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New York State Veterinary College 



Simpson, George B, 

Anatoiny and Phjsiology of Polygyra 
albolabris and Umax raaximus 

Cornell University Library 
QL 431.S61 

Anatomy and physiology of Polygyra Albol 

3 1924 001 030 612 








N. Y- 


University of the State of New York 



New York State Museum 

■Frederick' J. H. Merrill Director 

No. 40 Vol. 8 
October 1901 ' 




,) AND 




Division of paleontology 




Mfigm-J 66-3000 


Price 25 cents 

University of the State of New York 

With years of election 

1874 Anson Judd Upson L.H.D. D.D. LL.D. 

Chancellor, Glens Falls 

1892 William Croswell Doane D.D. LL.D. 

Vice-Chancellor, Albany 

1873 Martin I. Townsend M.A. LL.D. i _ _ Troy 

1877 Chauncey M. Depew LL.D. _ _ _ l<Iew York 

1877 Charles E. Fitch LL.B. M.A. L.H.D. - - Rochester 

1877 Orris H. Warren D.D. _ _ _ _ Syracuse 

1878 Whitelaw Reid M.A. LL.D. _ _ _ _ New York 
1881 William H. Watson M.A. M.D. - - - Utica 
1881 Henry E. Turner _-___- Lowville 
1883 St Clair McKelwav M.A. L.H.D. LL.D. D.C.L. Brooklyn . 
1885 Daniel Beach Ph.D. LL.D. _ _ _ Watkins 
1888 Carroll E. Smith LL.D. _ _ _ _ Syracuse 
1890 Pliny T. Sexton LL.D. _ _ _ _ Palmyra 
1890 T. Guilford Smith M.A. C.E. LL.D. - - Buffalo 

1893 Lewis A. Stimson B.A. LL.D, M.D. - - New York 
1895 Albert Vander Veer Ph.D. M.D. - - - Albany 
1895 Charles R. Skinner M.A. LL.D. 

Superintendent of Public Instruction, ex officio 
1897 Chester S. Lord M.A. LL.D. _ _ _ _ Brooklyn 
1897 Timothy L. Woodruff M.A. Lieutenant-Governor, ex officio 

1899 John T. McDoNOUGH LL.B. LL.D. Secretary of State, ex officio 

1900 Thomas A. Hendrick M.A. LL.D. _ _ _ Rochester 

1901 Benjamin B. Odell jr LL.D. Governor, ex officio 

1901 Robert C. Pruyn M.A. _____ Albany 

Elected by regents 

1900 James Russell Parsons jr M.A. 

directors of departments 
1888 Melvil Dewey M.A. State library and Home education 
1890 James Russell Parsons jr M.A. 

Administrative, College and High school defts 
1890 Frederick J. H. Merrill Ph.D. State museum 

University of the State of New York 


New York State Museum 

Frederick J. H. Merrill Director 

No. 40 Yol. 8 
October 1901 







Division of paleontology 




S (si '^ '^ 


Preface 239 

Introduction 241 

Methods and apparatus 241 

Methods of killing and manipulating 241 

Habits 241 

Polygyra albolabris ,.. 244 

Shell 244 

External features 245 

Movement 247 

Food — carnivorous habits 247 

Digestive system 249 

Pedal gland 254 

Generative system 255 

Description of a species of Entozoa 261 

Circulatory system 262 

Nervous system 268 

Special organs of sense 272 

Limax maximus L . 277 

Digestive system 278 

Generative system 279 

Circulatory system 280 

Nervous system 283 

Muscular system 287 

Embryology 290 

Time of laying eggs 293 

Rate of growth 294 

Explanation of plates 

Polygyra albolabris, plates 1-14 295 

Limax maximus, plates 15-28 302 

Index 312 


This work has been written for the use of individual students, 
as well as for classes in schools and colleges. No similar work 
on the snail has been published in this country, and in my own 
investigations I have seriously felt the need of one. 

I have endeavored to write a work which will enable the stu- 
dent, without a previous knowledge of the subject, satisfactorily 
to pursue his investigations. I have, therefore, commenced at the 
beginning, giving explanations in regard to the instruments 
necessary, methods of dissection, how to collect the animals, etc., 
followed by a plain, but full, description of all the organs, with- 
out the use of too many technical terms, and unencumbered by 

I have made very full illustrations of all the organs and parts 
of organs, enabling the student at once to see their form and po- 
sition. These illustrations are accurate copies from nature and 
in no case are they diagrammatic. 

The manuscript of that portion of this work treating of anat- 
omy and physiology was kindly reviewed by Prof. H. A. Pilsbry, 
of Philadelphia, and to him I am indebted for suggestions, spe- 
cially in regard to nomenclature. I am also indebted to Prof. 
E. G. Conklin, of the University of Pennsylvania, who reviewed 
that portion treating of the embryology of L i m a x . 

George B. Simpson 











New York State Museum 


Methods and apparatus 

Specimens of Polygyra and L i m a x may be easily kept 
in captivity by placing them in d box in which there are about 4 
inches of earth covered with dead leaves. The earth must be 
kept moist. The box must be covered with mosquito netting or 
tarlatan. The mosquito netting will be sufficient for adult indi- 
viduals, but the young of L i m a x would escape easily through 
its meshes. 

For the study of the histology and embryology a compound 
microscope is necessary, with 2 inch, f inch and ^ inch objec- 
tives. A dissecting microscope is almost indispensable. I have 
used, for that purpose, one manufactured by Bausch & Lomb of 
Rochester (N. Y.), known as the " laboratory dissecting micro- 
scope," fitted with a Hastings aplanatic lens. A cut of this in- 
strument is given herewith. Two pairs of fine scissors will be 
necessary, one pair with straight points, the other with curved 
points; one or more fine scalpels, and two pairs of fine forceps, 
one straight and the other curved. A pair of stronger forceps and 
a pair of fine pliers will be needed to remove the shell of 
Polygyra. Dissecting needles are also necessary. These 
can be made by forcing the heads of fine needles, by means of 
a pair of pliers, into the end of a round stick of small diameter. 
The point of one of these needles should be bent so as to form 
a hook, first heating the end of the needle to a white heat. 

Methods of killing and manipulating 

I have tried all of the various methods recommended for 
killing Polygyra and L i m a x , and find only one that is 
uniformly successful, and that is drowning. In using hot water 
and various chemicals, in nearly every case the animal is 
more or less contracted, and thus rendered useless for the pur- 


pose of a successful dissection. lu drowning tlie animal, I have 
need a fruit-preserving jar, as being more convenient than a wide- 
mouthed bottle. The jar should be completely filled with water, 
so that, when the cover is fastened on, there will be no air space 
left. The animals being placed in the water and the cover 
screwed on, the jar should be left undisturbed for 48 hours; it 
requiring about that length of time to drown the animals. Ke- 
maining undisturbed, they will die fully extended; but, if the jar 
is disturbed in the meantime, more or less contraction vdll take 
place. The animal when dead should be thoroughly washed to 
free it from all adhering mucus, and placed in alcohol diluted 
with about two thirds the amount of water, additional alcohol 
being added from day to day till the mixture consists of about 75^ 
of alcohol. The animals should then be removed and placed in 
undiluted alcohol, when they will keep indefinitely. If placed at 
once in strong alcohol, the action of the fluid on the integument 
prevents the proper preservation of the internal organs. 

To remove the shell, preparatory to dissecting the animal, 
break the peristome with a small pair of pliers. The remainder 
of the shell can be removed with a pair of forceps, carefully break- 
ing off a small piece of shell at a time till it is removed to the 
apex. The columella can be removed by holding the lower part 
between the thumb and forefinger of the left hand, and turning 
the animal with the right. As the columella is like a screw, the 
animal readily becomes detached by this movement. 

In dissecting the animal, a circular china dish about 4 inches 
in diameter and 2 in depth will be necessary; also a piece of sheet 
cork as large as will lie at the bottom of the dish, fastened to a 
thin sheet of lead with either string or rubber bands. It is best 
to have the lead of the same size as the cork. This leaded cork 
is to be placed in the bottom of the dish, and the dish filled with 
alcohol. If the animal has once been placed in alcohol, all dissec- 
tions should be made in alcohol, but freshly killed specimens may 
be dissected in water, and many of the organs at this time present 
a much more natural appearance than when acted on by alcohol. 
Place the animal on the cork and fasten it down with small pins, 


or^ better yet, with very fine, short needles, inserted through the 
margin of the foot. Then, with the fine pair of scissors, com- 
mencing at the head, cut through the integument along the center 
of the back, taking care not to injure any of the organs below. 
The integument is now to be removed from the dorsal part, 
turned back and fastened to the cork^ removing the needles from 
the margin of the foot and putting them through the edges of the 
integument. All the organs of the anterior part of the snail are 
thus brought into view, and farther dissection of the organs can 
be intelligently made. 

In the case of the L i m a x nearly all the organs will be 
brought into view by turning back the integument; but great 
care must be taken in this genus in cutting through the integu- 
ment not to injure the pulmonary chamber, as it is situated very 
near the surface. Also every precaution should be taken that 
the points of the scissors shall not go below the integument, or 
the intestine and upper surface of the stomach will be mutilated, 
and a successful dissection rendered impossible. 


Polygyra albolabris. The snails of this species are found in 
woods near fields, in ravines and in other situations. They re- 
main concealed through the day when the sun is shining, coming 
forth for their food toward evening and after showers. It is at 
these times that they are most easily found during summer. Fre- 
quently they may be found on the under side of boards, logs and 
stones. During cold weather they hibernate, partially burying 
themselves in the ground, with the apex of the shell downward. 
At this time they are very easily found by scraping away the 
dead leaves so as to expose the surface of the ground. While 
hibernating the animal is completely withdrawn in the shell, the 
mouth of which is closed by a mucous excretion, which becomes 
hardened on exposure to the air. It is stated by nearly all 
writers on this subject that there is always a perforation in this 
membrane to allow the passage of air; but I have observed 
numerous cases where the membrane was entire. 



Limax maximus is founS in gardens, where it is very destructive 
to vegetation. During the day it secretes itself; but it may easily 
be found, by the aid of a lantern, while feeding at night. 


The shell of Polygyra is turbinate, spiral; consisting in 
P. albolabris of five volutions, coiled around a hollow axis 
known as the columella. The columella is open at the base in 
immature specimens, but in adults it is closed by a growth of the 
shell. When the shell emerges from the egg, it consists of one 
volution only. Farther growth of the shell takes place in the 
manner hereafter described. 

The shell consists of three parts or layers: the outer com- 
monly, but wrongly, termed the epidermis — cuticle or Carpen- 
ter's name, periostracum, is preferable; next a prismatic part; 
finally a laminate part. The prismatic and laminate layers are 
of about equal thickness, and together form the greater part of 
the entire thickness of the shell. 

The cuticle is thin; in P. albolabris yellowish brown in 
color. It is without sensation, like the human scarf skin. Its 
office is to protect the shell from chemical action, which other- 
wise would injure or destroy it. After the death of the animal 
it fades and becomes brittle, or is entirely destroyed in situations 
in which during life it would not be affected. 

The shell is formed by the thickened margin of the integument 
covering the visceral mass. According to Carpenter, " the shell, 
as before stated, is formed by the mantle of the shellfish, indeed, 
each layer of it was once a portion of the mantle, either in the 
form of a simple membrane or as a layer of cells, and each layer 
was successively calcified (or hardened by carbonate of lime) and 
thrown off by the mantle to unite with those previously formed.'' 
According to Huxley, the shell growth is not a case of conversion 
but of excretion, and the shell is built up by successive excretions 
of membranous laminae, in which granules of carbonate of lime 
are deposited. 


The prismatic part of the shell is apparently formed by the 
deposition of calcareous matter in prismatic, generally hexagonal, 
cells, which are themselves formed by the successive secretions of 
fenestrated laminae, deposited by the margin of the mantle (pi. 
2, fig. 12 and 15). 

The laminar part is apparently composed of numerous thin 
laminae varying in thickness. In many thin sections which I 
have examined under the miscroscope I have seen no trace of the 
prismatic structure in this part of the shell. The nacreous layer 
is very thin, forming the inner stratum of the shell, and is of a 
somewhat pearly appearance. This layer is a part of the 
laminar stratum, though it eeems to be discernible, and in the 
broken edges of the shell is always distinct and is distinguished 
by its lighter color. 

Till the shell reaches maturity the margin is very thin; but 
when mature the margin becomes greatly thickened and reflected, 
forming a broad peristome (pi. 1, fig. 3, 4-7, 12). It is apparently 
formed by the part of the mantle depositing the prismatic layers, 
as nearly its entire thickness is of prismatic structure .(pi. 2, 
fig. 13, 14). 

If the margin of the shell is broken, it can be repaired by the 
animal; but, if any other part of the shell is broken, complete 
renewal is impossible, as the prismatic and cuticular layers of the 
shell are deposited only by the thickened border of the mantle. 
A mucoid substance in such cases is excreted and becomes calci- 
fied, taking the place of the missing shell; but any considerable 
breakage of the shell, except at the margin, is liable to be fatal 
to the animal. In collecting specimens, sometimes by accident 
the shells were broken; in nearly every case the animals died 
within a few days. 

External features 

The ventral part of the animal is expanded into a locomotor 
organ or foot, which is a thick, vermiform body with a ribbon-like 
ventral disk. The head is situated at the anterior extremity, 
and is obtuse; from it protrude two pair of tentacles, the upper 


and much the longer pair containing the eyes, the lower and 
shorter pair, the olfactory nerves. The mouth is situated at the 
anterior basal part of the head. Immediately below it is the 
opening into the pedal gland. The anterior upper part of the 
body is rounded; the posterior part is more acute. 

The dorsal part of the animal is produced in a spirally coiled 
mass, containing the whole of the digestive gland, and parts of 
the alimentary, circulatory and reproductive organs, and is there- 
fore known as the visceral mass. 

The integument of the foot consists of a thick mucous-secret- 
ing membrane, with a muscular substratum. There are numer- 
ous mucous glands occupying nearly the whole of the membrane. 
The muscular substratum consists of unstriped fibers, arranged 
longitudinally, transversely and obliquely. Interior to this in- 
vestment of the foot is a muscular membrane inclosing the di- 
gestive and reproductive organs, which is sometimes called the 

The dorsal part of the animal is inclosed in the shell and is 
an exact mold of the shell. The integument of this part is very 
thin and semi-transparent and is known as the mantle. Where 
the visceral sac joins the foot the mantle is very much thickened, 
forming a muscular collar, which is the shell-building organ of 
the animal. 

When the animal is at rest or alarmed, the foot is contracted 
entirely within the shell, occupying the space at other times 
filled by the pulmonary cavity. The pulmonary chamber is very 
large and is situated in the outer part of the lower whorl. When 
the foot is protruded, the pulmonary rete still remains in contact 
with the shell, thus leaving a large cavity. It is into the space 
obtained by the collapse of this cavity, when emptied of air, that 
the animal withdraws when contracted. Thus the pulmonary 
chamber of testaceous snails is as much larger than the chamber 
of the naked slugs, as the volume of the foot superadded. 



The snail moves with a slow, gliding motion, produced by the 
muscles of the pedal disk. First the hinder part of the foot is 
drawn up, and the part immediately anterior to it is extended. 
This part is then contracted, and the part immediately anterior 
to it extended. These movements take place the entire length 
of the body, following each other so quickly that a gliding mo- 
tion is produced. This contraction and expansion are confined to 
the central part of the pedal disk, the margins of the foot having 
a lateral undulating movement of their own. 

The movement of the muscles of the middle part of the pedal 
disk gives rise to a very peculiar appearance, as if there were a 
channel through which oval drops of a transparent fluid were 
rushing in quick succession. Each contraction and expansion of 
the muscles of each part of the disk give the appearance of one 
of these drops of fluid, and, as these movements take place in 
rapid succession along the whole length of the foot, beginning 
at the posterior and continuing to the anterior extremity, the 
optical delusion of rushing drops of water is created. 

If a snail is placed on a thin piece of glass, and the under part 
is observed while the snail is in motion, this movement can be 
observed, or if a Limax is held with the fingers in such a 
position that the under part of the body is uppermost, when it 
struggles to escape the appearance is the same, the action of the 
muscles being the same as when the animal is in actual motion. 

Food — carnivorous habits 

The snails which I have kept in confinement for three years 
have been fed on apples and lettuce, and occasionally cabbage. 
At first I placed lettuce in the box, but they refused to eat it. 
After several days I placed pieces of apple in the box, and these 
they ate ravenously. I fed them on apples for a month or more, 
when they seemed to tire of them and refused to eat. After a 
little time I placed lettuce in the box; this they ate, and since 
that time it has been their principal food. 


The popular belief that snails will feed on almost any vegetable 
is erroneous. I find that they are very particular regarding their 
food. I have placed spinach, young beet leaves and several other 
kinds of tender vegetables in the box, but they have refused to 
eat them. 

Binney speaks of the carnivorous habits of Circinaria 
c n c a V a, and also speaks of Polygyra sayi devouring 
its own species. John Walton, in Mollusca of Monroe county, says 
of the cannibalistic habit, in some of the species: " I had abun- 
dant evidence the past summer in the Zonites fuliginosa; 
fully one third of the specimens of this species, taken during a 
special search by myself and pupils, were found devouring shells 
and animals, sometimes their own species, but more frequently 
the young of P. a 1 b o 1 a b r i s, t h y r o i d e s, sayi, and T r i- 
odopsis palliata. This was in July, and possibly the time 
of the year had something to do with the habit, as in the case of 
some seed-eating birds that are known to consume large quanti- 
ties of insects in feeding their young and probably themselves 
during the breeding season ". 

