UNIV.OF
TORONTO
LIBRARY

AN ATLAS

OF

PRACTICAL ELEMENTARY BIOLOGY.

AN

ATLAS

OF

PRACTICAL ELEMENTARY

BIOLOGY

BY

HOWES,

0KMOX8TRATOR OF BlOLOOT, NORMAL SCHOOL OK SciKXCK AXU BuVAL SCHOOf, OK MlXKS. LECTURKR OX COMPARATIVE ANATOMY,

ST. GEORUE'S HOSPITAL MKDICAL SCHOOL, lasoos.

WITH A PREFACE

BY

PROFESSOR HUXLEY, P.R.S.

MACMILLAN AND CO.,

1885.

H

PRINTED BY

WEST, NEWMAN, AND CO.,
HATTOW GARDEN, LONDON.

TO

A. H.,

FRIEND AND ADVISER,

THIS WORK IS DEDICATED

BY
THE AUTHOR.

AUTHOR'S PREFACE.

THIS work has been designed with a view of furnishing the beginner with an evenly
balanced series of drawings, illustrative of the typical facts in the structure of living
things. The types chosen are for the most part identical with those adopted in Huxley
and Martin's "Elementary Biology."

The information imparted by a competent teacher ought to receive ample illustration
at his hands, and while it is hoped that this book may be of service to the student thus
happily placed, in producing it the author has been especially mindful of the less
fortunate inquirer, compelled to work unaided in a field beset with snares and pitfalls,
and byways which lead only to a laborious idleness.

An extensive and fully illustrated literature is within reach of the student, when
once he has acquired that method which can alone enable him to use it rightly; and
where this is the case for the organisms here dealt with, attempts have been made to
supplement it as far as possible.

All the figures are drawn, unless otherwise stated, from preparations made specially
with a view to the capacity of this work, and the plates are arranged in that order in
which it is most desirable the beginner should work them over. The paper used in
printing will take colour, provided the ordinary precautions are observed to avoid going
over the same surface twice while wet.

The text is confined exclusively to a description of the precise manner in which
each preparation was made, and as a number of valuable papers on many of the

Vlll

PREFACE.

subjects dealt with have appeared since the publication of our current zoological text-
books, I append a bibliography of them, together with certain classical monographs
indispensable to those desirous of extending either their own knowledge, or that of their
fellows, in the matter concerned.

The titles of the above-named works are arranged under heads and numbered for
purposes of reference in the text.

In preparing this work, it has been my good fortune to have had the counsel of
Professor HUXLEY, and I have to acknowledge my indebtedness to Professors T. J.
PABKEB and E. K. LANKESTEK, and to Mr. F. 0. BOWEK. My friend Mr. M. M. TEBBEBO
and certain of my pupils have rendered me welcome aid in the matter of cutting
sections, and my thanks are due to my lithographer, Mr. M. P. PABKEB, for the able
manner in which he has carried out my wishes.

NORMAL SCHOOL OF SCIENCE AND ROYAL SCHOOL OF MINES,
SOUTH KENSINGTON, February, 1885.

GEO. BOND HOWES.

PREFACE.

WHEN, in the year 1872, the system of practical instruction, which is at present
pursued in the Biological Laboratory of the Normal School of Science and Eoyal School of
Mines, was established, one of my first cares was the creation of a teaching collection
for the use of the students who were following that course of instruction. This
collection was to contain, in the first place, a series of preparations and dissections illustra-
tive of every important fact in the structure of the animals and plants selected for study ;
and, in the second place, a corresponding series of drawings of the dissections, of large size and
executed in such a manner as to facilitate the comprehension of the structures represented.

The construction of such a teaching collection as this lias involved the expenditure of
a great deal of time and skill ; and the whole burden of the work has fallen upon my former
demonstrator, Mr. T. J. PARKER (now Professor of Biology at Otago), and Mr. GEOBGE
HOWES, who succeeded Mr. PARKER, and now holds the office.

Ten years ago, assisted by Prof. MARTIN, I published "A Course of Practical Instruction
in Elementary Biology," which exemplifies the method of instruction pursued in the Bio-
logical Laboratory, and is intended to take the place of the oral instruction which we supply
there. The absence of illustrations, however, has greatly interfered with the usefulness of
this work, and I ain therefore very glad that Mr. HOWES has undertaken to make good the
defect by the publication of the present Atlas, which, while starting from part of the work
with which he lias been occupied in our Laboratory, contains so many accurate and well-
devised additional illustrations that it will be hardly less useful to students who are engaged
in the Laboratory than to those who work independently of it.

No doubt, the direct instruction of a teacher is very valuable ; but, with the aid of this
Atlas, I think that an intelligent student, who is unable to obtain that advantage, will
find no difficulty in working through " The Course of Practical Instruction in Elemen-
tary Biology " by himself.

T. H. HUXLEY.

SOUTH KENSINGTON,

April 24th, 1886,

CONTENTS

THE FROG (PLATES I. TO VII.) • PAGE 1

THE CRAYFISH (PLATES VIII. TO X.) ... ... 31

THE EARTHWORM (PLATES XL, XII.) ,,45

THE SNAIL (PLATES XIII., XIV.) ..... » 5S

THE MUSSEL (PLATES XV., XVI.) .... ,,61

THE HYDRA (PLATE XVII.)

THE UNICELLULAR ORGANISMS (PLATE XVIII.)

THE FUNGI (PLATE XIX.) . . T .

THE STONEWORTS (PLATE XX.) ....

QC

THE FERN (PLATES XXI., XXII.)

no

THE FLOWERING PLANT (PLATES XXIII., XXIV.) ..

APPENDIX AND BIBLIOGRAPHY ......

ERRATA.

a^e ,r)9, foot-note, for Sinnerepithelien read Bimie*epithelien.

„ 89, 1)8, and elsewhere, for protophlcem read protcmhloem.

., 108, for canula read cannula.

„ 110, middle paragraph, transpose the words "letter'1 and "numeral."

THE FROG

PLATES I. TO VII.

PLATE I

XIII

U :

MPFVriwrlilk

THE FROG.

PLATE I.

THE FKOG. — EXTERNAL CHARACTERS. THE GREAT CAVITIES OF THE BODY, AND THE
GENERAL DISPOSITION OF THE ORGANS CONTAINED THEREIN. THE MODE OF SUSPENSION
OF THE VISCERA.

Unless otherwise stated, all the figures of Plates I. to VII. refer to the Common Frog,
Rana temporaries.

FIG. I. — Head of Rana esculenta, 3, from above.
The vocal sac was inflated from the mouth.

FIG. II. — Head of Rana temporaria, 3, from the same aspect.
FIG. III. — The same, side view.

FIG. IV. — The left manus of Rana temporaria.
<?, Palmar surface.

FIG. V. — The same of the ? .

FIG. VI. — The left pes of Rana temporaria. Plantar surface.

FIG. VII. — The same of Rana esculenta.

(Figs. I. to VII. all natural size.)

FIG. VIII. — Dissection to show the general disposition of the viscera.

The skin, ventral muscles, and sternum were all removed, and the pericardium
opened up.

All the organs were left undisturbed, with the exception of the right lung ; in removing
the ventral muscles the anterior abdominal vein was dissected out, and the great veins of
the head and arm were removed on the right side,* to display the arterial arches and
adjacent glands. Nat. size.

FIG. IX. — General dissection, to show the boundaries of the body cavity, and the
mutual relations of those organs lodged within it, as seen from the left side (compare
Fig. VIII.)

The animal was pinned down through its hind linibs, those of the left side being
removed, the pleuro-peritoneal, buccal, nasal, and neural cavities were each opened up,
cutting well to one side of the middle line.

The dotted lines indicate the course of the oesophagus, i . x 2£.

Bee Appendix A.

•i ATLAS OF BIOLOGY.

FIGS. X., XI., XII. — Three sections, taken in order through the planes indicated by
the vertical lines in Fig. IX.

Figs. XI. & XII. are especially designed to show the mode of attachment of the
viscera, the reflections of the peritoneum being indicated by a thick line.

All are drawn as seen from behind, and the sub-cutaneous lymph-spaces, ly., are
indicated in black. <? . x 3.

FIG. XIII. — Dissection from the left side, to show the general disposition of the viscera,
and the neural canal with the cerebro-spinal axis.*

Proceeding as for Fig. IX., the mesentery was next removed along the line c.my'., and
with it the renal and reproductive organs of the left side — those of the right, together with
the lung of that side, being seen through the mesentery. The alimentary canal was pinned
down and the large intestine opened up ; the tongue is figured thrown forward in prehension.

The axial skeleton is here drawn in median longitudinal section. <? . * 2.

* See Appendix B.

ac.

ant.ab.

ao.

atr.

b.c.

b.d.

br.

A.w.

c.

ca.

cl.

d'.

c.my.

c.mg'.

CO.

cot.

cp.a.

d.ao.

e.l.
i'. HI.
e.n.
eu.
'J.l'l.

Acetabulum.

Anterior-abdominal vein.

Arch of Aorta.

Atrium.

Body cavity.

Bile duct.

Braiii.

Body wall.

Oalcar.

Carotid artery.

Cloaca.

Epidermal-lined portion of the same.

Sub-vertebral lymph sinus.

Its cut edge.

Rudimentary caecum.

Coaliaco-mesenteric artery.

Corpus adiposum.

Dorsal aorta.

So-called diaphragm.

Duodenum.

Eye.

Eye lids.

Eye muscles.

External nostril.

Eustachian recess.

Gall bladder.

i/l. Glottis.

h. Heart.

ky. Hyoid cartilage.

i. Ileum.

U. Ilium.

i.n. Internal nostril.

K. Right kidney.

k". Left kidney.

/.//. Levator bulbi muscle.

ly'. Right lung.

Ig". Left lung.

Lint. Large intestine.

to'. Right lobe of liver.

to*. Left lobe of liver.

ly. Sub-cutaneous lymph-spaces.

Inc. Larynx.

in. Mouth.

m.hij. Mylo-hyoid muscle.

inn. Mandible.

ins. Mesentery (dorsal mesentery).

in-s'. Ventral mesentery.

m.ty. Membraua tympani.

»UK. Maxilla.

my. Myelon.

na. Nasal sac.

n.(_ Neural canal.

THE FROG.

n.*ft. Spinal nerves.

«.»y. Sympathetic nerves.

ut. (Esophagus.

p. Pancreas.

pc. Cut edge of pericardium.

p.cu. Pulmo cutaneous artery.

jir.c. Vena cava superior (precaval vein).

pt. Peritoneum.

pt.e. Vena cava inferior (postcaval vein).

r. Rectum.

x. Sternum.

x.i,it. Small intestine.

».tc. Supra scapula.

*A. Skull.

sp. Spleen.

xt. Stomach.

t. Tongue.

lit. Thyroid gland.

tin. Thymus glaud.

t». Testis.

u.bl. So-called urinary bladder.

//./•/'. Orifice of the same.

in-. Genito-urinary duct <?.

ur1. Orifice of the same.

tut. Urostyle.

c. Ventricle.

v.c. Vertebral column.

e.x. Vocal sac.

t. to r. Digits i. to v.

THE FROG.

PLATE II.

THE FROG-.— THE ALIMENTARY, RESPIRATORY, AND UBINO-GENITAL ORGANS. THE HEART.

THE LYMPH-HEARTS, ETC.

FIG. I. — The entire alimentary apparatus, after removal from the body, dissected from
the ventral aspect.

The lower jaw was pinned back, and the interior of the right vocal sac exposed ; the
stomach, duodenum, cloaca, and bladder were each opened up. $. x 2.

The bile-ducts can readily be demonstrated, by gently squeezing the gall-bladder and
thus forcing the bile into them. For a full description, with figures, of the smaller hepatic
ducts and of the valve-like arrangement of the lining membrane of the small intestine, in
Rana esculenta, see Wiedersheim and Ecker (24).

FIG. II. — A portion of Fig. I., after removal of the liver, x 1£.

The lymph-sinus drawn can be readily inflated by introducing a blow-pipe under the
peritoneum.

FIG. III. — The respiratory segment of Fig. I.

The right lung was opened up, to show its internal structure, x !£.

FIG. IV. — The left lung of the same, with the larynx seen from the side.

FIG. V. — The same, after removal of the left lung together with one half of the larynx.

FIG. VI. — The cartilages of the larynx dissected out.
Seen from the front. All x li.

FIGS. VII. and VIII.— The lymph-hearts, x 1±.

The posterior one, Fig. VIII., is to be seen on removing the skin of the back, imme-
diately after death, and the anterior one by making a clean cut along the ventral body-
wall — to one side of the middle line — and a similar one into the cisterna magna, turning the
stomach to one side as indicated. Only such parts are drawn as are indispensable in
determining the positions of these delicate organs.

Certain details, as to the connections of the above with the great veins, are figured by
Ranvier (19).

. IX. — The heart, after removal from the body.
Seen from the front, the aortic arches of the left side having been removed, x 4.

FIG. X. — The same from behind, the sinus venosus having been opened up, to show
the sinu- auricular valves. x 4.

8 ATLAS OF BIOLOGY.

FIG. XI.— The same, dissected from the front, the ventral wall together with one of the
aurieulo-ventricular valves having been removed, x 6.

The rod, passed from the ventricle into the pylangium, indicates the course taken by
the blood which flows into the carotid and aortic trunks.

The most recent contribution to the anatomy of the smaller valves of the amphibian
heart is that of Boas (2).

FIG. XII. — Dissection of the same, from the left side, all the great cavities opened
up. x 4.

From nature, after Huxley's figure for Eana esculenta (11).

In preparing the heart from which Figs. IX. to XI. are drawn, the body-cavity of a
large frog was laid open, and the whole contents hardened in alcohol* undisturbed. On
removing the heart for dissection, the lungs, kidneys, and a portion of the gullet were
brought away with it, and finally removed piece by piece, as the great vessels were followed
out. By this means a heart, fully distended with its contained blood, may be easily
obtained.

FIG. XIII. — The urino-genital organs of the male, dissected from the front, after
removal from the body.

The cloaca and bladder were opened up. x 2.

The figure to the left represents the lower portion of the kidney and genito-urinary
duct in the 3 of Sana esculenta.

FIG. XIV. — The urino-genital organs of the female, dealt with in the same manner as
the above, except that, in order to show the natural relations of the mouth of the oviduct,
the left lung and a portion of the oesophagus were also removed from the body.

The genital gland of the right side has been dissected away, x 1 £.

^

* See Appendix C.

ail. Adrenal.

an. Arch of aorta.

ar. Arytenoid cartilage.

a.s. Inter-auricular septum.

an'. Right auricle.

au". Left auricle.

b.d. Common bile-duct.

l>.d'. Orifice of the same.

ra. Carotid trunk.

c.d. Cystic duct.

c.ffl. Carotid gland.

rl- Cloaca.

cl'. Epidermal-lined portion of the same

cp.a.

du.

fu.

fl.t.

ft.*.

h.d.

ky.

i.

il.

i.m.

same.

i.ii.

Corpus adiposum.

Duodenum.

Eustachian recess.

Fallopian tube.

Mouth of the same.

Gall-bladder.

Glottis.

Hepatic duct.

Hyoid bone.

Ileum.

Ilium.

Intrinsic muscles of lar\ nx.

Internal nostril.

.

THE FROG.

k. Kidney.

///'. Right lung.

/•/". Left lung.

/./t'. Anterior lymph-heart.

l.h". Posterior lymph-heart.

l.tr. Laryngo-tracheal cartilage.

lv'. Right lobe of liver.

/«". Left lobe of liver.

l.c. Larynx.

lij. CircumoDsophageal lymph-sinus.

m.o. Mesorchium.

m.ov. Mesoarium.

iiw. Mesentery.

mx.t. Maxillary teeth.

od. Oviduct.

od'. Its uterine portion.

od". Aperture of oviduct.

ic. (Esophagus.

ov. Left ovary.

/>. Pancreas.

/i. CM. Pulmo-cutaneous trunk.

l>.cu'. Point of origin of the same.

pf. Pyriformis muscle.

l>r. So-called vesiculae-seminales.

l>r'. Ducts of the same.

pr.c. Vena cava superior.

/>/.'•. Vena cava inferior.

p.v. Pulmonary vein.

p.v'. Aperture of entry of the same.

py. Pylangium. -

pyl. Pylorus.

r. Rectum.

s/). Spleen.

st. Stomach.

».v. Sinus venosus.

sy. Synangium.

t. Tongue.

tr. Truncns arteriosus.

Is. Testis.

".III. So-called urinary bladder.

«;•. Ureter ? . Genito-urinary duct <J .

ur'. Orifice of the same.

v. Ventricle.

v'. Cut edge of ventricle.

ea'. Auriculo-ventricular valve.

va". Sinu-anricular valve.

rn.l. Longitudinal valve (septum) of pylaugium.

v a.». Semi-lunar valves.

v.cd. Vocal cord.

v.ef. Efierent ducts of testis.

v.s. Vocal sac.

v.sf. Aperture of the left vocal sac.

r.t. Vomerine teeth.

I

PLATE III

... d-'.-ir...

THE FROG. 11

PLATE III.

THE FKOG.— THE BLOOD-VASCULAR SYSTEM.
(If necessary, this system can be readily injected. See Appendix D.)

FIG. I. — A dissection to show the large superficial veins.

The skin covering the ventral surface was reflected on the left side and the pectoral
muscles in part removed, as indicated by their cut edges. Nat. size.

FIG. II. — The musculo-cutaueous vein in Eana esculenta. Nat. size.

FIG. III. — General dissection of the blood-vessels from the right side.

The body-wall and arm of the right side were cut away, and the skin reflected. After
removal of the generative organs, the heart and liver were turned forwards, and sufficient of
the latter removed to show the whole course of the vena cava inferior and the hepatic veins.
The hind limb of the right side was retained, and the pelvic girdle h.g. removed, between
the cut ends indicated. This being done, the great veins of the head were dissected away,
in order to expose the aortic arches. x 2.

FIG. IV. — Dissection to show the anastomosis between the systemic (anterior-
abdominal) and portal venous systems.

The parts are all drawn as they lay, the heart and hinder portion of the left lobe of the
liver Iv." having been turned forwards, x 11.

FIG. V. — The arterial trunks, and their main branches, x li.

FIG. VI. — The venous trunks, and their main factors, x 11. Qee Appendix E.

FIG. VII. — A somewhat diagrammatic rendering of Fig. III., representing the entire
vascular system as seen from the left side, with all the great capillary systems indicated.
The arrows follow the course taken by the blood in life, x 2.

In all the figures of this plate, the vessels connected with the renal-portal system are
shaded darkly, the anterior abdominal vein included, while those carrying arterial blood are
left white.

a. Femoro-sciatic anastomosis. au". Left auricle.

"'. Abdominal-portal anastomosis. hr. Brachial vessel.*

ant.ab. Anterior-abdominal vein. c.e. Common-carotid artery.

«"'. Right aortic arch. c.tjl. Carotid gland.

ao". Left aortic arch. c.il. Common-iliac artery.

an'. Right auricle. ett. Coeliaco-mesenteric artery.

The references marked thus * apply to both arteries and veins, as the case may be.

12

ATLAS OF BIOLOGY.

cce'. Coeliac artery.

fp.a. Capillaries of anterior extremities.

cp.al. Capillaries of alimentary canal.

cp.cu. Cutaneous capillaries.

cp.hp. Hepatic capillaries.

cp.p. Capillaries of posterior extremities.

cp.pl. Pulmonary capillaries.

cp.rf. Renal capillaries.

cu. Cutaneous artery.

d.ao. Dorsal aorta.

(I.I. Dorso-Iumbar vein.

du. Duodenum.

du'. Duodenal vessel.*

e.j. External jugular vein.

fm. Femoral vein.

g. Gastric vessel.*

g.bl. Gall-bladder.

li, Haemorrhoidal vessel.*

h.g. Pelvic girdle.

hp. Hepatic vessels.*

hy. Hypogastric artery.

i.j. Internal jugular vein.

il. Ileum.

if. Heal vessels.*

in. Innominate vein.

/.•. Right kidney.

/. Lingual vessel.*

Iff. Right lung.

l(j". Left lung.

l.h'. Anterior lymph-heart.

l.h'1. Posterior lymph-heart.

Lint. Lieno-intestinal vein.

lv'. Right lobe of liver.

/»•". Left lobe of liver.

m.cu. Musculo-cntaneons vein.

m.liif. Mylo-hyoid muscle.

mn. Mesenteric artery.

od. Oviducal vein.

ov. Ovarian vein.

p. Portal vein.

pc. Pancreas.

pc'. Pancreatic artery.

p.cn. Pulmo-cutaneous artery.

pr.c. Vena cava superior (Precaval vein).

pt.c. Vena cava inferior (Postcaval vein).

pul. Pulmonary vein.

pul'. Pulmonary artery.

pv'. Right pelvic vein.

pv". Left pelvic vein.

r. Rectum.

r.fi. Rectus-abdominis muscle.

re. Renal vessels.*

r.p. Renal-portal vein.

»c. Sciatic vein.

sp. Splenic vessels.*

s.sc. Subscapular vein.

•it. Stomach,

s.r. Sinus venosus.

ir.a Truncus arteriosus.

ts. Spermatic artery.

?•. Ventricle.

r.r. Vertebral column.

vs. Vesical vein.

rt. Vertebral artery (printed as v. alone
Figs. III. & V.)

The references marked thus * apply to both arteries and veins, as the case may be.

THE FROG. 1»

PLATE IV.

THE FKOG. — THE SKELETON. THE MUSCLES OP THE HIND-LIMB.

JTIG- i. _ The entire axial skeleton, with the limb-girdles and the limbs of the right
side, drawn from above with the body in the resting attitude.*

Macerated preparation. x 1 1. The humerus and the metacarpal of the second digit
in the manus, drawn separately, are those of the male.

FIG. II. — The first vertebra, seen from the front.

FIG. III. — The fourth vertebra, seen from the same aspect.

FIG. IV. — The fifth and sixth vertebrae, from the side, in the natural position.

v. — The ninth (sacral) vertebra, seen from behind.
The articulations of the centra are shown in section in Fig. XIII., Plate I.

FIG. VI. — The shoulder-girdle, seen from the front, the left scapula having been
straightened out.

FIG. VII.— The left half of the hip-girdle, from the side.f

(Figs. II. to VII., all x li.)

FIG. VIII. — The skull (cranio-facial apparatus), after removal of the membrane bones
of the right side, seen from above.

The mandible and hyoid are excluded. Wet preparation. J

FIG. IX. — The same, seen from beneath.

In both this and the above, the membrane bones removed are drawn independently ;
in this figure, however, one half of the parasphenoid is indicated in situ.

FIG. X. — The same, seen from the side, with both mandible and hyoid in place.
FIG. XI.— Back view of Fig. VIII.

FIG. XII. — Sectional view of the above, exclusive of the hyoid. Meckel's cartilage has

been exposed.

(Figs. VIII. to XII., all x 2£.)

FIG. XIII. — The body of the hyoid, of a young frog, x 2.

(In all the above figures the cartilaginous parts are stippled.)

