidatum (Say). Canadian specimen. View as seen crawling up side 

of aquarium jar. 

2. Helisoma scalare (Jay). March 13. Twelve hours out of egg. 

3. Helisoma scalare (Jay). Lake Butler, Florida. Adult with shell 10 mm. long. Drawn 

from aquarium specimen. 

4. Tropicorbis havanensis (Pfeiffer). New Orleans, Louisiana. Drawn from aquarium 

specimen. Shows pigmentation of mantle through shell. 

5. Gyraulus hirsutiis (Gould). Halfmoon Pond, near Alton Bay, Lake Winnipesau- 

kee. New Hampshire. Head and tentacles of crawling animal. 

6. Helisoma trivolvis (Sa.y). Oneida Lake, New York. Young Animal. 

7. Hclisoma trivolvis macrostomum (Whiteaves). Near Bayfield, Wisconsin. Side 

view of crawling animal with parts indicated. 

8. Hclisoma trivolvis jallax (Haldeman). Cambridge, Massachusetts. Animal crawl- 

ing up side of aquarium jar. 

9. Menetus dilatatus (Gould). Unionville, Connecticut. Animal crawling on stick in 

aquarium jar. Side view. 

10. Menetus dilatatus (Gould). Unionville, Connecticut. Top view of animal. 

11. Planorbula jeriksii (H. F. Carpenter). From pool near Lake Wentworth, New 

Hampshire. Animal crawling on bottom of aquarium jar. 

12. Helisoma subcrcuatum (P. P. Carpenter). Buccal sac with parts indicated. 

13. Gyraulus albus (Miiller). Buccal .sac. The outline of the radula is shown in the 

radular sac and the buccal sac. 

Lme near figure indicates 1 mm. in length 



Illustrations of the Anatomy and of Shells 377 




PLATE 70 



378 The Molluscan Family Planorbidae 



PLATE 71 

Isidora and Afroplanorbis 

1-6. Isidora globosa (Morelet). Copied from Connolly, Trans. Royal Soc. South 
Africa, XII, plate 8. 

1. Posterior end of penis (verge) with its sheath split open, showing the junction 

of the vas deferens with the penis (verge). Fig. 11. X 11. 

2. Alimentary canal and salivary glands seen from above. Fig. 12. X 6. 

3. Reproductive organs (genitalia). Fig. 14. X 5. 

4. Animal without its shell, seen from the left side. Fig. 13. X 3. 

5. Pulmonary orifice, with the folded branchial tube, anus, etc., on the right of it. 

Fig. 8. X 5. 

6. Posterior end of penis (vergic sac) showing penis papilla, this specimen ex- 

hibiting a different condition from that seen in fig. 1. Fig. 15. X 12. 

7-9. Planorbis pfeiffcri Krauss {^= Ajroplonorbif< pjeifjeri (Krauss)). Copied from 
Connolly, as noted above, plate 8. 

7. Lobes beneath the pulmonary orifice, seen from above. Fig. 17. X 8. Includes 

pseudobranch and rectum. 

8. Buccal mass, salivary glands, oesophagus, stomach, caecum, and first loop of 

intestine. Fig. 19. X 6. 

9. Reproductive organs (genitalia). Fig. 18. X 8. 

lQ-\2. Planorbis adowensis Bourg. (== Afroplanorbis adoweyisis (Bourg.)). Copied 
from Pilsbry, Proc. Acad. Nat. Sci. Phil., LXXXVI, p. 53. 

10. Genitalia showing spermatheca, prostate, uterus, etc. Fig. G. 

11. Male organ (penial complex) showing preputium and verge. Fig. F. 

12. Preputium cut open to show pilasters and end of verge, the verge indicated by 

dotted lines, u. s. upper sac (vergic .sac). Fig. H. 

Figures are great Iv enlarged 



Illustrations of the Anatomy and of Shells 379 




380 The Molluscan Family Planorbidae 



PLATE 72 

Acrorbis petricola Odhner 

Copied from Odhner's paper in Arkiv. for Zoologi, Band 29B, Xo. 14, 
two plates redviced to one plate in this volume. 

1-3. Acrorbis petricola Odhner. Shell from below, front view, and from above. 

4. Radula, one-half row on left side. X 1000. 

5. Animal removed from shell to show organization, from above. 

6. Head and foot of animal, fore view. 

7. Buccal sac. 

8. Digestive system, from above. 

9. Penial complex. 

10. Portion of genitalia. 

Description of symbols used on this plate: a, flagellum (anhangsdrlise) ; 
b, spermatheca (bursa copulatrix) ; c, caecum, a blind sac; d, intestine; 
f, tentacle; g, ganglia in nerve collar; go, ovotestis (gonad); h, heart in 
pericardium; j, jaw; k, pseudobranch (kiemen falte) ; I, liver; m, stomach; 
n, kidney (niere) ; o, oesophagus; od, oviduct (in the figure this refers to 
the ovisperm duct) ; p, prostate; ph, buccal sac; ps, preputium (penissack, 
here including the whole penial complex, preputium and vergic sac) ; 
r, rectum; rp, penial retractors; s, salivary glands (speichel driisen) ; 
t, radula sac (radula tasche) ; u, uterus; v, vas deferens. 



Illustrations of the Anatomy and of Shells 



381 




1 mm 2 



'®(^ 





O V 




10 



PLATE 72 



382 The MoUuscan Family Planorbidae 



PLATE 73 

* Indoplanorbis exustus (Deshayes) 

Genitalia cojiied from Larambergiie, 1939b, p. 288 

1. General view of genitalia (in French works the figures of both the animal and the 

shell are in reverse as compared with the position of American figures). 

2. Penial complex (appareil copulateur) with vergic sac cut open to show length and 

nature of verge. 

3. Transverse section of vas deferens (canal deferent). 

Explanation of symbols used on the plates: Al, albumen gland; Bf, 
buccal sac; C, junction of preputium with vergic sac (col); C '^ , ovi- 
sperm duct (canal hermaphrodite) ; Cd, vas deferens (canal deferent) ; 
G, preputium (gaine) ; G ^, ovotestis (glande hermaphrodite); Gu, 
nidamental gland (glande uterines) ; Od, oviduct; P, pilasters (piliers 
musculaires) ; Pc, spermatheca (poche copulatrice) ; Pe, verge (tube 
penial); Pp, vergic sac (poche du penis); Pr, prostate; R, retractor 
muscle (muscle fetracteur) ; compare the insertions of this figure with 
the figures on plate 22 of this work; Sp, sperm duct (spermiducte) ; 
Ut, uterus; Va, vagina. 

Vertical line indicates measurements in millimeters; horizontal line 
in microns. 



Illustrations of the Anatomy and of Shells 



383 




PLATE 73 



384 The MoUuscan Family Planorhidae 



PLATE 74 

Indoplanorbis exiistus (Deshayes) 
Genitalia copied from Larambergue, 1939b, p. 293 

6. Indi\'idual with verge and preputium protruded from male genital opening, the 

latter cut open to show portion of verge not everted. 

7. Two individuals of Indoplanorbis in coitus showing the extension of the penial 

complex from the body of the animal acting as male. Specimens anesthetized. 

8. Schematic figure of penial complex retracted within the body of the animal. 
9 Schematic figure of penial complex everted during copulation. 

Explanation of symbols on the plate: Cd, vas deferens; G, prejiutium 
(gaine) ; Pe, verge (tube penial); Pp, vergic sac (poche du i)enis). 

Vertical line indicates size in millimeters 



Illustrations of the Anatomy and of Shells 385 

6 7 




PLATE 74 



386 The Molluscan Family Planorhidae 



PLATE 75 

Bulinus contortus (Michaud) 
Genitalia copied from Larambergue, 1939a, p. 93 

4. General dissection of genitalia and fore part of body. 

5. Penial complex cut open to show characteristics. 

6. Carrefour of the genitalia. 

Explanation of symbols on the plate: A, atrium; Al, albumen gland; 
Bb, buccal sac; C, junction of preputium with vergic sac (col); C '^ , 
ovisperm duct (canal hermaphrodite); C Al, duct of albumen gland; 
Cd, vas deferens (canal deferent); G, preputium (gaine) ; G ^, ovo- 
testis (glande hermaphrodite); Od, oviduct; P, pilasters (piliers mus- 
culaires) ; Pc, spermatheca (poche copulatrice) ; Pe, verge (penis); Pp, 
vergic sac (poche du penis); Pr, prostate; R, retractor muscle; Sp, sperm 
duct; Ut, uterus; Va, vagina. 

Vertical line indicates size in millimeters 



Illustrations of the Anatomy and of Shells 



387 




.*«r;-' 



PLATE 75 



388 The Molluscan Family Planorbidae 



PLATE 76 

Shells of Planorbidae 

1. Planorbis krambergeri Halavats. Resultate d. Wissens. Erforsch. des Balatonsee, 

plate 3, figs. 3a, 3b, 3c. X6. 

2. Odontogyrorbis krambcrgeri (Halavats). Lorenthay, op. cit., Art. 3, plate 2, fig. 17. 

About X5. 

3. Costorbis strauchianits (Clessin). Conch. Cab., XVII, plate 31, fig. 5. X3. 

4. Segmentina nitida (Miiller). Apertural lamellae. Greatly enlarged. 

5. Polypylis hemisphacrida (Benson). Apertural lamellae. Greatly enlarged. 

6. Armiger crista (Linn.). Forbes and Hanley, Hist. Brit. Moll., IV, plate 126, figs. 

6, 7. About X4. 

7. Tropicorbis obstnictus (Morelet). Lamellae on outer lij). Enlarged. 

8. Planorbula armigcra (Say). Lamellae on outer lip. Greatly enlarged. 

9. Planorbida icheatleyi (Lea). Lamellae on outer lip. Greatly enlarged. 

10. Drepanotrema cultratum (Orbigny). From Bolivar, Colombia. Penial complex. 

Pilsbry, 1934, fig. 6, E (after H. B. Baker); fl, flagellum; vd, vas deferens; pr, 
penial retractor, vide Pilsbry. 

11. Pompholopsis whitei Call. Amer. Geol., I, p. 147, figs. 5-7. 

12. Vorticifex tryoni (Meek). White, Proc. U.S. Nat. Mus., V, plate 5, figs. 5-7. 

13. Vorticijex binneyi (Meek). Op. cit., figs. 8, 9. 

Figures 11 to 13 are natural size 



Illustratiois of the Auatotny and of Shells 



389 







1 



4!^:;^ 



-"^mmS^ 








o 






11 



12 








10 



390 The Molluscan Family Pla7iorbidae 



PLATE 77 

Shells of Planorbidae 

1-3. Gyraulus albus (Miiller). Pond in jiark in Krolikarnia. a suburb of Warsaw, 
Poland. Baker coll., 3968. X4. 

4-6. Gyraulus parvus (Say). Blue Pond, Wheatland Center Road, Monroe Co., New- 
York. U.I., 41369. X4. 

7-9. Tropicorbis orbiculus (Morelet). Drift at falls, Valles, Mexico. U.I., 28525. X2. 

10-12. Tropicorbis pallidus (C.B.Adams). Kingston, Jamaica. U.I. , 40466. X4. 

13-15. Taphius andecolus (Orb.). Lake Titicaca, Peru. U.L, 40595. Xl^/.. 

16-18. Anisus leucostoinus (Millet). Small pond in Bielany Park, Warsaw, Poland. 
Baker coll., 3969. X4. 

19. Anisus vortex (Linn.). Stream in meadow in Jab-Tonna, 18 km. northeast of 
Warsaw, Poland. Baker coll., 3971. X2. 

20-22. Anisus spirorbis (Linn.). Pond at Scarborough, England. Baker coll., 1234. X4. 

23-25. Bathyomphalus contortus (Linn.). Drewnica, 4 km. northea.st of Warsaw, 
Poland. Baker coll., 3972. X4. 

26-28. Planorbis planorbis (Linn.). A pond 25 km. southeast of Warsaw, Poland. 
Baker coll., 3970. X2. 

29-31. Australorbis glabrotus (Say). San Juan, Puerto Rico. M.C.Z., 65218. XP/o. 



Illustrations of the Anatomy and of Shells 391 






13 




14 




15 



20 







^^&B 



4| 



16 




17 





19 




23 



24 







25 




10 




11 




12 



26 




27 



f 








29 



28 



21 




22 





"^ 



31 



PLATE 77 



392 The Molluscan Family Pla)iorbidae 



PLATE 78 

Shells of Planorbidae 

1,2. Tropicorbis mcJlcus (Lutz). Upper and under side of animal. From Lutz, 
fig. 5, a, c. 

3. Tropicorbis nigrilabris (Lutz). Animal from above. Lutz, fig. 4, c. 

4. Tropicorbis nigrilabris (Lutz). Animal from above, lighter in pigmentation than 

fig. 3. From Lutz, fig. 6, c, mislabeled Planorbis nigricans by Lutz. Figures 1-4 

from Mem. Inst. Oswaldo Cruz, vol. 10, plate 16. Figures greatly enlarged. 
5-7. Helicorbis U7nbilicalis (Benson). Figures 5, 6, Hongkong, China. Baker coll., 

2756; fig. 7, Canton, China. Baker coll., 2751. X3. 
8-10. Pingiella peipinensis (Ping and Yen). Peiping, China. Baker coll., 3975. X3. 
11-13. Drepanotrema lucidum (Pfr.). Laguna del Bili, Alacranes Mts., Cuba. M.C.Z., 

129991. X3. 
14-16. Drepanotrema hoffmani F. C. Baker. Isabela, Puerto Rico. Types. Baker coll., 

3976. X3. 
17-19. Drepanotrema cultration (Orb.). Painters Pond, Painters, Antigua. U.S.N. M., 

272282. X3. 
20,21. Parapholyx effusa (Lea). Sacramento River, California. Probably type lot. Lea 

coll., U.S.X.M., 121167. X3. 
22. Parapholyx effasa (Lea). Sacramento River, California. Lea coll., LT.S.N.M., 

121133. X3. 
2Z. Carinif ex neu'berryi {Leu). Canoe Creek, California. U.S.N .M., 56405. X3. 
24. Carinifex newberryi (Lea). Canoe Creek, California. Type. Lea coll., U.S.N.M., 

9256. X3. 

25-26. Carinifex newberryi minor Cooper. Clear Lake, California. Lea coll., U.S.N.M., 
121025. X3. 



