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BIOLOGY

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BIOLOGICAL ATLAS

A GUIDE TO THE PRACTICAL STUDY OF PLANTS

AND ANIMALS

Stoapteu to tfje requirements of tije ILonion SJnifoersitg, Science antJ Slrt
Department, ano for use in Scfjools ant (Colleges

WITH ACCOMPANYING TEXT

COXTAIXINC;

ARRANGEMENT AND EXPLANATION, EQUIVALENT TERMS, GLOSSARY

AND CLASSIFICATION

423 COLOURED FIGURES AND DIAGRAMS

D. M'ALPINE, F.C.S.
\

LECTURER ON BIOLOGY AND BOTANY, EDINBUKOH, AND HONOURMAN OF THE SCIENCE AND ART DEPARTMENT;
AUTHOR OF "sllOKT NOTES FOR BIOLOGICAL STUDENTS," AND "A ZOOLOGICAL ATLAS "

AXD

A. N. M'ALPINE, B.Sc. (Honours) LOND.

LECTURER ON BOTANY, SCHOOL OF MEDICINE, EDINBURGH ; PROFESSOR OF BOTANY AND NATURAL HISTORY, NEW VETERINARY
COLLEGE, EDINBURGH, AND ASSOCIATE OF THE ROYAL COLLEGE OF SCIENCE FOR IRELAND

Fl FTH THOUSAND

W. & A. K. JOHNSTON

EDINBUEGH AND LONDON

MDCCCLXXXI

^ °

Q//3/7

BIOLOGY
UBRAPv

G

PREFACE.

IT is now generally recognised that a certain acquaintance with actual specimens is necessary for
the proper understanding of Plants and Animals. By the practical study of representative forms,
exemplifying the leading modifications of plant and animal life, the student obtains a basis of
distinctly observed fact with which to compare other forms, and round which to cluster the infor
mation derived from books.

The University of London has given practical shape to this idea by selecting a series of common
types which " each candidate must be prepared to examine microscopically, to dissect and to describe."

In this Atlas, which is intended to serve as a guide to, and not as a substitute for, practical
work, drawings are given of the various points of importance exemplified by each of these types,
to enable the student to make out the points for himself on the actual specimens. Experience
both as students and teachers has taught us, that in this constant appeal to the object itself, the
student is greatly assisted by clear and accurate drawings. In the triple alliance, as it may be called,
of description, drawing, and object, is found the easiest, safest, and surest means of successful study.

Not only is the Atlas a guide to practical work, but since it contains the results of that work
iii a permanent form, a glance at the drawings with their accompanying description will serve as a
valuable refresher to the memory before going up for examination.

Further, the Atlas may be used with any of the Text-books of Zoology or Botany in common
use, such as those of Huxley, Nicholson, Macalister, Sachs, M'Nab, etc., because equivalent terms
are noted in the text, and thus the language of the science is translated as it were into the different
dialects.

The drawings belonging to each form represent the leading features in the history of its life.
The structure as a whole is first shown, then the details of the various parts by means of separate
drawings, and finally so much of the history of its development as is likely to be required.

In every case the types represented have been practically examined, and drawings made from
nature. A number of the drawings are taken from dissections and microscopic preparations made
in the Biological Laboratory of the Eoyal School of Mines, London. Others are copied from reliable
sources whenever they give clearly and correctly the most instructive view of the object. In the
development special care has been taken to give only such representations as were drawn by
practised observers, e.y. the development of the Arnreba is taken from Haeckel, and that of the Cray
fish from Eathke.

Drawings after nature are headed Figures, and Diagrams are occasionally introduced for
explanatory purposes.

The explanatory text arranges the information obtained from the drawing in a convenient form,
cxplaiiis briefly the nature of the object seen, states equivalent terms when the same thing is
differently named by standard authors, gives the derivation of names when that throws light on their
meaning, and accents them where there is any danger of wrong pronunciation, and finally sums up
the distinctive characters in the form of a classification.

324887

iv PREFACE.

A few general practical directions are given to enable the student to adopt those expedients in
the examination of specimens which experience has shown to be the best. These instructions are
necessarily brief, but a detailed account is less necessary since the methods to be pursued are given
clearly and at length in Huxley and Martin's Elementary Biology, to which the student is referred.
The following features of the Atlas may be specially mentioned : —
The names of the various parts are placed on the drawing.
The description faces the Plate.
Colour is used to distinguish the different organs, and as a rule, corresponding parts have

the same colour throughout in order to render comparison easy.
The size of a microscopic object is generally given, or shown by means of squares, to

prevent misconception.

The comparative Histology of Frog and Man shows that a close correspondence exists
between the structure of the Frog and that of higher animals, and thus justifies its
detailed study as a representative form.
The complete life-history is usually given.
Separate drawings are freely used for the different systems of the Plant or Animal body,

and thus all the evils and confusion arising from overcrowding are prevented.
Equivalent terms allow of its being used with any standard text-book.

No apology is needed for issuing a work of this kind. While there are large and well-executed
wall-diagrams which the student may admire at a distance, there is no set of drawings at a convenient
price and in a handy form which he can use as a map to show him the various regions of the Plant
or Animal, and guide him in his attempts to explore them. It is hoped that the cheap and con
venient form of the Atlas may favour its introduction even into higher-class schools. There the
study of Biology might be made a powerful instrument, both of information and training, and a
valuable preliminary to the study of Physiology.

We are much indebted to Mr. S. P. Eastick for valuable aid received while the work was in
progress. No pains have been spared to ensure accuracy, yet doubtless some mistakes have escaped
notice.

EDINBURGH, January 1880.

PREFACE TO THE SECOND EDITION.

THE attempt to encourage practical work in Biology by means of clear figures briefly explained, and
accompanied by instructions for the examination of specimens, has evidently been received with
favour, since a second edition of the " Biological Atlas " has been called for within a year of
publication.

Both Text and Plates have been carefully revised, and such alterations and improvements
made as will tend to render it still more serviceable. However, few changes have been found
necessary.

The colouring of the Animal portion of the work has been somewhat altered, in order to
bring it into harmony with that of the " Zoological Atlas," to which the present work may be
regarded as an introduction.

D. M'A.

EDINBURGH, April 1881.

LIST OF PLATES.

PLANTS

INVERTEBRATE
ANIMALS

VERTEBRATE

ANIMALS

PLATE

I. YEAST AND BACTERIA ....... Facing page 1

II. BROWN MOULD AND GREEN MOULD ...... 3

III. PROTOCOCCUS AND CHARA ....... 5

IV. CHARA (completed) AND BRACKEN FERN ..... 7
V. BRACKEN FERN (completed) ....... P

VI. FLOWERING PLANT . . . . . . . . 11

VII. „ „ (continued) ...... 13

V VIII. ,, „ HISTOLOGY ...... 15

IX. PROTEUS ANIMALCULE AND BELL ANIMALCULE .... 17

X. FRESH-AVATER POLYPE AND EARTH- WORM ..... 19

XI. EARTH- AVoRM (completed) ....... 21

XII. LOBSTER AND CRAYFISH ....... 23

XIII. „ „ (continued) ...... 25

XIA~. ., „ (continued) ...... 27

XV. ,, „ (completed) ...... 29

XVI. FRESH-AATATER MUSSEL ....... 31

\ XVII. SNAIL 33

XVIII. FROG — EXTERNAL CHARACTERS AND GENERAL ARRANGEMENT OF INTERNAL

ORGANS .....'.. 35

XIX. „ SKELETON 37

XX. „ CIRCULATION AND RESPIRATION ..... 39

XXI. ,, NERVOUS AND MUSCULAR SYSTEMS . .... 41

XXII. .. SENSE-ORGANS, RENAL AND REPRODUCTIVE ORGANS, AND TADPOLE 45

XXIII. .. DEVELOPMENT AND COMPARATIVE HISTOLOGY . . 47

\ XXIA7. COMPARATIVE HISTOLOGY OF FROG AND MAN ... 49

GENERAL DIRECTIONS FOR PRACTICAL WORK.

FOR the examination and dissection of the various specimens the following apparatus will be required : —

Detecting Instruments. — Sharp knife or scalpel; forceps; dissecting needles; scissors; and dissecting
dish.

Dissecting needles may be readily made by fastening ordinary needles in penholders. To fasten the
needle, hold it in a pair of pliers and push the sharp end into the wood ; withdraw the needle again and insert
the blunt end. These needles may be made to cut by grinding edges on them. The needle is readily bent by
heating in a gas flame and bending with the pliers. Such needles are very useful in dissecting flowers.

Dissecting Dish. — A shallow vessel may be used, with a plate of wax, gutta-percha, or black paraffin
(prepared by melting down solid paraffin and lampblack) covering the bottom, on which to cut up or pin down
the specimen. A tight-fitting lid with a layer of cork fastened to the inside can be used as a dissecting board.

Optical Instruments. — Microscope; pocket lens, which may be used also as a dissecting microscope by
having a fixed rod on which it can be moved up or down, leaving the hands free for teasing, etc. ; watch
maker's niagnifying-glass, which may be used in dissecting out nerves, blood-vessels, or any minute structures.

Small apertures are best made out by taking a glass tube drawn out to a fine point and blowing through
it to enlarge the opening. Bristles can then be readily inserted.

Reagents, etc. — Distilled water; weak spirit; solutions of magenta, carmine, iodine, salt, potash, and
chromic acid ; glycerine ; acetic acid.

A weak solution of bichromate of potash may be used instead of spirit for preserving.

A good plan for dropping reagents is to fix glass rods in the corks of the bottles.

YEAST.

Mounting. — Get some Yeast at the brewer's or the baker's, and place a small drop on a glass slide. Cover
with a cover-glass for examination under a high power of the microscope.

Staining. — Place a little of the staining solution beside the cover-glass, and arrange a slip of blotting-
paper at the opposite side, so as to cause a current of the staining material.

Crushing. — By gentle pressure of the finger or some blunt instrument the wall will burst and the contents

flow out. To prevent breaking and dimming of the cover-class it is protected by a tiny pad of blotting-paper,
i

BACTERIA.

Mince some lean meat and soak in cold water for an hour ; filter, and keep in a warm place for several
days ; examine the liquid and the scum which forms on the surface with the highest power of the microscope.

MOULDS.

Teasing. — Take a very small portion of the mould and lay it on a slide with a little water, then tease out
by means of two dissecting needles.

PROTOCOCCUS.

Mounting. — Take a bit of the bark of any tree with green scum upon it, brush off the Frotococci and
mount in water.

Mount a drop of water from a water-butt containing Protococci, stain with iodine, which kills the
Protococci and renders the cilia visible.

CHARA.

Hardening. — A weak solution of chromic acid is used. The chromic acid, in addition to its hardening
action, acts also as a solvent, dissolving any limy incrustation.

Embedding the slender Stem. — Soak a piece with gum, which will fill up any cavities ; then harden the gum
by dipping in alcohol, which removes water, leaving the stem surrounded by a coat of hardened gum. Place a

little bit thus prepared in a hole scooped out in solid paraffin. Melt a little paraffin in a small spoon and pour
around the specimen.

Section-cutting. — Wet razor with alcohol by means of a brush. Cut a number of slices and transfer
them with the brush to a watch-glass. Add water, the gum dissolves, and the sections become detached from
the paraffin.

PERN.

Sections. — The rhizome cuts better after steeping for some time.

Staining. — A transverse section of fibro-vascular bundle, for instance, consisting of hard and close-set
cells, may be stained by soaking with magenta for some time in a watch-glass, then washing with water from a
pipette before mounting.

FLOWERING PLANT.

Leaf. — Cut a small piece out of blade of leaf. Dip it into gum and then into alcohol. Imbed in paraffin
and cut transverse sections.

Peel off a small bit of epidermis from the lower surface, say, of a geranium leaf, and examine in water.

Anther. — Take anther from a flower befpre it opens. Dip in gum and alcohol before imbedding aiid
cutting sections.

Ovule. — One of the Speedwells may be used, e.g. Buxbaum's Speedwell. Dissect out ovules from ovary of
flower from which corolla has just fallen, then tease them asunder under dissecting microscope in a drop of
potash solution and add a little glycerine when mounting.

Embryo. — The common Shepherd's Purse may be used. Dissect out the mature ovules or seeds from
fruit. Commence with youngest fruit nearest the top, afterwards going to older, to get different stages. Mount
in potash solution, press gently with cover-glass, and the embryo will be forced out through the micropyle.

Seeds. — Beans or Peas are readily examined after steeping for a night in water.

Germination. — Wheat and Indian Corn can be readily germinated by placing in moist tow, surrounded by
flannel, and kept in a warm place. The root hairs and root cap can be readily seen on these young roots.

AMCBBA.

Examination. — The readiest place to find some form or other of Amccba is in the slimy matter taken from
decaying leaves in stagnant water. Mount in a drop of water and examine like Yeast.

COLOURLESS BLOOD-CORPUSCLES.

Examination. — Lay a drop of your own blood on a slide, then cover quickly with cover-glass. By means
of a camel-hair brush surround with oil to prevent evaporation.

VORTICELLA.

Examination. — On minute Water-plants, such as Duck-weed, groups are usually found. The operation of
feeding may be observed by introducing particles of indigo or carmine into the water.

HYDRA.

Examination. — Found in stagnant pools and ditches. To examine alive, mount in plenty of water under
a large cover-glass.

Sections. — Kill by adding boiling water. Harden, prepare, and imbed as in Chara.
Sea-anemones treated in the same way might be used instead.

EARTH-WORM.

Dissection. — Kill with vapour of chloroform by placing in a stoppered bottle, with a few drops of chloro
form. It then becomes stretched, and may be dissected under spirit. Fasten out in a dissecting dish, and
with a fine pair of scissors slit it up longitudinally a little to one side of the middle line and pin out the two
flaps. Keedles with borax beads for heads are best for pinning out.

FRESH-WATER MUSSEL.

Dissection. —Cut through adductor muscles of one side and remove the valve. Note the beating of the
heart. Kill with hot water. Harden in spirit before following the course of the alimentary canal

LOBSTER OR CRAYFISH.

Dissection. — Keniove lateral portion of carapace by passing a knife under its free edge from the posterior
end to cervical suture. This part of the carapace is the gill-cover or branchio'stegite (Gr. stego, I cover).
Notice scaphognathite working. Turn out the gills with the knife. Dissect from the left side, as in PL XIII.
figs. 2 and 3.

Place another specimen under water in dissecting dish and it soon dies. Eemove dorsal portion of
carapace and of abdominal somites with scissors, in order to make out the chief organs, as in PL XIII. fig. 1.

Preparation of Skeleton. — Boil in strong potash solution, which dissolves everything but the chitin or
horny substance composing the shulL The parts of the exoskeleton may be disarticulated and laid out in their
natural order.

SNAIL.

The Edible Snail is the largest of all the Snails, hence its convenience for study ; but the Common Snail
may be taken. Snails can be kept alive for a considerable time, and warm water generally makes them
protrude from their shell. Boiling water kills them.

Dissection. — Remove shell bit by bit with strong forceps, and pin the animal out in spirit, dissecting from
the dorsal surface. Lay open pulmonary chamber, then expose the viscera by laying open the dorsal integu
ment of foot along middle line and removing the mantle. The viscera may next be laid out to display them to
advantage.

FROG.

The Edible Frog is chosen on account of its larger size, but the Common Frog will also show the
various points. Kill with chloroform.

Dissection. — A dissection from the ventral surface may be made under water in the dissecting dish by
cutting through the skin in the middle line from the syrnphysis of lower jaw to symphysis of pubis ; then pin
out the skin on both sides, and various muscles, veins, etc., are brought into view. Next open abdomen a little
to one side of anterior abdominal vein, cut through shoulder-girdle, and remove its central portion. The
various viscera are then seen as in PI. XVIII. fig. 2.

Turn over viscera to right side, cut away parts mentioned in PI. XVIII. fig. 3 (text), and pin out with left
side upwards so as to get the sectional view.

