48.M5
laboratory guide in elementary zoology

Cornell University

Library

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http :/Awww.archive.org/details/cu31924003401035

soyiny ey Aq peydesszojoyq
LSHUN GNV JAO”d FATLANL

A LABORATORY GUIDE

ELEMENTARY ZOOLOGY

WILLIAM FAIRFIELD MERGER, Ph. D.

Professor of Biology, and Geology
Ohio University, Athens, Ohio

1909

THE ATHENS PRINTERY
ATHENS, OHIO

s

Entered according to Act of Gongress, in the year 1909,
by William Fairfield Mercer, in the office of the Librarian of
‘Gongress; at Washington.

INTRODUCTION.

This guide is designed for use in my own classes, and
it sets forth an outline of the work done in Zoology. No
claim is made as to the originality of the subject matter
except in the method of presenting it, and the order in
which it is given... It has been in use in our laboratory
for several years in mimeographic form. Type forms are
taken of the different groups, and carefully studied. The
classification of animals conforms to that -of the “Manual
of Zoology” by Parker_and Haswell, which is used_as a text
for class work. Any other good text may be used. All
instructions for the use of apparatus, etc., are left to be
supplied by the teacher in charge. , ,

Acknowledgment is here due Dr, W. F. Copeland, J. BE
McDaniel, Ph. M., and A..A, Johnson, Ph, B., former assist-
ants of mine, and my present assistants, J. A. Badertscher,
and C. E. Hayden, for many valuable suggestions in the
working. of the manual before going to print.

—The Author.

=,

Ohio University, January, 1909,

UNICELLULAR ANIMALS

PHYLUM PROTOZOA
1 Rhizopoda
1. Amoeba

ANATOMY—The amoeba is so transparent that it is
difficult to find without a great deal of care and some
experience in the use of the microscope. After a good
specimen is found note size, shape, and structure. Can it
be seen without the aid of a microscope? Bxamine other
specimens and compare as to size. What is the shape?
‘Note any change in form that ‘may occur. If there are
any projections they will be called pseudopodia. Is the
number of pseudopodia constant? Are they in the same
position at all times? What is the meaning of the term
pseudopodium? Sketch the animal in five different posi-
tions. Is there any difference in- appearance in any. part
of the animal that would seem to indicate a differentiation
in structure? If so an outer clear area wiil be seen, the
ectosarc. Is this seen all over the body? Why? The
inner granular portion is Known as the endosarc. How
does the quantity of this compare with that of the ectos-
arc? Is the endosare uniform throughout? Do the gran-
ules always occupy the same position? A denser portion, -
the nucleus, will be seen in the endosarc, What is its size,
shape, and position? Are these all constant? Do they
vary in different specimens? If the nucleus is not visible
run a drop of dilute iodine under the cover. What effect
does this have upon the entire dnimal? If iodine has been
used the slide must be carefully cleaned and a new speci-
men found for the completion of the work. Look for clear
areas in the endosare. If one is found that varies regularly
in size it will be called the contractile vacuole. How many

A MANUAL OF ZOOLOGY 5

are found? Make a careful: drawing to illustrate all the
structures of the amoeba,

PHYSIOLOGY—Describe the movements of the ani-
mal. Does the body change in shape as the animal pro-
ceeds? How does the movement seem to be brought
about? How are the pseudopodia formed? Note the
method of taking food. If your specimen is not taking food.
add a little ground carmine to the water under the cover.
‘The animal will take this as food. What would be the natur-
al food of the animal? The activities of the animal must
necessarily produce waste matter. Are there any organs
of excretion? Has your specimen cast off. any waste mat-
ter at any time during your study? Remove the cover or
mount a new specimen without a cover. While looking at
the specimen touch it with a bristle or tap the slide. What
effect does it have? Warm the slide to 45 degrees C.
Note the effect. Touch the slide with a glass rod heated
and note the effect. The amoeba reproduces by. the simple
method of fission. Somé one in the class may be fortunate
enough to find a specimen in the act of dividing. If so the
attention of the whole class should be called to this
specimen. Is there any way of knowing which is the
parent in this simple method of reproduction?

ll INFUSORIA
‘ 1. Paramoecium :

ANATOMY—Compare this form with the amoeba as
to shape and activity. What is the shape of this animal?y
Is it constant? If it changes compare with the change in
the amoeba.” Is re any way of determining an anterior
and a posterior end? How does the paramoecium compare
in size with the amoeba? Can you account in any way
for its permanency in shape? Is there a cell wall? Does
it extend over the entire surface? Is there an ectosarc, an
endosare, a contractile vacuole, or a nucleus? Compare
in each case with the amoeba. In the paramoecium two
nuclei may be found: a large one, macronucleus; and a
small one near the large one, micronucleus. Look for cilia.
Are they all over the body? Are they all alike? Kill
a specimen with 1 per cent osmic acid. Study the cilia.
Look for a row of striations under the cuticle, trichocysts.
What is the position and shape of the mouth? Is it con-

6 A MANUAL OF ZOOLOGY

stant? Compare with the amoeba. Look ‘for a tube, the
oesophagus, leading from the mouth to the interior. Are
there any cilia here? What seems to. be their function?
During the study of a specimen it may be seen to eject
waste material through an opening in the body wall, the
anus. Is its position constant? When is it seen? Note
the food particles filling into the spaces as the animal
gathers food. Are these food vacuoles constant in number
and size in all specimens? Make a large drawing showing
all structures of the paramoecium.

PHYSIOLOGY—What are the motions of the body as
awhole? What are the organs of locomotion? Are all the
motions of the body caused by these organs? Study the
motions of the cilia. Are they all used for the same pur-
pose? Apply a drop of 1 per cent acetic acid and note the
effect on the trichocysts. From this effect, what would be
considered the function of the trichocysts? Study the
contractile vacuole in a live specimen for several minutes
and note any peculiarities in the movements of this organ.
How does the motion of the food vacuoles compare with
the motion in the contractile vacuole? How does the
paramoecium take its food? Compare with the amoeba.
Note the formation of the food balls in the food vacuoles.
_ As they move about the body note any change in the size
of the balls. How is this change accounted for? Stain
with dilute iodine and ascertain what the paramoecium
eats. Iodine stains starch blue and .albuminous substances
brown. Feed some live specimens some ground carmine
as in the amoeba. Is there any concert of action on the
part of the animal? Can the next movement be anticipated
in observing him? Is there anything about the paramoe-
clum that would lead one to think that it has any special
senses? Darken one side of a dish containing large num-
bers of the animals and leave it four or five hours in a
light place. Examine with a hand lens and find which side
of the dish has the more of them. The paramoecium has
two methods of reproduction by fission and by conjugation.
Different specimens may be found representing each of
these methods. Watch the process through in either case
and observe the method in detail. Make a drawing’on a
large scale of the animal.

A MANUAL OF ZOOLOGY
2. Vorticella ©

Review the directions for the paramoecium and answer
the same questions in reference to the vorticélla as far as
they apply. Note the difference in shape. It will be noticed
that this animal has a stalk and is regularly fastened to
some support. What is the structure of the stalk? Study
the peristome (rim of the body), the disk (within the peri-
stome), myophan layer (striated base of body), and the
vestibule (entrance to the gullet). Make a drawing on a
large scale showing all parts. From the movements what
would you consider the function of the stalk to be? Is the
body always in connection with the stalk? If not, there
must be some free swimming forms. In addition to the
methods of reproduction’ in the paramoecium the vorticella
has another method that is called encystation. Look for
specimens of this type. Make a drawing representing all
the stages of reproduction.

MULTICELLULAR ANIMALS

PHYLUM PORIFERA

PORIFERA (SPONGES)
1. Ascon Sponge
Leucosolenia.

This is a marine form found abundantly along the New
England shores fastened to seaweed, submerged wood, etc.,
just below low tide mark. Note the difference in size of
the specimens submitted for. examination. Study- them
with the hand lens. Note the cylindrical sponge body. Do
the two ends differ? Note the opening at one end, the
osculum. Press the sponge lightly. Notice the flexibility
of the wall... Note the buds on the larger specimens. Do
the buds have oscula? Carefully cut a sponge from the
osculum to the base. Lay the cut specimen open in water
with the cloacal surface up. Does this chamber communi-
cate with that of the buds?

Place one half of the specimen where it will dry, and
the other half in borax carmine, from one to several hours,
While the first specimen is drying draw a cluster of
sponges, illustrating all the points considered up to this
time. Examine the cloacal surface of the dry specimen

8 A MANUAL OF ZOOLOGY

with the low power of the microscope. Note the multi-
tude of small needle shaped bodies, the spicules. How
many distinct forms appear? In what plane do al] the
prongs of the spicules extend? ‘By careful manipulation
a fourth prong on some of the spicules will be seen to
project into the cloacal cavity.

‘Remove the specimen from the stain, wash in acid
alcohol, 95 per cent, and absolute alcohol, clear, and mount
in balsam, with the cloacal surface uppermost. Do not
press the cover glass down. Use the low, and the high
power of the microscope. A layer of cells whose nuclei
are very prominent is above (inside) the spicules, the
entoderm. Note the extent of this layer of cells. During
life these cells are supplied with flagella and collars. 'The
activity of these flagella keeps a current of water moving”
from the outside through minute pores in the wall into the
cloacal chamber and out through the osculum. The pores
may be seen as small clear spaces between the spicules.
The mesodermal cells are located outside of the entodermal
layer. This layer is not continuous, the cells are scattered
somewhat. The ectoderm is not easily seen but is located
outside the mesoderm. ‘

Make a drawing representing all the points mentioned
above.

Many of the larger specimens prepared as above will
be found to bear reproductive cells. They will be seen
as large, deeply stained cells in the mesodermic layer.
Two kinds will be noticed, the male and the female. The
former, spermatozoa, occur in spheres, each sphere con-
taining hundreds of sperm cells. The nuclei of the sperm
cells are much smaller than those of the mesodermal cells
which give the spheres a dotted appearance. The spheres
themselves are quite large. The ova, or egg-cells, are pro-
vided with but a single nucleus. Sometimes a nucleolus
will be found imbedded in the nucleus. The egg cells are
amoeboid, seldom regular in shape. Make a drawing rep-
resenting the two forms of reproductive cells,

Prepared slides of cross, and longitudinal sections will
be provided. Make a drawing to represent the crosg,
section. ’

,

A MANUAL OF ZOOLOGY 9

2. Sicon Sponge (Grantia)

Notice size, shape, and color. Is there any suggestion
of a free and an attached end? How do the two ends differ?
Are all the specimens the same shape? Look for projec-
tions on the sides of the different specimens. If there are
any it is probably the beginning of buds (a process of
reproduction). Measure several specimens and compare
them. Is there any suggestion that these sponges »ver
may become of commercial value? Look for the osculum
(the opening at the free end). Note the spicules about
the osculum. Do they differ in any way from the spicules
on the sides of the body? Is there more than one osculum
on the specimen? If so, where located? Cut a budded
specimen lengthwise and study the body cavity. How far
does it extend? What relation does the cavity of the bud
have to the cavity of the main part of the body? How
does the thickness of the body wall compare with the
diameter of the cavity of the body? Study a longitudinal
section with the low power. Note the canals leading into
the body cavity from the outside. Are the openings to
these canals.protected in any way? Compare the two-ends
of the radial canals in this respect. A slide of spicules
will be supplied. Study them and decide how many forms
there are. Treat some with dilute H Cl. What is the
result? What is the composition of the spicules? Stained
sections, both longitudinal and cross, will be supplied.
Study them and make out the several layers of cells and
the relation of the spicules to them. Try to find out if the
radial canals lead directly from the outside to the body
cavity or cloaca. Make drawings to show general appear-
ance of the animal, also of longitudinal, and cross sections,
both with and without the microscope. Compare the
fresh water sponge (spongilla) in every respect with the
Grantia.

f

3. Toilet Sponge

Study several specimens and detect any likenesses or
differences 'in the:specimens. What part of the animal is
being studied. Note size, shape, color, and texture. Are
there any suggestions as to why sponges will take up
water? What is there about this sponge that is similar to
the grantia? What is different? Point out the osculum or

10 A MANUAL OF ZOOLOGY

oscula on the specimen in hand. ,Pull out a small piece
and study the structure under the low and the high power.
Make a drawing of the specimen as a whole. Make a
diagram to illustrate the structure as seen under the high
power, es

PHYLUM COELENTERATA

|} HYDROZOA
1. The Fresh Water Polyp or Hydra

Examine several specimens as to size, shape, and
color, Decide whether the animal is free to move about
or not. If it moves about, what is its method? Are there
any specimens that seem to be double? If so, are there
any suggestions as to how this might occur? Are. all
specimens the same color? Find the following parts of the
body: The foot (attached portion); the body proper; the
body cavity (enteron); the mouth, and the tentaéles. What
is the relation of the mouth and*the tentacles? Study
several specimens for the number and the variability of the
tentacles. Make a drawing on a large scale showing all
the parts studied thus far. Watch the Hydra in a jar for
some time turning the jar so as to vary the light. Decide
as to the method of locomotion and the changes in shape,
and length of both body and tentacles. If the hydra are
not inclined to move about they may be induced to do so
by suspending a small piece of meat in the water by means
of a thread quite near the animal. - To observe the method
of eating, place several good specimens in a watch glass |
and with them a few small bits of meat. Describe care-
fully what is observed. Is there any evidence that other
things have been eaten? If so, what? Describe the action
of the hydra when irritated. Test the effect of light upon
the hydra by covering one side of a jar containing several
specimens. Are there any evidences of co-ordination in
the movements of the hydra? Study live specimens and
stained sections under the high power. Determine the
extent of the stomach cavity or enteron. Is there any
opening (anus) for waste matter to leave the body? The
body wall will differentiate into three layers, two of which
are cellular; the outer (ectoderm), the inner (entoderm);
the. middle or supporting layer (mesogloea) is not cellular.

A MANUAL OF ZOOLOGY 11

Cnidoblasts or thread cells will be found among the cells
of. the ectoderm. They contain nematocysts or capsules
in which is a coiled thread. The cnidoblasts are terminated
by a sharp point, the cnidocil or trigger hair. Are-these
cells uniformly distributed over the tentacles? Study the
ectoderm and the entoderm for any difference in shape
or size of the cells. What is the extent of the entoderm?
Make a drawing of a cross section through the body and
one through a tentacle. Does the hydra have any special
sense organ? Run a drop of dilute acetic acid under the
cover and note the effect on the nematocysts. Find a
specimen that is budded and see what relation exists
between the body cavity and the bud cavity. Make draw-
ings to show parts referred to above. Under favorable
conditions ovaries and testes may be found on the same’
specimen. The former are located near the base of the
animal, the Jatter as small knob-like swellings near the
tentacles. Spermatozoa may be demonstrated by crushing
a specimen under the cover. If found, describe them-

2. Campanularian Hydroid

Alcoholic material as well as permanent stained
mounts will be furnished. If possible get a specimen
attached to some support. Examine the attached end,
‘hydrochiza; the stalk, the hydrocaulus; and the branches
with the hydranths. Would this cluster be considered a
colony or a single animal? Note any differences in the
hydranths. How are the branches arranged? Find a trans-
parent covering, the perisarc. What is its extent? Is there
any difference in arrangement at any point? Under this
layer find the fleshy portion, the coenosare. Compare with
the hydra for the layers: the entoderm, the ectoderm, and
the supporting layer. What is the extent of the body
cavity? Look for two forms of zooids: the feeding, and the
reproductive zooids. Note the extent of the perisarc in
the former. Find the nematocysts (lasso cells) on the
tentacles. How many tentacles are there? Compare them
with those of the hydra. Note the mouth at the outer end,
or the manubrium. How do the reproductive zooids com-
pare with the ones just studied? Look along a central
stalk (blastostyle) for the medusae which are finally to
be shed. Make an enlarged drawing of the entire animal,

12 A MANUAL OF ZOOLOGY 7

representing the forms of zooids. Can a feeding zooid be
distinguished from a reproductive hydranth at this stage?
From the study of the hydra one can get a good idea of
the life process in this form. Several other forms of
hydroids will be furnished for study and comparison.

PHYLUM ECHINODERMATA

Asteroidea (Starfish)

What is the general shape? Are there any variations
in different specimens? The under surface is known as
the oral, and the upper surface as the aboral surface.
Make drawings of ss of both surfaces.- Whence the common
name of the animal? Examine and compare several speci-
mens for size and color. The central part of the body is
called the disk. Find the madreporic body on one side of
the disk. The bivium is formed by the two rays that touch
the madreporic body. ‘The other three form the- trivium.
The anterior ray is the one opposite the madreporic body.
Note any differences in any of these rays. At this point
soak a medium sized specimen in dilute KOH for a. few
hours and carefully clean the flesh off with a brush. This
will leave the skeleton which will be left to dry for future
use. ‘ °

Examine the spines as to shape, and size. Are they
movable? Note any differences in the spines around the
mouth (Mouth Papillae). Remove a small portion of the
skin and examine it under the microscope. Find the
ciliated columnar epithelium. The aboral tentacles will be
found at the base of the spines. Around the mouth find a
membrane, the peristome. On the oral side of the rays
extending the entire length will be found the ambulacral
grooves, which contain the ambulacral feet. Pull off a foot,
make cross and longitudinal sections, then examine each
carefully for structures. Note the disk on the distal end,
and the opening through the center. Note the arrangement
of the muscles. Carefully pull off some of the feet and find
a membrane stretched across the deeper part of the groove,
Above this will be found the radial water tube. A demon-
stration of the water vascular system will be made on
injected specimens.