' The so-called calcar, r., is generally composed of two or more pieces, and represents the remnant of a xi&th diyii.
Compare Born, " Die sechste Zehe der Anuren," Morph. Jtihrh., vol. i., 1875 : Wiedersheiiu, " Lehrbuch der vergleichenden
Anatomie," Jena, 1888. See also Marsh, " The Limbs of Sauranodon," American Journal of Science and Arts,
vol. xix., 1880.

t The upper cartilaginous articular-end of the ilium miy be appropriately termed the xupra-iliniit.
£ See Appendix F.

14

ATLAS OF BIOLOGY.

FIG. XIV. — The muscles of the hind-limb, ventral aspect.

The superficial muscles are shown on the right side ; the sartorius was reflected, the
adductor-longus, adductor-magnus, and gastrocnemius were slightly displaced. On the left
side the sartorius was left uninjured ; it and the adductor-magnus were a little displaced
and the rectus-internus reflected, in order to render visible the semi-tendinosus.

FIG. XV. — The muscles of the hind-limb, dorsal aspect.

On the left side, the vastus externus, and on the right the biceps-femoris have been
reflected. The semi-membranosus and the head of the gastrocnemius of the right side were
displaced.

FIG. XVI. — The deep muscles inserted into the head of the femur.

Bight side from without.

The cut ends of the muscles removed are all shown.

(Figs. XIV. to XVI. x li. in ail the bones are stippled.)

ac. Acetabulum.

ad. Adductor magnns.
ad'. Adductor longus.
ad". Adductor brevis.
ar. Splenial.

as. Tibiale.

au. Periotic capsule.

b.f. Biceps femoris.

c. Calcar.

c.a. Columella auris.

ca. Fibulare.

cd. Occipital condyle.

cd'. Mandibular condyle.

el. Clavicle.

en. Vertebral centrum.

co. Coracoid.

cp. Carpus.

cr. Os cruris.

d. Dentary.
dl.c. Deltoid crest.

e.c. Extensor cruris brevis.

f.o. Exoccipital.

/. Femur.

fl>. Fibula.

fo.a. Anterior fontanelle.

fo.p. Posterior fontanelle.

f.ov. Fenestra ovalis.

f.pa. Fronto-parietal.

f.t. Flexor-tarsi anterius.

</. Glenoid cavity.

yl. Gluteus.

</s. Gastrocnemius.

</•«'. Outer head of the same.

7i. Humerus.

h.g. Hip-girdle.

It;/. Body of the hyoid.

/'//. Its anterior cornu.

/'//". Its posterior cornu (thyro-hyoid).

»'/. Ilium.

i.]>x. Ileo-psoas.

»'«./. Intervertebral foramen,

is. Ischium.

ll>. Labial cartilages.

m.cp. Metacarpus.

md.c. Medial crest.

mk. Meckel's cartilage.

m.mk. Mento-meckelian bone.

m.ts. Metatarsus.

ma-. Maxilla.

•nti. Nasal

11. a. Neural arch.

n.c. Neural canal.

n.p. Pre-nasal process.

n.p'. Ali-nasal process.

n.sp. Neural spine.

ob. Obturatorius.

XTV

•

. *d n-U

THE FROG.

15

or.p.

I'-

pc.
per.
ph.
pi.

pr.o.

pt.

ft.

py-
i-j-
'/"•/•

rd.

r.f.

rh.fi.

r.i.

r.i'.

t.

id.

sc.

s.sc.

sh.ij.

s.mb.

a. n.

ip.

Antorbital process.

Pubis.

Parasphenoid.

Pectineus.

Peroneus.

Phalanges.

Palatine.

Pre- maxilla.

Pro-otic.

Pterygoid bone.

Pterygoid cartilage.

Pyriformis.

Quadrato-jugal.

Quadratus femoris.

Radius.

Rectus femoris.

Rhinal process.

Rectus internus major.

Rectus internus minor.

Sacrum.

Bartering.

Scapnla.

Supra scapula.

Shoulder-girdle.

Somi-membrunosus.

Septnm HUM.

Suspensorium.

*p'. Its dorsal eras.

*p*. Its pedicle.

ip.e. Sphenethmoid. %

*'/. Squamosal.

st. Stapes.

xt'. Omosternum.

it". Xiphisternum.

s.t. Semitendinosus.

t.t'. Its union with the adductor magnus.

tb. Tibia.

Tibialis anticus.

Tibialis posticns.

tb.p'. Notch for the tendon of the above.

tr/. Triceps femoris.

tr.p. Transverse process.

to. Tarsus.

id. Ulna.

utt. Urostyle.

i'.f. Vertebral column.

e.ex. Yastus externus.

r.tn. Vastus internns.

vo. Vomer.

zy'. Anterior zygapophysis.

xtf. Posterior zygapophysis.

••. to '•. Digits i. to v.
/. to .V. Foramina of exit for cranial nerves I. to X.

THE FHix;

PLATE V.

THE FROG. — THE NERVOUS SYSTEM AND BRAIN, THE ANATOMY OF THE OLFACTORY,

VISUAL, AND AUDITORY ORGANS.

FIG. I. — The cerebro-spinal axis and the course of the fifth cranial nerve, displayed
from above.

The whole dorsal integument was removed, and the neural cavity opened up from
above ; on Ihe right side the nasal bone has been removed, and the eye dissected out. x 2.

FIG. II. — The cerebro-spiual axis, with the great nerve trunks — including the sympa-
thetic—dissected from the ventral aspect. The origins of all the cranial nerves except the
iv* are shown, and the sympathetic is indicated on one side for its whole length.

The entire ventral body-wall, together with the viscera and the floor of the mouth, were
removed. After carefully dissecting the aorta away from the sympathetic, that system was
removed on the left side. The whole neural canal was next laid open, by removal of the
vertebral centra and the floor of the skull ; the eye on the left side, the hinder portion of the
upper jaw on the right, and the floor of the auditory capsules of both sides, were dissected
away. The vn cranial, i spinal, and sympathetic nerves are all shaded darkly, x 2.

FIG. III. — The cranial nerves, irrespective of those connected with the olfactory,
visual, and auditory organs, together with the first five spinal nerves, and sufficient of the
sympathetic to show the origin of the splanchnic nerve.

The whole integument covering the head was removed, together with the eye and
hinder portion of the upper jaw with its associated parts ; the left arm and shoulder-girdle
were also removed. The body-cavity and the cisterna-magna were both opened up and the
spinal nerves n to v turned forwards, to render clear the relations of the sympathetic.
The vn cranial and sympathetic nerves are tinted as in Fig. II., and all the spinal nerves
are drawn in black, x 2.

FIG. IV. — The leading nerves of the hind limb, seen from the dorsal aspect.

The gastrocnemius, peroneus, and tibialis-anticus muscles have each been reflected, and
those of the upper segment of the limb pulled apart, sufficiently to display the nerves
drawn. Nat. size'.

FIG. V. — A transverse section, taken immediately behind the exit of the second spinal
nerve, to show the relations of the nerve roots and investing membranes, x 6.

FIG. VI. — The brain, seen from above in situ, before the removal of the pia mater.

* This is shown in Fig, VIII,

18 ATLAS OF BIOLOGY.

FIG. Yir.— Ventral aspect of the same, after removal from the body.*

FIG. VIII. — The same, seen from the left side.
The origin of the fourth cranial nerve is shown.

FIG. IX. — A dissection of the same from ahove, to show the ventricles.

The lateral and optic ventricles have been exposed on the right side, and the median
portion of the cerebellum removed. On the left side the whole system of cavities has been
laid bare to the level of the foramen of Monro, in order to show the relationships existing
between the axial and lateral portions of the brain.

FIG. X. — The lateral and optic ventricles, exposed from the left side.

FIG. XI. — Vertical longitudinal section of the entire brain, cut a little to one side of
the middle line.

Figs. VI. to XI. were drawn from brains preserved in alcohol. All x 3.

The stippled surfaces represent cut edges.

It is doubtful if the parts lettered ol. really represent the olfactory lobes, and the
morphology of the nervous tract connecting them has yet to be ascertained. It is also a
question if the body here termed pineal gland, p.gl., is the strict homologue of that of other
vertebrates. The latest researches iu this direction are those of Osborne (17A).

FIG. XII. — The right olfactory sac, opened up from without, along the line a — b of
Fig. XIII.

The elevation in its floor overlies the vomer, and the forward growth from the lower lip
of the anterior nostril is supported by the aliriasal cartilage. (n.p.1 Fig. VIII., PI. IV.)
x 4.

FIGS. XIII., XIV., XV. — Three figures of the eye-rnuscles and their nerves, the
nictitating membrane, and Harderian gland. All x 2|.

XIII. — Dorsal view.

The whole integument covering the head was removed, and the superior-rectua of the
left side reflected.

XIV. — Ventral view.

The mucous membrane of the roof of the mouth, and the levator-bulbi muscle of the
right side, were removed. A portion of the auditory capsule lias also been dissected away,
to expose the 6th nerve.

".— The same ; the inferior-oblique and recti muscles, and, on the left side, the outer
portion of the face, have all been removed.

FIG. XVI.— The eye, seen from without, in the living animal.

FIG. XVII.— Section of the left eye and eyelids, taken through the plane of the optic
nerve.

s The pituitary body is not nnfrequently produced into a pair of lateral expansions, thus becoming trilobed.

THE FROG.

19

FIG. XVIII. — The outer half of an eye, bisected at right angles to tho plaiie of the
optic nerve.

FIG. XIX. — The inner half of the same.

In both figures the internal surface is drawn. All x 31.

FIG. XX. — Transverse section of the head, immediately behind the occiput, especially
designed to show the relations of the auditory organ.

On the left side all structures, excluding the post auditory cranial nerves, have been
removed to the level of the columella auris and hind wall of the skull ; on the right the
auditory capsule has been opened up to the level of the vinth cranial nerve. x 3.

FIG. XXI. — The membrana tympani, seen from without.

The dotted lines indicate the course of the mucous membrane lining the Eustachiau
recess, and in both this and the preceding figure, the tympanic auuulus is indicated in
black, x 3.

FIG. XXII. — The membranous labyrinth of the left side, seen from without, after
removal from the body.

Holding the auditory capsule between the finger and thumb, the bone was sliced away
piecemeal with a small scalpel. x 6.

FIG. XXIII. — The same, seen from within, a portion of the auditory nerve having been
removed with it. x 6.

The structural details of this organ have recently been fully worked out by Ketzius, in
his classical monograph, "Das Gehororgan der Wirbelthiere," vol. i., Stockholm, 1881.
Figtircs reproduced in Wiedersheim and Ecker (24).

a.c. Anterior commissure.

am'. Ampulla of the anterior semicircular canal.

am''. Ampulla of the posterior semicircular canal.

am"'. Ainpulla of the horizontal semicircular

canal.

aij.c. Anterior (aqueous) chamber.

a</.s. Aqueduct of Sylvius (Iter).

a.s.c. Anterior-vertical semicircular canal.

at. First vertebra.

a.tij. Annulus tyrnpaiiicus.

ax. Auditory capsule.

b.jil. Brachial plexus.

b.n. Brachial enlargement,

c. Cornea.

c'. Commissure between 7th and Oth cranial

nerves.

c.u.

clt.

cd.

• •//.

c./i.

did.

cj.

'•./•/.

c.(//.

il./n.

du.

e.l.

el'.

Commissure between palatine and maxillary

nerves.

Columella auris.
Cerebellum.

Occipital condyle (tig. 111. cardiac nerve).
Optic chiasma.
Cerebral hemisphere.
Choroid.
Conjunctiva.
Choroid plexus.
Chorda tympaui.
Dura junior.
Duodenum.
Upper eyelid.
Lower eyelid.
Tendon of the same.

ATLAS OF BIOLOGY.

e.n. External nostril.

e.r. External rectus.

en. Eustacbian recess.

ex.d. Extensor digitorum muscle.

J'ni. Crural nerve.

/.in. Foramen of Monro.

f.tm. Filum terminale.

ij. Gastrocnemius.

!/.il. Ganglion of nerve-root.

ij». Gastric braneh of vagus.

(j.t. Gasserian ganglion.

y.vg. Ganglion of the trunk of vagus.

It.gl. Harderian gland.

hp. Hypoglossal (1st spinal) nerve.

h.s.c. Horizontal semicircular canal.

hy. Hyoid arch.

il. Ilium.

i.n. Internal nostril.

inf. Infindibulum.

in.r. Inferior rectus.

i.ob. Inferior oblique.

ir. Iris.

i.r. Internal reetus.

I. Crystalline lens.

lij. Laryngeal nerve.

l.s. Lumbo-sacral enlargement.

Ls.pl. Lumbo-sacral plexus.

l.tm. Lamina terminalis.

l.v. Lateral ventricle.

Iv.b. Levator bulbi muscle.

md. Medulla oblongata.

mn. Mandibular nerve.

m.ty. Membrana tympani.

mx. Maxillary nerve.

my. Myelon.

na. Nasal sac.

na'. Nasal bone.

n.c. Neural canal.

ol. " Olfactory lobe."

ol'. Ventricle of the same.

ol.n. Olfactory nerves.

o.i/a. Orbito-nasal nerve.

<>1>. Optic lobe

op'. Ventricle of the same.

p. Periosteum.

pc. Pancreas.

l>.c. Posterior commissure.

pe. Peroneus muscle.

p.tjl. " Pineal gland."

pi. Palatine nerve.

p.m. Pia mater.

p.n. Peroneal nerve.

ji.s.c. Posterior-vertical semicircular canal.

pt. Pterygoid muscle.

pt.b. Pituitary body.

pul. Pulmonary branch of vagus.

r. Retina.

r.b. Retractor bulbi muscle.

r.d. Dorsal ramus of glosso-pharyngoal nerve.

r.d'. Dorsal ramus of vagus.

s. Sacculus.

*c. Sciatic nerve.

scl. Sclerotic.

s.mb. Semimembranosus.

s.ob. Superior oblique.

sp.n. Splanchnic nerve.

s.r. Superior rectus.

st. Stomach.

ntji. Stapes.

*!!•!/• Sympathetic ganglion.

sy.n. Sympathetic nerve.

'. Tongue.

t.a. Tibialis anticus.

tb.n. Posterior tibial nerve.

tli. Thalamencephalon.

tr.f. Triceps femoris.

ut. Utriculus.

f. Vestibule.

«'. Diverticulum of the same.

v.c. Vitreous chamber.

v3. Third ventricle.

v4. Fourth ventricle.

TO. Vomer.

/. to X. Cranial nerves I. to X.

1 to 10. Spinal nerves 1 to 10.

THE FROG. 21

PLATE VI.

THE FKOG. — GENERAL HISTOLOGY (see Appendix G).

FIG. I. — Ciliated epithelium.

Scraped from the roof of the mouth of a recently killed frog.

Normal salt solution, afterwards stained with eosin. D. 3.

FIG. II. — Columnar epithelium.

Scraped from the lining membrane of the small intestine. Treated as for Fig. I., D. 3.

The four cells to the left retained their natural relationships, and in connection with
those numbered i and ii, the mucin secretion is indicated; ii is drawn in the act of
discharging the same.

FIG. III. — A portion of the Frog's mesentery, examined in water after two hours'
exposure to the sun's rays in silver nitrate solution D. 2.

FIG. IV. — i. A small piece of intermuscular connective tissue.

Spirit material, stained with borax carmine.

If no white fibres are readily visible, a piece of tendon should be teased up.

ii. Pigment cells (of the mesentery) in various stages of development. D. 4.

FIG. V. — Hyaline cartilage.

i. Thinnest part of the xiphisternum, after removal of its fibrous investment. Fresh, D.2.

ii. One group of cells of the above, more highly magnified. F. 4.

The nucleus of the uppermost cell has divided, prior to the division of the cell itself.

FIG. VI.— The fat-cell.

i. Section of the corpus adiposum. Alcohol and borax carmine. F. 3.

ii. Cells of the above, teased up fresh. Stained with eosiu. D. 3.

iii. A ripe fat-cell. The fat-drops have united to form one large globule.

For an account of the morphology of the corpus adiposum see Marshall (16) and
Bourne (3).

FIG. VII. — The blood, examined immediately after death. D. 4.

i. Three phases in the life of the same corpuscle, at successive intervals of two minutes
each.

ii. Phases in the union of two corpuscles.

iii. A late stage in the fission of a white corpuscle. F. 3.

At iv. are a number of red corpuscles seen on end.

FIG. VIII. — Transverse section of the spinal cord.

On the right side the pia mater is shown, and more especially the large multipolar
nerve-cells of the anterior cornu. A. 3.

Chromic Acid. Alcohol. Borax carmine.

22 ATLAS OF BIOLOGY.

FIG. IX. — Transverse section across the scia.tic nerve. Alcohol and hseinatoxylin. A. 3.
The sheath, p.n., is often laden with fat.

FIG. X.— A small portion of one of the nerve-bundles of Fig. IX. highly magnified. F. 3.

FIG. XI. — A series of preparations to show the structure of the nerve-fibre, and the
leading types of nerve-cells.

i. A small portion of a nerve-fibre, teased up, and exposed to the action of 1 p.c-
osmic acid for two hours. The segment between the two nodes of Eanvier figured, is seen
to bear one nerve-corpuscle. D. 2.

ii. An isolated fibre from a nerve-trunk, examined immediately after death. The lower
portion of the preparation is drawn after treatment with 1 p.c. osmic acid. F. 4.

iii. A small portion of a dead nerve-fibre similar to the above. F. 4.

iv. A unipolar nerve-cell from the ganglion of a spinal nerve. Teased fresh in eosiu. D. 3.

These cells vary very much in size ; that drawn was a small one.

v. A bipolar nerve-cell from a sympathetic ganglion. Teased fresh in eosin. F. 2.

vi. A multipolar nerve-cell from the anterior cornu of the spinal cord (* of Fig. VIII.).

This preparation shows the continuation of the nerve-cell into an axis-fibre, and was
obtained by teasing up a portion of an anterior nerve-root, isolated together with a small
piece of the grey matter of the cord. Fresh, stained eosin. D. 3.

vii. One of the smaller fusiform nerve-cells from the grey matter of the spinal cord.
Teased fresh. Eosin. D.4.

In Figs. IV. and V. the sheath is indicated by a faint line.

FIG. XII. — Transverse section of the retina. Picric acid. Alcohol. Borax carmine.
F. 3.

The parts shaded darkly are those which stain deepest.

The cells, n.o., usually but two rows deep, may sometimes be three deep as here figured.

FIG. XIII. — Transverse section across the middle of the belly of a small muscle of the
hind limb.

For purposes of comparison with the nerve, the section drawn was of the same absolute
size as that of the nerve-trunk, Fig. IX. Alcohol and borax carmine. A. 3.

The ingrowths of the perimysiuin marked * are very delicate, but they may be readily
traced as they are generally pigment-laden.

FIG. XIV. — One fibre of the above muscle-section, more highly magnified.
Drawn to the same scale as the nerve-fibres in Fig. X.

FIG. XV. — Two preparations of striped muscular fibre.

i. A fresh fibre one portion of which has been ruptured, rendering clear the so-called
sarcolemma. D. 3.

PLATE VI.

•

^,x-^ ^..^

• • • 0 •

I

,0- »

]

VTtrt !<

THE FROG. 23

The muscle-corpuscles are drawn as seen after treatment with 1 p.c. acetic acid and
magenta ; they can, however, be readily observed in the fresh fibre.

ii. A small portion of a similar fibre, examined fresh in normal salt-solution.

The so-called fibrils, fb, were obtained by subsequent teasing-up after death.* F. 4.

FIG. XVI. — Unstriped muscular fibre.

Obtained by teasing up a small piece of intestine, after maceration for some days in
Mailer's fluid. Borax carmine. D. 4.

These cells hang together very tenaciously, and the left-hand portion of the figure
represents a small piece of the entire muscular wall of the above-named viscus, the two
layers of which overlie each other as in life.

Appearances of this kind often constitute serious sources of error.

FIG. XVII. — Transverse section near the middle of the shaft of the femur.
Decalcified with ^ p.c. chromic acid. Alcohol and borax carmine. A. 2.

FIG. XVIII. — A small portion of the above, more highly magnified.
The middle lamella, Im, separates the periosteal bone from that formed by the marrow ;
the direction of growth of these is indicated by arrows. D. 3.

FIG. XIX. — Two adjacent bone-corpuscles, from the thinnest portion of the above
section, drawn under Gundlach's ^th immersion.

FIG. XX. — An entire transverse-section of the ileum ; the muscular and epitheloid layers
are shaded darkly.

FIG. XXI. — A small portion of the same, more highly magnified. Alcohol and borax
carmine. D. 3.

No note is taken of the mucous drops borne by the epitheloid cells (the goblet-cells of
histologists. See Fig. II., i. and ii.)

FIG. XXII. — Section of a small portion of the liver. Alcohol and borax carmine. D. 3.
The bile-capillaries were distended by gently squeezing the biliary fluid back into them
from the gall-bladder, the bile-duct being first ligatured.

The isolated cells, drawn under F. 3, were teased out from the fresh liver in salt

solution.

f The most reliable preparations of striped muscle are to be obtained by the use of the freezing-microtome. The
Golding Bird or Pritchard Machines can be recommended. The most recent reliable accounts of the modern aspects of
the vexed muscle-striation question are those of Ranvier (19), and Rutherford (84). The system of nomenclature here
employed in connection witli nerve, muscle, and bone, is Huxley's.

24

ATLAS OF BIOLOGY.

FIG. XXIII.— Three figures illustrating the structure of the kidney.

i. Portion of a section. Alcohol and borax carmine. D. 4.

The hlood-vessels indicated are generally full of corpuscles — not here drawn.

ii. The ventral surface of a portion of the right kidney after removal of the peritoneum.
Slightly magnified.

The small osculae represent the apertures of communication (nephrostomes) between
the uriniferous tubules and the body-cavity. For details see Spengel (22).

iii. — A glomerulus from a section of the kidney injected from the dorsal aorta. See
Appendix D. Alcohol. D. 3.

FIG. XXIV. — Transverse section of skin. Alcohol and borax carmine. D. 3.
Of the two cutaneous glands figured, the left hand one is represented en face.

FIG. XXV. — Two young ovicells with their investing follicular epithelium. Alcohol
and borax carmine. D. 2.

i. Optical section, ii. Surface view.

The young ovicells such as are here figured, may be easily identified by the absence of
that pigment so characteristic of the ripe ovum (see PI. VI.) They are very small and
quite white, and do not always completely fill the follicle as did the one. drawn in section
above.

For figure of a section of the Frog's ovary see Marshall (16).

Fig. XXVI. — Spermatozoa, obtained by teasing up a small portion of the testis.