Prepare a specimen in spirit and nitric acid for the dissection of the nervous system. Dissect from dorsal
surface, and remove the dorsal wall of the cerebro-spinal cavity by nipping it away with scissors, beginning
at the junction of the skull and spinal column. Dissect out cranial nerves and the nerves of the limbs for
a short distance. Eemove brain and spinal cord and preserve in spirit for future use.

Take a similarly prepared specimen and dissect from ventral surface. Eemove the bodies of the vertebras
and the floor of the skull. Along each side of the spinal column dissect out the sympathetic system, and trace
its connection •with the cranial and spinal nerves as in PL XX. diag. 1.

The principal cranial nerves may be dissected from the left side, as in PL XXI. fig. 5, after distending the
gullet with a piece of glass tubing. Place in chromic acid, with a little nitric acid to hasten the softening of
the bone and the hardening of the nerves.

Section of Spinal GorJ.— Take a piece hardened in spirit, prepare and imbed in paraffin as before, and
mount transverse sections in glycerine.

Circulation in Web. — In a thin piece of wood or cork make a notch to fit the web between two of the toes.
Stretch the web over the notch by thread attached to the ends of the two toes. Keep the skin moist with wet
blotting-paper, and after placing a small drop of water on the web, cover with triangular cover-glass for exam
ination under high power.

Preparation of Skeleton. — After cleaning the bones roughly, steep for about a week in sufficient water to
cover them, then place them for a few days in fresh water, which should be frequently renewed. They may be
cleaned with a brush and then laid out in the sun to bleach. Any grease may be extracted from the bones by
benzol

YEAST PLANT (SACCHAROMYCES CEREVISI/E).

PLATE I.

Vail-

Fig.E

Yta*t CflL mth- ffusl

FiJ. 3.

CM with. OU Sud * Tm.

Fig. 4-

Colony of CtMf

Fig. 5.
Formation o

Walt, t'l' parent i

Fig. 8.

Fig. I.

o 8

83

Fib. ^

VUn-ia

Air

(o. jvy

Diagram 1 .
o

PHYSIOLOGY OF YEAST

Water i O.H.!
/C. O. ff./

Calcium,

. O. j
{Co- T. O.I

Add-

/C. 0.1

0000 00000
o o o o o o o
o o o o o o o
oo o o o o o o
oooooooo

BACTERIA

Fift.2.

Fie. 3.

Water

-Alcohol 1 C. O. IT. I
Glycerine { C- O. H. /

ii^h i-LouJon

PLATE I.

THE YEAST PLANT.

Fio. 1. Showing —

/ Cell-wall or sac.
A CELT, J Protoplasm (Gr. protos, first; plasma, from plasso, to mould).

( Vacuolo filled with cell-sap (L. vacuum, an empty space).
FIGS. 2, 3, ami 4. Showing —

MULTIPLICATION BY BUDDING OB GEMMATION (L. gemma, a bud).

The commencement of the process is seen in fig. 2. A bit of protoplasm is pushed out,
stretching the cell-wall and making it thin. Fig. 4 shows a cell aggregate or colony produced
by a repetition of the process of budding.
Fio. 5. Showing —

MULTIPLICATION BY ENDOGENOUS DIVISION (Gr. emlon, within; gennao, I produce).

The protoplasm collects usually into four round masses, each of which takes on a cell-wall.
Culls produced in that way are called Ascospores (Gr. asJcos, a bag; sporu, a seed) or Endo-
conidia (Gr. endon, within; Iconis, dust).
Fia. 6. Showing —

AS'COSFORES set free by rupture of the cell-wall of parent, and multiplying by gemination.
Fio. 7. Effect of—

Magenta — Stains protoplasm, leaving cell-wall comparatively unstained.

Crushing — Euptures the cell-wall, and shows that the cell-wall is tough and resisting, while the

protoplasm is semi-fluid.

Potash (KHO) — Dissolves out the protoplasm.
Iodine — Stains protoplasm.
Fio. 8. Measurement by eyepiece micrometer.

DIAGRAM I. PHYSIOLOGY—

a. Shows the composition of a fluid fit to nourish yeast (Pasteur's fluid).
Elements which make cell-wall (C.O.H.).
Elements which make protoplasm (C.O.H.N.).
Elements which make ash (P.S.K.Mg.Ca.).

I. Shows the composition of the fluid when acted upon by yeast. Process of fermentation
(ferveo, I boil).

/ Carbonic acid (C02).
Sugar becomes -> Alcohol.

( Small quantities of succinic acid and glycerine.
About two per cent, of sugar is unaccounted for.
Ammonium tartrate, etc., used up by the yeast.

,,, , , f Manufacture of alcohol and carbonic acid,

lotal result . {

[ Manufacture of cell-wall and protoplasm.

CLASSIFICATION OF YEAST.

Kingdom — Plantae, because it possesses a cell-wall made of cellulose, and can manufacture

protoplasm.

Bub-Kingdom — Thallophyta, because it possesses neither root, stem, nor leaf.
Class — Protophyta, because it has no sexual process of multiplication (Gr. prolos, first; plnjton,

plant).

A

Group — Fungi, because it possesses no green colouring matter.

Order — Saccharomycetes (Gr. saJccJiaron, sugar; muJces, a fungus), because it requires a saccharine

liquid for nourishment.
Genns — Saccharomy'ces.
Common Name — Yeast or Torula.

BACTERIA.

FIG. 1. MICROCOCCI — Spherical (Or. mikros, small; koI.-Jcux, a berry), seen singly and togetlier.

FIG. 2. BACTERIA — Cylindrical (Gr. baJtteriou, a staff).

FIG. 3. BACIL'LI — Filiform and straight (L. lacillum, a little staff).

FIG. 4. VLBRIONES — Filiform and curved (L. vibro, I quiver).

FIG. 5. Srmii/LUM — Spirally twisted.

Note the threads of protoplasm at each end, cilia (L. cilinm, an eyelash).

FIG. G. THE ZOOGLOEA — Motionless Bacteria, embedded in gelatinous material (Gr. soon, an animal ; glia,
glue).

CLASSIFICATION OF BACTERIA.

Kingdom — Plants.

Sub-Kingdom — Thallophyta.

Class — Protophyta.

Group — Fungi.

Order — Schizomycetes (Gr. scliisis, a splitting), because they multiply by splitting.

Genera — Micrococcus, Bacterium, etc.

COMMON BROWN MOULD (MUCOR MUCEDO).

PLATE II.

4 Gemrnfi.ituui (\rttidiiun

ir **

isj stage

b .

Fi g 2 TcT-ntimil Cell ctnttauiing Camdia.

COMMON GREEN MOULD

(PENICILLIUM CLAUCUM)

Fig.S.

Fig. 6. tiertnuiutuy

fton EiUnburgfa i

PLATE TI.

COMMON BROWN MOULD.

FIG. 1. THE MUCOE PLANT PRODUCED FROM A CONIDIUM. Showing —

Branched hypha.

Erect hypha (Gr. liyplie, a weaving) terminating in a minute enlargement — the sporangium.
FIG. 2. Showing —

End of erect hypha.

Columella (L. a little column).

Terminal cell, conidia case, or sporangium (Gr. spora, a seed; angeion, a vessel).

Wall of sporangium with crystals of oxalato of lime,

Spores oraendo-conidia (Gr. entlon, within ; Iconis, dust).
FIG. 3. Showing —

Burst conidia-case or sporangium.

Collar, the remains of the wall of sporangium.

Endo-conidia or spores.
FIG. 4. Showing —

The conidium germinating and producing a branched hypha, which ultimately develops into tho

form shown in fig. 1.
FIG. 5. Showing —

Portion of branched hypha with protoplasm removed.

No septa.
FIG. C. Showing —

Portion of old submerged hypha, breaking up into distinct joints — the Chlamydospores (Gr.
chlamys, a coat ; spora, a seed) or Mucor-torulse, each containing a vacuole.

Note. — Vacuolated protoplasm and septum.
FIG. 7. THE SEXUAL PROCESS —

a fy b. Two distinct processes given off from the hyphse.

c. Terminal cell separated off from each process.

d. Union of the two terminal cells to form a zygospore (Gr. zugos, a yoke ; spora, a seed). Since

the uniting elements closely resemble one another the process is called conjugation.

.DIAGRAM OP THE PRO-EMBRYO OF Muuou PRODUCED FKOM A ZYUOSPORE. Showing —
Zygospore.
Unbranched hypha.
Erect hypha.
Conidia-case or sporangium, containing conidia, each of which can produce the Mucor plant

(%• 1).

CLASSIFICATION OF MUCOR.

Kingdom

Sub-Kingdom — Thallophyta.

Class — Zygosporcaj, marked by its sexual process, viz. conjugation.

Group — Fungi.

Order — Zygomycetes.

Gemts — Mucor.

Common Name — P.rown Mould.

COMMON GREEN MOULD.

FIG. 1. Showing —

Dichotomously branched hyplia (Gr. dichotomia, a division into two parts) subdivided by scuta.

Granular vacuolated protoplasm in the cells.

Aerial hypha, branching at its ends like a brush or pencil, hence the name Penicillium.

The terminal branches, corresponding to the hairs of the brush, breaking up into stylo-conidia

(Gr. stulos, a stalk ; konis, dust).
FIG. 2. THK CONIDIA. Showing —

Size — ^ inch in diameter.
Form — Spherical.

< Wall.
Structure — -s Protoplasm.

(. Vacuole.
Germination —

a $ b. Eminence formed at one point of the conidium.

c. Eminences formed at two points.

d, e, fy f. Elongation and subdivision of the eminences by septa.

Note. — The ultimate result of the growth of the conidium is to produce a Feiiicilliuin like that in fig. 1.

FIG. 3. Showing the SEXUAL PROCESS —

This has quite recently been made out, and occurs under peculiar conditions, as yet attained
only by artificial means. The male element or antheridium (Gr. anthos, a flower ; ciJoa, form)
is a short branch of a hypha, the female element or carpogonium (Gr. carpos, fruit ; gone, seeify
also a short branch coiled like a cork-screw. These two elements come together and exercise on
one another some reciprocal influence. A sexual process of this kind, where the conjugating
elements are different, is called Fertilization. As the result of fertilization a fruit or sporocarp
is produced, like a little pin-head. That fruit consists of an outer mass of sterile hypha;
enclosing a mass of fertile hypha?. These fertile hyphse are developed from the female element.

FIG. 4. SECTION OF SPOROCARP (Gr. spora, a seed; carpos, fruit) or FRUIT — •
Sterile tissue.
Fertile tissue in centre (red).

FIG. 5. PORTION OF FERTILE TISSUE REMOVED FROM SPOROCARP. Showing —

a. Asci or cells containing spores (Gr. askos, a bag).

b. An ascospore removed from an ascus.
FIG. 6. Showing GERMINATION OF ASCOSPORE.

CLASSIFICATION OF PENICILLIUM.

Kingdom — Planta;.

Sub-Kingdom — Thallophyta.

Class — Carposporea?, because it possesses a sporocarp.

Group — Fungi.

Order-- Ascomycetes, because of the asci.

Genus — Penicillium (L. penieillum, a painter's brush).

Common Name — Green Mould.

PROTOCOCCUS VULGARIS.

PLATE III.

Fi$ I- .Resting form

Fig. 2 Efliet. of nagau*

1 Resting form*

Protococcus Pluvialls
Fig. 2 B£,nJ)m*L<m ObrJjiriMon.

b. I'u2tts Tvcpt in- tbcric.
' ' Water -rnOl.

D lag ram oT Physiology
-Arrangement

Erernosphaera Viridis

M&~^

~^:^-n\ {•'&• '• :'&*-

•;&&&• i^ >.-*VM

ip^1^'-- *

^'LV ~about, fSo of an Inch in din

L ayer of chlorophyll
i ^EnJier layer

Diagram 1.- Facfnation of Cortex

ceU

cell

3todal> Cells

fauna Jtea/'

« fcA.K.J»hn«ton. Edmlroith kLu

PLATE IIL

PROTOCOCCUS.

PROTOCOCCUS VULGAEIS, the green scum on the bark of trees (Gr. protos, first ; Icoltltos, a berry).
Fio. 1. Showing —

f Cell-wall or sac.
A CELL •< Protoplasm containing green, sometimes red, chlorophyll (Gr. chloros, green ; phyllvn, a

( leaf).
Fio. 2. EFFECT OK —

«. Iodine — Protoplasm stained and nucleus brought out.

b. Iodine and sulphuric acid — The cell-wall becomes blue and the protoplasm coagulates. The

sulphuric acid converts cellulose into starch, and the iodine with starch forms the blue iodide
of starch.

c. Crushing causes rupture, and shows that the cell-wall is tough and resisting, while the proto

plasmic contents are semi-fluid.

d. Potash (KIIO) dissolves out the protoplasmic contents.
FJG. 3. Showing MULTIPLICATION BY DIVISION —

a. Division into two.

b. Division into four.

This process is the same as that which goes on at the growing point in the higher plants

(See Chara, fig. 4.)
Fio. 4. Showing MULTIPLICATION BY ENDOGENOUS DIVISION AND PRODUCTION OF MOTILE FORMS —

a. The protoplasm has gathered itself up into a number of round masses, each of which is a

zoospore or zoogonidium (Gr. zoos, alive ; gone, seed).

I. A zoospore that has escaped from the parent cell. It consists of a naked mass of protoplasm,
with two long vibratilo protoplasmic threads or cilia by which it moves about.

PROTOCOCCUS PLUVIALIS, found in water-butts (L. pluvia, rain).

( Cell-wall.
Fio. 1. RESTING FORM -J Protoplasm.

[ Chlorophyll grains.
FIG. 2. PREPARATION FOR DIVISION.
FIG. 3. Showing RESULT OF DIVISION.
FIG. 4. MOTILE FORMS — ZOOSPORES OR ZOOGONIDIA—

u. The protoplasm has drawn itself away from the cell-wall at all but two points. At these

points two vibratile cilia protrude through the cell-wall.
1>. A naked zoospore.
FIG. 5. EREMOSPHA:RA VIRIDIS, a close ally of Protococcus, containing starch granules —

a. Unstained.

b. Stained with iodine to bring out the starch granules.

No starch is found in the Protococcus itself, probabl.y because it uses up the starch as fast
as it is manufactured.

DIAGRAM OF PHYSIOLOGY — •

« # b. Show that in the dark no oxygon is evolved from carbonic acid (C02).

a # o. Show that in the light the carbonic acid is absorbed and oxygen gas given off.

This process, viz. the absorption of COa and evolution of 0, is called Assimilation.
Respiration is quite a different process ; it consists in the absorption of O and the evolution of
COj. lu the green plant these two processes go on together.

CLASSIFICATION OF PROTOCOCCUS.

Kingdom — Plantie, because it possesses a cellulose wall, absorbs C02 and evolves 0.
Sub-Kingdom — Thallophyta.
Group — AlgiB.

CHARA.

FIG. 1 (a). Showing —

. f Nodes (L. nodus, a knot).

( Inteinodes (L. inter, between).

. [ Leaves arranged in whorls.

APPENDAGES <

( Branches.

I Nodes.

BRANCH . . < Internodes.
( Appendages.
Nodes with their leaves.

TERMINAL BUD •, „,

Short internodes.

FIG. 1 (l>). Showing the CORTICAL LAYEE INVESTING THE INTERNODAL CELL (L. cortex, Lark).
FIG. 2. TRANSVERSE SECTION OP INTERNODE. Showing —

Cortex.

Wall of internodal cell

Protoplasm lining the wall, the so-called primordial utricle (L. primordim, original ; utrifiilin,
a little bag).

Chlorophyll granules arranged so as to leave an uucoloured portion, the neutral lino.

Inner layer of protoplasm — the moving layer.

Vacuole, filled with cell-sap.
FIG. 3. Showing the NODE —

A surface of cells one layer thick.
FIG. 4. THE TERMINAL BUD DISSECTED TO LAY BARE THE GROWING POINT. Showing —

The hemispherical apical cell. It grows in length and multiplies by division transverse to the axis.