A MANUAL OF ZOOLOGY 13

It will be necessary to study well prepared cross sec-
tions of the rays in order to demonstrate the nerve and the
blood vessels that run along with the water vascular
system. Make a drawing of_a cross section of a ray. Note
the eyes in the ends of the rays. Examine for size, shape,
and color. Are the eyes protected in any way? At the
base of some of the spines branched jaw-like projections,
the pedicellariae, may be found. These are best seen on
sections. Study the skeleton already prepared. Are ail
the ossicles arranged alike? Cut across one of the rays.
The ambulacral ossicles are found forming the roof of the
ambulacral groove. What is the relation of the ambulacral
pores to the ossicles? A single row of ossicles just outside
of these form the inter-ambulacral ossicles. Note that these
ossicles bear movable spines. In the middle of the floor
of the ray will be found the vertebral ridge. Of what is
it formed? Remove the disk. The mouth opening will
appear. Note the partitions between the rays, inter-radial
partitions. ‘ In. these find the reproductive orifice. Treat
some of the skeleton with dilute HCl and note results.
From the effect of the HCl, what is the chemical composi-
tion of the ossicles? By means of a pair of scissors cut
a slit from the tip of the rays of the trivium along the
sides of the dorsal surface. This must be done with
care so as not to injure the organs underneath. Turn back
the cut portion to the disk. When this is done the diges-
tive system can be seen. Note a thin membrane, the mes-
entery, which holds the large greenish bodies (hepatic
coeca) to the dorsal surface as it is turned back. What is
the size, the arrangement, and the attachment of the he
patic coeca? Demonstrate the tube or tubes, that lead ~
from it to the stomach immediately under the disk. Note
the two portions of the stomach: the central cavity; the
cardiac portion; and the pyloric portion or pouches, that
extend into each of the rays slightly. From the structure
of the mouth and stomach what would be the conclusion
as to the kinds of food adapted to the starfish? In some

specimens the cardiac portion may be foynd protruding
from the mouth. ‘What ‘does this indicate? What is the size
and extent of the oesophagus? ‘The retractor and the pro-
tractor muscles of the stomach will be seen as white shin-

es

14 A MANUAL OF ZOOLOGY

ing strands. Note the number and exterit of each. It will
require careful work to demonstrate the short intestine
leading from the top of the stomach to the anal opening in
the disk. Look above the stomach for the respiratory tree
attached to the disk. Make a drawing of the digestive ap-
paratus. In fresh specimens the ovaries are pinkinsh, and
the testes are yellowish white; both will be found in the
axis of the rays. Settle whether both appear on the same
specimen. Where do they open?

“ - The hepatic coeca have been removed. Under these
and on either side of the vertebral ridge, the ampullae or
water sacs are found. ' Study injected specimens if pos-
sible. Tear one open. What is its structure? Press on the
ambulacral feet. What effect has this on the ampullae?
Are they connected?

Now carefully remove all the digestive organs of the
trivium, including the stomach. Notice the stone canal
leading down from the madreporic plate. Around the stone
canal notice a thin membrane, the pericardium, which con-
tains the supposed heart. Before tracing out the stone
canal, remove the peristome and note the following: the
circum-oral water. tube; the potian, and the racemose vesi-
cles. There. is one..less racemose ‘than polian vesicle.
Now trace. carefully. the stone canal and account for the
difference in number .of the vesicles. Make @ drawing. of
the water vascular system.

ec respiratory” system may be demonstrated: by show-
ing the connection of.the tentacles: of. the aboral surface
with the body. cavity. Small-openings, in the roof of the
rays lead to the tube-like tentaeles. Study sections to help
decide this. .-. - 5
' Demonstrate the nervous system.by. studying with a
hand lens and alsa by the use of the microscope. The cir-.
cum-oral.nerve ring. ean be traced throughout in a gross
way, .but the radial nerve.will need the microscope and
well annie ‘sections for demonstration. .

_ PHYLUM ANNULATA ©

on Lumbricus (Earthworm).
“Have at ‘hand living specimens, as ‘well as specimens
ger =

pie¥erved in aleohol or formalin. “The 3 ‘tigsues in the pre-
served specimens ‘will be ‘harder, ‘and for that” reason are

A MANUAL OF ZOOLOGY 15

better for morphological work. Study specimen for a
right and a left side; a head and a tail; a ventral and a
dorsal surface. How are these details determined? Note
color. Would its mode of life suggest any cause for the
color? Into how many regions can the body be divided?
Note the number of segments in each. The firmest part of
the body will naturally be the most muscular. Which .
division is most muscular?: Are the segments all alike? If
not, where do they differ? Look for a protective covering
(exoskeleton). Are there any special sense organs?~ Are
there any jointed appendages or legs? Make an outline
drawing of the first two divisions and put _in the exact
number of segments or or somites. The I light colored thick-
ened division is called the” ‘Girdle or clitellum. Note the
number of segments in it, and whether they are complete
rings or not: In numbering the segments from the ante-
rior end, where do the segments of the girdle belong?
From a preserved specimen strip off a little cuticle. Note
its color and texture. Mount.a small piece in water arid
study the structure with: the high power. Note the striae
and their direction.

By passing the thumb and finger over the sides of the
animal, sharp projections or setae will be detected. ‘Study
with a hand lens and determine the direction and number
in each segment. -Note whether this direction is constant
throughout the whole length of the animal. With forceps
pull out a seta and study it with low power. Draw a seta,

The prostomium is a projection.on the extreme anterior
end of the animal, ventral. to which: the mouth will bé
found. In-numbering the segments the prostomium must
not-be counted. Note the anus at the extreme posterior
end. The dorsal: pores may be demonstrated by peeling off
the cuticle and examining it with the. hand lens. - How
many are there:on each segment? - Are the segments: alike
in this respect?. Look for a pair of openings external to
the. ventral setae on the fifteenth segment; the opening of
the sperm ducts. - Look for another--pair in similar posi-
tion of the -fourteenth segment; ‘the openings of the ovi-
ducts. Two pairs of openings will be found in line with
the outer. setae between segments 9 and 10, 10-and 11, one
pair in each groove; ‘the openings of the seminal recep-

16 A MANUAL OF ZOOLOGY

tacles. Draw a ventral view of the anterior half, locating.
the he openings “yéferred. to above. The capsulogenous glands

will be seen to vary somewhat on segments 9 to 11 or 8
to 12, on the ventral surface. Does the number of seg-
ments containing the glands vary in different specimens?

Pin a large specimen out straight, dorsal side upper-
most. Cover with water. With fine pointed scissors cut
through the body wall along the mid-dorsal line. Note the
membranous partitions, the septa. Cut these away and
pin the specimen out in the tray. The tube extending
through the body from the anterior to the posterior end
js: the digestive tract. Do the septa referred to above ex-
tend entirely across the body? Observe that the general
formation of the body is‘a tube within a tube. The outer
tube is known as the body cavity. Study a cross section of
the earth worm and find the structure of the body wall.
Note the layers of muscle fibers. In what direction do
these fibers extend?- Open the body cavity of a live speci-
men after giving it chloroform. Note a colorless fluid, the
peri-visceral fluid. Examine some of this fluid with the
microscope under both the low and the high’ power. Cells,
colorless corpuscles, like the amoeba, will be found floating
in the colorless fluid. Does the fluid_coagulate when ex-
posed to the air? What relation do the septa have to
the constriction between the segments of the body? The
digestive system referred to above is divided into several
parts. The first two or three segments are occupied by
the buccal cavity. Note the shape and how it is fastened
‘to the body wall. Following the buccal cavity is the
pharynx, How is this cavity separated from the first
cavity? ‘Note size, shape, and extent. Find the muscles
that hold it in place. ~ Leading from the pharynx is the
oesophagus. How far does it extend? Are there any vari-
ations in its size? The calciferous glands are located in
the 11th and 12th segments. From their position and con-
nections what is their probable use? Examine some of
the fluid in them under the microscope. What’ is found?
Treat some of the gland in a test tube with HCl. Explain
results. In about the 16th segment will be found a thin
walled, sac-like expansion of the alimentary canal, the

A MANUAL OF ZOOLOGY 17

crop. What does the crop contain? Make a drawing_of

some of the contents under th the microscope. Just posterior

to the crop-will be found the gizzard. Compare with the

crop. Leading from the gizzard will be found the stomach-

intestine. The yellowish mass of cells on the dorsal sur-

face of the intestine were formerly supposed to have the

function of a pancreas, but now they are supposed to be

connected with the process of excretion. Cut through the

intestine a little to one side of dorsal line and find a

longitudinal fold, the typhlosole. Examine the contents of

the intestine in the posterior region with the microscope,

and compare with that of the crop. Make an outline draw-.
ing of the body laid open on the he mid-dorsal line and locate _
carefully all parts of the digestive apparatus in their.
proper segment or ‘segments. -

-Carefully clean a live specimen and look for circula-
tory system. The dorsal blood vessel may be seen as a red
line under dorsal surface. Carefully watch for pulsations
jn this vessel. By killing a specimen in alcohol the fol-
lowing vessels may be worked out under favorable condi-
tions (the name will give the location): the circum-cesoph-
ageal blood vessel; the supra-neural blood vessel; the
lateral oesophageal blood vessel. By the use of two pairs
of fine-pointed forceps, a portion of a blood vessel may be
removed without the blood getting out. Place this under
the microscope and study the blood. What is its color?
Are there corpuscles? How do they compare with those
of the body cavity? Account for the color of the blood.
Does it coagulate upon exposure?

To study the nervous system, remove the alimentary
canal, from the pharynx back. Dorsal to the oesophagus
the supra-oesophageal ganglia will be found. Leading ven-
trally from these ganglia on either, side of the oesophagus,
white threads, circum- -oesophageal commissures, may be
found, joining. the ventral nerve cord. What is the extent
of the. ventral nerve cord? Look for ganglia on the ven-
tral nerve cord. What is the relation of the ganglia to
the segments of the body? Make a diagram of the nervous
system. "

18 A MANUAL OF ZOOLOGY

~ .The excretory system is represented by a pair of
organs, nephridia, in each segment except the first three.
With the low power find the opening in the septum, and to
the outside. Are both ends of the nephridial organ in the
same segment?

The reproductive system is represented by the seminal
vesicles, the testes, the ovaries, and the spermathecae. In
the segments 9 to 12 find the large pouch shaped bodies
(seminal vesicles). How many pairs are there? Note a
difference in size. Remove the roof of the median vesicl&
and find the testes inside the vesicle. The sperm cells are
shed into the vesicles in an immature stage and under;
their maturation there. The tubes leading from _ the
vesicles unite to form the vas-deferens, whose opening is
on the thirteenth segment. Look in segment 13 near the
septum between that, and the 12th segment for small
rounded bodies, the ovaries. The oviducts pass through
the septum and open on the 14th segment. The sperma-
thecae, small globular bodies, are found in the 9th and
10th segments. Study a live worm, noting all the move-
ments. Place some on a smooth surface and others on a
rough surface. Note any differences in their movements
on the different surfaces. Place some leaves on the sur-
face of the dirt in a box containing earthworms and leave
them several days. . Note from day to day any change in
the position of the leaves. Account for the same.

PHYLUM ARTHROPODA

Crustacea
Lobster or Crayfish.

The laboratory guide is especially adapted to the lob-
ster, but will ‘apply in general to. the crayfish. With
specimens before you study the general shape. How does
it differ from anything studied before? . Note the head
' covering, exoskeleton, Look for bilateral symmetry. Why
is this animal called an arthropod? Note that the body
proper is differentiated. How many disttact regions are
found? How does the ariterior region, the: “cephalothorax,
differ from the posterior region, the abdomen? How many
segments are found in the abdomen? How are the seg-
ments joined? Is there any suggestion of a joint? If so,

A MANUAL OF ZOOLOGY 19

what kind of a joint? Note any differences in the different
segments. On what abdominal segments are appendages
(swimmerets) found? Note the tergum, the dorsal por-
tion of a segment; ‘the sternum, the ventral portion; the
epimeron, the latero-ventral portion; the pleuron, the down
growth of the sides. Note the parfs of an appendage; the
basal portion, the protopodite; the portion attached to the
outer margin of the protopodite, the exopodite; that part
attached to the inner margin, the endopodite. Make a draw-
ing to represent a lateral view of a segment with its ap-
pendages.——~—
Describe the cephalothorax from above and from the
side. Are there any traces of segments? The cervical
‘groove divides this region into a cephalic and a thoracic
region. The branchio-cardiac grooves extend backward
from the cervical groove. The heart lies under that por-
-tion of the carapace bounded by these grooves. Note the
rostrum projecting in front. Describe it as to motion,
appendages, size, and color. Examine the ventral surface
of the cephalothorax. Are there any evidences of seg-
mentation? With scalpel handle force out the margin of
the carapace, the branchiostegite, and notice a chamber
here called the branchial chamber, or gill cavity. Is there
any suggestion here of segmentation? Compare with -a
single segment in the abdomen.
The last segment of the body is known as the telson.
Describe and draw it after observing as to its appendagesr
form, étc. Note the anal opening on the - ventral side.
Beginning with the posterior pair of appendages disartic-
ulate them on the right side of the abdomen, by cutting.
through the articular membrane with a sharp scalpel.
This will require care in order to get them clear from the
body and also entire. Study each appendage and note
all the parts referred to above. In addition note that the
protopodite consists of two segments: the coxopodite, the
basal portion; the basipodite, the distal portion. What
makes up the tail fin? Lay.the-appendages-down_in order
with their ‘posterior face 2 uppermost and make drawings
of same numbering tt them “4 “in ¢ order of segments.. Remove

the thoracic appendages in like manner, but study them
as you proceed. Examine the last thoracic appendage and

20 A MANUAL OF ZOOLOGY

note its direction, Has it an exopodite? Note the male
genital aperture. On what segment does 1t open? Make
a drawing of this , appendage. Carefully remove the next
“appendage and compare it with the one just studied. Does
it have a gill? An epipodite? In female specimens of
lobsters, note the receptive apparatus near the base of the
coxopodite. Make a drawing ¢ of this appendage. Remove
the next appendage ‘and compare with the one just studied.
How does the distal end differ from the other? Note the
female genital pore in the coxopodite. Draw_as above.
Compare the next appendage in every respect with the
ones just studied. Remove the.great chela. Compare with
the other appendages and with each other on the same
and different specimens. Is the distribution of hairs on
both chelae alike? What differences are found? Note the
teeth, are they alike on both jaws? Remove the next
appendage; the third maxilliped or foot jaw. Compare
with the great chela. Remove the next two appendages,
the second and the first maxillipeds. In a review of all
of the thoracic appendages note the two groups into which
they naturally fall. The next appendages may be called
the head appendages. Remove the Aiext one, the second
maxilla. Are there any. modifications? The large plate
like expansion is known as the scaphognathite. Remove
the next appendage, the first maxilla. Compare with the
preceding. Draw each of the - e maxillae. The mandible
is the next appendage. Note ‘the “palpus, the’ metastoma,
and the labrum. What is the direction of the mouth open-
ing? Remove the next two appendages, the antenna and
the antennule. At the base of the antenna note the open-.
ing of the green gland. Examine the antennule for the
opening of the auditory organ. Compare these two ap-
pendages in every respect. The eyestalk is sometimes
called an appendage. Make a review of all the appendages,
noting any differences or likenesses.. Decide as to- the
advantage of each to the animal... What constitutes the-
boundary of the gill chamber? The gills may be classed
as podobranchiae, arthrobranchiae, and pleurobranchiae,
What is the basis of this classification? How many of
each of the classes of gills are there? Study a gill in
water for its structure.. ‘Some-of the. gills referred to

A MANUAL OF ZOOLOGY 21

above are rudimentary. Give reasons for calling them
such. _Make a drawing of a gill. Note in general the
exoskeleton. Boil a piece of the exoskeleton. ‘Place HCl
upon another piece. What is its composition? Remove
one of the eye-stalks. Study the surface of the eye. Note
on the cornea, the flat areas, or facets. What is the shape
of the facets? Make a longitudinal section ,of the eye
stalk and all. Study with low power. “Note ‘the spindles,
the crystalline. cones, the optic ganglion,’ and the optic
nerve.

By the use of a bristle or pointed instrument find the
opening of the auditory organ among the setae on the
basal joint of the antennule. Now cut away the under
side of the joint and find a transparent sac, the auditory
sac. Study carefully with and without the microscope.
Study the contents of the sac for sand-like grains, the
otoliths. Note also the auditory hairs. The olfactory or-
gans consist of setae on the endopodite of the antennule.

With strong scissors cut through the exoskeleton on
-the sides from the telson to the rostrum. Carefully lift
it off beginning at the abdominal segments. Directly un-
der the shell find the epidermis. Notice how it is attached.
On either side of the mid-dorsal line of the abdomen
directly beneath the epidermis find the extensor akdo-
minis muscle. Note its origin and its insertion. To
what are these muscles attached? Remove them. Find
the levator abdominis muscle, whose origin is on the cara-
pace just above that of the extensor abdominis. Find
its insertion. ‘The contraction of these muscles will pro-
duce what motion? The great muscle now seen to fill
the greater part of the abdomen is the flexor abdominis.
A deep groove runs through the middle of it containing
the superior abdominal artery and the intestine. As far
out to the side as possible cut these arteries, also cut the
intestine in front of its dilated end, and turn both back
‘to one side. Now work the muscle out of the shell, being
careful not to injure the nerves underneath, Find origin
-and insertion of the muscle. What motion does this muscle
-produce? Why is it so large? The adductor muscle of

the mandible has its origin on the carapace in front of
tha earvieal croanve. It is a fan-shaned muscle ending in

22 A MANUAL OF ZOOLOGY

a long tendon extending obliquely downward to its inser-
tion on the mandible. What motion is given to the man-
dible by this muscle? Look for small muscles extending
to the antenna.

‘Remo'vwe the great chela from the body. Note the
muscles of the basal joints. To what are they attached?
With a pair of bone forceps cut around the edge of the
pincher and lay off the exoskeleton on one side. Note
the muscle contained in the cavity. Carefully dissect
away the muscle and find its origin and its insertion.
Note the central tendon and the direction of the muscle
fibers. What motion does it produce? Notice another
muscle just opposite this one and demonstrate its motion.
Why should one be called the adductor and the other the
abductor?’ Which is which? Study the muscle teased out
in normal salt solution. Stain and note results. Draw.

At the anterior end of the superior abdominal artery,
find the pericardial sinus. Note its shape and its size.
Cut through the mid-dorsal line, fold the parts back, and
find the heart. Note its size and shape. How is the heart
fastened to the sinus? ‘Look for openings into the heart
on the dorsal, the lateral, and the ventral surfaces. How
many are found on each? What connection ‘does the
superior abdominal artery have with the heart? The
ophthalmic artery originates from the anterior end of the
heart. Trace it towards the head. Does it have branches?
The antennary arteries leave the heart, one on either side
of the ophthalmic artery. Branches from these arteries
supply what organs? The hepatic arteries arise from the
antero-ventral part of the heart. The sternal artery
arises from the posterior end of the heart, ventral to the
superior abdominal artery. Notice that it divides soon
after leaving the heart. What direction do the branches
take? Sketch the circulatory system in in an outline.drawing
ef the animal: Killa specimen a: and take some” blood from
sie Soisaraial sinus and examine with the microscope.
Note its color and account for the same,

THE DIGESTIVE SYSTEM—Dissect away the gills
and other organs on one side to expose the stomach,
What ‘is its shape and position? Are there muscle fibers
extending from the stomach to any other part of the body?

