Handle with EXTREME CARE This volume is damaged or brittle and CANNOTbe repaired! photocopy only if necessary return to staff do not put in bookdrop Gerstein Science Information Centre /T/ / \ BIOLOGICAL ATLAS A GUIDE TO THE PRACTICAL STUDY OF PLANTS AND ANIMALS to flje requirements of tije iLonUon ^Eni&ersttjj, Science an& art department, an& for use in Schools anto Colleges WITH ACCOMPANYING TEXT CONTAINING ARRANGEMENT AND EXPLANATION, EQUIVALENT TERMS, GLOSSARY AND CLASSIFICATION 423 COLOURED FIGURES AND DIAGRAMS D. M'ALPINE, F.C.S. LECTURER ON BIOLOGY AND BOTANY, EDINBURGH, AND HONOURMAN OF THE SCIENCE AND ART DEPARTMENT; AUTHOR OF "SHORT NOTES FOR BIOLOGICAL STUDENTS," AND "A ZOOLOGICAL ATLAS " AND A. K M'ALPINE, B.Sc. (Honours) LOND. LECTURER OS BOTANY, SCHOOL OF MEDICINE, EDINBURGH ; PROFESSOR OF BOTANY AND NATURAL HISTORY, NEW VBTERINAR7 COLLEGE, EDINBURGH, AND ASSOCIATE OF THE ROYAL COLLEGE OF SCIENCE FOR IRELAND FIFTH THOUSAND W. & A. K. JOHNSTON EDINBURGH AND LONDON JIDCCCLXXXI PREFACE. IT is now generally recognised that a certain acquaintance with actual specimens is necessary for the proper understanding of Plants and Animals. By the practical study of representative forms, exemplifying the leading modifications of plant and animal life, the student obtains a basis of distinctly observed fact with which to compare other forms, and round which to cluster the infor- mation derived from books. The University of London has given practical shape to this idea by selecting a series of common types which " each candidate must be prepared to examine microscopically, to dissect and to describe." In this Atlas, which is intended to serve as a guide to, and not as a substitute for, practical work, drawings are given of the various points of importance exemplified by each of these types, to enable the student to make out the points for himself on the actual specimens. Experience both as students and teachers has taught us, that in this constant appeal to the object itself, the student is greatly assisted by clear and accurate drawings. In the triple alliance, as it may be called, of description, drawing, and object, is found the easiest, safest, and surest means of successful study. Not only is the Atlas a guide to practical work, but since it contains the results of that work in a permanent form, a glance at the drawings with their accompanying description will serve as a valuable refresher to the memory before going up for examination. Further, the Atlas may be used with any of the Text-books of Zoology or Botany in common use, such as those of Huxley, Nicholson, Macalister, Sachs, M'Nab, etc., because equivalent terms are noted in the text, and thus the language of the science is translated as it were into the different dialects. The drawings belonging to each form represent the leading features in the history of its life. The structure as a whole is first shown, then the details of the various parts by means of separate drawings, and finally so rmich of the history of its development as is likely to be required. In every case the types represented have been practically examined, and drawings made from nature. A number of the drawings are taken from dissections and microscopic preparations made in the Biological Laboratory of the Eoyal School of Mines, London. Others are copied from reliable sources whenever they give clearly and correctly the most instructive view of the object. In the development special care has been taken to give only such representations as were drawn by practised observers, e.g. the development of the Amoeba is taken from Haeckel, and that of the Cray- fish from Eathke. Drawings after nature are headed Figures, and Diagrams are occasionally introduced for explanatory purposes. The explanatory text arranges the information obtained from the drawing in a convenient form, explains briefly the nature of the object seen, states equivalent terms when the same thing is differently named by standard authors, gives the derivation of names when that throws light on their meaning, and accents them where there is any danger of wrong pronunciation, and finally sums up the distinctive cJiaracters in the form of a classification. iv PREFACE. A few general practical directions are given to enable the student to adopt those expedients in the examination of specimens which experience has shown to be the best. These instructions are necessarily brief, but a detailed account is less necessary since the methods to be pursued are given clearly and at length in Huxley and Martin's Elementary Biology, to which the student is referred. The following features of the Atlas may be specially mentioned : — The names of the various parts are placed on the drawing. The description faces the Plate. Colour is used to distinguish the different organs, and as a rule, corresponding parts have the same colour throughout in order to render comparison easy. The size of a microscopic object is generally given, or shown by means of squares, to prevent misconception. The comparative Histology of Frog and Man shows that a close correspondence exists between the structure of the Frog and that of higher animals, and thus justifies its detailed study as a representative form. The complete life-history is usually given. Separate drawings are freely used for the different systems of the Plant or Animal body, and thus all the evils and confusion arising from overcrowding are prevented. Equivalent terms allow of its being used with any standard text-book. No apology is needed for issuing a work of this kind. While there are large and well-executed wall-diagrams which the student may admire at a distance, there is no set of drawings at a convenient price and in. a handy form which lie can use as a map to show him the various regions of the Plant or Animal, and guide him in his attempts to explore them. It is hoped that the cheap and con- venient form of the Atlas may favour its introduction even into higher-class schools. There the study of Biology might be made a powerful instrument, both of information and training, and a valuable preliminary to the study of Physiology. We are much indebted to Mr. S. P. Eastick for valuable aid received while the work was in progress. No pains have been spared to ensure accuracy, yet doubtless some mistakes have escaped notice. EDINBURGH, January 1880. PREFACE TO THE SECOND EDITION. THE attempt to encourage practical work in Biology by means of clear figures briefly explained, and accompanied by instructions for the examination of specimens, has evidently been received with favour, since a second edition of the " Biological Atlas " has been called for within a year of publication. Both Text and Plates have been carefully revised, and such alterations and improvements made as will tend to render it still more serviceable. However, few changes have been found necessary. The colouring of the Animal portion of the work has been somewhat altered, in order to bring it into harmony with that of the " Zoological Atlas," to which the present work may be regarded as an introduction. D. M'A. EDINBURGH, April 1881. LIST OF PLATES, PLATE I. YEAST AND BACTERIA PLANTS INVERTEBRATE ANIMALS VERTEBRATE ANIMALS , II. BROWN MOULD AND GREEN MOULD ...... III. PROTOCOCCUS AND CHARA IV. CHARA (completed) AND BRACKEN FERN V. BRACKEN FERN (completed) .... VI. FLOWERING PLANT VII. „ ,, (continued) ...... VIII. ,, „ HISTOLOGY ...... IX. PROTEUS ANIMALCULE AND BELL ANIMALCULE . . . . X. FRESH-WATER POLYPE AND EARTH-WORM . XI. EARTH-WORM (completed) ....... XII. LoIiSTER AND CRAYFISH ....... XIII. „ „ (continued) ...... XIV. „ „ (continued) ...... XV. „ ., (completed) ...... XVI. FRESH-WATER MUSSEL ..... XVII. SNAIL XVIII. FROG — EXTERNAL CHARACTERS AND GENERAL ARRANGEMENT OP INTERNAL ORGANS ........ XIX. „ SKELETON ........ XX. „ CIRCULATION AND RESPIRATION . XXI. ,, NERVOUS AND MUSCULAR SYSTEMS . XXII. ,, SENSE-ORGANS, RENAL AND REPRODUCTIVE ORGANS, AND TADPOLE XXIII. ., DEVELOPMENT AND COMPARATIVE HISTOLOGY V XXIV. „ COMPARATIVE HISTOLOGY OP FROG AND MAN Facing page I 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 45 47 49 GENERAL DIRECTIONS FOR PRACTICAL WORK. FOB the examination and dissection of the various specimens the following apparatus will be required : — Dissecting Instruments. — Sharp knife or scalpel; forceps; dissecting needles; scissors; and dissecting dish. Dissecting needles may be readily made by fastening ordinary needles in penholdera To fasten the needle, hold it in a pair of pliers and push the sharp end into the wood ; withdraw the needle again and insert the blunt end. These needles may be made to cut by grinding edges on them. The needle is readily bent by heating in a gas flame and bending with the pliers. Such needles are very useful in dissecting flowers. Dissecting Dish. — A shallow vessel may be used, with a plate of wax, gutta-percha, or black paraffin (prepared by melting down solid paraffin and lampblack) covering the bottom, on which to cut up or pin down the specimen. A tight-fitting lid with a layer of cork fastened to the inside can be used as a dissecting board. Optical Instruments. — Microscope ; pocket lens, which may be used also as a dissecting microscope by having a fixed rod on which it can be moved