The cell immediately beneath apical cell afterwards divides transversely into two portions — the
lower an internode, the upper a node.

The internodal cell (blue). It elongates, but does not divide at all.

The nodal cell (uncoloured). It does not elongate, but divides parallel to the axis, so as to form
a transverse partition of cells.

Nodal cell originating a young leaf.

Nodal cell originating the cortex.
FIG. 5. PORTION OF LEAP. Showing —

The uncovered apical or terminal cell.

Nodal cell.

„ . f Descending lobes.
Cortex \ °

[ Ascending lobes.

FIG. 6. MOVEMENTS OP THE PROTOPLASM —

The arrows represent the direction of the currents of protoplasm.
The uncoloured bands are the neutral lines (see fig. 2).

DIAGRAM I. Showing FORMATION OP CORTEX.

The peripheral cells of the node (shown in fig. 3) send pockets upwards and downwards to
form the ascending and descending cortical lobes.

PLATE IV.

Fig. 3 . $tritfture. of Carpotjonuun
/. t/uzra/ 1}

i£ 5. Germinating Carpoyoruiuti
fining

THE BRACKEN FERN [PTER1S AQUIUNA

W ttA K Jo'nnaton.Sdinbiirfh & London

PLATE IV.

- continued.

Yin. 1. PORTION OF LEAF. Showing —

Antheridium, male organ, or globule.

Carpogonium, female organ, nucule, sporangium, or spore- fruit (Or. itpora, r\ seed; angeion, a

vessel).

FIG. 2. THE ANTHKIUDIUM DISSECTED. Showing —
a. Shield.

Manu'brium (L. a handle).

Capitulum (L. a little head) (blue).

Secondary capitula (blue). Not named on drawing.

Filaments.

1>. Portion of filament, with a spermatozoid in each of its cells.
c. A liberated spermatozoid, with two long cilia.
Fio. 3. THE CARPOGONIUM on NUCULE —

Central cell.

Twisted filaments, quite different from the filaments of the antheridium.

The one-celled corona in Chara, and the two-celled corona in Nitellu.
FIG. 4. DEVELOPMENT OF THE CARPOGONIUM OR SPORE-FRUIT. Sectional view.
Fio. 5 and DIAGRAM I. Showing DEVELOPMENT OF THE SPORE, enclosed in sporocarp —

Proembryo.

Pseudo- whorl of leaves, with the Chara in its axil.

CLASSIFICATION OF CHARACE^L

Kingdom — Plantiu.

Sab-Kingdom — Thallophyta (exceptional in having axis and appendages).

Class — Carposporeoe, because it has a spore fruit.

Group — Algae.

Order — Cliaracea?.

Genera — Chara and Nitella.

THE BRACKEN FERN.

FIG. 1. Showing—

( Rudimentary leaf.

T „, ng leaf.

J_,LA\LS <

J Cut leaf.

( Old leaf.

Underground stem or rhizome (Gr. rliiza, a root; onws, the same as) with its growing point.
Hoots.

FIG. 2. LATERAL LINES OF RHIZOME.
FIG. 3. Showing —

( Eachis (Gr. rachin, a spine, ridge).

a. PART or LEAF OR FROND . . . . < Pinna (L. a feather).

( Pinnule (L. pinnula, a little feather).

b. TWO PINNULES VIEWED FROM BELOW ( J?dU8i™ <L' '"^ *° Cl°^ C°Vf ^

( Sorus (Gr. soros, a heap), a cluster of spore-cases.
FIG. 4. Showing FORKED VENATION AND INDUSIUM.
FIG. 5. SPORE-CASE OR SPORANGIUM. Showing —

Stalk.

Case.

Annulus (L. a ring). In e, a small part below the spores is inadvertently uncolourcd.

Spores.
FIG. G. SPORE. Showing —

Exosporium (Gr. exo, outside ; spora, a seed).

Endosporium (Gr. endon, within; spora, a seed).

Protoplasm with oil-globules.

Nucleus.
FIG. 7. DEVELOPMENT OF SPORE. Showing —

a. Endosporium protruded.

b. Divided to form a young prothallus, with root-hairs.

c. Old prothallus with root-hairs, male organs or antheridia, and female organs or archegonia

(Gr. arclios, chief; gone, seed).
FIG. 8. PROTHALLUS UNDER IIIGH POWER. Showing —

r Cell-wall.

CELLS . J prot°Plasm-

' | Chlorophyll granules.

^ Large vacuoles filled with cell-sap.

FERK

PLATE V.

Fig. 2. sfrcJietjonut/ti of Royal, fern

i6. 7. 7>w/M & hortifi Jtftit m i>/'<i, mrtitHt vT A0 J&ttxtmtt under lim power

ol ' hbn> laffti/ar Hu milt undtrhiyh pow'ti- t>. Limymuiuutl

9 Obtii/ite Aetian vt'.tttilk vt'Lraf

Wood-

PLATE V.

FBR.N — continued.

FIG. 1. THE ANTHERIDIUM AND ANTHEROZOIDS OF THE ROYAL FERN (Osmunda Regalis), under surface ol

prothallus (green).

FIG. 2. THE ARCHEGONIUM WITH ITS CENTRAL CELL OR GERM-CELL.
FIG. 3. DIVISION OP CENTRAL CELL INTO FOUR IN THE BRACKEN.

FIG. 4. CONNECTION OF YOUNG BRACKEN FERN WITH ITS PEOTHALLUS BY MEANS OF THE FOOT.
FIGS. 5, 6. TRANSVERSE AND LONGITUDINAL SECTIONS or THE RHIZOME. Showing —

Se. i. Outer scleren'chyma (Gr. slderos, hard; enehuma, tissue).

G. T. Ground tissue or paren'chyma (Gr. para, together ; enehuma, tissue).

F.- V. 13. Fibro-vascular bundles — outer.

Sc.». Inner sclerencliyma.

G. T. Ground tissue.

F.- V. B. Fibro-vascular bundles — inner.
FIG. 7. TRANSVERSE AND LONGITUDINAL SECTIONS OF RHIZOME. Showing —

Epidermis, sub-epidermis, and parenchyma loaded with starch granules.

Fibro-vascular bundle with scalariform and spiral vessels.

Parenchyma with starch.

Sclerencliyma very thick walled (Gr. skleros, hard).
FIG. 8. PORTION OF FIBRO-VASCULAU BUNDLE. Showing —

Cells of fibro-vascular bundle sheath.

Cells of bast sheath with starch granules.

( Bast fibres or hard bast.

BAST OR PHIAEM •; Bast vessels. ]

( Bast parenchyma or procambium. j
1 Scalariform vessels.

WOOD OR XYLEM < Spiral vessels.

( Wood parenchyma.
Note. — In the complete bundle the bast forms a ring surrounding the wood.

FIG. 9. PART OF AN OBLIQUE SECTION OF A LEAF-STALK. Showing the scalarifonu vessels (L. srala, a ladder^
of the bundle.

CLASSIFICATION OF FERN.

Kingdom — Plante.

Sub-Kingdom — Vascular Cryptogams (Gr. kruptos, hidden ; gamos, a marriage). Vascular,

because they possess fibro-vascular bundles ; cryptogams, because the sexual organs are

hidden on an inconspicuous prothallus.
Class — Filicinse.
Order — Filices.

Genm — Pteris (Gr. pferon, a wing).
Species — Aquilina (L. aquila, an eagle).
Common Name — Bracken Fern.

THE FLOWERING PLANT

PLATE VI.

Diagram I

Tkf Lf#/'\

Fid 2 St&itm of Onion.

W. I A.K Johnston. Edinburgh I L

11

I

PLATE VI.

THE FLOWERING PLANT.

DIAGRAM I. Showing—

„ I Node*, bearing leaves (L. nodus, a knot).

I Internodes, bearing no leaves (L. inter, between ; nodus, a knot).
( Leaf.

APPENDAGES OF STEM < Bud, a shortened stem with crowded leaves.
' Branch, an expanded bud.

f Axillary, in the angle between the leaf and stein (L. axilla, the armpit).
POSITION OF BUDS . < „

( Terminal.

Fio. 1 (a). THE HORSE CHESTNUT. Showing —

Interuodes.

Nodes with leaf-scars.

Two axillary buds.

Terminal bud.
Fa;. 1 (6). THE SAME. Showing the scars left by the falling off of the bud-scales. These scars mark the

commencement of a year's growth.
Fio. 2. BULB OF ONION. Showing —

Stem, short.

Leaves, crowded, and stored with nutriment.

Buds (1) terminal and (2) axillary.

Roots, fibrous.

The peculiarity of the Onion is this : it remains permanently in the bud condition. A

permanent bud of that kind is called a bulb.
Fio. 3. Showing KINDS OF LEAVES —

Scale leaves.

Foliage leaves — the green leaves which manufacture starch (L. folium, the leaf).

Bracts — leaves near flowers (L. bractea, a thin plate).

Floral leaves (L. flos, a flower). (Red.)
FIGS. 4, 5. EXAMPLES OF LEAVES —

Pinnate leaf, with elongated midrib (Pea).

Palmate leaf, with extremely short midrib (Horse Chestnut).

Compound leaf. The incisions extending into the midrib, and subdividing one leaf into a number
of leaflets.

Stipules — appendages originating from the base of leaf-stalk, not from the stem.
FIG. 6. Showing FOLIAGE LEAVES united or connate (L. con, together ; nut us, born).
FIG. 7. FLOWER OF PEA. Showing —

Sepal leaves united below (gamosepalous calyx).

Petal leaves of unequal size (irregular corolla indicated in formula by v).
FIG. 8. Showing GENERAL STRUCTURE OF THE FLOWER —

Calyx (Gr. kalyx, a cup).

Corolla (L. corolla, a little crown).

Stamens or Androecium \ _,.,

Filament (L. fit urn, a thread).
(Gr. aner, male ; oikos, > , , . • • n

. Anther containing pollen-grams,
house) (male organs) /

Pistil or Gyncecium (Gr. \ Ovary containing ovules.

gune, female; oikos, V Style.

house (female organs) ) Stigma (Gr. stigma, a brand).
FIG. 9. PLAN OP PEA FLOWER. Showing —
Calyx— .five sepal leaves united.
Corolla = five petal leaves separate.

Androecium = ten stamen leaves, nine united and one free.
Gynoecium = one carpel leaf.

Formula V Ca. (5), Co. 5, An. (9) + 1 Gn. 1.

THE FLOWERING PLANT (CoNTD)

PIRATE VI I.

Strfam ot' Purtil magnified

.---• Poilertip nuts

Fi^. 3. Tran*vfrtt Jtction. of' Anthfr* of' Tulip
t 'aitral Fibre VuAcuLu- Bundle

Thmi,-a seed wUh ons hail' r,-nwvrd
? Secfyfin' Lit' Almomi
& Pea. lai-d open & Tittn removed
* Tht Bean

•f 77u Ht,oi nidi 7't'o'tti & onf cotfUden Ttrnw
p Fliunulf '' Radicle

Tap rovt with

S: A.K JohmttoiL Edinb-jigh J

PLATE VIL

THE FLOWERING PLANT.

DIAGEAM I. Showing—

EEOEPTACLE OR THALAMUS TO WHICH THE FLORAL LEAVES ABE ATTACHED.

f Calyx, hypogynous or inferior (Gr. liupo, under; gune, the female

T organ).

INSERTIONS OF I<LOUAL ) _ ., ° ' . „ .

\ Corolla, hypogynous or interior.

| Stamens, hypogynous.

^ Ovary, superior or free, containing an erect ovule.
DIAGEAM II. Showing—

f Stigma, for receiving pollen.
PISTIL OR GYNCKCIUM . . •< Style.

(. Ovary, containing one ovule.

IMPREGNATION OF OVULE Pollen-grains attached to stigma and throwing out pollen-tubes,

which make their way down the style, enter the micropyle ot
the ovule, and fertilize the germ-cell in the embryo-sac.

DIAGEAM III. Showing -

f Primine or outer coat (L. primus, first), formed after inner coat.

OVULE -< Secundine or inner coat (L. seeundus, second).

( Nucleus, with a giant cell — the embryo-sac.
f Wall of sac.
EMBRYO-SAC FERTILIZED < Embryo.

( Endosperm.
FIG. 1. Showing the EIPE PISTIL OF PEA —

PERICARP — Eipe wall of ovary, dry and splitting into two valves.
SEED — Eipe ovule.
FIG. 2. Showing SEEDS —

f Testa or seed-skins (L. testa, a shell).

-| Endosperm, the so-called albumen (Gr. endon, within ; uperma, a seed;
(Albuminous Seed) ^ Embry0; with two cotyle'dons, or seed-leaves.

f Testa.

2. ALMOND 1 ••-, , , , , . . ,

.. -< Endosperm absorbed into embryo.

(Exalbummous Seed) ( Embry0) with two cotyle'dons.

3. PEA (Exalbuminous Seed).

( Testa.

4 and 5. BEAN I „ , , , ,

,_ .. . ..< Endosperm absorbed.

(Exalbuminous Seed) 1 -n , .., , , , ,

' V Embryo, with two cotyledons.

f Cotyledons.

EMBRYO v Plumule.

( Eadick.
FIG. 3. ANTHER OF TULIP, showing iibro-vascular bundle in centre corresponding to the midrib of the leaf.

Eight anther-lobe with two pollen-sacs. Left anther-lobe with two pollen-sacs.
DIAGEAM IV. FORMATION OF POLLEN-GKAINS BY ENDOGENOUS DIVISION.
FIG. 4. YOUNG BEAN PLANT, showing —
Axls | Tap-root.

( Stem with terminal bud.
I Eootlets.

APPENDAGES -^ 2 Cotyledons.
V Foliage leaves.

HISTOLOGY OF FLOWERING PLANT

PLATE VIII.

Dilg I Transverse section, of ' yourtq ttem. ofHors

tettiu-rn, t»f Leaf
talk aTHarse; eh^fi nut

Fig. 3. 7Vwi*rvw»«» section, of stern of Rjttts.ii* a

F,g. 7 Tmnmrm xctian of Lffif Bladt, afchfrry Laurel

pacfc&L chl
^.o^-if- - containing ctlle

Fi a . 4 /hrftun f^ l,omjt'

tttetitin.
F&rr> vascular hi

Fig. 8. Cells ofEfiid.y-mis

"K

WiAK JohnstcTi. Edmbui-^h t Londoi

15

PLATE VIII.

HISTOLOGY OF FLOWEKING PLANT.

STBM—

DIAG. 1. TRANSVERSE SECTION of a one-year-old stem of Horse Chestnut —
Pith or medulla in centre.
Fibro-vascular bundles arranged in a ring round the pith —

Wood or xylein, including medullary sheath.

Cambium, a soft cellular layer.

Last or phloem outside the cambium.
Cortex, connected with the pith by the medullary ray&
Epidermis.

Note. — The part of the stem outside the soft cambium is readily removable, and is the separable bailc.

Fio. 1. TRANSVERSE SECTION of same stem under the microscope —
Pith, consisting of parenchyma cells.
Fibro-vascular bundle —
Wood or xylein —

Vessels, large openings.
Wood-cells between the vessels.
Cambium, small thin-walled cells.
Bust or phloem—

Soft portion, made up of thin-walled cells.

Hard portion, or liber layer, made up of round thick-walled cells, the central cavity

being almost obliterated.

Medullary rays, brick-shaped cells between the fibre-vascular bundles.
Cortex, angular cells, parenchyma.
Epidermis, a single layer of squarish cells.
FIG. 2. LONG. SECTION of the Horse Chestnut stem —
Pith-cells.