The head is often carried as at *, thus giving rise to very deceptive appearances. Of
the spermatozoan aggregates figured, that of the left side had attached to it a cell of the
germinal epithelium. See Bloomfield (1).

a. Artery.

ax. Axis fibre.

b.m. Muscle bundle (fasciculus).

b.n. Nerve bundle.

b.v. Blood vessels.

c. Cones.

e.a. Anterior cornu.

c.b. Bile capillaries.

c.B. Bowman's capsule.

c.c. Canalis centralis.

c.ep. Ciliated epithelium of the same.

cl Cilia.

cp. White corpuscles.

c//. Bed corpuscles.

c.p. Posterior cornu.

cp.b. Bone corpuscle.

cp.c. Cartilage corpuscle.

cp.m. Muscle corpuscle.

cp.ti. Nerve corpuscle.

cp.t. Connective-tissue corpuscle.

c.v. Blood capillaries.

d. Derma.

d.m. Muscular layer of derma.

d.p. Phragmodisc (septal zone).

(/.«. Sarcodisc (interseptal zone).

ed. Superficial horny layer of epiderma

fd'. Middle layer of epiderma.

ci/". Columnar (Malpighian) layer of

THE FROG.

25

eji. Epithelium.

/. Flagellum.

fb. So-called fibrils.

f.d. Fat drops.

/.</. Fat globule.

ft. Follicular epithelium.

/.n. Medullated nerve fibre.

J.n', So-called non-medullated nerve fibre.

f.w. White connective-tissue fibres.

/.y. Yellow connective-tissue fibres.

<j. Layer of ganglion cells.

(j.c. Cutaneous glands.

y.i. Inner granular layer.

yl. Glomerulus.

g.o. Outer granular layer.

#.s. Germinal spots.

g.v. Germinal vesicle.

Im. Middle lamella.

m. Matrix.

ma. Marrow cells.

m.c. Circular muscular layer.

m.l. Longitudinal muscular layer.

nun. Muscular layer of uucous membrane.

MU. Mucin drop.

n. Nucleus.

nd'. Ranvier's node.

tuF. Schmidt's node.

/(.(. Inner nuclear layer.

n.l. Layer of optic-nerve fibres.

n.o. Outer nuclear layer.

«.»•. Nucleus of spermatozoiil.

p. Pia mater.

p.e. Pigmented epithelium.

p.g. Pigment cells.

ph. Sarcophragm (suptal lino).

y/. Plasma.

p.m. Periraysiutn.

p.n. Perineurium.

po. Periosteum.

p.o'. Osteogenic layer of the same.

ps. Pseudopodium.

r. Rods.

r.e. Efferent renal vessels.

sc. Sarcolemma.

se. Serous (peritoneal) layer.

sh. Primitive sheath.

sh'. Medullary sheath.

»/*. Processus spiralis.

tli. Uriniferous tubule.

tb'. Ciliated segment of the above.

ur. Ureter.

v. Vein.

v.c. Vascular connective tissue.

c

PLATE VII.

. .

• .Hi,

n A Co

THE FROG. 27

PLATE VII.

THE FROG. — EMBRYOLOGY AND LARVAL METAMORPHOSES.

FIG. I. — The segmenting ovum, on the appearance of the first cleavage furrow.
FIG. I*.* — Section of the same, at right angles to the furrow.

FIG. II. — The same, on the appearance of the second furrow, viewed slightly from
above.

FIG. IIa. — The ahove, seen from beneath.

FIG. III. — The same, on the appearance of the third — first horizontal — furrow.

FIG. III*. — The same, seen from above.

FIG. IIP*. — Longitudinal section of the same.

FIGS. IVB. and IV. — Two phases in the segmentation of the ovum, on the appearance
of the fourth and fifth furrows.

FIG. V,* — Longitudinal vertical section, at a slightly later stage than the above.

FIG. VI. — A later stage. The upper pigmented pole is seen to be dividing more
rapidly than the lower.

FIG. VII. — A still later phase in the same.

FIG. VIP. — Longitudinal vertical section of Fig. Vlf.

FIG. VIII. — The segmenting ovum, at the blastopore stage.

FIG. VHP. — Longitudinal vertical section of the same.

(Figs. VIP. and VHP. x 10. All the others x 5.)

Rauber (20) has recently made an elaborate study of the details of the early segmenta-
tion of the Frog's ovum.

FIG. IX. — Surface view at a stage somewhat later than Pig. VIII.
The medullary folds are seen to be approximating at one point ; they finally meet
there and contimie to close in opposite directions, as indicated by the arrows, x 10.

FIG. X. — The young tadpole, at the first appearance of visceral arches. Dorsal view.

* The nnelei of those figures are diagrammatic ; they are only occasionally visible in cells BO large.

2S ATLAS OF BIOLOGY.

FIG. X".— The same, from the left side.
FIG. X". — The anterior end of the above, ventral view.

FIG. XI. The tadpole, at the first appearance of external gills, body segments and the

organs of the higher senses.

The animal is at this period still enclosed within the egg-membranes, the tail being

curved to one side as indicated.

FIG. XIa. — The head of the same, ventral view.

FIG. XII. — The tadpole, on the assumption of the free swimming stage. The external
gills are at their maximum. Dorsal view.

FIG. XIIa. — The head of the same seen from beneath.
FIG. XII'1. — The root of the tail of the same, ventral view.

FIG. XIII. — The head of a tadpole, on the appearance of the opercular fold, seen from
the left side.

FIG. XIV. — The tadpole's head, during the period at which external and internal gills
coexist. Ventral view.

FIG. XIVft. — The same, the branchial chamber being opened up on the right side.

FIG. XV. — The tadpole, at the period in which the last remnants of suckers and first
traces of hind limbs are visible. Ventral view.

FIG. XVa.— The same.

Both branchial chamber and body-cavity having been opened up, showing that internal
gills and lungs coexist.

FIG. XVI. — A late stage of the frog's tadpole.

Both fore and hind limbs are visible, the former still buried up beneath the larval
integument. Ventral view.

FIG. XVII. — The late larva, on the assumption of a prehensile-mouthed exclusively
air-breathing stage. The tail was partly absorbed. Seen from the left side.

(Figs. X. to XVII. all x 5.)

FIG. XVIII.— Longitudinal vertical section of the embryo, at a stage slightly earlier
than that of Fig. X. x lo.

FIG. XIX. — A similar section of a later tadpole.*
From nature, after Goette (8). x 10.

; The blastopove is stated by Spencer (Zool. Any., February 28rd, 1885) to persist as the anus.

THE FROG.

29

Fig. XX. — Transverse section of Fig. IX., to show the mode of origin of the nervous
axis. D. 2.

FIG. XXI. — Transverse section, taken across the middle of Fig. XI.

Owing to the tendency of the body-wall to shrink under the reaction of reagents, the
body-cavity, b.c., rarely appears as spacious as it is here figured.

On the left side a slightly earlier stage in the development of the prorenal duct, re, is
represented, than would be seen at this period. See Fiirbringer (7), and Sedgwick (21).
D. 2.

FIG. XXII. — The anterior portion of a section, through the plane i. — ii. of Fig. XI.,
showing the origin of the visceral clefts and arches, and of the external gills.

The right half of the figure indicates, in outline, the same parts at a later stage ; those
clefts which open up are thus represented, and the opercular fold and a third external gill
which had by this period come into existence, are both indicated by dotted lines. D. 2.

The surfaces marked thus * are those which eventually bear the internal gills.

FIG. XXIII. — A section across the plane iii. — iv. of Fig. XI., to show the mode of origin
of the essential parts of the eye, taken as a type of the higher sense organs.

The right half of the figure illustrates the same at a later stage, after the lens has lost
all connection with the epiderma. D. 2.

Note. — Only the initial stages in the segmentation of the ovum are here figured, and the
central row of drawings, connected together by a longitudinal line, represents sections
through the same plane of a progressive series.

Except in Fig. IX., the arrows follow the direction of growth of the cells at the point
indicated.

at. Arclienteron (midgut).

at'. Postanal gut.

no. Aorta.

ao'. Aortic arches.

<tii. Auditory involution.

b.c. Body cavity.

i>i. Blastopore.

l>r. Branchial arches.

br.a. Branchial aperture.

l»:c. Branchial chamber.

tn-.e. External gills.

br.f. Branchial fold (operculiim).

br.i. Internal gills.

e.c. Cleavage cavity.

'••/. Caudal appendage (tail).

r/i. Notochord.

<•/)'. Subnotochordal rod.

c.v. Cerebral vesicle (brain).

f/>. Epiblast.

/./. Fore limb.

fr. Fronto-uasnl process.

A. Heart.

hj. Horny jaw.

/(./ Hind limb.

hp. Hepatic diverticulum.

hy. Hyoid arch.

f. Coiled intestine.

/. Crystalline lens.

so

ATLAS OF BIOLOGY.

/./. Yolk-hearing lower-layer cells.

mil. Mandibnlar arch.

m.f. Medullary fold.

m.ij. Medullary groove.

»•.//. Muscle plate.

ms. Undifferentiated mesoblast.

na. Nasal involution (anterior nostril).

n.n. Neural (cerebro-spinal) axis.

nc. Nucleus.

n.f. Neural caiml.

n.e. Neurenteric canal.

a. (EsophagUH.

op. Optic cup (retina).

op'. Optic stalk (optic nerve).

]>d. Proctodoeum.

jul'. Aperture of involution of the same (cloacal

aperture).

)il. Pulmonary sac (lung).

jiji. Oral papillae.

re. Prorenal (segmental) duct.

s. Head suckers.

sil. Stomodfeum.

W. Aperture of involution of the same (oral

aperture).

XHI. Somatic mesoblast.

xj>. Splanchnic mesoblast.

ty. Tympano — Eustachian cleft.

t;/'. Membrana tympani.

r.f. Posterior cardinal vein.

THE CRAYFISH

PLATES VIII. to X.

TTTE CRAYFISH.

PLATES VIII. TO X.

THE CEAYFISH.

a. Anus.

«.' Anal valve.

a.a. Antounary artery.

<ib. Abductor muscle.

nl'. 1-6. Abdominal appendages, If'..

a.li. Arthrobranchia, external set.

a.b'. Arthrobranchia, internal set.

nfiil. Abdomen.

a.c. Alary muscles.

ad. Adductor muscle.

(/././/(. Adductor muscle of mandible.

a.y. Anterior gastric muscle.

a.h. Auditory hair.

c/. Archeuteron.

a.m. Articular membrane.

amli. Ambulatory legs.

an. Antennary muscles.

an'. Antennule.

an". Antenna,

a. /i. Abdominal papilla.

ur. Articular facet.

an. Auditory sac.

an'. External aperture of the same.

IK: Brauchiostegite.

l>.c. Branchio-cardiac trunks.

li.i-h. Branchial chamber.

I'.il. " BUe-duct."

hi. Blastoporo.

In: Gill.

br.a. Afferent branchial vessel.

lir.c. Branchio-cardiac groove.

lir.e. Efferent branchial vessel.

la. Basipodite.

c. Carapace.

e.a. Anterior transverse nerve-commissure.

c.an. Annulate corpuscle.

«/. Cardiac chamber.

cd'. Dorsal cardiac ossicle.

cJ". Median cardiac ossicle.

cd.l. Lateral cardiac ossicle.

c.i/. Constrictor muscles of stomach.

c/i. Chela,

v.l.

c.m.

on.

ea.

c.ov.

cp.

c.p.

«./>'.

c.r.

ct'.

ct".

cv.y.

cj;.

CJ'.S.

ilc.

ec.u.
en.
en.o.
e.o.

<-!>•
,'.1.1.

i' /'in.

e.x.

e.»t.

f.V.

f.r.a.

f.t.

.'/•

y.a.

i/.ab.

<in 1-20.

Longitudinal nerve-cnmmissnre.

Muscles of chela (basal joint of).

Cornea.

Ctt-cuui.

Ovoid corpuscle.

Carpopodite.

Cardio-pyloric muscle.

Posterior transverse nerve-commissure.

Crystalline rods.

Cuticular lining of fore gut.

Cuticular lining of hind gut.

Cervical groove.

Coxopodite.

Coxopoditic .»•;.(.

Dactylopodite.

Depressor muscles of stomach.

Dilator muscles of stomach.

Epistoma.

Epiblast.

Ectostracum.

Endopodite.

Endoistracum.

Epiostrocuui.

Epipodite.

Endopleurite.

Epimeron.

Eyestalk.

Endosteruite.

Exopodite.

Extensor abdominis muscle.

Follicular epithelium of ovisao.

Fore gut.

Flexor abdominis muscle.

Fatty connective tissue.

Gastrolith.

Genital aperture.

Abdominal ganglia.

Cerebral ganglion.

Green gland, aperture of.

Siibffisophageal ganglion.

Ganglia 1-20.

Optic ganglion,

ATLAS OF BIOLOGY.

</.«. Germinal spots.

//.r. Germinal vesicle.

li. Heart.

/i.rf. Hypodermis.

/».</. Hind gut.

liji. Hepatic artery.

li.pc. Digestive gland (so-called liver).

hi/. Hypoblast.

?'. Intestine.

i.a. Inferior abdominal artery.

is. Ischiopodite.

i.s. Intersternal membrane.

i.t. Intertergal membrane.

lli. Labrutn.

l.b. Lenticular bodies.

I.e. Liver cells.

l.g. Levator muscles of stomach.

I.t'. Lateral tooth.

I.t." Accessory lateral tooth.

/.c. Levator abdominis muscle.

m. Mouth.

mh. Mesoblast cells.

mil. Mandible.

me. Meropodite.

m.g. Midgut.

m.m. Mandibular muscles.

in. op. Muscles of eye-stalk.

m.p. Mandibular palp.

m.pp. Membrana propria.

nit. Metastoma.

m.t. Median tooth.

ni.f 1-2. Maxilla; 1 and 2.

mxp 1-8 Maxillipedes 1 to 8.

i>.au. Auditory nerve.

lie. Nucleus.

11. {I. Ganglionic nerves. ,

11. iy. Interganglionic nerves.

ii. op. Optic nerve.

n.v'. Anterior visceral nerve.

11. r". Posterior visceral nerve.

n. r. Ovicell.

«.(/. Ovary duct.

n.il'. Cut edge of the same.

ie. (Esophagus.

nl. " Olfactory " setffi.

u/i. Ophthalmic artery.

o.n'. Ovisac, ripe.

u.n". Ovisac, young.

at. Otoliths.

or'. Ovary, anterior lobe.

OK". Ovary, posterior lobe.

p. Pericardia! sinus.

p.li. Pleurobranchia.

p.b'. Rudimentary pleurobranchia.

pc. Ferment cells.

pc'. Secretionary product of the same.

p.c. Procephalic process.

p.ea. Pore canals.

p.g. Posterior gastric muscles.

pi. Pleuron.

pr. Propodite.

pt. Protopodite.

py. Pyloric chamber.

py'. Dorsal pyloric ossicle.

py". Median pyloric ossicle.

pi/.l. Lateral pyloric ossicle.

r. Rectum.

re. Green gland.

vr! . Vestibule of the same.

x. Stomach.

s.a. Superior abdominal artery.

nc. Setae.

ni/. Scaphognathite.

n.x. Sternal sinus.

s.sj>. Striated spindle.

st. Sternal artery.

xt 1-20. Sterna 1 to 20.

sir. Swimmerets.

t. Telson.

//. Tail fin.

/// 1-20. Terga 1 to 20.

th.ii. Thoraeo-abdominal liukvvork.

la'. Testis, anterior lobe.

tx", Testis, posterior lobe.

v'. Dorsal valves of heart.

r". Ventral valves of heart.

»'". Lateral valves of heart.

v.cp'. Lateral cardio-pyloric valve.

v.ep". Median cardio-pyloric valve.

v.d. Vas deferens.

v.p. Valvular termination of lining of fore-gut.

y. Food yolk.

i. to xx. Appendages i. to xx.

i'.toxx'. Articulations for the same.

1. to 20. Segments 1 to 20.

VIII .

A-c f

THE CRAYFISH.

PLATE VIII.

THE CRAYFISH. f — THE EXOSKELETON AND APPENDAGES. THE MUSCULAR SYSTEM.
FIG. I. — The entire animal, from the left side, in the resting attitude ?. Nat. size.

FIG. II. — The same from beneath, all the appendages of the left side and a portion of
the branchiostegite having been removed, in order to display the whole sternal surface.

The last ambulatory leg is drawn in its functional position, as the chief lover in forward
progression. The feeler of the antenna is indicated as underlying the chela, in error. Nat.
size.

FIG. III. — Median vertical-longitudinal section of the same, the soft parts having been
removed, after boiling in 10 p.c. potash solution. Nat. size.

FIG. IV. — Transverse section of the thorax, taken immediately behind the bases of the
great chelae, treated as in Fig. III.

The small ingrowths marked thus * give part attachment to the levator muscles of the
fore-gut, and may be appropriately termed endotergites. x 2.

FIG. V. — The third abdominal segment of the ? , seen from behind.
On the left side the parts are represented in section, for purposes of comparison with
Fig. IV. x 2.

FIGS. VI. to XXII.— The appendages. All x 3.

Only the typical ones are drawn. Taking the second maxillipede (Fig. VI.) as a
central type, the others arc represented in series, the divergent lines of which are indicated
by arrows.

All are drawn in the relatively natural position, their posterior surfaces being alone
represented.

VII. — A portion of the third maxillipede, to show the fusion of the ischiopoditc and
basipodite, characteristic of it and the great chela.

VIII. — The pemiltimate ambulatory appendage.

IX. — The two terminal joints of the first ambulatory leg.

X. — The gill-bearing portion of the Lobster's third ambulatory appendage.

XI. — The first maxillipede of the Crayfish.

* All the figures of Plates VIII. to X., uuless otherwise stated, refer to the Red-footed French Crayfish (.I* oeiw
tlnciatili», var. nobilii), specimens of which can often be obtained in our English markets 5 to 6 inches in length.

36 ATLAS OF BIOLOGY.

XII. — The second maxilla.

XTIL— The first maxilla.

The coxopodite of this appendage is carried, during life, inserted into the mouth.

(Compare Plate IX., Fig. V.)

XIV.— The mandible.

The endopodite of- the second maxilla, Fig. XII., en, is carried, during life, hooked
over the recess marked*.

XV. — The antenna.

XVI.— The antennule.

XVII.— The eye-stalk.

XVIII. — The third abdominal appendage of the ? , taken as a type of that series.

XIX. — The second abdominal appendage of the <?.

XX. — The first abdominal appendage of the 3 .

XXI. — The same of the ? .

This limb varies very much in size in different individuals ; the extremes observed are
indicated by the two lines drawn to the left.

XXII. — The last abdominal appendage.

FIG. XXIII. — The three terminal joints of the right chela, laid open, to display their
muscles.

The dotted lines indicate the positions of the underlying tendons. Nat. size.

FIG. XXIV. — Longitudinal section of the whole animal, all the soft parts having been
removed, with the exception of the muscles.

Portions of the great gastric muscles (compare Fig. VII., Plate IX.) and of those
connected with the basal joints of the chela, antenna, and mandible, have been left. Nat.
size.

This dissection is best performed upon an animal previously hardened in alcohol.

PLATE IX

THE CRAYFISH. :»7

PLATE IX.

THE CKAYF1SH. — THE GENERAL DISPOSITION OF THE VISCERA. THE ORGANS OF
ALIMENTATION, CIRCULATION, AND RESPIRATION.

FIG. I. — A general dissection from the dorsal aspect.

The whole tergal skeleton has been removed. The extensor-abdominis muscle, the
greater part of the generative apparatus, and part of the anterior gastric muscle together
with the procephalic process, have been removed on the left side ; the adductor muscle
of the mandible has been cut short, and the digestive gland (so-called liver) dissected away
to the level of its central duct.

On the right side the gills were removed, to show the extent of the branchial
chamber. <?. x 1£.

FIG. II. — The stomach and anterior portion of the intestine, after removal from the
body, seen from above.

The attachments of the gastric muscles (approximators of the gastric teeth) are shown
on the left side.

The whole fore-gut was divested of its outer cellular coat.

FIG. HI. — The same, in median longitudinal section, the wall of the fore-gut being left
entire.

FIG. IV. — The terminal portions of the hind-gut and abdomen, in longitudinal
section.

FIG. V. — Transverse section of the fore-gut, passing through the oesophagus imme-
diately behind the anterior gastric muscle ; a young gastrolith, y., was present.

The metastoma and basal joint of the first maxilla are drawn in natural position.

C.T.V. should read bs.v. in this figure.

In Figs. III. to V. the cut edges of the cuticular lining and its related structures are
drawn in black.

FIG. VI. — Outer view of the gastrolith.

(Figs. II. to VI., all x 2.)

FIG. VII. — Dissection from the left side, to show the leading muscles of the fore-gut,
and — incidentally in section — the labrurn, a portion of the metastoma and the procephalic
process.

The specimen was previously hardened in alcohol. x 1£.

In dissecting the above, the opportunity should not be lost of noting the extent to
which the calcifications of the chitinous wall of the stomach are determined by muscular
attachment.

38 ATLAS OF BIOLOGY.

FIG. VIII. — Transverse section of one of the digestive co3ca.

The preparation drawn was frozen in gum, by means of the " Golding Bird" ether
microtome; the sections were transferred as ciit to 1 p.c. osmic acid solution, the fatty
globules of the liver-cells (I.e.) being thus stained black, as drawn. D. 3.

Weber (37), who first fully elucidated the real nature of this so-called liver, significantly
termed it the " hepato-pancreas."

FIG. IX. — Dissection from the left side, to show the relations of the gills.

The branchiostegite was removed, the larger appendages were cut short, and only
sufficient of the bases of the branchiae borne by them were left to indicate their positions.
(Typical podobranchiae are figured, in detail, on Plate VIII.)

The shaded areas represent the interarticular membranes, a.m. x 11.

FIG. X. — The same, after injection of the branchio-cardiac trunks, and their factors —
the efferent branchial vessels.

All the branchiae were removed, excepting the solitary functional and the three vistigial
pleurobranchiee, _p.Z>. These were, in this specimen, at their maximum of development, x li.

In injecting, the branchiostegite was first dissected off, and a small hole drilled in the
carapace from above ; through this the syringe was inserted into the pericardial sinus,
injection being completed before the removal of any of the gills.

FIG. XI. — The pericardial sinus, the heart and related structures, as seen from above.

The pericardium was opened up, after 24 hours in alcohol ; the left side of the heart
was removed to the level of its lateral valve, and sufficient of the extensor abdominis muscle
dissected out to render clear the osculae of the branchio-cardiac trunks.

FIG. XII. — The heart, after removal from the pericardium, seen from the ventral aspect.
The hepatic artery of the left side was torn away at its base ; only its aperture therefore
is indicated.

(Figs. XI. and XII. x i|.)

FIG. XIII. — The arterial system and pericardial sinus, seen from the left side.

The specimen was pinned down in the position drawn, sufficient of the carapace being
removed to expose the lateral cardio-pericardiac valve ; from the aperture bounded by this
injection was performed.

With the exception of the last ambulatory limb, the genital duct related thereto and
the posterior gastric muscle, the entire postoral portion of the body was, on the left side,
removed to the level of the middle line and with it the digestive gland. All the organs in
front of and including the inaudible, were left untouched.

The pericardial sinus — the limits of which are indicated in deep black — was carefully
dissected after two days' immersion in alcohol, s . x 1|.