' A MANUAL OF ZOOLOGY —- 23

iat is its relation to the mouth? Describe the oesopha-
s, leading from the mouth to the stomach. Note’ the
‘diac and the pyloric regions of the stomach. With
ssors remove the wall ‘of the stomach and note the
-d portions or ossicles. Do they have any definite ar-_
igement? How are they arranged? How many of them
> there? The gastric teeth will now be seen: a pair of
eral teeth, and a median tooth. Demonstrate the motion
these teeth. Is there any division between the two
tions of the stomach? ‘Trace the intestine from the
mach to the anus. Note an enlargement near the
sterior end, the coecum. Look for folds on the inside
the intestine. At the sides of the stomach will be found
obulated mass, the digestive glands. Try to find the
2t leading to the stomach.

The excretory system consists of the green glands or
Ineys in the lower side of the head. Trace the duct
m these glands to its opening at the base of the antenna.
iat name will be given to this duct?

THE REPRODUCTIVE SYSTEM—In the male the
ites will appear as tubular organs extending from the
eral angles of the stomach into the abdomen. In the
tyfish they differ in being bilobed anteriorly. If a live
acimen is at hand cut the testes and examine some
the fluid for sperm cells or spermatozoa.

Trace the tube (vas deferens) of the testes to its
sernal opening. In the female the ovaries compare in
ary respect with the testes of the male. Some may have
zs-in them. Trace the oviduct to its extérnal opening.

THE NERVOUS SYSTEM—To study this it will be
cessary to remove the muscles and viscera. Begin
th the abdominal ganglia and carefully trace the chain
yhalad through the thoracic ganglia to the sub-oesopha-
al ganglion, thence by a pair of nerves around the
sophagus to the supra-oesophageal ganglion, or brain.
‘tte the number of ganglia in each case and make drawing .
show the nervous system. A living specimen should
w be at hand. Place it in a jar of water. Note its
wements. Does it swim? Tabulate the different move-
mts observed. Place some meat or bread in the jar of
ter some distance from the specimen and cause currents

24 A MANUAL OF ZOOLOGY

of water to pass from it to the animal. Note any evidences
that the animal knows of the presence of food. Draw
a bristle over its back and note if one place is more Sehsi-
“tive than another. Pass your -hand quickly by the7jar.
Does it see? From the study so far what can be said of
this animal as to special senses? With a pipette place
some carmine ground fine in water, close to the thorax.
What becomes of it? This will demonstrate how the ani-
mal breathes.

il LOCUST.

EXTERNAL ANATOMY—Note the segmented struct-
ure. There are three main groups of segments: head,
thorax, and abdomen. How many segments appear in the
head, thorax, ahd in the abdomen? The thorax is dis-
tinguished by five pairs of appendages. What are they?
Note the three divisions of the thorax. Compare the
segments of the abdomen with those of the head, in
reference to shape, structure, and distinctness.

BODY WALL—Note the hard covering,the chitin.
The uneven distribution of the chitin produces the defi-
nite portions, the sclerites. Examine the stirtace of the
specimen with hand lens. As the head is pulled note
that the membrane that holds it in place has very little
chitin, if any. Note the narrow furrows that separate the
sclerites, the sutures, In many places the sutures are not
distinct and the sclerites are fused.

THE HEAD—Two divisions of the head are readily ‘
distinguished: the fixed portion, the cranium and the mov-
able portions, the appendages. The Fixed Parts of the Head:
two large rounded bodies, the compound eyes. They
occupy a large portion of the latero-dorsal portion of the
head. Study the compound eyes with the _ microscope.
Note the structure. Compare it with something you have

~ already studied. Make drawing to illustrate the structure ..
of one of these eyes. -Cephalad of the dorsal half of each
of the compound eyes find a small transparent body, the
simple eyes or ocelli. In a pit in center of cephalic sur-
face of head note a third simple eye. Note a large sclerite
surrounding the compound eyes, and bearing the simple
eyes, the epicranium. A suture extends ventrad from the

A MANUAL OF ZOOLOGY 25

eyes and separates the cephalic from the lateral parts of
the epicranium. The epicranium is limited ventrally by
a suture that connects the ends of the sutures just referred
to. Mount the head on a pin. A ridge marks the caudal
border of the epicranium. A well-marked suture forms
the ventral border of the lateral part of the epicranium.
Point out the vertex, the front, and the genae. A short
but broad sclerite, the clypius occupiés the ventral border
of the epicranium. Note a movable flap, the labrum, Make
a drawing of the cephalic aspect of the head. Note the ~
parts. Loéate the post-génae caudad of the genae on each

' side. Note that the post-genae are connected from side :
to side within the head by a strong membrane, the ten-
torium. Movable Parts of the Head: Antennae and the
mouth parts; just cephalad of each compound eye note
the attachment of the antennae. Each antenna is situated
in a depression which is known as the antennary fossa.

: Carefully remove the labrum. Now a pair of jaws,
the mandibles, are exposed, which open by meso-laterai mo-
tion of each jaw. Each jaw consists of a short and a
thick piece; the distal extremity of the latter is notched so
as to form a series of teeth. At the base of the mandible
between it and the gena, there is a small sclerite; this
is the trochantin of the mandible. By the removal of the
mandibles there is exposed a second pair of jaws, which
like the mandibles open by a meso-lateral motion. These
are the maxillae. Remove one of these and examine _
under the microscope. Make a cise goa tetial 1p
parts, which are as follows+—Gard inge is the proxi-
mal part of the maxilla. It consists of two sclerites; -the---
“frst is the larger and is triangular in outline, The stipes
or foot Stoic is the large quadrangular sélerite which forms
the central part of the maxilla. The lacinia articulating
to the distal part of the stipes, is a large sclerite which
tapers distad, is curved and is terminated with strong
teeth. Joined to the lateral border of the stipes and be-
tween the cardo and proximal segment of tle galea is a
narrow sclerite, the palpifer. Attached to the distal end
of the palpifer is a long slender organ consisting of five
segments: the maxillary palpus. Note the parts of the
thorax. The cephalic or first segment is named the pro-

.

26 A MANUAL OF ZOOLOGY .

thorax; the second or intermediate, the mesothorax; and
the third or caudal, the metathorax. These divisions
can be easily recognized by the appendages they bear. To
the first segment is attached the first pair of legs; to the
second is joined the second pair of legs and the first pair
of wings; and to the third or metathorax, the third pair
of legs and the second pair of wings. On the dorsal part
of the prothorax- note the sunbonnet shaped piece, the pro-
notum which covers the greater part of the sides as weil
as the dorsal ‘part of this segment. Make a drawing of.
the lateral asnect of the pronotum. ‘The two segments,
known as the metathorax and the mesothorax, are firmly
joined together forming a box to which two pairs of
Wings and the second and third pairs of legs are attached.
The dorsal part of the mesothorax is termed the meso-
notum, that of the metathorax the metanotum. Examine
the vetral aspect of the first pair of legs. Each leg will
be found to consist of the following parts: the proximal
segment, the coxa; the second segment, the trochanter.
This is smaller than the coxa, The third segment, the
femur, is the principle segment of the leg. The fourth
segment, the tibia, nearly equals the femur in length but
is more slender. The tarsus includes all that part distal
to the tibia. ‘On the ventral surface of the tarsus note
the series of cushions, the pulvilli, Make drawing of one
of the legs. Name the parts. Se

The long parchment like wings are found on the
mesothorax and are known as the mesothoracic wings.
The large fan-shaped wings, folded under the mesothoracic
wings are the metathoracic wings. and are the most im-
portant for locomotion. Compare the texture of these
two pairs of wings. Make a drawing to represent one- of
each pair,-- What seems to be the function Of the front
pair of wings?

Note the number of segments in the abdominal region.
Owing to the complexity of the caudal region, there is
a difference of opinion as to the number of segments,
but eight segments are readily distinguished in the female
and nine in the male. On each side on the dorso-lateral
region of the first segment find a large opening closed
by a very delicate membrane, The whole is the auditory or-

A MANUAL OF ZOOLOGY ; 27

gan and the membrane is-the tympanum. The next seven or
eight segments are very similar and without appendages.
Note the spiracle or breathing pore on each. Alsa note
the sterna and the pleura and how the two are united
by a thin membrane. In the female specimen note the
ovipositor consisting of four strong, curved, and pointed
pieces which form the most caudal part of fhe body. How,
and where does -the locust lay its eggs? What sugges-
tion do you get from the structure of the ovipositor?
The opening’ of the oviduct is between the ventral pieces.
Make drawings of the dorsal and the lateral aspect of this
_ part of the.bedy. In the drawing of the lateral aspect
represent the entire abdomen. Make drawings of the

dorsal and lateral aspect of the male als6-=—<————
PHYLUM MOLLUSCA

I. THE PELECYPODA
Unio, or Anodonta (Fresh Water Mussel.)

Study, the empty shell. What is its shape? Of how
many parts or valves does it consist? How are they held
‘together? How does the animal rest when alive? Point
out the dorsal, and the: ventral surfaces. Treat a small
piece of the shell with HCl. What is the result? Draw a
te ne What is the relative posi-
tion o e valves after the animal is taken out? Why?
How does the hinge act? Notice the lines of growth
beginning with the umbo or beak. Note the hinge teeth
(not present in anedonta). How do they fit when the
shell is closed? How many forms are there? Does the
color of the valve vary tinside? Note the palial impres-
sions, (the line of attachments ofthe mantle to the shell.)
Note the scars for the attachment of the muscles. Hx-
amine the broken surface of a shell with a hand lens.
What attachments does the body have to the shell? Study
the texture of the mantle. Is it uniform in thickness?
The adductor muscles hold the valves together. How
many are there? How do they differ in size, and in shapé?
The scar for the retractor pedis muscle is at the upper
margin of that of the adductor muscles. A little below

‘ the anterior retractor muscle scar will be found the scar

28 A MANUAL OF ZOOLOGY

of the protractor pedis muscle. In marine forms the
scars are not all distinct. ’

Note ,the siphons. How many are there? What is
their shape, and size? Are they separate tubes? ‘urn
back one of the lobes of the mantle and note the palial
cavity. The large ventral cavity is the branchial cavity,
and the small dorsal cavity is the cloacal cavity. What
is the relation of the abdomen to the muscles and to the
foot? Compare the texture of the foot with that of the
abdomen. What direction does the foot take when ex-
tended? Note the gills, or gill-plates. How many are there?
The supra-branchial chamber is laid open when a slit is
made along the attachment of the outer gill and the man-
tle. Demonstrate the following in the structure of a gill:
the water tubes, the inter-lamellar junctions, and the
inhalent apertures. Sections will be needed. Study the
ciliary action on the gill split open. Make a drawing
to show-the structure of the gill.”

Find the mouth and note its size, shape, and position.
How do the labial palpi compare with those-on the lobster?
Into which siphon does the anus open? It will require
care and patience to work out the digestive system. From
the mouth trace, the oesophagus. What is its direction?
The liver will appear as a dark colored mass around the
stomach and the oesophagus. How is the stomach dis-

- tinguished from the oesophagus? The bile duct opens into
the oesophagus near the stomach. Trace the intestine
from the stomach through the yellowish white generative
gland. Note that the rectum passes through the pericardial
cavity. Note the typhlosole, a prominent ridge on the’
ventral ‘side of the rectum. Where has this organ been
seen on previous specimens? Make an outline drawing
of the body and place a , diagram of the digestive system
in the-same, -—- mare

THE CIRCULATORY SYSTEM—Carefully remove a
living specimen from the shell. The movements of the
heart may be observed. Open the pericardium and study

‘the heart. Note the median ventricle and the two lateral
fan-shaped auricles: The intestine was traced through
the ventricle in the other specimen. Trace the anterior
dnd the posterior aorta, the former above, and the latter

‘

A MANUAL OF ZOOLOGY 29

below the intestine. Compare the auricles and the ven-
tricle as to structure. :

THE NERVOUS SYSTEM—Preserved specimens are
to be used here, Separate the palpi and find the cerebral
ganglia just under the skin. Nerves may be traced to the
adductor muscle and to the pedal ganglia in the foot.
Separate the gills at the posterior end of the body and
find the visceral ganglia.

THE EXCRETORY SYSTHM—Find the kidney as a
dark colored tube with spongy walls under the pericard-
ium. ‘The renal aperture will be seen as a small pore at
the anterior end of the pericardium. Find the genital
aperture near the renal aperture. Study live specimens
in an aquarium containing three or four inches of sand.
There will thus be several interesting observations made
on the habits of the animal. Specimens will be preserved
in chromic acid and cross sections made for gross struc-
ture. ra

Il, CEPHALOPODA
Loligo Pealii (Squid.)

The habitat of the squid usually corresponds with that
of the larger number of salt water fishes. This is because
he can thereby obtain his food to a better advantage.
Fishermen often get large quantities of squid in their
‘nets, and from them squid may be obtained during certain
seasons of the year at a small cash outlay or by a little
‘trouble.

For dissection squid should be preserved in formalin
or alcohol, preferably the former. The can containing
them should contain formalin 4 per cent, also some iron
filings or old nails. Specimens thus preserved show good

hardening and also the denser parts are colored a little
. darker‘ than the others, ‘thereby givirig a better definition.

EXTERNAL FORM—What is the general form of the
pody? What is the shape of the animal as to anterior and
posterior ends? Is the head movable? Notice the mouth
in the space between the arms. How many arms are
there? In some specimens a peculiar formation is seen
projecting from the mouth, What is this?

Notice the eyes. Note their size. Compare them with
those of the lobster-or locust.

30 A MANUAL OF ZOOLOGY

A crenated fold of membrane will be found just
behind the eyes, the olfactory organ.’ What is its extent?

Notice the large triangular fin on the end of the body
farthest from the head. Consider its use.

SURFACE—Dark brown pigment spots, chromato
phores, will be found on the surface. These vary in shape,
and number. Observe, with the hand lens, that some of
.these have blurred edges and others are clear cut. The
chromatophores are very changeable during life. When
the animal was killed the chromatophores were caught in
the condition and shape in which they were at the time.
The changes are interesting to observe for the chromato-
phores gradually fade in color and reappear so evenly that
they present a blush of color gradually from one point
to another over the entire surface. At times the color
almost disappears and the animal is nearly invisible in
the water.

PLACE .IN ANIMAL KINGDOM—Does the external ap-
pearance suggest that this animal should belong in the
same class as the clam? Explain.

Taking the DORSAL view of the head, is the animal
bilaterally symmetrical? If so how many arms are found
on each side? Are all the arms the same length? How
many rows of suckers are found on the short arms? On
the long arms? Dray the e dorsal view.

Ventral View—What is the direction of the muscular
bands that extend from the body to the fins? Notice the
projections of the anterior edge of the mantle. Find the
siphon projecting from under the mantle in the mid-
ventral line. What is its shape, size, and the direction
‘of its opening? Discuss the siphon as an organ of motion,

Examine one of the grasping arms (long arms). Ex
‘amine closely one of the suckers on this arm. Does it
have a stalk or is it sessile? Is there anything peculiar
about the margin of the suckers or acetabula? Cut through
the sucker and piston longitudinally. Mate carefully and
make drawin; e section, cs

INTERNAL ST URE—Is the mantle fastened to
the head in any way? If so at:-how many points? Notice
mantle cartilage on the dorsal surface of the heck. What
is its shape and extent? Are ‘there any projections from

A MANUAL OF ZOOLOGY 31.

the margin of the mantle ventrally? Are there any indi-
cations of cartilage on the siphon? If so what is its use?
Open the animal along the mid-ventral line. The two
sexes differ in that the nidamental glands of the female,
cover the other organs and give the appearance of a

thick, granular substance. Notice four large muscles that -

attach the head to the mantle; two dorsal retractors of
the head and two ventral retractors of the siphon. A
pair of silvery cords will be seen extending from the neck,
just posterior to the dorsal mantle cartilage, to the mantle.
These are nerves which terminate in large ganglia on the
inner surface of the mantle.

Are there any cartilage formations on the siphon? If
so is there anything on the mantle corresponding to the
same? ; :

Note the two valve-like sacs lateral to the siphon
sac which is on the mid-ventral line. Does their shape
and position suggest their use?

Find the rectum and the anal opening directly posterior '

to the siphon. Is there a mesenteric fold to keep the
viscera in place? Wook for the ink sac immediately dorsal
to the intestine. Find the duct and opening from this, sac.

At the end of an elongated papilla which lies parallel
to the intestine, and on the right side will be found ,the
opening of the male reproductive system. Find a pair of
papillae, about an inch from the anal opening, which are
openings for the renal organs. Trace the ducts, if possible,
posteriorly to the renal organs.

Look for the gills’on either side of the mantle cavity.
How many are,there? How are they located as to the
retractors of the.siphon? Notice a. vein running from
the renal organ to the gill, (branchial vein). Find the
branchial heart, a small, oval, white body at the base of
each gill.

From a point midway between the branchial hearts
notice a narrow membranelike cord coming off and pass-
ing across the mantle cavity to the mantle. - Does it have
any braziches after it reaches the mantle? This supplies
the mantle with blood and is called the median mantle
artery. Find the lateral’ mantle arteries. Posterior to
these arteries find a large sac reaching to the posterior

32 A MANUAL OF ZOOLOGY

end-of the body. Make a drawing of the specimen_as_it..
now stands. Se ee ts

BEES A pair of white granular bodies will be seen on either
side of the intestine and extending posteriorly to about
the region of the heart, renal or nephridial organs. Pick
these away carefully after severing the mesentery, and
the heart will be plainly brought to view. As the renal
organs are taken out the intestine may be followed
between the two cavities.

The venae cavae are thin,~transparent vessels. The
anterior cava runs back as far as the branchial heart and
there unites with the. posterior cava which at this point
becomes nearly as broad as long. Sometimes these vessels
contain blood so they may be easily traced in preserved
Specimens. Upon dissecting the posterior vena cava
away the dorsal mantle artery is seen, Notice the bran-
chial hearts are in separate pericardial chambers. Turn
these hearts over. How many vessels open into them,
and how many out of them? The blood is collected in the
branchial hearts from the vena cava and forced to the
gills, there collected again and brought to the systemic
heart.