I would suggest, in regard to their carnivorous habits, that, if 
the season was very dry, there may have been a scarcity of suit- 
able vegetable food. I have raised over sis hundred specimens 
from the egg, and I have found that, when the adult animals were 
plentifully supplied with food, the eggs and young were per- 
fectly safe. When returning from my vacation, I packed 
many specimens of P. al b ol ab ri s in a box of dead leaves; 
in a small box I had several hundred eggs and very small young. 
Several days elapsed before I could attend to them. I then pro- 
cured a box, placing several inches of earth in the box, covering 
it with dead leaves, and placed the larger shells on the leaves. 
Then I busied myself with the eggs. Some that were just hatch- 
ing, partly out of the shell, I reserved to put in alcohol. The 
others I laid temporarily on a piece of paper in the box with the 
larger shells. After putting the specimens in alcohol I returned 
to the box, and was surprised to see several of the adults busily 


engaged in devouring the eggs; but I attributed tMs to the fact 
that many of the specimens, procured by me at the St Lawrence 
river, owing to the exceedingly dry season, had been without food 
for several weeks. I very much doubt that they are ever car- 
nivorous when furnished with an abundance of vegetable food. 
The immunity of the eggs and young in a box with more than a 
hundred adult specimens would seem to prove this. 

Since the above observations were made two years have 
elapsed, and during that time I have raised many species, both of 
P o 1 y g y r a and L i m a x , from the egg to maturity and have 
noticed no carnivorous habits, though some of the smaller forms 
of L i m a X and Polygyra have been raised in the same box 
as the large Limax maxima s, and some of the latter had 
a length of 4 inches. In the same manner the smaller species of 
Polygyra have been safely raised with P. a 1 b o 1 a b r i s . 
The newly hatched young fed principally on the softer parts of 
the dead leaves in the box, skeletonizing them. 

I do not know the exact time elapsing between the laying and 
the hatching of the egg, but it is certainly less than three weeks. 
When on a visit to the St Lawrence river in August, I collected 
several specimens and placed them in a box with moist earth 
covered by dead leaves. When, three weeks afterward, I took 
the specimens from' the box, I found several groups of eggs, in 
two of which the young were just emerging from the shell. 

There seems to be no uniform time for the laying of the eggs. 
I have had a large number of specimens in captivity for three 
years, and at almost any time eggs and newly hatched young 
could be found in the box. In some specimens collected in the 
winter, while hibernating, well developed eggs were found in the 
uterine canal. 

Digestive system 

The mouth is situated in the anterior part of the foot, and is 
bounded by thick, fleshy lips (pi. 5, fig. 1). These lips are divided 
into the upper, lower and lateral. The upper lip is composed of 
five lobes or divisions situated side by side. The lower lip has 


four divisions, of which the two lesser are situated above the two 
larger divisions. The lateral lips are each entire, comparatively 
large and somewhat crescentiform. 

The mouth leads into an organ known as the buccal body (pi. 
4, fig. 1). This organ is somewhat irregularly oval-shaped, and 
contains the masticatory qrgan known as the radula (pi. 4, fig. 3). 

Just within the upper lip is the crescentiform, corneous lamina, 
known as the " jaw " (pi. 5, fig. 2), reddish brown in color, and 
occupying the position of an upper jaw. On the outer face of the 
jaw are 12 vertical ridges, with pointed ends, which project be- 
yond the lamina. The ridges with their pointed ends closely 
resemble teeth. The jaw is attached to the buccal body by a 
band of muscular fibers, inserted in its upper convex edge. Dur- 
ing feeding the jaw projects beyond the lips, which are protruded, 
having the appearance of a prehensile proboscis, which takes 
hold of the food and draws it to the mouth, the jaw cutting it into 
small pieces, acting as a chopping knife. 

The food now passes into the buccal body. A reference to the 
figures on plate 4 will give a clear idea of the structure of that 
organ. The outer walls are thick and are composed of constrictor 
muscular fibers. On the floor of this organ are two gristly ele- 
vations, known as the odontophoral cartilages, which have, at- 
tached to their lower parts, small muscles arising from the side 
walls of the buccal body. Besting on the odontophoral cartilages 
is a cushion-shaped elevation, inclosed in a mucous membrane, 
known as the odontophore. Overlying this is the lingual ribbon, 
or radula, which is studded with an immense number, some fifteen 
thousand, of small teeth or denticles, arranged in transverse and 
longitudinal rows. 

The teeth preserve the same form throughout in a longitudinal 
line. The central line always differs from the others, and they 
gradually vary in form and size, as they pass from the central 
line laterally. The radula, or lingual ribbon, takes its origin in 
the sac of the radula (pi. 4, fig. 3, 4), which projects from the 
lower posterior part of the buccal body, continuing anteriorly 
from the radular sac upward to the dorsal part of the buccal body, 


then curving downward. It is connected by muscles with the 
floor of the buccal body. Within the sac of the radula and im- 
mediately anterior to it, the teeth are immature, in the posterior 
part of the sac consisting of very minute papilla-like elevations, 
each arising from a single cell. At the central part of the radula 
the teeth or denticles are fully developed. Anteriorly they are 
worn down, in some cases becoming smooth. During feeding the 
radula is moved forward and backward by the action of the 
muscles, acting as a rasp to triturate the food. 

In addition to the muscles already mentioned, the foUbwing 
muscles are connected with the buccal body (pi. 4, fig. 4, IJi) : the 
buccal retractors, which have their origin, in common with the 
tentacular muscles and the retractor muscles of the foot, at the 
columella, and are inserted, as wide bands, in the posterobasal 
and the posterolateral parts of the buccal body. Numerous small 
muscles proceed from the buccal body to the integument of the 
lips (pi. 4, fig. 1, 9). There are two delicate muscles proceeding 
from the sides of the buccal body (pi. 4, fig. 1, 8), which, passing 
forward and downward, are inserted in the cephalic integument. 
Two broader bands of muscles, arising from the base of the buccal 
body, below the muscles just mentioned, proceed laterally, and 
are inserted in the integument (pi. 4, fig. 1, 7). A pair of very 
delicate muscles arise from the posterolateral part of the buccal 
body, and, passing along its sides, are inserted in the cephalic 
integument (pi. 4, fig. 1, 6). 

The esophagus takes its origin in the dorsal -posterior part of the 
buccal body, and consists of a tube passing straight back between 
the supra and infra-esophageal ganglia (pi. 4, fig. 1, 2, 4), the com- 
missural cords connecting the ganglia bounding it. The eso- 
phagus dilates and forms what is known as the crop. The mem- 
brane of the esophagus, as well as that of the crop, is very thin, 
and consists of a columnar epithelium and a basement membrane. 

The columnar cells of the epithelium are long and pyramidal, 
broad at the base and very narrow at their attached parts. They 
are filled with fine, granular matter, and have each a nucleolated 
nucleus. Internally there are longitudinal folds of the membrane. 



The crop is elongate oval (pi. 5, fig. 3, 4), having a diameter 
three or four times that of the esophagus. Exteriorly it has a 
somewhat plicated appearance, caused by the longitudinal folds 
of the interior. It is situated in the first volution alongside of a 
part of the spermatic duct. 

On each side of the crop are situated the salivary glands (pi. 5, 
fig. 3, 4). They are elongate, somewhat oval, and arborescent in 
appearance. They extend nearly the entire length of the crop. 
They are white in color, and under the magnifying glass present a 
beautiful appearance. They are composed of lobules, which are 
the dilated beginnings of the ducts, lined with cells oval in form 
and having a nucleolated nucleus. The glands are connected 
with the mouth by ducts, which extend alongside the esophagus. 
They are cylindric and conspicuous (pi. 5, fig. 3).^ 

The stomach begins almost immediately at the termination of 
the crop (pi. 5, fig. 3). At first it is small, but little greater in 
diameter than the esophagus, but rapidly and regularly increases 
in size nearly to its extremity. A transverse section is circular 
in outline. The anterior part is situated in the first volution of 
the shell, lying alongside the spermatic duct, continuing, having 
on one side the larger lobe of the digestive gland, and the 
albumen gland, on the other side being in contact with the herm- 
aphroditic duct. It continues to the superior or smaller end of 
the digestive gland and ovotestis, where it bends somewhat 
abruptly downward and backward, giving origin to the intestine. 
Its walls are apparently striated and very thin. The contents of 
the stomach can be seen through the walls. For illustrations of 
the crop and intestines see plates 5, 6, 10 and 14. 

The intestine is of about the same diameter as the esophagus. 
Immediately on leaving the stomach, it turns backward below 
the stomach to the large lobe of the digestive gland, following the 

1 According to A. B. Griffiths {F/iys. invert, p. 109), the following constituents are 
found in the salivary secretions : soluble diastatic ferment, capable of converting starch 
into glucose, calcium, chlorin and doubtfully sulfocyanates and calcium phosphates. In 
the branchiate Gasteropoda the latter two substances occur, as well as mucin, but 
doubtfully chlorin. 


lateral and posterior border of that gland, then, turning, it pro- 
ceeds forward and downward on the outer part of the digestive 
gland, approa'ching very closely to the first part of the intestine 
at a short distance from the stomach; then, turning, it proceeds 
upward and backward through the digestive gland to the border 
of the pulmonary sac. In its course through the digestive gland 
it forms an exaggerated letter S (pi. 5, fig. 3; pi. 6, fig. 7, 8). 

The rectum continues along the border of the pulmonary sac 
to the anus, which is situated near the respiratory orifice (pi. 5, 
fig. 3, 8). On the outer side of the rectum, running its entire 
length, is a band of muscular fibers, the function of which is, prob- 
ably, to shorten the rectum and to assist in expelling its contents. 

The digestive gland (pi. 5, fig. 3, 9), was formerly regarded as 
analogous to the liver of vertebrate animals, but the organ con- 
tains a diastatic ferment, which converts starchy matters into 
glucose, and is comparable to the pancreas in vertebrate animals. 
It contains neither bildary pigments nor biliary acids. The liver 
of vertebrate animals is not a digestive gland in the true sense of 
the word, since'neither the bile nor an infusion of the hepatic 
tissues contains a digestive ferment. The name liver could not 
therefore be appropriately applied to the digestive gland of the 

The digestive gland is divided into two parts, the larger and 
inferior of which occupies the outer part of the volution imme- 
diately beyond the heart and renal organ. The smaller and 
superior lobe, in conjunction with the ovotestis, occupies the 
apical whorls beyond the stomach. 

In the digestive gland are innumerable ducts which unite 
and form a large duct in each lobe of the gland, the three large 
ducts uniting in one, which, in connection with the duct from the 
superior lobe of the gland, enters the stomach at a short distance 
from the beginning of the intestine. 

The digestive gland is composed of lobules, which are formed 
by the enlarged commencements of the ducts, and are lined with 



polygonal cells, which become rounded on the removal of 

Pedal gland 

The pedal gland (pi. 4, fig. 4, 5), is situated in the middle of the 
basal part of the foot. It is a spongy-appearing mass, extending 
about two thirds the entire length of the foot, with a central cir- 
cular passage connecting with the exterior by an opening im- 
mediately below the mouth, and sending forth numerous ducts to 
all parts of the basal portion of the foot. Its office is to secrete 
the mucus or slime, which the snail so abundantly exudes while 
moving, and which when hardened by the air presents a glassy 

' enterochlorophyll 
oleic acid 
fatty acids 

In the alcoholic extract 



In the ethereal extract, 

ash / phosphoric acid 
' sulfuric acid 
a trace of fat 

globules (coagulating at 66^ C.) 

' potassium 
ashi iron (traces) 

phosphoric acid 
. sulfuric acid 

Dr Griffith {Phys. invert, p. 115) names the following substances as being found in 
the digestive gland of the Pulmogasteropoda : diastatic ferments, pancreatin, peptones 
and sodium. 

In the aqueous extract 

iDr Levy (^Zeit. biol. 27:398) has separated the following substances from the 
digestive glands of Helix pomatia. 


Generative system 
Plates 7, 8 

The Helicidae and Limacidae are hermaphroditic, and 
the hermaphroditism is most complete, having complex male and 
female organs separated from each other, but so arranged that 
self-impregnation is impossible, the union of two animals being 
necessary to reproduction. 

The generative organs consist of the penis, vas deferens, sper- 
matic duct, oviduct, uterine canal, albumen gland, hermaphroditic 
duct, consisting of the fallopian tube and spermatic duct, and the 
ovotestis. On the right side of the foot, about on a line with the 
beginning of the superior tentacles, is an orifice known as the 
genital orifice. It presents the appearance of a short slit with 
the margins in contact, but is capable of great distension. It is 
from this orifice that the penis is protruded during coition, and 
into which the penis of the other animal is inserted. Leading 
from this orifice is a short chamber or tube, known as the cloaca, 
atrium, or genital vestibule, connecting with the penis and 
vagina. The orifices of these two organs are situated side by side, 
that of the penis immediately in front of the vagina. 

The penis is a long, cylindric body of a glistening white color, 
occupying the dorsal anterior part of the foot, nearly straight, 
very slightly curved. Its walls are strong, thick and composed 
of muscular fibers. At the base of the penis the walls are very 
much thickened, and abruptly turned back exteriorly (pi. 8, fig. 
1, 2). The inner surface of the walls is plicated (pi. 8, fig. 3). The 
lining membrane along the bottom of the penis is elevated into a 
very strong muscular fold (the "pilaster"), nearly filling the 
interior of the penis (pi. 8, fig. 3). The plications of the inner sur- 
face of the walls are surmounted by papillae (pi. 8, fig. 4). The 
plications of the lining membrane of the penis, and the muscular 
fold as seen in the penis laid open longitudinally, and in the trans- 
verse sections, under a low magnifying power or hand lens present 
a very beautiful appearance. 

The vagina and the spermatheca or receptaculum seminis are 


connected with the genital vestibule, the origin of the vagina be- 
ing immediately posterior to that of the penis. The vaginal body 
is cylindrically oval in form, having a length of from two and one 
half to three times the diameter. The walls of the vagina are 
strong, thick, and consist of muscular fibers. Internally there 
are a number of strong regular, longitudinal muscular elevations, 
covered by a double membrane. Near the base these folds are pli- 
cated, but become smooth above. At its extremity the vagina nar- 
rows into a thin-walled tube or duct, which is of varying length, 
sometimes short, at other times as long as the vagina. This 
duct becomes dilated above, forming the receptaculum seminis. 
The latter organ is elongate oval in form, having very thin walls, 
and with minute longitudinal folds along the interior (pi. 8, fig. 
10, 11, 14). These folds sometimes give a striated appearance to 
the exterior. The organ is in contact with and closely adhering 
to the oviduct. 

During coition the penis is inserted in the vagina, and is there 
closely held by the muscular walls and longitudinal folds, the 
spermatozoa finding their way into the receptaculum seminis, 
afterward passing down through the vagina, and fertilizing the 
egg as it leaves the oviduct. 

In addition to being a receptacle for the spermatozoa, the 
receptaculum seminis, according to Dr Leidy^ " secretes a mucoid 
matter, which probably facilitates the passage of the ova through 
the cloaca. The mucus matter in the bladder is frequently found 
to contain an immense number of an infusorial parasite, which I 
have described under the name C r y p t o i c u e. " ^ 

Dr Leidy's description is given at the end of the article on the 
generative organs. 

Ovotestis. The ovotestis, in common with the superior organ 
of the digestive gland, occupies the apical volutions of the ani- 
mal (pi. 7, fig. 1, 12). It is lighter in appearance than the digestive 
gland, and is composed of a number of bundles or fasciculi of 
short ceca. Each fasciculus is composed of numerous ceca, is 

1 Terrestrial moll, and shells of the United States, p. 234. 

2 Tour. acad. nat. sci. new series, v. i. 


broadly pointed at the base, rapidly expanding, circular and con- 
vex at the opposite extremity, having very much the appearance 
of a composite flower. The ceca are sometimes simple, but usu- 
ally bifurcate or trifurcate. The ceca of each fasiculus connect 
with a tube, which in turn connects with a duct leading into the 
hermaphroditic duct. Each cecum seems to have four walls, form- 
ing an inner and outer chamber (pi. 7, fig. 7), a tube within a 
tube. In the outer chamber or tube are produced the ova and 
in the inner, the spermatozoa. ' 

The hermaphroditic duct leads from the ovotestis to the uterus 
and penis. It is an extremely convoluted organ, so twisted and 
confused in P. albolabris as apparently to be composed of 
short, cylindric, contorted tubes, agglutinated together. In 
some other species of Helicidae and in L i m a x it is more 
nearly straight, being flexuous, sometimes slightly folded or 
spiral, but not convoluted. This duct is invaginated in the same 
manner as the ovotestes, the outer tube carrying the ova and the 
inner the spermatozoa. 

Just before reaching the albumen gland the hermaphroditic 
duct becomes constricted into a delicate thread-like tube. It 
then enters an accessory gland, which is somewhat the form of a 
cornucopia, the large end of which is composed of several folli- 
cles. The gland rapidly narrows to its opposite extremity. It 
is partially imbedded in the substance of the albumen gland. 
Its purpose has not been clearly determined, though from the 
size and persistency it is undoubtedly important. At the small 
extremity of the gland the male and female organs become sepa- 
rated, the fallopian tubes passing into the uterine canal, and 
the epididymis continuing as a spermatic duct on one side of 
the uterine canal (pi. 7, flg. 1, 9, and pi. 14, 22). 