up or down, leaving the hands free for teasing, etc. ; watch- maker's magnifying-glass, which may be used in dissecting out nerves, blood-vessels, or any minute structures. Small apertures are best made out by taking a glass tube drawn out to a fine point and blowing through it to enlarge the opening. Bristles can then be readily inserted. Reagents, etc. — Distilled water ; weak spirit ; solutions of magenta, carmine, iodine, salt, potash, and chromic acid ; glycerine ; acetic acid. A weak solution of bichromate of potash may bo used instead of spirit for preserving. A good plan for dropping reagents is to fix glass rods in the corks of the bottles. YEAST. Mounting. — Get some Yeast at the brewer's or the baker's, and place a small drop on a glass slide. Cover with a cover-glass for examination under a high power of the microscope. Staining. — Place a little of the staining solution beside the cover-glass, and arrange a slip of blotting- paper at the opposite side, so as to cause a current of the staining material. Crushing. — By gentle pressure of the finger or some blunt instrument the wall will burst and the contents flow out. To prevent breaking and dimming of the cover-class it is protected by a tiny pad of blotting-paper. BACTERIA. Mince some lean meat and soak in cold water for an hour ; filter, and keep in a warm place for several days ; examine the liquid and the scum which forms on the surface with the highest power of the microscope. MOULDS. Teasing. — Take a very small portion of the mould and lay it on a slide with a little water, then tease out by means of two dissecting needles. PROTOCOCCUS. Mounting. — Take a bit of the bark of any tree with green scum upon it, brush off the Protococci and mount in water. Mount a drop of water from a water-butt containing Protococci, stain with iodine, which kills the Protococci and renders the cilia visible. OHARA. Hardening. — A weak solution of chromic acid is used. The chromic acid, in addition to its hardening action, acts also as a solvent, dissolving any limy incrustation. Embedding the slender Stem. — Soak a piece with gum, which will fill up any cavities ; then harden the gum by dipping in alcohol, which removes water, leaving the stem surrounded by a coat of hardened gum. Place a vru little bit thus prepared in a hole scooped out in solid paraffin. Melt a little paraffin in a small spoon and pour around the specimen. Section-cutting. — Wet razor with alcohol by means of a brush. Cut a number of slices and transfer them with the brush to a watch-glass. Add water, the gum dissolves, and the sections become detached from the paraffin. PERN. Sections. — The rhizome cuts better after steeping for some time. Staining. — A transverse section of fibre-vascular bundle, for instance, consisting of hard and close-set cells, may be stained by soaking with magenta for some time in a watch-glass, then washing with water from a pipette before mounting. FLOWERING PLANT. Leaf. — Cut a small piece ont of blade of leaf. Dip it into gum and then into alcohol. Imbed in paraffin and cut transverse sections. Peel off a small bit of epidermis from the lower surface, say, of a geranium leaf, and examine in water. Anther. — Take anther from a flower before it opens. Dip in gum and alcohol before imbedding and cutting sections. Ovule. — One of the Speedwells may be used, e.g. Buxbaum's Speedwell. Dissect out ovules from ovary of flower from which corolla has just fallen, then tease them asunder under dissecting microscope in a drop of potash solution and add a little glycerine when mounting. Embryo. — The common Shepherd's Purse may be used. Dissect out the mature ovules or seeds from fruit. Commence with youngest fruit nearest the top, afterwards going to older, to get different stages. Mount in potash solution, press gently with cover-glass, and the embryo will be forced out through the micropyle. Seeds. — Beans or Peas are readily examined after steeping for a night in water. Germination. — Wheat and Indian Corn can be readily germinated by placing in moist tow, surrounded by flannel, and kept in a warm place. The root hairs and root cap can be readily seen on these young roots. AMCEBA. Examination. — The readiest place to find some form or other of Amoeba is in the slimy matter taken from decaying leaves in stagnant water. Mount in a drop of water and examine like Yeast. COLOURLESS BLOOD-CORPUSCLES. Examination. — Lay a drop of your own blood on a slide, then cover quickly with cover-glass. By means of a camel-hair brush surround with oil to prevent evaporation. VORTICELLA. Examination. — On minute Water-plants, such as Duck-weed, groups are usually found. The operation of feeding may be observed by introducing particles of indigo or carmine into the water. HYDRA. Examination. — Found in stagnant pools and ditches. To examine alive, mount in plenty of water under a large cover-glass. Sections. — Kill by adding boiling water. Harden, prepare, and imbed as in Chara. Sea-anemones treated in the same way might be used instead. EARTH-WORM. Dissection. — Kill with vapour of chloroform by placing in a stoppered bottle, with a few drops of chloro form. It then becomes stretched, and may be dissected under spirit. Fasten out in a dissecting dish, and with a fine pair of scissors slit it up longitudinally a little to one side of the middle line and pin out the two flaps. Needles with borax leads for heads are best for pinning out. IX FRESH-WATER MUSSEL. Dissection. — Cut through adductor muscles of one side and remove the valve. Note the beating of the heart. Kill with hot water. Harden in spirit before following the course of the alimentary canaL LOBSTER OR CRAYFISH. Dissection. — Eemove lateral portion of carapace by passing a knife under its free edge from the posterior end to cervical suture. This part of the carapace is the gill-cover or branchio'stegite (Gr. steyo, I cover). Notice scaphognathite working. Turn out the gills with the knife. Dissect from the left side, as in PL XIII. figs. 2 and 3. Place another specimen under water in dissecting dish and it soon dies. Remove dorsal portion of carapace and of abdominal somites with scissors, in order to make out the chief organs, as in PI. XIII. fig. 1. Preparation of Skeleton. — Boil in strong potash solution, which dissolves everything but the chitin or horny substance composing the shell The parts of the exoskeletou may be disarticulated and laid out in their natural order. SNAIL. The Edible Snail is the largest of all the Snails, hence its convenience for study ; but the Common Snail may be taken. Snails can be kept alive for a considerable time, and warm water generally makes them protrude from their shell. Boiling water kills them. Dissection. — Remove shell bit by bit with strong forceps, and pin the animal out in spirit, dissecting from the dorsal surface. Lay open pulmonary chamber, then expose the viscera by laying open the dorsal integu- ment of foot along middle line and removing the mantle. The viscera may next be laid out to display them to advantage. FROG. The Edible Frog is chosen on account of its larger size, but the Common Frog will also show the various points. Kill with chloroform. Dissection. — A dissection from the ventral surface may be made under water in the dissecting dish by cutting through the skin in the middle line from the symphysis of lower jaw to symphysis of pubis ; then pin out the skin on both sides, and various muscles, veins, etc., are brought into view. Next open abdomen a little to one side of anterior abdominal vein, cut through shoulder-girdle, and remove its central portion. The various viscera are then seen as in PI. XVIII. fig. 2. Turn over viscera to right side, cut away parts mentioned in PI. XVIII. fig. 3 (text), and pin out with left side upwards so as to get the sectional view. Prepare a specimen in spirit and nitric acid for the dissection of the nervous system. Dissect from dorsal surface, and remove the dorsal wall of the cerebro-spinal cavity by nipping it away with scissors, beginning at the junction of the skull and spinal column. Dissect out cranial nerves and the nerves of the limbs for a short distance. Remove brain and spinal cord and preserve in spirit for future use. Take a similarly prepared specimen and dissect from ventral surface. Remove the bodies of the vertebrae and the floor of the skull. Along each side of the spinal column dissect out the sympathetic system, and trace its connection with the cranial and spinal nerves as in PL XX. diag. 1. The principal cranial nerves may be dissected from the left side, as in PL XXI. fig. 5, after distending the gullet with a piece of glass tubing. Place in chromic acid, with a little nitric acid to hasten the softening of the bone and the hardening of the nerves. Section of Spinal OorJ. — Take a piece hardened in spirit, prepare and imbed in paraffin aa before, and mount transverse sections in glycerine. Circulation in Web. — In a thin piece of wood or cork make a notch to fit the web between two of the toes. Stretch the web over the notch by thread attached to the ends of the two toes. Keep the skin moist with wet blotting-paper, and after placing a small drop of water on the web, cover with triangular cover-glass for exam- ination under high power. Preparation of Skeleton. — After cleaning the bones roughly, steep for about a week in sufficient water to cover them, then place them for a few days in fresh water, which should be frequently renewed. They may be cleaned with a brush and then laid out in the sun to bleach. Any grease may be extracted from the bones by benzol YEAST PLANT (SACCHAROMYCES CEREVISI/E). PLATE I. WalV. Fig.2 Ytost Cell, with, Stul Fig. 3. Cell -with* Old' StLciiSy Yff Cfany of Cdlf Fig. 5. Formation; of ^scafpcm$ Fig. 8. •Sid*/ • •Sixes of 7ra*t - £200 Air (o. I*/ Di a£ram I. o PHYSIOLOGY OF YEAST Low Tanprraliire> Wal*r IO.S-1 Sugar /C. O. S.j -Jrnrrumiu/n Tartra totassmm Phosphate* IK P. O. ) Calcium Phosphate, (Ca,.P. O / Julpfhale- fMg.S.O. y Carbonic* 1C. O.I •Oft -Scy, o o O O O OO oo o oo o o o QQOO O O OO Wattr Alcohol fC. 0.3:1 CApxrint, I C. O. B./ SwxiiurAcuL 1C. O.S./ BACTERIA Fig. I. r\ r\ Qyyge r\ Water- with; T*r3t* fc Merc&ry Treated, with, Potash- added- Fi 6 . I C H A R A Fi4. 