Illustrations of the Anatomy and of Shells 



393 





ui>\^ 





11 




12 




13 



14 




15 



16 



394 The Molluscan Family Planorbidae 



PLATE 79 

Shells of Planorbidae 

1-3. Segmentina nitida (Miiller). Swamp on a meadow in Czerniakow, a suburb of 

Warsaw, Poland. Baker coll., 3972. X4. 
4-Q. Hip pe litis fontanus {Ijightioot)=^ cornplanat us (Linn.). Damsells Mill Pond, 

Painswich, West Strand, England. Baker coll., 1256. X6. 
7-9. Polypylis largiUiarti (Phil.) ^ hemisphaerula (Benson). Peiping, China. Baker 

coll., 5973. X4. 
10-12. Platytaphius heteropleurus (Pils. & Van.). Lake Titicaca, Peru. Baker coll., 

3974. X2. 
13-15. Mcnetus dilatatus (Gould). Wrights Dike, Duxbury, Massachusetts. Baker 

coll., 3978. X4. 
16-18. Drepanolrcma anatinum (Orb.). Figures 16, 17, Para, Brazil. U.S.N.M., 348535; 

fig. 18, Para, Brazil M.C.Z., 72832. X5. 
19-21. Promenetus exacuous (Say). Small brook west bank Caj^uga Lake, near 

Cayuga, New York. Baker coll., 1140. X4. 
22-24. Mcnetus opercidaris (Gould). San Francisco, California. U.S.N.M., 227303. X4. 
25-27. Planorbida armigera (Say). Thief River Falls, Minnesota. U.I., 27093. X4. 
28-30. Planorbida ivheatlcyi (Lea). Boligee, Alabama. Baker coll., 1140. X4. 
31,32. PerriniUa corddlcriann (Hannibal). Truckee Lake Beds, Nevada. Hill near Haw- 
thorne, on Belmont Stage Road, Nevada. Hannibal, Proc. Mai. Soc, X, plate 

6, fig. 16, plate 8, fig. 34. About natural size. 
33-35. Indoplanorbis exustus (Desh.). Figures 33, 34, Bombay, India. Baker coll., 

1231; fig. 35, Calcutta, Lidia, Baker coll., 2229. Xl%. 



Illustrations of the Anatoiny and of Shells 395 



10 







13 



€1 

14 



15 




25 




26 




27 




16 




17 




18 




28 




29 




30 




19 




20 



21 




31 



32 




11 





12 



22 




23 



^BP^ Bp^ 



24 




33 





34 




35 



PLATE 79 



396 The MoUuscan Family Planorbidae 



PLATE 80 

Shells of Planorbidae 

1-3. Helisotna anceps (Menke) = Planorbis bicarinatus Sowb. and P. bicarinatus Say. 

From Delaware River II/2 miles above Plum Point, New Jersey. Like Say's 

figures. U.L, Z25738. X2. 
4-6. Helisoma anceps (Menke). South Street Brook, Auburn, New York. Strongly 

carinated form. U.L, Z25934. X2. 
7-8. Helisoma scalare (Jay). Everglades, head of Miami River, Dade Co., Florida. 

Baker coll., 237L X2. 
9. Helisoma duryi seminole Pilsbry. Lake Eustis, Florida. Physoid shell. Baker 

coll., 3977. X2. 
11-12. Helisoma duryi nurmale Pilsbry. Lake Pinsett, Florida. Typically planorboid 

shell. U.L, 41489. XIYj. 
13-15. Helisoma trivolvis (Say). Braddocks Bay, near Rochester, New York. Lake 

Ontario. U.L, 29789. XlV->. 
16-18. Helisoma campanulatum (Say). Thousand Island Park, St. Lawrence River, 

New York. U.L, 27112. Xli/1'. 
19-21. Helisoma multivolvis (Case). Howe Lake, Marciuette Co.. Michigan. Baker 

coll., 1962. X2. 
22-24. Planorbarius corneus (Linn.). Rhone River, France. U.L, 25740. Xli/2. 



IUustratio)is of the AiiatoDiy and of Shells 



397 




398 The Molluscan Family Planorbidae 



PLATE 81 

Shells of Planorbidae 

1. Poecilospira trochiformis (Stahl). Steinheiin, Germany. Showing extreme range 

of variation from short, flattened spire to long, conical spire. M.C.Z. X2. 

2. Ajroplnnorbis adoivensis (Bourg.). Belgian Congo, Africa. Pilsbry and Bequaert, 

Bull. Amer. Mus. N.H., LIII, fig. 4, p. 118. Xfi/^. 

3. Afroplanorbis sudanicus (Martens). Bahr-el-Ghazal, Africa. U.S.N. M., 215381. 

Pilsbry and Bequaert, op. cit., fig. 7, p. 122. Xli/4. 

4. Biomphalaria smithi Preston. Upper figures, specimen from Kabare, Lake Edward, 

Africa; lower figures, paratypes from Lake Edward. Pilsbry and Bequaert, op. 
cit., fig. 6, p. 121. Xli^. 

5. Paraplanorbis condoni (Hanna). Vicinity of Warner Lake, eastern Oregon. Pliocene 

period. Hanna, Univ. Oregon Pub., I, No. 12, plate 1, figs. 1-3. About X7. 

6. Planorhijex vanvlecki (Arnold). North dome Kettleman Hills, King Co., Cali- 

fornia. Pliocene. PiLsbry, Proc. Acad. Nat. Sci. Phil., 86, plate 21, fig. 9, a, b, c. 
Reduced one-half from Pilsbry "s figure. Line indicates 1 mm. 

7. Choanomphalus inaacki Ger.stfeldt. Crosse and Fischer, Jour, de Conch., XXVH, 

plate 4, fig. 9. 

8. Choanomphnlus valvatoidcs Dybowski. Op. cit.. plate 4, fig. 8. 

9. Choanomphalus schrenckii Dybowski. Op. cit., plate 4, fig. 10. Line near figures 

8-10 indicates natural size. 

10. Anisopsis calculus (Sandberger) . Land und Siiss.-Conch. Vorwelt, taf. 1, figs. 7, 7a. 

(stark vergrossert). 

11. Anisopsis loryi (Coquand). Op. cit., taf. 1, figs. 28, 28a, 28b. 



Illustrations of the Anatomy and of Shells 



399 




m^ 



28* ^ 



26^ 



10 



11 



PLATE 81 



400 The Molluscan Family Planorhidae 



PLATE 82 

Shells of Planorbidae 

1,2. Helisoma ancejhs (Menke). Ashhmd, Virginia. Resembling Menke's figure. B999. 

3-5. Helisoma anceps (Menke). Below dam at Lake Junalaska, North Carolina. B1819. 

6-8. Helisoma anceps (Menke). Long Lake, Alpena, Michigan. Resembling Rackett's 
figm'e of Helix angulata. BIOOL 

9-n. Helisoma anceps (Menke). Spring Grove, Dove Co., Alabama. Walker coll. Re- 
sembling Conrad's Planorbis antrosa. U.M., 6740L 

12-15. Helisoma anceps (Menke). Potomac River, Fort Washington, Maryland. 14, re- 
sembling unicarinatum ; 15, resembling sayi. U.S.N.M., 364718. 

16, 17. Helisoma anceps (Menke). Blue Creek, Coeur d'Alene Mts., Idaho. U.M., 81780. 

18,19. Helisoma anceps (Menke). Portland, Oregon. Hemphill coll. C.A.S., 6875. 

20-22. Helisoma anceps striatum (F. C. Baker). Bay View, Milwaukee, Wiscon.^in. 
From marl bed. B2851. 

23-25. Helisoma anceps shellense F. C. Baker. Shell Lake, Washburn Co., Wisconsin. 
23, paratype, U.I., Z19354; 24-25, type locality, U.I., Z13474. 

26. Helisoma anceps (Menke). Portland, Oregon. U.C.M., 23143. 

27-29. Helisoma anceps niinnesotoise (F. C. Baker). Frontenac, Minnesota. Types. 
B1002. 

30. Helisoma anceps (Menke). Priests Lake, Bonnar Co., Idaho. U.M., 81798. 

31. Helisoma anceps corrugatum (Currier). Northern part of Minnesota. B985. 
32-34. Helisoma anceps sayi F. C. Baker. East Lake Okoboji, Iowa. Shimek coll., 

U.S.N.M., 476580. 

Figures are enlarged approximately two diameters 




lUustratious of the Auatomy and of Shells 401 

mm J^ ^m 

^W ^^^ ^F 








10 




•t 



^ 



11 



12 




13 



*? "^W^ 




14 



15 



16 



17 



C) 




18 



19 






20 





(• 



21 22 



23 



24 





(' 



/" 



25 






'«*■ 



^ 



J 



26 



•.«>, 



27 



28 



29 







30 






31 



32 33 

PLATE 82 



34 



402 The Molluscan Family Plauorbidae 



PLATE 83 

Shells of Planorbidae 

1-3. Helisoma anceps sayi F. C. Baker. Tomahawk Lake, Oneida Co., Wisconsin. 

Type locality. U.I., Z25736. 
4-6. Helisoma anceps sayi F. C. Baker. West Lake Okoboji, Iowa. Shimek coll. Vary- 
ing toward anceps. U.S.N.M., 475945. 
7-9. Helisoma anceps unicarinatum (Haldeman). Plum Point, Delaware River, above 

Riverton, New Jersey. TJ.L, Z25938. 
10-12. Helisoma anceps unicarinatum (Hald.). Cherokee River, Little River Station, 

Alabama. U.I., Z41055. 
13-15. Helisoma anceps unicarinatum (Hald.). Blackstonc River, above Courtland, 

West Virginia. Figure 13 resembles Haldeman's angisiomum. LT.S.N.M., 109888. 
16-18. Helisoma anceps politum F. C. Baker. Honeywell Creek, Carleton Co., 

Ontario, Canada. F. R. Latchford coll. Holotype, fig. 16; paratypes, figs. 17, 

18. U.S.N.M., 367426. 
19-22. Helisoma anceps bartschi F. C. Baker. Brook at Great Falls, Virginia. Holotype, 

fig. 19; paratypes, figs. 20-22. U.S.N .M., 227858. 
23-25. Helisoma anceps (Menke). Variety? Mouth of Yaqui River, Northwest Mexico. 

LT.S.N.M., 53677. 
26. Helisoma anceps (Menke). Variety? Potomac River. U.S.N.M., 364718. 
27-29. Helisoma anceps aroostookcnse (Pilsbiy). Woodland, Aroostook Co., Maine. 

Type locality. U.I., Z21015. 

Figures are enlarged approximately two diameters 



Illustrations of the Anatomy and of Shells 403 






10 








11 



12 



13 



14 




W 4^1 ^^ 



'"^lAm- jm 




15 



16 



17 



18 




19 





( 



20 




21 



22 




^% 



/ 



23 



25 




24 



26 



f ^^ 



27 



28 
PLATE 83 




29 



404 The MoUuscan Family Plauorbidae 



PLATE 84 

Shells of Plauorbidae 

1. Helisoma anceps (Menke). Immature shell. XSVj. 

2. Helisoma anceps percarinatum (Walker). Immature shell. XZYz- 

3. Helisoma anceps portagense (F. C. Baker). Immature shell. XS^/^. 

4. Helisoma anceps royalense (Walker). Immature shell. XS^/^. 

5. Helisoma anceps sayi F. C. Baker. Immature shell. XS^/^. 

6-8. Helisoma anceps jordanense (Winslow). Lake Charlevoix, NE of Jordan, Charle- 
voix Co., Michigan. Topotypes. U.M., 61589. 
9. Helisoma anceps royalense (Walker). Isle Royale, Michigan. Cotype. B. Walker. 

B995. 
10-12. Helisoma anceps rushi F. C. Baker. Toad Island, Georgian Bay, Ontario. 

lOholotype; 11-12 paratypes. U.I., Z25239. 
13,14. HeUsoma rmceps royalense (Walker). St. Joseph Lake, Ontario. U.I., Z30853. 
15-17. Helisoma anceps royalense (Walker). Bamiji Lake, Ontario. U.I., Z30844. 
18-20. Helisoma eucosmius (Bartsch). Types. Bull. U.S.N.M., 33, plate 57, figs. 1-3. 

X4. 
21. Helisoma eucosmius (Bartsch). Greenfield Pond, North Carolina. Paratype. 

U.S.N.M., 193890. XSV-i- 
22-24. HeUsoma eucosmius vauyhani (Bartsch). Types. Bull. U.S.N.M., 33, plate 57, 

figs. 4-6. X4. 
25. Helisoma eucosmius vaughani (Bartsch). Burke's Place, Louisiana. Paratype. 

U.S.N.M., 125719. XSi;.. 
26-28. Helisoma anceps idahoense F. C. Baker. Pend (Jreille River, Sand Point, 

Idaho. Holotype. B1863. 

All figures are enlarged about twice excepting those otherwise listed 



fllusf rat ions of the Anatomy and of Shells 



405 








Y.-- ^ 







406 The Molluscan Family Planorhidae 



PLATE 85 

Shells of Planorbidae 

1-3. Helisoma anceps porlagenac (F. C. Baker). Portage Lake, Aroostook Co., Maine. 

Type locality. B988. 
4. Helisoma anceps portagense (F. C. Baker). Meach Lake, Quebec, Canada. B3686. 
5-7. Helisoma anceps latchfordi (Pilsbry). Meach Lake, Quebec, Canada. Type locality. 

Collected by Latchford. U.I., Z37203. 
8-10. Helisoma anceps percarinatum (Walker). Crystal Lake, Benzie Co., Michigan. 

Type locality. B986. 
11-13. Helisoma anceps percarhuititm (Walker). Douglas Lake, Michigan. 12 ridged 

shell. U.I., Z26276. 
14-16. Helisoma anceps cahni F. C. Baker. Big Muskallonge Lake, Vilas Co., Wis- 
consin. Types. U.I., Z21124. 
17-19. Helisoma trivolvis (Say). Immature shells. X3. 
20-24. Helisoma trivolvis (Say). Showing regular increa.se in growth of shell. LT.L, 

Z29134. 
25-29. Helisoma trivolvis (Say). Braddock's Bay, near Rochester, New York. U.L, 

Z29789. 
30. Helisoma trivolvis (Say). Elmira, Chemung Co., New York. U.L, Z34976. 

All figures excepting 17-19 are enlarged about 1% diameters 



Illustrations of the Anatomy and of Shells 



407 




) 




13 



t 



17 



18 






23 



24 



25 



26 




408 The Molluscan Family Plaiwrbidae 



PLATE 86 

Shells of Planorbidae 

I. Hclisoma trivolvis (Say). Indian River, Cheboygan Co.. Michigan. (^ Planorhis. 

megastoma DeKay.) U.I., Z32472. 
2.4. Heliaoma trivolvis (Say). Salt Fork, near Urbana, Chaniiuugn Co., Illinois. 

{ =^ Planurbis psiudotrivolvis F. C. Baker. 2, paratype; 4, holotype). U.I., 

Z 11292. 
3. Hclisoma trivolvis (Say). Salt Fork, near Urbana, Illinois. {^= Planorbis pseudo- 

trivolvis F. C. Baker. Type locality.) B930. 
5-8. Helisoma trivolvis lentum (Say). New Orleans, Louisiana. Type locality. \j.l., 

Z30538. 
9,10,1^- ficlisotna trivolvis intcrtextum (Sowerby). Manatee Rivor, Florida. U.I., 

Z32367. 

II, 12, 15. Hclisoma trivolvis intcrtextum (Sowb.). Shoal Creek, Alabama. U.I.. Z32365. 
14. Hclisoma trivolvis intertcxtum (Sowb.). Manatee River, Florida. B1085. 

16. Hclisoma trivolvis chautauquensc F. C. Baker. Chautauciiia Assembly, Chautau- 

ciua Lake, New York. Type locality. U.I., Z27842. 

17. Hclisoma trivolvis chautaucptoisc F. C. Baker. Chavitauqua Lake, New York. 

Holotype. U.L, Z23780. 