Albumen gland. The albumen gland, which is situated at the 
extremity of the uterine canal, is a large boat-shaped or lingui- 
form gland, of a yellowish color (pi. 7, fig. 1, IJf). The walls of 
the gland are composed of cells filled with albumen. The interior 
of the gland is hollowed out by an elongate chamber or duct. The 
function of the organ is to supply the ova with albumen. 



The spermatic duct, as it proceeds along the uterine canal, is in- 
vested with a yellowish mass, which has been called the prostate 
gland. In structure it is composed of very closely packed, sim- 
ple, tubular follicles, which are lined with pyramidal, epithelial 
cells, containing at their base a nucleolated nucleus. 

At the termination of the uterine canal the male and female 
organs become entirely separated, forming the vas deferens and 
the free oviduct (pi. 7, fig. 1, 6, 7, and pi. 14, fig. 1, 18, 19). The 
vas deferens becomes enlarged, and for some distance assumes 
a spiral or twisted form; it then contracts, becoming a long, 
simple tube, somewhat folded on itself, in order to adapt itself 
to the restricted space which it occupies. It continues to the 
extremity of the penis, the walls of which are very thick and 
muscular. The interior passage or duct is, for the greater part 
of its length, trilobate in section. As it enters the penis it is 
somewhat enlarged and the orifice is plicated. It is surrounded 
by thickened lips and folds, which project into the penis. This 
fold has a plicated membrane (pi. 8, fig. 6), resembling the mem- 
brane of the fold of the penis previously described, and the outer 
part is nearly in contact with that fold. 

The urethra is situated between the lining membrane of the 
penis and the membrane of the muscular fold (pi. 8, fig. 2). 

The retractor muscle of the penis is inserted in the vas deferens 
at a short distance from the end of the penis (pi. 14, fig. 1, 11). 

Uterine canal. The uterine canal is a large long tube or canal, 
with plicated or sacculated folds. It is much greater in diameter 
than the accompanying prostate gland. The walls are mostly 
composed of polygonal cells, each cell having several nuclei 
(pi. 7, fig. 1, 8 and pi. 14, fig. 1, 21). It is within this organ that 
the eggs are completed. 

Oviduct. The oviduct (pi. 7, fig. 1, 7, pi. 14, fig. 1, 20) is about 
the same size as the twisted part of the vas deferens, and con- 
tinues from the uterine canal to the vagina, entering that organ 
near its mouth. 

During coition the penis is everted, passing out of the genital 
orifice, and entering the vagina of the second animal, coition con- 
tinuing for several hours. 


The position of the generative organs in the animal can be 
clearly understood from plate 23, figure 9. 

The penis occupies the dorsal anterior part of the foot; the 
vagina the anterior right lateral part. The receptaculum seminis 
closely adheres to the prostate gland. The vas deferens is situ- 
ated between and beneath the penis and vagiua; on account of its 
great length being disposed in irregular folds. The prostate 
gland and uterine canal enter the first volution of the animal and 
are disposed alongside the pulmonary cavity. The albumen 
gland lies between the large lobe of the digestive gland and the 
stomach. The constricted, thread-like part of the hermaphroditic 
duct crosses the stomach from the base of the albumen gland, 
and the convoluted part of the duct lies in the inner margin of the 
volution, alongside of a part of the stomach. The ovotestis, in 
conjunction with the superior lobe of the digestive gland, occu- 
pies all the apical parts of the animal. 

The generative organs of the other species of helicoid snails, 
though varying in detail, are suificiently similar to those of 
P. albolabris to enable the student to recognize them with- 
out difficulty, with the exception of those of Gastrodonta 
intertexta, G. gularis, G. ligera and G. s u p- 
p r e s s a, which species have accessory organs, that will be de- 
scribed later on. 

The vas deferens is usually about twice the length of the penis, 
or less. InPolygyra exoleta it is longer^ but in no 
species, as far as I am aware, is it as long as in P. a i b o 1 a b r i s. 
InP. tridentata and in P. e x o 1 e t a it has the same form as 
in P. albolabris, that is^ enlarged, glandular, annulated or 
somewhat spiral in appearance at its beginning; while, on the 
contrary^ inPyramidula solitaria it has this form at its 
termination. In O m p h a 1 i n a f u 1 i g i n o s a it is for a great 
part of its length expanded, so that its diameter is equal to that of 
the penis. 

In some species, as in Polygyra auriculata and 
P. s a y i, the penis is very long and bent on itself, while in others, 
as Pyramidula solitaria, it is short, stout and clavate. 


InPolygyra profunda the base of the penis is included 
in a sheath formed by a continuation of a part of the genital 
chamber, in the form of an inverted cone. In Circinaria 
c n c a V a it is long and cleft or bipartite at the summit. 

The lining membrane usually has a number of rugae, longitudi- 
nal and oblique. Sometimes^ as in P. a 1 b o 1 a b r i s and P y r a- 
midula alternata, there is one very large fold. In many 
species, as in P. a 1 b o 1 a b r i s, the surface of the membrane is 
papillated, but in some others it is smooth. 

The vagina and receptaculum seminis vary in form. In the 
greater number of species the vagina is not as large and muscular 
as in P. a 1 b 1 a b r i s, and the duct leading to the receptaculum 
seminis is generally longer. 

In Helix aspera and other European species there are 
several accessory organs not found in P. a 1 b o 1 a b r i s or In 
L i m a X. They are the flagellum^ the dart sac and the accessory 
mucous or digitate glands. 

The flagellum is an elongated diverticulum of the penis and is 
much coiled. The dart sac is an elongated, clavate, appendage 
from the base of the oviduct. It has powerful muscular walls, 
and contains in its interior the dart or spiculum amoris, attached 
to a nipple-like protuberance at the bottom of the sac. The dart is 
four-bladed, calcareous, and growing by the addition of calcare- 
ous particles,, deposited at its base from the vascular protuberance 
to which it is affixed. If broken off it is speedily renewed in like 
manner. Before coition the dart sac is everted from the genital 
orifice, the dart thus becoming exposed. It is probably an excita- 
tory organ. 

The mucous or digitate glands, according to T. Eymer Jones, 
" consist of a series of branched ceca, derived from two excretory 
ducts, by which a milky fluid, secreted by the ceca, is poured into 
the egg passage prior to its termination ". , 

The receptaculum seminis of Helix aspera differs 
greatly from that of P. a 1 b o 1 a b r i s and Li max maxi- 
m u s, consisting of an elongated duct, which subdivides into two 


cecal diverticula, a longer and stouter coiled one, and a shorter 
one with globular head, which during life is concealed in the first 
coil of the intestine. 

It is a remarkable fact that, while the flagellate form of the 
penis, and the accessory organs, viz, the dart sac and multifld 
vesicles, are very common in European species of Helix, they 
are very rare in east American forms. A flagellate form of the 
penis does not exist in a single one of the latter forms. An 
analogue of the multifid vesicles exists in only four of the species 
occurring in New York. In G-astrodonta intertexta 
and (J. g u 1 a r i s there is a single pair of follicles. In G. 1 i g e r a 
and G. suppressa there is but one short follicle. The dart 
sac exists in the above-named species. 

Description of a new species of entozoa 


Plate 13, fig. 6 

In September 1846 I first gave an account in our proceedings 
of a new genus and new species of Entozoa, inhabiting the fluid 
contained in the spermatheca of Helix albolabris, H. tri- 
dent a 1 i s and H. alternata. Since then I have verified 
the observation, and also have detected it in other species of 
Helix, viz, e 1 e v a t a and t h y r o i d e s, and have also de- 
tected it in an allied genus, Bulimus decollatus. The 
name which I gave it at that time I was not awaye had been pre- 
viously applied to a genus of Insecta brachelytra, with 
the only difference of the latter having a neuter termination. I 
will therefore change the name. 

Cryptoicus minutissimus; forma mutabilissima; organisatione interno cellu- 
larium et granulosum, C. h e 1 i c i s. Coloris expers; forma plerumque elongata, f usiforme, 
vel ovata ; caudis duabus adversis, una longior quam altera. Structura interno sto- 
machos duos et granules numerosus parvos ^exhibit. Long y-l-E- — . ^ . lin. Habitat 
in spermatheca Helices albolabris, tridentata et Bulimus decollatus. 

This singular entozoon is a polygastric animalcule. Its varied 
forms and movements are curious to observe; at one moment glo- 
bulose, then oval, ovate, fusiform, sigmoid, crescentic, etc. It 
appears as if it would outvie the kaleidoscope in its changes. 
Sometimes it collects in bunches, adhering by the end of the 
Cauda to each other, and frequently it may be observed to contract 
upon either of the large cellules, causing them to project beyond 


the outline of the animal. The motions are vibratile rotary, with 
a lateral progression, or whirling in circles like the insect G y r i- 
nus. Cryptoicus from its position might be mistaken for 
the spermatozoa of the animal, but may be readily distinguished; 
the spermatozoa of Helices having either a uniform sigmoid 
or a spiral body, with an enormous proportionate length of tail, 
and a slow vibratile motion. 

Plate 13, figure 6, represents some of the varied forms of the 
animal highly magnified. 

Circulatory system 

Method of injecting the blood vessels. I have found the follow- 
ing method to be the best in obtaining a complete injection of the 
circulatory system, and by it I have obtained the most beautiful 
results, plainly showing all the minute ramifications of the arter- 
ies and veins. 

The necessary materials are an ordinary hypodermic syringe, 
with as fine a needle as it is possible to obtain, the finer the bet- 
ter; as an injection which would not pass through the finest 
hypodermic needle certainly would not pass through the fine ar- 
teries and veins. The distal extremity of this needle should be 
blunt or slightly bulbous. A curved sewing-needle and very fine 
thread are also necessary. As an injection fluid I have used and 
found perfectly satisfactory Dr Seller's carmine gelatin. This is 
sold by the ounce and comes in a solid mass. 

A day or two before making the injection, some of the gelatin 
should be placed in cold water in a wide-mouthed bottle. The 
water will soften the gelatin. When it is proposed to use the 
injection, the bottle can be set in a pan of hot water. Within 
a short time the gelatin will be completely dissolved. It should 
be thin enough when hot to enter easily the arteries and veins, 
but of sufflicient consistency to harden when cold. No rule can 
be given as to the exact proportion of water and gelatin. The 
right degree of fluidity must be determined by each student. Use 
only filtered water with the gelatin, as a small particle of dirt in 
the water might prevent a successful result. 

Take the animal as soon after death as possible; wash away 
the mucus. Then, as previously described, remove the shell, 


wholly or till the heart can be plainly seen. The latter method 
is, I think, preferable, as it aToids the danger of rupturing some 
of the blood vessels, as sometimes happens when the entire shell 
is removed. Cut through the peritoneum, alongside the rectum, 
taking care not to injure the large vein which accompanies the 
rectum; turn back the walls of the pulmonary cavity till the 
heart is exposed. Using the curved needle pass a thread under 
the ventricle. Place the animal in warm water, as hot as can 
be comfortably borne by the hand, and before injecting be cer- 
tain that the animal is thoroughly warmed through; also place 
the syringe in hot water, having both the syringe and injecting 
fluid warm. Draw some of the fluid into the syringe; then, hold- 
ing the needle upward, expel a drop or two of the fluid, so as to 
be certain that no air remains in the syringe. Leaving the animal 
in warm water, with the point of an extremely sharp scalpel 
make a slight incision in the walls of the ventricle just large 
enough for the point of the needle to enter. Insert the needle, 
bring the two ends of the thread together and tie them just back 
of the point of the needle, to guard against the escape of the 
injection through the incision. Some assistance would be useful 
in this operation, as one hand will be occupied with the syringe. 
Gently press the piston, slowly injecting the fluid, stopping im- 
mediately when the injection is complete, as much pressure will 
rupture the walls of the blood vessels. 

f^ometimes a very flne injection of the arteries can be made 
by merely inserting the point of a hypodermic needle in the ven- 
tricle, the rest of the process being as described above. But the 
injection is liable to escape where the needle enters the wall of 
the ventricle. 

The injecting is a very delicate process, and partial, or even 
a complete failure at the first attempt should not discourage the 
student. The most frequent cause of failure is in not keeping the 
animal and syringe warm enough, the injecting fluid rapidly hard- 
ening in the blood vessels, preventing their full injection. 

When the animal is fully injected, place it at once in cold 
water; this rapidly hardens the gelatin. The remainder of the 


shell can now be removed and the animal immediately dissected, 
or it can be placed in alcohol for future use. The alcohol must 
be at first very weak, gradually increasing its strength each day. 

The advantage of a gelatin injection over a fluid one is that, 
as the gelatin becomes hardened, dissections can be made with- 
out danger of the escape of the injection from the severed blood 
vessels. As the injection is a brilliant carmine, the blood vessels 
stand out in bold relief from the light background of the various 

Heart. The heart (pi. 9, ], pi. 10, fig. 1, pi. 14, fig. 1, 30, 
32) is situated in the outer portion of the first volution, just ante- 
rior to the peristome, and is plainly visible from the exterior. Its 
pulsations can be observed even through the shell. Ordinarily the 
pulsations number about 45 or 50 a minute, in an adult indi- 
vidual ; but are variable, sometimes being much faster, and during 
hibernation slower. In a young individual the pulsations seem to 
be much faster, sometimes equaling 150 a minute. The heart con- 
sists of a single auricle and ventricle, inclosed in an oval pericar- 
diac sac. The ventricle and auricle are pyriform, placed base to 
base, the bases being somewhat truncated. The ventricle is about 
twice the size of the auricle. 

In composition the walls consist of unstriped muscular fibers, 
granulated, showing oval nuclei on the application of acetic acid. 

The interior of the heart is lined with tesselated epithelium, 
consisting of granulated cells. The interior of the walls of the 
aorta have a similar structure. 

The wall of the pericardium is very thin and transparent. The 
pericardial fluid is very abundant, and, according to Dr 
Leidy, is sometimes inhabited by an entozoon, named by him 
Distoma vaga ns.^ Between the auricle and ventricle is a 
valve, so disposed as to permit the passage of the blood only from 
the auricle to the ventricle. 

Arteries (pi. 9, flg. 1). The ajK'x of thi' ventricle givt's origin 
to one large aorta, which almost immediately subdivides, one 
branch proceeding posteriorly, and supplying the digestive gland, 

ijonr. acad. nat. sci. new series, v. i Philadelphia. 


hermaphroditic duct, stomach, ovotestis and albumen gland; the 
other and larger of the two proceeds anteriorly, supplying the 
remaining organs of generation, muscles, crop and all the organs 
contained in the foot. 

The posterior aorta passes on the outer part of the inferior lobe 
of the digestive gland, giving off numerous branches to this gland, 
the intestine and also to the albumen gland. Just after giving off 
this latter branch, it crosses a portion of the stomach, and for a 
short distance disappears in the substance of the lobe of the diges- 
tive gland; then emerging it continues along the lower inside edge 
of the volution to the apex of the animal, giving off branches to 
the superior lobe of the digestive gland, and to each of the fasci- 
culi of ceca composing the ovotestis. 

The anterior aorta, at a short distance from the heart, gives off 
a branch to the stomach. On the stomach this branch subdivides 
into two branches; each of which gives off numerous branches, 
covering the stomach with their ramifications. This artery, before 
reaching the stomach, gives off a branch, which continues to the 
hermaphroditic duct. 

At a short distance from the branch to the stomach is a large 
branch, which continues on the surface of the prostate gland and 
uterine canal, giving off numerous small branches to these organs. 

At a short distance beyond this branch is another, which shortly 
subdivides; the larger of the two divisions continuing to the mus- 
cular collar, and supplying blood to it, and to the adjacent parts. 
The smaller of the two divisions continues with the retractor mus- 
cles of the foot. From the larger of the two subdivisions a branch 
is given off, which continues to the crop, supplying the crop and 
the overlying salivary glands. A small branch continues with 
each salivary duct to the buccal body. 

The main aorta continues, without branching, to the infra- 
esophageal ganglia, where it suddenly turns downward and back- 
ward, continuing posteriorly in the base of the foot. Just at 
the turn it gives off three branches, which proceed directly 
anteriorly; the central and largest of which supplies the buccal 
body. The two lateral ones, which are very minute, proceed 


to the cephalic integument. A branch is also given off, which 
proceeds alongside the nerve to the muscular collar. Branches 
also accompany the commissural cord, forming a complete 
circle. From this, on the left side, arteries proceed to the 
tentacles; from the right side an artery proceeds, which subdi- 
vides; one branch proceeding to the penis, the other to the vagina; 
Ihese organs being covered by numerous ramifications. From the 
artery near the ganglia proceed the arteries supplying the ten- 
tacles of the right side. 

Veins. The arteries break up into smaller and smaller branches, 
and finally into a network of capillaries, that meet a similar net- 
work leading to the veins, which empty into large veins or sinuses; 
the principal ones of which are three in num'ber. The first begins 
in the apex of the volutions, receiving the veins from the superior 
lobe of the digestive gland, continuing on the outer edge of the 
volution to the beginning of the pulmonary chamber, receiving in 
its course several large veins. These divide, one division passing 
along the edge of the pulmonary chamber, alongside the rectum 
to the thickened muscular collar, passing along the inner edge 
of this to the base of the pulmonary chamber. The other division 
passes along the base of the pulmonary chamber, uniting with the 
first described division at the muscular collar, forming a sinus 
completely incircling the pulmonary chamber, and known as the 
circulus venosus pulmonis, or pulmonary circulus. 