3 Trtmsvers* Stctum of Nodi,' iming .L oytr of chbjrophyH qranales PLATE IIL PROTOCOCCUS. PROTOCOCCUS VULGAEIS, the green scum on the bark of trees (Gr. protos, first ; kokkos, a berry). Fid. 1. Showing — f Cell-wall or sac. A CELL -c Protoplasm containing green, sometimes red, chlorophyll (Gr. chloros, green ; phyllun, a ( leaf). FIG. 2. EFFECT OF — «. Iodine — Protoplasm stained and nucleus brought out. b. Iodine and sulphuric acid — The cell-wall becomes blue and the protoplasm coagulates. The sulphuric acid converts cellulose into starch, and the iodine with starch forms the blue iodide of starch. e. Crushing causes rupture, and shows that the cell-wall is tough and resisting, while the proto- plasmic contents are semi-fluid. d. Potash (KHO) dissolves out the protoplasmic contents. FJG. 3. Showing MULTIPLICATION BY DIVISION — a. Division into two. b. Division into four. This process is the same as that which goes on at the growing point in the higher plants (See Chara, fig. 4.) FIG. 4. Showing MULTIPLICATION BY ENDOGENOUS DIVISION AND PRODUCTION OF MOTILE FORMS— a. The protoplasm has gathered itself up into a number of round masses, each of which is a zoospore or zoogonidium (Gr. zoos, alive ; gune, seed). b. A zoospore that has escaped from the parent cell. It consists of a naked mass of protoplasm, with two long vibratile protoplasmic threads or cilia by which it moves about. PROTOCOCCUS PLUVIALIS, found in water-butts (L. pluvia, rain). ( Cell-wall. FIG. 1. RESTING FORM < Protoplasm. ( Chlorophyll grains. FIG. 2. PREPARATION FOE DIVISION. FIG. 3. Showing RESULT OF DIVISION. FIG. 4. MOTILE FORMS — ZOOSPORES OR ZOOGONIDIA — a. The protoplasm has drawn itself away from the cell-wall at all but two points. At these points two vibratile cilia protrude through the cell-wall. 1>. A naked zoospore. FIG. 5. EREMOSPHJSRA VIRIDIS, a close ally of Protococcus, containing starch granules — a. Unstained. b. Stained with iodine to bring out the starch granules. No starch is found in the Protococcus itself, probably because it uses up the starch as fast as it is manufactured. DIAGRAM OF PHYSIOLOGY — a $• b. Show that in the dark no oxygen is evolved from carbonic acid (C0j). a £ r. Show that in the light the carbonic acid is absorbed and oxygen gas given off. This process, viz. the absorption of COz and evolution of 0, is called Assimilation. Respiration is quite a different process ; it consists in the absorption of O and the evolution of COj. In the green plant these two processes go on together. CLASSIFICATION OF PROTOCOCCUS. Kingdom — Plantaj, because it possesses a cellulose wall, absorbs C02 and evolves 0. Sub-Kingdom — Thallophyta, Group — Algae. CHABA. Fio. 1 («). Showing — . f Nodes (L. nodus, a knot). 1 Internodes (L. inter, between). . f Leaves arranged in whorls. APPENDAGES < , I Branches. TERMINAL BUD < ( Nodes. BRANCH . . < Internodes. I Appendages. Nodes with their leaves. Shor.t internodes. Fio. 1 (//). Showing the CORTICAL LAYER INVESTING THE INTERNODAL CELL (L. cortex, bark). FIG. 2. TRANSVERSE SECTION OF INTERNODE. Showing — Cortex. Wall of internodal cell. Protoplasm lining the wall, the so-called primordial utricle (L. primordius, original ; utriftilits, a little bag). Chlorophyll granules arranged so as to leave an uncoloured portion, the neutral line. Inner layer of protoplasm — the moving layer. Vacuole, filled with cell-sap. FIG. 3. Showing the NODE — A surface of cells one layer thick. FIG. 4. THE TERMINAL BUD DISSECTED TO LAY BARE THE GROWING POINT. Showing — The hemispherical apical cell. It grows in length and multiplies by division transverse to the axis. The cell immediately beneath apical cell afterwards divides transversely into two portions — the lower an internode, the upper a node. The internodal cell (blue). It elongates, but does not divide at all. The nodal cell (uncoloured). It does not elongate, but divides parallel to the axis, so as to form a transverse partition of cells. Nodal cell originating a young leaf. Nodal cell originating the cortex. FIG. 5. PORTION OF LEAF. Showing — The uncovered apical or terminal cell Nodal cell. Cortex j Descending lobes. I Ascending lobes. FIG. 6. MOVEMENTS OF THE PROTOPLASM — The arrows represent the direction of the currents of protoplasm. The uncolonred bands are the neutral lines (see fig. 2). DIAGRAM I. Showing FORMATION OF CORTEX. The peripheral cells of the node (shown in fig. 3) send pockets upwards and downwards to form the ascending and descending cortical lobes. PLATE IV. Fi g . 3 . Structure, of Carpogonuun a/. Chora/ ~b . i. I Portum; vfLeat' with,' rnaZf & Large, lateral leaflet - JttffltrLduzrn; Fi ^.5. afrrmnattng Carpogotuum T^rotmbryo Fig 4-. Development of Ovpocfcrrvuxm, Cell. eiidvscd in filutntnt& , J./X'Z originating die THE BRACKEN FERN (PTERIS AQUILI N A ) Fig. 3. Partit in" the L<-af Fi4. 8. Partumi of TrvthaUu* o PLATE IV. — continued. FIG. 1. PORTION OF LEAF. Showing — Autheridium, male organ, or globule. Carpogonium, female organ, nucule, sporangium, or spore-fruit (Gr. spora, ^ seed; anyeion, a vessel). FIG. 2. THE ANTHERIDIUM DISSECTED. Showing — a. Shield. Manu'brium (L. a handle). Capitulum (L. a little head) (blue). Secondary capitula (blue). Not named on drawing. Filaments. 1>. Portion of filament, with a spermatozoid in each of its cells. c. A liberated spermatozoid, with two long cilia. FIG. 3. THE CARPOGONIUM OK NUCULE — • Central cell. Twisted filaments, quite different from the filaments of the antheridium. The one-celled corona in Chara, and the two-celled corona in Nitella. FIG. 4. DEVELOPMENT OF THE CARPOGONIUM OR SPORE-FRUIT. Sectional view. Fio. 5 and DIAGRAM I. Showing DEVELOPMENT OF THE SPORE, enclosed in sporocarp — Proembryo. Pseudo- whorl of leaves, with the Chara in its axil. CLASSIFICATION OF CHARACEJE. Kingdom — Plant*. Sub-Kingdom— Thallophyta (exceptional in having axis and appendages^. Class — Carposporese, because it has a spore fruit. Group — Algae. Order — Characea?. Genera— Chara and Nitella. THE BRACKEN FERN. Fio. 1. Showing — ( Rudimentary leaf. 1 Young leaf. LEAVES < ° 1 Cut leaf. ' Old leaf. Underground stem or rhizome (Gr. rJtiza, a root; omos, the same as) with its growing point Roots. 8 Fro. 2. LATERAL LINES OF RHIZOME. FIG. 3. Showing — ( Bachis (Gr. rachis, a spine, ridge). a. PAET OF LEAF OR FROND . . . . < Pinna (L. a feather). { Pinnule (L. pinnula, a little feather). I. Two PINNULES VIEWED FROM BELOW ( ^dusiuiii (L. induere, to clothe) covering spore-cases. ( Sorus (Gr. sons, a heap), a cluster of spore-cases. FIG. 4. Showing FORKED VENATION AND INDUSIUM. FIG. 5. SPORE-CASE OR SPORANGIUM. Showing — Stalk. Case. Aunulus (L. a ring). In c, a small part below the spores is inadvertently uncolouretl. Spores. FIG. G. SPORE. Showing — Exosporiuni (Gr. exo, outside ; spora, a seed). Endosporium (Gr. endon, within ; spora, a seed). Protoplasm with oil-globules. Nucleus. FIG. 7. DEVELOPMENT OF SPORE. Showing — «. Endosporium protruded. &. Divided to form a young prothallus, with root-hairs. c. Old prothallus with root-hairs, male organs or antheridia, and female organs or archegonia (Gr. archos, chief; gone, seed). FIG. 8. PROTHALLUS UNDER HIGH POWER. Showing — r Cell- wall. CELLS . J prot°Plasm- ' | Chlorophyll granules. l^ Large vacuoles filled with cell-sap. FEKN"(CoNTD) PLATE Fig. 2 A rcheffonui/n of Royal fern -Siftiantil £ If valiant Old Archegunuun. Yo . 4. Centnit esil t'urthtr 3. Arvhtffffntum arttr Imtiiration 7- Tnin.t .(' }.<>n1 ' thr. Khi\m/te timier t Fi 0. b Khixornf Tra Long '- Sections Epidermis & Suh-epidermi Vascular Bund I f undsrhufh pawtr: b. Lvnyit W.S AK. Jdhnmon. Edinturtfh t London. PLATE V. FBR.N continued. FIG. 1. THE ANTHERIDIUM AND ANTHEROZOIDS OF THE ROYAL FERN (Osmunda Regalis), under surface oi prothallus (green). FIG. 2. THE ARCHEGONIUM WITH ITS CENTRAL CELL OR GERM-CELL. Fio. 3. DIVISION OF CENTRAL CELL INTO FOUR IN THE BRACKEN. FIG. 4. CONNECTION OF YOUNG BRACKEN FERN WITH IT.-J PROTHALLUS BY MEANS OF THE FOOT. FIGS. 5, 6. TRANSVERSE AND LONGITUDINAL SECTIONS OF THE RHIZOME. Showing — Sc.i. Outer scleren'chy ma (Gr. skleros, hard; enchnma, tissue). G. T. Ground tissue or paren'chyma (Gr. para, together; enchuma, tissue). F.-V, B. Fibro-vaseular bundles — outer. Sc.«. Inner sclerenchyma. G. T. Ground tissue. F.