All the arteries give off— in addition to those branches here figured — small ones to
immediately adjacent parts.

THE CRAYFISH. 39

Fio. XIV. — Transverse section across the thorax, between the twelfth and thirteenth
appendages, after injection as described for Fig. XIII.

Specially designed to show the great blood passages in relation to the gills.

On the left side all the parts are drawn in situ, the muscles and gills included.

On the right the muscles connected with the basal joint of the second ambulatory leg
were removed, to fully expose the sternal sinus.

The gills of the right side are diagrammatic, and no note has been taken of the blood-
spaces surrounding the extensor and levator-abdominis muscles.

The arrows indicate the course taken by the blood in life.

The central duct of the digestive gland is best seen after preservation in alcohol. <J . x 3.

The sternal artery is represented in Figs. XIII. and XIV. as passing to opposite sides
of the intestine. There is no rule in this matter.

To complete the study of the blood- vascular system, the circulation should be witnessed
under the microscope in some small transparent form. Asellus answers admirably.

PLATE X.

THE CRAYFISH. 41

PLATE X.

THE CKAYFISH. — NERVOUS SYSTEM AND SENSE ORGANS. THE HISTOLOGY OF THE
EXOSKELETON. THE RENAL AND REPRODUCTIVE ORGANS, AND DEVELOPMENT.

FIG. I. — The nervous system, dissected from above.

The dorso-lateral skeleton, together with the large muscles and the viscera — exclusive of
the alimentary canal — were removed ; the intestine was severed in order that the visceral
nerves might be seen.

On the right side the endophragmal system was left untouched, while on the left it and
all else were removed, to the level of the articulations of the appendages ; these are indicated
by a shade. The left half of the rostrum was dissected away, and the eye-stalk opened
up. 3. • x 2.

This figure illustrates the relations borne by the nervous system to the body segments ;
having made that out, the student is recommended to remove the whole nerve-chain and
examine it under water on a black surface.

FIG. II. — Median longitudinal section, through the eye stalk. Chromic acid pre-
paration. A. 2.

The zones of the rod and spindle layer shaded over, are those at which pigment is most
fully developed.

FIG. III. — A portion of the cornea, stripped off and examined under water. D. 3.
This figure is an accurate drawing of a portion in which the ordinary typical square
facets graduate into hexagonal ones, both types beiug present in Astacus.

FIG. IV. — Three of the crystalline bodies from a fresh eye, teased up iu water.
The middle one is drawn en face, the right hand one from the side ; the pigment it>
indicated in connection with the left hand one alone. D. 3.

- FIG. V:— The left antennule, dissected in situ from within.

The inner wall was removed to the level of the auditory sac, which was in part opened
up. x 6.

FIG. VI. — Two of the exopoditic sensoiy hairs of the above, drawn in the natural
position, the exopodite being in life directed upwards as in Fig. V. (Compare Fig. I.,
Plate VIII.) D. 3.

FIG. VII. — A small portion of the auditory sac, viewed from within, after removal from
the body.

The sandy particles functional as otoliths, are indicated in the upper portion of the
figure alone. The line of attachment of the auditory hairs coincides with that described by
the nerve, n.au., of Fig. V. D. 3.

42 ATLAS OF BIOLOGY.

FIG. VIII. A small portion of a thin transverse section across the ischiopodite of the

third maxillipede.

The pore-canals are drawn in the upper half of the figure alone ; they are closer together
than here represented. D. 3.

FIG. IX. — Portion of a tangential section of the same.
These sections were ground down on a rough surface. See Appendix H.
The appendage chosen for the above is an instructive one, as all gradations of the
exoskeleton, from the seta to the cutting tooth, can readily be obtained in the same slice.

FIG. X. — The excretory organ of the left side, dissected from without, a portion of its
duct of communication with the exterior having been opened up. x 2.

Wassiliew (36) states that the green gland consists of an unbroken tube of three
segments.

FIG. XI. — The male reproductive organs, drawn from above.

The right limb was straightened out to show the whole course of the vas deferens, a
portion of which was opened up. x 3.

FIG. XII. — A ripe spermatozoau. D. 3. Fresh.

FIG. XIII. — The female reproductive organs, dissected as for Fig. XI.
The central cavity of the ovary has been laid bare on the left side. x 2.
Figs. XI. and XIII. were drawn from sexually mature specimens, and therefore represent
the organs as they appear during the breeding season.

FIG. XIV. — Two stages in the development of the ovisac. D. 3.

A small portion of the germinal epithelium was selected, as described for that of the
Frog (Plate VI., Fig. XXV.), and placed on a slide in magenta solution. To avoid undue
pressure, a cover-slip was placed on either side of the preparation, upon which to support
that covering the object. Modified from Huxley (29).

FIG. XV. — Surface view of the Crayfish ovum at the close of segmentation (a stage
equal to that of the Frog, Fig. VIII., Plate VII.) 2 inch objective.

FIG. XVI. — Longitudinal section of a portion of the same, through a plane corre-
sponding with that of the reference line, bl, of Fig. XV. D. 2.
For further details see Eeichenbach (33).

FIG. XVII. — A surface view of the embryo at an early stage (the equivalent of the free-
swimming " Nauplius " stage of the typical Crustacean development).

FIG. XVIII. — Side view of an older embryo. After Kathke (32).

THE CRAYFISH. 43

FIG. XIX. — The advanced Crayfish emhryo, just prior to the first moult ; drawn after
removal from the swimmerets of its mother.

The successive stages of the Crayfish development are figured and fully described in
Kathke (32) and Huxley (29).

FIG. XX. — An embryo Lobster, shortly after the appearance of its swimmerets.
Sars (35) has published excellent drawings of all the larval metamorphoses of this
animal.

(Figs. XVII. to XX. were drawn under a two-inch objective.)

FIG. XXI. — The third abdominal and sixth thoracic appendages Cthe latter lettered ii.)
of the above, drawn to the same scale. A. 2.

/

THE EARTHWORM

PLATES XI., XII.

J

THE EARTHWORM.

47

PLATES XI., XII.

THE EARTHWORM.

a. Anas.

lie. Unreal sac.

be'. Muscles of the same.

lit. Passive portion of spermatozoid forming

body.

e. Cuticle.

cy. Clitellum.

c.l. Longitudinal nerve-commissure.

em. Circular blood vascular commissure.

cm'. Interneural blood vascular commissure.

CM. Circumcesophageal nerve-commissure.

CM. Epitheloid lining of alimentary canal.

c.«'. Subepitheloid vascular layer of the same.

e.e. Ciliated epithelium.

e. in. Mesentery of excretory organ.

e/i. " Hypodermis."

ep'. Cells of the same.

ex. Epithelium of excretory (segtnental) organ.

t.i1. Blood-vessels of excretory organ.

<•.(/. Excretory plexus.

Jl. Flagellum.

ij.e. Supraoesophageal ganglion.

<j.i. First ventral ganglion.

ijl. Cutaneous glands.

yi. So-culled capsulogeneous glands.

i/l". Gland at base of vas deferens.

IJ.H. Gauglionic swellings.

ij.t. Germinal vesicle.

ijz. Gizzard,

/i. So-called " hearts."

lip. So-called " liver."

i. Intestine.

i'. Intestinal sacculiu.

/./. Lateral intestinal blood-vessel.

('./'. Loop of hepatic tissue surrounding the

same.

/.*. Supra intestinal vessel.

t..s'. Subintestinal vessel.

HI. Mouth.

in.<: Circular muscles of body wall.

tn.c.' Circular muscles of alimentary canal.

m.c'. Circular fibres of mesentery.

m.l. Longitudinal muscles of body-wall.

in. I'. Longitudinal muscles of alimentary canal.

m.r. Radiating fibres of mesentery.

HI.*. Mesenteria septum.

n.a. Circumneural arcade.

iic. Nucleus.

«c'. Corpuscles of red blood.

tic1. Heads (nuclei) of developing spermatozoa.

n.c. Nerve-cells.

n. ;i. Gaugliouic nerves.

ii.iij. Interganglionic nerves.

/i./. Lateral neural vessel.

H.S. Supraneural vessel.

«.*'. Subueural vessel.

od. Oviduct.

• »/'. Internal aperture of the same.

ml". External aperture of the same.

<e. (Esophagus.

<«'. Crop.

".//. (Esophagoal (calciferous) glands.

ix.ij'. Apertures of the same.

<«./. Lateral ojsophagoal blood-vessel.

ue. Ovary.

ov'. Young ova.

or/'. liipe ovum.

ji. Peritoneal membrauc.

fi.d. Dorsal porr.

j>y. Pigment.

ph. Pharynx.

)</('. Muscles of the same.

ph.". Sucker-like fold of pharynx.

p.m. Protractor muscles of seta,'.

p.g. Prostomium.

/>r.*. Peristomium.

;•.///. lietractor muscles of seta,'.

*.' Functional seta.

»*. Follicle, bearing young seta;.

sy. Segmental organ.

ty'. Its thin-walled segment.

*y". Its thick-walled segment.

«</'". Its muscular segment

ttj.e. External aperture of segmental organ.

48

ATLAS OF BIOLOGY.

xi/.i. Internal aperture of segmental organ.

sh. Integumentary sheath of seta.

*/('. Cuticular sheath of seta.

*./. Lateral seta?.

*»». Semitic constriction.

s.n. Muscular sheath of nervous system.

s.n'. Tubular fibres of the same.

471. Spermathecas.

«/>'. Apertures of the same.

s.s. Sac of sete.

s.v. Ventral setas.

l]>. Typhlosole.

ta. Testis.

v.d. Vas deferens.

v.d'. Internal aperture (mouth or ciliated rosette)

of the same.

v.d". External aperture of the same.

v.d'". Coiled loop of the same.

v.s. Vesiculas seminales.

zn. Zonitic constrictions.

1. to 86. Body segments 1 to 86.

PLATE XI

' -."•:•'• '/#£ "-••'

THE EARTHWORM. 4!»

PLATE XI.

THE EARTHWORM. — THE EXTERNAL CHARACTERS. THE ALIMENTARY CANAL AND ITS

APPENDAGES. THE EXCRETORY ORGAN, ETC.

FIG. I. — Dorsal view of the anterior end of the body of a sexually mature worm.
The zonitic markings, zn., may often be more than one in number for each segment,
especially in the generative region.*

FIG. II. — Ventral view of a portion of the same.

FIG. III. — Ventral view of the terminal segments of the same, the anus slightly
upturned.

Figs. I. to III., all x 2.

FIG. IV. — Ventral view of the first seventeen segments, after removal of the cuticle ;
a portion of the integument of the left side has been pinned out, to show the openings of the
spermathecse.

The apertures of the segmeutal organs are not indicated. (Compare Fig. V.,
Plate XII.) x 3.

FIG. V. — The same, seen from the left side.

Either spermatheca may open by two apertures, as did the hinder one in the specimen
figured, x 2.

FIG. VI. — Two setae, drawn to the same scale.

The right hand one is from the genital region, and the left from a postgenital segment.

* Indicates an axial differentiation. A. 3.

FIG. VII. — A small portion of the cuticle, with the cuticular sheath of a seta.

* These refractive dots appear to be due to the presence of enclosures. D. 3.

FIG. VIII. — The alimentary caual exposed from the dorsal aspect, its roof having been
subsequently removed on the right side. x 2|.

The two hinder pairs of calciferous glands may often be absent, and the mesenteric septa
in the crop-gizzard region are subject to variation. t

* In this and the following plate, the numbers of important segments are indicated wherever desirable in small
Arabic numerals.

f The brownish-yellow tissue, usually termed liver, hns no direct connection with the lumen of the alimentary cannl.
It is always associated very largely with the blood-vessels, and is in all probability a direct derivative of their walls.
It appears to be active in the production of some constituent of the blood, similarly to that tissue described by
Lankester in the Leeches as vaxifuctiri'. See Lankester " On the Vasifactive and Connective Tissues of the Medicinal
Leech," Q. J. M. .S'., vol. xx., 1880. Also papers by Weldon on the Vertebrate Kidney and Supra-renal bodies,
the same journal, vols. xxiv. and xxv. I have observed, in cells of the alimentary epithelium teased up shortly after
death, the presence of imjested particles of decomposing vegetable matter. In the absence of true digestive glands, and
of any knowledge of the physiology of alimentation in this animal, the probability of an intracellular digestion of this
solidly ingested food material must not be overlooked. (Compare Hydra, PI. xvii., fig. v., el *f<j.)

1

50 ATLAS OF BIOLOGY.

FIG. IX. — Enlarged drawing of the left half of somite XV., after removal of the crop
specially to show the position and segments of the excretory organ. The loop marked *
is ciliated, x 25.

lu order to make out the natural relations of the excretory organ, it is advisable to
preserve the animal in alcohol for a day or two, prior to dissecting.

FIG. X. — Terminal left-hand portion of Fig. IX. magnified, the looped blood-vessels of
one side being indicated. D. 3.

These vessels usually bear numerous knotted appendages [see Lankester (48) and
Claparede (42)]. They are often, as in the specimen here figured, wholly absent. D. 3.

FIG. XI. — A portion of the same, viewed in optical section. D. 3.

FIG. XII. — The mouth of the excretory organ. D. 3.

This can only be removed from the 'body, together with a portion of the mesentery
which it perforates.

The whole structure of the Earthworm's excretory organ has been most successfully
worked out by Gegenbaur (44), and Claparede (42).

f

FIG. XIII.- — Dissection from the left side, showing especially the alimentary canal in
section, and incidentally, the nervous system and genital organs, x 2^.

Eighteen hours' previous immersion in alcohol is here necessary, in order that the parts
may be well set in their natural positions.

Of the cesophageal glands the two hinder pairs are always smaller than the one in front,
and their apertures are sometimes obliterated (see Fig. VIII.)

PLATE XJI.

•m.l.

... <!.] a A n»l

THE EARTHWORM. 51

PLATE XII.

THE EARTHWORM. — THE OBGANS OP CIBCULATION, REPRODUCTION AND LOCOMOTION.
THE NERVOUS SYSTEM. THE LAYEKS OF THE BODY-WALL, ETC.

FIG. I. — The so-called hearts, and the great blood-vessels of the anterior twelve
segments, seen from the left side. x 2^.

Dissections of the blood system of this animal are best performed on specimens some
six to eight hours dead.

FIG. II. — The vessels of three postgenital segments, seen from the left side.

The excretory vessels are shown in the posterior one, all except the excretory vessels
in the middle one, and the circular commissural vessel in the anterior one.

In order to see the lateral-intestinal trunks, i.L, the so-called hepatic tissue must be
carefully scraped away.

The subintestinal vessel, -i.s'., Figs. II. and V., is very obvious on the under surface of
the gizzard, the walls of which are white. x 6.

FIG. III. — A drop of the peri visceral lymph fluid, examined fresh.

The nuclei respond most readily to the action of 1 p.c. acetic acid and magenta. D. 3.

FIG. IV. — A drop of the red blood fluid, drawn from one of the so-called hearts with
a pipette. F. 3.

FIG. V. — Entire section across the middle of the body.
Constructed from a number of sections and dissections.
The excretory organs are diagrammatic. x 0.

FIG. VI. — The portion a-b of the same, highly magnified, to show the order of suc-
cession of the layers of the body-wall and of that of the alimentary canal ; also the seta?,
with, their sheaths, muscles, etc. D. 2.

The excretory organ is here disregarded.

Mojsisovics (50) has described and figured an epitheloid blood-plexus for the clitellum.

FIG. VII. — The anterior portion of the nervous system, seen from above.
The pharynx was displaced, and the left circumo3sophageal commissure is supposed to
be seen through it. x 31.

FIG. VIII. — A portion of Fig. VI., being a thin section of the nerve ganglion with
its muscular sheath, etc.

The nerve-cells here figured are diffused along the entire length of the nervous axis.
[Compare Claparede (42), Plate XL VII., Fig. VI.] D. 3.

52 ATLAS OF BIOLOGY.

The sections from which Figs. V., VI., and VIII. were drawn were prepared from an
auirnal preserved in \ p.c. chromic acid (the contents of its alimentary canal having been
first washed out with the same fluid), and afterwards hardened in alcohol.

FIG. IX. — The reproductive organs, displayed from above.

The left half of the figure represents the immature, and the right half the sexually
mature condition, so far as the male organs are concerned. Spirit specimen, x 6.

The spermathecaB generally underlie the mesenteric septa 9-10 and 10-11 ; they may,
however, grow either into the ninth and tenth, or the tenth and eleventh segments.

FIG. X. — The initial stages in the development of the spermatozoa, obtained by
squeezing out a drop of the contents of the seminal vesicle upon a slide. Stained with
magenta. F. 3.

The figures d and / are drawn in optical section, e is seen en face, g represents three
adult spermatozooids.

For further details concerning the male organs se~> Heriug (45) and Bloomfield (41).

FIG. XI.— The ovary.

The ovum, ov.", was ripe and ready for dehiscence. D. 3.

THE SNAIL

PLATES XIII., XIV.

THE SNAIL.

55

PLATES XIII., XIV.

THE SNAIL.

n. Anas.

a.fll. Albumen gland.

•i. !/!'. Duct of the same.

al. Archenteron.

ao. ' Aorta.

mi' . Anterior aortic trunk.

ao''. Posterior aortic trunk.

. an. Auricle.

mi, I. Auditory organ.

and'. Auditory nerve.

l>. Buccal nerve.

//. Buccal ganglion.

h.il'. Right bile-duct.

li.d". Left bile-duct.

W. Blastopore.

b.ni. Buccal mass.

r. Coluruella.

e.r. Cleavage cavity.

e.g. Cerebral ganglion,

c/. Genital vestibule.

c.m. Constrictor muscle.

e.]>. Cerebro-pedal commissure.

c.ps. Cerebro-splanchnic commissure.

cr. Crop.

er1. Its cut edge.

d. Dart sac.

d'. Valves of the same.

(/". Spiculum amoris.

d.m. Depressor muscles.

tp. Epiblast.

/. Foot.

//. Flagellnm.

g.a. Genital aperture.

;/.(/. Genital duct.

<;''. Groove at base of excretory orifice.

</.*. Germinal spot.

//.'. Ganglion of so-called olfactory tentacle.

.'/•''. Ganglion of optic tentacle.

ij.f. Germinal vesicle.

h. Heart.

h.d. Hermaphrodite duct.

h.d'. Aperture of the same.

h.ijl. Ovotestis (hermaphrodite gland).

li.nl'. Depression for the same.

h.j. Horny jaw.

lii/. Hypoblast.

i. Intestine.

i'. Origin of the same.

/.///. Intrinsic muscles.

I'. Circular lip.

I". Lateral lip.

Hi. Labial nerve.

l.m. Leva tor muscle.

l.x. Lateral blood sinus.

l.t. Lateral (rachidian) teeth.

If. So-called liver.

/r'. Liver, right lobe.

/c". Liver, left lobe.

in. Mouth.

m.ijl. Accessory glands.

ins. Mesosoma.

in.t. Median teeth (uncini).

HC. Nucleus.

n.c. Nerve collar.

a. t. Nerve to tentacle.

rt.t'. Nerve to optic tentacle.

o.e. Odontophoral cartilage.

od. Oviduct.

tf. Oesophagus.

op. Visual organ.

op'. Optic nerve.

ot. Otolithic mass.

p. Peritreme.

pc. Pericardium.

pd. Pedal ganglion.

pd'. Pedal nerves.

/i.i/l. Pedal gland.

/'/. Pulmonary sac.

/it . Pulmonary chamber.

pi'. Respiratory aperture.

pl.m. Pallial muscle.

/i. in. Protractor muscle.

/ni. Penis.

/i. n. Pallial nerve.

56

ATLAS OF BIOLOGY.

pr. Prostate.

p.s. So-called Parieto-splanchnic ganglion.

p.v. Afferent pulmonary vessels.

p.v'. Efferent pulmonary vessels.

r. Rectum.

r'. Cut edge of the same.

rd. Radula.

rd'. Sac of the radula.

re. Renal organ.

re1. Renal duct.

re". Renal aperture.

r.m, Columellar (retractor) muscles.

•r.m '. Retractor pedis muscle.

r.m". Retractor muscle of buccal mass.

r.p. Retractor muscle of penis.

r.t. Retractor muscle of tentacle.

r.v. Afferent renal vessels.

r.t)'. Efferent renal vessels.

s. Shell.

«'. Its cut edge.

xd. Stomodfeuin.

*.//. Shell gland.

*/. Salivary gland.

si'. Salivary duct.

si". Aperture of the same.

*.». Nerves to the same.

y/>. Spermatheca.

xt. Stomach.

t. So-called olfactory tentacle.

t'. Optic tentacle.

t.ti. Tentacular artery.

tph. Intestinal valve.

v. Subtentacular lobe (modified remnant of

velum). For Plate XIII., ventricle.

va. Auriculo-ventricular valves.

v.c. Blood sinus of visceral sac.

v.c.p. Circulus venosus pulmonis.

v.d. Vas deferens.

vi/. Vagina.

v.n. Visceral nerve,

r.s. Visceral sac.

».»'. Its cut edge.

.-.Ill

K.gl

THE SNAIL. 57

PLATE XIII.

THE SNAIL (Helix aspersa). — EXTERNAL CHARACTERS. THE SHELL. THE ALIMENTAKY,
CIRCULATORY, KESPIRATORY, AND EXCRETORY ORGANS.

FIG. I. — The living animal, from the right side.
FIG. II. — The same, from the front.

FIG. III. — The shell, in median longitudinal section through the columellar axis. The
attached ends of the great retractor muscles were left.

FIG. IV. — The hybernaculum (hypophragm), after removal from the shell.

(Figs. I. to IV. all nat. size.)

FIG. V.- -The alimentary canal, with its appended glands and associated muscles, from
the right side.

On cutting open the pulmonary chamber, dissecting out the rectum and removing the
generative organs and nervous system, the parts fall naturally into the positions here
figured.

The stomach and portions of the bile-ducts and intestine have been opened up. x 2.

The so-called liver of the gasteropod is stated by Barfurth (56) to perform, among
other functions, those of a hepato-pancreas. (Compare Astacus, Plate IX., Fig. VI.)

FIG. VI. — The horny jaw, viewed from the front in situ, x 3.

FIG. VII. — Median longitudinal section of the buccal mass and pedal gland, from the
right side, x 4.

Sochaczewer (80) claims for the above gland an olfactory function.

FIG. VIII. — Transverse section across the sac of the radula. x 8.

FIG. IX. — A portion of the radula, magnified.
The middle row of teeth has been stippled. A. 2.

FIGS. X. and XI. — The median and first lateral tooth of the right side, in situ.
FIG. XII. — One of the outer lateral teeth of the same side. D. 2.

FIG. XIII. — Dissection to show the heart, pericardium, and the excretory organ.

The pulmonary sac was slit open in a line with the respiratory aperture, and the outer
wall of the excretory organ removed, to show its internal structure. Both the pericardium,
and heart were opened up. x 2£.

8

r,8 ATLAS OF BIOLOGY.

The excretory groove, gr., cut across, lies in life altogether to the left of the respirator

orifice.