The arteries of the foot, as in the visceral part of the body, break 
up into capillaries, that enter the capillaries of the veins, which 
empty into a large vein or sinus, situated below the pedal gland. 
From this sinus proceed numerous veins, which finally connect 
with the pulmonary circulus. 

From the pulmonary circulus arise many veins, which form a 
large vein leading to the heart, and known as the pulmonary vein. 
These veins are known as the efferent veins. They alternate with 
much regularity with a series of veins leading from the pulmonary 
vein, but intimately connected with the efferent vessels, which are 
known as the afferent veins (pi. 11, fig. 1-4). 

Circulation. The circulation is as follows: the blood leaves 


the heart hy the aorta, and is distributed by the arteries to the 
different parts of the body, and passes from the minute branches 
of the arteries into a flexus of capillaries spreading over the 
whole body; passing from them into the veins, and from the veins 
into the sinuses previously described; finally all the blood enter- 
ing the pulmonary circulus; and thence the pulmonary veins, 
where, circulating freely through efferent and afferent vessels, it 
becomes thoroughly aerated. 

The renal organ or kidney is supplied with blood, which has 
previously been aerated, hut only a small part of the blood 
passes each time through it. 

Though the veins are situated in the substance of the body, 
and their walls are much thinner than those of the arteries, they 
are not simply lacunae or wall-less passages in the body, as they 
have frequently been described. The walls though thin are dis- 

Blood. In animals of the simplest structure all the fluids seem 
to be of the same nature and seem to be '' only water charged 
with organic particles, but in animals higher in the scale of 
being the fluids cease to be of the same nature, and there is one^ 
distinct from all others, destined to nourish the body. This fluid 
is the blood. It not only nourishes the body, but is the source 
from whence is derived all the other secretions, such as saliva, 
urine, bile, etc." 

In the higher animals the blood is of a red color; but in the 
Invertebrata it is of different densities and of various colors. 

The blood of the Helix and L i m a x consists of a nearly 
transparent fluid in which float solid corpuscles. 

For the following facts in regard to the composition of the 
blood I am indebted to Dr GriflBth's Physiology of the Invertebrata. 

In the majority of the Invertebrata the carrier of oxygen to the 
tissues is haemocyanin, contained in the blood, but in many of the 
Annelida, as well as in nearly all of the vertebrates, the transport 
of oxygen from the surrounding medium (air or water), to the 
living tissues is made by the hemoglobin of the blood. This sub- 
stance, as is well known, forms an oxygenized condition which is 
very unstable, and which is carried by the blood across the tissues 
of the animal, and is there dissolved, yielding its oxygen to those 
tissues which require it. 


In Gasteropoda, as well as in Cephalopoda, Crustacea and 
Arachnida the function of respiration is brought about by an 
albuminoid substance analogous to hemoglobin, but containing 
copper instead of iron, this substance, which Fredericq names 
haemocyanin, forming a. very unstable combination. 

The saline matter contained in the blood of the Helix is 
about 1.075fo; in L i m a x about 1.115;^. 

Touching the color of the blood, Mac Munn^ says in regard to 
the blood of H e 1 i x p o m a t i a : "It assumes a distinct blue tint 
on exposure to 'the air, and gave no absorption bands, but ab- 
sorbed a little of the violet end of the spectrum. On, treatment 
with ammonia its color ^'as not sO' well marked, and it had a 
partially reddish tinge, but no bands oould be seen, and after, 
treatment with acetic acid did not remove the color." 

One time I drowned 12 individuals of P. a 1 b o 1 a b r i s, 
leaving them, as usual, in the water about 48 hours. The blood 
in the arteries of all these specimens had coagulated and turned 
a dark purple black in color, so that the course of the arteries 
could be as distinctly traced as if they had been injected. I am 
unable to account for this phenomenon, as of scores of specimens, 
treated in the same manner, these were the only specimens 
coagulated and colored, though the others were kept in the same 
box and fed on the same kind of food. 

Kervous system 

The nervous system (pi. 12) consists of five distinct sets of 
ganglia, and four ganglionic swellings, and the commissures con- 
necting them or proceeding from them. The principal ganglia 
are the supra-esophageal^ the infra-esophageal, consisting of two 
sets, and the two buccal ganglia. The ganglionic swellings, or 
ganglia, are situated at the extremity of the tentacles. The 
ganglia corresponding to the one situated on the dorsal surface 
of the stomach inLimax maximus I have not observed in 
P 1 y g y r a. 

When the animal is extended, the supra-esophageal ganglia 
are situated just above the esophagus, immediately posterior to 

1 Quart, jour, micro, sci. 1885 


the buccal body, but varying somewhat in position according to 
the degree of contraction of the body. 

The infra-esophageal ganglia are situated below and just pos- 
terior to the buccal body, and are connected with the supra- 
esophageal ganglia by a double commissure. The buccal ganglia 
consist of two small masses, situated just below the surface of 
the posterior dorsal part of the buccal body. They are connected 
with each other and with the supra-esophageal ganglia. 

The esophageal ganglia and the connecting commissures are 
enveloped by an essentially opaque sheath, and it requires very 
careful manipulation to remove this so as to determine the form 
of the ganglia. This is best effected by two small needles fixed in 
the end of small round sticks, as described on page 241, using 
one in each hand. The points of the needles should be inserted 
just below the surface of the sheath, and a little of it torn away 
with each insertion, being very careful not to introduce the .needle 
far enough to penetrate the ganglia beneath. The fine forceps, 
mentioned on page 241, will be found useful in removing the 
loosened parts of the sheath. In this operation it is necessary to 
proceed very slowly. Any undue haste will almost certainly 
result in the destruction of the ganglia. 

The supra-esophageal ganglionic mass, before the removal, of 
the sheath, has the appearance of a single quadrangular mass, 
wider than, long, the posterior margin incurved. The double com- 
missures proceeding from the posterolateral extremities, appear 
as single large, flattened nerves. When the sheath is removed, 
the supra-esophageal ganglionic mass is seen to be composed 
of two sets of ganglia, connected by a commissural cord, the 
ganglia of each set being aggregated together, the two ganglionic 
masses being precisely similar in detail. The principal one of the 
supra-esophageal ganglia (pi. 12, a) is subquadrangular or sub- 
ovate in outline, about two and one half times as long as wide, 
slightly constricted at the middle. Attached to the lower outer 
part of .this ganglion is a smaller ganglion, about one fourth the 
size of the preceding one. Attached to the posterior part of these 
ganglia are three comparatively small, nearly round ganglia (pi. 


12, a), so aggregated as to have, on a superficial examination, the 
appearance of an oblong mass. 

The infra-esophageal ganglia have, before the removal of the 
sheath, the appearance of a flattened, circular mass, v?ith a 
central opening through which passes a large artery. When the 
sheath is removed, it is seen that the ganglia form two masses 
aggregated together, making a sub-circular mass. The upper 
mass is composed of five subovate ganglia, of nearly equal size 
(pi. 12, 6). One is situated dorsally and centrally, and two on 
each side of this one. The lower part consists of two larger ovate 
ganglia, joined to each other and to the ganglia above them. 

The buccal ganglia are small, somewhat kidney-shaped bodies 
(pi. 12, n). 

The ganglia of the superior tentacles are subpalmate in form, 
the palm being unduly developed, and the fingers very short (pi. 
12, e). 

The ganglia of the inferior tentacles are pear-shaped (pi. 12, i). 

The commissures connecting the supra and infra-esophageal 
ganglia are of equal size. The upper commissures proceed from 
the posterior part of the outer supra-esophageal ganglia, and are 
connected with the anterior part of the lower ganglia of the upper 
part of the infra-esophageal ganglionic mass (pi. 12, c). The lower 
commissures proceed from the outer ones of the small, nearly 
round ganglia of the supra-esophageal ganglionic mass, and are 
connected with the lowest two ganglia of the infra-esophageal 
ganglionic mass, or, as they are sometimes designated, the pedal 
ganglia (pi. 12, c). 

From the inner anterior part of the principal supra-esophageal, 
or cerebral ganglia, proceeds a large, conspicuous nerve, which 
connects with the ganglia at the extremity of the superior or ocu- 
lar tentacles (pi. 12, d, e). This nerve, after entering the tentacle 
gives off a nerve which proceeds to the eye, the optic nerve 
(pi. 12, f, g) ; also from the outer anterior part of each ganglia a 
nerve proceeds to the mouth and adjacent integument. 

Prom the central anterior part proceed two very delicate nerves 
which continue to the integument of the superior tentacles. 


From the lateral ganglia of each mass proceed two very con- 
spicuous nerves; the inner one (pi. 12, I), continuing to the mouth, 
the outer one continues anteriorly, branching; one branch (fc) 
going to the mouth and adjacent parts, the other (i), continuing 
to the ganglion at the extremity of the inferior tentacles. 

The nerves previously described give off ibranches to the anterior 
part of the body, also to the penis and vagina. 

From the lower inferior jart of the principal ganglion proceeds 
a commissural cord (o), connecting with the buccal ganglion. 

The anterior extremities of the buccal ganglia are connected by 
a commissural cord. 

From the buccal ganglia nerves pass off: first, two nerves, ante- 
riorly, to the surface structure of the buccal body; second, two 
branches, which penetrate posteriorly into the buccal body; third, 
a branch accompanying the salivary duct to the salivary gland; 
fourth, a branch to the esophagus; fifth, a nerve to the anterior 
part of the buccal body. 

From the infra-esophageal ganglionic mass proceed the follow- 
ing described nerves : from the dorsal ganglion a very conspicuous 
nerve (p), which takes the same general direction as the cephalic 
artery, continuing alongside the uterine canal. At the point where 
ihe arteries give off branches to the muscles and the crop the nerve 
passes through the loop thus formed, and also gives off branches 
both to the muscle and to the crop. It then continues, slightly 
diminished in size, along the uterine canal to the albumen gland. 
The main part continues along the albumen gland; a branch ac- 
companies the hermaphroditic duct to the ovotestis, giving off 
filaments to the stomach and digestive gland. Another branch pro- 
ceeds to the heart and renal organ. From this branch a smaller 
branch proceeds to the adjacent parts of the digestive gland. The 
nerve is easily traced to the digestive gland, but from that point 
the nerves are very fine, and careful study is necessary to distin- 
guish them. 

From each of the two ganglia adjacent to the dorsal one, a very 
large nerve passes to the muscular collar (r); bifurcating just be- 


fore entering the collar, one branch passes through the muscles, 
the other continuing In the pulmonary chamiber. 

Prom the inferior part of the lateral ganglia proceed five nerves 
on each side (u), continuing to the integument. 

From the pedal ganglia proceed two large nerves, running nearly 
directly backward and parallel to the central part of the base of 
the foot, giving off several branches. From the pedal ganglia 
there are about 12 other nerves, supplying the base of the foot. 

The ganglia are composed of cells or gloibules, varying very 
much in size, round or polygonal from mutual pressure, having a 
nucleus which occupies one half or two thirds the globule. The 
nucleus has several transparent nuclei. The nerves consist of 
bundles of tubuli. The walls of the tubuli are transparent. 

Special organs of sense 

Touch. The sense of touch is extremely acute in every part of 
the foot; the integument and base of foot being liberally supplied 
with nerves. The tentacles are specially sensitive, but I have not 
been able to touch any part of the foot so lightly that it was not 
immediateh' felt by the animal. In motion the animal depends 
more on the sense of touch than on eyesight. 

Taste. There is no doubt that the animal possesses some sense 
of taste, but, from long observation, I think that in the selection 
of food the animal depends more on the sense of smell than that 
of taste. 

Light. The eyes of both Helix and L i m a x are situated at 
the extremity of the superior tentacles, and are conspicuous, hav- 
ing the appearance of bright, black specks. Under a low power 
can be seen the globular eyeball invested by a transparent tunic, 
corresponding to the cornea; the crystalline lens lying under the 
delicate cornea; the choroid, which forms two thirds of a sphere, 
transparent and having a single layer of irregularly round or oval, 
black pigment cells. P o 1 y g y r a is nocturnal in its habits, and 
perhaps at that time it can see more clearly; but in all my experi- 
ments with different individuals, many of them conducted with 
only sufficient light to distinguish the animal, I have seen no evi- 


dence that Polygyra is possessed of sight, with the single ex- 
ception that young individuals placed on a table, by a window, 
seemed, to crawl away from the light, but in adult individuals the 
light did not seem to make any difference. I have very frequently 
moved a stick or some bright object directly in front of the ex- 
tended tentacles, as the animal was moving, but with no effect 
whatever. Often I have observed the animal running directly into 
an object, withdrawing its tentacles and changing its course only 
when the tentacles touched the object. 

Smell. That the snail possesses olfactory organs admits no dis- 
pute^ but the location of these organs has been a matter of doubt. 
I have had many snails in captivity for three years, audi I have fre- 
quently experimented with them to determine what degree of 
olfactory sense they possess. After leaving them without food for 
several days, I have put in one corner of the box a small head of 
lettuce, concealing it by a few of the dead leaves. In a short time 
the snails would appear from under the leaves, and on the surface 
would raise the anterior portion of their bodies in the air, with 
extended tentacles, turning from one side to the other, having ex- 
actly the appearance of a quadruped sniflflng the air in the en- 
deavor to locate some object. Having decided on the position of 
the lettuce, they would invariably move directly toward it, and 
this sometimes from a distance of 18 inches. I have repeated this 
experiment again and again but always with the same result. It 
was impossible for the anim'als to see the lettuce on account of the 
screen of leaves, and, as previously asserted, I am satisfied that 
their power of vision is extremely limited, at least by daylight or 
by artificial light. 

The discrimination in regard to food must be due also in a 
great degree to the sense of smell. I have placed in my box of 
snails young beet leaves, spinach and other tender vegetables, 
which it would naturally be supposed would be acceptable to the 
snails; but they invariably refused to eat them, though deprived 
of other foodi, and in no case were these articles even tasted, show- 
ing, I think, that they were rejected on account of their odor. 

It being admitted that they possess olfactory organs, it remains 


to locate them. Dr Leid^^^ and Dr Sochaczewer,^ believed that the 
olfactory organs are situated in the pedal sinus. 

The latter author made the following experiment: 

Having cut off the tentacles of H e 1 i x p o m a t i a, the wound 
was allowed to heal. The snails were then placed on a flat plate, 
the edge of which was smeared with turpentine; both the muti- 
lated and unmutilated specimens turned away from the edges; 
this shows that the tentaculae are not the seat of the olfactory 

I do not think that this experiment is at all conclusive, or in 
fact has any bearing on the matter, as the foot both of Helix 
and of L i m a X is .so extremely sensitive that on the first contact 
with any substance smeared with turpentine the animal would 
turn quickly away; the effect being essentially the same as if the 
animal had come in contact with heated metal. The fatal defect 
of this experiment is that the sensitiveness of the foot was not 
taken into consideration. I have tried the same experiment as 
far as surrounding the animals with turpentine, but they never 
turned away till they came in contact with the turpentine. If 
they turned away on account of the smell, they would do so before 
touching the turpentine. 

If one observes a snail^ when in motion, it will be seen that the 
superior tentacles are usually held, essentially, in one position, 
occasionally striking an object, apparently not seeing it; but the 
inferior tentacles are constantly in motion, and are bent down 
toward the object on which the animal is moving, but not touch- 
ing it. Taking into consideration the limited power of sight, it 
seems to me that the snail must be assisted by the sense of smell. 

That these tentacles have an important function to serve is evi- 
dent from their anatomic character. A large nerve proceeds from 
the principal of the cerebral or supra-esophageal ganglia, which 
connects at the extremity of the tentacle with a very conspicuous 
ganglionic swelling (pi. 13, fig. 4, 5), which gives off numerous 
nerve fibers to the extremity of the tentacle. That the tentacles 
are not tactile organs is evident from two facts; first, they would 

iTerrestrial moll, and shells of the United States, 
2Zeitschrift fiir Wiss. zoologie. 35:133- 


be unnecessary^ as the foot is well supplied with nerves, and is 
very sensitive; second, though the tentacles are bent down toward 
the object on which the animal is moving, I have never seen them 
touch the object. Furthermore, the tentacular gangliaj are anterior 
to all others, with the single exception of the ganglia of the super- 
ior tentacles, and are attached by their nerves to the cerebral 
ganglia, which, taken in connection with the anterior position of 
the tentacles themselves, corresponds to the position of the olfac- 
tory organs in vertebrates. When the tentacle is withdrawn, the 
olfactory sense still exists; the olfactory organ then closely cor- 
responds to the olfactory organ of fishes. Negatively, the olfac- 
tory organ certainly does exist; but the nerves at the mouth, 
which have been considered by some authors as olfactory nerves, 
are undoubtedly nerves of taste; while the pedal sinus is clearly 
for the secretion of mucus, which the animal so abundantly, 
exudes while in motion. Taking into consideration the anatomic 
details of the inferior tentacles, and innumerable observations of 
the use of these organs by the animal, I have no hesitation in 
afiSrming that they are olfactory organs. 