- V. B. Fibro-vascular bundles — inner. FIG. 7. TRANSVERSE AND LONGITUDINAL SECTIONS OF RHIZOME. Showing — Epidermis, sub-epidermis, and parenchyma loaded with starch granules. Fibro-vascular bundle with scalariform and spiral vessels. Parenchyma with starch. Sclerenchyma very thick walled (Gr. skleros, haul). FIG. 8. PORTION OF FIBEO-VASCULAR BUNDLE. Showing — Cells of fibro-vascular bundle sheath. Cells of bast sheath with starch granules. f Bast fibres or hard bast. BAST OR PHI/EM -j Bast vessels. ) ( Bast parenchyma or procambium. J f Scalariform vessels. WOOD OR XYLEM < Spiral vessels. ( Wood parenchyma. Notf. — In the complete bundle the bast forms a ring surrounding the wood. FIG. 9. PART OF AN OBLIQUE SECTION OF A LEAF-STALK. Showing the scalariform vessels (L. srala, a ladder* of the bundle. CLASSIFICATION OF FEBN. Kingdom — Plan tie. Sub-Kingdom — Vascular Cryptogams (Gr. kruptos, hidden ; gamos, a marriage). Vascular, because they possess fibro-vascular bundles ; cryptogams, because the sexual organs are hidden on an inconspicuous prothallus. Class — Filiciuae. Order — Filicos. Oenus — Pteris (Gr. pteron, a wing). Species — Aquilina (L. aquila, an eagle). Common Name — Bracken Fern. THE FLOWERING PLANT PLATE VI. Diagram I Tkr Lrat'y Axif Tcrmutal Bwl. ' ' AxOl, Saatum, of Onum. Kind* of Leave* 11 PLATE VI. THE FLOWERING PLANT. DIAGRAM I. Showing— g, f Nodes, bearing leaves (L. nodus, a knot). I Internodes, bearing no leaves (L. inter, between ; nodus, a knot). I Leaf. APPENDAGES OF STEM < Bud, a shortened stem with crowded leaves. ( Branch, an expanded bud. p _ ( Axillary, in the angle between the leaf and stein (L. axilla, the armpit). -I OSITION OK J31JDS . \ __ , , ( Terminal. Fio. 1 (a). THE HORSE CHESTNUT. Showing — Intern odes. Nodes with leaf-scars. Two axillary buds. Terminal bud. Fio. 1 (6). THE SAME. Showing the scars left by the fulling off of the bud-scales. These scars mark the commencement of a year's growth. FIG. 2. BULB OF ONION. Showing — Stem, short. Leaves, crowded, and stored with nutriment. Buds (1) terminal and (2) axillary. Roots, fibrous. The peculiarity of the Onion is this : it remains permanently in the bud condition. A permanent bud of that kind is called a bulb. Fio. 3. Showing KINDS OF LEAVES — Scale leaves. Foliage leaves — the green leaves which manufacture starch (L. folium, the leaf). Bracts — leaves near flowers (L. bractea, a thin plate). Floral leaves (L. fos, a flower). (Red.) FIGS. 4, 5. EXAMPLES OF LEAVES — Pinnate leaf, with elongated midrib (Pea). Palmate leaf, with extremely short midrib (Horse Chestnut). Compound leaf. The incisions extending into the midrib, and subdividing one leaf into a number of leaflets. Stipules — appendages originating from the base of leaf-stalk, not from the stem. FIG. 6. Showing FOLIAGE LEAVES united or connate (L. con, together ; unfits, born). Fio. 7. FLOWER OF PEA. Showing — Sepal leaves united below (gamosepalous calyx). Petal leaves of unequal size (irregular corolla indicated in formula by V). FIG. 8. Showing GENEEAL STRUCTURE OF THE FLOWER — Calyx (Gr. kalyx, a cup). Corolla (L. corolla, a little crown). Stamens or Andrcecium \ /rl i -j ( Filament (L. ftlwn, a thread). (Gr. aner, male;ot*o«, > , . : . * , . \ Anther containing pollen-grams, house) (male. organs) J Pistil or Gyneecium (Gr. \ Ovnry containing ovules. gune, female; oikos, > Style. house (female organs) ) Stigma (Gr. stigma, a brand). FIG. 9. PLAN OF PEA FLOWER. Snowing — Calyx = five sepal leaves united. Corolla = five petal leaves separate. Andrcecium=ten stamen leaves, nine united and one free. Gynoecium=one carpel leaf. Formula V Ca. (5), Co. 5, An. (9) + 1 Gn. 1. THE FLOWERING PLANT (CONTD) PLATE VI I. D i ag . I . fiction of Flower 1 Pollen Grains Dia^.2 Stftum of Pistil Stiqrrui - - ig. 3. Trtui*vtr*t •fiction-- vt' Anthfi- at' Tulip ^ii -seed with C*TIC kali' nrnwrd of' Abimmi 3 Pea, laid uptii & Tettn rentei-ed.- * The Bean* f TheJieitJi H-uft TtfUi <&ant cotyledan c Gptykthm p. ~Pliurtulf '' Young Jkan riant -Epidermis Diag 4, ftimta&on of} -each mother &U form* 13 PLATE VIL THE FLOWERING- PLANT. DIAGKAM I. Showing— RECEPTACLE OR THALAMTTS TO WHICH THE FLORAL LKAVES ARE ATTACHED. /Calyx, hypogynons or inferior (Gr. liupo, under; gune, the female INSERTIONS OF FLORAL •\ Corolla, hypogynous or interior. I Stamens, hypogynoua ^ Ovary, superior or free, containing an erect ovule. DIAGKAM II. Showing— ( Stigma, for receiving pollen. PISTIL OR GYNCECIUM . . •< Style. V. Ovary, containing one ovule. IMPREGNATION OF OVULE Pollen-grains attached to stigma and throwing out pollen-tubes, which make their way down the style, enter the micropyle ot the ovule, and fertilize the germ-cell in the embryo-sac. DIAGKAM III. Showing - (Primine or outer coat (L. primus, first), formed after inner coat. OVULE ....... \ Secundine or inner coat (L. necumlut-; second). ( Nucleus, with a giant cell — the embryo-sac. ( Wall of sac. EMBRYO-SAC FERTILIZED -j Embryo. ( Endosperm. FIG. 1. Showing the RIPE PISTIL OF PEA — PERICARP — Ripe wall of ovary, dry and splitting into two valves. SEED — Ripe ovule. FIG. 2. Showing SEEDS — f Testa or seed-skins (L. testa, a shell). -? Endosperm, the so called albumen (Gr. endon, within; xpernia, a seed; (Albuminous Seed) ^ Embrvo> witll two cotyle'dons, or seed-leaves. ( Testa. 2. ALMOND \ „ , , , , . , .. •< Endosperm absorbed into embryo. (Exalbuminous Seed) J -p, , . , ,, ' v Embryo, with two cotyle dons. 3. PEA (Exalbuminous Seed). i E T> ( Testa. 4 and 5. BEAN . EAN ,„ ., . ,, , . < Endosperm absorbed. (Exalbuminous Seed) j -.-, , .,, . , , , ' v Embryo, witli two cotyledons. f Cotyledons. EMBRYO ...... J Plumule. ( Radicle. FIG. 3. ANTHER OP TULIP, showing fibro-vaeculai- bundle in centre corresponding to the midrib of the leaf. Right anther-lobe with two pollen-sacs. Left anther-lobe with two pollen-sacs. DIAGRAM IV. FORMATION op POLLEN-GRAINS BY ENDOGENOUS DIVISION. FIG. 4. YOUNG BEAN PLANT, showing — AYIH ! Tap-root, ( Stem with terminal bud. i Rootlets. APPENDAGES -J 2 Cotyledons. ( Foliage leaves. HISTOLOGY OF FLOWERING PLANT PLATE VIII. Diag I Tt-arurverfes accticm^ ofytmrtg ttzms afSorse. chestnut Fig.5 TraJi*vfr$e jftttums of' Leaf Fig. 3. Trajt-fv&vf section, of stern- of Rutte F.g. 7 Transvttxt .Krtian of Lent Blad& •"'. I j ^ tfciefffi cJiyr 7it>rij vascular hundte. Fig. 4 Portion; of Long1? section. azJtnterval* of a fav Stained. wuJis Jiayenfu, Fig, 4. Colourless CorpitecUs of IItm b. Treated with cuxti& acid c. Sfen at intervals of a. minute Fig I Extended slate <>T Torifc BELL ANIMALCULE (VORTICELLA 17 PLATE IX. PROTEUS ANIMALCULE. STRUCTURE — FIG. 1. Ectosarc or outer transparent border (Gr. ektos, outside ; sarx, flesh). Endosarc or inner granular portion (Gr. endon, within). Contractile vesicle or vacuole, a cavity filled with a clear fluid. Nucleus or endoplast, a roundish solid granular portion of protoplasm. Pseudopodia (Gr. pseudos, false ; pous, podos, a foot), processes of the body constantly changing. MOVEMENTS — Fio. 2. Changes of form constantly taking place, hence the name of Proteus Animalcule. Food-particles. MULTIPLICATION — FIG. 3, «. Stationary form surrounded by a structureless case or cyst. b. Mobile form escaped from cyst. c. Process of fission taking place. d. Original amoeba divided into two. CLASSIFICATION — Structural relations with other animals. Kingdom — Auimalia, because it depends on pre-formed protoplasm and docs not possess a cellulose cell-wall. Sub-Kingdom — Protozoa (Gr. prolos, first; won, an animal), because it is not differentiated into cells. Natural Order — Protoplasta (Gr. i>lastos, moulded), because it possesses a nucleus and contractile vesicle. Genus — Ameeba (Gr. amoibe, change). Common Name — Proteus Animalcule. COLOURLESS CORPUSCLES OF HUMAN BLOOD. FIG. 4, a. Structure — granular with spherical or irregular outline. b. Nucleus brought out with dilute acetic acid. c. Amoeboid movements taking place sluggishly. 18 BELL ANIMALCULE. STRUCTURE — FIG. 1. Bell-shaped body with slender stalk for attachment. / Cuticle, a very thin layer of protoplasm investing the body. Disc, covering the mouth of bell and fringed with cilia. Peristome (Gr. peri, around ; stoma, a mouth), the ciliated rim separated from the edge of the disc by a groove. Vestibulum (L. an entrance), a depression in the groove where food enters by a permanent mouth. The undigested matter passes out by a temporary anus (L. a , \ vent). (Eso'phngus or gullet, leading from vestibule into the soft body-substance. Food-vacuoles, food-particles enveloped iu water and dropped off from the end of the gullet. Contractile vesicle. \ Curved nucleus. „ f Sheath, a continuation of the cuticle. 