The rerjo-pericardial communication is not figured ; it is very small, and differs in no
important respect from that drawn and described by Niisslin (76) for Helix pomatia.

FIG. XIV.— Obliquely transverse section through the whole body and shell, taken just
in front of the columella. Spirit preparation, x 3.

FIG. XV. — Dissection from the right side, after injection from the large pulmonary
vein, p.v.', to show the chief arteries.

The visceral sac and body- wall of the right side were dissected away in toto ; the
retractor muscles, genital ducts, and rectum were all in part removed, as shown by their cut
ends drawn. The rectum was turned back, and the heart and right lobe of the liver a
little displaced. All else is figured in situ. x 2.

The artery running longitudinally along the foot overlies the pedal gland.

FIG. XVI. — Dissection, after injection, to show the leading venous sinuses, together
with the respiratory and renal capillary systems.

The arteries were injected from the pulmonary vein (afferent pulmonary vessel), p.v.', and
the venous lacunae, pulmonary circulus, and afferent pulmonary vessels from the point
marked *.

The pulmonary sac was severed close alongside the rectum, in order to show the whole
respiratory plexus in one view, x 2.

The position of the lateral pedal sinus, l.s., is indicated in life by a light band which
runs along the side of the foot. On withdrawal of the body into the shell this sinus becomes
greatly distended by displacement of the perivisceral fluid, and I know of no more satisfac-
tory means of demonstrating a lacunar blood system, than that afforded by injection from
this receptacle.

XIV

THE SNAIL. 59

PLATE XIV.

THE SNAIL. — THE NERVOUS SYSTEM AND SENSE OIIGANS. THE REPRODUCTIVE ORGANS

AND THE GASTEBOPOD LARVA.

FIG. I. — Dissection to show the leading ganglia and nerves, from the right side.

The lung-sac was opened up, cutting along the edge of the rectum, the rectum itself
being next severed and reflected, as drawn. The hody-wall was then removed on the right
side from the head to the albumen gland, and along with it the tentacles, a good portion
of the foot and the greater part of the genital apparatus, x 2.

PIG. II. — Dissection from above, to show some of the important nerves, and incidentally
the tentacular and other retractor muscles.

The pulmonary sac and body cavity were opened up from above by a clean cut,
passing to the right side of the excretory organ, and the two halves were reflected.

The tentacles of the left side were cut open. The crop, retractor muscle of the buccal
mass, and the genital apparatus, were all for the most part removed, their cut ends being
drawn, x 2.

In both the above figures the whole nervous system is drawn in deep black. The
sheath of the nerve-collar, having been for the most part removed, is not indicated.

FIG. III. — The circumcesophageal nerve-collar, after removal from the body, seen from
behind, x 3.

The dotted lines indicate the limits of its sheath.

The so-called parieto-splanclmic ganglia, ^.,9., represent those known as visceral,
pleural, and abdominal, in allied forms. Spengel (81) has recently instituted an elaborate
inquiry into the whole question of their morphology.

FIG. IV. — An enlarged view of the tentacles of Fig. II., to show their nerves,
ganglia, and the visual organ, in situ.f x 6.

FIG. V. — The otocyst, seen in situ. D. 3.

FIG. VI. — The generative apparatus, after removal from the body.

The vestibule, cl., and adjacent parts have been opened up, at * is exposed the fold
which incompletely subdivides the lower part of the hermaphrodite duct. x 2.

The ovotestis is best got at by removing it together with the right lobe of the liver,
and then dissecting it out carefully. (Compare Figs. V. and XV., Plate XIII.)

t The condition of the nervous structures lodged within the optic tentacle clearly points to the conclusion that it
performs a double function. See W. Flemming, " Untersuchungen uber Sinnerepithelien der Mollusken," Archr. Mk.
Anat., vol. vi., 187''.

60 ATLAS OF BIOLOGY.

FIG. VII. — The dart-sac in transverse section, x 2.

Careful examination shows that the blades of the dart are slightly twisted, so that it
must leave its sac in the fashion of a revolving gun-shot.

FIG. VIII. — The spermatozoa. F. 3.

i. Two isolated spermatozoa.

ii. A spermatozoan aggregate.

iii. A group of immature spermatozooids.

FIG. IX. — Two ova, obtained, as were the above spermatozoa, by teasing up a small
piece of the ovotestis in eosin solution. D. 3.

FIG. X. — The ovum of the Pond snail* (Lymnaus stagnalis) during segmentation, seen
from beneath. D. 2.

FIG. XI. — Side-view of the same.

FIG. XII. — The same, at the gastrula stage, in optical section. D. 2.

FIG. XIII. — The early larva of the same. Surface view from the side. D. 2.

FIG. XIV. — The above in optical section.

FIG. XV. — A twelve days' embryo of the same, from the left side. D. 2.

All from life, after treatment with 1 p.c. osmic acid. Figs. X. to XIII. after Lankester
(72). The cilia are exaggerated.

* This type is chosen on account of the facility with which its larvte can be obtained.

V

6,0

THE MUSSEL

PLATES XV., XVI.

THE MUSSEL.

63

PLATES XV., XVI.

THE MUSSEL.

a. Anus.

a.a. Anterior adductor muscle.*

a.a'. Nerve to the same.

a.ao. Anterior aorta.

a/. Albuminous fluid.

a.m. Adductor muscle.

a./). Posterior adductor muscle.*

a.p'. Nerve to the same.

au'. Right auricle.

ait". Left auricle.

b.d. Bile-duct.

b.d'. Aperture of bile-duct.

b.n. Branchial nerve.

l>r. Branchiie.

br.<i. Afferent branchial vessel.

br.a'. Afferent branchial trunk.

br.e. Efferent branchial vesse'.

br.e'. Efferent branchial trunk.

br.l'. Left outer gill lamina.

Irr.l". Left inner gill lamina.

Inj. Byssus.

bif. Byssus gland.

c.c. Supraocsophageal commissure.

c.ij. Cerebral ganglion.

e.p. Cerebro-pedal commissure.

<•./'.•«. Cerebro-splanchoic commissure.

e.s. Exhalent siphon.

/. Foot.

ij.a. Genital aperture.

;/.''. Genital duct.

ij.ijl. Genital gland.

</.*. Germinal spots.

(/.c. Germinal vesicle.

i. Intestine.

i.b.c. Infrabranchial chamber.

/..«. Inhalent siphon.

kb. Keber's organ.

/:/. Ligament.

Iji. Labial palps.

lp'. Artery to the same.

//'". Nerve to the same.

Iv. "Liver."

in. Month.

me. Micropyle.

na. Nacreous layer.

nc. Nucleus.

<e. (Esophagus.

l>.a'. Right anterior pallial artery.

p.a'. Left posterior pallial artery.

ji.no. Posterior aorta.

p.ao'. Posterior aorta of right side.

p.ao'1. Posterior aorta of left side.

lie. Pericardium.

/"I. Pedal ganglion.

pd.a. Pedal branch of anterior aorta.

/it. Cells of embryonic mantle.

]>l '. Right pallial lobe.

ji.in. Pallial muscle.*

ji.n. Pallial nerve.

]>o. Periostracum.

p.p. Protractor pedis muscle.*

/;/•. Prismatic layer.

p.s. So-called parieto-splanchnic ganglia.

l>.r. Efferent pallial vessels.

r. Rectum.

r'. Its cut edge.

re. Glandular portion of excretory organ.

re'. Nonglandular vestibule of excretory organ.

re". Renal aperture (or style passed into the

same).

re.c. Interrenal aperture.

re.ji. Reno-pericardial aperture.

r.m'. Anterior retractor muscle.

r.m". Posterior retractor muscle.*

r.m'''. Lesser retractor muscle.*
r.v. ' Afferent renal vessel.

r.v'. Efferent renal vessel.

*. Valves of shell.

s'. Inturned edge of shell.

x.l>.<-. Suprabranchial chamber.

Note. — The references marked thus, :;:, refer in Fig. III. to the crests of attachment of these muscles.

ATLAS OF BIOLOGY.

s.n. Siphonal nerve.

st. Stomach.

tc. Tactile organs of larva.

ty. Typhlosole.

M. Umbo.

v. Ventricle.

va'. Right auriculo-ventricular valve.

va". Left auriculo-ventricular valve.

v.c. Central blood sinus.

v.m. Vitelline membrane.

vs. Visceral branch of anterior aorta.

PLATE XV.

.

. .

TIIK MUSSEL. 65

PLATE XV.

THE FRESH-WATER MUSSEL. — THR EXTERNAL CHARACTERS AND THE SHELL. THE
ALIMENTARY AND EXCRETORY ORGANS. THE HEART, ETC.

FIG. I. — The living animal drawn from the left side, as seen in a deep, laterally com-
pressed glass vessel half filled with sand, the surface level of which is represented by a
transverse line.

The arrows indicate the course of the induced ciliary currents.

FIG. II. — The same, seen from behind.*

FIG. III. — The right valve, from within.

If carefully dissected from the body under water, it will be seen that the superficial
chitinous layer is continuous on the haemal side, between the points i. n., and also for
the area marked s'., where it is turned in and reflected on to the pallial muscle. (Compare
the transverse sections figured on Plate XVI.)

FIG. IV. — Dissection from the side, the left valve and pallial lobe alone removed.

The cut edge of the mantle is specially shown, as it indicates the line of attachment of
the gills and labial palps, and consequently that of demarcation between the supra and infra-
branchial chambers.

In the specimen figured the external gill lamina was fully distended with embryos.

FIG. V. — The same, dissected to the level of the alimentary canal ;f this, the pericar-
dium, heart, and aortae, have all been opened up.

The labial palps were cut down to the level of the middle line.

In this figure the suprabranchral chamber, incompletely subdivided by the suspensory
ligament of the branchiae, is also seen (compare Figs. VII. and VIII. of Plate XVI.)

(Figs. I. to V. all nat. size.)

FIG. VI. — The excretory organ, dissected from the left side, shortly after death.

The left half of the mantle-lobe was first removed as for Fig. IV., and after that the
greater part of the outer, and a small portion of the outer wall of the inner gill laminae, — as
indicated by their cut ends drawn. The genital and excretory apertures being thus exposed,

* The larger tentacles of the inhalent siphon are undoubtedly sensory, and I have witnessed the ejection of embryos
through the pore marked *, first figured and described by Keber (70). Compare Figs. IV. and V.

f If any difficulty is experienced in following tho coils of the alimentary canal, it can bo overcomo by first injecting
with plaster of Paris. This method should, however, be used with caution, as the parts are liable to be unnaturally-
distended.

9

66 ATLAS OF BIOLOGY.

the left half of the pericardium was removed, and the auricle of that side reflected. The
excretory organ was then opened up from the side, and its contained excreta gently washed
away, x 1^.

The fold seen embracing the genital and excretory orifices is derived from the lower lip
of the genital aperture.

The mussel is at all times best dissected in its shell, but if otherwise, pins should be
preferably passed through the adductor muscles. If, with the animal thus quite rigid, the
above directions are closely followed, there can be no difficulty in following the relations of
the excretory organ, provided it is clearly remembered that that organ is altogether outside
and below the pericardium. (Compare Fig. VII., and also Figs. VI. and VII. of Plate XVI.)

FIG. VII. — Dissection of the pericardium and excretory organ from above.

The roof of the pericardium was cut awav, the auricles in part removed, and the rectum
reflected. On the left side the floor of the pericardium and the roof of the excretory
vestibule, r&. (confluent in life), have been removed ; the point at which this is most obvious
indicates the interrenal aperture.

The limits and relations of the organ of Keber are shown, and the anterior aorta has
been opened up on the right side.* Nat. size.

FIG. VIII. — The heart in situ, laid open from above.

The greater part of the roof of the ventricle and of the auricle on the left side have
been removed, to the level of the auriculo- ventricular valve, * 3.

The student must not be misguided by the apparent anomaly in the passage of the
alimentary canal through the heart ; for be it remembered that in most animals, at one
.period or other of their existence, the two things are closely related.

* I cannot satisfy myself that the supposed communications between the blood- vascular system and the pericardium
—first described by Keber (70)— have any real existence. They appear to me to have been the products of undue
pressure used in injecting, and my own observations are entirely in harmony with those of Cattie (68) and Lankester (74),
and opposed to those of Griesbach (65).

PLATE XVI.

y--

THE MUSSEL. 67

PLATE XVI.

THE MUSSEL.— ORGANS OP CIRCULATION. THE NERVOUS SYSTEM. THE EMBRYO, ETC.

FIG. I. — The arterial system, seen from the right side, after injection from the ventricle.

With the exception of a small anterior portion marked *, the right pallial lobe has heen
removed, and with it the gills of that side. The pericardium was opened up, and the
mesosoma removed to the level of the alimentary canal. Nat. size.

FIG. II. — The efferent pallial, efferent branchial and related vessels, seen from the
left side after injection from the auricle.

The efferent branchial trunks are drawn, as seen after removal of the mantle, and no
note is taken of the extensive system of pallial sinuses connected with the trunk, br.e'.
Nat. size.

FIG. III. — Dissection from the right side, to show the great veins in relation to
the excretory organ.

The mantle lobe was removed, and the external gill lamina opened up.

The afferent branchial trunk and its branches, and the so-called vena cava were injected
direct, after removal of the right auricle.

For further details see Langer (71).

Fleming (64) records some observations upon the blood corpuscles and lacunae of this
animal, together with an ingenious method of injection. Nat. size.

FIG. IV. — Slightly diagrammatic representation of a transverse section across the
middle pericardial region, after injection, x 1|.

The channels shaded lightly, with the exception of that adjacent to the letter/., are
those carrying the aerated blood, x 11.

FIG. V. — Transverse section across A. of Fig. VI. of Plate XV., seen from the front,
to show the relations of the adductor muscle to the valves, and of the labial palps to the mouth.

FIG. VI. — Transverse section across B. of the same, the excretory and genital ducts
having been opened up on the left side.

FIG. VII. — Transverse section across C. of the same, passing through the auriculo-
ventricular valves and the great aperture of communication between the supra and infra-
branchial chambers.

FIG. VIII. — Transverse section across D. of the same.

68 ATLAS OF BIOLOGY.

FIG. IX. — Oblique transverse section across E. of the same, to show the so-called
liver, the main bile-ducts, and the relations of the lesser retractor muscles.

The above sections were made from a fresh specimen, some few hours after death.
All x ij.

FIG. X. — The nervous system, dissected from the left side, only such additional parts
being indicated as are concerned in ascertaining its course.

The pallial lobe and gills were removed, the excretory organ of the left side was slit
open, and its contents washed out.

The cerebral ganglia having next been found, the body-wall, liver, and genital gland
were in part removed as indicated — cutting in a line with the tendon of the protractor pedis
muscle, in order to expose the whole course of the cerebro-splanchnic commissure, c.p.s.
Nat. size.

The so-called parieto-splanchnic ganglia of the Lamellibrancli have been shown by
Spengel (81) to represent the olfactory ganglia of other molluscs.

FIG. XI. — Oblique transverse section across the oral region of Fig. X., to show the
relations of the supraoesophageal nerve-commissure, the pedal ganglia, and, on the left
side, • the whole course of the cerebro-pedal commissure.

The valve and labial palps of the left side were for the most part removed, the origins
of the tendon of the anterior pedal muscles being shown incidentally. Nat. size.

FIG. XII. — Ciliated and other cells, scraped from the lining membrane of the intestine.
The two lower ones were active in the production of a secretion. D. 3.

FIG. XIII.— Three ovarian ova, at different stages, teased out in eosin solution. D. 3.
The protoplasmic filament passing through the micropyle, me., represents the torn neck
of attachment to the germinal epithelium. See Von Jehring (67).

FIG. XIV.— Transverse section of the valve, cut at right angles to its long axis.
Prepared as described for the Crayfish shell (Plate X., Fig. VIII.) A. 3.

FIG. XV.— Tangential section across the prismatic layer of the same. D. 2.

FIG. XVI.— The GlocUdmm larva, from the gills of an animal killed under chloroform.
Spirit material, stained with magenta.

FIG. XVII.— The same, seen from the left side.
The dots on the valve represent pore canals.

PLATE XVII.

1 ... a.-.., „„•

THE HYDRA. 69

PLATE XVII.

THE HYDRA.

FIG. I. — The green Hydra, at the maximum of contraction and elongation of its body.
The animal is drawn in the act of seizing a small Cypris, marked *. A. 2.

FIG. II. — The same, looked at from above.

FIG. III. — The above, with the hypostome everted.

In this specimen two young tentacles were just appearing, the numerals i. to v.
indicate the order of development of these organs. Compare Jung (90).

FIG. IV. — Transverse section across the body of a Hydra, in the digestive cavity of
which a small crustacean was present.

At * are seen the remnants ot the digestible parts of that organism, not yet assimilated.
Hydra fusca. A. 4.

FIG. V. — Outline sketches of portions of two sections across the body of the same
animal, showing the variable extent to which the central cavity may be obliterated by the
amoeboid activity of the endoderm cells.

At d. a diatom is seen, bodily ingested. H. fusca. A. 4.

The most recent researches upon this intracellular digestion in the Hydrozoa, are
those of Lankester (95). A paper on the subject generally, by Mentschnikoff, will be
found in vol. xxiii. of the same journal.

FIG. VI. — A small portion of one of the tentacles, in the contracted condition. Surface
view. D. 2.

FIG. VII. — The same in elongation.

In both these figures, only the nematocyst-bearing cell aggregates are shown.

The small nematocysts, alone drawn in Fig. VII., are fixtures.

FIG. VIII. — The same, contracted under the influence of an irritant (1 p.c. acetic acid )
The larger nematocysts are drawn as observed to become everted. They stain very
readily with magenta solution. D. 3.

FIG. IX. — The leading types of thread-cells, drawn after liberation from the body.

i represents the functional, and ii the resting condition of the larger nematocysts ; in
i, the nucleated mass at the base and the fragment marked * represent the remains of the
parent cell.

70 ATLAS OF BIOLOGY.

iii. A younger example of the same, everted.
iv. The small fixed nematocysts.

v. The resting and active conditions of a third variety. The filaments of these stain
very deeply with magenta. All drawn to same scale. F. 3.

Hartog (87) has accounted for the occasional presence of thread-cells in the endoderm.

FIG. X. — Small portion of a transverse section across the hody of a green Hydra.
Picric acid, alcohol, borax carmine.

The cilia are drawn from an osmic acid preparation. (See Parker 97.) D. 3.

FIG. XI. — Isolated examples of the chlorophyll-bearing bodies of the same. Teased
up fresh in water. Gundlach's j^th immersion.

FIG. XII. — A small portion of a similar section to Fig. X., with a piece of the support-
ing lamella, c.L, seen en face.

Neither interstitial tissue nor endoderm cells are drawn. H. fusca. Osmic acid. D. 3.

FIG. XIII. — Larger cells of the ectoderm, isolated by bichromate of ammonia. F. 3.
FIG. XIV. — Cells of the interstitial tissue, treated in the same manner.*

FIG. XV. — The greater portion of a solitary endoderm cell from H. fusca, isolated.
Picric acid, and borax carmine. F. 4.

FIG. XVI. — One of the sooty-particle bearing portions of the same. Gundlach's ix6th
immersion.

Lankester (94) has suggested the most recent interpretation put upon these bodies,
and has finally set at rest the real nature of the chlorophyll-bearing bodies of H. viridis,
referred to above. The facts set forth in his paper have a most important bearing upon
the probable unity of the green and brown Hydra.

FIG. XVII. — A large brown Hydra, bearing at the same time asexually produced buds
and sexual organs. A. 2.

FIG. XVIII. a testis, and XIX. an ovary of the above, at a later stage of develop-
ment.

FIG. XX. — Outline sketches of portions of two brown Hydra.

The left one bore three ovaries, two of which are figured. The right-hand one bore
nine testes, of which four are figured.

This drawing does not by any means represent the maximum development of the male
organs, but it suffices to show that the testes need not necessarily appear only at the bases
of the tentacles.

* I am strongly of opinion that these often form syncytia.

THE HYDRA. 71

FIG. XXI. — The ovum of Fig. XVII., liberated under geiitle pressure. D. 2.

FIG. XXII. — Two ripe spermatozoa from the same. F. 4.

FIG. XXIII. — The ovum, at a late stage of segmentation, still enveloped in its
membranes. D. 2.

The sexual reproduction of Hydra has long been a vexed question; the last contribution
to the subject is that of Korotneff (92).

al. Digestive (body) cavity.

bl. Mouth (blastopore).

e. Cilia.

d. Chlorophyll-forming bodies.

cl'. Chlorophyll corpuscles.

c.l. Supporting lamella.

c.p. Kleinenberg's fibres.

(/. An ingested diatom.

ec. Ectoderm.

ec'. Larger ectoderm cells.

cc". Smaller ectoderm (interstitial) cells.

en. Endoderm.

e.s. Egg shell.

/. So-called foot.

ij.t. Germinal spots.

!/.r. Germinal vesicle.

li/i. Hypostomo.

nc. Nucleus.

ne. Nematocysts (various).

ne'. Larger uematocysts, before rupture.

or. Ovary.

UK'. Ovum.

jis. Pseudopodia.

f Tentacles.

('. Young (last formed) tentuclus.

t». Testis.

vc. Vacuole.

cc'. Amyloid vacuole of endoderm cell.

ij.ij. Yolk granules.

PLATE XVIII

xxvu

THE UNICELLULAR ORGANISMS. 73

PLATE XVIII.

THE UNICELLULAR ORGANISMS.

Vorticella.

FIG. I. — A group of Vorticellae, showing the animal in various positions. A. 3.
For a summary of the numerous species of this prolific genus see Kent (113).

FIG. II. — The same animal, in the extended and retracted states. Surface views.
FIG. III. — Another individual, drawn in optical section during the process of extension.

FIG. IV. — Two views of the same. In the right hand one (erroneously lettered
Fig. III.) a series of food vacuoles are drawn, one of them in the act of being ingested.

The arrows indicate the course taken by these, and the top left-hand one marks the
point at which egestiou most frequently takes place.

The left-hand figure represents the nucleus, after treatment with acetic acid and
magenta.

(Figs. I. to IV., all drawn under Zeiss. D. 4.)

FIG. V. — The initial phase in the process of multiplication by fission.
Two hours later, two equal-sized organisms resulted from this.

FIG. VI. — An example in which two individuals, unequal in size, resulted from the same
process.

The smaller one was drawn in the act of liberating itself.

FIG. VII. — The same, after liberation.

FIGS. VIII. and IX. — Two successive phases observed in the process of conjugation.

FIG. X. (Erroneously lettered IX.) — An encysted Vorticella.
(Figs. V. to X. all drawn under D. 2. The cilia are represented only in VI. and VII.)

Amoeba.

Figs. XI. to XVIII. represent successive phases in the life-history of an Amoaboid
organism, kept under constant observation for three days. See Appendix I.

XI. — The locomotor phase.

At * the ectoplasm is seen in the act of protrusion to form a pseudopodium, the
endoplasm passed into it later and quite suddenly.