In some forms of Gasteropoda no tentacles exist, and it will be 
interesting to determine whether in the absence of tentacles the 
olfactory sense is deficient. In relation to this Albany Hancock,^ 

Being engaged at present in the investigation of the anat- 
omy of isome members of this family, my attention was naturally 
directed to this point, and I think that I have obtained satisfac- 
tory proof that these hornless animals have really the sense of 
smell highly developed. The head lobe in the Bullidae is, in fact, 
nothing else than the dorsal (superior) and labial (inferior) ten- 
tacles fused in one continuous mass. This Cuvier asserted long 
ago; and it can be very easily proved on anatomical grounds 
. . . It may therefore suffice to say at this moment, that 
the nerves which supply the oral (inferior) and dorsal (superior) 
tentacles in the Gasteropoda go to this lobe, the former to the 
anterior and the latter to the posterior portion of it; a pretty clear 
proof of its real nature. 

Hearing. The so-called auditory organs consist of two trans- 

1 Ann. and mag. nat. hist. 1852. 


parent vesicles, situated beneath the sheath of the supra-esopha- 
geal ganglia, one on each side, placed immediately on the gang- 
lia and connected with nerves proceeding from the cerebral 
ganglia. They are extremely minute, and are filled with a trans- 
parent fluid, containing a number of small bodies, composed of 
concentric layers of carbonate of lime, frequently hollow at the 
center, called otoliths. During life, and for a short time subse- 
quent, these bodies have a peculiar vibratory motion. 

The size and situation of these bodies, and their nerves, would 
naturally lead to the conclusion that as auditory organs they 
would be of little, if any, use. As with Anodonta, I have 
tried numerous experiments to tesit the sense of hearing. Any 
noise which does not jar the animal, has no effect on it. And 
I have no hesitation in saying that the sense of hearing, if ever 
possessed, has been lost. 

These remarks apply both to Polygyra and to L i m a x. 

Sense of direction. Snails in common with most animals, with 
the exception of man, have what has been called t he sixth sense: . 
that of dire£tion_or^ locality. I had for several months a large 
box, containing about one hundred snails, in one corner of my 
library. At the time I was making sections of shells to illustrate 
this work. I one day examined the snails in the box, and picked 
but three which were to all appearances dead. These I took out 
for the purpose of making sections of the shell. Not having time 
then, I laid them on the window ledge, in the opposite corner o'f 
the room, about 12 feet from the box. Several hours later I 
looked for them, and, not finding them, thought they had been 
accidentally brushed from the ledge. Looking on the floor for 
them, I noticed the peculiar, glass-like trail made by a snail while 
moving. Then, examining carefully the spot where I had laid 
them, I found that, though apparently dead, they were alive, and 
I easily traced the three snails by their trails, which led in an 
absolutely straight direction to the box in which they had been 
kept, and I found them under the edge of the mosquito netting, 
which had been tied over the box, as near to the interior of the 
box as it was possible for them to reach. Afterward I experi- 


mented several times by placing individuals in various parts of 
the room, and once in another room. They almost invariably re- 
turned to the box. 


The animal has a thick vermiform body, vpith a broad, ribbon- 
like pedal disk, having very much the appearance of the so-called 
foot of the P o 1 y g y r a. The mouth, tentacles, etc., are situated 
as in that genus. The anterior part of the body is rounded. The 
posterior is acute and dorsally keeled. 

The mantle is situated on the anterior dorsal part of the body, 
and is somewhat shield-shaped. The anterior margin is rounded; 
the posterior margin angular. It consists of a thick, fleshy mem- 
brane. The anterior part is free from the body, and, when the 
animal contracts, the head is concealed beneath it, the mantle 
coming down before the head like a mask. The posterior part 
is not movable. It contains the rudimentary shell, and covers 
the pulmonary chamber, heart and renal organ. 

The respiratory orifice is situated on the right side of the man- 
tle, about midway of its length; the mantle being notched or 
curved around the orifice. 

The genital orifice is situated anteriorly on the right side as in 

The body is divided into two cavities; the smaller containing 
the pulmonary chamber, the heart, renal organ, and a part of the 
rectum, the larger containing the digestive and reproductive or- 
gans, the nerve ganglia and the principal muscles. 

L i m a X differs from Polygyra in that all the organs are 
contained in the vermiform body, corresponding to the foot of 
Polygyra, and in being possessed of only a flat, rudimentary 
shell. Polygyra resembles a L i m a x " with the greater por- 
tion of the mass squeezed out on the back, and arranged in a 
turbinate manner", and covered by a shell. 

The integument consists of a thick mucous membrane, with a 
muscular substratum, as in the foot of P o 1 y g y r a. It is nearly 
uniformly developed, but is thickest on the mantle, tail and pedal 


disk. On the head and upper part of the body, anterior to the 
tentacles, it is very thin. 

The mantle and body have black markings, which vary in inten- 
sity on different individuals. 

Digestive system 
Plates 15, 16 

The esophagus is very short, and has a diameter of about .6 
mm. It leads into the crop, somewhat abruptly expanding to a 
width of about 4 mmi and continues essentially in a straight line 
for nearly three fourths the length of the body, slightly dimin- 
ishing in diameter. It then contracts, quickly expanding to 
nearly its former diameter, to form the stomach, continuing for 
about one fifth the length of the previous part, gradually dimin- 
ishing in size, then turning abruptly forward and ending in a 
position nearly parallel to the constricted part. 

The intestine leaves the posterior part of the stomach, and 
proceeds anteriorly through the digestive gland, where it turns to 
the left, and, making a broad curve in the gland, again proceeds 
anteriorly, in contact with the previously described portion for 
a part of the distance; then, turning to the right, it forms a loop 
over the retractor muscles, near their origin; again proceeding 
posteriorly on the dorsal surface of the crop, nearly to the con- 
strictor of that organ; again abruptly bending forward and con- 
tinuing in contact with the last described part, passing under the 
pulmonary chamber, terminating at the anal aperture near the 
respiratory orifice. 

The latter two convolutions are oblique to the crop and lie on 
its dorsal part. In nearly all the specimens which I have ex- 
amined they are empty and fiat, even when all the other parts of 
the intestine are filled with the remains of food. They are very 
unlike the rest of the intestine in appearance. Their abrupt 
turning backward and simultaneous decrease in size, and their 
dissimilarity in appearance to the rest of the intestine are very 
misleading, and it requires careful dissection to show the contin- 
uity with the rest of the intestine, as they greatly resemble a 


Salivary glands. The salivary glands are situated on the anterior 
part of the crop, the one dorsally and the other latero-ventrally. 
They vary in shape and size (pi. 23, fig. 5, 6) the dorsally situated 
one being the smaller. They consist of numerous lobuli, which 
are conglomerate. From each gland proceeds a conspicuous duct, 
which enters the buccal body, one on each side of the esophagus. 

Digestive gland. The digestive gland consists of three principal 
lobes, divided into lobules. It, in conjunction with the ovotestis, 
occupies the posterior part of the animal, and also invests the 
greater part of the stomach, and the posterior lateral part of the 
crop. See plate 15, figure 3, for its position, and plate 23, figures 7 
and 8, for its form. 

Generative system 
Plates 15, n 

The general appearance of the generative organs is the same as 
inPolygyra, varying only in details, with the exception of the 

The penis and anterior part of the other organs pass obliquely 
over the anterior part of the crop (pi. 15, fig. 2), a part of the ute- 
rine canal and spermatic duct lying ventrally and to the left of 
the crop. The ovotestis is situated at the posterior end of the 
animal, on the dorsal part of the digestive gland. 

The penis is a long, cylindric body, comparatively much longer 
than in Polygyra albolabris. The posterior end is 
curved and bent on itself. It is destitute of the outer fold or 
so-called prepuce existing in P. albolabris. 

The retractor muscle of the penis is long andi inserted, together 
with the vas deferens, on one side slightly anterior to the ex- 

When exserted, a thin, erect membrane is shown extending 
backward from the meatus; and also membranous folds at the 

The vagina and receptaculum seminis are much smaller than in 
P. albolabris. 

The vas deferens is short, its length being equal to or less than 


that of the penis. For about one half of its length it is thickened, 
annulated and glandular, becoming cylindric and filiform, enter- 
ing the penis on the side, Just anterior to the extremity. 

The uterine canal is conspicuous, but does not present so dis- 
tinctly a sacculated appearance as in P. a 1 b o 1 a b r i s. 

The albumen gland is large, flattened, rounded at each extrem- 
ity, broadest at the anterior, gradually diminishing to the pos- 

The hermaphroditic duct is short, ttexuous, but not conroluted, 
as in P. a 1 b o 1 a b r i s. 

The OTotestis consists of an oval, flattened mass^, formed by an 
aggregation of ceca. It is nearly four times as long as wide; situ- 
ated on the dorsal part of the posterior end of the digestive gland. 
It differs greatly from the ovotestis of Polygyra. 

Circulatory system 
Plates 18, 19 

Heart. The heart is situated at the lower left side of the 
pulmonary chamber. It consists of a single auricle and ventricle, 
each pyriform, placed base to base, the bases being truncated. 
The auricle is anterior to the ventricle and about one half its size. 

Arteries. The aorta (pi. 18, flg. 1) proceeds from the apex of the 
ventricle, and almost immediately divides into two principal 
branches, the anterior and posterior of about equal diameter. 
The aorta divides before leaving the pulmonary chamber, giving 
the appearance of two aortae proceeding from the heart. 

The anterior artery proceeds for a short distance laterally, then 
anteriorly. It supplies the stomach, salivary glands, penis, recep- 
taculum seminis, buccal body and nerve ganglia. At the gangli- 
onic mass it turns abruptly backward, and proceeds along the mid- 
dle of the ventral part of the animal, immediately above the pedal 
sinus; continiiing for about (inc half the length of the animal, then 
bifurcating and entering the foot. 

Where the artery bends forward a hirge branch is given off to 
the crop. This branch almost immediately subdivides, the princi- 
pal branch proceeding anteriorly on the dorsal part of the crop. 


Near the esophagus it bifurcates, a branch proceeding to each of 
the salivary glands, and anterior part of the crop. In its progress 
to the anterior part of the crop it gives off four branches, two on 
each side of the crop. These branches in turn give rise to numer- 
ous others. ' 

The second principal branch (3'), proceeds posteriorly for some 
distance, giving off comparatively few branches. 

At the subdivision of the anterior and posterior crop arteries 
there are two smaller branches (4, 3"), the first of which proceeds 
to the uterine canal, the second directly to the ventral part of the 
crop, giving off several branches principally posteriorly. 

At the ganglionic mass, where the aorta turns downward and 
backward, a branch continues forward under the buccal body {13), 
giving off small branches to the buccal body, muscles, lips, etc. 
Branches from the anterior artery accompany the commissural 
cords connecting the two principal ganglionic masses, forming a 
complete circle, as in P. a 1 b o 1 a b r i s {14), giving off branches to 
the tentacles {15). 

Just previous to its turning backward the anterior artery puts 
out a branch, which subdivides and supplies the penis and vagina 
{11, 12). 

The posterior aorta gives off branches to the stomach, intestine, 
digestive gland, uterine canal, hermaphroditic duct, ovotestis, etc. 
The first branch follows the course of the intestine, entering a lobe 
of the digestive gland, and ramifying through it. Very near this 
the artery gives off a branch, which proceeds along the hermaph- 
roditic duct to the ovotestis. Two small branches have previously 
been given off to the hermaphroditic duct. Several small branches 
are now given off to the intestines at frequent intervals. 

From the opposite side of the artery a branch proceeds to the 
upper attenuated end of the principal lobe of the digestive gland, 
giving off numerous branches throughout the lobe. 

The next branch continues along the outer surface of the large 
lobe of the digestive gland, giving off numerous branchlets, which 
ramify throughout the lobe. 

Immediately after the anterior artery bends abruptly toward the 


anterior portion of the animal, the large artery, which supplies 
the stomach, gives origin to a comparatively large branch to the 
digestive gland, and gives off numerous branches, both to the 
intestines and digestive gland. The next branch proceeds from 
the same side of the artery, continuing to the digestive gland, 
giving off numerous branches and finally forming a network in 
the lobes of the digestive gland (pi. 18-, fig. 9). 

The next branch is from the opposite side of the artery, and con- 
tinues on the posterior part of the stomach. This branch is prom- 
inent. At about one half the distance from the artery to the ven- 
tral part of the stomach it bifurcates, one branch again bifurcat- 
ing; one branch containing latero-anteriorly and the other dorso- 
auteriorly. The main branch continues to the veniral part of the 
stomach, bifurcating; the branches continuing mainly on the ven- 
tral part of the stomach. 

The next prominent branch is from the opposite side of the ar- 
tery. The principal artery of this branch continues to a lobe of 
the digestive gland, and ramifies through it; a smaller branch con- 
tinues to the intestine. 

The next conspicuous artery is from the large artery which sup- 
plies the uterine canal and the so-called prostate gland. 

Pulmonary cavity. The pulmonary cavity lies below the mantle 
and is of essentially the same shape. It is situated, immediately 
below the shell cavity, and contains the heart, renal organ, the 
posterior part of the rectum and the anus. It is separated from 
the visceral cavity by the muscular peritoneum or diaphragm. 

The respiratory orifice is situated on the right side of the body, 
at the edge of the mantle (pi. 23, fig. 1, 1). This orifice opens and 
closes at regular intervals; the normal respiration seems to be 
from 16 to 18 times a minute, though it is frequently variable. 
When open the orifice is circular, and is closed by muscular fibers 
which surround it. 

The pulmonary veins, or rete, are situated mostly on the roof of 
the cavity. They are numerous, anastomosing, and occupy nearly 
the whole surface (pi. 19, fig. 2). 

Veins. The veins are situated mostly in the substance of the 


body, not being on the surface as is frequently the case with the 
arteries. As in P. a 1 b o 1 a b r i s, they are not simply lacunae or 
spaces in the body, but have a distinct wall. 

The branches of the arteries grow smaller and smaller, and 
finally consist of an anastomosing network, which communicates 
with a similar network of veins; these capillaries gradually coal- 
escing, forming larger branches, which combine to form large 
veins, connecting with the sinus of the pulmonary cavity. There 
are two veins parallel with, and in close contiguity to the pedal 
gland or sinus. 

The two largest veins are situated in the integument of the sides 
of the body, one on each side. They are connected with the ar- 
teries by innumerable ramifications. They are illustrated on plate 

18, figures 2 and 3; but only the large vessels are shown, the smaller 
ones not being represented. There are also smaller veins in the 
lateral anterior parts of the integument, and a large vein in the 
dorsal part of the integument. 

The blood proceeds from the heart through the arteries, entering 
the veins from the arteries, and carried by them to the renal organ 
and the pulmonary cavity, where it is aerated, and returned by the 
large pulmonary veins to the auricle, thence to the ventricle. 

Kidney. The kidney is situated in contiguity to the heart (pi. 

19, fig. 3), and Ls a large subovate, glandular organ. From the 
lower right side proceeds a duct, which continues along the lower 
part of the pulmonary cavity to the rectum, continuing along- 
side of this; curving near the extremity, the parts of the curve 
being in apposition to the rectum, and opening in close contiguity 
to the anus. 

Nervous system 
Plate 22 

The two principal ganglionic masses are the supra and infra- 
esophageal [1, 2). 

The supra-esophageal ganglia are situated above the esopha- 
gus, and just posterior to the buccal body, when the animal is 
extended. Of course when the animal is contracted the relative 
positions are altered. The ganglionic mass consists of three pairs 


of ganglia; the three pairs being united by an extremely short 
broad commissural cord, which is very inconspicuous; the inner 
pair of ganglia having somewhat the appearance of coalescing. 

The outer pair are larger than the others and somewhat ob- 
scurely kidney-shaped. The anterior margin being rounded and 
continuous; the posterior part being bilobed, the inner lobe larger 
than the outer. 

The second, or median, pair of ganglia are in contact with the 
inner part of the first mentioned pair for their entire length. 
They are curved, broadest at the base, and tapering to a point, 
very narrow at their widest point. 

The third, or inner, pair are nearly in contact at their anterior 
part, gradually diverging posteriorly. They are comparatively 
narrow, though twice the width of the second pair, and are about 
four times as long as wide. They are each obscurely divided into 
four lobes, of which the anterior is subtriangular, the posterior 
nearly round, and the remaining two subquadrangular. 

The infra-esophageal ganglionic mass is much larger than the 
supra-esophageal, (2), and consists of six pair of ganglia, aggre- 
gated more or less in one mass. 

With the exception of the first pair the ganglia are regularly 
bilaterally arranged; one of each pair being on opposite sides of 
a median line. 

The first pair consist of a large and a small ganglion, the 
larger one being ovate with a length about equal to twice its 
greatest diameter. Immediately anterior to this is a small 
ganglion, about one third the size of the first mentioned ganglion. 

The next pair are situated one on each side, and partially un- 
derneath the first pair. They are subovate in form and are about 
one and one half times the size of the first mentioned pair. 

The next pair are each about the size of the first mentioned 
ganglion, and are oval or subovate in form, and are situated 
mostly underneath the second pair, their anterior ends projecting. 
The posterior ends of the second pair project, laterally, beyond 
the third pair. 

The fourth pair are subovate in form and situated beneath the 
second and third pair. 


The fifth pair are situated below the fourth pair. Their inner 
margins are nearly in contact. 

The large cephalic artery passes through the ganglionic mass, 
bounded above and below by the third and fifth pair of ganglia, 
and laterally by the fourth pair. 

The sixth pair are below the fourth and fifth pair of ganglia, 
and when the ganglionic mass is viewed from above are almost 
hidden from sight. 

The ganglionic masses are connected by two pairs of commis- 
sural cords, the upper ones of which proceed from the second pair 
of the supra-esophageal ganglia, and continue to the under part 
of the fourth pair of infra-esophageal ganglia. The inferior pair 
of cords proceed from the posterolateral part of the lower lobe of 
the inner, or third pair of supra-esophageal ganglia, and continue 
to the lower part of the sixth pair of infra-esophageal ganglia. 