1 Axis, the central muscular fibre. DIAGRAM OF THE PAEAMCECIUM OK SLIPPER ANIMALCULE, A FREE SWIUHING INFUSORIAN— Cuticle and cilia. Cortical layer with two contractile vesicles. Body-substance like soft-boiled sago. Funnel-shaped mouth opening by a short gullet into body-substance. Anus, merely a temporary opening. ' MOVEMENTS — • FIG. 2. The spirally-coiled stalk, the retracted disc, and the curved-in peristome. FIGS. 3, 4. Encysted forms — stalked and unstalked. Mu LTIPLIC ATION — FIG. 5. Longitudinal fission ; a bell divides lengthways into two, and the detached portion finally becomes like the original. REPRODUCTION — FIG. G. A free-swimming bell fuses with a stalked form, producing a single individual; this is the so-called process of conjugation. The attached bell was formerly taken for a bud. (Pos- terior cilia not shown.) CLASSIFICATION — Sub- Kingdom — Protozoa. Natural Order — Infusoria, because it possesses an outer layer (ectosarc) provided with cilia and contractile vesicle or vesicles, and an inner substance (endosarc) with nucleus, and usually with a mouth leading into it and an anus leading out. They occur in infusions, hence the name. Genus — Vorticella, so named from the vortex caused by the moving cilia. Common Name — Bell Animalcule. \ FRESH WATER POLYPE (HYDRA) PLATE X- Fig. I Jfyctra, viridie or Common. CrfZr oTOu. Ectoderm Fig. 2 Hydra, erLona armed, ffyctryi Fi £. 7. Jape SpcrmaJl0y*^*n' <& Ovum/ or viricti* ^Ripe-Ov C StufTTwntett 0vum.-so-eaHed, 'egg ' Diagram 2. -Development of Hydrozoa c Station ' b . Section- of Manila.' * -Qtrminol. \Germuial spot EARTH-WORM (LUMBRICUS TERRESTRlS) Fig 2._Thefi'fleen Anterior Segments -Ventral aspect. 'Mouth, 19 PLATE X. FRESH- WATER POLYPE. GENERAL CHARACTERS — FIG& 1, 2. Foot or hydrorhiza (Gr. rliizn, root) attached to some floating body. Mouth at free end. Tentacles or feelers (L. tentare, to feel) surrounding the mouth. ( Testis, the male organ. Reproductive organs j Ovary> the female ^^ Multiplication by budding or gemmation (tig. 2). GENERAL STRUCTURE — DIAO. 1. Ectoderm (Gr. ektos, outside; derma, skin) (red). Endoderm (Gr. endon, within). Body-cavity, serving also as a digestive cavity, and continued into the tentacles. MINUTE STRUCTURE OR HISTOLOGY- FIG. 3. Ectoderm-cells with contractile prolongations— neuro-muscular cell-layer. Nuclei and nematocysts in the cells. FIG. 4. Endoderm-ccll with cilium on its inner surface. FIGS. 5, 6. Thread-cells or nematocysts (Gr. ticina, thread ; kuntns, a bug), consisting of capsule, filament, and three recurved spines at base of thread. REPRODUCTION OR SEXUAL PROCESS — FIG. 7, a. Spermatozoon (Gr. sperma, seed; zoon, an animal) with oval head and vibratilo cilium. b. Eipe ovum, consisting of vitellus or yolk, germinal vesicle or nucleus, and germinal spot or nucleolus. c. Impregnated ovum divided into a number of cells, surrounded by a capsule — burst to show the contents. MULTIPLICATION OR ASEXUAL PROCESS — Process of gemmation shown in fig. 2. DEVELOPMENT OF HYDROZOA — DIAG. 2. The impregnated ovum by division becomes a mulberry-like mnss or montJa, the morula becomes hollow by the accumulation of fluid in its interim-, forming a planula, and the planula by gradual thinning opens at one end, becoming the so-called gastrula, which passes into the mature form. ffote. — In the Hydra itself there is no proper planula stage, as the two-layered form represented in c lias no cilia. CLASSIFICATION — Sub-Kingdom — Coelonterata (Gr. koilos, hollow ; entcron, an intestine), because it is composed of two cell-layers — ectoderm and endoderm — and has no cavity separate from the body- cavity. Natural Order — Hydrozoa, because a digestive sac is not marked oil' from the body-cavity, and the reproductive organs are external. Genus — Hydra. Common Name — Fresh-water Polype (Gr. polus, many ; pous, a foot). THE EARTH-WORM. EXTF.RNAL CHARACTERS — FIG. 1. The segmented body with a mouth at one end, an anus at the other, and a swollen portion called the ciugulum (L. a girdle) or clitellum (L. ditdlue, a saddle). FIG. 2. Mouth situated on the 2nd segment. External and internal pair of setse (L. seta, bristle). Openings of segmental organs, one on each side of all the segments except the two first. Openings of spermathe'cse or receptacles of the spermatozoa (Gr. tpf.rma, seed; tltel;e., a repository). Openings of vasa deferentia (L. excretory ducts) on ventral face of 15th segment Openings of oviduct on ventral face of 14th segment. EARTH WORM. (LUMBRICUS TERRESTRIS)-(Ck)HT*-) PLATE XI. Fi g. I IJaicL opt*i> iroms dorsal florsai via* thawing HeprodiLctitv Jb Diagram of Transverse Section of body thro' region of Oviduct 21 PLATE XL THE EARTH-WORM— continued. DISPOSITION OF INTERNAL GROANS — FIG. 1 and DIAGRAM — ALIMENTARY SYSTEM. BLOOD SYSTEM — CIRCULATORY • Mouth. ' Cut end of muscular pharynx. | Gullet. Crop, a dilated portion of gullet. Gizzard, whitish, thick, and muscular. Intestine leading straight to anus, and covered with a brownish mass supposed to be the liver. Colourless corpuscles in perivisceral cavity — two shown. Pseud-haemal vessels contractile, and therefore circulatory — Supra-intestinal vessel (L. supra, above). Sub-intestinal vessel (L. sub, under). Sub-neural vessel. Cominissural vessels connecting supra-intestinal and sub- /( REPRODUCTIVE SYSTEM . . -j AND RESPIRATORY . . \ intestinal vessels. Dilated commissural vessels in the region of the reproduc- tive organs, the so-called hearts. Coloured fluid without corpuscles contained in pseud-haemal vessels acts as an oxygen-carrier, and is therefore respira- tory in function. RENAL SYSTEM Segmental organs in pairs in each segment •Cerebral or prse-oral ganglia connected by commissural cords embracing the pharynx with the NERVOUS SYSTEM . . . . -^ Sub-cesophageal or post-oral ganglia which form the anterior extremity of a V Chain of ganglia extending to end of body. Ovaries and oviducts. Testes and vasa deferentia shown in fig. 2. Fios. 2, 3, 4. RENAL AND REPRODUCTIVE SYSTEMS — Segmental organs with internal ciliated opening and external pore (tig. 3). J Anterior pair of spermathecae. ( Posterior pair of spermathecae. ( Anterior pair of bilobed testes. ( Posterior pair of testes. {Anterior reservoir of testes with duct. Posterior reservoir of testes with duct. Common vasa deferentia. Capsulo-genous glands for secreting egg-capsules. Ovaries. Oviducts with wide ciliated internal opening and external opening (fig. 4). Fio. 5. Ovary with ova. When laid the eggs are enclosed in clusters within a chitinous case, each egg consisting of — Vitelline membrane. Vitellus. Germinal vesicle. Germinal spot. Spermatozoa from Spermatheca. CLASSIFICATION — Sub-Kingdom — Annelida (L. annulus, a ring), because the body is segmented ; without jointed limbs ; nervous system forms a ring round gullet, followed by a ventral chain of ganglia. Natural Order — Oligochae'ta (Gr. oligos, few ; chuite, hair), because the bristles are in rows, not tufted. Genus — Lumbricus.. Common Name — Earth-worm. LOBSTER (HOMARUS VULGARIS) PLATE XII. Fig. I. Side vie Fig. 4. ApptndcLqes of Z- Abdominal- .Vomit > J • Abdtmiirtal- SotniA*> - posterior vif\ Fig. 5 Aptpendage* Sornile - - -Opening nt' Auftitbry Jfcu' 6 ;""* fan ol' Maxilla* f. :>~* Pair arjtfcuriUi 1? Pair ,11'Va.riHae Jtmbulalory Lirni I I £pifM>dite- 23 PLATE XII. LOBSTER AND CRAYFISH. EXTERNAL CHARACTERS — FIG. 1. ENTIRE SPECIMEN — Ce'phalo-thorax (Gr. kephale, head; thorax, a breast- f °*™'<*L ™ture between head and thorax. plate) covered by Carapace . 1 Frontal sPme or rostrum SeC°nd pair' e))iP0(nte _giU-t>earing. 0 9. Third pair, epipodite gill-bearing. Chelae or pincers (Gr. elide, a claw), epipodite gill-bearing (fig. 1). 10. Ambulatory limb (L. ambulare, to walk), epipodite gill-bearing. The four pair are seen in fig. 1. ABDOMEN — six pair (see figs. 1-5). NOTE, — Seven joints of chelae and ambulatory limbs are named in order as follows (see No. 10) — 1. Coxo'podite (L. coxa, the hip) or proximal joint. 2. Basi'podite . . . • f 3. Ischio'podite (Gr. ischion, the hip) } fused ^6&cr ln chola- 4. Mero'podite (Gr. meros, the thigh). 5. Carpo'podite (Gr. karpos, wrist). 6. Pro'podite (Gr. pro, in front of). 7. Dactylo'podite (Gr. daktulos, a finger) or terminal joint. Six joints of antenna in order (see No. 3) — Coxo'cerito (Gr. keras, a horn). l.asi'cerite articulated with an outer tlat plate, scapliocerite. Ischio'cerite. Mero'corite. Carpo'cerito. Pro'cerite, the long many-jointed feeler. LOBSTER (HOMARUS VULGARIS)— CONT"- PLATE Pi 4. 1 Longitudinal Horizontal Section (Female) O K, Fig- 2 . Longitudinal Vertical Section (Male YSTFM •s I Arteries — Sternal, superior abdominal, and inferior abdominal. KESPIRATORY SYSTEM — Branchioe (Gr. gills), twenty on each side in Lobster, eighteen ill Crayfish. HENAL SYSTEM — Green glands situated at the base of antennas. ( Supra-cesophageal ganglia. ,T i Circum-cesophageal commissures. NERVOUS SYSTEM . < „ 1 Sub-cesophageal ganglia. V. Chain of eleven ganglia. ( Testt's with their vasa deferentia opening on the base of last thoracic T, appendages (llg. 2). REPRODUCTIVE SYSTEM J Ovaries with their oviducts opening on the base ot last thoracic appcn- V clages but two (fig. 3). LOBSTER (HOMARUS VULGARIS)— CoN PLATE XIV. Fig 4-. Gastric skeletons- side, vtav ~Pflort£s t>r Anterior piecA Stvcart&a& or Tb/ter Oiag. 2 Elevation &. Plan of Meart. a, . Elevation* Diag. 1. Gmdatoj-v- £c KetmraJtary Di'ag .3. Ovum* after passing through- Ovidjuwt jg. 6 Zofa, of fiobsttr -Juft left llu Fij.8 . Fi'g.S. 'iesfis &. Spermatozoon.