Fibro vascular bundle —
Wood-
Spiral vessels of medullary sheath, elongated tubes with spirally thickened walls.
Annular vessels, elongated tubes with ringlike thickenings.
Dotted ducts, elongated tubes thickened so as to leave thin places, the dots.
Wood-cells, elongated, and when older with thick walls, and then called woody

fibres or wood prosenchyina.
Cambium, thin-walled cells.
Bast-
Soft bast, elongated thin-walled cells.

Hard bast, thick-walled and elongated cells forming the flexible bast fibrea
Cortex, parenchymatous cells.
Epidermis, a single layer of cells.

FIGS. 3, 4. SECTIONS of stem of Butcher's Broom magnified —
Differences from Horse Chestnut stem —

Fibro-vascular bundles are not arranged in a ring round pith, but scattered irregu
larly.
No cambium and therefore no provision for increase after first year.

16

ROOT —

FIG. 5. LONG. SECTION of root of Bean plant —

f Central fibro- vascular bundle, surrounded lay cortical parenchyma
and epidermis.

ROOT \ Epidermis, one layer thick ; at tip of root split into several layers

forming the root-cap or pileorhiza (L. pileus, a cap ; Gr. rhiza,
L a root).

f Appendages of the root developed endogenously (Gr. endon, within ;
KOOTLETS . . . . -j gennao, I produce), and repeating the structure of the main

(^ root.
LEAP —

FIG. 6. The STALK or PETIOLE of Horse Chestnut leaf —
Repeats the characters of the one-year-old stem.
FIG. 7. The LEAF BLADE or LAMINA of the Cherry Laurel —

C Upper epidermis, colourless, a single layer, with the outer walls
I thickened forming cuticle.

I Lower epidermis, like upper epidermis, but stomata more
L abundant.
GROUND OR CORTICAL J Palisade tissue.

PARENCHYMA . . . { Loose tissue with less chlorophyll.
Fibro-vascular bundles, forming veins.
FIG. 8. EPIDERMIS of HYACINTH —

Stoma, the opening (Gr. stoma, a mouth).
Guard-cells (red), two surrounding each stoma.

CLASSIFICATION OF PEA OR BEAN PLANT.

Sub-Kingdom — Phanerogamia, because the sexual organs are conspicuous (Gr. phaneros, visible

gainos, sexual union).
Class — Dicotyledon —

The young plant has two cotyledons (PI. VII. fig. 4).

The fibro-vascular bundles form a ring round the pith (PL VIII. diag.).

Leaf has reticulated venation.

Flower leaves arranged in fives (PI. VI. fig. 9).
Order — Leguminosse, distinguished by the arrangement of the corolla leaves, and the fruit a pod

or legume.
Genera — Pisum (pea), Vicia (bean).

AMOEBA (PROTEUS ANIMALCULE).

PLATE IX.

Fig. I Amoeba,

een. af^inter~vals of a feiv ttcantle

Fig. 3. Z(/?, - Tiirttrry of Anvoebd-

5. freed/ from Cyst,

a . Mnnu-ul appearance

Fifl. 4. Cokntrless Corpus&es of Siutuuv blood.- average ditL. 2&QO
ft. Treated, _jvtifr acetic a*xd ^ c. Seen ut intervals of a minute

BELL ANIMALCULE ( VORTICELLA)

w fcA R John«UD Edinburgh k L

17

PLATE IX.

PROTEUS ANIMALCULE.

STRUCTURE —

FIG. 1. Kctosarc or outer transparent bonier (Gr. eldos, outside; sarx, flesh).
Endosarc or inner granular portion (Gr. endon, within).
Contractile vesicle or vacuole, a cavity filled with a clear fluid.
Nucleus or endoplast, a roundish solid granular portion of protoplasm.

Pseudopodia (Gr. pseudos, false; pous, podos, a foot), processes of the body constantly changing.
MOVEMENTS —

FIG. 2. Changes of form constantly taking place, hence the name of Proteus Animalcule.

Food-particles.
MULTIPLICATION-
FIG. 3, a. Stationary form surrounded by a structureless case or cyst.

b. Mobile form escaped from cyst.

c. Process of fission taking place.

d. Original amoeba divided into two.
CLASSIFICATION — Structural relations with other animals.

Kingdom — Auimalia, because it depends on pre-formed protoplasm and does not possess a

cellulose cell-wall.
Sub-Kingdom — Protozoa (Gr. proios, first ; zoon, an animal), because it is not differentiated into

cells.
Natural Order — Protoplasta (Gr. plastos, moulded), because it possesses a nucleus and contractile

vesicle.

Genus — Amoeba (Gr. amoibe, change).
Common Name — Proteus Animalcule.

COLOURLESS CORPUSCLES OF HUMAN

BLOOD.

FIG. 4, a. Structure — granular with spherical or irregular outline.

b. Nucleus brought out with dilute acetic acid.

c. Amoeboid movements taking place sluggishly.

18

BELL ANIMALCULE.

STRUCTURE—

iiG. 1. Bell-shaped body with slender stalk for attachment.

I Cuticle, a very thin layer of protoplasm investing the body.
Disc, covering the mouth of bell and fringed with cilia.
Peristome (Gr. peri, around ; stoma, a mouth), the ciliated rim separated from the edge

of the disc by a groove.

Vestibulum (L. an entrance), a depression in the groove where food enters by a
_, / permanent mouth. The undigested matter passes out by a temporary anus (L. a

vent).

GEso'phagus or gullet, leading from vestibule into the soft body-substance.
Food-vacuoles, food-particles enveloped iii water and dropped off from the end of the

gullet.

Contractile vesicle.
\Curved nucleus.
„ f Sheath, a continuation of the cuticle.

1 Axis, the central muscular fibre.

DIAGRAM or THK PAEAMCECIDM OR SLIPPEE ANIMALCULE, A FKEE-SWIMMING INFUSORIAN —
Cuticle and cilia.

Cortical layer with two contractile vesicles.
Body-substance like soft-boiled sago.

Funnel-shaped mouth opening by a short gullet into body-substance.
Anus, merely a temporary opening.
MOVEMENTS —

FIG. 2. The spirally-coiled stalk, the retracted disc, and the curved-in peristome.
FIGS. 3, 4. Encysted forms — stalked and unstalked.
Mu LTIPLICATION —

FIG. 5. Longitudinal fission ; a bell divides lengthways into two, and the detached portion finally

becomes like the original.
REPRODUCTION —

FIG. G. A free-swimming bell fuses with a stalked form, producing a single individual ; this is the
so-called process of conjugation. The attached bell was formerly taken for a bud. (Pos
terior cilia not shown.)
CLASSIFICATION —

is iil>- Kingdom— Protozoa.

Nat'ttral Order — Infusoria, because it possesses an outer layer (ectosarc) provided with cilia and
contractile vesicle or vesicles, and an inner substance (endosarc) with nucleus, and usually
with a mouth leading into it and an anus leading out. They occur in infusions, hence
the name.

Genus — Vorticella, so named from the vortex caused by the moving cilia.
Common Name — Bell Animalcule.

FRESH WATER POLYPE (HYDRA)

PLATE X

Fig. I flvctra,

or Common. Hydra.

Ifiy

. 2 Hydra fo

iffL B\"dryj.

I. Longitudinal Section
f Hydra.

'Tentacles

Fid. 3 CdU oi~ihe Ectoderm.

Q

l^udais..

-Jffouth

NtmaiotystfS-

J^cto dfs~rn
ErLdocLerrn,-

SpeTtnatffxoc

C Segmented avnjn,so-caUed,'eyQ'

K- £Tnbryo cells

Diagram 2. -Development of Hydrozoa

&. Section, ff flanula.

b .Section, of Mo

\Ga~minal spot

EARTH-WORM (LUMBRICUS TERRESTRIS)

Fig Z._ThefiTieen Anterior Segments -Ventral aspect

— Anus

Fig I.

'Mouth

•flpenznq of Vas

•WlA.KJohn*ion. Edinburgh 4 London.

19
PLATE X.

FRESH- WATER POLYPE.

GENERAL CHARACTERS —

FIGS. 1, 2. Foot or hydrorhiza (Gr. rliiza, root) attached to some floating body.
Mouth at free end.
Tentacles or feelers (L. tentare, to feel) surrounding the mouth.

( Testis, the male organ.
Eeproductivo organs j Omy> tho f0male organ

Multiplicatioii by budding or gemmation (iig. 2).
GENERAL STRUCTURE —

DIAG. 1. Ectoderm (Gr. ektoe, outside; derma, skin) (red).
Endoderm (Gr. endon, within).

Body-cavity, serving also as a digestive cavity, and continued into the tentacles.
MINUTE STEUCTUBE OB HISTOLOGY —

FIG. 3. Ectoderm-cells with contractile prolongations — neuro-musculnr cell-layer.

Nuclei and nematocysts in tho cells.
FIG. 4. Endoderm-cell with cilium on its inner surface.
FIGS. 5, 6. Thread-cells or nematocysts (Gr. nemu, thread ; Jiwtos, a. bag), consisting of capsule,

filament, and three recurved spines at base of thread.
REPRODUCTION OR SEXUAL PEOCESS —

FIG. 7, a. Spermatozoon (Gr. sperma, seed; zoom, an animal) with oval head and vibralile cilium.

b. Eipe ovum, consisting of vitellus or yolk, germinal vesicle or nucleus, and germinal spot or

nucleolus.

c. Impregnated ovum divided into a number of cells, surrounded by a capsule — burst to show

tho contents.
MULTIPLICATION OB. ASEXUAL PEOCESS —

Process of gemmation shown in fig. 2.
DEVELOPMENT OF HYDEOZOA —

DIAG. 2. The impregnated ovum by division becomes a mulberry-like mass or mnnda, the morula
becomes hollow by the accumulation of fluid in its interior, forming a planula, and the
planula by gradual thinning opens at one end, becoming the so-called gastrula, which
passes into the mature form.

Jfofe. In the Hydra itself there is no proper planula stage, as the two-layered form represented in c has no cilia.

CLASSIFICATION—

Sub-Kingdom — Coelenterata (Gr. Ttoilos, hollow ; enteron, an intestine), because it is composed
of two cell-layers — ectoderm and endodenn — and has no cavity separate from the body-
cavity.
Natural Order — Hydrozoa, because a digestive sac is not marked off from the body-cavity, and

the reproductive organs are external.
Genus — Hydra.
Common Name — Fresh-water Polype (Gr. poltis, many ; pous, a foot).

THE EARTH-WORM.

EXTEENAL CHARACTERS—

Fro. 1. The segmented body with a mouth at one end, an anus at the other, and a swollen portion called

the cingulum (L. a girdle) or clitellum (I., clitelhe, a saddle).
FIG. 2. Mouth situated on the 2nd segment.

External and internal pair of setse (L. sdu, bristle).

Openings of segmental organs, one on each side of all the segments except the two first.

Openings of spermathe'eae or receptacles of the spermatozoa (Gr. tperma, seed; thel;e, a repository).

Openings of vasa deferentia (L. excretory ducts) on ventral face of 15th segment

Openings of oviduct on ventral face of 14th segment.

EARTH WORM. (LUMBRICUS TERRESTRIS)-(CoNTD')

PLATE

BiLobed. Ttetis

.2. Dorsal -vi&v showing Jteftrodmctu'c & Segmented.

Diagram of Transverse Section of body thro' region of Oviduct

W SL A.K Jahnmoo. Eiinburgh Jt London

21
PLATE XI.

THE EARTH-WORM— continued.

DISPOSITION OF INTERNAL OUOANS —
FIG. 1 and DIAGKAM —

Mouth.

ALIMENTARY SYSTEM.

BLOOD SYSTEM — CIRCULATORY

' Cut end of muscular pharynx.
1 Gullet,

Crop, a dilated portion of gullet.
Gizzard, whitish, thick, and muscular.
Intestine leading straight to anus, and covered with a brownish

mass supposed to be the liver.

f Colourless corpuscles in perivisceral cavity — two shown.
Pseud-haemal vessels contractile, and therefore circulatory —
Supra-intestinal vessel (L. supra, above).
Sub-intestinal vessel (L. sub, under).
Sub-neural vessel.
Cominissural vessels connecting supra-intestinal and sub-

AND RESPIRATORY . . \ intestinal vessels.

Dilated commissural vessels in the region of the reproduc
tive organs, the so-called hearts.

Coloured fluid without corpuscles contained in pseud-hsemal
vessels acts as an oxygen-carrier, and is therefore respira
tory in function.

RENAL SYSTEM Segmental organs in pairs in each segment.

'Cerebral or prse-oral ganglia connected by commissural cords

embracing the pharynx with the
NERVOUS SYSTEM . . . . ^ Sub-cesophageal or post-oral ganglia which form the anterior

extremity of a
- Chain of ganglia extending to end of body.

0 f Ovaries and oviducts.

REPRODUCTIVE SYSTEM . . 1 ,

( iestes and vasa deferentia shown in fig. 2.

Fias. 2, 3, 4. RENAL AND REPRODUCTIVE SYSTEMS —

Segmental organs with internal ciliated opening and external pore (tig. 3).
f Anterior pair of spermathecae.
( Posterior pair of spermathecae.
f Anterior pair of bilobed testes.
( Posterior pair of testes.
f Anterior reservoir of testes with duct.
( Posterior reservoir of testes with duct.
Common vasa deferentia.

Capsulo-genous glands for secreting egg-capsules.
Ovaries.

Oviducts with wide ciliated internal opening and external opening (fig. 4).

FIG. 5. Ovary with ova. When laid the eggs are enclosed in clusters within a chitinous case, each egg
consisting of — Vitelline membrane.
Vitellus.
Germinal vesicle.
Germinal spot.

Spermatozoa from Spermatheca.
CLASSIFICATION —

Sub-Kingdom — Annelida (L. annulns, a ring), because the body is segmented ; without jointed

limbs ; nervous system forms a ring round gullet, followed by a ventral chain of ganglia.
Natural Order — Oligochae'ta (Gr. oligos, few ; chuite, hair), because the bristles are in rows, not

tufted.

Genus — Lumbricus.
Common Name — Earth-worm.

LOBSTER (HOMARUS VULGARIS)

PLATE XI I.

- •Optrung **' Aitditliry j'ac
fl. '<""' 1'au 01' Maxillae

Epipodite

23
PLATE XII.

LOBSTER AND CRAYFISH.

EXTERNAL CHARACTERS —

FIG. 1. ENTIRE SPECIMEN —

„,,,,, , ( Cervi'cal suture between head and thorax.

Copnalo-thorax (Or. kepnals, head: thorax, a breast- I

i i \ \ i. r( -\ I rental spine or rostrum (L. the beak), a

plate) covered by Carapace . . . . }

V, prolongation in front.

Abdo'men — six segments and a backward prolongation, the telson (Gr. a limit).

C Cephalic.
APPENDAGES < Thoracic, including great claws or chelae and ambulatory limbs.

(_ Abdominal, including the swimmerete.
Fio. 2. THIRD ABDOMINAL SOMITE —

f Tergum (L. the back) or dorsal portion.
BODY-SEGMENT -< Pleuron (Gr. a side).

(_ Sternum (Gr. siernon, the breast) or ventral portion.
f Proto'podite or basal portion (red).
APPENDAGES -; Exo'podite or outer terminal portion (blue).

V. Endo'podite or inner terminal portion (yellow).

FIG. 3. SIXTH ABDOMINAL SO'MITE AND TELSON: a, Lobster; b, Crayfish —
Exopodite divided transversely into two pieces.
Telson divided transversely in Crayfish, undivided in Lobster.

FIGS. 4, 5. APPENDAGES OF FIRST AND SECOND ABDOMINAL SOMITES IN THE MALE —
FIG. 4. Eudopodite, bearing a small inner process.
FIG. 5. Exopodite gone.