T'wo smaller ganglia are situated near the dorsal surface of the 
posterior part of the buccal body, one on each side of the esoph- 
agus, just as it leaves the buccal body. They are comparatively 
small, a little less than three times as long as wide, and are 
divided into three nearly equal lobes, (3) the anterior one being 
broader and shorter than the other two, which are nearly round. 

The two ganglia are connected by a strong commissural cord 
proceeding from the posterior lobes. 

The buccal ganglia are connected with the cerebral ganglia by 
two commissural cords, which proceed from the under surface of 
the inner pair of cerebral ganglia, to the outer and under part 
of the anterior lobes of the buccal ganglia. 

There are ganglionic swellings in the extremities of both the 
superior and inferior tentacles. That in each superior tentacle is 
digitate in form, the palm being exaggerated in size and the 
fingers short. From each of these processes, or fingers, numerous 
fibers proceed to the thin integument at the end of the tentacle. 
The ganglia of the inferior tentacles are pyriform^ the largest end 
being nearest to the extremity of the tentacle, and giving off 
numerous fibers to the extremity of the tentacle. 

A small ganglion is situated near the first branching of the 


aorta on the dorsal part of the stomach. It is subovate in form, 
gradually enlarging from its posterior to its anterior extremity, 
and is about four times as long as wide (4)- 

From the outer anterior part of the principal ganglia proceeds 
a stout nerve to the extremity of the superior tentacle (5). 
Within the tentacle this nerve gives origin to a slender nerve 
proceeding to the eye, the optic nerve. From a point closely 
contiguous to the first mentioned nerve, but nearer to the anterior 
miargin, proceeds a nerve, smaller than the first, which near the 
anterior extremity of the animal bifurcates, one branch going to 
the mouth (7), the other to the ganglia at the extremity of the 
inferior tentacle (6). From a point slightly nearer to the anter- 
ior margin proceeds a nerve, which near the mouth bifurcates 
and gives off nerves to the mouth and adjacent parts of the in- 
tegument (7'). From the anterior lobe of the inner ganglia nerves 
proceed to the muscles and integument of the superior pair of 
tentacles (S). From the inner part of the principal ganglia pro- 
ceed commissural cords, which unite with the anterior lobe of the 
buccal ganglia {3'). 

The posterior lobes of the buccal ganglia are united by a short, 
broad commissural cord (3"). 

From the anterior lobe of each buccal ganglion arise two 
nerves, which proceed to the anterior part of the buccal body, 
giving off numerous branches (9). 

From the inner part of each median lobe arises a nerve which 
continues posteriorly alongside the esophagus {10); and from the 
posterior lobe two nerves, which supply the posterior part of the 
buccal body (11). 

The cephalic artery passes through the infra-esophageal gang- 
lionic mass, the ganglia forming a ring, and in an uninjected 
specimen might easily be mistaken for a large nerve. 

From the posterior part of the dorsal ganglia proceed five 
nerves, three of which are of nearly equal diameter; the other two 
are smaller. The one to the left is free for a short distance, then 
buries itself in the substance of the retractor muscles, continuing 
to the origin of the muscles in the muscular layer. 


The median nerve is directed posteriorly to the right {21, 21'), 
and furnishes nerves to the pulmonary cavity, respiratory orifice 
and anus. 

The nerve from the right of the ganglion continues posteriorly 
to the large artery, entering the foot, to a minute oblong gang- 
lion (4). The ganglion gives off five nerves, of which the larger 
arises in the outer anterior part, and proceeds along the intestine 
in close contiguity to the artery. 

Immediately anterior to this is a small nerve proceeding to the 
pulmonary cavity. 

Prom the opposite anterior part proceeds a nerve supplying 
the hermaphroditic generative organs. 

From the posterior part proceed two nerves supplying the 
stomach and digestive gland. 

In the inferior part of each of the second pair of infra-esopha- 
geal ganglia arises a large nerve which passes posteriorly and 
outward, entering the integument just anterior to the pulmonary 
chamber; the branches of these nerves supplying that organ and 
the heart. 

From the posterior part of these ganglia proceed two very 
large nerves, which continue to the postero-basal part of the 
animal, parallel to and at a short distance from the pedal gland, 
giving off several branches to the base of the foot {12, 13% 13"). 

In the inferior part of the other ganglia arise five other pairs 
of nerves {15-19), which are inserted in the integument at the 
sides; and other more numerous nerves, which are inserted in the 

Muscular system 

Plates 19, 20 

The principal muscles, viz, the retractor muscles of the anterior 
part of the body, the buccal body and the tentacles, have their 
origin in the inner muscular layer, just posterior to the pulmon- 
ary cavity on the right side. 

They at first consist of two broad, flat, somewhat connected 
bands (pi. 19, fig. 1, 2). At about one half the distance to the 
nerve ganglia these bands are subdivided, giving origin to the 


ocular tentacular muscles (3), and the retractor muscles of the 
buccal body (5). The superior, or ocular tentacular muscles, 
shortly subdivide, giving origin to the muscles of the inferior, or 
olfactory tentacles (4), which are much smaller than those of the 
ocular tentacles. 

The muscular sheath of the supra-esophageal ganglia is con- 
nected with the superior tentacular muscles by two flat muscular 
bands on each side (pi. 20, fig. 1, 2). 

In the anterobasal part of the animal arises a set of three 
muscles on each side (pi. 19, 20, fig. 1), the posterior one (1) arising 
under the muscles of the superior tentacle, and inserted near the 
lips of the animal. The middle one (8) is inserted in the muscles 
of the inferior tentacle. The anterior and largest muscle (5) 
passes over the superior tentacle muscles and is inserted at the 

Posterior to these a muscle on each side has its origin in the 
basal part of the animal, and is inserted in the muscle of the in- 
ferior tentacle (10). 

In figure 2, plate 20, the retractor muscles have been cut close 
to the buccal body, and that organism has been turned forward 
to show its under side, and also the base of the anterior part of 
the body cavity. 

On each side of a basal median line, and at a short distance 
from it, a thin, flat band of muscular fibres arises, which is in- 
serted at the extreme anterior end of the body at the mouth, im- 
mediately below the anterior end of the buccal body {1). These 
two bands of muscles, at their anterior part cross each other at 
an angle of about 45°. Their function is to contract the basal 
part of the anterior portion of the body. 

On each side of the buccal body the lower part of the lateral 
lips can be observed, showing as a white mass, somewhat regu- 
larly longitudinally divided. From the posterior part of each 
mass proceed two muscles, one broad, the other narrow, uniting 
with the muscles of the inferior tentacle (pi. 19. fig. 2, 3). 

On the right side of the figure the lip and its muscles are shown 
in their natural position; on the left side of the figure the lip and 


its muscles, as well as the muscle of tlie inferior tentacle, are 
turned forward in order to show a short, broad muscle, which has 
its origin in the anterior basal part of the body, and is inserted 
principally in the muscles of theinferior tentacle, but some of the 
fibers are inserted in the large muscles of the lip (pi. 20, fig. 2, If). 

On the under side of the buccal body, toward the posterior part, 
are several moderately broad, horizontal bands of muscles, which 
are partially concealed by overlying longitudinal muscles {10). 
Bands of muscles are situated on the ventral surface of the 
buccal body, proceeding from the posteroventral part and diverg- 
ing to the sides (6). Strong bands of muscles originate in the 
middle ventral part of the buccal body, and, slightly diverging, 
are inserted in the anterobasal part of the animal, just under the 
anterior part of the buccal body (5). A band of muscles is 
situated on each side of the buccal body, proceeding from the 
posteroventral to the anterolateral part of the buccal body (7). 

Numerous fibers have their origin in the anterior part of the 
buccal body, and are inserted in the integument of the mouth. 
The entire outer walls of the buccal body are composed of mus- 
cular fibers, both transverse and longitudinal. 

Looking down on the buccal body, the following muscles can 
be observed: a pair of delicate muscles, one on each side, arising 
in the inferior posterolateral part of the buccal body, and in- 
serted in the cephalic integument; another delicate pair arising 
in the anterolateral part of the buccal body, and inserted in the 
integument, near the 'base of the inferior tentacles; a pair which 
proceed laterally from'the anterior basal part of the buccal body, 
being inserted in th« integument each side of that body. 

The integument or skin of the animal is composed of two layers, 
the inner of which is composed of interlaced muscular fiber; and 
the viscera are inclosed by a very thin muscular peritoneum. 
The first layer is composed of unstriped muscular fibers, ar- 
ranged transversely, longitudinally and obliquely. 

The peritoneum is composed of muscles arranged transversely 
and longitudinally, and gives rise to the retractor muscles pre- 
viously described. 



When the ova have reached a certain stage of maturity they 
leave the ovary. This process is known as ovulation. They pass 
through the hermaphroditic duct (pi. 16, fig. 1, 10), to the albumen 
gland (9), and thence to the oviduct (7) ; from which they are dis- 
charged, that is, laid. 

The composition of the egg is as follows : in the interior of the 
egg is the germinative vesicle, or egg nucleus, which contains a 
still smaller vesicle, or germinative dot; surrounding these is the 
yolk, which is a liquid of varying consistency. In the snail it is 
transparent. These parts of the egg are formed in the ovary. 
The albumen surrounds the yolk, and in the case of L i m a x is 
semitransparent, less so than the yolk. This substance is not 
formed in the ovary, but is secreted by the albumen gland (pi. 16, 
fig. 1, 9). The albumen is surrounded by a membrane, which in 
L i m a X is eemi-transparent, so that, when the egg is viewed 
under the microscope by transmitted light, the movements of the 
embryo can be observed, though not distinctly enough for study. 

In the eggs of the P o 1 y g y r a the outer covering is still 
membranous, though much thicker than in Li max, and it is 
opaque. After the escape of the young P o 1 y g y r a, it has very 
much the appearance of a calcareous shell. 

Soon after fertilization the egg undergoes the process of seg- 
mentation, that is breaks up into cells. It first divides into four 
equal cells; and then smaller cells are formed from the division of 
the first four, so as to lie outside of them. The smaller cells now 
subdivide and spread over the first four. The cell mass is dilated, 
becoming hollow. The large cells subdivide and sink into the 
hollow of the sphere, forming an elongated groove, the origin of 
which at the surface is known as the blastopore. This orifice 
subsequently closes up. The invaginated cells, formed by the 
subdivision of the large cells, are known as the endoderm. The 
outer layer, formed by the division of the smaller cells, is known 
as the ectoderm. This condition of the egg forms the gastrula 
stage (pi. 24, fig. 10-14). 

A dilatation of the ectodermal walls now takes place, a con- 


siderable space being left between the ectoderm and endoderm 
(pi. 25, fig. 6 and succeeding figures). 

The body of the animal as first observed consists of a slight 
swelling of the upper side of the cell mass (pi. 25, fig. 7). 

In the following descriptions it must be remembered that the 
ventral surface of the animal is uppermost. 

The swelling above mentioned very soon shows a tendency to 
divide into two parts (pi. 25, fig. 9, and pi. 24, fig. 17), the anterior 
part of which is the foot proper, the posterior part the mantle, 
shell sac, etc. 

Even at this early stage the embryonic shell can be observed, 
consisting of a few dark colored crystalline plates, not yet united. 

At this stage the mouth appears at the position formerly occu- 
pied by the blastophore; which has disappeared or been closed, 
and consists of an invagination of cells, bounded by lateral lips 
(pi. 24, fig. 20). 

The shell sac and mantle enlarge much the faster proportion- 
ally, as shown in plate 25, figures 11, 12. 

In figure 12, and more distinctly in figure 13, the development 
of the tentacles is shown, which at this stage have the appear- 
ance of flat circular disks. 

The body is very small; from its extremity a circular semi- 
transparent appendage^ the podocyst, is developed, consisting of 
two walls, which are connected by reticulated muscular cells. 
The body now rapidly develops, as shown in figures 15 and 16, 
plate 25.' 

The shell has also increased in size, consisting of numerous crys- 
talline plates, not yet united. 

The ectodermal sac and podocyst have also increased in size. 
The surface markings are now apparent, and the beating of the 
heart is plainly visible beneath the mantle. 

The smaller tentacles, the lateral lips of the mouth, the odon- 
tophore and the beginning of the alimentary canal have appeared; 
the pedal sinus is also apparent. 

At this stage (pi. 25, fig. 17-21), the ectodermal sac and podo- 
cyst have reached their greatest development, and hereafter 
gradually diminish in size till completely absorbed. 


The podocyst is now an object of great beauty, to which no 
drawing can do justice. It undergoes a rhythmic movement of 
dilatation and contraction, sometimes being so expanded as to 
include the rest of the embryo, then contracting 'to less than one 
half that size. The ectodermal sac also undergoes a similar con- 
traction and expansion, sometimes in harmony with, and again 
alternating with that of the podocyst. 

The whole embryo, from the stage represented by figure 11, has 
a rotatory motion. 

In the stage represented by figure 19, I have first observed the 
•'primitive kidneys." They are situated on each side of the en- 
doderm, and consist of a series of curved elongate cells, within 
which concretions are developed, and terminate in a duct (pi. 28, 
fig. 4). 

The cells proper are apparently angular or of different shapes 
(pi. 28, fig. 1, 2); but this is due to mutual pressure, as when the 
sac is ruptured the cells flow out perfectly spherical^ as shown in 
figure 3. 

As development proceeds a movement of the cells takes place 
from the ectodermal sac into the constantly enlarging body (pi. 26, 
fig. 1). The alimentary canal accompanies the cells; the anus 
alone remains in its original position. 

In the stage represented by figure 5, plate 26, the ectoderm so 
closely bounds the endoderm as not to be apparent. The ectoder- 
mal cells have been largely absorbed into the body, or, rather, 
changed into body tissue, and the podocyst is very much reduced 
in size. The tentacles are assuming their mature form, and the 
mouth and lips are very distinct. The intestine is nearly com- 
plete and the larger endodermal cells have, in great part, been 
converted into the substance of the digestive gland. The respira- 
tory orifice, the mantle and shell are well formed. 

Heretofore the embryo has been represented with the ventral 
part uppermost, but in figure 2, plate 27, it is represented, in a 
reverse position, as in adult condition. 

In this stage the endodermal cell mass has been almost entirely 
changed into the alimentary canal and its appendages, the podo- 


cyst has been almost entirely absorbed, and the various organs 
are approaching their perfect condition. Figure 1, plate 2~, 
represents the appearance of the embryo in the egg capsule at this 
stage (8). The absorption of the podocyst continues for a short 
time longer, when the animal becomes completely formed and 
emerges from the egg. 

A careful study of the figures on plates 24-28, and their explana- 
tions, will perhaps show more clearly the development of the 
embryo than the preceding text. 

It occasionally happens that there are two ova in one egg cap- 
sule, and in one instance I have observed four embryos in one 
egg capsule (pi. 27, fig. A, 5). 

Time of laying eggs 

In the latter part of September I had a number of specimens 
sent to me. Within a very few days a majority of them laid 
eggs. Of course the very short time of confinement, only two or 
three days^ made no difference in the time of laying. Others did 
jiotjaytheir eggs till the middle of November, when naturally 
they would have been hibernating for a mdntET It would seem 
therefore that some of the animals lay their eggs in the fall, and 
others not till the following spring. 

The eggs are laid on the surface of the ground, under dead 
leaves, logs, stones, or any sheltered space, where the requisite 
moisture can be obtained. They are laid in a cluster. The num- 
ber in the clusters observed by myself varied from 50 to 130. They 
are soft and before leaving the animal must be very much com- 
pressed; for a mass of eggs occupies a larger space than the ani- 
mal itself. When first laid they are of beautiful appearance, 
semi-transparent, resembling globes of liquid. Light transmitted 
through them becomes a beautiful golden color. They are 
usually round, but sometimes oval, and when they are in apposi- 
tion a part is frequently pressed in till it is concave, but, as the 
embryo grows, this part is pushed out, the egg becoming regularly 
round or oval. 

It would seem probable that all eggs laid at the same time 


would hatch out at about the same time, but I had several clusters 
of eggs laid within 24 hours of each other, kept in the same box, 
and necessarily under the same conditions, and when some of 
these were hatched out, the embryos of other clusters were not 
more than half developed. This statement has been questioned, 
but I am absolutely sure of the correctness of my observations in 
this respect. 

Several of the clusters had not been fertilized, as shown by the 
non-development of the embryo. 

Binney declares that eggs that had been several times subjected 
to a great heat in an oven, so as to become perfectly dry and 
shriveled, when placed in a moist place regained their lost form, 
and young were produced from them. While not doubting this 
statement, my experience has been that, when the egg became 
dry and shriveled, the embryo was killed; though when supplied 
with moisture the vitality under adverse circumstances was 

Embryos that I have dissected from the egg and placed in water 
retained life from 24 to 48 hours. Even when the power of 
motion was lost, the heart continued to beat. 

Rate of growth 

Even under the same conditions the rate of growth of all the 
animals is not uniform. I have at this writing more than 100 
animals that were hatched at about the same time. They have 
been kept in the same box and of course under Jhe same^condi- 
tions. But they vary decidedly in .sizej somejbeing not more than 
half the size of others. 