18. 19. Helisoma trivolvis chautauqucnse F. C. Baker. Chautauqua Lake, New York. 

Paratypes. U.L, Z23780. 

20. Hclisoma trivolvis (Say). Enlargement of whorls on base. B3914. X7. 

21. Hclisoma trivolvis (Say). {^ Planorbis pseudotrivolvis F. C. Baker). Enlargement 

of whorls on base. B3915. X7. 

22. Hclisoma trivolvis lentum (Say). Enlargement of whorls on base. B3916. X7. 

23. Helisoma trivolvis intcrtextum (Sowb.). F.nlargement of whorls on base. B3917. X7. 

All figures, excepting those indicated otherwise, are 
enlarged about I73 diameters 



Illustrations oj the Anatomy and of Shells 



409 




410 The MoUuscan Family Plmiorhidae 



PLATE 87 

Shells of Planorbidae 

1-4. HeUsoma trivoJvis fallax (Haldeman). Milton Mills, Milton, Massachusetts. U.I., 

Z41108. 
5-7. HcUsotna trivolvis fallax (Haldeman). Green Lodge, Xeponset. Massachusetts. 

B904. 
8,9. Hclisoma trivolvis fallax (Haldeman). Fresh Pond, Cambridge, Massachusetts. 

U.S.N.M., 33657L 
10. Helisomn trivolvis fallax (Haldeman). Port Elizabeth, Maine. U.S.X.M., 26449. 
11-15. HeUsoma trivolvis marshnlli F. C. Baker. Washington, D.C. 13, holotype; 

11-12, paratypes; 14-15, immature. U.S.N .M., 124989. 
16. HeUsoma trivolvis marshalli F. C. Baker. New Jersey. LT.S.N.M., 504153. 
17-20. HeUsoma trivolvis holstonense F. C. Baker. Holston River, Smith Co., Virginia. 

17, holotype; 18-20, paratypes. U.I., Z41443. 

21. HeUsoma trivolvis lentum (Say). New Orleans, Louisiana. Immature. Aquarium 

specimen. B3918. 

22. Hclisoma trivolvis holstonense F. C. Baker. Holston River, Virginia. Immature. 

U.I., Z41444. 
23,24. HeUsoma trivolvis holstonense F. C. Baker. Holston River, Virginia. Variation 
in color. U.I., Z41444. 

All figiu'es are enlarged about two diameters 



IUustratio)hs of the Aiuitony and of Shells 411 














r\ 





10 



11 



12 



13 






14 



15 




16 



17 





^ 



18 



19 



20 



6i i» 



21 



22 







23 



24 



PLATE 87 



412 The Molluscan Family Planorhidae 



PLATP: 88 

Shells of Planorbidae 

1,2. Helisoma trivolvis trivolvis (Say). Presqiie Isle, Michigan. Transition form toward 

macrostomum. U.I., Z26268. 
3. Helisoma trivolvis trivolvis (Say). Winnebago Lake, near Oshkosh, Wisconsin. Large 

form, but typical. U.I., Z1279L 
4-6. Helisoma trivolvis macrostommn (Whiteave.s). Mile End Gate, near Montreal, 

Canada. National Museum of Canada. 4, lectotype, 3869; 5-6, paratypes, 

B3870. 
7. H rlisoma trivolvis macrostomum (Whiteaves). Bayfield, Wisconsin. In beach pool. 

U.I., Z13677a. 
8-10. Helisoma pilsbryi (F. C. Baker). Tomahawk Lake, Oneida County, Wisconsin. 

Type locality. B843. 
11-13. Helisoma pilsbryi injracarinatnm F. C. Baker. Rideau River, near Ottawa, 

Canada. B3715. 
14, 15. Helisoma pilsbryi infracarinatum F. C. Baker. Basswood River Rapids, Rainy 

River District, Ontario. 14, holotype, U.I., Z32361; 15, paratype, B2986. 
16. Helisoma pilsbryi infracarit^atum F. C. Baker. Basswood Lake, Ontario, Canada. 

U.I., Z41268. 

All figures enlarged about 1V> diameters 



lUustrations of the Auatomij and of Shells 413 




414 The Molluscan Family Plwwrhidae 



PLATE 89 

Shells of Planorbidae 

1-4. Helisoma trivolvis hntum (Say). Austin, Texas. Figure 3 varies toward hiter- 

textum. U.S.N.M., 252256. 
5,6. Helisoma trivolvis intertcxtum (Sowb.). Fort Smith, Arkansas. Variation toward 

lentum (fig. 6). U.S.N.M., 120965. 

7. Helisoma trivolvis intertextum (Sowb.). South CaroHna? Binney's fig. 179 of Pln- 

norbis glabratus (not of Say). U.S.N.M., 29219. 

8. Helisoma trivolvis intertextum (Sowb.). Leon, Texas. U.S.N .M., 28210. 

9,10. Helisoma trivolvis reticulatum (Dall) {^intertextum Say). Salt Lake, Hils- 
borough Co., Florida. Types. U.S.N.M., 75421. 

11. Helisoma truncatum (Miles). Saginaw Bay, Michigan. Type. Binney's fig. 202. 

U.S.N.M., 9010. 

12. Pknwrbis bellus Lea (^= Helisoma trivolvis lentum (Say) ). Type. Tennessee. Lea 

Coll., U.S.X.M., 121178. 
13-17. Helisoma kennicotti F. C. Baker. Lake Isle la Crosse, English River, Canada. 
15, holotype; 16, 17, paratypes; 13, 14, immature. U.S.N.M., 29231 (old 9272). 

18. Helisoma subcrenatum (Cpr.). Reservoir near Flowcree, Montana. B3792. 

19. Helisoma subcrenatum (Cpr.). Wainwright Park, Alberta. U.I., Z34689. 

20. Helisoma subcrenatum {C]n\). Fort Yukon, Alaska. U.S.N .M., 218908. 

21. Helisoma subcrenatum disjecturn (Cooper). Boise, Idaho. U.I., Z36335. 

22. Helisoma subcrenatum plexatum (Ing.). Sagnache, Colorado. U.S.N.M., 535328. 

23. Helisoma occidentale (Cooper). Klamath Falls, (3regon. U.S.N.M., 219750. 

24. Helisoma occidentale (Cooper). Tule Lake, California. U.S.N.M., 160839a. 

25. Helisoma ammon (Gould). Daggett, California. U.S.N.M., 349083. 

26. Helisoma amnion (Gould). Spring Valley, San Mateo Co., California. U.M., 84105. 

27. Helisoma ammon (Gould). Clear Lake, California. U.M., 81743. 

28,29. Helisoma trivolvis (Say). Aquarium specimens raised by Dr. E. G. Berry. Note 
resemblance to Helisoma duryi seminole. B3796. 

Figures 18-29, immature. 

All figures are enlarged a trifle less than two diameters 



lUustratious of the Anatomy and of Shells 415 




PLATE 89 



416 The Molluscan Family Plauorbidae 



PLATE 90 

Shells of Planorbidae 

1-4. Helisoma (runcatum (Miles). Saginaw Bay, Michigan. Type locality. U.I., Z32515. 
5-8. Helisoma truncatuui (Miles). Spirit Lake, Iowa. U.S.N.M., 476566. 

9. Helisoma truncatum (Miles). Spirit Lake, Iowa. U.S.N.M., 505847. 

10. Heluoma truncatum (Miles). Sturgeon Bay, Door Co., Wisconsin. U.I., Z18455. 
11,12. Helisoma truncatum (Miles). Winnebago Lake, Wisconsin. U.I., Z12805. 
13-15. Helisoma subcrenatum disjectum (Cooper). Tuolumne, California. B1090. 
16-18. Helisoma subcrenatum disjectum (Coojier). Boise, Idaho. LT.L, Z36335. 
19-21. Helisoma subcrenatum horni (Tryon). Paul Lake, British Columbia. B3148. 
22-24. Helisoma subcrenatum variety? Quamichan Lake, British Cohmibia. B1973. 

All figures are enlarged a little less than two diameters 



Illustratio)is of the Anatonnj and of Shells 417 












/ 




y. 



c^^^j^ 





10 



11 



12 




13 




V 



^ 



16 



19 



14 




( 



17 




20 



15 




22 




21 




JjS 



418 The Molluscan Family Planorbidae 



PLATE 91 

Shells of Planorbidae 

1-4. Helisoma winslowi (F. C. Baker). Little Arbor Vitae Lake, Vilas Co., Wisconsin. 

Paratypes. Figure 4, immature. X 31/1-. U.L, Z18637, Z19398. 
5. Helisoma pilsbryi (F. C. Baker). Chetek Lake, Barron Co., Wisconsin. B. 
6-8. Helisoma pilsbryi preblei F. C. Baker. Knee Lake, Manitoba. Figure 6, holotype; 

7-8, paratypes. U.S.N.M., 180279. 
9-12. Helisoma subcrenatum (Carpenter). Idaho. Shimek Coll., U.S.N.M., 504310. 

13. Helisoma subcrenatum (Cpr.). Third Vermilion Lake, below warm sulphur cave, 

Alberta. Pathologic specimen. U.S.N.M., 272105. 

14. Helisoma subcrenatum (Cpr.). Lake La Hoche, British Columbia. U.S.N.M., 43346. 

15. Helisoma subcrenatum (Cpr.). Locomotive Springs, Kelton, Utah. U.S.N.M., 308926. 
16.18,19. Helisoma subcrenatum variety? Utah Lake, 2 miles south of Lehi, Utah. 

B1894. 
17. Helisoma subcrenatum variety? Same locality as above. Variation toward subcre- 
natum. B1894. 

All figures, excepting 4, are enlarged about V/j diameters 



lUustrations of the Anatouiy and of Shells 419 






8 




11 



14 



17 




C^^« 



10 



:.^lU 



> 




12 





15 




/ 




18 

PLATE 91 



19 



420 The MoUuscan Family Plaiwrbidae 



PLATE 92 

Shells of Planorbidae 

1,2. Helisoma subcrenatum (Cpr.). Newton, Utah. B3046. 

3. Helisoma suhcrenatum (Cpr.). Stewart River, Yukon Dist., Alaska. U.S.N .M., 

180281. 

4. Helisoma subcrenatum (Cpr.). Cleary, Alaska. Fos.sil pits. U.S.N .M., 381941. 

5. Helisoma subcrenatum (Cpr.). Great Slave Lake. Kennicott Coll., U.S.N.M., 9275. 
6,7. Helisoma subcrenatum (Cpr.). Wainwright Park, Alberta. B3919. 

8-10. Helisoma subcrenatum (Cpr.). Fort Simpson, Mackenzie District, Canada. Kenni- 
cott Coll., U.S.N.M., 28378. 

11,12. Helisoma subcrenatum (Cpr.). Creek one mile west of Devon, Montana. Im- 
matm-e. B3793. 

13-15. Helisoma subcrenatum horni (Tryon). Fort Yukon, Alaska. U.S.N.M., 218908. 

16. Helisoma subcrenatum horni (Tryon). Dall Ri\er, Alaska. Vaiying toward sub- 
crenatum. U.S.N.M., 180280. 

17-22. Helisoma subcrenatum plexatum (IngersoU). St. Mary Lake, Mineral Co., Colo- 
rado. Figure 17, lectotype, U.S.N .M., 420210; figs. 18-22, paratypes. U.S.N .M., 
125130. 

23. Helisoma subcrenatum plexaium (Lig.). Sagnache, Colorado. Lnmature. L^.S.N.M., 
535328. 

All figures are enlarged about IVj, diameters 



Illustrations of the Anatomy and of Shells 421 




422 The Molluscan Family Planorhidae 



PLATE 93 

Shells of Planorbidae 

1-3. Helisoma subcrenatum plexatum (Ing.). Great Falls. Montana. U.S.X.M., 183037. 

4. Helisoma occidentale (Cooper). Tule Lake, California. L'.S.X.M., 160S39a. 

5. Helisoma occidentale (Coojier). "Wa-^hington Territory.' Binney".s fig. 193. U.S.X.M.. 

9120. 

6. Helisoma occidentale (Cooper). Klamath Falls. Oregon. U.S.X.M.. 219750. 

7,8. Helisoma occidentale (Cooper). Upper Klamath Lake, .south boundary of reserva- 
tion, Oregon. L'.M., 62741. 

9.10. Helisoma occidentale (Cooper). Lower end Upi)er Klamath Lake, Oregon. 
B3246. 

11.12. Helisoma occidentale (Cooper). Slough at Wacos Bay, Klamath Lake, Oregon. 
B3069. 

13.14. Helisoma occidentcde (Cooper). Uiqier Klamath Lake. Oregon. B3011. 

15. Helisoma occidentale (Cooper). Upper Klamath Lake, south boundary of reserva- 

tion. U.M., 62741. 

16. Helisoma occidentale depression F. C. Baker. Lower Klamath Lake, Oregon. 

Holotype. B3239. 
17, 18. Helisovia occidentale depressum F. C. Baker. Lower Klamath Lake, Oregon. 

Paratypes. B3240. 
19,20. Helisoma binneyi (Tr3'on). Portland, Oregon. Stanford Univ., B3220. 
21,22. Helisoma binneyi (Tryon). Lake Whatcom, Washington. B853. 
23-26. Helisoma binneyi (Tryon). Holders Lake, Xanaimo, British Cohunbia. U.AL. 

81750. 

All figures are enlarged about l^-'> diameters 



lUustrations of the Aiiatomij and of Shells 



423 




424 The Molluscan Faniilij Plaiwrbidae 



PLATE 94 

Shells of Planorbidae 

1-5. Helisoma hinneyi randolphi F. C. Baker. Seattle, Washington. Figure 1, holotype; 

2-4, parat.ypes; 5, immature. U.S.X.M., 504360. 
6-8. Helisoma hinneyi randolphi F. C. Baker. Green Lake, Seattle, Washington. About 

half grown. U.S.N.M., 474779. 
9-11. Helisoma hinneyi (Tryon). Astoria, Oregon. B1888. 
12,13. Helisoma bi)tiieyi (Tryon). Portland, Oregon. Immature. LT.L, Z35295. 

14. Helisoma antmon (Gould). Spring Valley, San Mateo Co., California. Immature. 

U.M., 84105. 

15. Helisoma ammoii (Gould). Near Cerritos, Los Angeles Co., California. Immature. 

U.S.N.M., 174051. 

16. Helisoma hinneyi (Tryon). Astoria, Oregon. Back view of shell. U.I., Z18459. 

17. Helisoma ammon (Gould). Monterey, Monterey Co., California. Back view of 

•shell. U.M., 81746. 

18. Helisoma hinneyi (Tryon). Oregon. Tyi)e. Gould's figure of Planorhis corpnlentum 

Say, U.S. Ex. Exped., plate 8, fig. 130. U.S.X.M., 5530. 

19. Hilisotna hinneyi (Tryon). Columbia River, Oregon. Binney's fig. 191 of Planorhis 

corpulentum Say. U.S.N.M., 8119. 
20.21. Helisoma ammon (Gould). Hollister, San Benito Co., California. U.M., 81748. 
22-24. Helisoma ammon (Gould). Stockton, San Joachin Co., California. B3246. 
25,26. Helisoma a)nmon (Gould). San Joachin River, California. I'.M., 81749. 