Lay the anterior end of the intestine back and find a
. Pouch: -sHaped sac below the ink bag, the spleen. This
recéives a branch from the anterior vena cava. :

THE SYSTEMIC HEART AND ARTERIES—What

. is the shape of the heart? How situated? Size?_ Is it
placed directly on the median line? Is it placed with
about equal portions on either side of the median line?
How many vessels Jead to or from the heart? Find. the
anterior, ,and the posterior aorta. Also the right and the
- left branchial veins. Trace tne posterior aorta and notice
the branches, The anterior aorta may be traced later, to .
the head. Make a drawing of the circulatory system,

THE DIGESTIVE } SYSTEM—cut away the systemic
heart with its. arteries also the, blind sac (a transparent
membrane which contains the stomach.) x

The stomach is a large muscular bag. Trace from
the anterior: end the intestine and the oesophagus side by
side. Notice that the intestine takes a turn at this. point.
and terminates in the rectum. Trace. the oesophagus until

= A MANUAL. OF ZOOLOGY 33

it entedigre liver. A delicate duct will be found jeading
fromthe liver to the spleen and on to the stomach, on
eith de of the oesophagus as it enters the liver, hepatic
duc esortns the liver as to location, size, shape, and
color: Now trace the aorta and the oesophagus through
t er and from there to ‘the head. Watch for the sali-
vary glands on the dorsal’ surface mE the anterior end of-
the liver. Make a drawing of

REPRO ORGANS-—The testis or ovary ac-
cording to sex, is a ‘white dense mass under the stomach
on the median line and ‘extends posteriorly. Notice the
accessory reproductive organ at the left. Notice on the
left ventral arm of the male that ‘the acetabula are modi-
fied so ‘that the ‘stalks are prolonged into blunt boints.
Compare these with those of the female. :

No duct joins the testis with’ ‘the vas deferens. There-
fore the ripe spermatozoa pass through the cavity al the
capsules into the excretory duct. : "

The ‘reproductive organs of the female comprise ‘the
ovary, oviduct, gland of the oviduct, nidamental glands,
and accessory ‘nidamental glands.’

Find the nidamental glands, upon opening the mantle,
cavity, in ‘the region of the’ heart, as white laminated
bodies. ‘The’ capsules of the ege masses are excreted by
these. The accessory glands are found in the ‘region ‘ of
the ink sac. —

‘Look for the ovary in similar position as “the ‘testis

of the male. ‘The eggs” escape from the ‘capsule to ‘pe
taken up by the oviduct. The oviduct, a long: thick-walled
tube, passes along the left side and opens. in the” ‘region
of the siphon. —
"The oviduct may be traced to a point | below the lett
gill into the large oviducal gland, at’ the left of the ‘poster-
ior end of the nidamental gland.’ Look ‘for eggs in varying
stages . of development. in the OVER;

Carefully take away all the ‘organs ‘of. the body cavity,
turn the animal upon the ventral. ‘side, and cut, through
the integument along the mid- dorsal line. . An elongated
cartilaginous pen will be found here, Take i
and make_a drawing of it describi words aswell:
Does this pen suggest in any way, a shell?” Is the pen

34 A MANUAL OF ZOOLOGY

fastened in any way to the walls of the cavity? If possible
find some communication of this cavity either with-the
interior or exterior of the body.

Divide the head vertically along the median line and
find the following: the opening of the mouth, the horned
beak, one part shutting under a larger, Which is dorsal?
Which is ventral?

Notice the somewhat spherical buccal body. Of what
is it composed? What is its use? Find the oesophagus
running back through the buccal body. Find the lingual
ribbon. Follow the oesophagus posteriorly through the
head to the body. Which side of the liver does it pass?

Around the oesophagus posterior to the head, notice
the cartilaginous cranium. What does this cranium con-
tain? Are there any ganglia elsewhere around the oesoph-
agus? Find the stellate ganglia referred to before. Trace
the radiating nerves to the differnt parts of the mantle.
The anterior branches may be traced through the retrac-
tors to the infra-oesophageal ganglion.

Find the large optic ganglia by removing the ventral
side of the head. Look for the auditory chambers as the
cartilage is cut away. The pedal, the pleural, and the
visceral ganglia are fused and lie ventrally, between the
optic ganglia. They together make up the infra-oesoph-
ageal mass. This mass is prolongated anteriorly into the
pro-pedal ganglia, from these ten nerves pass to the arms.
From the lower position of the infra-oesophageal mass
the siphon nerves are given off. The pleural and the
visceral nerves pass off further back.

Make a drawing of the free surface of a .vértical
section” putting in alt the -mouth parts, the oesophagus;
and the oesophagael nérvé mass, jac, Co

The study of microscopic’ ‘mounts thnoien the anterior
part of the body will give better results than can be had
by the dissection of a larger specimen, ‘especially for the
nervous system. Notice. the following points under the
microscope, they being the most important. -The series
of slides should be taken in order from sis Sutenion toward
the posterior. part of the head.-

- 1. Cut surface of five pairs of arms.

» 2 Nerve ganglia near center of each arm.

A MANUAL OF ZOOLOGY 35

3. In center of section a large oval body, the buccal
mass.

4. The mouth on the ventral surface,

5. Small. dorsal beak, dorsal to the mouth.

6. The large mandible and the muscle which moves it.

In section through the eyes:

1. The small oesophagus near the center of the section.

2. Pedal ganglia on the middle line of the body.

3. Hyes on the side of the head.

4. Anterior chamber of the eyes. The posterior cham-
ber. The line between the two. :

5. The cornea. The central opening, the pupil.

The posterior chamber is filled in the living animal
with vitreous humor.

6. The retina on the back of the eye; examined under
high power, rods between the lines of pigment will be
found.

%. Layer of cartilage outside of the retina.

8. Optic ganglion outside of the cartilage.

Section posterior to the eyes:

j. Cerebral ganglia dorsal to the middle line.

2. Optic ganglia on éach ‘side of the head.

3. Pedal ganglion on the ventral surface of oesopha-
gus

4. Head cartilage outside. of the brain.

‘5. Upper end of siphon ventral to the head.

Study a section through the base of the head.

Make a drawing. of each section, pitied at Boone.

iving animal is a very interesting one to study.
His motions are quick. He moves in any direction by
means of the fin and the siphon. His movements back-
ward are exceedingly swift, being brought about by the
action of the water as it is thrown out of the siphon. The
blind sacs, spoken of above, act as valves that allow the
water to enter the mantle cavity, but as the’ mantle con-
tracts to send the water out they close and the water is
forced out through the siphon in ‘jets. “He has the power
to vary'the direction of the jet by’ mpenne = os of the
siphon ‘to ‘various positions: ©

- His color is constantly changing as* explained above.

“Phe tentacles. are‘in: constant motion, in search of food:

36 A MANUAL OF ZOOLOGY

Upon being irritated he quickly projects black ink,
which is secreted in the ink sac, through the siphon and
he is suddenly enveloped ina cloud of black ‘fluid which
affords him an easy means of escape from his enemy.

His large eyes, his great variety ‘of motions of tenta-
cles and body, and his change of color, give him on the
mnie a | very_odd- appearance,

. PHYLUM CHORDATA

ELASMOBRANCHII

The Dog-fish (Mustelus canis)

EXTERNAL FORM—What is the general form? ‘Does

it belong to. the fishes? Why? (See Herwig, page 557).
Can you ‘determine ‘divisions: ‘head, ‘pody,’ and tail?
Note the rostrum or beak, anterior to the ‘mouth
and eyes. Note the position and shape of the eyes.
Are there eyelids? With the teniaculum hook up the
membranous fold undér the eyé, and draw it up over the
eye. This is the nictitatiig membrane.’ Has it ah ana-
logue among the higher types? Immediately’ posterior
to the eye note a small opening, ‘the 'spiracle. | Posterior
and somewhat ventral to the sjiracle you will‘ see five
slits which are the gill clefts. Is there an arrangement by
which they may be’ closéd? Lift ‘up the flap of skin cover-
ing them and notice the gills or branchial apparatus. Can
you demonstrate the connection of the zill-clefts and the
spiracles with ‘the ‘pharynx, and ‘niowth? What would you
infer as to the functidn’of the spiracles from ‘the deriva-
tion of the word? What reasons would you give that
water goes from thé mouth through ‘the ‘spiracles and the
gill-clefts instead of in the opposite: direction?” On the
ventral side of the head, some distance from the front
of the beak, note the triangular-shaped mouth. Are the
teeth placed in rows? Look at them with the hand lens,
How would the fish seize food thrown upon the surface
of the water aliove it? Open thé mouth and examitie the
tongue. Is there any connection between the size, length,
and shape, and the absence of molar teeth as found in the
higher forms? Can you assign any reason for ‘the flat
surface of the underside of the head and: the rostrum?

.

A MANUAL OF ZOOLOGY 37

How many paired fins has the fish? How many unpaired?
Have the paired fins any relation to the limbs in the higher
forms? By working the- anterior pair of paired fins, see
if you can determine something of the mode of connection
with the body. By pressing on the skin ventrally and dor-
sally see if you can determine the presence of the
pectoral arch. In the same way try to determine the pelvic
arch in connection with the hind pair of ventral fins. n-
mediately posterior to this latter pair in the angle formed
by their approach to the body the anal or cloacal opening
is found. If the fish is a male you will observe that the
inner part of each of these fins is specialized to form a
pair of séxual organs. Note the opening of the sperm duct,
‘Where is it found? The cloacal or tail fin is heterocercal.
(See Kingsley, page 229). On each side of the fish ex-
tending from near the spiracle_to the tail note the lateral
line. (See Weidersheim and Parker, page 191 and Weysse,
page 275). By. pressing on the. skin of the fish taken
from the preserving fluid one may demonstrate the pores
of the skin. They are especially’ noticeable on the. head
near the spiracles. Examine the skin with the hand lens.
It seems to be covered with fine teeth. Which direction
do they slant? Look up the word “shagreen”. These
scales are of the placoid form. “(See Kingsley, page 228).
Make a drawing of the external appearance. Make a draw-
_ing of the musculature on the side after the skin has been
removed.

DIGESTIVE SYSTEM—Open the abdominal and the
thoracic cavities by a median cut extending from a short
distance in front of the anal opening to a point opposite
the posterior corner of the mouth. The body is lined with
a silvery membrane, the peritoneum. In the abdominal
cavity note the large bi-lobed liver. Between the lobes
of the liver note the stomach connected by a short gullet
or oesophagus to the back part of buccal cavity or pharynx,
By pushing a scalpel handle or other blunt instrument
down the oesophagus demonstrate the connection with
the stomach. The stomach is V-shaped, the large anterior
end being known as the cardiac and the posterior end as
the pyloric stomach. Attached to the posterior end of the
cardiac stomach and extending around the angle of the V

38 ‘A MANUAL. OF. ZOOLOGY

and along the entire length of -the pyloric stomach is a
large, reddish organ, the spleen. Is it continuous? Pos-
terior to the opening of: the stomach into the intestine,
lies a small, flattish, irregular body, the pancreas. Demon-
strate. Is there a small intestine? Open the stomach
along its’ ventral edge until you demonstrate the pyloric
opening. Note the contents of the stomach. Wash the
stomach clean and examine its mucous lining carefully
with the hand lens for the openings of the stomach glands.
Note differences in the lining of the stomach in the differ-
ent parts. Open the intestine and note the peculiar mem-
branous folds in the interior of the posterior portion, the
spiral valve. Is the name justified? What might have
been its origin? What the use now? Extending from the
dorsal wall of the intestine near the posterior end notice
a small diverticulum-like gland, the anal gland. The in-
testine opens into a short chamber common to it as well
as to the ureters. This is the cloaca. Make a drawing
of the digestive apparatus. Show the spiral valve in a
separate drawing.

CIRCULATORY AND RESPIRATORY SYSTEMS—
The heart lies in the pericardial cavity in the mid-ventral
line, just under the pectoral girdle. The posterior wall of
the pericardial cavity has the appearance of a diaphragm.
The heavy, thick-walled middle portion of the heart is
the ventricle. Anterior and connected to this note the
conus arteriosus, which is developed from the ventricle
as is indicated from the striped muscle fibers of. which
it is composed. Posterior and dorsal to the ventricle lies
the thin-walled atrium or auricle. Posterior and dorsal
to this lies the sinus venosus, which is developed as a
part of the vein ending, and has the appearance of a thin
membrane. This is determined by the smooth muscle
fibers of which it is composed. From the anterior part of
the conus arteriosus trace forward the ventral aorta. This
gives off an afferent branchial artery to each gill-pouch.
They enter the gills from the ventral side. Demonstrate
each one by the proper longitudinal cuts at the ventral
ends of the gill-clefts. Carefully dissect off the skin from
the roof of the mouth and expose the efferent branchial
arteries, then trace them until they converge to form the

A MANUAL OF ZOOLOGY. , 39

dorsal .aorta. The one arising from the posterior gill-
cleft unites with the one in front of it. Open the spiracle
and see if you can demonstrate that it is a rudimentary
gill-cleft. From the first or anterior pair of efferent bran-
chial arteries trace forward the two common carotid arter-
jes, _ Note that each one of these divides into two
branches; an external which goes to the eye and surround-
ing region, an internal which, approaching its mate from’
the opposite side, pierces through on the median line and
supplies the brain. Trace the dorsal aorta posteriorly.
Note and trace the first branches, the two subclavian. ar-
teries to the pectoral fins. Posterior to the subclavian
arteries the first median or coeliac axis is given off,

Trace this through its first branch, the anterior gas-
tric, to the front part of the stomach, and through its
second branch, the hepatic, to the liver. The second
median artery, the anterior mesenteric sénds a branch,
the lineo-gastric, to. the posterior part of the stomach and
another to the spleen. Demonstrate this. The third
median artery, tha posterior mesenteric, supplies the rec-
tum and the rectal glands. Trace these points out. The
dorsal aorta also gives branches to “the genital organs,
the kidneys, and the pelvic fins. It continues into the
tail as the caudal artery.

The venous system can be traced from the sinus
venosus by three veins which lead into it. A pair of
smaller ones, the hepatic veins, come from the liver. . The
larger, a short trunk directed anteriorly and ventrally,
the pectoral sinus or ductus Cuvieri, receives the subcla-
vian veins. The ductus Cuvieri is formed by a pair of
jugular or anterior cardinal veins returning the blood from
the head region, and a pair of posterior cardinals bringing
the blood from the posterior regions. Each anterior cardinal
has an expansion, the orbital sinus, which surrounds the
eye. The veins entering the kidneys from the tail are
often called caudal veins, but may be considered as the
posterior cardinals which, after performing the portal cir-
culation of the kidneys, collect and empty into the ductus
Cuvieri. The hepatic portal vein is formed by the junction
of veins from the intestines, pancreas, and the spleen.
The lateral vein brings blood from the femoral ‘and some

40 A MANUAL OF ZOOLOGY

of the cloacal veins to the ductus Cuvieri. It runs parallel
but ventral to the dorsal aorta. Open the heart through
all of the chambers by a ventral cut. Demonstrate the
valve between the ventricle and the auricle. Demonstrate
the pocket valves in the conus arteriosus. How many
transverse rows of valves and how many valves in each
row in your specimen? Open the nasal cavity. Where
does it open posteriorly? Note carefully the lining of the
nasal cavity. Make a drawing of the circulatory system.
Expose the internal gills‘and make a diagram showing the
circulation in the gills.

THE EXCRETORY AND THE GENERATIVE SYS-
TEMS—The kidneys lie in the posterior part of the body
cavity on each side of the spinal column and may be ex-
posed by carefully cutting away the peritoneum covering
them. They are long, flattish, lobulated organs composed
of bunches or lobes of tubules. The tubules forming the
hinder portion of the kidneys are called the metanephros
or trué kidneys. The tubules from these lobes unite to
form about six branches. These join one another to form
a duct, the ureter, which opens directly into the cloaca
in the female and in the male into the paired uro-genital
sinus which empties into the cloaca. Demonstrate. The’
anterior part of the lobulated mass is known as the meso-
nephros. This is rudimentary in the female. In the male
the tubules serve to carry the spermatozoa. Find in the
male, in the dorsal part of the dorsal cavity, two long
flattish bodies united with one another posteriorly. They
are the testes and are connected anteriorly by slender
tubes, the vas deferens which leads to the cloaca. Dem-
onstrate. The posterior end of the vas deferens is dilated
forming the vasicula seminalis. In the female look for
the single ovary in the dorsal part of the body cavity
suspended in folds of the peritoneum. Back of the vis-
cera, extending from a position near the posterior end of
the heart to the cloaca, are the two oviducts united in
front and opening by a single large aperture into the
body cavity. Notice an enlargement of each duct, the shell
gland. How do the ova get into the oviducts? Draw the-
uro-genital apparatus.

A MANUAL OF ZOOLOGY 41

THE NERVOUS SYSTEM AND THE ORGANS OF
SPECIAL SENSE—The central nervous system consists
of the brain and the spinal cord. Open the dorsal part
of the skull, cutting and picking away the cartilage of
which it is composed with the scissors and forceps until
the brain is entirely uncased. This will necessitate care-
ful work, especially where the olfactory lobes are continued
forward; the pituitary body downward, and the pineal body
upward. Cut the cranial nerves as far from their attach-
ment as possible. Are there sutures in the skull? When
you are picking away the skull investigate the structure,
first of the nostrils. Where do they open posteriorly?
Are they functional as organs of smell? . Second, the
structure of the eye. Note the muscles. How many pairs
are there? Are they fastened to the thick outer coat or
sclerotic? In what direction does each move the -eye?
Take the eye from the socket cutting the optic nerve
-close to the eye ball. Open the eye. What is the com-
parative shape of the lens? Is it different from the shape
of the lens in the higher ‘forms? What is your conclusion
from the shape as to the range of vision? Divide the two
lenses. What is the comparative size of the space filled
with the vitreous humor? .Note the black inner coat, the
choroid, and interior to this the retina. Does the optic
nerve enter the posterior part of the eye? Posterior to
the eye carefully dissect out the mucous ‘sae constituting
the ear. Does -it have a connection with the pharynx?
With the external surface? With the brain? Find the
ossicles. Test with HCl. What is their composition? Use?
Trace the auditory nerve. What are the essential condi-
tions of hearing? Does it function as an organ of hearing?
What other function beside hearing has the ear in the
higher forms?. Work out the muscles, using the frog for
comparison. -

Find the olfactory: lobes as the foremost part of jhe
brain. Note the connection with the sensory metnbrase
of the nostrils. The short stem connecting these with the
body of the brain is the olfactory tract. It is connected
with the prosencephalon, a part of the fore-brain. On the
dorsal side, back of the fore-brain, constituting a paft of
the ‘twixtbrain, note an upward and forward tube-like

42 A. MANUAL OF ZOOLOGY

projection, the epiphysis. or pineal gland: (On the function
of this gland see Weidersheim and Parker, page 155).
Anterior to the base of this.tube remove a little of the
membrane and find the third ventricle. The posterior
part of the fore-brain is called the thalamencephalon. On
the ventral side of the brain back of the thalamencephalon
find the optic nerves. On the dorsal and the lateral side
of the brain back of the diencephalon or the mid-brain
are the two optic lobes. Partly overlapping the optic
lobes and extending backward is the cerebellum which
constitutes the anterior part of the hind-brain. The taper-
ing part of the brain back of the cerebellum is the medul-
la oblongata. The cavity in the dorsal part of this is
the fourth ventricle. Running forward from this demon-
strate the narrow passage, the iter or aqueduct of Sylvius.
From the third ventricle demonstrate the passages into
the lateral ventricles and into the olfactory lobes. The
side walls of the third ventricles are the optic thalmi.
On the ventral side of the brain posterior to the optic
nerves note the hollow outgrowth from the floor of the
third ventricle. This is the infundibulum on the end of
which is situated the hypophysis or pituitary body. Note
the cranial nerves coming from the medulla. Make a
drawing of the dorsal and the ventral views of the brain.
Open the vertebral column carefully and expose the spinal
cord. Note how the nerves are given off. Demonstrate
the posterigr and the anterior nerve roots. Dissect out a
vertebra. Notice particularly the character of the articu-
lating facets. Dissect out the pectoral arch and note the
character of the articulating facets between the arch and

the fins.
‘TELEOSTOMI.