At least two seasons are required for an animal to reach 
maturity. I have now specimens that were hatched nearly 10 
months ago, which have been kept in a warm room during cold 
weather, therefore not hibernating, and supplied with an abund- 
ance of food; yet some of them are not half grown. They prob- 
ably developed as rapidly as in natural conditions. Naturally 
they would hibernate during cold weather, and the growth would 
not be as great in 10 months as in confinement. 


Polygyra albolabris 

1-3 Dorsal, profile and ventral views of an adult shell, natural 

4 A profile view, showing a more flattened form than in 
fig. 2. 
5, 6 Ventral and profile views of a young shell, the peristome 
being as yet unformed. 

7 Ventral view of an adult shell, showing the form of the 

under side of the peristome. 

8 Profile view of a shell just after leaving the egg, x 10, the 

perpendicular line to the left of the figure showing the 
natural size. Figures 9, 10 and 11 are also enlarged, the 
perpendicular lines to the left of the figure showing the 
natural size as in fig. 8. 

9-11 Showing succeeding stages of the form of the shell before 
reaching maturity. 

12 An adult shell. 

13 In this figure a part of the lower volution of the shell is 

broken away to show the interior. 

14 A section of a shell. The outer part of the shell is ground 

away in order to show the columella. 

15 A section. The columella has been ground down to show 

its interior. 


1 An egg natural size and enlarged. 

2 A view showing the shell within the egg. 

3 A view showing the shell emerging from the egg. 

4 Dorsal and profile views of a shell, newly hatched, natural 

size and enlarged. 



5, 6 Profile and ventral views of a shell about one month old, 

natural size and enlarged. 
7 Dorsal and lateral views of a shell about three months 

old, natural size. 
8, 9 The same, x 3. 

10 Surface of the shell, x 10. 

11 The same, x 20. 

12 Transverse section of the prismatic layer of the shell, x 100. 

13 A section of a part of the peristome, x 40. 

14 A section of the peristome and a part of the shell, x 10. 

15 A section of the shell; cuticle; outer layer; median layer; 

inner layer. 

16 A section of the volutions, x 2. 

17 One volution more highly magnified, x 6. 

18 A transverse section of the peristome, x 2. 


1 Dorsal view of a shell and extended animal. The smaller 

figure represents a newly hatched animal. Both figures 
are natural size. 

2 Profile view of shell and extended animal, natural size. 

3 An animal from which the shell has been removed, show- 

ing protruding penis; 1 penis; 2 anus: 3 stomach; 4 ovo- 
■testis; 5 intestine; 6 digestive gland; 7 kidney; S pulmon- 
ary vein. 

4 The same view as in figure 3, the volutions being partially 

uncoiled to show the position of the generative organs. 
For explanation of the organs see plate 23, figure 9. 

5 Ventral view, the animal being retracted within the shell ; 

1, respiratory orifice. 

6 Laterobasal surface of the integument, x 6. 

7 A part of the integument of the dorsal part of the foot, x 6. 



1 The buccal body, enlarged, from above; 1 the buccal body; 

2 esophagus; 3 salivary ducts; Jf nerves uniting cerebral 
and buccal ganglia; 5 retractor muscles; 6 depressor mus- 
cles; 7 levator muscles; S protractor muscles; 9 labial 

2 The buccal body. The dorsal wall is cut through, and 

separated, displaying a part of the interior; 1 buccal 
body; 2 muscular wall of the buccal body; S lateral lips; 
4 radula^ or lingual ribbon; 5 sac of radula; 6 esophagus; 
7 salivary duct. 

3 The buccal body laid open, from above; 1 lateral lips; 2 

muscular wall of the buccal body; S odontophoral carti- 
lage; Jf radula; 5 sac of radula; 6 retractor muscles. 

4 Longitudinal section of the buccal body; 1 odontophoral 

cartilage; 2 radula; 3 sac of radula; 4 muscular wall; 5 
jaw or dental plate; 6 esophagus; 7, 8 muscles connected 
with the radula; 9 opening of the pedal sinus; 10 pedal 
sinus; 11 muscular sole of animal; 12 infra-esophageal 
ganglia; 13 supra-esophageal ganglia; i4 retractor mus- 
cles; 15 tentacular muscle. 

5 A eection of the animal showing: 1 pedal sinus; 2 large 

veins; 3 small veins; ^ mucus glands; 5 muscular sole 
of foot. 

6 Perpendicular section of the buccal body; 1 esophagus; 2 

salivary ducts; 3 lingual ribbon or radula; 4 sac of 
radula; 5 odontophoral cartilage. 

7 Vertical section, the same as figure 6, the esophagus, etc., 

have been removed, bringing into view the radula; 1 
radula; 2 odontophoral cartilage. 



1 A view from the under side of the head, showing the mouth 

and lips, x 5. 

2 The jaw, x 10. 

3 The digestive organs; 1 the buccal body; 2 esophagus; 2' 

the crop; 3 salivary ducts; 4 salivary glands; 5 stomach; 
6 intestine; 7 rectum; 8 anus; 9 digestive gland; 10 ducts 
of digestive gland; 11 ventricle; 12 auricle; 13 pericar- 
dium; 14 kidney or renal organ all x 2. 

4 Crop and salivary gland, x 6. 

5 Heart and kidney as seen from the exterior. 



The lettering on each of the figures refers to the same organ. 
1-6 Transverse sections of the body from the buccal body to 
near the posterior extremity of the foot. 

1 genital opening; 2 penis; 2' sac of radula; 3 esophagus; 4 
salivary duct; 5 tentacular muscles; 6 vas deferens; 7 
peritoneum; 8 pedal sinus; 9 oviduct; 10 vagina; 11 uter- 
ine canal and spermatic duct; 12 the mantle. 

7 The stomach and a part of the intestine as seen from above. 

8 The stomach as seen from below, showing also the ducts of 

the digestive gland and their connection with the stom- 


Generative organs 

1 1 genital aperture; 2 penis; 3 outer fold or prepuce; 4 
vagina; 5 receptaculum seminis; 6 vas deferens; 7 free 
oviduct; 8 uterine canal; 9 spermatic duct; 10 talon, or 
accessory gland of the hermaphroditic duct; 11 hermaph- 
roditic duct; 12 ovotestes; 13 retractor muscle of the 
penis; I4 albumen gland, all x 3. 



2 An enlargement of a part of the generative organs : 1 her- 

maphroditic duct; 2 talon; 3 albumen gland. 

3 Accessory gland, or talon, seen from above, x 6. 

4 The same as seen from below, x 6. 

5 The OTotestes, x 5. 

6 The cecal tubes of the ovotestes, x 30. 

7 A transverse section of the ceca of the ovotestes, showing 

the spermatic within the ovarian tube, x 30. 


1 An exterior view of the penis, x 3. 

2 A longitudinal section of the penis, showing the corrugated 

fold, or pilaster, of the interior, and the maimer of the 
formation of the outer fold, or prepuce, x 3. 

3 The penis opened from the dorsal part, showing the corru- 

gations of the lining membrane, and the corrugated fold, 
pilaster, of the membrane, x 3. 

4 A part of the corrugated and papillate lining membrane, 


5 A transverse section of the vas deferens, x 6. 

6 A tranverse section of the vas deferens, showing its en- 

trance into the penis, x 6. 

7-9 Sections of the penis, figure 9 being beyond the pilaster, 

10 An exterior view of the vagina and receptaculum seminis, 


11 A longitudinal section, showing the muscular folds of the 

vagina, x 4. 

12 A transverse section of the vagina, and of the oviduct at its 

entrance into the vagina, x 6. 

13 A transverse section of the vagina at the point indicated by 

the dots in figure 11, x 6. 

14 A transverse section of the receptaculum seminis, x 6. 



Circulatory system, 1 auricle; 2 ventricle; 3 posterior aorta; 

4 anterior aorta; 3' artery to albumen gland; 3" artery 
to digestive gland; 6 artery to stomach; 7 artery to her- 
maphroditic duct; 8 artery to uterine canal and sper- 
matic duct; 9 artery supplying muscular collar, pedal 
muscles and crop; 10 artery to pedal muscles; 11 artery 

• to muscular collar; 12 artery supplying crop; 13 arteries 
to salivary ducts; U artery to base of foot; 15 artery 
supplying nerve commissures; 16 arteries to the tenta- 
cles; 16' artery to buccal body; 11 artery to vagina; 18 
artery to the penis; 19 artery to the intestine; 20 artery 
to the ovotestes. 



1 1 Pericardial cavity; 2 auricle; 3 ventricle, x 6. 

2 Shovring the stomach and under or inner face of the digest- 

ive gland, and the arteries supplying that part of the ani- 
mal: i auricle; 2 ventricle; 3 stomach; 4 intestine; 5 ducts 
of digestive gland; 6 artery to the smaller or superior 
lobe of the digestive gland; 7 arteries to the ovotestes; 
8 kidney; 9 rectum; 10 digestive gland, x 3. 

3 The outer part of the digestive gland and its arteries. 

The numbering lias the same signification as In figure 2. 

4 The stomach and its arteries, x 3. 

5 The crop and salivary gland and their arteriess, x 3. 

6 ShovFing the arteries of the ceca of the ovotesitis. 



1 An enlargement showing the heart and the veins of the 
pulmonary cavity: 1 auricle; 2 ventricle; 3 the large pul- 
monary vein leading to the auricle; // the afferent veins; 

5 the efferent veins; 6 the large vein or venous sinus iu- 
circling the pulmonary cavity. 



2-4 Figures showing the position of the pulmonary cavity, in 
relation to the volutions of the animal. 

Nervous system 

a supra-esophageal or cerebral ganglia; B infra-esophageal 
ganglia; c commissures connecting the supra and infra-esophageal 
ga/nglia; d nerves to the ocular or superior tentacles; e ganglionic 
enlargement at the extremity of the ocular tentacles ; f optic nerve ; 
g eye; h nerves to olfactory, or inferior, tentacles; i ganglionic 
enlargement at the extremity of the inferior tentacle; k nerve to 
mouth; I, m nerves supplying the mouth and adjacent parts; n buc- 
cal ganglia ; o commissural cords connecting the supra-esophageal 
and buccal ganglia; p nerves supplying the generative system and 
the visceral mass; r nerves to the muscular collar and pulmonary 
cavity; s nerves supplying the basal parts of the animal; t nerves 
supplying the laterobasal parts of the foot; u nerves to the integ- 
ument on each side. 


The same lettering refers to the same muscles in each figure. 
1-2 The retractor muscles of the buccal body, foot and tentacles 

enlarged. 1 retractor muscles of the buccal body; 2 re- 
tractor muscles of the foot; 3 retractor muscles of the 
ocular tentacles; 4 muscles continuing to the lips and ten- 
tacles; 5 muscles of olfactory tentacles; 6 muscles of 
mouth; 7, 8, 9 muscles of the buccal body; 7 levator 
muscle; 8 protractor muscle; 9 depressor muscles. Figure 
1 shows the muscles as seen from above; figure 2 is a 
lateral view. 

3 An enlarged section of the tentacles: 1 integument; 2, 2' 
tentacular muscles; S, 3' tentacular nerves; 4, V ten- 
tacular ganglia; 5 optic nerve; 6 eye; 7 muscles to the 
mouth; 8 nerves to mouth. 



4 An enlargement of the ganglion of the ocular tentacles, 

optic nerve and eye, x 12. 

5 An enlargement of the nerve and ganglion of the olfactory 

tentacle, x 12. 

6 Cryptoicus minutissimus, highly magnified. 

Polygyra albolabris dissected and the organs separ- 
ated: 1 buccal body; 2 esophagus; 3 crop; 4 stomach; 5 intestine; 
6 rectum; 8 anus; 9 superior lobe of digestive gland; 10 inferior 
lobe of digestive gland; 11 ducts of digestive gland; 12 salivary 
ducts; 13 salivary glands; IJt penis; 15 vagina; 16 receptaculum 
seminis; 11 retractor muscle; 18 glandular portion of the vas 
deferens; 19 vas deferens; 20 spermatic duct; 21 uterine canal; 
22 spermatic duct; 23 albumen gland; 2Jf hermaphroditic duct; 
25 accessory gland of duct, or talon ; 26 ovotestes ; 21 renal organ 
or kidney, the primary ureter along its upper side; 28 secondary 
ureter; 29 opening of ureter, or renal duct; 30 ventricle; 31 
auricle; 32 pericardiac cavity; 33 pulmonary vein; 3^ large blood 
vessel connecting with pulmonary rete; 35 pulmonary rete; 36 
supra-esophageal ganglia; 31 tentacular nerve; 38 nerves to 
mouth and inferior tentacle; 39 superior tentacles; 40 integu- 
ment; Jfl muscles from buccal body of integument; ^2 superior 
tentacular muscle; J^3 inferior tentacular muscle; 44 retractor 
muscles; 45 muscular peritoneum; 46 muscular collar; 47 cephalic 
artery; If8 nerve to muscular collar. 


Limax maximus 

The same letters apply to the same organ in each figure. 

1 The dorsal part of the integument is cut and turned back, 

showing the various organs in position. 

2 The pulmonary chamber, heart, etc. are turned back, show- 

ing the under side of the organs, and the parts concealed 
by them in figure 1. 



3 The organs are separated, and each organ is shown more 
distinctly. 1 buccal body; 2 salivary ducts; 3 salivary 
glands; 4 crop; 5 intestines; 6 rectum; 7 stomach; 8 
digestive gland; 9 penis; 10 retractor muscle of the 
penis; 11 receptaculum seminis; 12 uterine canal; 12' 
spermatic duct; 12" albumen gland; IS hermaphroditic 
duct; IJf ovotestes; 15 nerves to the basal part of the 
body; 16 large veins in the integument of the sides of 
the animal; 11 ventricle; IT auricle; 18 kidney; 19 duct 
of kidney; 20 pulmonary veins; 21 respiratory orifice; 
22 insertion of retractor muscles; 2S tentacular muscles; 
2Ji. mantle; 25 integument; 26 arteries. 


1 The under side of the head, shovring the mouth; 1 anterior 

or upper lip ; 2 lateral lips ; 3 four corrugations of the in- 
tegument surrounding the mouth; 5 triangular ap- 

2 View from above, the integument and dorsal part of the 

basal body cut open and turned back: 1 corrugations of 
the integument surrounding the mouth; 2 lateral lips; 
S buccal body; .^ jaw; 5 radula; 6 esophagus; 7 salivary 
ducts; 8 muscles of ocular tentacle; 9 muscles proceed- 
ing from the anterobasal part of the animal, and in- 
serted in the olfactory tentacular muscle; 10 muscle pro- 
ceeding from the anterobasal part of the animal to the 
mouth; 11 muscles of the olfactory tentacles; 12 muscles 
from integument to anterior part of buccal body; IS 

3 Digestive organs^ etc.: 1 buccal body; 2 esophagus; S 

salivary ducts; 4 salivary glands; 5 crop; 6 stomach; 7 
intestine; 8 rectum; 9 anus; 10 arteries, x 3. 

4 Enlargement of the under side of the upper salivary gland. 

5 Dorsal view of an adult individual. 



6 Transverse section of a specimen: 1 mantle; 2 envelop of 
the shell; 3 shell; 4, 5 pulmonary veins; 6 pulmonary 
cavity; 7 mucous part of the integument; 8 muscular 
substratum of integument; ,9 muscular peritoneum; 10 
muscular and mucous basal integument; 11 visceral 

Generative organs 


1 1 genital opening; 2 penis; 3 vas deferens; 4 spermatic 

duct; 5 retractor muscle of the penis; 6 receptaculum 
seminis; 7 free oviduct; 8 uterine canal; 9 albumen 
gland; 10 hermaphroditic duct; 11 ovotestes. 

2 Penis retracted, x 3. 

3 Penis exserted, x 3. 

4 Ovotestes, x 4. 

5 Ceca of the ovotestes, enlarged. 

6 A still farther enlargement of the ceca. 

7 A transverse section of the penis and vas deferens, x 6. 


Circulatory system, x 3 

1 1 aorta as it leaves the ventricle; 2 anterior aorta; 
3 arteries to the crop; 4 arteries to the uterine canal; 
3" arteries to the stomach, intestine and digestive gland; 
5 artery to the lower salivary gland; 6 artery to 
upper salivary gland ; 7 posterior aorta ; S arteries to the 
intestine; 9 arteries to the digestive gland; 10 artery to 
ovotestes; 11 artery to penis; 12 artery to vagina and 
receptaculum seminis; 13 artery to buccal body; 14 
artery to commissural cords; 15 arteries to tentacles; 
16 artery to basal part of the body. 



2-3 Large lateral veins situated in the integument on each side 
of the body. Only the larger veins are shown, but they 
are connected with the arteries by a fine network of 
veins and capillaries, x 3. 

4 Showing the arteries and veins of the large lobe of the 

digestive gland, x 3. 

5 1 pedal sinus; 2 lateral veins. 

Muscular system, x 4 


1 1 origin of retractor muscles; 2 principal muscular bands; 

3 retractor muscles of the ocular tentacles; 4 retractor 
muscles of the olfactory tentacles ; 5 retractor muscles of 
the buccal body; 6 muscles proceeding from the olfac- 
tory tentacular muscles to the mouth; 7 muscles pro- 
ceeding from the anterobasal part of the animal to the 
mouth ; 8 muscles proceeding from the anterolateral part 
to the olfactory tentacular muscles; 9 muscles proceed- 
ing from the anterolateral parts of the animal to the 
mouth; 10 muscles proceeding from the anterotoasal part 
to the olfactory tentacular muscles; 11 muscular fibers 
from the buccal body to the mouth. 