27. Helisoma amnion (Gould). San Diego, California. TT.M., 35676. 

28. Helisoma am>no)i (Gould). Stockton, San Joachin Co., California. Immature. 

U.M., 81571. 

All figures are enlarged about II/2 diameters 



Illustrations of the Anatomy and of Shells 425 




426 The Molluscan Family Planorbidae 



PLATE 95 

Shells of Planorbidae 

1-5. Helisoma amnion (Gould). Mountain Lake near San Francisco, California. 

Immature form. B3288. 
6-9. Helisoma amnion (Gould). Clear Lake, California. Stages of growth. U.M., 81743. 
10,11. Helisoma avimon (Gould). Clear Lake, California. LT.M., 81752. 
12-14. Helisoma ammon (Gould). Watsonville, Santa Cruz Co., California. LT.M., 

81747. 

15. Helisoma ammon (Gould). Kern Lake, Tulare Co., California. Cooper Coll., 

B9124. 

16. Helisoma ammon (Gould). Point Happy, Indio, California. U.I., Z35624. 

17-19. Helisoma traskii (Lea). Bakersfield, Kern Co., California. Immature. U.M., 

81754. 
20,21. Helisoma traskii (Lea). Kern Lake, Tulare Co., California. Type of Lea, figured 

by Binney, 188. Lea Coll., U.S.N.M., 121000. 
22. Helisoma traskii (Lea). California? U.S.N.M., 47616. . 
23-25. Helisoma traskii (Lea). Bucna Vista Canal, draining Buena Vista Lake, which 

drained Kern Lake, California. More depres.sed than Lea's type. B3066. 

All figures are enlarged about P/i' diameters 



Illustrations oj the Anatomy and oj Shells 



427 



Obilito 



1 
6 












428 The Molluscan Family Planorbidae 



PLATE 96 

Shells of Planorbidae 

1-3. Helisoma oregoneiise (Tiyon). Pueblo Valley on boundary of Oregon, sixty miles 

west of east boundary. Type locality. B1096. 
4,5. Helisoma oregonense (Tryon). Nevada. Stearns Coll. U.M., 35679. 
6-8. Helisoma oregonense (Tryon). Sixteen miles northwest of Gerbach, Nevada. 

M.C.Z., 92410. 
9-12. Helisoma oregonense (Tryon). Variation. Tooele Co., Utah, in salt spring. 

B3920. 
13-17. Helisoma subcrenatum perdisjectum F. C. Baker. Yellowstone Lake, Wyoming. 

Figure 13, holotype; 14-17, paratypes. U.S.N.M., 30207a. 
18-22. Helisoma anceps anticostianum F. C. Baker. English Bay, Anticosti Island. 

Fig. 18, holotyi)e; 19-22, paratypes. M.C.Z., 48285. 
23-30. Helisoma anceps (Menke). Chevanus Pond, north of Knoxville, Tennessee. 

Figures 24, 25, 29, normal anceps; figs. 26, 27, 28. 30, the angistomus form of 

Haldeman; fig. 23, immature. M.C.Z., 46502. 
31-34. Helisoma magnificum (Pilsbry). Greenfield Pond, near Wilmington, North 

Carolina. Typo locality. Bartsch's figs. Proc. U. S. Nat. Mus., 33, plate 57, figs. 

7-9. U.S.N.M., 193321. 

Figures 1-30 are enlarged about two diameters; 
figs. 31-34 are about natural size. 



Illustrations of the Anatomy and of Shells 429 



te#^ 




""9 CP 



11 






12 




10 






13 



14 



15 



^ 




16 



17 




1- \ ^r3 

18 1^ 




21 



22 



23 



24 



25 



*( 



26 






27 



28 




'-•< ^.*- 



29 



30 




31 




.^ 




32 



\^ 



33 

PLATE 96 



M^V 



34 



430 The Molluscan Family Planorbidae 



PLATE 97 

Shells of Planorbidae 

1-4. Helisoma tenue (Philippi). Platpa near City of Mexico, Mexico. Tj'pe locality. 
U.S.N.M., 160175. 

5. Helisorna tenue (Philippi). Laguna de Tamos, near Tampico. Vera Cruz, Mexico. 

U.S.N.M., 467437. 

6. Helisoma tenue (Philippi). Toluca, Mexico. U.S.N .M., 185942. 

7,8. Helisoma tenue (Philippi). Lake Texcoco, near City of Mexico, Mexico. M.C.Z. 

9. Helisoma tenue (Philippi). Vera Cruz. Strebel Coll. U.S.N.M., 10585. 

10. Helisoma tenue (Philijipi). Sources of Rio Lerma, Valley of Toluca, Mexico. 

U.S.N.M., 467433. 

11. Helisoma tenue (Philippi). Orizaba, Mexico. U.S.X.M., 22009. 

12. Helisoma tenue bourcardi (C. and F.). City of Mexico, Mexico. U.S.N.M., 8506. 
13-17. Helisoma tenue bourcardi (C. and F.). City of Mexico, Mexico. U.S.N.M., 

26453. 
18-25. Helisoma tenue craggeratum (von Martens). Lake Patzcuaro, State of Michoa- 

can, Mexico. Type locality. U.S.N.M., 467462. 
26-28. Helisoma tennc applanatum (von Marten.s). Lanos River, Chichuachua, Mexico. 

U.S.N.M., 16252. 

All figures are enlarged about P/o diameters 



lUustratiotis of the Anatotny and of Shells 



431 




PLATE 97 



432 The Molluscan Family Planorhidae 



PLATE 98 

Shells of Planorbidae 

1. Helisoma tenue applanatam (von Martens). Orizaba, Mexico. Strebel Coll. 

U.S.N.M., 10538. 
2-6. Helisoma tenue applanatum (von Martens). Yaqui River, near Cimlad Obregon, 

Sonora, Mexico. U.S.N.M., 467429. 
7,8. Helisoma tenue applanatuni (von Martens). Mazatlan, Mexico. Lea Coll. 

U.S.N.M., 121192. 
9-13. Helisoma tenue sinuosum (Bonnet). Santa Cruz River, Tucson, Arizona. In 

stream bed. U.S.N.M., 130237. 
14-. Helisoma tenue sinuosum (Bonnet). Soroyta Creek, Sonora, Mexico. U.S.N. M., 

130229. 

15. Helisoma tenue sinuosum (Bonnet). Albuquerque, New Mexico. 5000 ft. altitude. 

U.S.N.M., 134552. 

16, 17. Helisoma tenue caUforniense F. C. Baker. Santa Cruz, California. U.S.N.M., 

47571. 
18. Helisoma tenue calijorniensc F. C. Baker. Santa Cruz, California. U.S.N. M., 47572. 
19-21. Helisoma tenue calijorniense F. C. Baker. Crystal Creek, San Jose, California. 

U.S.N.M., 32111. 

22. Helisoma tenue ealijorniensc F. C. Baker. Santa Cruz Mts., 4 miles from Los 
Gatos, California. U.S.N.M., 75437. 

23,24. Helisoma tenue calijorniense F. C. Baker. Guadeloupe Creek, San Jose, Cali- 
fornia. Paratypes. B3262. 

25. Helisoma tenue sinuosum (Bonnet). Rio Grande. El Paso, Texas. Immature. 

U.S.N.M., 130239. 

26. Helisoma tenue calijorniense F. C. Baker. Bixby, Los Angeles Co., California. 

Immature. B3227. 

Figures 25 and 26 show differences in spire whorls and 
sculpture of the two ^'arieties 

All figures are enlarged about V/^. diameters 



Illustrations of the Anatomy and of Shells 433 




434 The Molluscan Family Planorbidae 



PLATE 99 

Shells of Planorbidae 

1. Hclisoma ienue applanatutn (\on Martens). Near Vallecitos, Lower California. Im- 
mature. U.S.N.M., 162654. 

2,3. Hclifioma tome applanatum (von Martens). Yaqui River, near Ciudad Obregon, 
Mexico. Immature. U.S.N.M., 467429. 

4-8. Hvlixoma tenue sinuosiini (Bonnet). Santa Cruz River, Tucson, Arizona. Imma- 
ture. U.S.N.M., 130237. 

9,10. Hclisoma tenue sinuosum (Bonnet). Rio Grande, El Paso, Texas. Immature. 
U.S.N.M., 130239. 

11-15. Helisoma tenue calif orniense F. C. Baker. Bixby, Los Angeles Co., California. 
Immature. U.S.N.M., 174048. 

16-19. Hclisoma tenue strebclianum (F. and C). Penasco, 5 miles north of San Luis 
Potosi, Mexico. Immature. LT.S.N.M., 251815. 

20-24. Hclisoma caribacum guatcmalcnsc (Clessin). Reservoirs 4 miles north of 
Guatemala City, Guatemala. U.M., 83490. 

25. Hclisoma tenue strebelianum (F. and C). Tamaulipus, Mexico. LT.S.N.M., 109916. 

26. Hclisoma tenue strebelia7ium (F. and C). Coy River, San Luis Potosi, Mexico. 

B3921. 

27-30. Hclisoma tenue strcbelianuia (F. and C). Alta Mira, Tamaulijius, Mexico. 
U.S.N.M., 251807. 

31. Hclisoma caribacum (Orb.). Naranjo, (Juatemala. Varying toward Hclisoma cari- 
bacum guatcmalense. LT.M., 83487. 

32-36. Helisoma caribaeu}7i guatemalense (Clessin). Nicaragua. U.M., 83485. 

All figures are enlarged about 1^/4 diameters 



Illustrations oj the Anatomy and of Shells 435 




436 The Molluscan Family Plauorbidae 



PLATE 100 

Shells of Planorbidae 

1,2,5. Ilclisoma caribaeum (Orb.). Cuba. I'.M., 83491. 

3.4. Helisoma caribaeum (Orb.). Punta d? hi Junta, Cuba. U.S.X.M.. 11204. 

6-10. Helisoma caribaeum (Orb.). Panama. U.M., 83492. 

11-13. Helisoma caribaeum (Orb.). Somorrostro, Havana, Cuba. B3075. 

14-17. Helisoma caribaeum (Orb.). Vera Cruz, Mexico. U.S.X.M., 210882. 

18-20. Helisoma unjldii saluini (Tristram). Guatemala. U.S.X.M., 121023. 

21-24. Helisoma ivijidii (Tristram). San Carlos, Nicaragua. U.S.N. M., 354295. 

25-27. Helisoma unjldii (Tristram). Lake Olomega, San Salvador. U.S.N. M., 360392. 

28. Helisoma wyldii (Tristram). Lake Metapan, San Salvador. U.S.N.M., 360391. 

29,30. Helisoma wyldii (Tristram). Lake Guija, San Salvador. U.S.N.M., 360390. 

31. Helisoma lumens (Cpr.). Mazatlan, Mexico. U.S.N.M., 46967. 

32,33. Helisomn tumens (Cpr.). Mazatlan, Mexico. U.S.N. M., 47517. 

34-37. Helisoma tumens (Cpr.). Mazatlan. Mexico. B2284. 

All figures are enlarged about \y> diameters 



Illustrations of the Anatomy and of Shells 



437 




18 27 

PLATE 100 



438 The Molluscan Family Planorhidae 



PLATE 101 

Shells of Planorbidae 

1. Helisoma jovealc (Menke). Jamaica. U.S.N.M., 74762. 

2. Helisoma jovealc (Menke). Jamaica. U.S.N.M., 90479. 

3,4,6. Helisoma foveale (Menke). Kingston, Jamaica. U.S.N.M., 454058. 

5. Helisoma foveale (Menke). Kingston, Jamaica. U.S.N. M., 74762. 

7. Helisoma magnificum (Pilsbry). Young, bom in capti\-ity. Parent from type 

locality. U.S.N.M. 
8,9. Helisoma costaricense (Preston). Catalina, Guanacaste, Costa Rica. Cotype. 

B2132. 
10. Helisoma costaricense (Preston). Catalina, Guanacaste, Costa Rica. Figured type. 

U.S.N.M., 202522. 
11.12. Helisoma anceps idahoense F. C. Baker. Foot of Elbow or Lindbergh Lake, 

Mission Mts., Montana. M.C.Z. 

13. Helisoma subcremttum variety? Utah Lake, Utah. U.S.N.M., 29332. 

14. Helisoma suhcrcnatum. (Cpr.). Oregon. From Nuttall in Lea Coll. U.S.N.M., 

120986. 

15. Helisoma caribacum (Orb.). Cuba. To show rounded inner whorls. U.M., 83491. X6. 

16. Helisoma teniic applanatum (von Martens). To show flat inner whorls. U.S.N.M., 

10538. 

All figures, excepting 15 and 16, are enlarged about U/2 diameters 



Illustrations oj the Anatomy and of Shells 



439 




•■»*.. -.,^ 



M Ul^ 



15 



16 



PLATE 101 



440 The Molluscan Family Planorbidae 



PLATE 102 

Shells of Planorbidae 

1. Hdisoma tenue chapaleme (Pilsbry). Proc. Acad. Sci. Phil., 1920, i>. 193, fig. 1. En- 

larged. 

2. Hclisoma contrerasi (Pilsbiy). Proc. Acad. Sci. Phil., 1920, \k 193, fig. 2. Enlarged. 
3,4. Helisoma contrerasi (Pilsbry). Lake Chaiiala, near Guadalajara, Mexico. U.S.N.M., 

225863. 
5-10. Hclimma ten tie ehapalense (Pilsbry). Oaxaca, Mexico. U.S.N.M., 117952. 
11,12. Helisoma seal are (Jay). Caloosatchee Pliocene formation, Florida. B1106. 
13,14. Helisoma scalare (Jay). Lake Griffin, near Leesburg, Florida. B1438. 
15-18. Helisoma scalare (Jay). Head of Miami River, Everglades, Dade Co., Florida. 

B2969. 
19,20. Helisoma scalare (Jay). Everglades, Florida. B3002. 
21. Helisoma duryi seminole Pilsbry. Everglades, Florida. B2962. 
22,23. Helisoma duryi seminole Pilsbry. Sumter Co., Florida. B2965. 

All figures, excepting 1 and 2. are enlarged about two diameters 



Illustrations of the Anatomy and of Shells 441 





£ 





#^% 




442 The Molluscan Family Plauorbidae 



PLATE 103 

Shells of Planorbidae 

1,2. Helisoma duryi soninole Pilsbry. Everglades, Florida. B2962. 

3-5,8,9. Helisoma duryi scminole Pilsbry. Lake Eustis, Lake Co., Florida. Paratypes. 

B2960. 
6,7. Helisoma duryi semiiiole Pilsbry. Lake Eustis, Lake Co., Florida. U.L, Z32368. 
10, 11. Helisoma duryi seminole Pilsbry. Okechobee Lake, near More Haven, Florida. 

M.C.Z., 43311. 

12. Helisoma duryi seminole Pilsbry. Lake Apopka, Florida. M.C.Z., 71599. 

13. Helisoma duryi seminole Pilsbry. Lake Apopka, Florida. M.C.Z., 71598. 
14-18. Helisoma duryi semiiiole Pilsbry. Survey, Lee Co., Florida. M.C.Z., 68236. 
19. Helisoma duryi seminole Pilsbry. Sumter Co., Florida. U.L, Z32364. 