-. Fig. 9. •f^ .nd»Ulp J^Maxitlifirdf, AJundafyuy Fi g. 7. Gnr fisk; - as tt leaver tht eg$ 27 PLATE XIV. LOBSTER AND CRAYFISH— continued. ALIMENTARY SYSTEM — FIG. 1. STOMACH in Elevation and Plan — I'E 'IONS -f Anterior or cardiac. ( Posterior or pyloric, the anterior part of which is the prepyloric. ( Cardiac region-cardiac ossicle { Trransverse Piece- SKELETON < ' ^rocardiac process, a median prolongation. } Prepyloric region — median prepyloric ossicle (green). V Pyloric region — transverse pyloric ossicle. FIGS. 2, 3, 4. DETAILED STRUCTURE OF GASTRIC SKELETON— Ossicles — Cardiac, with urocardiac process. Prepyloric (tig. 4). Pyloric (fig. 4). Lateral j Anterior pair (figs. 3 and 4). ( Posterior pair. Teeth of— Lateral posterior ossicles. Prepyloric ossicle — a single median tooth. CIRCULATORY AND RESPIRATORY SYSTEMS — DIAG. 1. CIRCULATORY AND RESPIRATORY ORGANS — Heart, rhythmically contractile and systemic — that is, it propels the blood received from the gills through the system. Pericardium, a cavity surrounding the heart. Arteries carrying the blood to — Eye, ophthalmic. Antenna, anteunary. Kest of body, sternal with { SuPerior ^dominal brand,. ( Inferior abdominal branch. Veins, gather up blood and carry it to gills for aeration. Branchio-cardiac canals, carry blood from gills to pericardium. Valvular openings, by which the blood in pericardium enters heart. Gills, each consisting of a central stem with an ascending blood-vessel on its outer side leading from venous sinus, and a descending blood-vessel on its inner side leading to branchio- cardiac canals. The stem is beset with fine filaments which repeat the structure of the stem. DIAG. 2. ELEVATION AND PLAN OF HEART — ( 1 Ophthalmic. ARTERIES -< 2 Antennary- } 2 Hepatic (Gr. hr.par, hepatos, the liver). V 1 Sternal, with its superior abdominal branch. ( 2 Superior. VALVULAR APERTURES •< 2 Lateral. (. 2 Inferior. Pericardial cavity, so-called pericardium. Fibrous tissue, two pair of bands holding heart in place. 28 « REPRODUCTIVE SYSTEM — FIG. 5. MALE ORGANS detached (seen in situ PI. XIII. fig. 2) — Testes, make spermatozoa. Yas deferens, tube for conveying spermatozoa out of body. Spermatozoon, cilia absent. DIAG. 3. OVUM OF CRAYFISH just hatched — Outer and inner membranous coats produced at one point into a process for attachment to the body of parent. Albumen. Vitelline membrane. ViteUus. DEVELOPMENT — FIG. C. Young Lobster as it emerges from egg, a zo'ea which passes by metamorphosis into adult form. FIG. 7. Young Crayfish as it emerges from egg, essentially similar to adult, no zoea stage. FIG. 8. Adult Crayfish showing appendages. FIQ. 9. Limbs used for masticatory purposes, laid out LOBSTER (HOMARUS VULGARIS)— CONT"- PLATE Fi£3 Longitudinal' AttruLffntaL Section Cor mZft- diagonal farrow fline*} fspdbj Fi$.5. One ot 'the, radiating fLbre* traced; from-' Corneas to Optic- qanaii^n/ _ Dia* I "^A Nfr-votu elfjnentt of du, Retwsi 7l£cn-nea/ of Viriebr .J-'orrruiliffn of the- Vertebrate. Eye f{6.&*fertu)al Section- ated corpuscU* ofOie Hoods, highly ma (puJi various shape* Fig. 8 Sain of Auditory Primary 7uur attaehtd; to wait oTStStA '•Secondary hairs 29 PLATE XV. continued. NERVOUS SYSTEM— FIG. 1. VENTRAL CHAIN of 13 GANGLIA united by commissures — Cerebral or supra-cesophageal ganglia anterior to gullet, giving off optic nerves. Circum-O3sophageal commissures round gullet. Sub-cesophageal ganglia posterior to gullet. 5 Eemaining thoracic ganglia, united to one another by double nerve-cords. G Abdominal ganglia, united to one another by single nerve-cords. Note. — The numbers attached to ganglia denote the cephalic, thoracic, or abdominal segments to which they belong. FIG. 2. VISCERAL NERVES in Elevation and Plan- Nerves arising from— Cerebral ganglia — A'zygos — median, and branching posteriorly to form lateral azygos. / Mandibular. COMMISSURAL GANGLLA J Antero-lateraL ) Medio-latera], (. Postero-lateral. Hepatic formed by the union of postero-lateral and lateral azygos. SENSORY ORGANS — FIGS. 3, 4. GENERAL STRUCTURE OF EYE — Cor'nea, the transparent cuticle divided into a number of fuur-sided areas or facets (fig. 4). Radiating fibres (two are coloured red). Optic nerve expanding into optic ganglion. Flexible stalk. FIG. 5. MINUTE STRUCTURE of one of the elements of the COMPOUND EYE — Cornea, f Cone. NERVOUS ELEMENTS J , } Spindle. \ Nerve-fibril continuous with ganglion. ( Investing nervous elements and ganglion. SHEATH J Outer end continuous with cornea. J Inner end continuous with adjacent sheaths, v Oval nuclei and pigment layers. DIAO. 2. FORMATION OP THE VERTEBRATE EYE — a. Optic vesicle, a hollow process of the brain, involution of integument meeting it and pushing it in. b. Crystalline lens, a detached portion of thickened integument. c. Retina, the wall of the doubled-up optic vesicle nearest the lens (red). Choroid, the wall nearest the brain (blue). Rod and cono layer of retina embedded in the choroid by obliteration of the cavity between. DIAG. 1. NERVOUS ELEMENTS OF RETINA compared with nervous elements of fig. 5 — Rod, com', and outer granular layers = cone, rod, and spindle. ' Nerve-fibrils continuous with optic ganglion in both. FIG. 6. Base of antennule cut open to show auditory sac. FIG. 7. SECTION THROTTGH AUDITORY SAO — Auditory opening. Sac, an involution of the integument lined by hairlike filaments and containing fluid and grains of sand. Auditory nerve from cerebral ganglia. FIG. 8. Hairlike filaments magnified. 30 EXOSKELETON — FIG. 9. Vertical section of shell or'exoskeleton. The epidermis thrusts off successive layers of its substance, which form a number of delicate laminoe superimposed upon one another, and this is impregnated with salts of lime. The exoskeleton thus formed is cuticular, to be distinguished from cornified epidermis, as nails, composed of modified cells, a cellular exoskeleton. CLASSIFICATION — Sub-Kingdom — Arthro'poda (Gr. arthron, a joint; pous, a foot). The body is segmented; limbs jointed ; nervous system forms a ring round gullet, followed by a ventral chain of ganglia. Natural Order — Crustacea (L. crusta, a crust), because it breathes by gills ; has two pair of antennae (lesser and greater) ; walking legs borne by thorax and abdomen. Genera — Homarus, Astacus. Common Names — Lobster, Crayfish. FRESH WATER MUSSEL (ANODONTA CYNEA). PLATE XVL . I . a1. &de> view UA rnandc &&e> remtn-cd * Dorsal vit»v-p*riwn&>xrn, i£2 » Altxifntarr Canal if JVer van* fyttem- ft&etltm pti&fvy thro Tteart Fig. 5 Organ,' of Sojana* **v-M Oia? l Trtm&trje SeraaL GlandaZar P&rtum, Fig.6. aTranwcrst Sector* t&ftfndtd with I'/'-.-htfin. c. Shod eorpuidfj - rva^uiS *. A K Jato«um Edinburgh t London 31 PLATE XVI. THE FRESH- WATER MUSSEL. GENERAL STRUCTURE OF BODY — FIG. 1, a. SIDE VIEW OF ANIMAL when left valve and left mantle-lobe are removed — Mouth, anterior. Anus, posterior. Heart, dorsal. Foot, ventral. Gills, lateral, inner and outer. Labial palps, two on each side of month. Adductor muscles, anterior and posterior, for closing the shelL Eight lobe of mantle, lateral. FIG. I, b. DORSAL VIEW OF ANIMAL, partly dissected — Heart. Pericardium. Vena cava in floor of pericardium. Organ of Bojanus beneath pericardium. Intestine entering pericardium. DIAG. 1. TRANSVERSE SECTION OF ANIMAL — Mantle-lobes, right and left, lateral extensions of the dorsal integument. Outer gill made up of two lamellae. Inner gill made up of two lamellae. Foot, median. Pericardium. ( Ventricle. Heart < ,., ( 1 wo auricles. Intestine piercing ventricle. Vena cava. Organ of Bojanus, beneath pericardium. ALIMENTARY AND NERVOUS SYSTEMS — FIG. 2, a. ALIMENTARY SYSTEM — Mantle and gills removed on left side, and coiled intestine dissected out in foot. Mouth, below anterior adductor. Gullet. Stomach. Intestine, with neural flexure. Anus, above posterior adductor. FIG. 2, a and b. NERVOUS SYSTEM DISSECTED OUT — Cerebral or cephalic ganglia, two at base of labial palps. Pedal ganglia, two united and embedded in foot. Pari'eto-splanchuic ganglia (L. parietes, walls ; Gr. splawlma, the entrails), beneath posterior adductor. Commissures uniting pedal and parieto-splanchnic with cerebral ganglia. SENSE ORGANS — FIG. 3. Cyclas cornea, a fresh-water form belonging to the same natural order as Anodon, in the foot of which the auditory organ can be conveniently examined under the microscope. FIG. 4. AUDITOKY ORGAN OF CYCLAS — Auditory sac lined with ciliated cells and containing fluid and an otolith in the centra Auditory nerve from pedal ganglion (not shown). ClBCULATOEY AND EENAL SYSTEMS — FIG. 5. THE ORGAN OF BOJANUS dissected from left side, left auricle turned up — f Auricles receiving blood from gills. HEART (Systemic) -? Ventricle with anterior aorta and posterior aorta distributing blood to the body. 32 Vena cava receiving the blood of the body which passes through the organ of Bojanus to the gills. f Transparent non glandular portion or vestibule communicating with ORGAN OF * exterior and with the BOJANUS ) Brownish glandular portion communicating with pericardium by two V. oval openings (see fig. 1, b). RESPIRATORY SYSTEM- FIG. G, a. GENERAL STRUCTURE OF GILL, section through line al in diagram 1 — Inner and outer lamellae. Partitions between lamellae — interlamellar partitions. Pairs of chitinous rods in the parallel and vertical gill-filaments, indicated by pairs of dots. FIG. G, L. MINUTE STRUCTURE OF GILL, section of lamella parallel to surface in region of chitinous rods — Gill-filament strengthened by pair of chitinous