Teleost (perch).

NOTE—In working out this animal keep constantly
in mind the corresponding parts in the dog-fish and com-
pare them point for point.

EXTERNAL FEATURES—How does the general form
compare with that of the dog-fish? Is it bilaterally sym-
metrical? What are itsdimensions? (Length of fish is
measured from tip of snout to base of tail fin. Length
of head from tip of snout to the posterior edge of oper-

A MANUAL OF ZOOLOGY 43

‘culum). Can you distinguish ‘the. divisions, head, -‘body,
and tail? How?- What are cervical vertebrae? Would
you expect to find them in a fish? Do you find a lateral
line? Note the position of the mouth. Open it and find the
teeth on the upper jaw: They are on the premaxillary
bone. How is it fastened to the skull bones? The paddle-
shaped bone back of it is the maxillary. ‘Those consti-
tuting the sides of the lower jaw are the dentary bones.
Do they bear teeth? In the front of the roof of the mouth
is situated the patch of vomerine teeth, so called from
the bone upon which they are placed. Extending back
from these teeth on each side of the roof of the mouth
are two rows of teeth situated on the palatine bones. Are
the teeth placed in regular rows? Look at them with the
lens. What is their shape, their slant, and their function?
Back of the premaxillary bone nete a pocket-like flap or
valve with the opening turned backward. What is its
use? Is there a tongue? ,

Examine the position and general appearance of the
eyes. From a superficial examination of the eyes in how
many respects do they differ from the eyes of the dog-fish?
Do you think that the nictitating membrane in the dog-fish
-is an organ in the process of evolution or of degeneration?
Why? Press on the roof of the mouth and note effect on
the eyes. Was this effect possible in the dog-fish? An-
terior to the eye is situated a thin triangular bone, the
ante-orbital bone. Note a pair of openings in front of each
eye, the nostrils. Do they open into the mouth? Do they
communicate. with each other? Are there any valves for
closing them? Compare their situation, ‘with reference
to the mouth, to those of the dog-fish. Can you find a
spiracle? How many external gill: openings are there?
Find the operculum or gill covering and note that it is
composed of over-lapping parts the posterior of which is
called the opercle. Over-lapping the opercle in front is
the pre-opercle, This generally has a serrated hinder edge.
The inter-opercle lies within its dorsal edge under the oper-
cle and the pre-opercle and over the sub-opercle, which
is ventral. Considering the fact that there are a number
of gill-clefts in the embryo of this fish, what do the parts
of the operculum mean? Is the arrangement a better pro-

44 A MANUAL OF ZOOLOGY

tection to the gills than the dog-fish has? Make a draw-
ing illustrating the parts of the operculum. Raise the
operculum and examine the gills. There is a double row
of gills on the posterior edge of each, gill arch and a single
row of gill rakers on the anterior edge. How mtany gill
arches and gill-clefts are there? Depress the tongue with
the fingers and note the effect on the gills. What is the
meaning? On the inside of the operculum find a fleshy
projection, the false gill. Dorsal to the attachment of the
pectoral fin, note a sort of rudimentary operculum.

+ How many paired. and unpaired fins has this fish?
Are the paired fins much developdd? Notice the differ-
ence in the character and ‘the placing of the pelvic fins
as compared with those of the dog-fish. Make the same
observations with regard to the other paired fins. From
these observations do you think that. this fish should be
placed higher or lower in the animal scale than the dog-
fish? Are there modifications of the fins by which the sex
may be known?. In this regard which seems to be higher
or lower in the scale? Determine something of the ‘man-
ner of the articulation of the paired fins by working them.
Can you detect the presence or absence of pectoral and
pelvic arches? Note the difference between the. dorsal
and the pectoral fin rays. The tail ds homocercal. What
does that mean? : : :

Are .the scales imbricatéd or. are they tessellated?
Raise a scale carefully and note the thin epithelial mem-
brane reflected from its hinder portion to the scale under-
neath. Note the pigment granules in this membrane. Re-
move a-patch of scales and examine the fiesh underneath
to determine the method of attachment.. Examine a num-
ber of scales under the hand lens. Make an enlarged
drawing of a typical scale, showing the shape and mark-
ings. Imbricated scales are either. cycloid or ctenoid;
ctenoid if the hinder edge is toothed or spiny. Do the
scales covering the lateral line differ from those found
elsewhere on the body? How?

In front of the ventral anal fin demonstrate the open-
ing of the urinary and the reproductive organs. Do they
gpen together?: Locate the anus. Is this arrangement
typical of the higher or of the lower forms? Do you find

A MANUAL .OF ZOOLOGY 45

skin pores about the head of this fish? Make a drawing
of ‘the lateral surface of this animal. locating the different
external features. ot

THE VISCERA—Cut..away carefully one side of the
bedy wall from a short distance in front of the anal open-
ing -to the pectoral-fins and from the ventral ling as far
dorsally as-you -can without injuring the viscera ey
the air bladder. *“Note.the peritoneum.

In the fore part of the body -cavity lying aan in
the left side is the liver. -How many lobes has it? Is it
larger in size compared to the bulk of the ‘body: than ‘it
is-in the dog-fish? Demonstrate the’gall bladder and the
hepatic veins passing forward from the liver..: Demonstrate
‘the oescphagus and the stomach’ by: passing a probe down
the throat. Froni the anterior part of the stomach find ‘the
opening of the intestine. This form of stomach is called
eoecal. ‘About:a half inch from the anterior end of, the
intestine find projections from it,‘the: pytoric:coeca. How
many of these are there? Cut off the end of one of the
coeca. Where does it lead? What is its use?) Is the
intestine convoluted? ‘Trace it to the anal-:epening. If the
stomach of the dog-fish is of -the more ‘primitive type
from which the Teleostian type is‘a development, how may
the opening of‘ the intestizie from the anterior end be ac-
counted for? Do you find a‘panctreas? (See Shipley and Mc-
‘Bride, page 381). Observe that the viscera are held in place
_by ‘a thin membrane,! the mesentery. Notice how the
blood vessels are contained in it. Find a reddish body
near the intestine. This: is the ‘spleen.: Dorsal to the
intestine in the female finda long granular yellowish body,
the’ 6vary: ‘This may be very large at certain times of
the year, when the eggs are ripe. Trace the oviduct.
Does‘ it open into a cloaca? ‘Does this reproductive appa-
‘yatus indicate an advance in’the scale above the dog-fish?
Why? If the fish is a male notice the two white bodies,
the testes. Trace ‘the vas deferens. Find a urinary bladder
posterior: to the reproductivé organs. Where is its external
opening? “In the dorsal part of the’ body cavity find the
“air bladder. What‘is its use? Trace carefully its anterior
end to see if’it has a’ communication with the alimentary
eanal. Onen the oesophagus. stomach. and the intestines,

46 A MANUAL OF ZOOLOGY

and note the differences in the character of: the mucous
membrane lining them. Find the pyloric valve. Do the
pyloric coeca open into the intestines? In front of the
liver find a false diaphragm. Remove this and observe the
heart. The part most ventral and posterior is the ventri-
cle. The part above the ventricle is the auricle. Dorsal
to the aorta is a large thin-walled sinus venosus. Anter-
ior to the ventricle find the bulbus arteriosus. Is this
composed of different material from the ventricle? Trace
the ventral aorta leading from this forward until it divides
into two branches one going to each branchial apparatus.
Observe along the dorsal part of the body cavity under
the peritoneum, the dorsal aorta. How many branches
does it give off to the viscera? Can you find the long
kidney on each side of the spinal column? Where do the
ureters leading from them go?

Separate the lower jaws by a cut along’ the medial
line. Turn the sides back and notice how the gill rakers
fit into each other. Is the anterior row of gill rakers
different from the others? How? Observe where the gill
arches meet dorsally a large flat prominence constituting
the dorsal part of the pharynx. This is covered ‘with
numerous fine teeth. Opposing these on the ventral side
is a smaller patch of teeth. These are called the superior
and the inferior pharyngeal teeth. Do the gill arches have
joints? The bones supporting these are the pharyngeal
bones. Carefully pick away the flesh from’ the inside of
the pectoral and the pelvic arches’so as to expose the
bones constituting these arches. The largest bone of the
pectoral arch is the clavicle. It projects a little above the
base of the pectoral fin. Above this is the supra-clavicle.
The post-temporal! connects this latter with the’skull. The
bones connected with the ventral fins' may be considered '
as the pelvis: Observe that ‘they are directly connected
with ‘the pectoral’arch. How does this compare with the
dog-fish? ‘With the higher forms?-: What: would this indi-'
cate as to the place of the Teleostomi in the evolutionary
scale?’ Make a drawing of’these bones together and: one.
to show the méthod of ‘articulation. betweeii the fins ‘and
these bones: Is this joint different from that of the higher
forms? «| aA 8 a . —

_A MANUAL OF ZOOLOGY | 47

Remove the skin from the whole side of the fish by
cutting along thé back near the dorsal fins, taking care
not to injure the musculature beneath. Roll the skin
lengthwise to see the arrangement of the rows of scales
in that direction, and roll it crosswise to see the arrange-
ment of the scales and the epidermis. Look at the lateral
line from the.inside of the skin with a hand Jens. Is there
any indication of a lateral line on the musculature? Look
on the inside of the skin and on the body under the skin
with a lens for pigment cells.. In what are they situated?
Make a drawing of the muscle arrangement on the side
of the fish. Carefully pick and scrape the muscles away
so as to expose the skeleton. Take out a.few vertebrae
and attached bones over the visceral cavity. Does the fish
have ribs? What peculiarity is there in the articulation
of the vertebrae? The largest and ventral part of a verte-
bra is called the centrum. Is ‘it hollow? Notice the
canal traversed by the spinal cord. This is called the
neural cavity, and the bones forming it the neural arch.
The neural spine projects dorsally from the neural arch.
Do the neural. spines connect directly with the dorsal
fins? Sketch a dorsal vertebra and the connecting bones
side view, also end view. Take out a few vertebrae from
near the tail. How do they compare with the dorsal ver-
tebrae? On the ventral portion note the haemal arch,
for the passage of the dorsal aorta, and the ventral spine
projecting ventrally. Observe how the blood vessels are
given off. Sketch:a caudal vertebra from the side, also
from the end.

Dissect out the brain with much care by commencing
on the dorsal anterior portion. Note the nasal sacs and
the nerves leading to them. Trace the two olfactory nerves.
back to the two olfactory lobes. How do they compare
with those of the dog-fish? Back of the small olfactory-
lobes find the cerebral hemispheres constituting the cere-
brum. -Observe the immense' advance ‘of the cerebrum
here over the dog-fish. Back of ‘the ‘cerebrum note the
two round, paired ‘optic tobes constituting the largest and
the widest part of the brain. Back of these is the cerebel-.-
lum: ‘Beneath the cerebeHium and extending backward is
the medulla -oblengata. From ‘the under side of ‘the ‘brain.

48 A MANUAL OF ZOOLOGY

observe the optic and the auditory nerves. Can you dis-
tinguish an epiphysis and a hypophysis? Sketch the
brain from the top, also from the bottom. Open the optic
-lobes and the cerebrum. Are there cavities in them?
Where do they lead’ to?, Back of the eye and lateral to
the optic lobes find the cavity,.of the ear and the ear
stones. Open the eye and fina the aqueous humor, fens,
vitreous humor, retina, choroid coat, sclerotic coat, and the
cornea. How does the lens compare with‘ that, in the
dog-fish? Dissect out the eye, commencing. first in the
roof of the mouth. Between the membrane of the roof
of the mouth and the roof find the levator muscle. From
the internal posterior part: of the optic cavity.as an origin,
to the sides of the eyeball, find four recti muscles. The
two oblique muscles. of the eye have their origin at the
internal anterior part of the orbit and. extend to the upper
and to the lower parts of the. eyeball. Note the way in
which the optic nerves cross, that from, the left eye going
to the.right side of the brain, etc,

abi

1 s Bo oY Ce a

AMPHIBIA *

FROG (Rana) ;

Material is best found-during: the early spring months.
Search the shallow ponds and the grass adjoining them for
good sized frogs. Rana catesbina.(bull frog) may be ob-
tained,’ at small cost, from the. dealers, in. zoological ma-
terial. Frogs can. be. kept alive for long. periods with, very
little care. It is necessary to have a wire cage, with or
without running" water, Ifrunning water is not to be had put
some sods with growing. grass in. the cage and keep them.
moist. Place .a vessel] of water in. the cage. This water
must be changed frequently, The frogs will. need no care
as to food,:as.:they will not eat anything except, the frogs
of smaller sige .that may be.in the cage with them. On
this. account it is well, to. sort them as ito size and to wkeep
them separate. .If they. should freeze no injury is done
for if left to. themselves they, will gradually thaw out and
be.-as, active. as ever.

In-studying the frog both, living and preserved speci-
mens should be at. hand. Formalin, four per cent. makea

A MANUAL OF ZOOLOGY. 49

a good preservative for frogs. The abdominal wall must
be cut to allow the liquid to gain access to the viscera.

EXTERNAL ANATOMY—Notice the general shape
and attitude of the live specimen. Compare with a preserv-
ed specimen. Notice the color. Is there any variation
in color on the same or different specimeis? Reflect on
the mode of the frog and decide whether he is well adapt-
ed in form for his mode of living. In what respect would
the variations in color aid him in his life struggle?

GENERAL STRUCTURE—The body as a whole con-
sists of an axial portion, head, and trunk; and an appendi-
cular portion, the legs. What is the texture of the skin?
Notice whether or not the skin fits closely to the body.
Note the surface of the skin. Study the dorsal, ventral,
and lateral views of the head. Can you locate the divid- ©
ing line between the head and the body? Compare the
mouth of the frog and that of the lobster, as to position,
shape, and breadth of opening. Locate the eyes. Note
color and shape. Are the eyelids all alike? Note the diff-
erences if “any. Has the frog the power to depress the
eyes? Keep this in mind and see if you can explain it
later. The brow-spot ‘is between the eyes on a line con-
necting the anterior borders of the eyes. The nostrils
will be found anterior to the eyes. Notice the position
and shape. Can ‘they be closed? Is there any modifica-
tion of the skin around them? The tympanic membranes
are found posterior to the eyes. What is their shape? Do
they vary in size or color? Notice the tension of this mem-
prane. To what is it fastened? Study the dorsal and the
ventral surfaces of the trunk to note any difference in
shape and in color. By pressing the body between the
thumb and fingers note the hard parts or the skeleton.
Observe the hump that appears near the middle of the
back. By pressing your fingers posteriorly from this point
three hard ridges will be noticed. The two lateral ones
are the parts of the ilium. The middle one is the urostyle.
Find the anal opening at the posterior end. What is its
relative position to the posterior end of the urostyle?
Notice carefully the anterior legs. What is their direc-
tion? Can the frog reach his nose with his hand? Does

50 A MANUAL OF ZOOLOGY

the diameter of the leg vary greatly. throughout its length?
Note the upper arm, brachium; the forearm, the antibra-
chium; the hand, the manus. What is the relative propor-
tion of each of thesg parts to the length of the leg? How
many digits on the manus? Do you find a thumb,
Pollex? Note the number of joints in each digit. Would
you judge these legs to be good organs of locomotion in
the water? Why? In the posterior legs note the thigh, leg,
crus, and foot. How do these parts compare with those
of the anterior leg? Do you find a great toe, the hallex?
Make a sketch of the frog, side view as seen alive.

INTERNAL ANATOMY—The Skeleton. Study skele-
ton prepared in Wickersheimer’s fluid. Note the ‘axial
skeleton, consisting of skull; vertebral column; appendi-
cular skeleton, and limb girdles: anterior, the pectoral
girdle; posterior, the pelvic girdle.