20-30. Helisoma duryi (Wetherby). Near West Palm Beach, Florida. M.C.Z., 82856. 
31. Helisoma duryi (Wetherby). Miami, Florida. L'.S.N.M.. 153412. 

These figures show the great variation in form of spire and shape of 
shell of the dnryi complex, especially the form seminole. 

All figures are enlarged about P/i; diameters 



Ilhisf rations of the Anatomy and of Shells 



443 



V 







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444 The Molluscau Family Planorbidae 



PLATE 104 

Shells of Planorbidae 

1-3. Heliscmici duryi (Wetherby). Kissimmee River, Florida. \'ariation toward variety 
normale. U.S.N.M., 168921. 

4-7. HcUsoma duryi (Wetherby). Near West Palm Beach, Palm Beach Co., Florida. 
Variation toward variety normale. M.C.Z., 45103. 

8-16. Helisoma duryi normale Pilsbry. One mile north of Oil well, Pinecrest, Ever- 
glades, Florida. U.I., Z34637. 

17. Helisoma duryi normale Pilsbry. Canal west of Boynton, Palm Beach Co., Florida. 
Malleated base. M.C.Z., 76659. 

18-22. Helisoma duryi normale Pilsbry. Magnolia, Florida. M.C.Z., 87505. 

All figures are enlarged about 1V> diameters 



lUustratioiis of the Anatomy and of Shells 445 







15 




(^ 





16 



10 






11 



17 



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r^ 



12 






18 






19 



13 





PLATE 104 



446 The Molluscan Family Plauorhidae 



PLATE 105 

Shells of Planorbidac 

1-3. Helisoma duryi nurtnale Pilsbry. Everglades 40 miles from Ft. Meyers, Florida. 

M.C.Z., 71020. 
4-8. Helisoma duryi intercalarc (Pil.^bry). East shore Lake Okeechobee, Palm Beach 

Co., Florida. M.C.Z. 
9. Helisoma duryi intercalarc (Pilsbry). Beecher Spring, Wakulhi, Wakullii Co., 

Florida. U.S.N.M., 153079. 
10.11. Helisoma duryi iuterccdare (Pilsbry). Lake Je.ssup, Florida. U.S.X.M., 167040. 
12,13. Helisoma duryi intercalarc form alternalum Pilsbry. Blue Creek, Lake Co., 

Florida. Type locality. M.C.Z., 83729. 
14-16. Helisoma duryi eudiscus Pilsbry. Head of Miami River, near Miami, Dade 

Co., Florida. Paratypes. B3074. 
17-19. Helisoma duryi eudiscus Pilsbry. Silver Springs, Marion Co., Florida. Varying 

toward intercalare. B3073. 
20-27. Helisoma duryi prcglabratum (Marshall). Canal, Palm Beach Co., Florida. Type 

locality. M.C.Z. , 46572. 

AH figures are enlarged about lY^ diameters 



Illustrations of the Anatomy and of Shells 447 




448 The Molluscan Family Plauorhidae 



PLATE 106 

Shells of Planorbidae 

1-3. Helisoma duryi seminole Pilsbiy. Florida. U.S.N.M., 99301. 

4. Helisoma connnti Dull. Calocsahatchee River. Florida. U.I., Z40570. 

5-7. Helisoma conanti Dall. Caloosahatchee River, Florida. B1107. 

8. Helisoma disstoni (Dall). Vero, St. Lucia Co., Florida. U.S.X.M., 331971. 

9-11. Helisoma species? Asecibo, Puerto Rico. U.S.X.M., 535394. 

12-15. Helisoma disstoni (Dall). Canal, Palm Beach Co., Florida. M.C.Z., 99182. 

16. Helisoma corpulentum midticostatum F. C. Baker. Lake Kahnipiminanikok, 

Ontario, Canada. Young. U.I., Z32628. 

17. Helisoma corpulentum (Say). Lac la Croix, Ontaria, Canada. Youno;. U.L, 

Z32626. 

18. Helisoma whiteavesi F. C. Baker. Lac des Mille Lacs, Ontario, Canada. Holotype. 

U.L, Z32311. 
19,20. Helisoma ivhiteavesi F. C. Baker. Lac des Mille Lacs, Ontario, Canada. Para- 
types. U.L, Z32312. 

21. Helisoma ivhiteavesi F. C. Baker. Lac des Mille Lacs, Ontario, Canada. Paratype, 

Immature. U.L, Z32313. 

22. Helisoma corpulentum (Say). Kettle Fall.'^, Rainy Ri\er District. Ontario, Canada. 

Began as a corpulentum and on last whorl changed form of shell toward that of 
multicostatuyn. U.S.N.M., 361737. 

All figures are enlarged about P,-'> diameters 



Illustrations of the Anatomy and of Shells 449 




€ 



^^ 




12 




15 




450 The MoUuscan Family Plauorbidae 



PLATE 107 

Shells of Planorbidae 

1-4. Hclisomo corpuloition (Say). Lac la Croix, Ontario. Canada. U.I., Z32296. 

5. Helisoma corpulent lun (Say). Rainy Lake, Ontario, Canada. A type locality. BUOl. 

6. Helisoma corpulentum (Say). Rabbit Point, west of Sabaskong Bay, Lake of the 

Woods, Canada. A type locality. Resembles Say's figure. U.L, Z41286. 

7. Helisoma cor]>uletdum (Say). Lac la Croix, Ontario, Canada. U.L, Z32626. 

8. Helisoma corpulentum vennilioncnse F. C. Baker. Vermilion Lake, St. Louis Co., 

Minnesota. Holotype. B3021. 
9,10. Helisoma coripulentum vermilionense F. C. Baker. Vermilion Lake, Minnesota. 
Paratypes. B3014. 

11. Helisovia corpulentuvi vermilionense F. C. Baker. Vermilion Lake, Minnesota. 

Paratype, immature. U.L, Z32518. 

12. Helisoma corpulenlum multicostatiim F. C. Baker. Lake Kahnipiminanikok, 

Ontario, Canada. Holotype. U.L, Z32308. 

13. Helisoma corpulenlum (Say). Lac la Croix, Ontario, Canada. Young. U.L, Z32626. 

14. Helisoma corpulentuni vermilionense F. C. Baker. Vermilion Lake, Minnesota. 

Young. U.L, Z32627. 

15. Helisoma whiteavesi F. C. Baker. Lac des Mille Lacs, Canada. Young. U.L, 

Z32312. 
16-18. Helisoma corpulentum multicostatum F. C. Baker. Kahnipiminanikok Lake, 
Ontario, Canada. Paratypes. U.L, Z32307. 

19. Helisoma corpulentum multicostatum F. C. Baker. Knife Lake, Minnesota. U.L, 

Z29828. 

20. Helisoma corpulentum multicostatum F. C. Baker. Bemidji Lake, Beltrami Co., 

Minnesota. U.L, Z32475. 

21. Helisoma corpulentum multicostatum F. C. Baker. Kahnipiminanikok Lake, On- 

tario, Canada. Lnmature. U.L, Z32628. 

All figures are enlarged about P/^ diameters 



niusf rations of the Anntomy and of Shellt 



451 




5 

r 



^W^^is^f^^ 



452 The Molluscan Family Plauorhidae 



PLATE 108 

Shells of Planorbidae 

1-6. Helhoma cainpanulatum (Say). Cayuga Lake, New York. Type locality. U.S.N. M., 

212700. 
7-9. Helkoma campanulatum (Say). North end Cayuga Lake, New York. Probable 

type locality. B1043. 
\0,n. Hdkoma campanulatum (Say). Ottawa, Ontario, Canada. U.S.N.M., 120985. 
12-14. Hdisoma campanulatum (Say). North end Canandaigua Lake, New York. 

B3859. 
15-17. Hdisoma campanulatum (Say). Crooked Lake, Odcn, Michigan. Variation in 

size. U.L, Z19877. 

18. Hdisoma campanulatum fcrrmi F. C. Baker. Marl Lake, Fair Grounds, Joliet, 

Will Co., IlHnois. Holotype. U.L, P1068a. 

19. Hdisoma campanulatum ferrissi F. C. Baker. Same locality as above. Paratype. 

U.L, Pl068b. 

20-25. Hdisoma campanulatum ferrissi F. C. Baker. Same locality as above. Para- 
types. U.L, P1068. 

26-28. Hdisoma campanulatum jcrrissi F. C. Baker. White Lake, Oakland Co., Michi- 
gan. U.L, Z20908. 

29-31. Hdisoma campanulatum ferrissi F. C. Baker. Literior Charity Lsland, Michigan. 
B3860. 

32-34. Hdisoma campanulatum ferrissi F. C. Baker. Lermond, Bonne Bay, Newfound- 
land. B3858. 

All figures are enlarged about two diameters 



Illustrations of the Anatomy and of Shells 



453 





% 






32 



33 

PLATE 108 



34 



454 The Molluscan Family Planorhidae 



PLATE 109 

Shells of Planorbidae 

1-6. Helisoma campanulatum (Say). Pine Island Lake, Kent Co., Michigan. Exagger- 
ated campanulate lip. B3922. 

7. Helisoma campanulatum wisconsinense (Winslow). Little Arbor Vitae Lake, Vilas 

Co., Wisconsin. Type locality. U.I.. Z18421. 

8. Helisoma campanulatum wisconsinense (Winslow). Tomahawk Lake, Wisconsin. 

B1718. 

9. Helisoma campanulatum wisconsinense (Winslow). Tomahawk Lake, Wiscon.sin. 

B1719. 
10,11. Helisoma cantpanulatum wisconsinense (Winslow). Tomahawk Lake, Wisconsin. 

B1725. 
12,13. Helisoma campanulatum wisconsinense (Winslow). Tomahawk Lake, Wisconsin. 

B3857. 
14. Helisoma campanulatum smithii (F. C. Baker). Douglas Lake, Michigan. Holo- 

type. B1054. 
15,16. Helisoma campanulatuui smithii (F. C. Baker). Douglas Lake, Michigan. Para- 
types. B1728. 
17-20. Helisoma campanulatum smithii (F. C. Baker). Douglas Lake, Michigan. Type 

locality. B3861. 
21. Helisoma campanulatum rideauense F. C. Baker. Rideau River, Ottawa, Canada. 

Holotype. U.S.N.M., 346627. 
22-24. Helisoma campanulatum rideauense F. C. Baker. Rideau River, Ottawa, 

Canada. Paratypes. U.S.N.M., 346627. 
25. Helisoma campanulatum smithii (F. C. Baker). Douglas Lake, Michigan. Small 

form. B1056. 
26-28. Helisoma midtirolvis (Case). Howe Lake, Marquette Co., Michigan. U.I.. 

Z23192. 
29. Helisoma multivolvis (Case). Howe Lake, Marquette Co., Michigan. U.S.N. M., 

272274. 

All figures are enlarged about iy> diameters 



niustrations of the Anatomy and of Shells 



26 



455 





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PLATE 109 



29 



456 The MoUuscan Family Planorhidae 



PLATE 110 

Shells of Planorbidac 

1-4. Helisoma cainpanulatum wiscon-'iinensc (Winslow). Tomahawk Lake, Wisconsin. 

1, 2. Immature. 3, 4, Small form. U.I., Z29858. 
5-7. Helisoma campanulatum near variety smithii (F. C. Baker). Douglas Lake, 

Michigan. U.I.. Z13957. 
8-10. Helisoma campanulatum smithii (F. C. Baker). Doughis Lake, Michigan. Small 

form. B1056. 

11. Helisoma campamilatum canadense F. C. Baker. Bamiji Lake, Ontario, Canada. 

Holotype. U.L, Z30721. 

12, 13. Helisoma campanulatum canadense F. C. Baker. Bamiji Lake, Ontario, Canada. 

Paratypes. U.L, Z30721. 
14. Helisoma campanulatum canadense F. C. Baker. Brent Lake, Ontario, Canada. 

U.L, Z41303. 
15-17. Helisoma campanulatum canadense F. C. Baker. Lake near Lake Mercutio, 

Ontario, Canada. Variation in size. LT.L, Z40064. 
18-20. Helisoma campanulatuin canadense F. C. Baker. Sturgeon Lake, Ontario, 

Canada. Variation in size. U.L, Z32331. 
21. Helisoma campanulatum pleistocenicum F. C. Baker. White Pond, Marlboro, New 

Jersey. Holotype. U.S.N.M., 121195. 
22-26. Helisoma campanulatum pleistocenicum F. C. Baker. AVhite Pond, Marlboro, 

New Jersey. Paratypes. U.S.N.M., 121195. 
27-35. Helisoma campanulatum collinsi F. C. Baker. Cameron Lake, Lake of the 

Woods, Canada. Variation in size. U.L, Z41297. 

All figures are enlarged about two diameters 



lUuslratnn,, oj the A„at,w,u and 0/ Sh.\h 



457 




cm 



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PLATE 110 




13 






18 



22 




27 




31 





35 



458 The Molluscan Family Planorhidae 



PLATE 111 

Shells of Planorbidae 

1-5. Hclisoma camptuiulatuin rudentis (Dall). Knee Lake, Manitoba, Canada. Para- 
types. U.S.N.M., 365574. 

6,7. Helisoma carnpanidalum michiganense F. C. Baker. Marl Lake, Roscommon Co., 
Michigan. 6, holotype, B1809; 7, paratype, B1809a. 

8,9. Helisoma cainpaitidatum michiganense F. C. Baker. Marl Lake, Roscommon 
Co., Michigan. U.S.N.M., 173102. 

10, 11. i/(7i.som« campauulatum ))iichiganeyise F. C. Baker. Marl Lake, Michigan. 
U.S.N.M., 173102. 

12,13. Helisoma campanulatinn dalli F. C. Baker. Anticosti Island, Canada. 12, holo- 
type; 13, paratype. U.S.N.M., 162724. 

14. Hclisoma campanulatum michiganense F. C. Baker. Marl Lake, Michigan. Ab- 
normal. U.S.N.M., 173102. 

15,16. Helisoma campanulatum dalli F. C. Baker. Anticosti Island, Canada. Para- 
types. U.S.N.M., 162724. 

17-19. Helisoma campanulatniii colUnsi F. C. Baker. Cameron Lake, Lake of the 
Woods, Ontario, Canada. 17, holotype; 18, 19, paratypes. U.I., Z41297. 

20. Helisoma campanulaUim collinsi F. C. Baker. Cameron Lake, Lake of the Woods, 
Canada. Paratype. A small specimen. U. I., Z41297. 

21,22. Helisoma catnpanulatum (Say). Crooked Lake, Emmet Co., Michigan. Young. 
B3868. X31/2. 

23-31. Helisoma scalare (Jay). Everglades, Florid;i. Marl bed 10-15 ft. under peat. 
Variation toward seminole form. LT.S.N.M., 348566. 

32. Hclisoma duryi seminole Pilsbry. Lake Apopka, Florida. Showing advanced lower 
part of aperture in contrast with the receding aperture of scalare (fig. 31). 
U.S.N.M., 566570. 