rods. Openings between filaments furnished with ciliated epithelium. Partitions between filaments, Lnterfilamentar, consisting of horizontal and obliquely crossed fibres. MUSCULAR SYSTEM - FIG. 7. MUSCLES — Anterior and posterior adductors, adductiiig or bringing together the valves. Protractor of foot. Anterior retractor of foot. Posterior retractor of foot. Smaller retractors arising near umbo, impressions only shown (fig. 8, «). EXOSKELETON — Fro. 8, b. EXTERIOR OF SHELL — Rounded anterior end, tapering posterior end. Urnbo or beak on dorsal surface of each valve towards anterior end. Concentric lines of growth. Elastic ligament behind umbones, binding the two valves together, and tending to open the valves. The hinge-line is without interlocking processes or teeth, hence the name Auodon (Gr. a, without ; odons, odontos, a tooth). FIG. 8, a. INTERIOR OF SHELL — Pallial impression indicating attachment of muscular ventral edge of mantle to shell. Anterior and posterior adductor impressions. Successive adductor impressions, extending from cavity of umbo to each adductor muscle, and indicating the travelling downwards of adductor muscles. HISTOLOGY — FIG. 9, a. Liver invests stomach, and consists of blind tubes lined with epithelial cells. b. Muscle composed of elongated nucleated cells resembling those of smooth muscle in form (PI. XXIV. fig. 7), but having the structure of striped muscle. c. Blood-corpuscles, colourless, nucleated, and amoeboid. DEVELOPMENT — FIG. 10, a. Ripe ovum with its vitelliue membrane forming a short tube at one point with an opening or micropyle. b, c. Embryo when hatched or Glochidium — b enclosed in vitelline membrane, c escaped from it. f Valves of shell triangular (see fig. 6), united at base and incurved at DIFFERENCES J apex. FROM ADULT ^ Single adductor muscle. V Byssus or beard coming off from foot CLASSIFICATION — Sub-Kingdom — Mollusca (L. mollis, soft). The body is soft and unsegmented ; possesses a shell, and three pair of nervous ganglia. Natural Order — Lamellibranchiata (L. lamella, a plate; Gr. branchia, a gill), because it has a bivalve shell ; a two-lobed mantle ; plate-like gills ; and no distinct head. Genus — Anodon'ta (Gr. a, without ; odous, odontos, a tooth). Common Name — Fresh- water Mussel. EDIBLE SNAIL (HELEX POMATIA). PLATE XVII. Httix poniatia Fig. 3. Lenqititdinal Wrtwal Rectum. of Rectum,- FiV.5. SufcoL -mass{cu>3ide. view Fig". ". 4 Dorsal via* -with thf twper surface- of mantl? turned back Fig. 12 Jtlind atd-af Follick of 'Ovoleatit frop PLATE XVII. THE EDIBLE SNAIL. EXTERNAL CHARACTERS — FIG. 1. THE SNAIL protruded from its shell — HEAD b ' I ^a*r °^ tentacles or eye-stalks with eyes. I Pair of tentacles without eyes. Foot flattened out ventrally, hence the name Gasteropod (Gr. gaster, the belly ; pous, a foot), Shell univalve and spiral. FIG. 2. SHELL — Body-whorl, the last and largest whorl with the mouth. Spire, the rest of the whorls. Five brown bands running in the direction of the spire. Lines of growth running in a longitudinal direction from apex (shown in fig. 1). GENERAL STRUCTURE OF BODY — FIG. 3. SECTION OF BODY, shell and viscera removed— Parts of body — foot, mantle, visceral sac, pulmonary chamber. BUCCAL CAVITY I Roof with horny Jaw- I Floor with odontophore (Gr. odous, odontos, a tooth ; phoree, I bear). (Esophagus. Piectum seen in section. Nervous ganglia seen in section above and below gullet. Columellar muscle attaching body to shell. FIG. 4. COMMON SNAIL with shell removed and covering of pulmonary chamber turned back — Heart consisting of auricle and ventricle. Blood-vessels ramifying in wall of pulmonary chamber. Renal organ or kidney for getting rid of nitrogenous waste. Pulmonary aperture leading into the modified mantle-cavity or pulmonary chamber, with anu« beside it. ALIMENTARY SYSTEM — FIG. 5 a. BUCCAL MASS removed from body — Protractor and retractor muscles. (Esophagus and duct of salivary gland leading from it. FIG. 5 b, and DIAG. 1. ODON'TOPHORE IN SECTION — Skeleton formed of cartilage (blue). Sub-radular membrane with its muscles (yellow). Radula (L. a scraper), the surface of sub-radular membrane beset with cuticular teeth (red). FIG. C— a. Horny upper jaw detached. b. Teeth of radula arranged in transverse rows. FIG. 7. DISSECTION FROM DORSAL SURFACE, with organs gently separated and laid out — iBuccal mass. Gullet dilating into crop. Salivary gland embracing crop. ) Stomach, with a pyloric caecum near liver. [ Liver, with coiled intestine embedded in it. CIRCULATORY SYSTEM / yentricle (™™1* not shown). ( Aorta. RESPIRATORY SYSTEM . Pulmonary chamber, with blood-vessels on wall. RENAL ORGAN . . . Nephridium (Gr. nephroi, kidneys) or kidney for getting ri4 of nitrogenous waste. 34 Ovo-testis or hermaphrodite gland embedded in liver, consisting of tubes in which ova and spermatozoa are developed. The Hind end of one of the tubes with its contained ova and sper- matozoa shown in fig. 12. Duct of ovo-testis. Albumen-gland forming an albuminous secretion. i Vas deferens or duct for conveying spermatozoa, opening into penis. EEPRODUCTIVE ORGANS Oyiduct for conveying ova> ending in yagina Spermatheca or receptaculum seminis (L. receptacle of the semen) opening into vagina. Penis with long flagellum (L. a whip), an eversible involution of the integument. Dart-sac eversible, with pointed dart ) ,. 0 ., ,. ., } peculiar to Snail family. Mucous glands J CIRCULATORY SYSTEM — DIAG. 2. COMPARATIVE VIEW OF CENTRES OF CIRCULATION in — a. Worm— Dorsal trunk with transverse vessels discharging into it. b. Anodon — Dorsal trunk dilated=the ventricle, and transverse vessels reduced to a pair forming the two auricles. c. Snail — Dorsal trunk bent upon itself =the ventricle sending blood to anterior end of body by cephalic artery, and to posterior end by abdominal artery. Transverse vessels reduced to one, the right, forming the auricle. FIG. 8. COLOURLESS CORPUSCLES OF THE BLOOD. NERVOUS SYSTEM AND SENSE ORGANS — FIG. 9. NERVOUS SYSTEM forming a ring round gullet — Cerebral or supra-cesophagcal ganglia. „ , ,. ( Pedal, anterior and united with cerebral by commissures. Sub-ccsophageal ganglia < _ ' , . .^ , .,. ( Parieto-splanchnic united with cerebral by commissures. FIG. 10. EYES, a pair, placed at end of tentacles — Sclerot'ic (Gr. sMeros, hard) passing into a cuticular cornea. Choroid, the pigmented layer. Optic nerve expanding into an outer retina, the fibres of which pass through the choroid to form an inner retina with rods and cones nearest the light. Vitreous humour (not shown). Lens. Cornea with a conjunctiva on its outer surface. FIG. 11. ORGANS OF HEARING, a pair close to pedal ganglia — Auditory canal. Sac containing fluid and otoliths. Auditory nerve from cerebral ganglia (not shown). DEVELOPMENT — DIAG. 3. EARLY STAGES OF DEVELOPMENT OF A VELIGEROUS GASTEROPOD, no evident velum in Snail — Ciliated velum, an expansion of the integument about the head. Foot developing, with operculum (L. a lid) upon it. Shell external CLASSIFICATION — Sub-Kingdom — Mollusca. Natural Order — Odonto'phora, because it has a distinct head ; and an Odontophore. Genus — Helix (Gr. a spiral), from the spiral form of the univalve shell Common Name — SnaiL EDIBLE FROG(RANA ESCULENTA) PLATE XVIII. Fid. 2. -Dias&ctijon; from, *&«- vcntratfidt, Jlfcntih. opening TJruiary bladder /collapsed// i£. I. Encteytdeds Frog dorsal, aspect "Right Auricle ofEeart -Liver -GaU, bladder Femur {posterio Diagram I. Transverse Section of Abdomen. Diagram 2. Transverse Section of Verte brate & Invertebrate dorsal, surface. 2>& , Ctrvfrro spinal nervous i^. 3. Longitudinal vertical. sAetian, with th^c parts laid. oujb. ( F Sristlf. oofsed, into AritjErior & out of Posterior nostril Br~Lft2£ passzcl'tti ' Style p into Glottis Fi g . 4-. Alimentary tonal- t iiinii.i' n Froq . 35 j PLATE XVIIL THE FROG. EXTERNAL CHARACTERS — FIG. 1. FEOG with Limbs extended — Anterior nares or external nares (L. nares, the nostrils). Eye. Tympan'ic membrane or membrana tym'pani (L. tympanum, a drum). Cutaneous pouch (L. cutis, the skin). Clo'acal aperture (L. cloaca, a sewer). r Brachium (L. the arm). \ Antebrachium (L. ante, before). FORE-LIMB < Manug (L the hand). (_ Four digits (L. digitus, the finger or toe). f Femur (L. the thigh). ) Crus (L. the leg). HlND-LlMB } Pes (L. the foot). U . Five digits. GENERAL DISPOSITION OF INTERNAL ORGANS — FIG. 2. DISSECTION from the Ventral Surface to show VISCERA, Thoracic and Abdominal — ( Ventricle. ' ( Two auricles. Lungs, right and left. Stomach and intestine. Liver with gall-bladder, pancreas, and spleen. Urinary bladder. Corpus adiposum (L. fatty body), finger-like yellow processes. Testis, only one shown. DIAG. 1. TRANSVERSE SECTION THROUGH ABDOMEN — NEURAT, CANAL containing Spinal cord. I Lining membrane or pleuropcritoneal membrane (Gr. pleuron, a rib ; peri, around ; teino, I stretch). Alimentary canal suspended by two layers of the membrane coming together in the middle line — the PLEUROPERITONE'AL CAVITY = THORACIC CAVITY lined by the pleura, and ABDOMINAL CAVITY lined by the ' peritoneum in Man. mes'entery (Gr. mesos, middle; enteron, intestine). Testes suspended in the same way by the mesorchium (Gr. orchis, a testicle). Kidneys held in place by the membrane