_ The Vertebral Column—Of how many parts does it
consist? What is the general shape of each part? How.
does the urostyle compare in shape and structure with
the anterior part of the vertebral column? Near the an-
terior end of the urostyle-find two openings, foramina for
nerves to enter. Draw the urostyle from the side. The an-
terior part of the axial skeleton is made up of parts call-
ed vertebrae. How many do you find? Study them for
differences. Examine one, the third as a type, and note
that it is a bony ring with several projections. Note
the ventral portion, the body. What is its structure? On
the dorsal side is the neural arch. Note the shape as geen
from the end. Find the spinous process. On dorsal side
of each, the transverse process on the side of the neural
arch. Note their shape, size, and direction. Find the an-
terior and the posterior articular processes. Why are
they called articular processes? Are there any ribs? Draw
end and side view of a vertebra. Compare carefully the
first vertebra, the atlas, and the last, the sacrum, with
the one just studied. Can you find all the processes men-
tioned above? Do you find any modifications of these
‘processes? Find the odontoid process, a projection on
the body of the atlas. The intervertebral foramina will
be ‘noticed, by studying the entire column, on the lateral
area just below the articular process. Note the direction

A MANUAL OF. ZOOLOGY 51

of movements possible in the vertebral column as a whole.
The Skull—Describe its shape from below, above,
and from the side. Locate the eye sockets. Notice the
auditory capsule just back of the eye socket. What is
the relation of the tympanum to this capsule? Note the
lower jaw, the mandible. What is its shape?
Look for teéth. Find whether it is made up of.
one or of several parts. Meckel’s cartilage will be found
in a groove on its upper edge. Note the extent of this
cartilage. Find the foramen magnum in the posterior end
of the skull. The neural canal is a continuation of fhis
foramen. What is the relation of the cranial cavity to
this foramen? What is the shape of the condyles which
are the projections on either side of the foramen magnum?
Note the surface of the condyles. With, what bone do
they articulate? Find the cartilaginous ring upon which
the tympanic membrane is stretched. Note the nasal
bones near the anterior part of the head. Find the pre-
maxillae just in front of the nasal bones. The maxillary
bones extend backward from the premaxillae. How are
the teeth arranged? How many are there? Find the
palatine bone just under the nasal bone. Describe this
bone. The vomers are found in front of the palate bones.
Do you find teeth here?
“The Pectoral Girdle—Is made up of the clavicle,
scapula, and a sternum. What attachments to the axial
skeleton do you find? What is the relation of the scapu-
lar portion (dorsal) and the coracoid portion (ventral)
each to its neighbor on the right or the left side? Note
that the scapular portion is made up of a cartilaginous
and a bony part. The former is the supra-scapula, the
latter is the scapula. Note the coracoid bone and the
clavicle. Compare them in form. The part of the girdle
that makes up one side of the shoulder joint is the glen-
oid cavity. What bones go to make up this cavity? Note
the manner in which the clavicle is attached to the scap-
ula. ,The coracoid foramen is between the coracoid and
the clavicle. The sternum consists beginning in front, of
the omosternum, episternum, epicoracoids, sternum proper,
and the xiphisternum. Make a careful comparison each

52 A MANUAL OF ZOOLOGY

with the others and note ;whether they are bones or
cartilage.

The Fore Limb—Notice that it is made up of four
parts; the humerus, radio-ulna, carpus, and manus. “Make
a drawing of the humerus after making a careful study
of it. The proximal end of the humerus is enlarged to
form the head and articulates with the pectoral girdle
at the glenoid cavity. Observe a prominent ridge, the del-
toid ridge, ‘on the dorsal side. How do the two ends of.
the ridge differ? Are both ends of the humerus alike?
What is the shape of the radio-ulna? What would suggest
this name for the bone? The olecranon process is back
of the elbow joint. What movements are possible in the
elbow joint? How many, and what is the arrangement of
the carpal bones? Note the position of the hand on a
living frog. Compare the movements possible in the wrist
of the frog with those of your own. Bxamine the meta-
carpals. Study the phalanges. Notice carefully the pollex
or thumb, and point out any differences between this and
the fingers.

The» Pelvic Girdle—Compare this with the pectoral
girdle, in shape, and the direction in which it extends:
What is its attachment. to the axial skeleton? Make out
the following bones which are more or less tused to maka
up the girdle: the ilium, which runs nearly parallel to the
urostyle, the ischium, which forms the greater part of the
posterior half, and the pubis, which forms the ventral
portion. Note carefully the shape of each of these parts.
Find the acetabulum, the cavity into which the femur fits.
Make a drawing showing a side view of the girdle.

The Hind Limb—In what way does the femur differ
from the humerus? Compare the range of motion of. the
femur with that of the humerus. Give your reasons for
any difference. Compare the tibio-fibula with the corre-
sponding parts in the fore limb. Find the tarsus. Note
the astragulus, and tHe calcaneum. Note the direction
of motion possible in the bones of the hind foot, Do you
find a patella? Make a drawing of the bones of the hind
leg. Compare -the skeleton of the frog with as many
other skeletons as you have at hand.

A MANUAL OF ZOOLOGY 53

MUSCULAR SYSTEM—Muscles of the Ventral Body
Wall—Remove the skin of the ventral surface of the body-
and find a long muscle extending from the pubis to the
sternum, rectus abdominis. It is divided on the median
line by the linea alba, and transversely into several divis:
ions. How many?. The pectoralis is a fan shaped muscle
having its origin along the entire length of the body ta
the pubis. It may be considered in at least two parts,
the thoracic and the*abdominal, from the points of origin.
Trace it to the insertion on the deltoid ridge of the humer-
us. Just in front and partly covered by the pectoralis is
the sterno-radialis. This is a triangular shaped muscle
with its origin on the sternum and its insertion after
ending in a very long tendon, is on the radio-ulna. The
external oblique arises on the surface of the ilium and
the aponeurosis of the back and spreading out in a thin
sheet, ends in an aponeurosis ventral to the rectus ab-
dominis. Its insertion is in the linea alba. What is the.
direction of the fibers? The internal oblique lies under
the external oblique. It has its origin on the vertebrae
and the ilium and is inserted on the sternum and the linea
alba.

The Muscles of the Back—The depressor mandibuli
is a triangular muscle posterior and partly covered by the
tympanic membrane. Its origin is on the suprascapula
and the fascia of the mid-dorsal line, and it is inserted
into the angle of the jaw. The contraction of this muscle
would do what? The cucullaris is a small muscle arising
from the middle line of the exoccipital and inserted into
the dorsal border of the suprascapula. What is its direc-
tion? The infra-spinatus is-a large triangular muscle over-
lapped anteriorly partly by the next muscle. Its origin
is'on the suprascapula and its insertion is on thé deltoid.
ridge of the humerus in common with the latissimus. dor-
si. The latissimus dorsi is a triangular shaped muscle
posterior to the depressor mandibulae. It has its origin
in the dorsal fascia and-is inserted on the deltoid ridge
with the infraspinatus. The extensor dorsi communis is
the large dorsal mass of muscles. It arises from the uro-
style and is inserted into the ilium, transverse processes
of the vertebrae. and into the posterior end of the skull.

54 A MANUAL OF ZOOLOGY

What is the direction of the fibers? The intertransver-
sales are small muscles between the transverse processes
of the vertebrae. They lie beneath the preceding muscle.
The gluteus arises from the outer side of the posterior
two thirds of the ilium and is inserted into the trochanter
of the femur. What is the direction of the muscle?. ,
The Muscles of the Ventral Surface of the Head—
The mylohyoid covers the entire ventral surface of the
head just under the skin, The fibers meet on the. mid-
ventral line, and have their origin on the inner superior
border of the mandible. In the anterior angle of the man-
dible note the submentalis, a short muscle dorsal to the
fibers of the mylohyoid. The fibers have their insertion on
the inner superior border of the mandible. On either side
of the mid-ventral line is a broad, thin muscle, the genio-
hyoid, just dorsal to the mylohyoid. Its origin is at the an-
terior end and on the inner superior border of the man-
dible. The posterior end is divided and inserted on the
hyoid apparatus. The sternohyoid is really a continuation
of the rectus abdominis. The inner fibers have their orig-
in on the sternum and the outer ones are continuous with
the rectus abdominis. It is inserted between the ends of
the geniohyoid. Dorsal to the mylohyoid and the genioh-
yoid is the hyoglossus, Its origin is on the hyoid appara-
tus. This muscle can be, traced to a point anterior to the
larynx, into the tongue, and backward to the tip of the
tongue. The petrohyoids are a group of four muscles with
their origin in the auditory capsule. Extending ventrally
they pass around the oesophagus, spread out in a fan
shape upon reaching the floor of the mouth, and are in-
serted upon the hyoid apparatus. Between the tympanic
membrane and the eye find the temporalis, whose origin
_is on the dorsal surface of the head and the auditory cap:
sule, and whose insertion is on the outer surface of the
posterior end of the mandible. What is the function of
this muscle? Partly under the temporalis is found the
pterygoideus, a slender muscle with its origin on the side
of the skull and its insertion on the mandible back of that
of the temporalis very near the joint. The masseter is a
small muscle behind the temporalis and inserted just in
front of the joint on the outer surface of the mandible.

1812 13 14 WY
‘ . % NL!

FIGURE [.—1, Pectoralis; 2, Rectus Abdominis; 3, External’ Oblique;
4, Internal Oblique; 5, Mylohyoid; 6, Genighyoid; 7, Sternchyoid; 8, Submen-
talis; 9, Hyoglossus; 10, Deltoid; 11, Sterndradialiss 12, Sartorius; 13, Adduv-
tor Magnus; 14, Adductor Longus; 15, Rectus Internus Major; 16, Rectus
Internus Minor; 17, Rectus Anticus Femoris; 18, Triceps Extensor Femoris;
19, Semitendinosus; 20, Adductor Brevis; 21, Pectineus; 22, Gastrocnemius;
23, Tibialis Posticus; 24, Extensor Cruris Brevis; 25, Tibialis Anticus; 26, Epi-
sternodeltoid; 27, Levator Glavicula; 28, Flexor Tarsi Anterior; 29, Posterior
Division of the Triceps; 30, Pronator; 31, Anterior Extensor; 32, Anterior
Plexor; 33, Supinator; 34, Masseter. (After W. F. Gopeland.)

;

56 _A MANUAL OF ZOOLOGY

Muscles of the Eye Ball—The levator bulbl is a thin
sheet of muscle ventral to the eye ball. What is its func-
tion? The recti muscles consist of four separate muscles
with their origin on the inner posterior angle of the eye
socket and their insertion on the eye ball. Locate each:
rectus superior, rectus inferior, rectus externus, and rectus
internus. The oblique muscles are two in number with
their origin on the palatine bone at the anterior end of
the orbit and with their insertion on the eye ball; superior
oblique is inserted on the dorsal surface of the eye ball
in front of the rectus superior; inferior oblique passes un-
der the rectus internus and is inserted between it and the
rectus inferior. The retractor bulbi has its origin on the
parasphenoid embracing the optic nerve to the eye ball
where it is inserted. Look for it from below after remov-
ing the recti muscles.

The Muscles of the Fore Limb—The sub-suprascapula
has its origin on the ventral surface of the proximal end
of the suprascapula and its insertion on the upper anterior
surface of the scapula. The subscapula is similar in shape.
but much larger than the former. Its origin is on the
greater part of the inner posterior surface of the scapula.
Its insertion is on the head and the proximal half of the
postero-inferior surface of the humerus.

Separate the suprascapula from the scapula and re
flect it; find two broad muscles inserted on the under sur-
face of the suprascapula near. its ventral margin. The
anterior one, which is the smaller, is called the levator
anguli scapulae. The posterior division is called the
retrahens scapulae. This latter corresponds to the serra-
tus magnus in the higher forms. It has its origin on the
second transverse process and ‘on the dorsal surface of
the third, fourth, and fifth vertebrae, What is the origin
of the levator anguli scapulae? After the viscera have
been removed find an oblong muscle, the trapezius, dorsal
to the oesophagus and ventral to the extensor dorsi com-
munis. Its origin is on the exoccipital and its insertion
is on the proximal half of the ventral surface of the su-
prascapula. Press apart the deltoid muscle and the man-
dible and find a cylindrical muscle, the levator clavicula}
its insertion is the middle of the anterior border of the

FIGURE II.—1, Depressor Mandibuli; 2, Infra-Spinatus; 3, External
Oblique; 4, Internal Oblique; 5, Latissimus Dorsi; §, Extensor Dorsi Gommunis;
7, Temporalis; §, Gluteus; 9, Masseter; 10, Pterygoideus; 1], Semimembranosus;
12, Biceps Femoris; 13, Pyriformis; 14, Iliopsoas; 15, Obturator; 1§, Rectus
Internus Minor; 17, Vastus Externus; 18, Triceps Extensor Femoris; 19, Quad-
ratus Femoris; 20, Anterior Flexor; 21, Middle Flexor; , 29 Posterior Flexor;
23. Posterior Exner 2s oe 25. Rene she this Triceps; 97,

; ibialis Anticus; 29, Gastrocnemius; $0, Vastus Internus.
Reonenes a; ne After W. F. Copeland.)

58 A MANUAL OF ZOOLOGY

scapula. What is its origin? Ventral to the latissimus
dorsi and posterior to the scapula find 4 muscle, ‘the op-
ponens levator clavicula, similar in shape to the former.
Its origin is on the'outer end of the third or fourth trans-
verse process, and its insertion is on the posterior border
of the scapula. Immediately antero-external to the sterno-
radialis find a narrow muscle, episterno-deltoid. Its origin
is on the outer edge of the episternum and its insertion
is on the posterior surface of the deltoid ridge near the
distal end of the humerus. Note the relation of the muscle
to the sterno-radialis. The deltoid is located dorsal to the
‘episterno-deltoid and ventral to the infraspinatus. Its orig-
in is on the anterior edge of the scapula, and its insertion
is on the deltoid ridge, almost its entire length. Three
muscles comprise the group known as the triceps brachia.
They are all inserted in one tendon on the olecranon pro-
cess of tne radio-ulna. Trace each division to its origin.
Two thick muscles invest the insertion of the deltoid.
They may be called the pronator, and the supinator.
Trace out both the origin and the insertion of these mus-
cles, and decide why these names are given to them. The
extensor muscles are located on the externo-ventral sur-
face of the radio-ulna. Two divisions of these muscles
may be made, an anterior and a posterior. On the anter-
ior dorsal surface of the radio-ulna or ante-brachium are
found the flexor muscles. Three divisions of these mus-
cles may be made. From their position and direction
what would be the result of their actions?

Muscles of the Hind Limb—In ‘the act of swimming
or jumping the frog extends his hind legs backward uitil
they occupy a position parallel to the longitudinal axis of
the body. Specimens that have been preserved in alcohol
or formalin are not usually found thus, but for purposes
of description this longitudinal position will be assumed.
The surface along which lie the extensor muscles of the
legs, the patellar surface of the knee, and the upper surface
of the foot, will be called the outer or external surface,
The surface opposite along the bend of the knee and cov-
ered by the flexor muscles, will be called the inner or
internal surface of the leg. Concerning the surfaces

Figure III.

FIGURE IIl.—1, Submentalis; 2, Tongue; 3, Hyoglossus; 4,
Levator Glavicula; 5, Petrohyoids; 6, Glottis; 7, Oesophagus.

FIGURE IV.—1, Inferior Oblique; 2, Superior Oblique; 3,
Levator Bulbi; 4, Rectus Internus; 5, Rectus Externus; 6, Rectus
Inferior; 7, Temporalis; 8, Pterygoideus; 9, Auditory Gapsule; 10,
Petrohyoids; 11, Gucullaris or Trapezius; 12, Intertransversalis; 13,

Retractor Bulbi. (After W. F. Copeland.)

60 A MANUAL OF ZOOLOGY

separating these two surfaces, the upper is the dorsal or
superior, and the under is the ventral or inferior surface.

The Superficial Muscles of the Ventral Surface—The
sartorius extends along the entire length of the femur ex-
ternal to the middle of the ventral surface. Its origin is
on the symphysis of the ilium and it is inserted on the
inner tuberosity of the tibio-fibula and in the aponeurosis
of the knee joint. One of the largest muscles of the thigh
is the adductor magnus. It runs along the inner border
of the sartorius under which it dips at the distal end. It
originates on the pubis and the ischium and is inserted on
the. distal end of the femur together with the adductor
fongus. External to and mostly covered by the sartorius
is the adductor longus. It is a ribbon shaped muscle be-
tween the sartorius and the vastus internus. Its origin
is on the ilium anterior to the acetabulum and it is in-
serted with the preceding muscle. The rectus internus
major is a large muscle situated internal to the origin of
the adductor magnus and the insertion of the sartorius.
What is its origin and its insertion? The rectus internus
minor lies internal to the rectus internus major on its ven-
tral border. Its origin is on the symphysis of the ischium
and is inserted on the inner side of the tibio-fibula just
below its head. a

Deep Muscles of the Ventral Surface of the Thigh—
The semitendinosus arises by two heads, one on the sym-
physis of the ischium and the other on thesymphysis pubis.
The two heads unite near the middle of the femur and
are inserted into the knee joint and the proximal inner
surface of the tibio-filbula. The pectineus has its origin
on the symphysis pubis and is inserted on the proximal
half of the posterior border of the femur. This muscle is
dorsal to the vastus internus and the adductor magnus,
Internal to the pectineus and dorsal to the adductor mag-
nus is a short broad muscle, the adductor brevis, Its orig-
in is on the symphysis pubis and the ischium posterior to
that of thé pectineus.

Superficial Muscles of the External Surface of the
Thigh—The triceps extensor femoris lies on the external
surface of the thigh. It originates by three heads:
vastus externus, vastus internus, and the rectus anticus

A MANUAL OF ZOOLOGY 61

femoris. These three heads unite near the middle of
the thigh into the tendon of the patella, whose insertion is
on the ventral proximal end of the tibio-fibula. The vastus
externus is the most dorsal of these three heads, with its
origin on the posterior surface of the ilium. The vastus
internus lies nearer the ventral surface, ventral to the
rectus anticus femoris and external to the sartorius with
its origin on the anterior surface of the head of the femur
and the acetabulum. The rectus anticus femoris is the
middle head with its origin on fhe ventral posterior border
of the ilium. ue

The Superficial Muscles of the Dorsal Surface of the
Thigh—The gluteus is a thick muscle with its origin on
the outer posterior surface of the ilium, and with its
‘insertion on the posterior surface of the cartilage about
the head of the femur. The largest muscle on the dorsal
surface is the’ semimembranosus. It is bounded by the
vastus externus and the rectus internus minor. It origin-
-ates on the ischium and is inserted on the knee joint in
its aponeurosis. The long spindle shaped muscle with
two bellies with a common tendon at the proximal end
is the biceps femoris. It is bounded by the triceps femoris
and the semimembranosus, and has its origin near the dorsal
edge of the acetabulum. A part of this muscle is inserted on
the dorsal proximal haif of the femur and another part is in-
serted on the knee joint and the dorsal part of the proxi-
mal end of the tibio-fibula. The pyriformis is a small
muscle with its origin on the posterior end of the urostyle
and its insertion on the shaft of the femur.

Deep Muscles of the Dorsal Surface of the Thigh—
After removing the vastus externus, the semimembrano-
sus, and the biceps femoris, the ilio-psoas will be seen in
contact with the ventral border of the gluteus. Remove
the gluteus and find the origin of this muscle on the inner
posterior surface of the ilium internal to the acetabulum.
Follow it around the ventral border of the ilium, anterior
to the acetabulum, to its insertion on the dorsal border
of the femur. Ventral to the origin of the semimembrano-
sus and dorso-posterior to the obturator find the quadra-
tus femoris. It originates on the ilium near the acetabu-
lum and is inserted on the proximal third of the femur.