All figures, excepting 21 and 22, are enlarged about 1% diameters 



Illustrations oj the Anatutny and of Shells 459 




£b| 





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11 



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22 23 24 ^^^"^ 

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27 



28 



29 30 



PLATE 111 



31 32 



460 The MoUuscan Family Plauorhidae 



PLATE 112 

Shells of Planorbidae 

1-6. Helisoma duryi seminole Pilsbry. Lake Apopka, Florida. Range of variation. 
U.S.N.M., 506868. 

7,8. Helisoma duryi seminole PiLsbry. Lake Apopka. Florida. scalare-Wke forms. 

U.S.N.M., 506870. 
9-11. Carinifex newberryi (Lea). Owens Lake, California. U.S.N.M., 251516. 
12-14. Carinifex occidentalis Hanna. Eagle Lake, Lasen Co., California. U.S.N.M., 

120331. 
15. Carinijex occidentalis Hanna. Eagle Lake, California. U.S.N. M., 120333. 
16-21. Carinifex occidentalis Hanna. Eagle Lake, California. U.S.N.M., 120331. 

Figures 12-21 show range of variation 

All figures are enlarged about 1% times 



1 11 ust rat ions of the Anatomy and of Shells 461 





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17 



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20 

PLATE 112 



^---s 



21 



462 The Molluscan Family Planorbidae 



PLATE 113 

Shells of Planorbidae 

1-4. Carinifex newbcrryi (Lea). Canoe Creek, California. Type locality. U.S.N .M., 

9254. 
5,6. Ccirinifex newbernji (Lea). Canoe Creek, California. Said to be types. See 

Binney, p. 75. U.S.N.M., 9256. 
7,8. Carinifex newberryi (Lea). Canoe Creek, California. Lea Collection, probablj^ 

types. See Binney fig. 120. U.S.N.M., 120991. 
9. Carinifex newberryi (Lea). Canoe Creek. California. Similar in form to malleata. 

U.S.N.M., 2954. 
10,11. Carinifex newberryi (Lea). Canoe Creek, California. LT.S.N.M., 56405. 
12-15. Carinifex newberryi (Lea). Walker Lake, Nevada. U.S.N.M., 349132. 
16-23. Carinifex newberryi (Lea). Lakota Resort, Bear Lake, Utah. B3877. 
24-28. Carinifex newberryi malleata Pilsbry. Pitt River, California. U.S.N.M., 9341. 

29. Carinifex newberryi malleata Pilsbry. Pitt River, California. U.S.N.M., 170772. 

30. Carinifex newberryi malleata Pilsbry. Pitt River, California. Binney's fig. 122. 

U.S.N.M., 9342. 

All figures are enlarged about 1% diameters 



niust rations of the Anatomy and of Shells 



463 











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28 29 

PLATE 113 



30 



464 The MoUuscan Family Plauorhidae 



PLATE 114 

Shells of Planorbidae 

1. Carinijex ponsonbiji E. A. Smith. Lower Klamath Lake. Klamath Falls, Oregon. 

U.S.N.M., 334389. 

2. Carinijex 'ponsonhyi E. A. Smith. Lower Klamath Lake, Klamath Falls, Oregon. 

U.S.N.M., 219749. 
3, 4. Carinijex ponsonhyi E. A. Smith. South end Upi)er Klamath Lake, Oregon. 

B3924. 
5,6. Carinijex ponsonhyi E. A. Smith. South end Upper Khimath Lake, Oregon. 

5, immature. B3924. 
7-9. Carinijex ponsonhiji E. A. Smith. Lower Klamath Lake, Oregon. U.S.N.M., 

337022. 
10,11. Carinijex ponsonhyi E. A. Smith. Upper Klamath Lake, Oregon. U.S.N. M., 

380807. 
12, 13. Carinijex ponsonhyi E. A. Smith. Lower Klamath Lake, Oregon. U.S.N. M., 

334387. 
14,15. Carinijex neieherryi (Lea). Canoe Creek, California. Inunature. IT .S.N. M., 

9256. 

16. Carinijex newberryi (Lea). Canoe Creek, California. Immature. U.S.N.M., 56405. 

17. Carinijex occidentaUs Hanna. Eagle Lake, California. Immature. U.S.N.M., 120333. 

18. Carinijex ponsonhyi E. A. Smith. Klamath Falls, Lower Klamatli Lake, Oregon. 

Immature. U.S.N.M., 510024. 
19-24. Carinijex newberryi minor Cooper. Clear Lake, California. From Lea coll. 

U.S.N.M., 121025. 
25-28. Carinijex newherryi subrotuncla Pilsbry. Proc. Acad. Nat. Sci. Phil., 86, plate 11, 

figs. 2, 2a, 2b, type; 3, paratype. 

Figures 1-13, 25-28 are enlarged about li/-> diameters; 
figs. 17-24 are enlarged 3 diameters. 



IUustratio)is oj the Anatoiny and of Shells 



465 




W ^w ^^^ 





14 



15 



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16 



17 



18 



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466 The Molluscan Family Planorhidae 



PLATE 115 

Shells of Planorbidae 

1. Helisoma caribacum (Orb.). Jocolo, Guatemala. Immature. B3869. 

2-4. Helisoma caloderma (Pilsbry). Esmeralda, Guatemala. Cotypes. U.I., Z28577. 

5-7. Helisoma eyerdami Clench and Aguayo. Lake Miragoane, 2 miles southeast of 

Miragoane, Haiti. Paratypes. M.C.Z., 83888. 
8, 9. Carinijex jacksonensis J. Henderson. Jackson's Lake, Wj-oming. From type lot. 

B3925. 
10-13. Carinijex jacksonensis J. Henderson. Jackson's Lake, Wyoming. From type lot. 

U.S.N.M., 510045. 
14. Porapholyx klamathensis F. C. Baker. East side Upper Klamath Lake, 13 miles 

north of Klamath Falls, Oregon. Holotype. U.S.N.M., 406024. 
15-17. Parapholyx klamathensis F. C. Baker. Same locality as above. Paratypes. 

U.S.N.M., 406024. 

18. Parapholyx klamathensis F. C. Baker. Same locality as above. From type lot. 

U.S.N.M., 406024. 

19. Parapholyx klamathensis F. C. Baker. Same locality as above. From type lot; 

slightly co.state. U.S.N.M., 406024. 

20. Parapholyx klamathensis F. C. Baker. Same locality as above. From type lot; 

with diagonal grooves. U.S.N.M., 406024. 
21-23. Parapholyx klamathensis F. C. Baker. Klamath Falls, Oregon. Small form. 

No. 23, costate. U.S.N.M., 219748. 
24-26. Parapholyx effusa costata (Hemphill). Dalles of the Columbia River, Oregon. 

Type locality. U.S.N.M., 47520. 
27. Parapholyx effusa dalli F. C. Baker. Klamath Falls, Oregon. Holotype. U.S.N.M., 

219747. 
28-30. Parapholyx effusa dalli F. C. Baker. Klamath Falls, Oregon. Paratypes. 

U.S.N.M., 219747. 

Figures 1-7, 24-30 are enlarged about four diameters; 
figs. 8-23 are enlarged about two diameters. 



lllusiratioDs of the Anatomy niid of Shells 



467 



^9 





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14 



15 





18 



19 



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24 



25 



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13 




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17 




21 



20 






22 



26 



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28 29 

PLATE 115 



23 



^;<fe 



30 



468 The Molluscan Family Planorbidae 



PLATE 116 



Shells of Planorbidae 



1,2. Parapholyx effusa (Lea). Sacramento River, California. T.vpe localit\'. Probably 

type lot. U.S.N.M., 121167. 
3. Parapholyx cffusa (Lea). Sacramento River, California. Type localit,y. U.S.N. M., 

121133. 
4-6. Parapholyx effusa (Lea). Oregon City, Oregon. U.S.N.M.. 520085. 
7,8. Parapholyx effusa neritoides (Hemphill). Dalles of the Columbia River, Oregon. 

Type locality. U.S.N.M., 36615. 
9-11. Parapholyx effusa neritoidcs (Hemphill). Dalles of the Columbia River, Oregon. 

Type locality. U.S.N.M., 37518. 
12,13. Parapholyx effusa costata (Hemphill). Dalles of the Columbia River, Oregon. 

Smooth form. U.S.N.M., 47519. 
14. Parapholyx effusa costata (Hemphill). Dalles of the Columbia River, Oregon. 

Smooth form. U.S.N.M., 36617. 
15-17. Parapholyx effusa diagonalis J. Henderson. Crater Lake, Oregon. Type locality. 

B3926. 
18. Parapholyx solida (Dall). White Pine, Nevada. Lectotype. U.S.N.M., 56409. 
19,20. Parapholyx solida (Dall). White Pine, Nevada. Paratypes. U.S.N.M., 56409. 
21. Parapholyx solida (Dall). White Pine, Nevada. U.S.N.M., 75438. 
22,25,26. Parapholyx solida (BaW). White Pine, Nevada. U.S.N.M., 24839. 
23,24. Parapholyx solida (Dall). White Pine, Nevada. 24, slightly costate. U.S.N.M., 

56410. 
27-30. Parapholyx mailliardi Hanna. Eagle Lake, California. Type locality. U.S.N.M., 

47652. 

All figm'es are enlarged about three diameters 




Illustrations of the Anatomy and of Shells 469 





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28 



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30 



PLATE 116 



470 The Molluscan Family Planorhidae 



PLATE 117 

Shells of Planorbidae 

1-6. Parapholyx pusilla F. C. Baker. Six miles west of Pyramid Lake, Nevada. 

Figm-e 1, holotype; 2-5, paratypes; 6, costate specimen. U.S.N.M., 308925. 
7-14. Parapholyx nevadeyisis J. Henderson. Pyramid Lake, Nevada. U.S.N.M., 75440. 

15. Parapholyx nevadensis J. Henderson. Pyramid Lake, Nevada. Scalariform speci- 

men. U.S.N.M., 126765. 

16. Parapholyx nevadensis J. Henderson. Pyramid Lake, Nevada. LlS.N.M., 75439. 
17-26. Parapholyx nevadensis J. Henderson. Pyramid Lake, Nevada. \'ariation in 

form, neritoid to bulimoid. U.S.N.M., 63493. 
27-30. Parapholyx mailliardi Hanna. Eagle Lake, California. From type lot. C.A.S., 
23040. 

All figures are enlarged about 3y> diameters 



Illustrations oj the Anatomy and of Shells 471 






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30 



472 The MoUuscan Family Planorbidae 



PLATE 118 

Shells of Planorbidae 

1. Planorbula armigcra (Say). East Nebraska. U.S.N.M., 526054. 

2. Planorbula armigera palustris F. C. Baker. Mason City, Iowa. U.S.N.M., 527656. 

3. Planorbula crassilabris (Walker). Douglas Lake, Michigan. U.S.N.M., 251213. 

4. Planorbula armigera indianensis F. C. Baker. Mt. Vernon, Indiana. U.I., Z2891. 

5. Planorbula jenksii (H. F. Carpenter). Nayat, Rhode Ishind. B1195. 

6. Planorbula smithi F. C. Baker. Stevenson, Alabama. U.S.N.M., 321196. 

7. Planorbula ivhcatleyi (Lea). Bohgee, Alabama. B1194. 

8. Planorbula campestris (Dawson). High Bluff, Manitoba. U.S.N.M., 63393. 

Figures 1-8 show the folds within the aperture of each species 

9. Planorbula armigera (Say). East Nebraska. U.S.N.M., 526054. 

10. Planorbula jenksii (H. F. Carpenter). Medford, Massachusetts. U.S.N.M., 41411. 

11. Planorbula smithi F. C. Baker. Stevenson, Alabama. U.S.N.M., 321196. 

12. Planorbula smithi F. C. Baker. Stevenson, Ahibama. Specimen with double 

parietal lamella. U.S.N .M., 321196. 

Figures 9-12 show the form of the parietal lamella in three species 

13-15. Planorbula armigera (Say). East Nebraska. U.S.N .M., 526054. 

16. Planorbula armigera variety? Camp Colfax, La Porte Co., Indiana. U.I., Z27094a. 

17-19. Planorbula armigera variety? Camp Colfax, Indiana. U.I., Z27094b. 

20-22. Planorbula crassilabris (Walker). Hamtramck, Wayne Co., Michigan. Type 

locality. B1200. 
23-25. Planorbula crassilabris (Walker). Carr's Slough, Brookston, White Co., Indiana. 

U.I., Z27086. 
26. Planorbula armigera variety? Big slough near Mason City, Iowa. Pathologic. 

U.S.N.M., 527656. 
27-30. Planorbula jenksii (H. F. Carpenter). Nayat, Rhode Island. B1195. 

31. Planorbula armigera (Say). East Nebraska. U.S.N.M., 526054. 

32. Planorbula crassilabris (Walker). Brookston, Indiana. U.I., Z27086. 

33. Planorbula wheatleyi (Lea). Boligee, Alabama. B1194. 

Figures 31-33 show condition of crest behind aperture 
All figures are enlarged about four diameters 



Illustrations of the Anatomy and of Shells 473 














10 



11 




13 16 









14 



17 




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26 



19 





31 



32 



20 




21 




22 




27 




28 




33 




12 




23 




24 




25 




29 




30 



PLATE 118 



474 The Molluscan Family Planorhidae 



PLATE 119 

Shells of Planorbidae 

1-3. Planorbula armigera iiidianeyisis F. C. Baker. Uniontown Road, 2 miles southwest 
of Mt. Vernon, Indiana. 1, holotype; 2, 3, paratypes. U.I., P2833. 

4-6. Planorbula jenksii (H. F. Carpenter). Medford, Massachusetts. U.S.N.M., 41411. 

7,8. Pkmorbula wheatlcyi (Lea). Catoma, Montgomery Co., Alabama. Type. U.S.N. M., 
29292. 

9. Planorbula irhcatlcyi (Lea). Catoma Creek, Montgomery Co., Alabama. U.S.X.M., 

120929. 

10. Planorbula smithi F. C. Baker. Stevenson, Alabama. Holotype. U.S.N.M., 321196. 
11, 12. Planorbula smithi F. C. Baker. Stevenson, Alabama. Paratypes. U.S.N.M., 

321196. 
13. Planorbula christyl (Dall) {^ campestris Dawson). High Bluff, Manitoba. Figured 

type, Alaska Moll., plate ii, figs. 10, 11. U.S.N.M., 63393. 
14,15. Planorbula christyl (Dall). High BlutT. Manitoba. Paratypes. U.S.N.M., 63393. 
1(5-21. Helisoma columbiense F. C. Baker. Lake La Hache, Caribou Dist., British 

Columbia. 16, holotype; 17-21, paratypes. M.C.Z., 93710. 
22-25. Helisoma caribaeum cubcnse F. C. Baker. Zapata Swamp, Cuba. Marl between 

layers of peat. 22, holotype; 23-25, paratypes. U.S.N.M., 404719. 

Figures 1-15 are enlarged about 3^/4 diameters; figs. 16-25 
are enlarged about 1% diameters. 