10

74 ATLAS OF BIOLOGY.

XII. — A period in the ingestive phase.

The animal was observed to move round the glassy fragment figured *, for a period of
twenty minutes, finally rejecting it in favour of the small vegetable organism, f.p. ; in all
probability, any nutritive matter which may have been adherent to it was meanwhile
taken up.

XIII. — A portion of Fig. XII., after the organism,/.^., had been ingested.

XIV. AND XV. — Successive stages in the assimilative and excretive processes ; XV.
was drawn 19 — 20 hours later than Fig. XIII. The digestible parts of the ingested
organism were assimilated by the Amoeba, and the refuse ejected, as figured, in a distorted
disintegrating condition.*

The contractile vacuole. c.v., is drawn in Fig. XV., at both systole and diastole.

Engelmann (103) has made some observations upon the physiology of this organ.

XVI., XVII., XVIII. — Successive stages observed in the reproductive process of the
same organism, two days later. XVI. represents the nuclear-division stage, and the two
remaining figures are phases in the division of the cell.

The organism figured above was a small Amoeba having a conspicuous nucleus, found
in the sediment from a small fresh-water aquarium. Its probable specific identity is
left an open question, and the observations of Wallich (125) show how far such a determina-
tion might be reliable upon purely external appearances.

Gruber (107 to 110) has recently entered upon investigations of the greatest value,
concerning both this subject and the behaviour of the nucleus among unicellular
animals.

FIG. XIX. — A similar organism, encysted.

Three or four hours later the cyst disintegrated, liberating the animal.
(Figs. XI. to XIX. all drawn under Zeiss. D. 3.)

The Protococcus.

Figs. XX. to XXII. represent successive stages observed in the life-history of
Protococci, scraped from the bark of a tree.

A somewhat similar difficulty arises here as with Amoeba, with reference to the specific
identity. The latest paper on the subject is that of Klebs (114).

XX. — A group of organisms in the dried state.

The three stages in division figured, were observed in one individual.

- The appearances presented were such as to presuppose a digestive action on cellulose.

THE UNICELLULAR ORGANISMS. 75

XXI. — Oue of the same, after two or three days' iinmersiou in water under the
microscope.

XXII. — Later phases in the motile stage assumed by the above.

The black spot indicates the red colouring-matter present, and the extreme left-hand
figure is that of an individual destitute of cellulose investment. (Bergh, Morph. Jahrb.,
vol. vii., 1881, has discovered a cellulose investment for certain chlorophyll- bearing
Protozoa.)

The Yeast Plant.

FIG. XXIII. — Cells of ordinary brewer's yeast,
i.-iv. Stages in division of the same cell. D. 4.
i.a Fig i. as seen under Gundlach's iJ5th immersion,
v. A branching colony, still retaining their original connections.

Schmitz, Stzb. Bonn, August, 1878, has described in the yeast-cell, and in certain other
low organisms, Mucor among their number, what he considers to be a nucleus.

FIG. XXIV. — The endogonidia (ascospore) phase of reproduction, as seen in a sample of
yeast sown on a slab of gypsum. F. 3.
See Huxley (111) and Bees (120).

FIG. XXV. — Further development of the endogonidia, after transfer to Pasteur's
solution. F. 3.

The Bacteroid,
FIG. XXVI. — Micrococcus.

FIG. XXVII.— Bacterium.

FIG. XXVIII. —Bacillus.

The central filament of this series segmented up, as drawn, within ten minutes of its
detection.

FIG. XXIX.— Spirillum.

i., ii. represent the so-called Vibrio. It is probably but a stage of Spirillum.

FIGS. XXX. and XXXI.— Two giant Spirilla.

FIG. XXXII. — A drop of the surface scum, showing a Spirillum aggregate in the
resting state.

70

ATLAS OF BIOLOGY.

FIG. XXXIII. — The so-called spore-forming stage in Spirillum.

The specimen segmented up as indicated, while being drawn.

Brefeld (99) gives figures of the germination of the so-called spores of Bacillus, drawn
at recorded intervals of time.

All the above Bacteroids were observed in some hay-infusion, allowed to stand two
days in a warm room. They are all — with the exception of Fig. XXXII. — drawn to the
same relative scale, as viewed under Gundlach's y^th immersion.

Dallinger (102) has demonstrated the presence of cilia in the motile stages of Bacterium
and Bacillus.

b. Bud.

c. Cyst.

c.f. Contractile fibre,

c/. Cilium.

cl'. Posterior ring of cilia

c.w. Cell-wall.

d. Disc.

dt. Ingested diatom.

eg. Endogonidia (ascospores).

/. Fat drops.

f.p. Food particle.

nc. Nucleus.

we'. Nucleolus.

p. Peristome.

ps. Pseudopodiuru.

sp. So-called spores.

sp'. Encysted spore-like masses.

v. Vacuole.

v.c. Contractile vacuole.

v.J. Food vacuole.

rs. Vestibule.

PLATE XIX

.ah.

XXVII

XXIII

THE FUNGI. 77

PLATE XIX.

THE FUNGI.

Mucor mucedo.

FIG. I. — Spore-bearing hyplue of inucor, as seen iii life, standing out from a piece ot
horse-dung.

FIG. II. — A small portion of the same fungus, teased out with needles. A. 4.

FIGS. III., IV., V. — Successive stages in the development of the sporangium.

IV. is represented in optical section.

V. A ripe sporangium crushed under pressure (the mucilaginous fluid, me., is represented
too darkly).

The small figure to the right is one of a portion of V. in optical section.

FIG. VI. — The central columella of the above.

(Figs. III. to VI. all D. 2.)

FIG. VII. — Isolated spores of mucor.

FIG. VIII. — Germinating spores of the same.

FIG. IX — i. to vii. successive stages in the germination of a single spore.
Only a portion of vii. is drawn.
Object glass culture, see Appendix I.

(Figs. VII. to IX. all D. 4.)

FIG. X. — The product of twenty-four hours' growth from a single spore, itself indicated
as a slight enlargement.

Object glass culture. A. 3.

FIG. XI. — A chlamydospore — bearing hypha of the same. One spore is seen breaking
away. D. 4.

FIG. XII. — The torula stage of Mucor, from a growth kept submerged in a saccharine
solution. D. 4.

See Max Bees (120) and Huxley (111).

FIGS. XIII., XIV., XV. — Successive phases in the conjugative process of Mucor.
From Brefeld (128).

78 ATLAS OF BIOLOGY.

Penicillium glaucum.
FIG. XVI.— A small portion of the crust of Penicillium in transverse section. A. 2.

FIG. XVII. — A piece of the above, teased up.

i., ii. Two adjacent conidia. For further varieties see Brefeld (129). D. 4.

iii. One series of stylo-gonidia of the same, more highly magnified. F. 3.

FIG. XVIII.— Successive stages. observed during one day's (10 hours) growth of a coni-
diophore of Penicillium.

Object glass culture. D. 4.

FIG. XIX. — A group of germinating Penicillium spores.
Object glass culture. D. 2.

FIG. XX. — The same, sixty hours after sowing. A. 2.

FIG. XXI. — Isolated spores of this fungus.
Many are germinating. D. 4.

FIG. XXII. — Successive phases in the germination of a single spore. D. 4.
FIG. XXIII. — Phases in the conjugative reproduction of Penicillium.

FIG. XXIV. — Germination of one of the ascospores, produced as the result of con-
jugation.*

[Figs. XXIII. and XXIV. after Brefeld (129).]

Aspergillus,

FIG. XXV. — Spore-bearing hypha of this fungus, from a slice of bread exposed to a
warm moist atmosphere for 15 days. D. 3.

FIG. XXVI. — The conjugative phase of the same.

Obtained by teasing up the yellow portions of the fungus, grown as above. The hypbas
marked * are two last developed ones of a great number (not drawn) which formed the
investing peritheca, the limits of which are indicated by a dotted line. D. 4.

FIG. XXVII. — Portion of a spore-bearing carpogonial hypha of the above, at a later
stage. F. 3.

[Figs. XXV. to XXVII. from life, after de Bary and Woronin (126).]

* The chances of the student's obtaining a cultivation of the conjugative phase of this fungus being but slight, the
Eurotium stage of aspergillus is supplemented, as it can be readily obtained.

THE FUNGI.

a. ABCUS.

ax. AFCospore.

r.h. Carpogonial hypha.

rl. Columella.

I-.H. Nutritive branch of carpogonial liypbn.

cj>. Carpogonium.

cs. Chlamydospore.

c.s. ASCIIS forming branch of carpogonial byphn.

en. Endogonidia (ascospores).

ex. Exosporinro.

h.a. Aerial hyphw.

h.*. Submerged hjrpliir.

li.nt. Sterile hyphtr of sclerotinm.

>««•. Mucilage.

my. Mycelium.

/'/. Pullinodinm.

«/. Sterigma.

KJI. Sporangium.

xt. Stylogonidin.

si/. Zygospore.

PLATE

\-V.i

THE STONEWORTS. 81

I PLATE XX.

THE STONEWOKTS.

FIG. I. — An entire actively-growing plant of Chara.*

Growth at the summit was making good disintegration and death at the base,
resulting in a separation between the main and the oldest lateral axes, as figured.
The rhizoids are indicated for but one node. Nat. size.

FIG. II. — The same, from internode 5 — 6 upwards.

The appendages of whorls 2 to 4 were slightly displaced, to render visible the apex.
* 8.

One segment of the descending cortical lobe has, in the case of two internodes and of
two lateral axes, been shaded darkly. The pails lettered n.c. represent one cortical node.

Only one lateral bud is drawn, ax'., and no note is taken of the fruits.

FIG. III. — Median longitudinal section through the terminal bud of a similar plant.

The growing apices are left white, and the nodal and cortical elements are shaded
darkly. D. 3. Osmic acid and alcohol. See Parker (137).

The arrows indicate the directions of growth of the cortex.

The nuclei of the old cells are not drawn, being in the condition described by Stras-
burger (142) as fragmentary. See also Johow (135).

FIGS. IV. to VII. — Four teased preparations of dividing apical cells, preserved as for
Fig. III.

As drawn, they represent in order four successive phases in the developmental history
of the growing apex.

The sub-apical (segmental) cell is, in Fig. VI., and its products are in Fig. VII., shaded
darkly. D. 3.

FIG. VIII. — A fertile leaf of Nitella, bearing both male and female organs.
Seen from the side. A. 3.

FIG. IX. — A similar leaf, bearing female organs alone. Seen from above. A. 3.

* A synopsis of British Characeoi will be found in Groves (184).

11

82 ATLAS OF BIOLOGY

FIG. X.— A. fertile leaf of Chara, viewed from the same aspect and drawn to the same
scale as that of Nitella, Fig. VIII.

FIG. XI. — One set of reproductive organs from the same, magnified. A. 3.

FIG. XII. — The apex of the carpogonium of Nitella.

FIG. XIII. — The same in Chara, looking down on the micropyle.

FIGS. XIV. and XV. — Two stages in the development of the reproductive organs of
Chara, in section. From nature after Sachs.

(Figs. VIII., X., XI., XIV., and XV., are all drawn in the same position relative to the
axis.)

FIG. XVI. — One antheridial shield of Chara, with its male reproductive apparatus.
An immature example, crushed. D. 2.

A few segments of a ripe antheridial filament are drawn below, and to the right one
antherozooid, liberated by pressure. F. 3.

FIG. XVII. — The above antheridial shield, etc., seen from within. All the filaments
are represented. A. 3.

FIGS. XVIII. and XIX. — Two stages in the growth of the pro-embryo ; the older one
shows the origin of the young plant arising from it, — set free by disintegration of the
pro-embryo, as the lateral axes are liberated by that of the adult plant. (Compare Fig. I.)

[For further details and a full bibliography, see Sach's " Text Book of Botany," and
Luerssen (136).]

a. Anthcridium.

a'. Mother cell of the same.

a.e. Axis of young plant.

«./. Antheridial filaments.

a./'. Parent cells of the same.

a/i. Apical cell of axis.

ap'. Apical cell of pro-embryo.

o.x. Antheridial shield.

ax. Main axis.

ax'. Lateral axis.

at. Antheridial filament, cells of.

iiz'. Mature antherozooid.

fr, Bracteole.

I.e. Basal cell cf reproductive organ

c. Cilia.

c.y. Chlorophyll granules.

c</. Carpogonium.

c.l'. Ascending cortical lobe.

c.l'. Descending cortical lobe.

cj>. Capitulum.

<-•}>'. Secondary capitula.

cr. Crown of carpogonium.

c.s. Carpospore.

ct. Cortex.

i.e. Investing cells.

in. Internode.

in. a. Last formed internode.

in.r. Cortical internode.

THE STONE WORTS.

/. Leaf.

/'. Leaflets.

/". Sterile leaflets.

I. a. Apical cell of leaf.

HI. Manubrium.

me. Hicropyle.

7i. Node.

n.a. Last formed node.

n.c . Cortical node.

»c. Nucleus.

n.li. Leaf-bearing node of pro-embryo.

n. r. Root-boaring node of the same.

or. Oosphero.

»•. Primary root.

rli. Rootlets (rhizoids).

K.II. Seginental cell.

re. Sap vacuole.

1 to 5. Nodes or their appendages, 1 to 5.

i. to v. Internodes.'i. to v.

THE FERN

PLATES XXI., XXII.

THE FERN.

N7

PLATES XXI., XXII.

THE FEEN.

a. Archegonium.

a . Neck of the same.

ii.fi. Apical cell.

tin. Anniilus.

up. Growing apex of stem.

a/*'. Growing apex of leaf.

at. Antberidium.

at'. Parent cell of the same.

az. Parent cells of antherozooids.

h.c. Basal cell.

c. Cilia (for Fig. XIII. PI. XXII. Cushion).

ca. Ventral canal cell.

t-a'. Central cell of neck.

c.e. Central cell.

cl. Chlorophyll grains.

cl. Cotyledon.

/. So-called foot.

i. Indusium.

i.e. Investing cells of sporangium.

;..i. Intercellular space.

/. Leaf stalk (rachis).

/'. Leaflet.

l.li. Lateral bud.

/./. Lateral line.

nix. Mesophyll.

nc. Nucleus.

n.c. Dividing neck cell.

or. Oosphere.

p. Pinna.

l>c. Parenchyma.

pc'. Conjunctive parenchyma.

p.p. Protophloem of Russow.

pt. Prothallus.

r. Roots.

r'. Root hairs.

r". Primary root hairs.

r/i. Rhizome.

r.j>. Primary root.

»d. Sclerenchyma.

scl'. Peripheral sclerenchyma.

id". Central sclerenchyma.

s;/. Ripe sporangium.

si/'. Young sporangium.

xh. Bundle sheath.

ah'. Phlrem sheath.

«/>. Spores.

up'. Spore mother cells.

*./>. Sieve plate.

*{. Stoma.

s.t. Sieve tube.

tc. Trichomes.

tji. Tupetum.

nt. Protoplasmic utricle.

v.b. Vascular buudlc.

v.b'. Peripheral bundles.

v.b". Central bundles.

re. Vacnole (cell sap).

xy'. Protoxylem vessels.

xij". Scalariform vessels (secondary xylem).

OS B Hcwoe d«l ad n«.t .

THE BRACKEN FERN. K'J

PLATE XXI.

THE BEACKEN FERN. — EXTERNAL CHARACTERS. THE ANATOMY AND HISTOLOGY OF THE

VEGETATIVE ORGANS.

FIG. I. — A fern plant, carefully washed after removal from the earth.

The transverse dotted-line indicates the level of the soil, the leaf of the current season
ii. alone rises above it, and of those parts beneath it i. represents the leaf next to reach the
surface, and iii. the disintegrated base of that of last season. $ nat. size.

The arrows indicate directions of active growth.

FIG. II. — One node of a fern plant, from which a second leaf has been developed in one
season.

i. The past, ii. The current, iii. The young frond. J nat. size.

FIG. III. — Transverse section across an internode of the rhizome at its thickest part.
The roots are not indicated.

FIG. IV. — Longitudinal section through an internode, at right angles to the lateral line.
It passes through the base of a lateral root.

. v. — A transverse section across the youngest node, passing throiigh the axis of a
young leaf.

The smaller sclerenchyma tracts are not indicated.

(Figs. III. to V. all x 2.)

FIG. VI. — A portion of the rhizome, from which, after two days' immersion in alcohol,
the superficies tissues were scraped away to the level of the bundle system. Nat. size.

FIG. VII. _ Portion of a thin transverse section across the rhizome, sufficient being
indicated to take in one entire vascular bundle. A. 2.

The bundle sheath, the protophlcem of Eussow (138), and conjunctive parenchyma are
all shaded over.

FIG. VIII.— Portion of a transverse section of a vascular bundle, more highly
magnified. D. 4.

FIG. IX.— Portion of a radial longitudinal section of the rhizome, the same parts being
shaded as in Fig. VII. A. 2.

FIG. X.— Portion of a thin radial longitudinal section of a vascular bundle, passing
through the protoxylem. This, for the sake of distinction, has been shaded over.
All the vessels are here drawn as seen in surface view. P. 4,

12

!)0 ATLAS OF BIOLOGY.

No attempt has been made in any of the above figures to represent the starch present.
It will be found to vary in quantity with the season of the year.

Staining is unnecessary, but if resorted to, haematoxylin is preferable.

FIG. XI. — A typical cell of the parenchyma.

FIG. XII. — A cell from the sub-epidermal tissue.

Both of the above were teased up in eosin, from spirit material.

FIG. XIII.— A typical cell of the sclerenchyma.

FIG. XIV.— Portions of a protoxylem vessel.

Torn fragments of the thin, unlignified part of the cell wall are often visible, as at *.

FIG. XV. — A small scalariforrn tracheid, one portion of which is drawn in section.

FIG. XVI. — A small portion of the boundary wall between two scalariform tracheides,
highly magnified. Gundlach's j^th immersion.

FIG. XVII. — A sieve-tube.

(Figs. XI. to XV., and Fig. XVII., are all drawn to the same scale, and in XIV., XV.,
and XVII., the thickened parts of the cell walls are alone shaded. D. 4.

Figs. XIII., XIV., XV. and XVII. are drawn from cells isolated away under treatment
with nitric acid).

FIG. XVIII. — Portion of a sieve-tube from the fresh stem, treated with J p.c. osmic
acid.

The protoplasmic connections figured are inserted from De Bary (132). Gundlach's
TT5th immersion.

FIG. XIX. — Median longitudinal section through the apex of the rhizome.
The apical mass of indifferent tissue which graduates off into the several constituents
of the stem, is shaded darkly. A. 2.

FIG. XX. — A portion of the above highly magnified, showing the apical cell, and the
two cells of the indifferent tissue last cut off from it. Of these, the older had subsequently
divided up. D. 4.

FIG. XXI. — Transverse section across a similar apex. Details as for Fig. XX. D. 4.

PLATE XXII.

»«•

ItCo imi.

THE BRACKEN FERN. 1)1

PLATE XXII.

THE BRACKEN FERN.— THE LEAF, REPRODUCTIVE ORGANS, AND DEVELOPMENT.
FIG. I. — Portions of the same leaf, seen from beneath, x 2.

FIG. II. — Section across the plane a-b. of one pinnule of the above. D. 2.
The chlorophyll-bearing cells are alone shaded.

FIG. III. — Similar section across the margin of a sterile leaf. D. 2.

FIG. IV. — A similar section across the margin of a spore-bearing leaf. D. 2.

FIG. V. — A young sporangium from the above, in optical section.

FIG. VI. — A ripe sporangium from the same. Surface view.

FIG. VII. — A similar sporangium after rupture under pressure.

The right hand portion of the figure, indicated in outline, represents the result of
rupture under imbibition of water.

(Figs. V. to VII. D. 3.)

FIGS. VIII., IX., X. — Early stages in the germination of a fern-spore, grown on a slab
of limestone in a warm damp atmosphere. (The outside of a flower pot answers very
well). D. 4.

No trace of chlorophyll was yet visible.

FIG. XI.— A later stage of the same.

The developing prothallus, now quite green, was growing from an apical cell, ap.
i. to iii. indicate the last formed cells of the apex. (Compare Figs. XX. and XXI. of
Plate XXI.) D. 4. \ p.c. osmic acid.

FIG. XII. — One cell of Fig. XL in detail, viewed in optical section. F. 2.

FIG. XIII. — A sexually mature prothallus, viewed from beneath.

The archegonia are indicated in black, and the antheridia are left white, * 10.

FIG. XIV. — A portion of the same near the edge of the cushion, highly magnified.
The antheridia are drawn focussed to the level of the dividing central cells, and the
detailed structure of the investing cells of both archegouia and antheridia is omitted.

FIG. XV. — An older autheridiuin.

92 ATLAS OF BIOLOGY.

FIG. XVI.— Another, after the discharge of the antherozooids.

(Figs. XV. and XVI. were near the margin of the prothallus. Figs. XIV. to XVI.
D. 4.)

FIG. XVII.— Section across the sexually mature prothallus, through the plane a- b, of

Fig. XIII.

The left half* of the figure represents three views of the unfertilized archegomum in
Aspidium, and the right half corresponding aspects of the antheridium in Pteris. In each
case they are —

i. The ripe organ, surface view.

ii. The same in section.

iii. The young organ, in section. D. 3.

No attempt has been made to fill in the detailed structure of individual cells. The
archegonia not unfrequently occur on the upper side of the prothallus as well as on the
under.

FIG. XVIII.— Three ripe antherozooids, after liberation under pressure.
i p.c. osmic acid. Gundlach's ^th immersion.

FIG. XIX. — The segmenting egg-cell of Asplenium.

After Schenk (139), vol. i., p. '217.

The first formed septa are indicated by a thick black line.

FIG. XX. — Section across an embryo-bearing prothallus of Nephrolepis, cut as directed
for Fig. XVII.* A. 3.

In Figs. XIX. and XX. homologous parts are shaded alike, and the arrows indicate the
directions of growth of the four subdivisions of the embryo.

* Marks the line of differentiation of the vascular bundle.

For Pteris, similar stages to the above have been figured by Hoftneister and others.
They are reproduced in Luerssen (136), vol. i.

See also Hofmeister's papers on the higher Cryptogams. Translated by F. Currey.
Bay 8oc. Publications, 1862.

FIG. XXI. — A fern-bearing prothallus, seen from beneath, x 8.

The central dark line indicates the bundle system, and the parts of the embryo are
shaded as for Figs. XIX. and XX.

* For the sections from which these were drawn I am indebted to my friend Mr. F. 0. Bower.

THE FLOWERING PLANT

PLATES XXIII., XXIV.

THE FLOWERING PLANT.

95

PLATES XXIII., XXIV.

THE FLOWERING PLANT.

a. Apex of main axis.

'('. Apex of root.

a.b. Axillary bud.

a.c. Air cavity.

an. Annular vessels.

afi. Antipodal cells.

ax. Main plumular axis.

a,r'. Hypocotyledonary stem.

ay". Main or primary root.

az. Pollen grains.

at' '. Mother cells of the same.

c. Cuticle.

eb. Procambium.

c//. Cambium.

eb". Pericambium.

Cji. Carpels.

rl. Cotyledon.

ft'. Base of attachment of the same.

e.w. Cell wall.

ex. Cortex.

e. Embryo.