62 A MANUAL OF ZOOLOGY

The obturator has its origin on the symphysis of the
ischium and its entire lateral surface and is inserted
above the head of the femur.

Muscles of the Leg—On the dorso-posterior surface
of the tibio-fibula note ‘a large muscle, the gastrocnemius.
It has its origin by two heads passes around the calcan-
eum and is inserted in the fascia of the plantar surface
of the foot. This is the tendon of Achilles. The tibialis
posticus is a slender muscle between the tibalis anticus
and the gastrocnemius. It has its origin along the en-
tire inner surface of the tibio-fibula, and is inserted on
the dorsal proximal end of the astragalus. The tibialis
anticus is a muscle opposite the gastrocnemius. It has its
origin on the femur near the knee joint, divides near the
middle of the leg, and is inserted by two tendons, one
on the astragalus and the other on the calcaneum. The
peroneus is a long muscle extending the whole length
of the tibio-fibula between the tibialis anticus and the
gastrocnemius. Its origin is on the distal end of the fem-
ur and it is inserted on the calcaneum. Between the
tibialis anticus and the tibialis posticus find a small muscle,
the flexor cruris brevis. Its origin is by a long tendon
which lies in a groove on the surface of the tibio-fibula.
It is inserted along the shaft of the tibio-fibula. The
smallest muscle of the leg is the flexor tarsi anterior. Its
origin is on the anterior part of the distal half of the tibio-
fibula and its insertion is on the proximal end-of the as-
tragalus.

DIGESTIVE SYSTEM—The Buccal Cavity—Open the
mouth as wide as possible. Note the maxillary teeth on
the upper jaw, two small patches of teeth in the middle
line, the vomerine teeth. Look for two small holes later-
al to and slightly in front ofthe vomerine ‘teeth, the
posterior nares, Is there any connection of the nostrils
and the posterior nares? In the posterior ‘part of the
mouth two larger holes are found one on either side, the
eustachian tubes. What relation do these tubes have to
the tympanic cavity? Demonstrate with a bristle. How
do the eye balls effect the shape of the roof of the mouth?
Are there any teeth on the lower floor of the mouth?

A MANUAL OF ZOOLOGY 63

What is the shape and the attachment of the tongue?
Locate the glottis or the opening into the Jarynx,

‘The Abdominal Viscera—Lay the frog on its back
and open the- body cavity. On the mid-ventral line is
found the heart inclosed in the pericardium, Behind the
heart find the liver. What is its color? What is its size
as compared with the other organs in sight? Note its
shape. Dorsal to the liver and often hidden by it are the
lung sacs. Demonstrate the connection of the lung with
the larynx. Behind the large intestine note the convoluted
tube, the small intestine. Find the bladder, a thin walled,
bilobed sac in the posterior end. of the. body cavity. In
the female two large bodies consisting of a mass of eggs’
are the évaries. Trace the oviducts from these, In the
male two yellow bodies fastened to the dorsal wall, the
testes, will be found. Examine in detail the alimentary
canal. The duodenum opens from the stomach and con-
tinues into the small intestine which opens into the large
intestine. Notice the pyloric constriction between the
stomach and the duodenum. Notice the manner in which
the small intestine opens into the large intestine. Follow
the large intestine to the cloaca. ‘Note the openings into
the cloaca: the renal, the genital ducts, ana the bladder.
Between the left and the right lobes of the liver, find the
gall bladder; from this trace the gall duct to its opening
into the duodenum. This opening will be found about one
half inch beyond the pylorus.. Locate the pancreas in a
loop between the stomach and the duodenum. The ducts
from the pancreas open into the bile duct on their way
through the pancreas. In the dorsal body wall close to
the middle line will be found two fiat, oval bodies, the
kidneys. Note a white tube leading from each kidney to
the cloaca, the ureter. . Near their opening into- the
cloaca find two pouch like sacs, the vesicula seminalis,
on each ureter in the male. Note small red patches on
the ventral ‘surface of the kidney, the’ adrenal bodies.
The fat bodies are seen as two bright yellow tufts fasten-
ed to the dorsal wall and appear on the surface just behind
the liver. In the mesentery near the commencement of
the large intestine find a dark red body, the spleen. Make

64 _ AMANUAL OF ZOOLOGY

a sketch of the alimentary canal with all of its accessory
organs.

THE CIRCULATORY SYSTEM—Pith a frog. ~Lay
him on his back and open the ventral wall to expose the
heart just under the sternum. Study the beat of the heart.
Do all parts of the -Heart beat at the same time? De-
scribe the heart’ beat. Note the four divisidns of the
heart: the anterior part, the auricles; the ventricle; the
truncus arteriosus. How many auricles? What is the
relation of the ventricle to the auricles? The truncus ar-
teriosus arises from the right anterior border of the ven-
tricle. Trace this across the auricles. Dorsal to the heart
find a thin walled sac,~the sinus venosus. How many
vessels open into it? These are called venae cavae. Note
the pericardium. What is its relation to the heart? To
what is it fastened?’ What does it contain? Dissect the
veins first on account of their being filled with blood; this”
gives them'a dark color. Disseect from the ventral surface
being careful not to injure the veins. Clean and pin them
out carefully as you go along. ,

Veins Opening Into the Sinus Venosus—Into the right
side opens the right anterior vena cava.’ This carries the
blood from what region? It is formed by three veins:
the external jugular, the innominate, and the subclavian.
The first receives blood from the tongue through the
lingual vein and from the lower jaw through the mandi-
bular véin. The second gets blood from the interior of
the skull by the internal jugular and from the arm by the
subscapular vein. The third’ gets blood from the fore leg
by the brachial vein, and from the skin and back by the
musculo-cutaneous vein. Compare the left anterior. vena
cava with the right.

The posterior vena cava may be traced from between the
kidneys forward and dorsally to the liver, and finally to
its opening into the posterior end of the sinus. It receives
blood from the hepatic veins. How many are there? Trace
the renal veins. Into what do they empty? Trace also the
ovarian, and the spermatic veins. Locate the pulmonary
vein. Note that it is formed by two veins, one from each
lung, and. that it empties directly into the left auricle.

A MANUAL OF ZOOLOGY 65

Make'a diagram representing the venous system as far as
studied.

What is meant by a portal system? It will be noted
that the frog has two portal systems: the renal and the
hepatic. Trace back the anterior abdominal vein to the
posterior part of the body and find that it receives blood
from the femoral veins. It will be found that the femoral
vein branches, one branch going to the kidney; this is the
renal portal vein. The hepatic portal system is formed
partly by the anterior abdominal vein, and partly by veins
returning blood from the alimentary canal. Look for the
hepatic portal vein. Near the point where the branches
of the anterior abdominal veins go off to the liver, look
for the gastric vein, the intestinal veins, and the splenic
vein. Make a diagram of the portal system.

Arteries—Distend the oesophagus with a roll of paper
or with a pencil. Clear off the arteries as in the case of
the veins. Note the division of the truncus arteriosus into
two branches, each of which subdivides into three arches:
the carotid arch, the systemic arch, and the pulmo-cuta-
neous arch. The most anterior of the three arches is the
carotid arch. It gives off a branch to the tongue, the
lingual artery. Find the carotid gland on this branch.
Trace the carotid artery around the oesophagus to its
dorsal surface and thence to the skull where it divides
into twobranches, the external and the internal carotid
arteries. The middle of the three arches is the systemic
arch. Trace this around the oesophagus and note that it
joins with its fellow from the opposite side in the region
of the kidneys to form the dorsal aorta. Note four
branches given off before this union: the lingual artery,
which supplies blood to the larynx, the oesophageal, the
occipito-vertebral, and thé subclavian artery. Follow it
pack of the union to the dorsal aorta and find four
branches: the coeliaco-mesenteric. It supplies with blood
the urogenital arteries, the lumbar arteries, hemorrhoidal
artery. Note the division of the aorta into the great ar-
teries, the iliac arteries. These supply blood to what?
The most posterior of the three arches is the pulmo-cuta-
neous arch. It divides at about the level of the carotid

66 A MANUAL OF ZOOLOGY

gland into two branches, the cutaneous artery, and the pul-
monary artery. To what do they. supply blood? ~Make a
diagram of the arterial system.

Heart—Cut off the blood vessels some distance from
the heart. Insert bristles of different color into the carotid
arch, the aortic arch, and the pulmonary arch. Pin the
heart down dorsal side up. Dissect under water, cutting
through the ventricle and other parts of the heart to
expose their cavity. Study the ventricle. What is the
thickness and texture of its walls? Compare with' the
auricles and the truncus arteriosus. Is the ventricle di-
vided? Look for the auriculo-ventricular aperture on the
right of the specimen. Are there valves here? How many?
Name them. Notice their connection with the ventricles.
Notice the inter-auricular septum. What is its structure,
direction, and position with reference to the truncus arter-
iosus and the auriculo-ventricular aperture? Locate the
opening of the sinus venosus, in the right auricle, the
sinu-auricular aperture. Find the opening of the pulmo-
nary veins, close to the septum, near the top of the left
auricle. What relation does the truncus arteriosus have
with the ventricle? Notice the longitudinal valve in the
truncus. Notice the relation of the carotid, the aortic, and
the pulmonary arches of the truncus. Make a diagram of
the heart, and its connections. On a live frog notice the
pesterior lymph hearts on ‘either side of the urostyle.
Study the meaning of the lymphatic system, wh&t it con-
sists of, and what relation it has to the circulatory system.
Make a mount of frog’s blood in normal salt solution.
Note the two ane of corpuscles. How do they compare
in number? What is their shape? Run some acetic acid
under the cover glass. What is the effect? Make a mount
of human blood as above; compare the corpuscles in every
respect with those of the frog. Pith a frog and prepare
the web of his foot for the microscope stage. Study the
circulation of the blood: Can you distinguish arteries,
‘capillaries, and veins? Study carefully “with: the high
power, if you have- to use the mesentery, the corpuscles
and their movements. Are they all in closed vessels?

» What exceptions do you find? Make’a drawing represent-
ing the corpuscles of the frog and: those of man.

A MANUAL OF ZOOLCGY 67

THE NERVOUS SYSTEM—Cut away the muscles on
both sides of the spinal column. Cut off the dorsal portion
of the skull and the vertebrae, being careful not to de-
stroy the contents of the cavities exposed. Notice thaf the
nervous system consists of two parts: the central and the
peripheral portions. The central portion consists of the
brain and the spinal cord. Examine carefully the dorsal
surface of the brain. Note the olfactory lobes, the most
anterior portion; cerebral hemispheres, immediately pos-
terior to the olfactory lobes; the thalamencephalon, poster-
ior to the cerebrum and between its diverging ends; the
optic lobes, two oval bodies posterior to the former; note
the pigment in the pia mater over the optic lobes; the
cerebellum, a narrow strip or band posterior to the optic
lobes; the oblongata, immediately posterior to the cerebel-
lum and continuous with the spinal cord. Locate the chor-
oid plexus, a thick membrane covering the thalamencepha-
lon. Locate the pineal body. The optic thalmi are the thick-
ened sides of the thalamencephalon. Slice off the top of the
brain without removing it from the skull, thereby exposing
several cavities, the ventricles. The most anterior and
lateral cavities are the lateral ventricles. What is their
extent? The cavity in the thalamencephalon is the third
ventricle. Note its connection with the lateral ventricles
through the foramina of Monro. Locate the infundibulum
and the pineal body. The aqueduct of Sylvius leads from
the cavity known as the third ventricle.to the fourth ven-
tricle. Notice the cavity in the optic lobes. Cut the me-
dulla at the level of the posterior part of the skull and
carefully remove the brain, keeping in mind that there
are a number of important things on the ventral surface
that may be easily destroyed. Find two large nerves that
appear to cross, the optic chiasma. Notice a depression
just posterior to the optic chiasma, which causes a swell-
ing on each side, the tuber cinereum. If the pituitary body
has been left in the skull in taking out the brain, the torn
end of the infundibulum will be seen in connection with
the posterior part of the tuber cinereum. Find the crura
cerebri at the base of the optic lobes. Notice a fissure -
continuous with the ventral fissure of the spinal cord, °
the ventral fissure of the brain. Is the spinal cord uniform

68 A MANUAL OF ZOOLOGY

in size? Notice several pairs of nerves coming off from
the spinal cord. How many are there? What makes up
each pair of spinal nerves? The spinal nerves may be seen
better by cleaning the ventral cavity. - They will appear as
white cords extending to different parts of the body.
Work them out carefully and note that there are ten of
them. Work out the spinal column and locate the spinal
ganglia. Upon which root do you find them? Locate the
sympathetic nervous system. Is there any connection with
the spinal nerves? Note, locate, and name the-ten-pairs of
cranial nerves. Study prepared slides of nerve tissue,
spinal cord, and isolated nerve cells for the microscopic
structure of the nervous system. Distinguish between
medullated and nonmedullated nerve fibers. Note the axis
cylinder, nodes, and internodes. Pick out several cells

-in the slide and compare them in shape. In the spinal
cord note the position of the gray, and the white matter..
What constitutes each? Study a section of the spinal gang-
‘lion. Of what does it consist? What membranes cover
the central nervous system? Make a drawing of the dorsal
and one of the ventral.surfaces of the brain.

THE EYE—Note the following. structures before mak-
ing any dissections. The shape, the sclerotic coat, the
cornea, the iris, the pupil, the optic nerve. With a sharp
knife divide the eye ball into an anterior and posterior
half. Note the lens in the anterior portion. Locate the
anterior chamber. What does it contain? The vitreous
humor fills the posterior chamber. ‘Describe the vitreous
humor. Locate the choroid coat as a lining for the scler-
otic coat. What is its color?. Note a transparent mem-
brane lining the eye ball, the retina. At what point is it
attached to the eye ball? Dissect an eye of a sheep or of
an ox and compare in every respect with that of the frog
as above. Make a diagramof the antero-posterior section
of the eye and name all of the parts. Study prepared
slides of the anterior and the posterior quarters of the eye.
Work out the meaning of all the parts shown, especially
the ciliary muscles, the iris, the cornea, the coats of the
eye, the optic nerve. Note carefully their structure..

THE EAR—Study a series of sections of the frog’s
head through the ears, made by decalcifying, embedding

A MANUAL OF ZOOLOGY ' 69

c
in- paraffin, and cutting in a microtome. Stain “in toto”
in borax or para carmine. Note the following: the peri-
otic capsule, the vestibule, the ductus endolymphaticus,
the semicircular canals, the auditory nerve, the eustach-
ian tubes, the tympanic membrane, the columella.

THE REPRODUCTIVE SYSTEM—In a male specimen
locate the testes as a pair of yellow, oval bodies, on the
ventral surface of the kidneys. The vasa efferentia are
several tubes leading from the testes to the kidneys. They
carry the sperm cells. into the kidneys from which they
pass through the ureters which act as vas deferens. They
finally open into the cloaca. Locate the vesicula seminalis
as a large pouch on the vas deferens before they open into
the cloaca. Note the following openings into the cloaca:
the large intestine, the ureters, and the bladder. What is
the nature of the bladder? _ Are there any openings out of
it? Compare the female frog with the above. Locate the
ovaries. Trace out the oviducts. Does the female frog
have ureters as well as oviducts? Compare with the
male. Note the openings into the cloaca: the- bladder,
the aviducts, the ureters. How does the number of open-
ings compare’ with those in the male?

4 :
REPTILIA

The Turtle,

NOTE—The work on the turtle should be one of con-
tinuous comparison with the lower forms, especially with
the frog. ; ;

EXTERNAL STRUCTURES—The shell of the turtle
consists of a dorsal part, the carapace, and a ventral por-
tion, the plastron. .These are united at the side by the
bridges. The carapace is made up of a definite number of
central plates surrounded by a regular border of smaller
ones. What is the number of each kind? How many
plates in the plastron? Is it divided into distinct parts?
Is it movable? What is the purpose of the shell? Can
the head, tail, and legs be entirely drawn into the shell?
Make a sketch of the ventral surface of the animal. Note
the general shape of the head. Find the nostrils. Into
what do they open? Note the size, shape, and position

70 A MANUAL OF ZOOLOGY

of the eyes. Do they have eyelids? Is the iris colored?
Is there a nictitating membrane? Do you find indications
of ears on the outside of the head? Open the mouth and
notice the beak. Do you find any teeth? Find the opening
into the trachea and the posterior part of the floor of the
mouth. Behind this find the opening into the oesophagus.
Notice how the head and the neck can be withdrawn into
the shell and become encased in folds of skin surrounding
the neck. How does the length of the neck compare with
that of the animals already studied? Note the cavities
in the sides of the body into which the legs and the tail
may be drawn. Do you find scales on the legs, neck, or
tail? Find well developed claws on each digit. How many
are there on each foot? Are they web-footed? Cut through
the bridges with a bone forceps. Cut the plastron loose
from the skin and other attachments. After removing the
plastron notice the arrangement of the muscles attached
to its under side. Separate them carefully and observe
that they are arranged in pairs and determine the action
of each pair as nearly as possible. Dissect them away
so as not to disturb the underlying structures. Over the
ventral part of the body the peritoneum will be found.
Observe that the pectoral girdle seems to be separate
along the mid-ventral line. Dissect away the muscles
covering them. Then putting the thumbs under them
and twisting the fore legs at the same time, they may be
turned forward out of the way without injuring them. Back
of the posterior edge of the pectoral arch a little to the
right of the medial line find the heart, inclosed in a tough
membrane, the pericardium. Open this and observe the
, large ventricular part of the heart, anterior to which is a
pair of distinctly separate auricles. From the antero-ven-
tral part of the ventricle observe the arteries passing be-
tween the auricles. Notice that what appears to be the
main trunk given off from the ventricle is in reality com-
posed of a number of distinct arteries bound together. By
careful dissection demonstrate this point. Is there any
indication. of a conus arteriosus? Dorsal to the auricles
is the sinus venosus. Remove the heart by severing the
arteries about one eighth of an inch from the heart, and
the veins immediately back of the sinus.