Illustrations of the Anatoiity and of Shells 



475 




476 The Molluscan Family Plauorbidac 



PLATE 120 

Shells of Planorbidae 

1-10. Menetus opercularis (Gould). Mountain Lake, San Francisco, California. 

U.S.N.M., 47627. 
11,12. Menetus cooperi F. C. Baker { = planulatus Cooper). Whidby's Island, Puget 

Sound, Washington. Type locality. U.S.N.M., 152185. 

13. Menetus cooperi F. C. Baker. Whidby's Island, Puget Sound, Washington. Holo- 

type of M. planulatus. Binney's fig. 209 (No. 9118). U.S.N.M., 29280a. 

14. Menetus cooperi F. C. Baker. Whidby's Island, Puget Sound, Washington. Co- 

type of M. planulatus. U.S.N.M., 29280. 

15-18. Menetus cooperi F. C. Baker. Lake Union, Washington. U.S.N.M., 253617. 

19-21. Menetus cooperi callioglyptus (Vanatta). Freeport, Washington. Cotypes. 
Hemphill coll. U.S.N.M., 47630. 

22. Menetus cooperi F. C. Baker. Olga, Washington. U.S.N.M., 216936. 

23-26. Menetus cooperi rnultilineatus (Vanatta). Pass Lake, Fidalgo Island, Washing- 
ton. U.S.N.M., 346742. 

27. Menetus cooperi F. C. Baker. Bellingham, Washington. Very flat spire. IT .S.N. M., 

525100. 

28. Menetus cooperi F. C. Baker. Lake Washington, Seattle, Washington. U.S.N, M., 

169070. 
29-31. Menetus cooperi midtilineatus (Vanatta). Salem, Oregon. Type locality. B3927. 
32. Parapholyx solida optima (Pilsbry). Lake Bigler, Nevada. Paratype. A.N.S.P., 

125363. 

Figures 1-31 are enlarged about four diameters; fig. 32 
is enlarged two diameters. 



Illustrations of the Anatonnj and of Shells 477 






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11 



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15 



16 



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23 



24 




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26 



27 



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29 



30 



31 



32 



PLATE 120 



478 The Molluscan Family Planorhidae 



PLATE 121 

Shells of Planorbidae 

1-5. Menetus ccntcrvillcnsk (Tryon). Novo, California. U.S.N .M., 47639. 
6-8. Menetus ceniervillemis (Tryon). Bear Lake, San Bernardino Mt.s.. California. 
U.S.N.M., 175089. 

9, 10. Menetus labiatus F. C. Baker. Terminal Island, Los Angeles Co., California. 
Paratypes. U.S.N. M., 190021. 

11. Menetus labiatus F. C. Baker. Terminal Island, Los Angeles Co., California. 
Holotype. U.S.N.M., 190021. 

12-18. Menetus portlanclensis F. C. Baker. Tanner Creek, Portland, Oregon. 12, holo- 
type; 13-18, paratypes. U.S.N.M., 184182. 

19,20. Meyietus cooperi crassilabris F. C. Baker. Seattle, Washington. 20, holotype; 
19, paratype. U.S.N.M., 214590. 

21. Menetus cooperi crassilabris F. C. Baker. Portland, Oregon. U.S.N. M., 99302. 

22,25. Menetus dilatatus (Gould). Hingham, Massachusetts. Lea coll. Type locality. 
U.S.N.M., 121002. 

23,27,28. Menetus dilatatus buehanensis (Lea). Cincinnati, Ohio. Lea coll. Types. 
U.S.N.M., 120948. 

24,30. Menetus dilatatus buehanensis (Lea). Half mile west of Luray, Virginia. Varia- 
tion toward dUatatus. U.S.N.M., 473961. 

26. Menetus dilatatus (Gould). Medford, Massachusetts. U.S.N.M., 41725. 

29. Menetus dilatatus buchanenMs (Lea). Near Luray, Virginia. Pathologic. U.S.N.M., 
473961. 

31. Menetus dilatatus buehanensis (Lea). Mt. Pleasant, District of Columbia. 
U.S.N.M., 227832. 

32,35,36. Menetus dilatatus pennsylvanicus PiLsbry. Three and one-half miles south- 
west of Cambridge, Maryland. B168. 

33. Menetus dilatatus buehanensis (Lea). Harbert, Berrien Co., Michigan. U.M., 88030. 

34. Menetus alahaniensis (PiLsbry). Woodville, Jackson Co., Alabama. Type locality. 

U.M., 85913. 

37. Menetus alabamensis (Pilsbry). Woodville, Alabama. Part of tyjie lot. B3928. 

38. Menetus alabamensis (Pilsbry). Woodville, Alabama. Type locality. U.M., 85913. 

39. Menetus alabamensis (Pilsbry). Woodville, Alabama. Paratype. U.S.N.M., 129005. 
40,41. Menetus alabamensis avus (Pilsbry). Hammock near St. Johns River, Florida. 

U.S.N.M., 101698. 
42-44. Menetus brogniartianus (Lea). Cincinnati, Ohio. Lea coll. 42, lectotype; 43-44, 
paratypes. U.S.N.M., 120981. 



Illustrations of the Auatoiiiy ruid of Shells 479 





^^^^^# 







10 






15 




16 



17 



20 21 



18 



22 23 



19 






24 







25 



30 31 



26 



27 



28 29 






32 



33 34 





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35 



36 



37 38 



39 





42 





40 41 



43 



44 



PLATE 121 



480 The Molluscan Family Planorhidae 



PLATE 122 

Shells of Planorhidae 

1,2. Menetus cooperi F. C. Baker. Blue Lake, Grand Coulee, Washington. B3935. 

3-6. Menetus cooperi planospirus F. C. Baker. Orcas Island, Puget Sound, Wash- 
ington. Figure 5, holotype; 3, 4, 6, paratypes. Figure 5 shows well the very 
flat spire. M.C.Z., 31583. 

7. Menetus cooperi F. C. Baker. Two miles north of Petaluma, California. U.S.N.M., 

531171. 

8. Menetus cooperi calUoghjptus (Vanatta). Quamichan Lake, British Columbia. 

B2030. 
9-12. Menetus cooperi multilincatus (Vanatta). Salem, Oregon. Type locality. B3929. 

13. Menetus cooperi crassilabris F. C. Baker. Colma, San Mateo Co., California. 

U.S.N.M., 525095. 

14. Promenetus exncuous (Say). Chimney Point, Hospital Creek, Lake Champlain, 

Vermont. U.S.N.M., 336591. 
15-18. Promenetus exacuous (Say). New York, New York. B3930. 
19. Promenetus exacuous (Say). West Lake Okoboji, Iowa. U.S.N.M., 475975. 
20-22. Promenetus exacuous mcgas (Dall). Birtle, Manitoba. Types. U.S.N.M., 63391. 
23-25. Menetus coloradoensis F. C. Baker. Swamp, head of Eldora Lake, near 

Eldora, Colorado. Figure 25, holotype; 23, 24, paratypes. U.C, 10114. 
26-28. Promenetus exacuous variety? Gresham Lake, between Gresham and Ward, 

Boulder Co., Colorado. U.C, 526. 

All figures are enlarged about four diameters 



Illustrations oj the Anatomy and of Shells 



481 




PLATE 122 



482 The Molluscan Family Planorbidae 



PLATE 123 

Shells of Planorbidae 

I. Menetus alabamensis avus (Pilsbry). South end Lake Panasofflee, Sumter Co., 

Florida. U.S.N.M., 211002. 
2-10. Parapholyx klamathensis sinitsini F. C. Baker. Bercley Spring, 14 miles north 
of Klamath Falls, Oregon. Figure 2, holotype; 3, 4, paratypes; U.S.N.M.. 
531029. Figures 5-10, locotypes; U.S.N. M., 531064. 

II. Menetus sampsuni (Ancey). Pond in Flat Creek bottom, near Sedalia, Missouri. 

Part of type lot. B166. 
12,13. Menetus alabatnensis (Pilsbry). Temporary pond half mile south of Fountain, 

Illinois. B3923. 
14-16. Menetus sampsoni (Ancey). Pond in Flat Creek bottom, near Sedalia, Missouri. 

Type locality. M.C.Z., 4900. 
17-19. Promenetus hudsonicus (Pilsbry). Four miles southeast of Canandaigua, in 

beach pond, east side Canandaigua Lake, New York. B2904. 
20-22. Menetus dilatatus floridensis F. C. Baker. St. Johns River, Palatka, Florida. 

Figure 20, holotype; 21, 22, paratypes. U.S.N.M., 37585. 
23-25. Menetus uUgmosu-s (Vanatta). Devonshire Swam]), near Hamilton, Bermuda. 

M.C.Z., 108996. 
26. Menetus cooperi crassilabris F. C. Baker. Colma, San Mateo Co., California. 

U.S.N.M., 525095. 
27,28. Menetus uUginosus (Vanatta). Proc. Phil. Acad. Sci., Vol. 62, p. 669, f^g. 2. 

Pembroke Marsh, near Hamilton, Bermuda. Types. 
29,30. Promenetus imus (Vanatta). Proc. Phil. Acad. Sci., Vol. 62, p. 669, fig. 3. 

Bermuda. Types. 
31-33. Menetus sampsoni (Ancey). Meredosia, Illinois. B2018. 
Zi,35. Pro7nenetus umbilicateUus (Ckll.). Plummers Point, Lake Butte des Morts, 

Wisconsin. B2101. 
36. Promenetus umbilicateUus (Ckll.). L"'^pper Dells, Kilbourn, Wisconsin. B2102. 
37-39. Promenetus rubellus (Sterki). Ditch south of New Philadelphia, Ohio. Cotypes. 

B160. 

Figures 2 to 10 are enlarged about two diameters; figs. 1, 11 to 26, 31 to 33, 

37 to 39, six diameters; figs. 34 to 36, four diameters; figs. 27 to 30, 

one-half size of original figures, but enlargement of 

shells is about five diameters. 



Illustrations of the Anatonnj and of Shells 483 



•i*^« %r< 



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28 



29 



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38 





31 



34 37 

PLATE 123 



39 



484 The Molluscan Family Plauorbidae 



PLATE 124 

Shells of Planorbidae 

1,2. Drepanotrema anatimim (Orb.). Para, Brazil. U.S.N.M., 348535. 

3. Drepanotrema anatinum (Orb.). Para, Brazil. M.C.Z., 72832. 

4-6. Drepanotrema anaiinmn (Orb.). Lake Miragoane, two miles SE of Miragoane, 

Haiti. M.C.Z., 83729. 
7. Drepanotrema anatinum (Orb.). Jamaica. {^ Planorhis haldemani C. B. Adams.) 

Lea Collection, probably part of original lot of haldemani. U.S.N .M., 94758. 
8-10. Drepanotrema anatinum (Orb.). Esperanza, Cuba. Type locality of Planorbis 

esperanzensis Tryon. M.C.Z., 85875. 
11-13. Drepanotrema anatinum (Orb.). Baron Hills, Trelawny, Jamaica. {^^ Planorbis 

haldemani C. B. Adams.) M.C.Z., 65839. 
14-20. Drepanotrema parapseide (Orb.). Buena Vista, Santa Cruz, Bolivia. U.M., 

87196. 
21-28. Drepanotrema ahenum H. B. Baker. Tuccas, Venezuela. Type lot, showing age 

variation in shell. U.M., 87164. 
29,31,32. Drepanotrema lucidum (Pfr.). Juninaguas, Dept. Loreto, Peru. U.S.N.M., 

381510. 
30. Drepanotrema anatinum (Orb.). Juninaguas, Dept. Loreto, Peru. LT.S.N.M., with 

381510. 

All figures are enlarged about foiu- diameters 



Illustrations of the Aiiatonnj and of Shells 485 





12 









10 




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9^9 

^4 15 



13 



16 





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PLATE 124 



486 The Molluscan Family Plauorbidae 



PLATE 125 

Shells of Planorbidae 

1,4,6,7. Drepanotrcma lucidum (Pfeiffer). Lagumi del Bili, Alacranes Mts., Cuba. 

M.C.Z., 129991. 
2,3. Drepanotrema lucidum (Pfeiffer). St. Louis, Dejit. du Sud, Haiti. Immature 

shells. U.S.N.M., 402809. 
5. Drepanotrema Incidum (Pfeiffer). Maggoty, St. Elizabeth, Jamaica. IT .S.N. M., 

376088. 

8. Drepanotrema lucidum (Pfeiffer). Jamaica. {^^ Pkntorbis redfieldi C. B. Adams.) 

Lea Collection. Possibly part of original lot of redfieldi. U.S.N.M., 94757. 

9, 10. Drepanotrema lucidum (Pfeiffer). Jealousy Stream, St. Croix. U.S.X.M., 423966. 
11-17. Drepanotrema lucidum (Pfeiffer). Large variety with closely coiled whorls. 

Half mile NE of Orange Creek, Cat Island, Bahamas. M.C.Z., 107179. 
18-21. Drepanotrema melleum (Lutz). Rio de Janeiro, Brazil. U.S.N.M., 535918. 

All figures are enlarged about four diameters 



Illustrations of the Anatomy and of Shells 

^1 



487 




488 The MoUuscan Family Planorhidae 



PLATE 126 

Sliells of Planorbidae 

1-5. Drepanotrcma castcuuonitcns (Pils. and Van.). Near Maldonado, Uiuguaj'. Tj-pe 
locality. U.S.N.M., 151668. 

6. Drepanotrcma hofftnanni F. C. Baker. Isabela, Puerto Rico. Holotype. B3952. 

7-9. Drepanotrema hoffmanni F. C. Baker. Isabela, Puerto Rico. Paratypes. B3953. 

10-12. Drepanotrema hojfmanni F. C. Baker. Near San Juan, Puerto Rico. Age 
variation. U.S.N.M., 420573. 

13. Drepanotrema kermatoide (Orb.). Puerto Haberton, Argentina. U.S.N. M., 362857. 

14-16. Drepanotrema kermatoide (Orb.). Lima, Peru. Type locality. Figure 14 shows 
an immature specimen. LT.S.N.M., 20705. 

17-19. Drepanotrema ciiltratum anitense (Cooper). Laguna, Santa Rita, Lower Cali- 
fornia. U.S.N.M., 129292. 

All figures are enlarged about four diameters 



lUustratiois oj the Anatomy and of Shells 



489 









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19 



18 



PLATE 126 



490 The Molluscan Famih/ Planorbidae 



PLATE 127 

Shells of Planorbidae 

1-3. Drepanotrema cimcx (Moricand). Valle de Yumuri, Matanzas, Cuba. M.C.Z., 

129995. 
4-6. Drepanotrema cultratum (Orb.). Painters Pond, Painters, Antigua. U.S.N. M., 

272282. 

7,8. Drepanotrema cimex (Moricand). Hunts Bay, St. Andrew, Jamaica. U.S.X.M., 

378054. 
9-12. Drepanotrema cultratum duenafsianum (Tristram). Pools alono; i-aihvay near 

Lake Amatitlan, Guatemala. B1258. 
13-15. Drepanotrema cimex pistiae H. B. Baker. Rincon del Valle, near Caracas, 

Venezuela. U.S.N.M., 362133. 
IQ. Drepanotrema cimex (Moricand). Jamaica. {^ Planorbis macnabianus C. B. 