Endopodites grooved inwardly, so that the two scooped portions brought together form a

kind of channel.
FIG. 6. APPENDAGES IN ORDER —

1. Ophthalmites or eye-stalks (Gr. ophtlialmos, the eye).

2. Anten'nules with opening of auditory sac.

3. Anten'nse or feelers with opening of green gland.
HEAD — six pair 4. Mandibles (L. mando, I chew).

5. Maxillae, iirst pair.

G. Maxillae, second pair with boat-shaped scaphognathite (Gr. sJcapJie, a boat ;

(jnuthos, a jaw) for baling out and drawing in water (blue and green).
Maxillipedes or foot-jaws —
7. First pair, epipodite (green) without a gill.

3. Second pair, epipodite gill-bearing.

THORAX— eight „,, . ,

9. llnrd pair, epipodite gill-bearing.

Chelae or pincers (Gr. chele, a claw), epipodite gill-bearing (fig. 1).
10. Ambulatory limb (L. ambulare, to walk), epipodite gill-bearing.

The four pair are seen in fig. 1.
ABDOMEN — six pair (see figs. 1-5).
NOTE. — Seven joints of chelte and ambulatory limbs are named in order as follows (see No. 10) —

1. Coxo'podito (L. coxa, the hip) or proximal joint.

2. Basi'podite . . . . )

3. Ischio'podite (Gr. ischion, the hip) j fused to§ethcr lu chela"

4. Mero'podite (Gr. meros, the thigh).

5. Carpo'podite (Gr. karpos, wrist).

6. Pro'podite (Gr. pro, in front of).

7. Dactylo'podite (Gr. daktulos, a finger) or terminal joint.
Six joints of antenna in order (see No. 3) —

Coxo'cerito (Gr. kerus, a horn).

Basi'cerite articulated with an outer llat plate, scaphocerite.

Ischio'cerite.

Mero'cerite.

Carpo'cerite.

Pro'cerite, the long many-jointed feeler.

LOBSTER (HOMARUS VULGARIS)— CONT"

TLATE XIII.

Fig.!, longitudinal Horizontal Section 'Female;

Fig. 2. Longitudinal Vertical Sectjpn [Male

Fig.3. FRESH-WATER CRAYFISH (ASTA.CUS FLUVIATILIS

(Female |

V. * A K JoLaeion K.Unburgfi t Lundui

25

PLATE XIII.

LOBSTER AND CRAYFISH—

GENERAL ARRANGEMENT OF INTERNAL GROANS —

Fius. 1, 2, 3. HODY IN SECTIONAL PLAN AND ELEVATION—

/ Mouth.
I Gullet.

I Stomach, with its cardiac or anterior end (Or. kardia, the heart), and its
ALIMENTARY SYSTEM ( pyloric or posterior end ((Jr. puloros, a gatekeeper) leading into

I Intestine ending in
I Anus.
\ Liver made up of two symmetrical halves.

CIRCULATORY SYSTEM

( Arteries — eternal, superior abdominal, and inferior abdominal.

RKSPIRATORY SYSTEM — Branchiae (Gr. gills), twenty on each side in Lobster, eighteen in Crayfish.
UENAL SYSTEM — Green glands situated at the base of antenna;.

( Supra-cesophageal ganglia.
NERVOUS SYSTEM , J Circum-oesophageal commissures.

I bub-ccsophageal ganglia.

V Chain of eleven ganglia.

f Testes with their vasa deferentia opening on the base of last thoracic

REPRODUCTIVE SYSTEM appendages (fig. 2).

i Ovaries with their oviducts opening on the base of lust thoracic appcn-
V dages but two (lig. 3).

4

LOBSTER (HOMARUS VULGARIS)— COST"-

PLATE XIV.

Fig

Fjg.2. tStcttffn tf Stomach

J'osterwr fturiian sffrutittm. the- front.

Diag. 2 FJ(\tilion &. Plan of Meari

Fig 4-. Gastric skeleton -tfidf. wo/v
osti/cle.

or Pottenor piece

Diag. I. G_rajlator\

Diag .3. Ovwrv after Tya&finff through

ZOC<L of Lobster- -just Itft th

Fig. 5. 7cs&s &. Spermatozoon*-

Fig.7. Oru- fijh-- - urf (/- leaves ttif egq

A

' 4A K..Tohn«lon. Edinburgh t Londoi

27

PLATE XIV.

LOBSTER AND CRAYFISH— continued.

ALIMKKTAKV SYSTEM —

FIG. 1. STOMACH in Elevation and Plan —

• Anterior or cardiac.

Posterior or pyloric, the anterior part of which is the prepyloric.

( Cardiac region-cardiac ossicle { Averse piece.

( Urocardiac proces

llEOIONS }
\

SKFLFT \ ^ Urocardiac process, a median prolongation.

^ Prepyloric region — median prepyloric ossicle (green).
(.Pyl

. Pyloric region — transverse pyloric ossicle.
FIGS. 2, 3, 4. DKT.ULED STRUCTURE OF GASTRIC SKELETON —
Ossicles —

Cardiac, with urocardiac process.

Prepyloric (lig. 4).

Pyloric (fig. 4).

Lateral j Anterior pair (figs. 3 and 4).

( Posterior pair.
Teeth of—

Lateral posterior ossicles.
Prepyloric ossicle — a single median tooth.
CIRCULATORY AND RESPIRATORY SYSTEMS —

DIAG. 1. CIRCULATORY AND RESPIRATORY ORGANS —

Heart, rhythmically contractile and systemic — that is, it propels the blood received from the gills

through the system!

Pericardium, a cavity surrounding the heart.
Arteries carrying the blood to —
Eye, ophthalmic.
Antenna, antennary.

liest of body, sternal with / Sul)c"ur aWo"»nal *>«"><*.

( Inferior abdominal branch.

Veins, gather up blood and carry it to gills for aeration.

llranchio-cardiac canals, carry blood from gills to pericardium.

Valvular openings, by which the blood in pericardium enters heart.

Gills, each consisting of a central stem with an ascending blood-vessel uu its outer side leading
from venous sinus, and a descending blood-vessel on its inner side leading to branchio-
cardiac canals. The stem is beset with fine filaments which repeat the structure of the stem.
DIAG. 2. ELEVATION AND PLAN OF HEART —

1 Ophthalmic.

2 Antennary.

"" 2 Hepatic (Gr. Itcpar, hepatos, the liver).
. 1 Sternal, with its superior abdominal branch.
( 2 Superior.

VALVULAR APERTURES -< 2 Lateral.
V 2 Inferior.

Pericardia! cavity, so-called pericardium.
Fibrous tissue, two pair of bands holding heart in place.

28

REPRODUCTIVE SYSTEM —

FIG. 5. MALE ORGANS detached (seen in situ PI. XIII. fig. 2) —
Testes, make spermatozoa.

Yas deferens, tube for conveying spermatozoa out of body.
Spermatozoon, cilia absent.
DIAG. 3. OVUM OF CRAYFISH just hatched —

Outer and inner membranous coats produced at one point into a process for attachment to the

body of parent.
Albumen.

Vitelliue membrane,
Vitellus.
DEVELOPMENT —

FIG. 6. Young Lobster as it emerges from egg, a zo'ea which passes by metamorphosis into adult form.

FIG. 7. Young Craylish as it emerges from egg, essentially similar to adult,, no zoea stage.

FIG. 8. Adult Crayfish showing appendages.

FIG. 9. Limbs used for masticatory purposes, laid out.

LOBSTER (HOMARUS VULGARIS)— COST"

PLATE XV-

Thoracic
ganglia. \

with* diagonal furrtnv
&coilraJ_ depression, /spotj

On* ol 'the/ radiating fibres
traced front Cornea, to Optic gangtum,

Fig. 12 Striped Mi ^

Fig 10 falourtesynwifated corpus^** of the bloO(L,luyhlyin»i<fnilifd
various shapes *

W kA K Jilnuton Edu»™rgli

29

PLATE XV.

J_lO-DQ J. -ER continued.

NERVOUS SYSTEM-
FIG. 1. VENTRAL CHAIN of 13 GANGLIA united by commissures —

Cerebral or supra-oesopliageal ganglia anterior to gullet, giving olf optic nerves.
CircunwEsophageal commissures round gullet.
Sub-O3sopliageal ganglia posterior to gullet.

5 Kemaining thoracic ganglia, united to one another by double nerve-cords.

6 Abdominal ganglia, united to one another by single nerve-cords.

Note. — The numbers attached to ganglia denote the cephalic, thoracic, or abdominal segments to which they belong.
FIG. 2. VISCERAL NERVES in Elevation and Plan —
Nerves arising from—

Cerebral ganglia — A'zygos — median, and branching posteriorly to form lateral azygos.
( MandiLmlar.

COMMISSURAI GANGLY J Anteio-latemL

) Medio-lateral.
V. Postero-lateral.

Hepatic formed by the union of postero-latural and lateral azygos.
SENSORY ORGANS —

FIGS. 3, 4. GENERAL STRUCTURE OF EYE —

Cor'nea, the transparent cuticle divided into a number of four-sided areas or facets (fig. 4).
Radiating fibres (two are coloured red).
Optic nerve expanding into optic ganglion.
Flexible stalk.
FIG. 5. MINUTE STRUCTURE of one of the elements of the COMPOUND EYE —

Cornea.
/ Cone.

NERVOUS ELEMENTS

» Spindle.

' Nerve-fibril continuous with ganglion.
i Investing nervous elements and ganglion.
SHEYTII J Outer end continuous with cornea.

J Inner end continuous with adjacent sheaths.
V. Oval nuclei and pigment layers.
I)IAG. 2. FORMATION OF THE VERTEBRATE EYE —

a. Optic vesicle, a hollow process of the- brain, involution of integument meeting it and pushing

it in.

I). Crystalline lens, a detached portion of thickened integument.
c. Retina, the wall of the doubled-up optic vesicle nearest the lens (red).

Choroid, the wall nearest the brain (blue).

Eod and cone layer of retina embedded in the choroid by obliteration of the cavity between.
DIAG. 1. NERVOUS ELEMENTS OF RETINA compared with nervous elements of fig. 5—
Rod, cone, and outer granular layers = cone, rod, and spindle.
Nerve-fibrils continuous with optic ganglion in both,
FIG. 6. Base of antennule cut open to show auditory sac.
FIG. 7. SECTION THROUGH AUDITORY SAC —
Auditory opening.
Sac, an involution of the integument lined by hairlike filaments and containing fluid and grains

of sand.

Auditory nerve from cerebral ganglia.
FIG. 8. Hairlike filaments magnified.

30

EXOSKELETON —

FIG. 9. Vertical section of shell or exoskcleton.

The epidermis thrusts off successive layers of its substance, which form a number of delicate
laminse superimposed upon one another, and this is impregnated with salts of lime. The
exoskeleton thus formed is cuticular, to be distinguished from cornified epidermis, as nails,
composed of modified cells, a cellular exoskeleton.
CLASSIFICATION—

Sub-Kingdom — Arthro'poda (Gr. arthron, a joint; pous, a foot). The body is segmented;
limbs jointed ; nervous system forms a ring round gullet, followed by a ventral chain of
ganglia.
Natural Order — Crustacea (L. cnista, a crust), because it breathes by gills ; has two pair of

antennae (lesser and greater) ; walking legs borne by thorax and abdomen.
Genera — Honiarus, Astacus.
Common Names — Lobster, Crayfish.

FRESH WATER MUSSEL (ANODONTA CYNEA).

PLATE XVL

Fi g. I . a Side i (,-H - Ufi mantff fcbt

Dorsal viav-yn^xtrOin™. laut, open, £ h*art tv.rned.' bach

'•JoiftiiLg Gcrrliral Gttrw&i
$S$\S Stamat*.'

& Jftrvou* Syst

Rectum, po*xmg thro heart

Tromntrse Jcctiori- thremffft/ hearts.
D0r*al

T i A K Joho-um Edinburgh L

31
PLATE XVI.

THE FRESH- WATER MUSSEL.

GENERAL STRUCTURE OF BODY —

FIG. 1, a. SIDE VIEW OF ANIMAL when left valve and left mantle-lobe are removed —

Mouth, anterior.

Anus, posterior.

Heart, dorsal.

Foot, ventral.

Gills, lateral, inner and outer.

Labial palps, two on each side of month.

Adductor muscles, anterior and posterior, for closing the shelL

Right lobo of mantle, lateral.
Fia. 1, 6. DORSAL VIEW OF ANIMAL, partly dissected —

Heart.

Pericardium.

Vena cava in floor of pericardium.

Organ of Bojanus beneath pericardium.

Intestine entering pericardium.
PIAO. 1. TRANSVERSE SECTION OF ANIMAL —

Mantle-lobes, right and left, lateral extensions of the dorsal integument.

Outer gill made up of two lamella;.

Inner gill made up of two lamellae.

Foot, median.

Pericardium.

( Ventricle.
Heart •{ ,r . ,

( 1 wo auricles.

Intestine piercing ventricle.
Vena cava.

Organ of Bojanus, beneath pericardium.
ALIMENTARY AND NERVOUS SYSTEMS — •

FIG. 2, a. ALIMENTARY SYSTEM — Mantle and gills removed on left side, and coiled intestine dissected

out in foot.

Mouth, below anterior adductor.
Gullet.
Stomach.

Intestine, with neural flexure.
Anus, above posterior adductor.
FIG. 2, a and 1. NERVOUS SYSTEM DISSECTED OUT —

Cerebral or cephalic ganglia, two at base of labial palps.

Pedal ganglia, two united and embedded in foot.

Puri'eto-splanchuic ganglia (L. parietes, walls ; Gr. splanclma, the entrails), beneath posterior

adductor.

Commissures uniting pedal and parieto-splanchnic with cerebral ganglia.
SENSE ORGANS —

FIG. 3. Cyclas cornea, a fresh-water form belonging to the same natural order as Anodon, in the foot

of which the auditory organ can be conveniently examined under the microscope.
FIG. 4. AUDITORY ORGAN OF CYCLAS —

Auditory sac lined with ciliated cells and containing fluid and an otolith in the centra
Auditory nerve from pedal ganglion (not shown).
CIRCULATORY AND RENAL SYSTEMS —

FIG. 5. THE ORGAN OF BOJANUS dissected from left side, left auricle turned up —

( Auricles receiving blood from gills.

HEART (Systemic) J Ventricle with anterior aorta and posterior aorta distributing blood to
(. the body.

32

Vena eava receiving the Wood of the body which passes through the organ of Bojanus to the
gills.

( Transparent uon glandular portion or vestibule communicating with
ORGAN OF * exterior and with the
BOJANUS \ Brownish glandular portion communicating with pericardium by two

V. oval openings (see fig. 1, I).
RESPIRATORY SYSTEM —

Fio. G, a. GENERAL STRUCTURE OF GILL, section through line ab in diagram 1 —
Inner and outer lamellae.

Partitions between lamellae — interlamellar partitions.

Pairs of chitinous rods in the parallel and vertical gill-filaments, indicated by pairs of dots.
FIG. 6, J>. MINUTE STRUCTURE OF GILL, section of lamella parallel to surface in region of chilinous rods —
Gill-h'lament strengthened by pair of chitinous rods.
Openings between filaments furnished with ciliated epithelium.
Partitions between filaments, interfilamentar, consisting of horizontal and obliquely crossed

fibres.

MUSCULAR SYSTEM —
FIG. 7. MUSCLES —

Anterior and posterior adductors, adducting or bringing together the valves.

Protractor of foot.

Anterior retractor of foot.

Posterior retractor of foot.

Smaller retractors arising near umbo, impressions only shown (fig. 8, a).

EXOSKELETON

Fio. 8, b. EXTERIOR OF SFIELL —

Rounded anterior end, tapering posterior end.

Umbo or beak on dorsal surface of each valve towards anterior end.
Concentric lines of growth.

Elastic ligament behind umbones, binding the two valves together, and tending to open the
valves. The hinge-line is without interlocking processes or teeth, hence the name Anodon
(Gr. a, without ; odous, odontos, a tooth).
Fio. 8, a. INTERIOR OF SHELL —

Pallial impression indicating attachment of muscular ventral edge of mantle to shell.

Anterior and posterior adductor impressions.