A MANUAL OF ZOOLOGY 71

Preserve the location of the arteries. and veins by
putting bristles in them. How many arteries do you find?
Cut off the end of the ventricle of the heart. Is there
evidence of two chambers? Open the sinus and note the
Manner in which it opens into the auricles. Is there an
opening from the sinus into each auricle? Are there valves
there? Put bristles into the stumps of the arteries leading
into the heart, and then dissect along them until you find
where they lead. Open tae ventricle and see if you can
find any evidences of a partition there, Is it complete?
Are there any valves between the auricles and the ventri-
cles? Sum up the differences between the heart of the
turtle and that of the frog. Are there any evidences of a
diaphragm in the turtle? Beneath and to the side of the
heart find the large liver. With bone forceps remove a
part of the carapace until the viscera is more accessible.
How many lobes has the liver? On which side is the gall
bladder? How does the liver compare in shape and in po-
sition with the other forms that you have studied? How
do you account for any differences? Begin at the edges
of the liver and carefully pick it away, noticing to what it
, is fastened, and also the large hepatic veins, one from
each lobe of the liver leading into the sinus. Remove
the skin from the front part of the neck and find the
trachea. , Down which side of the neck does it go? Work-
ing from the side and being careful not to cut veins and
arteries, trace it downashort distance. Does it branch?
Note the.manner in which it enters the lungs and the very
peculiar structure of the _ lung. Trace the ar-
‘teries leading from the heart. The one lying on the left
is the pulmonary artery. The one next to this is the
right aorta, and the one farthest to the right is the left
aorta. The two aortae cross one another a short distance
from the heart. The right aorta, close to the heart, gives
off the innominate artery, which almost immediately gives
off the right and the left subclavians, and then divides
into the carotids. These latter pass into the skull through
a foramen. Trace all these points out. Trace the right,
and the left aorta, noticing that they pass backward over
the right and left bronchi respectively and communicate
with one another. From this point they become the dorsal

72 A MANUAL OF ZOOLOGY

aorta, which, after giving off branches to the kidneys and
the ‘reproductive organs, branches into the right and left
common iliacs. Before joining the right aorta the left
gives off branches to the stomach, the pancreas, and the
mesentery. The pulmonary artery divides near the ventri-
cle into a right and a left branch. Trace these branches
to the lungs. Notice that they run along by the side of
the pulmonary veins, which open into the left auricle.
If the specimen is a female a large ovary with eggs in
various stages of development will be found immediately
dorsal and posterior to the liver. Are there any indica-
tions of two ovaries? Can you find a way by which the
eggs might escape from the body? About how many eggs
are there?’ On each side of the ovary notice curiously
folded bodies. These are the fimbriated ends of the ovi-
ducts. Trace them backward. Where do they open? How
do the eggs get into them? How are they fastened to the
pody wall? Have they any connection with each other?
Slit open the oviduct to near its posterior end and note
the character of its mucosa. The oesophagus lies back
of the trachea and is inclined somewhat to the left of the
median line. How does it compare.in length with that
in the frog? Beginning near the mouth, slit open the ali-
mentary canal, in situ, until you are convinced by the
character of the mucous membrane that you have passed
through the oesophagus and the stomach into the small
intestine. Compare the mucosa so far with that in the
two fishes and the frogs you have examined. Which is
the better way to determine the extent of the stomach, the
external form or the internal structure? What is the shape
of the stomach? How does it compare with the dog-fish?
The perch? The frog? In which of these forms is the
pyloric valve most highly developed? Where would you
look for the pancreas in any vertebrate? Carefully dis-
sect it away from the intestine to find the opening ot its
duct. How are the intestines held in place? Trace back
the small intestine, unraveling and slitting it open, until
you pass into the large intestine. Could you tell by the
character of the mucosa the limits of the small intestine?
Trace back the large intestine by slitting it open until you
come to the cloaca. Now open the cloaca along one side.

A MANUAL OF ZOOLOGY 73

Find the opening from it into the large intestine. Find
the opening into the urinary bladder ventral to-this. In
a female specimen the openings into the oviducts will be
found in the top of eminences on. each side. In male
Specimens slits in the same relative position mark the
openings of, the vas deferens. Put bristles into them and’
trace them back to the testes which lie a short distance
in front of the pelvis. Attached to each of the testes is a
dark colored mass, the epididymis. Attached to the inner
ventral side of the cloaca is to be found the external gener-
ative organs of the male. Along its dorsal border is a deep
groove, the urethral groove. Make a diagrammatic sketch
of the digestive, the urinary, and the reproductive systems,
showing the general form and relations. Near the junc-
tion of the small and the jarge intestine find the small round-
ish spleen suspended in the mesentery. Underneath the
posterior end of the lungs on each side of the median
line find the lobulated kidneys. Trace the ureters leading
from their ventral surface. Do they lead into the bladder?

Pull out the head and notice the large muscles at-
tached to it. Find their origins and insertions. Cut them
from their attachments to the head. Note the manner in
‘which the neck is bent if the animal was killed with the
head retracted. How would the muscles act in order to
protrude or retract it? Break the spinal column as far
back as it is free. Cut all attachments and remove the
head. Posterior to the angles of the mouth you will find
the tympanic membranes. How do they compare with
those of the frog? Remove the skin over them. Notice
the white cartilaginous ring inclosing’ a round opening
over which is stretched a cartilage-like membrane which
seems to be more dense in the middle and membranous
at the edges where it attaches to the white ring. Cut
around the inside of the ring so as to free the tympanum.
Pull up one edge of it and notice a slender column leading
from it back into the ear cavity. The column and its outer
expanded tympanic part are together called the columella.
At the lower edge of the cavity will be found the very
narrow eustachian tube leading to the back part of the side
mouth cavity. Demonstrate this by working both from the
mouth and the eet side. Follow carefully the columella,

74 A MANUAL OF ZOOLOGY

, breaking through the floor of the bone cavity of the middle
’ ear. The inner end of the columella expands into a small
disk, which fills the foramen ovale, which leads into the

vestibule of the inner ear. Enlarge this opening very care--.

fully and you will find the semicircular canals. Dissect
out the eye, noting the following points: the nictitating
membrane, the lachrymal gland ventral to the posterior
angle of the eye in the orbit (what is its position in man?),
the colored iris, the transparent cornea, which is surround-
ed by a peculiar cartilage-like differentiation of the scler-
otica. Open the cornea carefully and observe the aqueous
humor and how the iris is spread out. Take out the lens.
How does it compare with that in the fish and in the frog?
Back of the lens find: the vitreous humor, the retina, the
choroid coat, and the entrance of the optic nerve. What
separates the two eye orbits? Open.the olfactory cavities.
_Are they lined with any sort of epithelium? How do they
compare with that in the dog-fish and in the teleost?

Dissect out the brain very carefully, beginning with
the already exposed ends of the olfactory nerves. ‘Note
or the dorsal aspect the olfactory lobes, the comparatively
large cerebral hemispheres, the pineal gland, or epiphysis,
the corpora bigemina (optic lobes), the cerebellum, the
medulla oblongata, and the fourth ventricle. On its ven-
tral aspect note the olfactory lobes, the optic chiasma, the
optic nerves, the optic tracts, the pituitary body, the in-
fudibulum, the thalamencephalon, the crura cerebri, and
the anterior pyramids of the medulla: oblongata. Make
drawings of the dorsal and of the ventral parts of the
brain to show: the preceding points.

Dissect out a portion of the. spinal cord. How does
it compare with the other forms? How many neck verte-
brae are there? Dissect out and clean all of the neck
vertebrae noting particularly the manner of their articula-
tions. Make a note of the different ways they articulate.
Dissect out some of the caudal vertebrae and note their
manner of articulation. Dissect out the pectoral girdle. Note
the glenoid fossa at its outer extremity for articulation with’
the head of the humerus. Articulating with this latter are
the radius and the ulna. Are they separate bones? How

A MANUAL OF ZOOLOGY 75

do they compare with those in the frog? Dissect the pel-
vic girdle. Find the femur. Are the fibula and the tibia
distinct? “Find the astragalus and the os calcis.

AVES.
English Sparrow (Passer domesticus.)

EXTERNAL FEATURES—Take some time to note
all the ways that come to you readily in which the bird
differs from other forms studied. This should be a test
of your powers of observation and comparison, and should
be done before your attention is called to the differences
and the likenesses. Note the beak, composed of the upper
and lower mandibles, at the front part of the head. Is
there any resemblance to that of the turtle? Find the
nostrils. How is their external opening protected? Do
they open into the mouth? In front of the eyes at the
base of the beak find the rectal bristles. Note the position
of the eyes. Can a bird see an object with both eyes at
once? Demonstrate the nictitating membrane by working
with a tenaculum in the anterior corner of the eye.

Associate the following names, much used in the de-
scription of birds, with the appropriate parts of the body.
The front part of the head is the forehead, the top, the
crown, the back part, the occiput, the back part of the
neck, the nape, the front part, the throat. In the male the
throat is black. Between the corner of the eye and the
corner of the mouth is the lore. At the base of the lower
mandible is the chin. Find the ear. Are the feathers cov-
ering it different from the others? The dorsal portion of
the bird is the back. The narrow portion in front of the
tail is the rump. The large, stiff tail feathers are the
rectrices. Overlapping them dorsal are the upper tail
coverts, and ventrally, the under tail coverts. The pos-
terior ventral part of the body is the belly, and the anter-
ior, the breast. Stretch out a wing. How many general
divisions can you feel? The long feathers on the most dis-
tal portion are the primaries. “On the middle portion are
the secondaries. The short feathers overlapping the pri-
maries and the secondaries are the primary and second-
ary wing coverts, upper and lower. At the angle of the
outer joint is a little bunch of feathers on the pollex or

76 A MANUAL OF ZOOLOGY

thumb. ‘On the under part of the wing near the junction
with the body are the soft axillar feathers. Work the wing
back and forth and note the way in which the feathers
overlap the large surface of the expanded wing and its
compactness when folded. From the inside the toes are
numbered as first, second, third, and fourth. The first
opposing the other three. How many joints are there in
each one? A sparrow when standing rests on its toes.
Its heel is at the joint between the scaly and the feathered
portions. The scaly part extends from the toes up to the
tarsus. The next section is the tibia and corresponds to
the leg in the higher forms, while the proximal section
corresponds to the thigh. Does the scale-covered foot
suggest a close relationship to such reptiles as the snake?
Does the beak suggest the beak of the turtle? Look up
the meaning of the word sauropsida. Are all parts of the
foot covered with scales? Extend the limb at the heel
joint and notice the position the toes take. Now flex the
same joint and note the position they take. Could the
bird fly from the place upon which it was perched when
this joint was flexed? How doés it sleep on its: perch
without falling off? -Make a drawing of the side view of
the bird naming all the ‘parts indicated,

Examine one of the large feathers. The tubular por-
tion inserted in the skin is the quill. The long, four-sided
part distal to this is the rachis. On the other side of this
is the vein or web. The vein is composed of filament-like
barbs lying close together side by side. On the sides of
the barbs are the barbules. Pull off a few barbs and soak
them in 95 per cent alcohol, and then examine them under
the low power. On the under side of the rachis note a nar-
row groove running lengthwise. With a pin follow it towards
the proximal end until you .come to a little hole leading
into the quill. This is the umbilicus. In the end of the
quill you will find an opening. What is the use of this?

Pluck a feather from the back or breast and note the
peculiar difference between it and a large feather. HExam-
ine the rictal bristles under the low power. Examine
«a hair from your head. What is your conclusion as to
the rictal bristles? Beneath the body feathers you will
find downy filament-like feathers. Look at these under

A MANUAL OF ZOOLOGY 77

the microscope. Are there. any true hairs on the bird?
Pluck a part of the body bare. Are all parts equally cov-
ered with feathers? Is there any regular arrangement of
feathers to be deduced from the appearance of the plucked
portion? Remove the upper tail coverts and note the large
oil gland. What is its use? Slit open the skin from the
chin to the cloacal opening, and carefully remove it. Down
the front of the neck note the trachea, To the right of
this find the oesophagus. Open the mouth and inflate the
crop, a bag like expansion of the oesophagus by blowing
into the oesophagus with a blow pipe. What is ‘the use
of the crop? Find the jugular veins and the vagus nerve
in the neck. In the median line of the chest find the keel
of the sternum. The sides of this serve as attachments
for the pectoralis major and minor muscles. Are they
much developed? Where are they inserted and what is
their use? Sever them from their attachment at the keel
and dissect them away. Scrape the flesh carefully from
the large sternum and connected bones. Note a V-shaped
bone, the furculum or wish bone, with the apex attached
to the most ventral and interior part of the keel. This
bone is composed of the two-clavicles grown together at
their sternal ends. The pair of bones attached to the an-
tero-lateral angles of the body of the sternum at their
proximal, and to the shoulder at their distal ends are the
coracoids. Note the ribs attached to the sides of the ster-
num. Remove the sternum very carefully by disarticu-
lating it from the furculum and the coracoids and by cut-
ting the ribs on each side. Inflate the lungs and the air
sacks in the body cavity by blowing into the trachea, How
does the bird breath? Is there any residual air left in the
lung between breaths? The temperature of the blood is
higher in birds and the pulse more rapid than in other ani-
mal forms. From the structure of the breathing apparatus,
would you expect this? Why? Trace the trachea to its
division into bronchi. Near the division on the trachea
note a swelling. This is the syrinx, or voice organ of
birds. Notice the heart and the pericardium. Slit the
latter open. Cut off the posterior end of the heart. Are
the two ventricles separated? Which is the stronger?

What is the shape of each? How many auricles are there?

U a7

78 A MANUAL OF ZOOLOGY

Three veins enter into the right auricle, two precavae and
one postcava. From the right ventricle arises the pulmo-
nary artery which divides near the heart into two branches
which lead directly to the lung. From the lungs the blood
returns to the left auricle by two distinct pulmonary veins.
One large artery, the aorta, comes off from the left ven-
tricle. Inflate it through the left ventricle with the blow
pipe and trace it out as far as possible. Demonstrate
these points and also the valves between the auricles and
the ventricles. Trace the digestive system from the mouth

, through the oesophagus, the crop, the oeSophagus, the

proventriculus or fore-stomach, the muscular stomach or
gizzard, the duodenum, the small intestine, the large intes-
tine, to the cloaca. The muscular stomach is the most
noticeable part of the system. The expansion of the
oesophagus leading into it is the proventriculus. The loop
posterior to the gizzard, holding between its folds the long
light-colored pancreas, is the duodenum. About an inch
from the cloacal end of the intestine are found two little ~
bud-like diverticula which mark the junction between the
large and the small intestine. Emptying into the cloaca
from the dorsal side, is a bag-like diverticulum, the bursa
fabricii of unknown function. Cut the alimentary canal
open longitudinally and note differences in the mucous
membrane. Note the contents of the gizzard, the muscu-
lar structure of the mucosa, and the teeth. Above and
overlapping the sides of the gizzard is the liver. How
many lobes has it? Is there a gall bladder? Beneath the
gizzard find the spleen. Sketch the digestive system dia-
grammatically. Dissect out the lungs. Note how they
are related to the ribs. In the dorsal-posterior part of the
body lie the lobulated, brownish kidneys. How many
lobes have they? How are they related to the skeleton?
Ventral to these in the male lie the two round, light-col-
ored testes connected to the cloaca by the two vas defer-
ens. In the female, in place of the testes lies the ovary.
Leading back to the cloaca find on the left side a single
oviduct. How does this compare with the turtle? The
oviduct secretes the white of the egg, the enveloping mem-
brane, and the shell. Trace the ureters from. the kidneys

to the cloaca. Make a diagram of the urinary and the
‘ ’

A MANUAL OF ZOOLOGY 79

generative systems. Dissect away the lower jaw by break-
ing it down and cutting carefully. Note the ball and
socket articulation and the openings into the larynx and
the oesophagus. How does the tongue compare with the
tongue in the other forms? Pass a bristle into the nostril
and notice where it enters the mouth. Note the median
fissure in the roof of the mouth and the little papillae
fringing its édge. Which way do they slant? What is
their use? Dissect out the ear noting the outer ear drum
composed of an inpocketing of the skin. Back of this find
the middle ear. Pass a bristle into the lower opening
leading inward from this and find where it leads. By care-
fully breaking away- the bone find the inner ear with its
semicircular canal. Remove the upper mandible by bend-
ing it upward and breaking it off. Dissect out the eye,
noting the four recti, and the two oblique muscles attached
to its surface: Note the cartilaginous ring surrounding
the cornea. Compare this with the turtle. Open the cor-
nea and note in order the aqueous humor, the iris, the
crystaline lens, the vitreous humor, the retina, the choroid,
and the sclerotica. Make a sketch of the front and also
one of the side view of the lens. Which side is more
convex? Compare its shape with that of each form
studied. Dissect out the brain by picking away the thin
bone covering it. Note the small conical olfactory lobes,
the cerebral hemispheres, the pineal body, the transversely
grooved cerebellum, the round optic lobes, the medulla, the
infundibulum, and the optic chiasma. Note especially the
very large cerebrum. Compare this brain in every point
here named with that of the forms studied before: Make
a sketch of the upper and one of the under surface of the
brain. Dissect away and scrape clean the wing and at-
tached scapula. Make a drawing and name on it the fol-
lowing. parts: scapula, humerus, radius and ulna, carpal
bones, carpo-metacarpus, and phalanges. Dissect away and
scrape clean the bones of the leg. Make a drawing of this
and name the parts; femur, tibia, fibula, tarso-metatarsus,
and the phalanges. How do the tibia and the fibula
compare with those in the forms studied before? Dissect
out some cervical vertebrae and note the method of articu-
lation.

im Ob baiiguiz cia liee: kicnaieitsndadingas ave utgcam nates eee 4
Ascon Sponge....... Hate iseenisedue seimaunemmnimeme mets 7
Gampanularian Hydroid...............5. ccc ce see eee 11
Gattis tantric neat a cate 27
DG BAF ISH cecsecisgiv an acieeanieds aatien ay saene eenawiacead 36
PEO ON hase es eercronrcsts ada etsidarer aaa Galea 14
English Sparrow. .........0...00cceceseseeeeeeees cau 5
Eb pao irl cheapie is anmeceeplanebel 48
Gra tte cannes cease sasaeataca canteens ees 9
Piydritcanakianncaacce sect Abaieitineaam genomes 10
EGbBliiixyaseancademumuanidad shaded GamMEoAlane bows 18
NGOS tice accrasssevarits wich ie teaseoneauiare haarh ech tdbetnetonep inane crate 24
Paramoecium ..........0000cccccce cece ceueeeneeeeeeeee 5
Perch invesnnessratttcetacieys een apace stone ince eer awa anion 42
Squid: eS gaincechieatenesioeiatwloustins Sees sie eis 29
Starfish....... OL ilth cinerea ces dcaadan ea Sree 12
Toilet Sponge. .......... cc cece cc cce ccc cenneeeseecennes 9
Pile ie hoctaakal alm uduliteecen dace chekecsasteaseanentea atone 69