«/. Bundle sheath (endodermis).

en. Endosperm.

en'. Parent endosperm nucleus (central nucleus

of embryo sac).

<7>. Epidermis.

<7/. Snbepidermis (collenchyma).

e.x. Embryo sac.

/. Funiculus.

ij.c. Guard cells.

!/l. Glandular hairs.

yr. Starch grains.

gr'. Aleurone grains.

». Integuments.

i.e. Intercellular space.

i.n. Internode.

/. Leaf.

me. Mioropyle.

md. Medulla (pith).

mil'. Pith cavity.

»i.r. Medullary rays.

mx. Mesophyll.

n. Node.

tie. Nucleus.

mi. Nucellus.

o. Ovule.

ov. Oosphere.

ay. Ovary.

fi. Mouths of pits.

/><: Parenchyma of cortex.

IH-'. Parenchyma of pith.

jilt. Phkem (Protophlcem, in Figs. XXtV. and

XXV., PI. XXIII.)

/'It'. Hard bast.

ph.r. Phloem rays.

/'/. Pallisade tissue.

ji.ji. Phloem parenchyma.

pt. Petals.

p.t. Pollen tube.

/).(-. Pitted vessels.

r. Secondary roots.

/•''. Lateral rootlets.

•s. Stoma.

xb. Subsidiary cells.

se. Sepals.

mj. Stigma.

*./. Spiral layer of anther.

am. Stamens.

xji. Spiral vessels.

«.]>, Sieve plate.

xt. Style.

s.t. Sieve tube.

*H. Suspensor.

«('. Basal cell of suspensor.

si/. Synergidse.

/. Testa.

tc. Trichomos.

tji. Tapetum.

ut. Primordial utricle,

r. Vacuole.

v.li. Vascular bundle.

.r.ji. Xylem parenchyma.

,ry. Xylem.

.nj. Protoxylem.

,ry". Xylem sclerenchyma.

xy.r. Xylem rays.

XXHI.

THE FLOWERING PLANT. 97

PLATE XXIII.

THE FLOWERING PLANT.— EXTERNAL CHARACTERS. THE VEGETATIVE Axis.

Unless otherwise stated, all the figures on Plates XXIII. and XXIV. illustrate the
structure of the French Bean plant, Phaseolus vulgaris.

FIG. I. — The entire seed, viewed from its attached surface, after a few hours' immersion
in water.

FIG. II. — The same, after removal of the testa.

FIG. III. — The same, after removal of the right cotyledon.
Seen from within.

FIG. IV. — A similar seed during germination, just on leaving the soil.
Grown in damp sawdust, the surface level of which is indicated hy the line i — ii.

(Figs. I. to IV. all nat. size.)

FIG. V. — A twelve-days' plant, grown as for Fig. IV.
The unlettered transverse line represents the surface level of the sawdust.
The arrows indicate the direction of growth of the original main axis.
The cotyledons, colourless in Fig. IV., were here quite green. \ nat. size.

FIG. VI. — Median longitudinal section through the embryonic axis of Fig. III.
The arrows indicate the direction in development of the procambium of oue lateral axis,
differentiation having commenced at the point marked by the adjacent line.

Picric acid and alcohol. Eosin stained, preserved in Canada balsam. A. 2.

FIG. VII. — A portion of the hypocotyledonary axis of the above. D. 3.
The several tissues figured, graduate into each other as the apex is reached.

FIG. VIII. — Section of a cotyledon of the above. F. 2. Fresh, stained cosin.

It is important to guard against mistaking cut corners of ceUs for intercellular spaces.

FIG. IX. — The apical cone of Fig. V. teased out with needles.

The internodes are shaded darkly. D. 3.

The apex of Anacliaris may profitably be teased up for comparison.

FIG. X. — Transverse section across the main root of Fig. V. Nat. size.

13

98 ATLAS OF BIOLOGY.

FIG. XI.— Median longitudinal section of the epicotyledouary axis of Fig. V. x 10.

FIG. XII.— Transverse section of the same, across the point marked *— * in Fig. V.
x 10.

FIG. XIII.— A similar section across the same axis of an older plant, x 5.
(In Figs. XI. to XIII. the cambium layer is represented as a black line.)

FIG. XIV. — The bundle-system of the French Bean, seen from the side. Dissected
as for the Fern, Fig. VI., Plate XXI. From nature, after Nageli. See De Bary (132).*
The bundles of the left side are shaded darkly, x 2.

FIG. XV. — Thin transverse section of a portion of Fig. XII.

The protoxylem elements, xy'., may often be at once recognized in transverse sections,
as the spiral or annular thickenings frequently tear away in cutting and hang ragged. D. 3.

FIG. XVI. — Kadial-longitudinal section of a similar stern, taken through the axis of a
young bundle. D. 3.

FIG. XVII. — Portion of a thin transverse section of Fig. XIII.

The phloem parenchyma and the rays of the vascular bundle are here shaded. D. 2.

In Figs. XV. and XVII., the trichomes are for the most part omitted, and no note is
taken of the chlorophyll present in the cells of the parenchymas.

The only structures in which the protoplasm is drawn, are the sieve tubes ; it is repre-
sented in them in the contracted post-mortem, state. (See below.)

FIG. XVIII. — Sections of the sieve tube in the above.
i. The protoplasm, drawn as in life.

ii. The protoplasm, drawn in the shrunken post-mortem condition,
iii. Portion of a sieve-tube bearing both transverse and lateral sieve plates. Iodine.
Gundlach's /gth immersion.

FIG. XIX. — A cambium cell, isolated under treatment with nitric acid, as for the fern-
stem, Figs. XIV., etc., Plate XXI. D. 3.

FIG. XX. — A similar cell, as seen in tangential section of the cambium layer. D. 3.

FIG. XXI.— -A dividing cambium cell, drawn from the layer, cb'., of Fig. XVI., as seen
in radial-longitudinal section. D. 3.

* Largo models of this and certain other bundle-systems, after Nageli and others, are made by H. Gasser, of the
Botanical Institute, Graz.

THE FLOWERING PLANT. 99

FIG. XXII. — A portion of an isolated pitted vessel, seen en face.

FIG. XXIII. — Section through the partition wall between two pitted vessels. Guud-
lach's th immersion.

FIG. XXIV. — Transverse section across i. — ii. of the main root of Fig. V., after harden-
ing in alcohol.

The section passed through a young lateral root. A. 2.

FIG. XXV. — The greater portion of the same, more highly magnified.*
No note is taken of the intercellular spaces. D. 3.

FIG. XXV." — The bundle-sheath of the above enlarged. Gundlach's ^th immersion.

* Sections such as this, to show the typical arrangement of the parts of the root, must be cut low down near the

apex.

1-M.ATK XXTV.

\

G.BJW,.., ,1.1 „,]„_

THE FLOWERING PLANT. 101

PLATE XXIV.

THE FLOWERING PLANT.— THE LEAF AND FLOWER. THE REPRODUCTIVE ORGANS,

AND DEVELOPMENT.

FIG. I. — Transverse section across the oldest leaf of a young bean-plant.
The whole leaf was rolled up and cut in the fresh state. D. 3.

FIG. II. — A portion of the epidermis of the same stripped off, showing the characters
and relations of the stoma and guard-cells, the subsidiary cells, and the trichoine. D. 4.

The glandular hairs arise as central cells of a series, similarly to the trichome
figured.

Examined fresh in water, the details of cell-structure being drawn after treatment
with 1 p.c. osrnic acid.

FIG. III. — Slightly diagrammatic representation of a developing stoma.
The entire parent cell is drawn, and the septa by which it was divided up are num-
bered i. to iii., in order of development ; iii. would have finally split to form the stoma.

The specimen figured was obtained from near the edge of a young leaf. Fresh. F. 3.

FIG. IV. — Section through a stoma of Fig. I. F. 4.

FIG. V. — Median longitudinal section of a Buttercup. x 3.

FIG. VI. — Similar section of a Beau-flower, * 2.

FIG. VII. — Transverse section of the anther of a nearly matured Buttercup. Alcohol
and weak glycerine. D. 2.

By cutting the whole flower-head between the finger and thumb, most instructive
sections may be obtained, cut at all possible levels.

FIG. VIII.— A small portion of Fig. VII., more highly magnified. F. 3.

FIG. IX. — Three pollen-grains, teased out from the stigma of an open Buttercup. (See
Fig. XL)

Taken in the order numbered, they represent stages in the development of the pollen
tube. Such stages may be obtained with ease, by object-glass culture in a saccharine fluid.
1 p.c. osmic acid. D. 3.

The smaller nucleus is stated by Strasburger (143) to be alone the active agent in
fertilization,

102 ATLAS OF BIOLOGY.

FIG. X.— Developing pollen-grains, from the anther of a young Buttercup. Teased.
F. 3.

FIG. XI.— Surface view of a thick longitudinal section, through the stigrua of an open
BiMercup.

The central shaded portion * represents the central cavity of the style. Alcohol and
weak glycerine. D. 3.

FIG. XII. — Slightly diagrammatic longitudinal section of the entire carpel of an open
Buttercup, at the period of fertilization.

This figure represents the facts, as pieced together from observations made upon a
number of sections, obtained as for Fig. VII.

* Indicates a single well-differentiated layer of cells, surrounding the central canal of
the style.

FIG. XIII.— Transverse section of the carpel of an unopened flower of Lilium, to show
the general relations of the ovules, etc.

The parts indicated in black represent the passage open to the pollen tube, when once
it has entered the central canal of the style. A. 2.

FIG. XIV. — An ovule from the same, more highly magnified. D. 2.

FIG. XV. — A similar section from the carpel of a much younger flower. D. 3.

FIG. XVI. — Three embryo sacs from the same carpel as Fig. XIII., to show the
changes undergone prior to fertilization. D. 2.

As numbered in order i. to iii. they represent successive stages in the development of
an individual. Figs. XIV. and XV. present still earlier phases in the same development.

The above sections (Figs. XIII. to XVI.) were prepared from fresh material, transferred
as cut into a half-and-half solution of methylated spirit and glycerine, and kept exposed in
a warm room until the spirit had evaporated.

FIG. XVII. — An ovule, teased up from the fruit of the Shepherd's Purse. A. 3.

FIG. XVIII. — The embryo drawn in Fig. XVII. i. liberated under gentle pressure.
D. 4.

FIGS. XIX. and XX. — Two embryos, teased from younger fruits of the same plant.
D. 4.

The three embryos above figured represent successive stages in development, and
only such are here drawn as can be readily seen with ease by teasing up the fruits with
needles.

For further details see Hanstein's figures, reproduced in all the text-books.

THE FLOWERING PLANT. 103

FIG. XXI. — A much older embryo of the same plant, at this stage quite green.

The curvature of the cotyledons becomes intelligible on considering the natural position
of the embryo, shown at ii. in Fig. XVII. In life, the cotyledon marked* overlay its fellow,
as indicated by the dotted lines in Fig. XVII., thus hiding the apex from view. A. 3.

FIG. XXII. — Median longitudinal section of the fruit of Potamogeton (the Broad Pond-
weed), to show the relations of the endosperm to the embryo. Alcohol and weak glycerine.
A. 2.

Each fruit of the above plant contains biit one embryo, and if, holding the fruits between
the finger and thumb, the sides are sliced away, most satisfactory preparations can be
readily obtained.

FIG. XXIII. — A portion of the above more highly magnified, showing the nuclei of the
endosperm, and the embryo in detail. D. 4.

The distinctive characters of the Monocotyledon embryo are here drawn, as compared
with those of the Dicotyledon represented in Fig. XXI.

A PPE N D IX

AND

BIBLIOGRAPHY

APPENDIX. 107

APPENDIX

A. The terms right and left are always used in anatomy, with reference to the right and left sides of the
subject's body. Similarly, by the anterior is always meant the head end, and by the posterior the hinder end.
The terms dorsal and ventral apply to the back and the belly respectively ; they are, however, often replaced
by terms bearing directly upon the position of the nervous axis, viz., neural and haemal for the vertebrate,
haemal and neural for the invertebrate.

B. The method of dissection from the side here employed has long been recognized as yielding results
second to no other, where a general survey of the animal's entire anatomy is required. Moreover, by cutting
thus to one side of the middle line, the attachments of the organs are not interfered with, and they, therefore,
remain in position for detailed examination.

In dissecting all the animals dealt with in this work, some such stand as that figured above will be found
useful; the rests for the arms may conveniently be lengthened to suit individual requirements, but the
swinging-arm, carrying a watchmaker's lens, will be found a necessity in examining delicate structures.

All dissections should be performed under water, with the subject in a perfectly rigid position. For this
purpose a dish, such as is here figured, is necessary; it should be preferably of glass, one-third filled with
paraffin blackened by the admixture of a little lamp-black. A slab of the above material admits of the
subjects being pinned down, and it should always be weighted at the bottom with lead, to avoid floating up.

Should the water become clouded in dissecting, it must be at once changed, the cause of the obstruction
being, if possible, washed away.

While dissecting, it is highly desirable that living specimens of the animal under consideration should be
kept constantly under observation, as -many a structural feature is only intelligible on a knowledge of the
creature's habits.

108 ATLAS OF BIOLOGY.

C. Whole animals, or dissections, are best preserved in alcohol. The ordinary methylated spirit of com-
merce, diluted with ^rd its bulk of water, answers admirably ; delicate structures, such as the brain, must be
placed at once into strong methylated spirit, and in all cases the preservative medium should be replaced after
the first twenty-four hours. With the above exceptions, it is not desirable to submit any preparation at once
to the action of strong methylated spirit, as such a course is apt to result in a too rapid dehydration of the
superficial parts, thus preventing that complete permeation necessary for successful preservation.

Where very careful preservation without shrinking is desired, it is well to use in succession, 50 p.c. for
twenty-four hours, 75 p.c. for the next forty-eight, methylated spirit ad infinitum, being careful to prevent the
access of air.

D. For ordinary coarse injection of the blood vessels, a mixture of French blue, in the proportions of a
teaspoonful to a tumbler of water, cannot be surpassed. It is cheap, sufficiently finely divided to enter
all but the capillary vessels in a small animal, and it can be used with little trouble. Moreover, the fact
that it is insoluble in water renders it the more valuable, as injection can be carried on piecemeal as circum-
stances may require.

In dealing with the animals adopted for this tcok, a i-mall canula, provided with a tight-fitting india-
rubber ball or nipple, as figured below, is all-sufficient as a syringe.

For histological purposes, a gelatine injection is best suited, made as follows : — Allow a given quantity of
Nelson's gelatine to stand fcr twenty-four hours in twice its bulk of water, toil and stir well, adding either
French blue or vermilion to colour as required. This fluid should be injected at a temperature such as the
hand can comfortably bear.

In preparing a Frog for injection with gelatine, an incision should first be made along the whole ventral
integument (care being taken to injure nothing else), and the two halves reflected. Eaising the xiphoid process
with a pair of forceps, next insert the point of the scissors under this, and carefully remove the whole ventral
portion of the shoulder-girdle. By this means the heart will be exposed without injury, the pericardium
should now be laid open, and an incision made into the apex of the ventricle, to allow the escape of as much
blood as possible. When the animal is sufficiently well bled, a canula* should be tied into the heart, and
connected, by means of an inch or two of india-rubber tubing, with the syringe, injection being performed
under a gentle, steady pressure.

When the syringe is removed, the tube by which it was connected to the canula should be plugged with
a piece of glass rod, and the whole animal placed in water for two or three hours, that the injection may set.
After the above treatment, the parts to be preserved should be dealt with as recommended for the uninjected
tissues.

E. The term branch as applied to blood-vessels is often very vaguely employed. Defining an artery as a
vessel carrying blood from the heart, and a vein as one conveying it to the heart, it will be well to restrict
the term branch to those vessels formed by the breaking up of an artery into smaller trunks, and that of
factor to those uniting to form larger veins ; arteries and branches being efferent, factors and veins being
afferent, as related to the heart.

F. By a wet preparation is meant one that has never been allowed to dry.

The skeleton of the Frog may be readily prepared by allowing the body to lie in water for a few days,
after having first removed the skin, viscera, and as much of the flesh as possible. Maceration having
gone as far as is desirable, the whole should be put under running water for a day, before it is allowed to
dry.

* This m«st be made to the required size by drawing out a piece of glass tubing, either in a flame or by means of the blow-
lould be shghtly constricted near the apex, to allow of its being firmly tied into the heart.

APPENDIX. 109

The process of maceration may be materially hastened by using warm water instead of cold ; this method
should, however, be adopted with caution, as the parts rarely hold together so successfully as under the first-
named treatment.*

When careful preparation of both bony and cartilaginous parts is needed, as in the case of the skull figured
in this work, the only reliable method is that of dissecting away the soft parts under water, preserving the
whole in spirit as in the case of an ordinary dissection.

Gr. By far the most successful preservative fluids for histological work are alcohol and picric acid ; of the
latter, either a cold saturated solution or Kleinenberg's preparation will suffice for the purposes of this work.t

The tissue to be preserved should be removed from the body as soon as possible after death, cut up into
small pieces, and put at once into the preservative medium. For most tissues six to eight hours' immer-
sion will be found to suffice, after which the preparation must be transferred to alcohol of gradually increasing
strength, viz., 50 p.c., 75 p.c., methylated spirit, and absolute alcohol. Should any excess of acid be present, as
can readily be seen from the colour of the spirit, the latter must be repeatedly renewed until it is removed.
When this stage is reached the tissue is ready for cutting, and if preserved longer should be kept in
absolute alcohol.

Where the tissues are transferred at once from the body to alcohol, the method of treatment should also
be as above stated ; if osmic acid is used, the preparation should be transferred from it to 50 p.c. alcohol, as
soon as it begins to assume a black tint. The requisite length of exposure to osmic acid will be found to vary
for different tissues, and experience alone can enable the student to use this reagent with success. Where
decalcification is necessary, the tissue to be operated upon should be placed for twenty-four hours in ^ p.c.
solution of chromic acid, then for a similar time in 1 p.c. solution, this being either renewed or replaced by u
still stronger when necessary. Decalcification completed, the tissue must be transferred to alcohol as above.

For purposes of staining there is no reagent which gives such uniformly good results as Grenacher's
solution of borax carmine. The preparation may be allowed to remain in this for a couple of days, without
fear of overstaining. When stained, it should be again transferred to methylated spirit and absolute alcohol,
before imbedding, in order that any water or excess of staining fluid may be got rid of.

Imbedding.— The best imbedding material is paraffin, preferably that which shall melt at from 50'
to 60° C.

A block of this substance of the calibre of a candle, and about an inch and a half in length, will suffice
for all requirements here needed. A pit should be made at one end, large enough to take the prepara-
tion with ease. The preparation, previously soaked in turpentine to saturation, should be first transferred to
paraffin, the temperature of which must not exceed that of its melting-point, and allowed to remain in the
same until permeated thereby; it must next be finally transferred to the block prepared to receive it, and
completely covered in paraffin, the whole being then allowed to cool.

Section cutting. — For the purposes of this book an ordinary razor will suffice with which to cut sections ;
but where a successional series of slices are required, recourse must be had to one of the many microtomes now
in use.

Before cutting the sections, it is desirable to remove as much of the imbedding material as possible from
around the preparation.

When once mastered, the following is the least laborious of all methods of cutting and mounting.

0 The results of a long experience, in this and other matters which pertain to the preparateur's art, will be found embodied
in Wilder and Gage's "Anatomical Technology," New York and Chicago, 1882.

t The modo of preparation of these and other preservative and staining reagents, will be found fully stated in Huxley and
Martin and other similar works, and the student will find of great service a list of those reagents which have yielded such
admirable results in connection with the zoological station, Naples. See Jour. R. M. Sue., Series 2, vol. ii., 1882.

110 ATLAS OF BIOLOGY.

Transfer the sections as cut, together with the imbedding material in which they lie, to a slide, the
surface of which has been previously painted over with a heated solution of white shellac in kreasote.
Submit the whole to the temperature of the melting-point of the paraffin, until the kreasote is evaporated,
when the sections will become firmly adherent to the shellac. The slide must next be immersed in turpentine,
which will dissolve up the remaining imbedding material, thus leaving the sections fixed in place and ready
to be covered with Canada balsam.

For final mounting well-powdered Canada balsam, first thoroughly dried, must be dissolved in benzole or
chloroform, to the consistency of glycerine. A drop of the balsam thus prepared should be deposited upon the
slide by means of a glass rod, and allowed to diffuse itself among the sections ; the cover-slip should then be
let down gently and obliquely upon the objects, its under surface first having been smeared with Canada
balsam.

Under the above method of preparation the sections may be cut with a dry razor, but where, as in the
case of vegetable stems, etc., they are to be taken from material which has not been submitted to any such
treatment, both razor and preparation must be kept moistened during the process with the fluid in which the
preparation has been preserved.

Fresh preparations of animal tissues, when not frozen, must always be examined in serum or normal salt
solution. For the examination of fresh vegetable tissues, water will suffice.

The microscope used in making the drawings for this volume was one by Zeiss of Jena, and in the
formulae given in the text (example D. 2) the letter refers to the eye-piece, and the numeral to the objective
employed.

In no case should a high-power eye-piece be resorted to unless absolutely indispensable, as the sharpness
of definition obtained by low ones, such as Zeiss 2 or 3, is highly desirable.

A micrometer of some kind is indispensable to the student of histology, and the purpose to be aimed at
in its use, is that of a knowledge of the size of the objects under examination, rather than that of merely
ascertaining the magnifying power of the microscope. Most satisfactory results are to be obtained by using
an eye-piece micrometer ruled in squares, and by drawing both these and the object to the proportions
observed. Having thus a record of objects, drawn in proportion relative to squares of unknown value, it
remains but to ascertain the dimensions of these. This is best done by using, in conjunction with the
eye-piece micrometer mentioned above, a stage micrometer, ruled to known intervals, whereupon there will be
superposed lines of known and unknown value. The actual value of the squares of the eye-piece micrometer
may now be once for all calculated, and a record kept of the same for each lens combination.

H. Preparations of shells and similar hard parts are best made as follows : —

A small piece of the structure to be prepared should be first isolated, and then cemented with Canada
balsam to a piece of plate glass. When quite set it can be ground down on a rough surface to the required
thinness, and finally dislodged for mounting, by submerging the whole in benzole. It may then be put up in
Canada balsam in the usual manner.

I. For object-glass culture it is best to use either a small cell of the ordinary type, or a slide which is
excavated. Filling this with the nutritive fluid— water for protococcus, Pasteur's fluid for the moulds, sugar-
solution for the pollen-grain, etc.— next introduce the organisms upon which observation is to be made, and
place a cover-slip over the whole, the edges of which should be oiled to check evaporation. If the observation
be a prolonged one, it is well to place the nutritive medium in communication with a reserve of the same
fluid, by means of a cotton thread.

APPENDIX. Ill

J. The animals dealt with in this work are best killed as follows : —

The Frog. — Place the animal beneath an inverted tumbler, together with a piece of cotton-wool an inch
square, saturated with chloroform, and cover the whole with a cloth.