2 Pulmonary veins, x 4. 

3 Under side of the pulmonary cavity, x 4: i auricle; 2 ven- 

tricle; 3 pulmonary veins; 4 respiratory orifice; 5 kidney; 
6 duct or secondary ureter of kidney; 7 anus. 


Muscular system, x 6 

1 1 buccal body; 2 muscular sheath of ganglia; 3 muscles of 
the ocular tentacles; 4 muscles of olfactory tentacles; 5 
muscles arising in the basal part of the animal and 
connecting with the olfactory tentacular muscles; 6 
muscles arising in the olfactory tentacular muscles and 
connecting with the mouth; 7 muscle arising in the 
basal part of the animal, beneath the ocular tentacular 



muscles and connecting with the mouth; 8 muscles aris- 
ing in the anterobasal part and connecting with the 
muscles of the olfactory tentacles; 9 muscles arising in 
the anterobasal part and connecting with the mouth ; 11 
muscular fibers from the buccal body to the lips; 12 
muscles of the buccal body; 13 esophagus; 14 salivary 

2 Buccal body turned back to show the muscles beneath: 
1 broad oblique bands of muscles arising in the antero- 
basal part and inserted in the extreme anterior part of 
the animal ; 2 ocular tentacular muscles ; 3 olfactory ten- 
tacular muscles; 4 muscles arising in the anterobasal 
part of the animal, and inserted in the ocular tentacular 
muscles; 5 muscles arising on the under side of the 
buccal body and inserted in the lips; 6 oblique muscles 
of the under side of the buccal body; 7 retractor mus- 
cles of the buccal body; 8 retractor muscles; 9 pedal 
sinus and bordering veins. 


The numbering of the horizontal lines corresponds to that of the figures. 

The same lettering refers to the same organ in all the figures. 

Transverse sections of Limas maximus, x3. 

An outline showing the position of the sections. 

The section, figure 1, was made at the place designated by 
line 1, and so on to figure 12. 

salivary ducts; 0' salivary glands; 1 mantle; 2 shell 
cavity; 3 shell; 4 kidney; 5 heart; 6 penis; 7 arteries; 8 
receptaculum seminis; 9 uterine canal, spermatic duct 
and albumen gland; 10 crop; 10' intestine; 10" eso- 
phagus; 11 rectum near anus; 12 pulmonary vein; 13 
respiratory orifice ; 14 pedal sinus ; 15 large lateral veins ; 
16 smaller lateral veins; 17 veins contiguous to and 
parallel with the pedal sinus; 18 digestive gland; 19 
hermaphroditic duct; 20 ovotestes; 21 ocular tentacular 
muscles; 22 cartilaginous cushion supporting radula; 
22' radula. 



Nervous system 

1 supra-esophageal ganglia ; 2 infra-esophageal ganglia ; 2' 
commissural cords connecting the supra- and infra-esophageal 
ganglia; 3 buccal ganglia; 3' commissural cords connecting the 
cephalic or supra-esophageal and the buccal ganglia ; S" commis- 
sural cord uniting the buccal ganglia; 4 stomachic ganglia; 
5 nerves to the ocular tentacles; 6 nerves to the olfactory ten- 
tacles; 7 nerves to the mouth; 7' nerves to the lips and adjacent 
integument; 8 nerves to the integument of the integument of the 
ocular tentacles; 9 nerves to the anterior part of the buccal body; 
10, 11 nerves to the posterior part of the buccal body; 12 large 
nerves running to the posterobasal part of the animal ; 13, 13' 
branches of the preceding; IJf, 15 nerves from the pedal ganglia 
to the basal part of the body; 16-19 nerves from the pedal ganglia 
to the sides of the body; 20 cord connecting pedal and stomachic 
ganglia ; 21 nerve to retractor muscles ; 22 nerve to pulmonary 



1 A profile view of a small specimen of Limax maxi- 

m u s : i respiratory orifice; 2 genital orifice. 

2 The radula, profile view, x 6. 

3 The same, as seen from above, x 6. 

4 The jaw and its retractor muscle, x 6. 

5 Dorsal view of upper salivary gland, x 3 : i salivary duct ; 

2 arteries; 3 nerves; Jf artery to the stomach. 

6 Lower salivary gland: 1 salivary duct; 2, 3 arteries; 4 

nerve, x 3. 

7 The digestive gland detached from the intestine, etc. dorsal 

view, X 3. 

S The same as seen from below; the points a are in apposition 
when the gland is in its natural position: 1 herma- 
phroditic duct; 2 arteries. 




9Polygyra albolabris, showing the generative 
organs in situ : 1 genital opening ; 2 penis ; 3 vagina ; ^ 
vas deferens ; 5 spermatic duct ; 6 uterine canal ; 7 talon ; 
8 albumen gland; 9 hermaphroditic duct; 10 ovotestes; 
11 salivary gland ; 12 stomach ; 13 rectum ; IJf beginning 
of rectractor muscles ; 15 buccal body ; 16 tentacular 


1 A group of eggs, natural size. 
2-5 Various forms of eggs, x 4. 

6, 7 Transverse sections of round and oval eggs. 

8 The germinative vesicle, x 48. 

9 The under side of the germinative vesicle at the beginning 

of segmentation, x 48. 

10, 11 The ovum during segmentation as seen from above, x 48. 

12 A side view of the same, x 48. 

13 The segmented mass as seen from below, showing blasto- 

pore, endoderm and ectoderm, x 48. 

14 A vertical section of the same, showing 1 the blastopore; 

2 the archenteron; 3 cleavage cavity; 4 ectoderm; 5 endo- 

15 Cells. The dark cells are from the ectoderm; the light 

from the endoderm, x 250. 

16 Showing the endodermal cell mass surrounded by a trans- 

parent sac or wall, x 32. 

17 Showing the early stages of the formation of the foot and 

shell sac, x 32. 

18 A stage slightly more advanced, showing the beginning 

of the tentacles and shell, x 32. 

19 A stage still more advanced showing the beginning of the 

podO'Cyst at the extremity of the foot, x 32. 

20 A view of the same, from below, showing the podocyst and 

the mouth of the animal, x 32. 



This plate shows the gradual development of the embryo from the ger- 

minatlve vesicle. 

1 The germinative vesicle within the egg, natural size and x 8. 

2 Germinative vesick, x 16. 

3 Under side of same at the commencement of segmentation, 

X 16. 

4 The segmented ovum, x 16. 

5 The endodermal cell mass, Inclosed by a transparent sac or 

wall of ectoderm, x 16. 

6 Showing the transparent sac greatly developed on one side 

of the cell mass, x 16. 

7 The beginning of the development of the body form, as 

shown by a slight elevation from the cell mass, x 16. 

8 A stage slightly more advanced, x 16. 

9 The elevation is divided into two lobes, representing the 

body proper and the shell sac, x 16. 

10 The embryo within the egg, natural size and x 8. 

11 A stage more advanced than in figure 9. The podocyst is 

here plainly shown, x 16. 

12, 13 Still more advanced stages, x 16. 

14 An embryo within the egg, x 8. 

15 In this stage the tentacles are rapidly developing, the body 

and podocyst are distinct, and the development of the 
buccal body and alimentary canal has begun, x 16. 

16-19 Gradual development of the embryo. In figure 16 the en- 
dodermal cell mass has reached its greatest size, gradu- 
ally becoming absorbed in succeeding stages, x 16. 
18 The embryo within the egg, showing the same stage as in 
figure 19, X 8. 

20, 21 Ventral and profile views of the embryo within the egg, 
X 8; showing a stage more advanced than that repre- 
sented by figure 19. 



1 Showing the same stage as represented by figures, 20, 21 in 

plate 25. The podocyst in this stage reaches its greatest 
size, and in the succeeding stages rapidly diminishes in 
size, X 14. 

2 Ventral view of an embryo of the same stage as repre- 

sented in figure 1; showing the base of foot, tentacles, 
mouth, lateral lips and corrugations surrounding the 
mouth, X 25. 

3 A profile view of the same, showing the tentacles and the 

"primitive kidney" on the side of the endodermal mass, 

4 A more advanced stage, x 14. 

5 A still more advanced stage. The tentacles have begun to 

assume their adult form; the internal organs are assum- 
ing definite form; and the endodermal mass and podocyst 
are greatly reduced in size by absorption, x 14. 


1 Showing the position of the embryo within the egg just be- 

fore emerging, x 8. 

2 The same removed from the egg, x 16. 

3 A fully developed specimen. The integument is cut along 

the dorsal line and drawn back, so as to show the internal 
organs. See plate 15 for a description of the various or- 

4 An egg containing two embryos, x 8. 

5 An egg containing four embryos, x 8. 

6 The tentacles and protruded mouth of an embryo; ut su- 

perior tentacle; It lower tentacle; tni buccal mass; dp jaw 
TO retractor muscle of jaw, x 10. 

7-9 Abnormal eggs. These are of frequent occurrence, x 4. 



1 A group of cells after segmentation, greatly enlarged. 

2 A group of cells at a later stage; the larger and smaller cells 

grouped in polygonal masses, and distorted from mutual 
pressure, greatly enlarged. 

3 The cells liberated from one of the polygonal masses^ show- 

ing their true form, greatly enlarged. 

4 The primitive kidney showing the cells and their calcareous 

concretions, grea-tly enlarged. 

5, 6 Groups of cells from the position indicated by the lettering 
5 and 6, figure 5, plate 26, greatly enlarged. The latter 
containing calcareous concretions as in the "primitive 

7-13 Showing the gradual development of the shell, x 30. 
14 The fully formed shell, dorsal view, x 2. The under side of 
the shell has very much the appearance represented in 
figure 13. 

Plate I 





Mr) -W) 








^ (•> 





:! U 



Plate 3 



■ *^ 10 17 



Plate 5 

Plate 6 


\ .. , , 



1 ^^^iV, 

Plate 7 

/ U. 





5 1 


,:J# i 

/■ 1/ 


Plate 8 



I* ,11 ,1 Ji > ' >»'! 


Plate g 

Plate II 

Plate 12 

1^ ^^^ 



Plate 14 

Plate 15 

Plate i6 

Plate Tj 

Plate i8 

Plate 19 



^-— — ^-'<*'. 7 ^^^W*- 

<^' , ^t 

'M ,-N 




\rc: ]'r^ 


wmi i 



Plate 20 

Plate 21 

CO en O 



Plate 22 

Plate 23 


Plate 24 

.*•' X 



r "^^1 

■ 'Ai-i'j.y^'' 


/ y 

13 ^-TfJ;:^?=^-, 




' i. 


.^^ -*jl<^' 



Plate 25 

— CT?^' 






' ' :^.( 


i^'-M S 





Plate 26 


Plate 27 


^■„^^/t^ -**■ -'"^ ■"^' 

„^ ^■ 

^. ^Kj^gpfc- ..•><i^ 

,,^"^-^ j^^^-;. 



Plate 2E 

S?^-*ig^-^'' -«,~ 


\ ^y ] k>/jB \'*' lay 

1© K "\' '\to 

»1 /'l:^ 



>0 '^ 
)0 ^ 



The superior figures tell the exact place on the page In ninths; e. g. 262' 
means page 262, beginning in the third ninth of the page, i. e. about one 
third of the way down. 

Albumen gland of Polygyra al- 

bolabris, 257'-68'; of Limax maxi- 

mus, 28(?. 
Apparatus necessary for study, 

Arteries of Polygyra albolabrls, 

264»-66"; of Limax maximus, 280"- 

Auditory .organs, 275°-76*. 

Blood of Polygyra albolabris, 267'- 

Carnivorous hablta of Polygyra 
albolabris, 247'-49'. 

Circulatory system, of Polygyra al- 
bolabris, 262"-68'; of Limax max- 
imus, 280^-83'. 

Cryptoicus, 256', 261'. 

Digestive system, of Polygyra al- 
bolabris, 249'-54'; of Limax max- 
imus, 278^-79'. 

Direction, sense of, 276'-77'. 

Dissection, methods, 242'-43°. 

Eggs of Limax maximus, time of 
laying, 293*-94'>. 

Embryology of Limax maximus, 

Entozoa, description of a new 
species, 261*-62^ 

External features of Polygyra al- 
bolabris, 245'-46'. 

Food of Polygyra albolabris, 247'- 

Generative system, of Polygyra 
albolabris, 255'-61*; of Limax 
maximus, 279*-80*. 

Growth of Limax maximus, rate of, 

Habits, of Polygyra albolabris, 
243°; of Limax maximus, 244'. 

Hancock, Albany, quoted, 275'. 

Hearing, sense of, 275'-76*. 

Heart, of Polygyra albolabris, 264='; 
of Limax maximus, 280°. 

Kidney of Limax maximus, 283'. 
Killing and manipulating, methods, 

Leidy, Joseph, description of a new 
species of Entozoa, 261*-62=; opin- 
ion on olfactory organs, 274'. 

Limax maximus, 277'-94''; circula- 
tory system, 280*-83'; digestive 
system, 278^-79'; time of laying 
eggs, 293*-94'; embryology, 290'- 
93'; generative system, 279*-80'; 
rate of growth, 294'; habits, 244°; 
muscular system, 287'-89»; ner- 
vous system, 283'-87'; explanation 
of plates, 309-22. 

Manipulating, methods, 241»-43'. 
Methods and appai'atus, 241'; of 

liilling and manipulating, 241M3'. 
Microscope, laboratory dissecting, 




Movement of Polygyra albolabris, 

Muscular system of Limax maxl- 

mus, 287'-89». 

Nervous system, of Polygyra albola- 
bris, 268''-72'; of Limax maximus, 

Olfactory organs, 273=-75''. 
Oviduct of Polygyra albolabris, 

Ovotestis, of Polygyra albolabris, 

256''-57'; of Limax maximus, 

279", 280=. 

Pedal gland of Polygyra albolabris, 

Polygyra albolabris, 244^-77'; car- 
nivorous habits, 247'-49'; circula- 
tory system, 262'-68'; digestive 
system, 249'-54^; external feat- 
ures, 245"-46»; food, 247M9'; 
generative system, 255'-61M ba- 
blts, 243°; movement, 247'; nerv- 

ous system, 268'-72'; pedal gland, 
254"; explanation of plates, 295- 
308; shell, 244M5'. 
Pulmonary cavity of Limax maxi- 
mus, 282°. 

Salivary glands of Limax maxi- 
mus, 279'. 

Sense, special organs, 272*-77'. 

Shell of Polygyra albolabris, 244^- 

Sight, sense of, 272'-73=. 

Smell, -sense of, 273»-75'. 

Sochaczev7er, , opinion on ol- 
factory organs, 274'. 

Taste, sense of, 272'. 
Touch, sense of, 272'. 

tJterine canal, of Polygyra albola- 
bris, 258'; of Limax maximus, 

Veins, of Polygyra albolabris, 266'; 
of Limax maximus, 2S2»-83'. 

University of the State of New York 

New York State Museum 


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18 Beauchamp, W : M. Polished stone articles used by the New York 
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19 Merrill, F: J. H. Guide to the study of the geological collections of 
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20 Felt, E. P. Elm-leaf beetle in New York state. 46p. il. 5 pi. June 
1898. Frice 5 cents. 

University of the State of New York 

21 Kemp, J. F. Geology ^f the Lake Placid region. 24p. i pi. 
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22 Beauchamp, W: M. EarthenWare of the New York aborigines. . 
78p. 33 pi. Oct. 1898. Pricf 25 cents. 

23 Felt, E. P. 14th report of the state entomologist 1898. iS^P- i'- 
9 pi. Dec. 1898. Price 20 cents. . 

24 '-4-. — : , Memorial of thei life ancj . ejitomologic work of J. A. 
Lintner Ph. D. State entomologist 1874-98. 3i6p. i pi. Oct. 
1899. Price 35 cents. 

25 Peek, C : H. \ Report of the state botanist 1898. 76p. 5 pi. Oct. 
1899. Out of print. 

26 Felt, E. P. Collection, preservation and distribution of New York- 
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27 - — . Shade-tree pests in N^ew York. 26 p. il. 5 pi. May 1899. Price t,c. 

28 Peck, C: H. Plants of North Elba. 2o6p. map 12x16 cm. 
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29 Miller, G. S. jr. Preliminary list of New York mammals. i24p. 
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30 Orton, Edward. Petroleum and natural' gas in New York. i36p. 
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32 Beauchamp, W : M. Aboriginal occupation of New York. igop, , 
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33 Farr, M. S. Check list of N. Y. birds. 224p. Ap. 1900. /Wci? 25^. 

34 Cumings, ' E. R. Lower Silurian system of eastern Montgomery 
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35 Rips, Heinrich. Clays in New York: their properties and uses. 
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36 Felt, F'.'P. i6th report ofthe state entomologist 1.900. ii8p. 16 pi. 
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37 ' Catalogue of injurious and beneficial insects of New York 

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38 Miller, G. S. jr. , Key to the land mammals of northeast 
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39 Clifrke, J: ,M., Simpson, G: B. & Loomis, F: B. Paleontologic 
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40 Simpson, G:B. Anatomy and physiology of Polygyra albolabris 
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41 Beauchamp, W: M. Wampum and shell articles used by New Yprk 
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43 Kellogg.'J. L. Clam and scallop industries of New York. 36p. 2 pi. 
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44 Ries, Heinrich. Lime' and cement industries of' New York. Inpressiil^ • 

45 Grabau, A. W. Geology and paleontology of Niagara falls and vi- 

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46 Felt, E. P. Scale insects of importance and a list of the species in 
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