Adams.) Lea Collection, probably part of original lot. U.S.N.M., 94756. 
17-19. Drepanotrema depressissimum (Moricand). Bahia, Brazil. Paratypes. M.C.Z., 

31432. 

All figures are enlarged about four diameters 



Illustrations of the Anatotny and of Shells 491 




492 The Molluscan Family Planorhidae 



PLATE 128 

Shells of Planorbidac 

1.2. Drcpanotrema cultratum panuco Pilsbry. Tampico, Mexico. B1183. 

3-5. Drepanotrema cultratum panuco Pilsbry. Pasture west of San Dieguito, San Luis 

Potosi Co., Mexico. Locotypes. B2124. 
6. Drcpanotrema cultratum labrosum Pilsbry. Brownsville, Texas. U.S.N. M., 273933. 
7-10. Drepanotrema cultratum labrosum Pilsbry. Brownsville, Texas. Locotypes. 

B1192. 
11-16. Drepanotrema sumichrasti (Crosse and Fischer). Barbovu' Lathrop Trail, Barro 

Colorado Island, Gatun Lake, Canal Zone. B3967. 
17-19. Drepanotrema cimex (Moricand). Brazil. U.S.N.M., 121018. 
20-22. Drepanotrona cimex (Moricand). Anapolis, Guyoz, Brazil. M.C.Z., 65716. 
23-25. Drepanotrema peninsularis (Cooper). {^Drepanotrema anathuon) . Santa 

Anita, Lower California. U.S.N.M., 129291. 
26-30. Tropicorbis obstructns (Morelet). Tampico, Mexico. U.L, Z28550. 
31-33. Tropicorbis obstructns (Morelet). Lake Amatitlan, Guatemala. B2125. 

Figures 1 to 30 are enlarged about five diameters; figs. 31 to 33 
are enlarged about four diameters. 



Illustrations of the Anatomy and of Shells 493 



11 



26 





12 



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27 



13 






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28 



14 



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19 22 25 33 



22 25 

PLATE 128 



494 The Molluscan Family Planorbidae 



PLATE 129 

Shells of Planorbidae 

1-3. Tropicorbis orbiculus (Morelet). Near San Miguel, Cozumel Island, Quintana 

Roo, Mexico. M.C.Z., 75102. 
4. Tropicorbis obstructus (Morelet). Same as above. M.C.Z., 75102. 
5-7. Tropicorbis orbiculus (Morelet). {^^ Planorbis licbmanni Dunker). Vera Cruz, 

Mexico. U.S.N.M., 210881. 
8,9. Tropicorbis obstructus (Morelet). Same locality as above. U.S.N .M., 210881. 
10-15. Tropicorbis orbiculus (Morelet). Chamiai Creek, below Valles, Mexico. U.I., 

Z28528. 
16. Tropicorbis orbiculus (Morelet). Catanas Lake, El Abra, Mexico. B1191. 
17-22. Tropicorbis obstructus donbilli (Tristram). Edentate. Guadalupe River, Victoria 

Co., Texas. U.S.N.M., 464970. 
23-25. Tropicorbis obstructus donbilli (Tristram). Edentate. Brownsville, Texas. 

B1187. 
26-31. Tropicorbis orbiculus dunkcri F. C. Baker. New name. Dry pool near Tampico, 

Mexico. B1184. 
32-36. Tropicorbis orbicidus dunkcri F. C. Baker. Los Canoas, Mexico. B2113. 
37-42. Drepanotrema heteropleurus Pilsbry and Vanatta. Lake Titicaca, Peru. Topo- 

types. Agassiz Expedition. 

All figures are enlarged about two diameters 



llhstrations of the Anatomy and of Shells 



495 



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PLATE 129 



496 Tiie Molluscan Family Planorbidae 



PLATE 130 

Shells of Planorbidae 

1-3. Tropicorbis gracilcntus (Gould). Colorado Desert. Binney's fig. 183, p. 108. Holo- 

type. U.S.N.M., 26477. 
4-12. Tropicorbis gracilentus (Gould). San Marcos, Texas, in drift adjoining fish 

hatchery. Figure 10 shows closely coiled whorls like those of Tropicorbis orbi- 

culus. B3298. 
13-17. Tropicorbis maya (Morelet). Merida, Yucatan. M.C.Z., 59646. 
18-20. Tropicorbis hovancnsis (PfeifTer). Havana, Cuba. Type locality. U.M., 84039. 
21-25. Tropicorbis havaiicnsis (Pfciffer). New Orleans, Louisiana. A small \-ariety. 

B3954. 
26. Tropicorbis havancnsis (Pfeiffer). Guayos, Santa Clara Prov., Cuba. U.M., 84038. 
27-28. Tropicorbis havanensis (Pfeiffer). New Braunfels, Texas. M.C.Z., 13622. 
29-32. Tropicorbis philippiamis (Dunker). Asuncion, Paraguay. Figure 31, loosely 

coiled. M.C.Z., 62490. 
33,34. Tropicorbis philippianm (Dunker). Espcranza dc Santa Fe, Argentina. M.C.Z., 

64963. 
35-37. Tropicorbis centimeimlis (Lutz). Ceara Miriin, Rio Grande do Norte, Brazil. 

Type locality. M.C.Z., 92825. 
38-41. Tropicorbis })crc(jrinus (Orbigny). Rio Grande de Sul, Brazil. M.C.Z., 75376. 

All figures are enlarged about two diameters 



Illustratious of the Anatomy and of Shells 497 



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PLATE 130 



498 The Molluscan Family Planorbidae 



PLATE 131 

Shells of Planorbidae 

1^. Tropicorbis isthmicus (Pilsbiy). Panama City, Panama. Type locality. U.M., 

88180. 
5-7. Tropicorbis isthmicus (Pilsbry). Miraflores Lake, Panama. U.M.. 88181. 
8-10. Tropicorbis decipiens (C. B. Adams). Rockport, Jamaica. B3966. 
11. Tropicorbis decipiens (C. B. Adams). Puerto Rico. LT.L, Z40460. 
12-14. Tropicorbis chilensis (Clessin). Valparaiso, Chile. M.C.Z., 74655. 
15-24. Tropicorbis obstructus donbilli (Tri.stram). Dr\' pool in Tampico, Mexico. 

B1189. 
25,26. Tropicorbis obstructus donbilli (Tristram). Brownsville, Texas. B127. 
27-31. Taphius andecolus montanus (Orbigny). Tanja (Oroya), Peru. M.C.Z., 36702. 
32-35. Taphius andecolus (Orbigny). Puoa, Peru. U.I., Z40575. 
36-40. Taphius subpronus (von Martens). Terrialba, Costa Rica. U.S.N.M., 162827. 

Figures 1 to 35 are enlarged about two diameters; figs. 36 to 40, four diameters. 



lUustratiois of the Anatomy and of Shells 



499 




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PLATE 131 



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500 The Molluscan Family Planorbidae 



PLATE 132 

Shells of Planorbidae 

1-3. Tropicorbis paUidus (C. B. Adams). King.ston, Jamaica. U.I., Z40466. 

4,5. Tropicorbis pallidus (C. B. Adams). Tucaras, Venezuela. U.M., 89990. 

6-9. Tropicorbis kuhnianus (Dunker). Bejuma, Venezuela. U.M., 89991. 

10-12. Tropicorbis stramineus (Dunker). Venezuela. Paratypes. Ex Dunker. M.C.Z., 

74654. 
13,14. Tropicorbis stramineus (Dunker). Lagoa Giboia, Municipio de Aquraz, Ceara, 

Brazil. M.C.Z., 65720. 
15-21. Tropicorbis riisei {'Dunker) . Lares, Puerto Rico. B3955. 
22,23. Tropicorbis ineridaensis (Preston). Merida, Venezuela. VI., Z40463. 
24-28. Tropicorbis fieldi (Tryon). Gatun, Panama Canal. Type locality. M.C.Z., 21187. 
29,30. Tropicorbis fieldi (Tryon). Near Granada, Nicaragua. M.C.Z., 4534. 
31,32. Tropicorbis bourcardianus (Preston). Mexico. U.S.N.M., 202523. 
33-35. Tropicorbis gundlachi (Dunker) {^stramineus). Trinidad. U.I., Z40461. 

All figures are enlarged about three diameters 



Illustrations of the Anatomy and of Shells 501 




502 The Molluscan Family Planorhidae 



PLATE 133 

Shells of Planorhidae 

1-3. Tropicorbis petenensis Morelet. Tehaimtepec, Mexico. M.C.Z., 64995. 

4-9. Tropicorbis tcpiceiisis (Martens). Tepic, Guadalajara, Mexico. U.S.N.M., 102211. 

10-13. Tropicorbis heloicus (Orbigny). In small creek back of the Cerro, Montevideo, 

Uruguay. Type locality. U.S.N.M., 535720. 
14-17. Tropicorbis nigrilabris (Lutz). Rio de Janeiro, Brazil. Type locality. U.S.N.M., 

535713. 
18-21. Tropicorbis janeirensis (Clessin). Bahia, Brazil. U.S.N.M., 152677. 
22. Tropicorbis schrammi (Crosse). Martinique. M.C.Z., 113883. 
23,24. Tropicorbis schrammi (Crosse). Antigua. U.I., Z40465. 
25-27. Tropicorbis dcclivis (Tate). Nicaragua. U.S.N.M., 24006. 
28-33. Tropicorbis obstructiis (Morelet). Pool at Piste, Yucatan. M.C.Z., 59754. 
34,35. Tropicorbis obstructus (Morelet). Falls of the Valles River, Valles, Mexico. 

B2117. 
36-40. Tropicorbis obstructus anodontus (Pilsbry). Reservoir north of Guatemala City, 

Guatemala. Type locality. B2061. 

All figures are enlarged about three diameters 



Illustrations of the Anatomy and of Shells 






4 

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PLATE 133 



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504 The Molluscan Family Planorbidae 



PLATE 134 

Shells of Planorbidae 

1-3. Tropicorbis paparyc7isis (F. Baker). Anapolis, Goyaz, Brazil. M.C.Z., 65717. 

4-6. Tropicorbis albicans (Pfr.). Cuba. U.I., Z40459. 

7. Tropicorbis schrammi (Crosse). Antigua. U.I., Z40465. 

8,9. Tropicorbis dentiferus (C. B. Adams). Bog Walk, St. Catherine, Jamaica. M.C.Z., 

65838. 
10,11. Tropicorbis obstruents (Morelet). Catamas Lake, El Abra, Mexico. B1218. 

12. Tropicorbis shimeki F. C. Baker. Ometope, Nicaragua. Holotype. U.S.N.M., 

534290. 

13, 14. Tropicorbis shitneki F. C. Baker. Ometope, Nicaragua. Paratypes. U.S.N.M., 

534290. 
15-18. Tropicorbis albicans (Pfr.). Mangrove Cay, along Kings Road, Lisbon Point, 
Andros Island, Bahamas. U.S.N. M., 270084. 

19. Tropicorbis albicans (Pfr.). Cuba. U.I., Z40459. 

20. Tropicorbis paparyensis (F. Baker). Anapolis, Brazil. M.C.Z., 65717. 

21. Tropicorbis obstructus donbilli (Tristram). Tamosopo, Mexico. I^.L, Z28545. 

Figures 18 to 21 illustrate form of lamellae in aperture 

22. Tropicorbis obstructus (Morelet). Pistae, Yucatan. M.C.Z., 59754. 

23. Tropicorbis obstructus donbilli (Tristram). Tamosopo, Mexico. U.L, Z28545. 

24. Tropicorbis janeirensis (Clessin). Bahia, Brazil. U.S.N.M., 152677. 

25. Tropicorbis nigrilabris (Lutz). Brazil. U.S.N.M., 535713. 

26. Tropicorbis paparyensis (F. Baker). Anapolis, Brazil. M.C.Z., 65717. 

27. Tropicorbis schrammi (Crosse) . Martinique. U.L, Z40464. 

28. Tropicorbis shimeki F. C. Baker. Coatzocoalcos, Mexico. U.S.N.M., 219696. 

29. Tropicorbis albicans (Pfr.). Mangrove Cay, Andros, Bahamas. U.S.N .M., 270084. 

Figures 22 to 29 illustrate lamellae on parietal wall 
Figures 1 to 11 are enlarged about four diameters; figs. 12 to 29, six diameters. 



Illustrations of the Anatomy and of Shells 505 



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PLATE 134 



506 The Molluscan Family Planorhidae 



PLATE 135 

Shells of Planorbidae 

1-3. Tropicorbis peregrinus (Orbigny). Montevideo, Uruguay. U.S.N. M., 535952. 

4. Tropicorbis peregrinus (Orbigny). Arroyo de Solon, Uruguay. U.S.N.M., 380999. 

5-8. Tropicorbis centimetralis (Lutz). From Lutz. U.S.N. M., 535956. 

9-11. Tropicorbis chilensis (Clessin). Peru. Lea Coll. from Paris Museum. U.S.N. M., 

126412. 
12,13. Tropicorbis philippianus (Dunker). Lake near Coma de Ipaguaza, Bolivia 

(15 mi. N.E. of Yacuiba). U.S.N.M., 341049. 
14-16. Tropicorbis meridaensis (Preston). Ruicon de Valle, near Caracas, Venezuela. 

U.S.N.M., 362132. 
17-19. Tropicorbis bourcardiai^us (Preston). Manzanello, Mexico. L'.S.N.M., 219755. 
20,21. Tropicorbis canonicus (Cousin). Soacha, near Bogata, Colombia. M.C.Z. 
22,23. Tropicorbis canonicus (Cousin). 'La Picata' near Bogata, Colombia. M.C.Z. 
24-27. Tropicorbis canonicus (Cousin). Ibarra, Ecuador. M.C.Z., 64967. 
28-31. Tropicorbis trigyrus (Philippi). Small lake near Titicaca, Peru. (14,000 feet 

elevation). U.S.N.M., 271591. 
32-35. Tropicorbis gracilentus (Gould). 30 miles S.W. of Santiago, Mexico. U.S.N.M., 

28384. 

All figures are enlarged about 2i/l> diameters 



Illustrations oj the Anatomy and of Shells 507 



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PLATE 135 



34 



35 



508 The Molluscan Family Planorbidae 



PLATE 136 

Shells of Planorbidae 

1-3. Gyraidus albus (Miiller). Scaly Beck, near Scarborough, England. No. 3 shows 

fine spiral sculpture. Baker coll., 2768. 
4-7. Gyraulus hirsutus (Gould). Lynnfield, Massachusetts. M.C.Z., 34915. 
8-10. Gyrmdus hirsidus (Gould). Lynnfield, Massachusetts. M.C.Z., 34915. 

11. Gyraulus hirsutus (Gould). Lynnfield, Massachusetts. Base of shell showing 

rounded whorls. M.C.Z., 34915. 

12. Gyraidus hirsutus (Gould). Lynnfield, Massachusetts. Hirsute shell showing larger 

and less numerous rows than in albus, fig. 3. 

13-15. Gyraulus deflectus (Say). Miller Bay, Lake Winnebago, Wisconsin. Baker Coll., 

2036. 
16,17. Gyraulus deflect