The Crayfish. — Easily killed under chloroform as above.

Crayfish may be kept alive and active for some days in a moist atmosphere, and fed upon sopped bread.
They thrive much better in captivity under this treatment, than any other known to me.

The Earthworm. — Earthworms may be killed, with the body naturally extended, by immersing them for
two minutes in methylated spirit, and then in running water for half-an-hour.

The Snail. — Snails can be killed with their tentacles often fully extended, by placing them in water as
hot as the hand will comfortably bear it.

The Mussel. — Place the animal in cold water, and heat slowly to 40° C. The foot will generally be well
protruded at death, under this treatment.

112

ATLAS OF BIOLOGY.

Ann. N. Hist.
Ann. Sci. Nat.
Arb. Wilrz.
Archv. Mk. Anat.
Archv. Mus. Paris.
Archv. Z. Kxp.
Her. (lies.
Bot. Zeit*
Opt. Rend.
Denk. Kais. Akad.
Enc. Brit.
Jour. Anat.
Jour. R. M. Soc.t
Mem. Akad. St. P.
Morph. Jahrb.
Phil. Trans.
Pr. R. Soc.
Pr. Z. Soc.
Q ,T. M. S.
Rev. Sci.
Stzb. Bonn.
Stzb. Wien.
Zeitsch. Jena.
Zeit. W. ZooL
Zool. Anz.*

BIBLIOGRAPHY.

LIST OF ABBREVIATIONS.

Annals and Magazine of Natural History.

Annales des Sciences Naturelles.

Arbeiten aus dem Zoologisch-Zootomischen Institut der Universitat.

Archiv fiir Mikroskopische Anatomie.

Nouvelles Archives. Museum d'Histoire Naturelle.

Archives de Zoologie Experimentale.

Berichte der Oberhessischen Gesellschaft fiir Natur-und Heilkunde.

Botanische Zeitung.

Comptes Bendus de 1'Academie Frangaise.

Denkschriften der Kaiserlichen Akademie der Wissenschaften.

Encyclopedia Britannica.

Journal of Anatomy and Physiology.

Journal of the Eoyal Microscopical Society.

M&noires de 1'Acadcmie Imperiale des Sciences.

Morphologisches Jahrbuch.

Philosophical Transactions of the Royal Society.

Proceedings of the Royal Society.

Proceedings of the Zoological Society.

Quarterly Journal of Microscopical Science.

Revue Scientifique.

Sitzungsberichte der Niederrheinischen Gesellschaft fiir Natur- und Heilkunde.

Sitzungsberichte der Kuiserlicheu Akademie der Wissenschaften.

Jenaische Zeitschrift fiir Medicin und Naturwissenschaft.

Zeitschrift fiir Wissenschaftliche Zoologie.

Zoologischer Anzeiger.

London.
Paris.
Wiirzburg.
Bonn.
Paris.
Paris.
Giessen.
Leipzig.
Paris.
Vienna.
9th Edition.

London and Cambridge.
London.
St. Petersburg.
Leipzig.
London.
London.
London.
London.
Paris.
Bonn.
Vienna.

Leipzig and Jena.
Leipzig.
Leipzig.

* A systematic record, giving the full titles of all monographs, etc., produced from time to time in its own branch of
natural science, will be found in this periodical.

t Brief translations and abstracts of certain of the more important biological papers published, exclusive of those on
gross vertebrate anatomy, are issued with this Journal.

FROG.

1. BLOOMFIELD, J. E. — On the Development of the

Spermatozoa in Helix and Rana. Q. J. M. S.,
vol. xxi., 1881.

2. BOAS, J. E. V. — TJeber den Conus Arteriosus, und

die Arterieubogen der Ampliibien. Morph. Jahrb.,

vol. vii., 1881.
8. BOUKNE, A. G. — On Certain Abnormalities in the

Common Frog. Q. J. M. S., vol. xxiv., 1884.
4. DE WATTEVILLE, A. — A Description of the Cerebral

and Spinal Nerves of Rana esculenta. Jour.

Awil vol. ix,, 1875,

5. ECKEH, A. — Icones Physiologicse. Leipzig, 1851-9.

6. ECKER, A. — Die Anatomie des Frosches. Part I.

Brunswick, 1864.

7. FUBBRINGER, M. — Zur Vergleichenden Anatomie und

Entwicklungsgeschichte der Excretionsorgane der
Vertebraten. Morjili. Jahrb., vol. iv. 1878.

8. G(ETTE, A. — Die Entwicklungsgeschichte der Uuke.

Leipziij, 1875.

9. HOFFMANN, C. K. — Bronn's Klassen und Ordnun-;eu

des Thierreichs. Vol. vii., Amphibien, Jsifiziij
und HeiJelbenj, 1873-8.

BIBLIOGRAPHY.

113

10. HOFFMANN, C. K. — Beitrtige zur Kenntniss des

Beckensder Anrphibienmd Reptilien. Leitlen,1876.

11. HUXLEY, T.H.— Article" Amphibia." Ktic. Brit., 9th

Edit.

12. JOUBDAIN, A. — Recherches sur le systeme lympha-

tique de la Rana tcmporaria. /.'•'. "»/'.. 1888.
See also papers by Langer, Stzb, Wien, 1866.
7, 8, and Ann. X. Hist., 1868.

18. KLEIN AND NOBLE SMITH. — Atlas of Histology,
London, 1879-80.

14. KNAUER, F. K. — Natnrgeschichte der Lurche.

Vienna, 1878.

15. LEYDIG, F. — Die Anuren Batrachier der Deutschen

Fauna, noun, 1877.

16. MARSHALL, A. M. — Certain Abnormal Conditions of

the Reproductive Organs in the Frog. Jour.
Anat., vol. xviii., 1884.

17. MULLEB, W. — Ueber Entwicklung and Bau der Hypo-

physis und des Processus infundibuli cerebri.
Zeitsch. Jena., vol. vi., 1871.

I?A. OSBOBNE, H. J. — Observations upon the Urodele
Amphibian Brain. Zool. Am., vol. vii., 1884.

18. PARKER, \V. K. — On the Structure and Development

of the Skull of the Common Frog. /'/<//. Trains.
1871.

19. RANVIER, L. — TechnischeB Lehrbuoh der Histologio,

Gentian Translatum. Lei/>ziy, 1877.

20. RAUBER, A. — Neue Grundlogungen /ur Konntniss der

Zelle. Morph. Jahrb., vol. viii., 1882.

21. SEDOWICK, A. — Early Development of the Wolffian

Duct., etc. Q. J. M. S., vol. xxi., 1881.

22. SPENOEL, J. W. — Das Urogenitalsystem der Amphi-

bien. Arl>. Wiirz., vol. iii., 1876.

28. WHITNEY, W. N. — The Changes which accompany
the Metamorphoses of the Tadpole, etc. Q. J. M. S.,
vol. vii., 1867.

24. WlEDERSHEIM UND EfKKB. Die Anatomic lies

Frosches. Parts ii. and iii. ttniitmcick, 1U81-2.

CRAYFISH.

25. ALBERT F. V. — Das Kaugeriist der Dekapoden.

Zeit. W. Zool, vol. xxxix., 1888.

26. GERSTAECKER, A. — Bronn's Klassen und Ordnungen

des Thierreichs. Vol. v., Arthropoda. Ldiizuj,
1866 to date.

27. HERRMANN, G. — Spermatogonesis de Crustacea Podo-

phthalmiques. L'jit. Rend., 1881.

28. HUXLEY, T. H. — On the Classification and Distribu-

tion of the Crayfishes. I'r. /*. Soc., 1878.

29. HUXLEY, T. H.— The Crayfish, etc. International

Scientific Series, 1880.

80. JOURDAIN, S. — Sur les cylindres sensoriels de

1'autenne interne des Crustaccs. Opt. Eetul., 1880.

81. MOCQUARD, M. F. — Recherches anatomiqucs sur

1'estomac des Crustacea podophthalmaires. Aim.
Sci. Nat. Zool, 1888.

82. RATHKE, H. — Ueber die Bildung und Entwicklung

des Flusskrebses. Leipzig, 1829.

I 88. REICHENBACH, H. — Die Embryuiinnlago und ersto
Entwicklung des Flusskrebses. Zrit. W. Zool.
1877. Abstract by T. J. Pa, her, Q. J. M. S.
vol. xviii., 1878.

84. RUTHERFORD.— On the Structure of Arthropod Muscle

I'r. R. Soc. Kilinbunjh, 1888.

85. SABS, G. 0. — Om Huminerens postembryonale

udvikling. ( hrisliuna, 1874.

See also a paper by S. J. Smith, in Train. Con-
necticut Aead. nj Artx and Scifiicm, vol. ii., 1878.

86. WASSILIEW, E. — Ueber die Niero des Flusskrebses.

Zool. Anz., vol. i., 1878.

87. WEBEB MAX.— Ueber den Bau und die Thutigkei1

der sogenannten Lebcr der Crustacean. Arehc.
Mk. Anat., vol. xvii., 1880.

87«. WOODWARD, H. — Article " Crustacea," Km: Brit.,
9th Edit.

EARTHWORM.

88. BEDDARD, F. E. — On the Anatomy and Histology of

Pleurochaeta Moseleyi. Trans. Royal Soc. Edin.
burgh, 1882.

89. BEDDARD, F. E. — Note on Some Earthworms from

India. Ann. N. Hist., 1888.

40. BEDDARD, F. E. — On the Anatomy of a Gigantic
Earthworm, etc. Pr. Z. Soc., 1884.

41. BLOOMFIELD, J. E. — On the Development of the

Spermatozoa of Lumbricns. Q. J. M. S., vol. xx.,

1880.

42. CLAPABEDE, E.— Histologische Untersuchungen iiber

den Regenwurm. Zcit. W. Zool., vol. xix., 1869.
48. DABWIN, C.— The Formation of Vegetable Mould
through the Action of Worms, etc. 1881.

15

114

ATLAS OF BIOLOGY.

44. GKOKNBAUK, C. — Ueber die sogcnanntcn Respira-

tionsorgane des Regenwurms. Zeit. W. Zool.,
vol. iv., 1853.

45. BERING, E. — Zur Anatomic und Physiologie der

Generationsorgane des Regenwurms. Zeit. W-
Zool., vol. viii., 1857.

40. KLEINENBERG, N. — The Development of Lumbricus
trapezoides. Q. J. M. 8., vol. xix., 1879.

47. KOWALEVSKY, A. — Embryologische Studien an Wiir-

mern und Artbropoden. Mem. Akad. St. P.,
vol. xvi., 1871.

48. LANKESTER, E. 11. — The Anatomy of the Earthworm.

Q. J. M. S., vol. iv. and v., 1864-5.

49. LANKESTER, E. R. — The Red Vascular Fluid of the

Earthworm a Corpusculated Fluid. (J. J. J/. S.,
vol. xviii., 1878.

50. MOJSISOVICS, A. v. — Die Lumbrieiden Hypodcrmis

Stzb. Wieii, vol. Ixxyi., 1877.

51. PERRIER, E. — Etudes sur 1'organisation des Lotn-

briciens terrestres. Archc. '/i. Ex//., vol. ix.

52. PERRIEE, E. — Memoirs pour servir a 1'histoire des

Lombriciens terrestres. Arc/iv. Mas. Paris,
1872.

53. POWER, D. — On the Endothelium of the Body Cavity

and Blood Vessels of the Common Earthworm,
etc. Q. J. M. S., vol. xviii., 1878.

54. ROBINET, CH. — Recherches Pbysiologiques sur la

Secretion des glandes de Morren du Lumbricus
terrestris. Cpt. Reitd., vol. xcvii. 1888.

55. ROLLESTON, G. — The Blood-corpuscles of the Anne-

lids. Jour. Anat., vol. xii., 1878.

SNAIL AND MUSSEL.

56. BAHFURTH, D. — Ueber den Bau und die Thiitigkeit

der Gasteropoden Leber. Archc. 21k. Anat.,

voL xxii., 1888.

See also Preliminary Note, Zool. Anz., 1880.

57. BAUDELOT, M. E. — Sur 1'Appareil Generatenr des

Mollusques Gasteropodes. Paris, 1863.

58. BLOOMFIELD, J. E. — See No. 1 this list.

59. BOHHING, L. — Beitrilge zur Kenntniss des Central-

nervensystems einiger Pulmonaten Gasteropoden.
Leipzig, 1888.

60. BRAUN, M. — Postembryonale Entwickelung der Siiss-

wasser-Muscheln. Zooloyisclier Garten.

61. BKONN AND KEFERSTEIN. — Klassen und Ordnungen

des Thierreichs. Vol. iii. Malacozoa. Leipzig,
1862-6.

62. CAHRIERE, J. — Die Embryonale Byssusdriise von

Anodonta. Zool. Anz., 1884.

63. CATTIE, J. — Ueber die Wasseraufnahme der Lamelli-

branchiaten. Zool. An:., 1883.

64. FLEMMING, J. — Ueber die Blutzellen der Acephaleu

und Bermerkungen ueber deren Blutbahn.

Also — Bemerkui.g zur Injectionstechnik bei Wir-

belloeen. Archc. Mk. Anat., vol. xv., 1878.

65. GRIESBACH, H.— Wasseraufnahine bei den Mollusken.

Zool. Anz., 1884.

66. JHERING, H. von. — Ueber die Entwickelung von

Helix. Zeitsch. Jena., vol. ix., 1875.

67. JHERING, H. YON.— Znr Kenntniss der Eibildung tei

den Muscheln. Zeit. W. Zool., vol. xxix., 1877.

68. JHERING, H. VON. — Zur Morphologic der Niere der

sogenannten Mollusken. Zeit. W. Zool., vol. xxix.,
1877.

69. JOURDAIN, S. — Sur la conformation de 1'Appareil de

la Generation de 1'Helix aspersa dans le jeune
Age. Rev. Sci., 1880.

70. KEBER, G. A. — Beitrilge zur Anatomie und Physiolo-

gie der Weichthiere. Konii/sberg, 1851.

71. LANGER, K. — Das Gefiiss- System der Teichmuschel.
Denk. Kais. Akad., 1855-6.

72. LANKESTER, E. R. — On the Development of the Pond

Snail. Q. J. M. S., vol. xiv., 1874.

73. LANKESTER, E. R. — Article " Mollusca," Ene. Brit.,

9th Edition.

74. LANKESTEH, E. R. — The Supposed Taking-in and

Shedding-out of Water, in Relation to the Vascu-
lar System of Molluscs. Zool. Anz., 1884.

75. MITSUKURI, K. — On the Structure and Significance of

some Aberrant Forms of Lamellibranchiate Gills.
Q. J. M. S., vol. xxi., 1881.

76. NUSSLIN, 0. — Beitrilge zur Anatornie und Physiologie

der Pulmonaten. Tubingen, 1879.

77. PECK, R. H. — The Minute Structure of the Gills of Lamel-

libranchiate Mollusca. Q.J.M.S., vol. xvii., 1877.

78. PENROSE, F. G. --Note on the Vascular System of

Lamellibranchs.

Report of the Committee on the Zool. Station,

Naples. British Association Reports, 1882.

79. RiicKER, A. — Uber die Bildung der Radula bei Helix

potnatia. Ber. Gies., 1883.

80. SOCHACZEWER, D. VON. — Das Riechorgan der Land-

pulmonaten. Zeit. W. Zool., vol. xxxv., 1880.

81. SPENGEI., J. W. Die Geruchsorgane und das

Nervensystem der Mollusken. Zeit. W. Zool.,
vol. xxxv., 1B81.

BIBLIOGRAPHY.

HYDUA.

115

82. ALLMANN, G. J. — On the Gymnoblastic Hydroids.

Rtty.Soeittg'i PabUfatiotu, 1871.
88. BRASS, A. — Untersuchungen der Histologie von Hydra

viridis. Zeitschrift fur die yesamint. Xaturicisx.

vol. liii., 1880.

84. ENGELMANN, T. W. — Ueber Trembley's Umkebrungs-

versuch an Hydra. Zool. Am., vol. i.,
1878.

85. HAACKE, W. — Zur Speciesunterscheidung in der

Gattung Hydra. Zool. Am., vol. ii., 1879.

86. HAMANN, 0.— Zur Entstehung und Entwicklung der

griinen Zellen bei Hydra. Zelt. W. Zool.,
vol. xxxvii., 1882.

87. HARTOG, M. M. — On the Means by which Hydra

swallows its Prey. /'roc. Maneheittr Literary and
Philosophic Society, vol. xix., 1881.

88. HICKSON, 8. J. — Abnormal Appearances of Hydra

viridis. Jour. />'. M. Soc., vol. i., 1878.

89. JICKELI, C. F.— Ueber Hydra. Zool. Am., vol. v.,

1882.

90. JUNG, H. — Beobachtuugen iiber die Eutwicklung cles

Tontakul Krauzes von Hydra. Morfih. Joln-b.,
vol. viii., 1882.

<J1. KLEINENBERO, N.— Hydra. Eine Anatomisch Ent-
wickeluugsgeschichtL Untersuchung. Leipzig, 1872-
Abstract by Allmann in (,'. ./. M. ,S'., vol. xiv., 1874.

92. KOBOTNEFK, A. VON. — Zur Kenatuiss der Embryologio
von Hydra. Zeit. W. Zool., vol. xxxviii., 1888.

98. LANKESTEB, E. R.— Article "Hydrozoa," Enc. Brit.,
9th Edit.

94. LANKESTEB, E. R. — On the Chlorophyll-corpuscles

and Amyloid Deposits of Spongilla and Hydra.
Q. J. M. S., vol. xxii., 1882.

See also a postscript to a paper by fr'. (I. Jiotrer,
On the Origin and Morphology of Chlorophyll
Corpuscles. Q. J. M. S., vol. xxiv., 1884.

95. LANKESTEB, E. R. — On the Intra-cellular Digestion

and Endoderm Cells of Lymnocodinm. Q. J. M. S.,
vol. xxi., 1881.

96. MARSHALL, W. — Ueber eiuige Lebenserschuinungen

der Siisswasserpolypen und iiber eine neue Form
von Hydra viridis. Zeit. \V. Zwl., vol. xxxvii.,
1882.

97. PABKER, T. J. On the Histology of Hydra fuson.

Pr. It. Sm\, 1880. Also Q. J. M. S., vol. xx.,
1880.

UNICELLULAR ORGANISMS.

98. AUERBACH, L.— Ueber die Einzelligkeit der Amaben. 106.

Ztit. W. Zool., vol. vii., 1856.

99. BREFELD, 0.- Botanische Untersuchungen iiber 107.

Schimmelpilze. Part iv., Leipzig, 1881.

100. BUTSCHLI, 0. — Bronn's Klassen und Ordnungen des 108.

Thierreichs. Vol. i., Protozoa, Leipzig, 1880-4.

101. COHN. — Untersuchungen iiber Bacterien. Beitriige

zur Bioloyie tier Pflanzen. Brestau. Heft 2, 109.

1872. Hefk 8, 1875. Band 2, Heft 2, 1876.

See also Q. J. M. S., vol. xiii., 1878; vol. xvi., 110.
and vol. xvii., 1876-7.

102. DALLINGER, W. H.— On the Measurement of the 111.

Diameter of the Flagella of Bacterium termo, etc.
Jour. R. M. Soc., vol. i., 1878. j 112.

108. ENGELMANN, T. W.— Znr Physiologic der Contractilen

Vacuolen der Infusionsthiere. Zool. An:., vol. i., 118.

1878.

See also a .Vote in the same — Ueber Gasentwick- 114.

lung im Protoplasma lebender Protozoen.

104. EWART, J. C. — On the Life-History of Bacillus 115.

anthracis. (J. J. M. .S'., vol. xviii., 1878.

105. EWART, J. C. — On the Life-History of Bacterium 110.

tcrmo and Micrococcus. Pr. 11. Soc., 1878.

GEDDES AND EWART. — On the Life-History

Spirillum. Pr. II Soc., 1878.
GRUBER, A. — Beitriige zur Kenntniss der Amoben.

Zeit. W. Zool., vol. xxxvi., 1882.
GRUBER, A. — Ueber Kerntheilungsvorgiinge bei

einigen Protozoen. Zeit. W. Zool., vol. xxxviii.,

1888.
GRUBER, A. — Ueber Kern und Kernthuiliing bei don

Protozoen. Zeit. \V. Zool., vol. xl., 1884.
GRUBER, A. — Studien iiber Amoben. Zeit. W.

Zool., vol. xli., 1884.
HUXLEY, T. H. — Article on " Yeast," CotUemi>orary

lievieir, 1871.
JICKELI, C. F. — Ueber die Kernverhtiltnisse der

Infusorien. Zool. Am., vol. vii., 1884.
KENT, W. S. — A Manual of the Infusoria. Lotiilon,

1880-81.
KLEBS, G. — Beitruge zur Kenntniss niederer Algon-

formen. Bot. Zeit., 1881.
KLEIN, E.— Koch's New Method of Pure Cultivation

of Bacteria. Q. J. M. S., vol. xxi., 1881.
LANKESTER, E. R. — On Bacterium rubescens, etc.

Q. J. M. i'., vol. xvi., 1876.

116

ATLAS OB^ BIOLOGY.

117. LANKESTER, E. R. — On Lithamoeba discus. Q. Jf

M. S., vol. xix., 1879.

118. LEIDY, J. — Freshwater Rhizopods of North America.

Publications of the United States Geographical
Survey, Washington, 1879.

119. NAGELI.C.VON. — TheoriederGarung. Miinchen,l87Q.

120. REES MAX. — Eotanische Untersuchungen iiber die

Alkoholgahrungspilze. Leipzig, 1870.
See also A. W. Bennett. Some Account of Modern
Researches into the Nature of Yeast. Q. J. M. S.,
vol. xv., 1875.

121. RYDER, J. A. — On the Chlorophyll Granules in

Vorticella.

Proc. United States National Museum, vol. vii.,1884.

122. SALLITT, JESSIE. — On the Chlorophyll Corpuscles

of some Infusoria. Q. J. M. S., vol. xxiv., 1884.

122A. SCHUTZENBERGER, P. — On Fermentation. Intermit.
Scientific Series. 187G.

123. TYNDALL, J. — The Optical Deportment of the

Atmosphere, in Relation to the Phenomena
of Putrefaction and Infection. Phil. Trans., 187(i.

124. TYNDALL, J. — Further Researches on the Deport-

ment and Vital Persistence of Putrefactive and
Infective Organisms from a Physical Point of
View. Phil. Trans., 1877. See also the same
author's " Floating Matter of the Air, etc." Lon-
don, 1881.

125. WALLICH, G. C. — On the Value of the Distinctive

Characters of Amoeba. Ann. N. Hist., 1863.
See also other papers in the above, by the same
author.

FUNGI.

126. DE BARY, A., AND WOHONIN. — Beitrage zur Mor-

phologie und Physiologie der Pilze. Vol. i.,
Frankfort, 1864-70.

127. DE BARY, A. — Vergleichende Morphologie und

Biologie der Pilze, etc. Leipzig, 1884.

128. BREFELD, 0. — Botanische Untersuchungen der

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