Successive adductor impressions, extending from cavity of umbo to each adductor muscle,

and indicating the travelling downwards of adductor muscles.
HISTOLOGY —

FIG. 9, a. Liver invests stomach, and consists of blind tubes lined with epithelial cells.

b. Muscle composed of elongated nucleated cells resembling those of smooth muscle in form

(PI. XXIV. fig. 7), but having the structure of striped muscle.

c. Blood-corpuscles, colourless, nucleated, and amoeboid.
DEVELOPMENT —

FIG. 10, a. Eipe ovum with its vitelline membrane forming a short tube at one point with an opening

or micropyle.

It, c. Embryo when hatched or Glochidium — b enclosed in vitelline membrane, c escaped from it.
( Valves of shell triangular (see fig. 6), united at base and incurved at
DIFFERENCES \ apex.
FROM ADULT "j Single adductor muscle.

V. Byssus or beard coming off from foot.
CLASSIFICATION—

Sub-Kingdom — Mollusca (L. mollis, soft). The body is soft and unsegmented ; possesses a

shell, and three pair of nervous ganglia.
Natural Order — Lamellibranchiata (L. lamella, a plate ; Gr. bronchia, a gill), because it has

a bivalve shell ; a two-lobed mantle ; plate-like gills ; and no distinct head.
Genus — Anodon'ta (Gr. a, without ; odous, odontos, a tooth).
Common Name — Fresh-water Mussel.

EDIBLE SNATL(HELEX POMATIA).

PLATE XVII.

Fi'4. 1 . Bf&ix. porndtia

Fig. 3 iotitjibtduuil Vertical Jectitm

3ettu*n> of Mefttan.

V\ Qdontnphtm,

~~

JS^O

'Refractor of biurcaJL mass
Qiag.l.Zcm/' Jfrt . tt'fffitffi />/

Frtf .6 . #•. St'rnv upper la

/>. Limy- Ta-tica/' oeeoan

/»./T>,« ofOdontafhon,

Posterior aid f)f Radula* -X^- J,

0-ng.l. Grculaiory Centre*

L

Fig*. 4 Dorsal vtfw with ths ttpptr
- ofjnantb turned back

Conjunctiva- --' '
Corneas"

tmrrottf jwtti&n \\'»'fiff</ Jrwmsb&uaucL

Fig. 12 Blind end rf Follicle <>/'(h-otrstig

\-pef •nmtt'iim formou} internolbf

fully tirrmrit •SptrmaAno^

m ftmd/

canal; pntbablf
eammunLeating -with eattrior

vr kA K Juhmtun Edmburfn i, London

PLATE XVII.

THE EDIBLE SNAIL.

EXTERNAL CHARACTERS —

FIG. 1. THE SNAIL protruded from its shell —

, . [ Pair of tentacles or eye-stalks with eyes.
HEAD bearing * /

I Pair of tentacles without eyes.

Foot flattened out ventrally, lieiice the name Gasteropod (Gr. gaster, the belly ; pous, a foot).

Shell univalve and spiral.
Fio. 2. SHELL —

Body-whorl, the last and largest whorl with the inouth.

Spire, the rest of the whorls.

Five brown bands running in the direction of the spire.

Lines of growth running in a longitudinal direction from apex (shown in fig. 1 ).
G KNERAL STRUCTURE OF BODY-
FIG. 3. SECTION OF BODY, shell and viscera removed —

Parts of body — foot, mantle, visceral sac, pulmonary chamber.

BUCCAL CAVITY { Roof with horny Jaw>

1 Floor with odontophore (Gr. odous, odontos, a tooth ; pJiorec, I bear).

(Esophagus.
Piectum seen in section.

Nervous ganglia seen in section above and below gullet.
Columellar muscle attaching body to shell.

Fie. 4. COMMON SNAIL with shell removed and covering of pulmonary chamber turned buck —
Heart consisting of auricle and ventricle.
Blood-vessels ramifying in wall of pulmonary chamber.
Renal organ or kidney for getting rid of nitrogenous waste.
Pulmonary aperture leading into the modified mantle-cavity or pulmonary cliamler, with anus

beside it.
ALIMENTARY SYSTEM —

FIG. 5 «. BUCCAL MASS removed from body —
Protractor and retractor muscles.
(Esophagus and duct of salivary gland leading from it.
FIG. 5 6, and DIAG. 1. ODON'TOPHORE IN SECTION —
Skeleton formed of cartilage (blue).
Sub-radular membrane with its muscles (yellow).

Radula (L. a scraper), the surface of sub-radular membrane beset with cuticular teeth (red).
FIG. G—

a. Horny upper jaw detached.
6. Teeth of radula arranged in transverse rows.

Fio. 7. DISSECTION FROM DORSAL SURFACE, with organs gently separated and laid out —

|' Buccal mass.
I Gullet dilating into crop.
ALIMENTARY SYSTEM . ( Salivary gland embracing crop.

) Stomach, with a pyloric caecum near liver.
I Liver, with coiled intestine embedded in it.

CIRCULATORY SYSTEM / y«ltricle (^cle not shown).

( Aorta.

RESPIRATORY SYSTEM . Pulmonary chamber, with blood-vessels on wall.
PiENAL ORGAN . . . Nephridium (Gr. nep/iroi, kidneys) or kidney fur getting rid oi

nitrogenous waste.
E

34

Ovo-testis or hermaphrodite gland embedded in liver, consisting of
tubes in which ova and spermatozoa are developed.

The blind end of one of the tubes with its contained ova and sper
matozoa shown in fig. 12.
Duct of ovo-testis.
Albumen-gland forming an albuminous secretion.

Vas deferens or duct for conveying spermatozoa, opening into penis.
\ /-\ • i . * * -i- .

i Oviduct for conveying ova, ending in vagina.

Spermatheca or receptaculum semiuis (L. receptacle of the semen)

opening into vagina.
Penis with long flagellum (L. a whip), an eversible involution of

the integument.

Dart-sac eversible, with pointed dart 1 ,. C( ., ,, .,

, , > peculiar to Snail family.

.Mucous glands J

CIRCULATORY SYSTEM

DlAG. 2. COMPAEATIVE VlEW OF CENTRES OF CIRCULATION in

a. Worm — Dorsal trunk with transverse vessels discharging into it.

6. Anodon — Dorsal trunk dilated=the ventricle, and transverse vessels reduced to a pair forming

the two auricles.

c. Snail — Dorsal trunk bent upon itself =the ventricle sending blood to anterior end of body by
cephalic artery, and to posterior end by abdominal artery. Transverse vessels reduced to
one, the right, forming the auricle.
FIG. 8. COLOURLESS CORPUSCLES OF THE BLOOD.
NERVOUS SYSTEM AND SENSE ORGANS —

FIG. 9. NERVOUS SYSTEM forming a ring round gullet —
Cerebral or supra-resophagcal ganglia.

Sub-oesophageal ganglia j Peda1' anterior ancl ™itod with cerebral *>* comni;ssureS.
( Parieto-splanchnic united with cerebral by commissures.

FIG. 10. EYES, a pair, placed at end of tentacles —

Sclerot'ic (Gr. sJcleros, hard) passing into a cuticular cornea.

Clioroid, the pigmented layer.

Optic nerve expanding into an outer retina, the fibres of which pass through the choroid to form
an inner retina with rods and cones nearest the light.

Vitreous humour (not shown).

Lens.

Cornea with a conjunctiva on its outer surface.
FIG. 11. ORGANS OF HEARING, a pair close to pedal ganglia — •

Auditory canal.

Sac containing fluid and otoliths.

Auditory nerve from cerebral ganglia (not shown).
DEVELOPMENT —

DIAG. 3. EARLY STAGES OF DEVELOPMENT OF A VELIGEROTJS GASTEROPOD, no evident velum in Snail-
Ciliated velum, an expansion of the integument about the head.

Foot developing, with operculum (L. a lid) upon it.

Shell external.
CLASSIFICATION—

Sub-Kingdom — Mollusca.

Natural Order — Odonto'phora, because it has a distinct head ; and an Odontophore.

Genus — Helix (Gr. a spiral), from the spiral form of the univalve shell.

Common Name — Snail.

EDIBLE FROG(RANA ESCULENTA)

PLATE XVIII.

Fig. 2. DisgectLvru from, th* venfraJ ftdf

(McuUj

Carpus ojizpos aj7\; ^

Diagram l. Transverse Section of Abdomen.

Di a 6 ram 2 . Transverse Section of
o

Vertebrate & Invertebrate

Sympathetic nervous

7. ~7erl£ht~*aie- b Inverted rate' lyinq on,

isiai Ti£J'wyus syste
rd,

i£. 3. Loriyitotdcrial, veri_i£al station., with th? parts laid- out. f ft

Bristle DiutSfd, -uilo Anterior &-, oui >.>f Posteriar rzostrii^

\ Bri.#U.f passi'J ifu'^u^fi lyrrifaTU^ cosily &

JJnirn

sjuct SMTL, tJu'viigh

l- at'

W tA-KJolinswu. Edmburg*h I Londo

35

•

PLATE XVIII.

THE FKOGK

EXTERNAL CHARACTERS —

FIG. 1. FROG with Limbs extended —

Anterior narea or external nares (L. nares, the nostrils).
Eye.

Tympan'ic membrane or membrana tym'pani (L. tympanum, a drum).
Cutaneous pouch (L. cutis, the skin).
Clo'acal aperture (L. cloaca, a sewer).
f Brachium (L. the arm).
\ Antebrachium (L. ante, before).

FORE-LIMI! •< Manu3 (L- tho hand).

^ Four digits (L. digilus, tho linger or toe).
f Femur (L. the thigh).

HIND-LIMB \ ^.^ °, lef>'
1 PCS (L. the foot).

\ Five digits.
GENERAL DISPOSITION OF INTERNAL ORGANS —

FIG. 2. DISSECTION from the Ventral Surface to show VISCERA, Thoracic and Abdominal —

( Ventricle.
1 | Two auricles.
Lungs, right and left.
Stomach and intestine.

Liver with gall-bladder, pancreas, and spleen.
Urinary bladder.

Corpus adiposum (L. fatty body), finger-like yellow processes.
Testis, only one shown.

DIAG. 1. TRANSVERSE SECTION THROUGH ABDOMEN-
NEURAL CANAL containing Spinal cord.

I Lining membrane or pleuropcritoncal membrane (Or.

pleuron, a rib ; peri, around ; teino, I stretch).
Alimentary canal suspended by two layers of the
membrane coming together in tho middle line — the

PLEUROPERITONE'AL CAVITY =

mes'entery (Gr. mesos, middle ; enteron, intestine).

THORACIC CAVITY lined by the pleura, I Testes suspended in the same way by the mesorchium

and ABDOMINAL CAVITY lined by the \ (Gr. orchis, a testicle).

peritoneum in Man. Kidneys held in place by the membrane covering their

ventral faces.

Sympathetic nervous system, two gangliated cords con
tained in triangular space formed by the layers of
membrane converging to form mesentery.
\ Dorsal aorta.
DIAG. 2. COMPARISON OP A TRANSVERSE SECTION OF A VERTEBRATE (FROG) AND AN INVERTEBBATE

(LOBSTER) —

Invertebrate — Vertebrate —

Visceral tube only. Visceral tube.

Neural tube.
Notochord (Gr. notos, the back ; chorde, a string), the

primitive axial column, separating the two tubes.
Limbs on neural or nerve side of body. Limbs on hamial or heart side of body.

30

FIG. 3. THE LIMBS on the left side are removed, together with the left walls of the cerebro-spinal,
thoraco-abdominal, and buccal cavities. The alimentary canal is laid out to display it to
advantage — -

Mouth with posterior nostril, and Eustachian recess con
tinuous with tympanic cavity.
Tongue turned forward to show its attachment.
Teeth in upper jaw and on palate.
Stomach.

/ Small intestine succeeding stomach.
ALIMENTARY SYSTEM . . . . \ T .. . * . .

Large intestine terminating in cloaca.

Liver lobed.

Pancreas or "sweetbread," pale coloured, near pyloric

portion of stomach.
Spleen, red, near the commencement of twisted portion

of intestine.

( Dorsal aorta.
CIRCULATORY SYSTEM .... •< T . .

( Inferior vena cava.

EESPIKATORY SYSTEM j fff' a sUt in flo0r of ^^^ leadinS into lunS3'

( Left lung.

• j Eight ovary.

I Oviduct, anterior coiled portion of right and terminal

RENAL AND REPRODUCTIVE SYSTEMS ( dilated portion of left (see PL XXII. fig. 8).

j Left kidney with ureter.
( Urinary bladder, bilobed.

NERVOUS SYSTEM Brain and spinal cord.

SKELETON Vert'ebral column enclosing spinal cord, and Skull enclosing

brain.
FIG. 4. ALIMENTARY CANAL removed from body —

(ESOPHAGUS or gullet communicating with pharynx.

f Cardiac or anterior portion.

STOMACH f . .

( Pyloric portion leading into intestine.

SMALL INTESTINE -[ Duode'num forming a loop with the stomach.

( Heum, the twisted portion (Gr. eilein, to twist).
LAKGE INTESTINE f Colon, the dilated portion into which the ileum opens.

( Rectum (L. the seat) opening into cloaca.

EDIBLE FROG(RANA ESCU LENTA)— CONT°-

PLATE XIX.

. I. -SlaiH tlsirsaL vie*

Stcull - laJiral - view

2 . SknU ventral vwv - fnwer ja»

l^Jngal0 splemal
Fig 4-. SktlJl-poslfrujr

6. CartilagirwBJ sfaill - vnutral

7. Vertebral cttfumn. &
Pelvic Girdlt -Jursal

Fig. 3- Prostyle,

_. -Ctntmm,

SmtL-HmA rf EdiMt. . fna ,. , ,,

Fij 13 Parc.-lurCb 'if (.

Pabis

Diagram of Typical Vertebrate Limb

12 Jterteutn fc Shoulder -irdl

\\ " V N. phalxnge*

i A.K .l(.hn»Wtt. Edinburgh \ London

37

PLATE XIX.

THE FROG — continued.

SKELETON.

*.* The colours in left-hand corner of Plate refer only to Skull
THE BONY SKULL —

Fio. 1. DORSAL VIEW —

Exoccipitals (L. ex, out ; occiput, the back of the head).
Pro-otics (Gr. pro, in front of; ous, olos, the ear).

Parietals (L. paries, a wall) . . )

•T-I i i A- S li * i i\ > united in adult.

Frontals (L. frons, the forehead) )

Nasals.

PremaxilliB (L. pros, before ; maxilla, the upper jaw).
FIG. 2. VENTRAL VIEW, lower jaw removed —

Parasphen'oid (Gr. sphen, a wedge).

Sphenethmoid or girdle-bone.

Voiuers with teeth.

Premaxilla! with teeth.

Pterygoids (Gr. pteron, a wing).

Palatines, slender palate bones.
Fio. 3. SIDE VIEW—

Squamosals.

Quadrato-j ugals.

Maxillae with teeth.

Premaxilla} with teeth.

Mandible or lower jaw, consisting of two rami (L. ramus, a branch) without teeth.
/ Meckel's cartilage forming the core.

\ Angulo-splenial . . ) .

HAMUS -< -r- ... .-, c investing Mockers cartilage.

^ Dentary without teeth )

V Mento-Meckelian bone (L. mentum, the chin), the ossified tip of Meckel's cartilage.
Fio. 4. POSTERIOR VIEW —

Exoccipitals with condyles (Gr. kondulos, a knuckle) for articulation with vertebral column.
Foramen magnum (L. great opening), through which spinal cord passes into brain.
THE CARTILAGINOUS SKULL —
FIG. 5. DORSAL VIEW —

Sphenethmoid bone, replacing cartilage and partly covered by the f rentals (see fig. 1).
Nasal roof covered by nasals.
Foutanelles, membranous portions.
FIG. 6. VENTRAL VIEW —
Sphenethmoid bone.

Nasal floor anterior to Sphenethmoid covered by vomers.
Floor posterior to Sphenethmoid from the exoccipitals covered by the parasphenoid, which partly

overlaps Sphenethmoid.

Pterygoid bar, replaced by pterygoid and palatine bones (see fig. 2).
FIGS. 5, 6. MANDIBULAR SUSPENSORIUM, connecting lower jaw with skull —
Posterior end articulating with Meckel's cartilage.

Anterior end dividing j" Dorsal process or eras attached to outer wall of skull,
into ( Ventral process or crus continuous with pterygoid bar.

Note. — Two kinds of bone are distinguished in the skull according to their mode of origin —

1. Cartilage bones (red), as the name denotes, are first modelled in cartilage.

2. Membrane or splint bones (blue) are those not so preformed in cartilage.

38

FIGS. 7, 8, 9. THE VERTEBRAL COLUMN or BACKBONE = 9 bony segments or vertebrae and a bony
prolongation or urostyle (Gr. oura, a tail) —

( Body or centrum.

VERTEBRA . . . . \ C Neural spine or spinous process.

(. Neural arch. 1 Transverse processes.

V. Zygapo'physes (Gr. zugos, an articulation).

ATLAS or 1st vertebra with which the two occipital condyles of the skull articulate.
SACRUM or 9th vertebra with which the pelvic girdle articulates.

/ Thickened anterior end with two concavities into which the two con-
J vexities of the sacrum fit (fig. 9, a).
UROSTYLE or < DCYX < gciatjc nerV6) tjje nerye Of ^ iegj passing out from neural canal by a

small opening (red).
FIG. 10. PELVIC ARCH, side view—

'Acetab'ulum, the socket into which the head of the thigh-bone or
femur fits.

PELVIC ARCH or HIP-
GIRDLE ....

Ilium or haunch-bone articulating with sacrum.
Ischium, a posterior rounded bone.

Pubis, a ventral wedge between ilium and ischium.
..Triradiate junction of the three bones in the acetabulum.
FIG. 11. HYOID—
BODY.

f Anterior attached to skull (see fig. 2).
PROCESSES OR CORNUA } Lateral.
(L. horns) . . . ^ Posterior.

v. Thyro-hyals, sometimes called posterior cornua.
FIG. 12. STERNUM and SHOULDEE-GIEDLE —

T, ( Anterior piece — Omo-sternum (Gr. omos, the shoulder).

STERNUM or BREAST- '

T. -< Median piece — Sternum proper.

(. Posterior piece — Xiphi-sternum (Gr. xiphos, a sword).
/ Glenoidal cavity, the socket into which the head of the humerus fits.
PECTORAL ARCH or } Dorsal portion — Scapula or shoulder-blade, and Supra-scapula.

SHOULDER-GIRDLE } TT ( Coracoids.

I Ventral portions 1 rn • i n t.

V ( Clavicle or collar-bone.

FIG. 13. EIGHT FORE-LIMB, dorsal surface —

Humerus.

Radius and ulna united.

Carpals or wrist-bones.

Five digits consisting of metacarpals and phalanges (first digit rudimentary =Pollex, L. thumb).
FIG. 14. LEFT HIND-LIMB, dorsal surface —

Femur or thigh-bone.

Tibia and fibula united.

Tarsals with elongated astragalus and calcaneum.

Five digits consisting of metatarsals and phalanges.

Calcar (L. a spur), a horny projection at base of first digit or hallux (L. haltex, the big toe).
DIAGRAM. THE CORRESPONDING BONES IN THE FORE AND HIND LIMBS WITH THEIR RESPECTIVE ARCHES —

The axis (an imaginary line passing through the middle of the limb to the end of the third digit)
divides the limb into a preaxial and a postaxial portion.

Carpus or tarsus consists of two rows of bones with a centrale between, and the following are
thus named in human anatomy : —

Eadiale = Scaphoid. Tibiale l_At >

Intermedium = Lunar. Intermedium j ~

Ulnare = Cu'neif orm. Fibulare = Calca'neum.

Centrale, not represented. Centrale =Navicula're.

EDIBLE FROG(RANA ESCULENTA)— CONT°-

PLATE

Fig. I. Artfrit* ventral

Carotid, tru/tk.

4 portion ofGapiBary network,

\

Cartilages ofLaryn;f/<& Trachea

Pigment cell

fcA K John.uiti Edinturgh t London

39

PLATE XX.

THE FKOG--

-continued.

CIRCULATORY SYSTEM —
FIG. 1. ARTERIES —

f Lingual artery (L. lingua, the tongue) to tongue.
CAUOT'ID TRUNK OR AN- J Carotid gland.

TERIOE AORTIC ARCH \ Carotid artery to head by way of ear (Gr. kara, the head ; mis, the
( ear).

/ Vertebral artery to vertebral column.

f Sub-clavian artery (L. sub, under; davicula, collar-bone) to forelimb.

(Esophageal artery to gullet.

Cceliac artery ( Hepatic to liver.

(Gr. koilia, the belly) \ Gastric to stomach.

( Splenic to spleen.
Mesenteric artery 1
/ ( Haemal to intestine (not named).

Dorsal aorta, giving off branches to various organs.

Common iliac arteries formed by the forking of the aorta in the
neighbourhood of the ilium, and giving off hypogastric branches
to the bladder and lower parts of the belly.

Femoral and sciatic arteries, a continuation of the common iliac
down the thigh.

AORTIC TRUNK OK
MIDDLE AORTIC
AUCH

PULMO-CUTANEOUS
TRUNK OR POS
TERIOR AORTIC

ARCH

Fio. 2. VEINS —

SUPERIOR VENA CAVA,
FORMED BY

INFERIOR VENA CAVA,
FORMED BY

\ Pul'monary artery to lung (L. pulmo, a lung).

j Cutaneous artery to the skin of the back (L. cutis, the skin).

C Innominate, formed by / Internal jugular.
( bub-scapular.

I Sub-clavian, formed by •!

( Bruehial.

* External jugular.
( Renal.

•< Genital (not shown).
(. Hepat'ic.

Musculo-cutaneous.

COMMON ILIAC or RENAL AFFERENT VEIN formed by the dorsal ends of the pelvic vein, which is

formed by the femoral and sciatic veins. Dorso-lumbar vein opens into common iliac.
ANTERIOR ABDOMINAL VEIN formed by the ventral ends of the pelvic vein.

f Gastric.
PORTAL VEIN or VENA PORT.E (L. the vein of the gate — of the liver) formed by •< Lieno-intestinal (L.

V lienis, the spleen).
COMMON PULMONARY VEIN formed by the veins of the right and left lungs.

DIAGRAM I. THE HEART, with the principal vessels distributing and returning the blood —

f Sinus venosus (L. venous sinus) receiving superior and inferior
venae cavae.

HEART •{ Right auricle with sinus venosus opening into it

Left auricle receiving common pulmonary vein.
L Ventricle leading into truncus arteriosus (L. arterial trunk).

40

( Carotid supplying the parts about the head, including the brain.

FBINCIPAL ARTERIAL TRUNKS J Pulmo-cutaneous supplying the lungs and dorsal integument.

(. Aortic supplying the rest of the body,
f Superior cava returning blood from the head, forelimbs, and

dorsal integument chiefly.

Pulmonary veins returning blood from the lungs.
Vena portoe returning blood from the stomach, intestine, spleen
PRINCIPAL VENOUS TRUNKS -( and pancreas to liver.

Anterior abdominal returning blood from the urinary bladder

and belly-walls to liver.

Inferior cava returning blood from the hind-limbs, kidneys, and
liver chiefly.

DIAG11AM II. TRUNCUS AETERIOSUS laid open to show action of heart —

Pylangium (Gr. pule, gate ; angeion, a vessel), or receiving part, contains a median longitudinal
valve or movable partition attached to the dorsal surface, and a small transverse valve on the
right side.
Synangium (Gr. sun, together), or distributing terminal part, gives rise to Pulmo-cutaneous, Aortic,

and Carotid trunks.
FIGS. 3, 4. CIRCULATION OF THE BLOOD IN THE WEB —

Arteries with flow of blood towards the smaller branches.

Capillaries arising from the ultimate branches of the arteries and giving rise to the veins.
Veins with flow of blood from smaller to larger vessels.
Oval blood-corpuscles coursing through the vessels.
Pigment-cells on the surface
RESPIRATORY SYSTEM —

FIGS. 5, 6. STRUCTURE AND FRAMEWORK of the Respiratory Organs —

FIG. 5. Glottis (Gr. glotta, the tongue), a longitudinal slit opening into the floor of the back part

of the mouth or pharynx (PL XVIII. Fig. 3).

Arytenoid cartilages, one on each side of the glottis, movable inwards and outwards.
Laryngo-tracheal cartilage, a ring forming the very short tube common to the two lungs.
FIG. 6. The Lung is a thin-walled, elastic, and transparent bag, the inner surface of which
shows shallow depressions produced by infoldings of the wall, and corresponding to the air-
cells of higher animals.
FIG. 7. MUSCLES of the throat for depressing and raising the floor of the mouth — inspiratory muscles.

/ Mylo-hyoid (Gr. mule, a mill), insertion in rami of mandible.
MUSCLES HAVING THEIR I „.•?.,. .- • i • r j-n i-

i Gemo-hyoid, insertion in symphysis 01 mandible or coin.
"ORIGIN IN ANTERIOR < TT , , ., . . ,.

J Hyo-glossus (Gr. c/lossa, the tongue), insertion m tongue.
PORTION OF HYOID . . I T.* °, ., . i. .

\ Petro-hyoid, insertion in auditory capsule.

MUSCLES HAVING THEIR "IN- "} ,-. , ., /ri ., , ,, \ ... ,

I Omo-hyoid (Gr. omos, the shoulder), origin m scapula.

SERTION IN POSTERIOR > o, , . , ...

1 bterno-hyoid, orism in sternum.
PORTION OP HYOID . . )

NOTE. — The point of attachment comparatively flxeil is called the Origin of the Muscle, while the attachment to the part to be
moved is called its Insertion.

EDIBLE FROG(RANA ESCULENTA)— CONT°-

PLATE .

* I 4- I . Brain - &>rjiil

Qiag.l. .
Fig 4 Brmn I fynal a*rt OlfyjLtoy su

Crrfbro spvial f-sy
vatt/nl

-2. Lang1. vr/Hrnl tun h, in ,tf,1it>n

')27T7U7,7 Gtjrd,

Dieg 2. Transverse Stttion , rffyuwl Cord * SturaL (jm*<

mater amru] i
AmchnoiiL inembrtxnt

mater investing Spaial Card

^ .3 Sfrvf« yovifl to Musctf.r at'tht Eye,

Antzricn' (n- Vtnti-ul fissure

flap ShufltJ of T

Fi6. 7 Jitfitrftfiai

Thft/h- «fc Lea ffiruf Limb

" ' •- 9 Antfrtfr or f-rorrt

i^. 9
on. (he fcnt of the faffr 'pattern* *urtot

W tAK.lohn-wn EdifaVur^i t Londoi

41

PLATE XXI.
iTITTTn i|i [_> f~\(~V .• 7

\ t~\ Pi J? JTuV-lvT continued.

NERVOUS SYSTEM —

FIGS. 1, 2. THE BRAIN or ENCEPH'ALON (Gr. en, in ; kepha.lt>, the head) —

'Olfactory lobes or Khinenceph'alon (Gr. rhis, rhinot, the nose) giving oil

olfactory nerves.

, Cerebral hemispheres or Prosenceph'alon (Gr. pros, before) completely
OHE-BIIAIN ^ separated by the great fissure (fig. 3).

I Optic thalami ((!r. thalamns, a bed), one on each side bounding the third

ventricle with pineal gland on roof.=Thalaiiionceph'alon.

Mii>BuAiN f Optic lobes above and crura cercbri (L. legs of the cerebrum) below. =
(Yellow) ( Mesenceph'alon (Gr. meson, middle).

/Cerebellum (L. the little brain), very small = Metenceph'alon (Gr. ultta,
3 behind).

) Medulla oblongata (L. elongated marrow) with the fourth ventricle. =
V Myelonceph'alon ((Jr. muelos, marrow).

Lamina terminalis (L. terminal plate), the anterior wall of the thalamencephalon ter
minating the axial portion of the brain, the hemispheres being lateral expansions.
FIG. 3. THE CAVITIES OF THE BRAIN, so-called Ventricles —

1. Olfactory.

2. Lateral . )

o n,i • j • , Aperture of communication, foramen of Munro.

3. llurd ventricle j

Iter a tertio ad quartum ventriculum (L. passage from third to fourth ventricle), with
ventricles of optic lobes entering it.

4. Fourth ventricle, continuous with central canal of spinal cord.

Fio. 4. GENERAL VIEW OP THE BRAIN AND SPINAL CORD, cerebro-spinal axis —

Brain showing chiasma (Gr. a crossing) of the optic nerves, and optic tracts leading from optic

lobes.

Spinal cord or myelon, tapering away to the filum tenninale (L. terminal thread).
DIAG. 1. Teu pair of CRANIAL NERVES, ten pair of SPINAL NERVES, and ten pair of SYMPATHETIC

GANGLIA —
CRANIAL NERVES, 1 to 10 (yellow).

Spinal 1, hypoglossal (Gr. Jmpo, under ; ;/lvssa, a tongue), distributed to

tongue.

,, 2 and 3, forming a brachial plexus (L. brachium, an arm ; plexus,
a junction), and distributed to fore-limbs.

SPINAL NERVES
(Blue)

/ ,, 4, 6, and G, distributed to the body-walls.

„ 7, 8, and 9, forming a lumbo-sacral plexus (L. lumlns, the loin).

and distributed to posterior portion of body and hind-limbs ;
crural to front of limb and sciatic (contraction for ischiatic)
to back of it.

10, distributed to parts about coccyx.
SYMPATHETIC GANGLIA (S. 1 to S. 10), with connecting commissures (red).
DIAG. 2. CONTENTS OF NEURAL CANAL, as seen in a transverse section —

rGrey matter, a central square with its four corners passing into the

posterior (dorsal) and anterior (ventral) roots of the nerve-trunk.
SPINAL COUD -\ Central canal lined with epithelium.

»,., ., .., ( Posterior fissure (dorsal).

\\ hite matter outside grey matter J
L. ( Anterior fissure (ventral).

f

42

fPia mater, a vascular membrane investing cord and continuous with
MEMBRANES LINING I Dura mater Hning canal ^

| Arachnoid superficial to pia mater and dura mater, and secreting arachnoid
VESTING CORD ,, . , ,, , N

I. fluid (blue).

FIG. 5 and DIAG. 3. CRANIAL NERVES, and their distribution —

I. Olfactory (L. oleo, I smell) distributed to olfactory sac, as shown in Diag. 1.
II. Optic distributed to eye (Diag. 3).

III. Oculo-motor (L. oculus, eye ; motor, mover) distributed to four muscles of eye (Diag. 3).

IV. Pathetic distributed to superior oblique muscle (Diag. 3).
V. Trigeminal dilates into Gasserian ganglion giving off —

V1. Orbito-nasal or ophthalmic distributed chiefly to the nasal chamber.
V2. Superior maxillary distributed to upper jaw.

V3. Inferior maxillary or mandibular distributed to lower jaw or mandible.
VI. Abducens (L. abduco, I draw away) distributed to external rectus muscle (Diag. 3).
VII. Facial or portio dura (blue) dividing at Gasserian ganglion into —
VII". Or anterior distributed chiefly to the palate.
VIP. Or posterior dividing into a branch to the hyoid and a branch to mandible by way

of tympanic cavity = chorda tympani (L. cord of the drum).
VIII. Auditory or portio mollis distributed to the auditory capsule (Diag. 1).
IX. Glossopharynge'al (Gr. glossa, the tongue ; pJ/arunx, the throat) distributed to tongue and

pharynx (yellow).

X. Pneumogastric (Gr. pneianon, the lungs; gaster, the stomach) or Vagus (L. wandering) (red) —
X1. Cutaneous branch distributed to dorsal integument.
X-. Cardiac branch distributed to heart.
X3. Laryngeal branch distributed to larynx.
X4. Pulmouic branch distributed to lungs.
X5. Gastric branch distributed to gullet and stomach.

FIG. G. XEUVES OP HIND-LIMB, bones displaced to show nerves of dorsal surface —

o / Perone'al (Gr. perone, the fibula) running beside peroneus muscle.

( Posterior tibial running beside tibialis posticus muscle.
MUSCULAR SYSTEM —

DIAG. 3. MUSCLES OF EYE.

Fiu. 7. SUPERFICIAL MUSCLES OF HIND-LIMB. Frog dissected when laid on back, with dorsal surface of

foot uppermost.

Name.
Adductores — brevis, magnus, and

longus.
Sartorius.

TUIGII

LEG i

Rectus interims major,
llectus internus minor.
Vastus internus.

( Gastrocnemius, the bulk of the calf of the leg
(Gr. gaster, the belly; kneme, the leg).
Tibialis posticus (L. posterior tibial).
Perone'us.
Tibialis anticus (L. anterior tibial).

Extensor cruris brefis (L. short extender of

the leg).
Flexor tarsi anterior (L. anterior bender of

the tarsus).

Pubis.

Pubis.

Pelvis.
Pelvis, near to

hip-joint.
Partly femur,

partly cms.
Crus.
Femur.
Femur.

Femur.
Femur.

Insertion.
Femur.

Crus, inner side of

knee-joint.

Do.

Do.

Do.

Ending in tendo

Achillis.
Astragalus.
Calcaneum.
Astragalus and

calcaneum.
Crus.

Astragalus.

43

Name. Origin.

Fi». 8. DEEP MUSCLES on front or ventral surface of thigh —

Pectin'eus. Pelvis.

Adductor brovis, also seen on surface.
Semitendinosus. Pelvis.

Vastus intemus, also seen on surface.

Fio. 9. MUSCLES on back of thigh — for dissection lay out as in PI. XVIII. fig. 1

C Vastus internus. ""I

Triceps femoris (L. triceps,} 1!cctus femoris

having three heads) *ntlcus Mf Pelvia

shown).

L Vastus extcrnus.J

Glutae'us (Gr. gloutos, the buttock). Pelvis.

Pyriformis. Urostyle.

Biceps feraoris (L. biceps, having two heads). Pelvis.

Semimembranosus. Pelvis.

Roctus interims, seen also on front.

Insertion.
Femur.
Crus.

C'rua.

Femur.

Femur.

Fumur.

Crus and femur,

round knee-joint.

EDIBLE FROG (RANA ESCULENTA)— CONT"-

PLATE XXII.

Fi d. 5 Eaj~~bones of Jiioitaii J£iu~
a

of Kye, oC

seen >thim. behnuL c Fastener half -seen, fro

Fi6 Z Auditory- region - side, view rfitttonwl part,.

* <-'

Fij.8 Renal £ Rejjroduciwf. aj^

A O Cnj \ Fig 10 Sectwn.jrf_Uruulmnu! Tubule.

°

Fift-15 TadpoU further aavafu

W tAK. Johnston. Edinburgh I Londoi

45

PLATE XXII.

FROGr continued.

SENSE GROANS —

FIG. 1. EVE OF Ox divided — (ft) Into a right and left half — left half shown.

(6, r) Along equator into an anterior and posterior half.
Sclerotic or outer coat passing into transparent cornea in front.

Choroid coat pigmentcd, anterior end raised into longitudinal plaits — the ciliary processes.
Iris (L. a rainbow), anterior to ciliary processes, and connected to sclerotic where it passes into

cornea by the ciliary muscle.
Lens enclosed in capsule, which is attached to the inner side of the choroid by mspemnry

ligament.

Ciliary muscle dips into folds of ciliary processes above, just as suspensory ligament dips into them below (4).
Aqueous humour anterior to lens.
Vitreous humour posterior to lens.
Retina inside choroid.

Optic nerve entering a little to one side of axis by the optic pore.
FIG. 1 c. Blood-vessels are seen to enter retina from the spot where optic nerve enters.
FIG. 2. GENERAL VIEW OF RIGHT EAR or FROG —

Tympanic cavity exposed by removing tympanic membrane.
Three semicircular canals.
Columella auris (L. little column of the ear).
FIG. 3. MEMBRANOUS LABYRINTH OP LEFT EAR —

Semicircular canals, anterior, posterior, and horizontal, each dilated at one end into ampullae
(L. ampullor, I swell out), and two ends of vertical canals joining together.

( Utriculus (L. a little bag), into which semicircular canals open.
Vestibule.

JU;
3 (Be

Sacculus (L. a small bag).
Cochlea (L. a snail's shell), rudimentary.
FIG. 4. ESSENTIAL PARTS OF HUMAN EAR, natural size —

External ear — Pinna or concha (L. a shell), not shown.
Auditory meatus (L. a cnnal).
Tympanic membrane.
Tympanic cavity or tympanum opening by Eustachian tube into pharynx.

( Malleus (L. a hammer).

Middle ear

Auditory ossicles or ear-bones bridging over cavity J. Incus (L. an anvil).

1 ,_ _ . _ ,-

V. Stapes (L. a stirrup).
Fenes'tra ovalis (L. oval window), an oval membrane, to which foot-plate of

stapes is attached.
Fenestra rotunda (L. round window), at the base of cochlea.

( Semicircular canals, horizontal not shown.
Internal ear or 1 Tr ,., , . , , . ,

1 b ' tl i Vestibule into which canals open.

(. Cochlea, also communicating with vestibule.
FIG. 5. AUDITORY OSSICLES OF HUMAN EAR, magnified.
FIG. 6. COLUMELLA AURIS detached (see also fig. 2) —

Stapes or inner end fits into fenestra ovalis.

Extra-stapedial or outer end attached to tympanic membrane.

46

REN AT, AND REPRODUCTIVE ORGANS —

FIG. 7. MALE ORGANS from the ventral surface. The right tcstis is turned over to show its efferent

ducts —

Testes on the ventral side of kidneys.

Yasa effcrentia (L. afferent vessels), leading to inner side of kidney.
Kidneys in the dorsal part of abdominal cavity.
1 )uct passing from outer side of kidney to open into cloaca — Genito-urinary canal, because

it serves as ureter for the kidney and vas deferens for the testis.
FIG. 8. FEAIALE ORGANS removed from body —

Ovary much folded and distended with ova.

Oviduct distinct from ovary, anterior end opening beside gullet, posterior end in cloaca.
Ureter slender and opening into cloaca, posteriorly to oviduct.
Openings into cloaca — Rectum.

Urinary bladder, on ventral side of rectum independent of ureter.
Oviduct, anterior to opening of ureter.
Ureter.
FIGS. 9, 10. MALPIGHIAN CAPSULE OF HUMAN KIDNEY —

Tubule with its rounded dilatation, the Malpighian capsule.

Glomer'ulus (L. a ball), the tuft of looped capillaries formed by afferent vessel from renal
artery, and uniting again to form an efferent vessel (vein), which breaks up into capil
laries on the wall of the tubule.
Epithelium of capsule, glomerulus, and tubule.
FIG. 11. MALPIGHIAN CAPSULE OF FROG'S KIDNEY —

Epithelium lining tubule, with cilia to expel the urine.
FIG. 12. OVUM AND SPERMATOZOON OF COMMON FROG —
Spermatozoon with vibratile tail.

Tadpole or Larval Frog at different Stages.

FIGS. 13, 14. EXTERNAL BRANCHIAE, three on each side of neck.

Suckers, dilatations of the integument secreting a sticky substance.
Horny jaws.

Operculum or gill-cover beginning to form.
FIG. 15. OPERCULUM grown over gills, leaving only a small opening on left side for some time.

Hind-limbs appearing at first as tubercles, fore-limbs hidden by operculum.
FIG. 16. HEAD OF VERY YOUNG TADPOLE, magnified —
Visceral clefts, six on each side of neck.
External branchiae, two on each side of neck (a third pair afterwards developed

EDIBLE FROG(RANA ESCULENTA)— CONT--

PLATE XXIII.

frog's Eggt - natural six*

Fi£.2. Process of Yelk division, of 'impregnated egg

c x'Tx /?

. aJkr patiring thrvugh Oviduct

b. C0]£tmnay-mitj&- surface- of ^> CiHaietL

Vertical sfxtuni. of

fff Frog

Oiag. 2 Feriica2 Section of' KpUhfliurn o

/ tide- vinv

Connec&vf-- Tiatut -.

C> Ytttow elastic,
ligament* between, the. -vertebra*

Fi ^. 8 . Cartilagt'
famv tip of breast bow of' Frog *

"W A A K Jrfm«u,n. Eawiburgh. L L

47

PLATE XXIII.

THE FROG— continued.
DEVELOPMENT —

FIG. 1. EGOS, natural size (see PI. XXII. fig. 12, Egg magnified)—

a. Ovarian ova.

b. Laid eggs, surrounded by successive layers of albumen or white of egg secreted by the oviduct

and swelling up iu water.
FIG. 2. IMPREGNATED EGG showing successive stages in the process of yelk-division —

The immediate result of this process is the formation of a niorula (/), which by the soaking in

of fluid into its interior becomes a hollow sphere.
DIAG. 1. DEVELOPMENT OF TADPOLE —

( Outer layer or epiblast.
e 4 Mic

a. Blastoderm or germinal membrane •< Middle layer or mesoblast.

\ Inner layer or hypoblast (blue).
Medullary groove, a median longitudinal depression.
Lamiuaj dorsales (L. dorsal plates) or medullary folds, the epiblast raised up into folds on

each side of medullary groove.

Notochord or chorda dorsalis, the primitive axial column.

d. Neural canal formed by the union of the dorsal lamina;, with neural arcke<> in its walls.
Centra of spinal column invest notochord, which persists both in the centres of the bodies

of the vertebrae and in the urostyle.
/. Spirally-coiled intestine.
Large muscular tail.

Chief phases in life of Tadpole shown in PI. XXII.
FIG. 3. Perfect Frog, tailless, in natural position.
CLASSIFICATION —

Sub-Kingdom — Vertebrata, because it possesses a vertebral column ; limbs with an internal

skeleton ; and a portal vein with a capillary network at both its ends, receiving the

capillaries of the alimentary canal, and distributing to the capillaries of the liver.

Glass — Amphibia (Gr. amphi, both ; bios, life), because as a Tadpole it has gills, afterwards

lungs ; two condyles on the skull for articulation with the vertebral column ; and a cloaca.

Natural Orrlei — Anou'ra (Gr. «, without ; oura, a tail), because devoid of tail and gills in

adult life.
Genus — Ivaua.
Gommm Name — Frog.

Comparative Histology of Frog and Man.

FIGS. 4, 4a. BLOOD-CORPUSCLES —

( Frog — large, oval, and nucleated.

( Humau — smaller, round, and non-nucleated.
Colourless, like amoebae (see PI. IX. fig. 4).
FIGS. 5, 5a. EPITHELIUM (Gr. epi, upon ; thallo, I grow) in its principal varieties —

a. Squamous (L. squama, a scale) or scaly.

b. Columnar or cylindrical.

c. Ciliated.

Spheroidal or glandular (see PI. XXII. fig. 11).
FIG. G. a, b, c. CONNECTIVE TISSUE in its two principal varieties —

( Connective-tissue corpuscles, nucleated cells.
WHITE FIBROUS TISSUE .

( Matrix, fibrous.

YELLOW ELASTIC TISSUK, resisting acetic acid.

FIG. 7 and DIAG. 2. VERTICAL SECTION OF EPIDERMIS OR EPITHELIUM.
FIG. 8. a, b. CARTILAGE or GRISTLE —

( Matrix, granular.

( Cartilage cells, nucleated.

EDIBLE FROG(RANA ESCULENTA)— CONT»-

PLATE XXIV.

Fig. I Tran-yvtr»< Seftion, of ftwuir of F

Fig 3. Long1' section, of ffiuruin f'frtinr-

\ I

Fig. 6 Sirred- rtttmansnauclt

Fi g. 13 ITervou* & tanner Jive, dement* of Eye, ofTrog

Epidtrmjj

Wl*.K.JolmmMn, Elnburik ILondoa

40
PLATE XXIV.

I H Hi Jj jAiOvJI continued.

COMPARATIVE HISTOLOGY OF FROG AND MAN- — continued.
FIG. 1. TRANSVERSE SECTION OF FROG'S FEMUR-

Perios'teum (Gr. peri, around ; ofteon, a bone), the investing sheath of connective tissue.
Osteoblast layer (Gr. blastos, a germ), connective-tissue corpuscles arranged in a layer.
Bone-cells derived from osteoblasts.
Concentric lamellae of bony substance.

FIGS. 2, 3, 4. TRANSVERSE AND LONGITUDINAL SECTIONS OF HARD COMPACT TISSUE OF HUMAN HUMERUS -
Haversian canals for blood-vessels to run through, seen branching in fig. 3.
Concentric lamella) of bone round each Haversian canal.
Lacunae (L. hollows), oval spaces containing bone-cells (fig. 4).

Caualiculi (L. little canals), very minute tubes connecting the lacunse with one another.
FIGS. 5, 6, 7. MUSCULAR TISSUE —

FIG. 5. a, I. STRIATED OR STRIPED MUSCLE OF FROG taken from thigh-

( Sarcolemma (Gr. sarx, flesh ; l^mma, a sheath), the enveloping structureless

sheath (not shown).

1 Fibrilhe, the fibrils composing the fibre.
\ Nuclei, brought out by acetic acid.
FIG. 6. STRIPED HUMAN MUSCLE.

Fibre dividing longitudinally into fibrillte and transversely into disks.
Fia. 7. SMOOTH OR UNSTRIPED MUSCULAR FIBRES FROM HUMAN ARTERIES —

Individual fibre-cells with elongated nucleus.
FIGS. 8, 9. NERVOUS TISSUE-
FIG. 8 a, b. NEKVE-FIBRES —

( Primitive sheath, the investing structureless membrane.
NERVE-FIBRE . J Medullary sheath or white substance of Schwann.

' Axis-cylinder, the central part, fihrillated at origin and termination.
FIG. 9. NERVE-CELLS —

Granular protoplasm, nucleus and nucleolus.

Processes or poles sometimes branched and continuous with axis cylinders of nerve-fibres.
FIG. 10. LIVER —

Hepatic or liver cells with nuclei.

Blood-capillaries in section, from the blood of which the cells secrete or strain off the bile.
Bile-capillaries, minute passages shown as swellings between the cells.
FIG. 1 1 . EPIDERMIS OF FROG, surface view.
FIG. 12. VERTICAL SECTION OF SKIN OF FROG —

EPIDERMIS . . . Cells flattened and hardened towards the surface, plump and soft deeper

down where produced.

( Connective tissue, both varieties (PI. XXIII. fig. 6).
DERMIS OR TRUE J Pigment-cells = connective-tissue corpuscles containing pigment.

SKIN y Cutaneous glands, flask-shaped, lined by epidermis, aud opening on tlie

V. surface.
FIG. 13. NERVOUS AND CONNECTIVE ELEMENTS OF RETINA OF FROG —

(Connective tissue holding the nervous elements together, and extending from
external limiting membrane at the base of the rods and cones to internal

CONNECTIVE

^ limiting membrane in contact with vitreous humour.
\

Fibres of Muller, probably connecting the two limiting membranes.
NERVOUS . . . Bod and cone layer projecting beyond connective tissue, and embedded in

choroid.
FIG. 14. EPITHELIUM FROM NASAL CHAMBER —

Epithelial cells, columnar, with outer ends broad and inner ends attenuated and branched.
Olfactory cells, between epithelial cells, with fine hairs (Frog) or small rods (Man) on outer fine
process, and inner probably coming into connection with olfactory nerve, hence the name.

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