covering their ventral faces. Sympathetic nervous system, two gangliated cords con- tained in triangular space formed by the layers of membrane converging to form mesentery. ^ Dorsal aorta. DIAG. 2. COMPARISON OP A TRANSVERSE SECTION OF A VERTEBRATE (FROG) AND AN INVERTEBBATE (LOBSTER) — Invertebrate — Vertebrate — Visceral tube only. Visceral tube. Neural tube. Notochord (Gr. notos, the back ; chortle, a string), the primitive axial column, separating the two tubes. Limbs on neural or nerve side of body. Limbs on haemal or heart side of body. 36 FIG. 3. TIIE LIMBS on the left side are removed, together with the left walls of the cerebro-spinal, thoraco-abdominal, and buccal cavities. The alimentary canal is laid out to display it to advantage — Mouth with posterior nostril, and Eustachian recess con- tinuous with tympanic cavity. Tongue turned forward to show its attachment. Teeth in upper jaw and on palate. Stomach. Small intestine succeeding stomach. Large intestine terminating in cloaca. Liver lobcd. Pancreas or "sweetbread," pale coloured, near pyloric portion of stomach. Spleen, red, near the commencement of twisted portion of intestine. \ ( Dorsal aorta. ( Inferior vena cava. ALIMENTARY SYSTEM CIRCULATORY SYSTEM RfiSPIEATORY SYSTEM ( Glottis, a slit in floor of pharynx leading into lungs. ( Left lung. Eight ovary. Oviduct, anterior coiled portion of right and terminal HENAL AND REPRODUCTIVE SYSTEMS ( dilated portion of left (see PL XXII. fig. 8). I Left kidney with ureter. | Urinary bladder, bilobed. NERVOUS SYSTEM Brain and spinal cord. SKELETON Vert'ebral column enclosing spinal cord, and Skull enclosing brain. FIG. 4. ALIMENTARY CANAL removed from body — (ESOPHAGUS or gullet communicating with pharynx. ( Cardiac or anterior portion. STOMACH •{ _ , . , ,f . , . , .. ( Pyloric portion leading into intestine. J Duode'num forming a loop with the stomach. ( Heurn, the twisted portion (Gr. eilein, to twist). LARGE INTESTINE . \ Colon, the dilated portion into which the ileum opens. ( Rectum (L. the seat) opening into cloaca. SMALL INTESTINK . EDIBLE FROG(RANA ESCULENTA)— CONT^- PLATE XIX. i£. 3 SJeuH- lateral- view Fifc 7. Vtrttbral PeJbne, GireULt - dury ^'fe " Syoid bone, or Cu/tSajft - ventraivr - I I fareUa.ye, 37 PLATE XIX. TH.B . FROG" — continued. SKELETON. %* The colours in left-hand corner of Plate refer only to SkulL THE BONY SKULL- FIG. 1. DORSAL VIEW — Exoccipitals (L. ex, out ; occiput, the back of the head). Pro-otics (Or. pro, in front of ; ous, otos, the ear). Parietals (L. paries, a wall) . . ) Frontals (L. front, the forehead) } unlte Nasals. Premaxillte (L. prce, before ; maxilla, the upper jaw). FIG. 2. VENTRAL VIEW, lower jaw removed — Parasphen'oid (Gr. sphen, a wedge). Sphenethmoid or girdle-bone. Voniers with teeth. Premaxillas with teeth. Pterygoids (Gr. pteron, a wiug). Palatines, slender palate bones. FIG. 3. SIDE VIEW — Squamosals. Quadra to-j ugals. Maxillae with teeth. PremaxillDe with teeth. Mandible or lower jaw, consisting of two raini (L. ramus, a branch) without teetli. f Meckel's cartilage forming the core. ) Angulo-splenial . . ) . •j Dentary without teeth j lnvestlnS Meckel's cartilage. V, Mento-Meckelian bone (L. mentum, the chin), the ossified tip of Meckel's cartilage. FIG. 4. POSTERIOR VIEW — Exoccipitals with condyles (Gr. kondulos, a knuckle) for articulation' with vertebral column. Foramen magnum (L. great opening), through which spinal cord passes into brain. THE CARTILAGINOUS SKULL — FIG. 5. DORSAL VIEW— Sphenethmoid bone, replacing cartilage and partly covered by the frontala (see fig. 1). Nasal roof covered by nasals. Fontanelles, membranous portions. FIG. 6. VENTRAL VIEW — Sphenethmoid bone. Nasal floor anterior to Sphenethmoid covered by vomers. Floor posterior to Sphenethmoid from the exoccipitals covered by the parasphenoid, which partly overlaps Sphenethmoid. Pterygoid bar, replaced by pterygoid and palatine bones (see fig. 2). FIGS. 5, 6. MANDIBULAR SUSPENSORIUM, connecting lower jaw with skull — Posterior end articulating with Meckel's cartilage. Anterior end dividing j" Dorsal process or eras attached to outer wall of skull. into ( Ventral process or eras continuous with pterygoid bar. . — Two kinds of bone are distinguished in the skull according to their mode of origin — 1. Cartilage bones (red), as the name denotes, are first modelled in cartilage. 2. Membrane or splint bones (blue) are those not so preformed in cartilage. 38 FIGS. 7, 8, 9. THE VEETEBEAL COLUMN or BACKBONE = 9 bony segments or vertebra and a bony prolongation or urostyle (Gr. oura, a tail) — ( Body or centrum. VEETEBEA . . . . \ ( Neural spine or spinous process. (. Neural arch -< Transverse processes. ( Zygapo'physes (Gr. zugos, an articulation). ATLAS or 1st vertebra with which the two occipital condyles of the skull articulate. SACEUM or 9th vertebra with which the pelvic girdle articulates. f Thickened anterior end with two concavities into which the two con- J vexities of the sacrum fit (fig. 9, a). UEOSTYLE or COCCYX < gciatjc nerve) the nerve of the leg, passing out from neural canal by a (. small opening (red). FIG. 10. PELVIC AECH, side view — rAcetab'ulum, the socket into which the head of the thigh-bone or femur fits. PELVIC AECH or HIP- I Ilium or haunch-bone articulating with sacrum. GIKDLE . . . . | Ischium, a posterior rounded bone. Pubis, a ventral wedge between ilium and ischium. I^Triradiate junction of the three bones in the acetabulum. FIG. 11. HYOID— BODY. ( Anterior attached to skull (see fig. 2). PROCESSES OE COENUA J Lateral. (L. horns) . . . j Posterior. V Thyro-hyals, sometimes called posterior cornua. FIG. 12. STERNUM and SHOULDER-GIRDLE — STERNUM or BREAST- f Anterior piece— Omo-sternum (Gr. omos, the shoulder). „ -< Median piece — Sternum proper. V Posterior piece — Xiphi-sternum (Gr. xiphos, a sword). SGlenoidal cavity, the socket into which the head of the humerus fits. Dorsal portion — Scapula or shoulder-blade, and Supra-scapula. SHOULDER-GIRDLE J _ f Coracoids. f Ventral portions •{ r,, • , „ , V i Clavicle or collar-bone. FIG. 1 3. RIGHT FORE-LIMB, dorsal surface — Humerus. Radius and ulna united. Carpals or wrist-bones. Five digits consisting of nietacarpals and phalanges (first digit rudimeutary=Pollex, L. thumb). FIG. 14. LEFT HIND-LIMB, dorsal surface — Femur or thigh-bone. Tibia and fibula united. Tarsals with elongated astragalus and calcaneum. Five digits consisting of metatarsals and phalanges. Calcar (L. a spur), a horny projection at base of first digit or hallux (L. hallex, the big toe). DIAGRAM. THE CORRESPONDING BONES IN THE FORE AND HIND LIMBS WITH THEIR RESPECTIVE ARCHES — The axis (an imaginary line passing through the middle of the limb to the end of the third digit) divides the limb into a preaxial and a.postaxial portion. Carpus or tarsus consists of two rows of bones with a centrale between, and the following are thus named in human anatomy : — Radiale = Scaphoid. Tibiale I_A > i Intermedium = Lunar. Intermedium j ~ Ulnare =Cu'neiform. Fibulare =Calca'neum. Centrale, not represented. Centrale =Navicula're. EDIBLE FROG(RANA ESCU LENTA)— CONT°- PLATE XX. Fig. 1. Artfrix* - ventral al Jugular fruumtmafa i jugular ia^. 2 Trunaa ta^enoeus laid, opa Wb of tool. &htjhtiy g2^1- Fi* 4-. PurtiurL ofCafrittarv Cartilages of Larynx Sutrruo hyouL 39 PLATE XX. THE FKOG-— continued. ClECDLATORY SYSTEM — Fio. 1. ARTERIES — f Lingual artery (L. lingua, the tongue) to tongue. CAROT'ID TRUNK OR AN- J Carotid gland. TERIOR AORTIC ARCH ) Carotid artery to head by way of ear (Gr. kara, the head ; oils, the (. ear). / Vertebral artery to vertebral column. Sub-clavian artery (L. sub, under; clavicula, collar-bone) to foreliinb. CEsophageal artery to gullet. Coeliac artery ( Hepatic to liver. (Gr. koilia, the belly) ( Gastric to stomach. ( Splenic to spleen. ( Haemal to intestine (not named). Dorsal aorta, giving off branches to various organs. Common iliac arteries formed by the forking of the aorta in the neighbourhood of the ilium, and giving off hypogastric branches to the bladder and lower parts of the belly. Femoral and sciatic arteries, a continuation of the common iliac down the thigh. AORTIC TRUNK OR MIDDLE AORTIC ARCH Mesenteric artery PULMO-CUTANEOUS TRUNK OR POS- TERIOR AORTIC ARCH . . . Fio. 2. VEINS — J Pul'monary artery to lung (L. pulmo, a lung). "} Cutaneous artery to the skin of the back (L. cutis, the skin). ( Innominate, formed by / Internal jugular. SUPERIOR VENA CAVA, ) • Sub-scapular. FORMED BY . . . j Sub-clavian, formed by | ^ External jugular. Musculo-cutaneous. Brachial. T -- ( Renal. INFERIOR VENA CAVA, I «..,/.. \ -; Genital (not shown). (. Hepat'ic. FORMED BY COMMON ILIAC or RENAL AFFERENT VEIN formed by the dorsal ends of the pelvic vein, which is formed by the femoral and sciatic veins. Dorso-lumbar vein opens into common iliac. ANTERIOR ABDOMINAL VEIN formed by the ventral ends of the pelvic vein. {Gastric. Lieno-intestinal (L. lienis, the spleen). COMMON PULMONARY VEIN formed by the veins of the right and left lungs. DIAGRAM I. THE HEART, with the principal vessels distributing and returning the blood— C Sinus venosus (L. venous sinus) receiving superior and inferior venae cavae. HEART •{ Right auricle with sinus venosus opening into it Left auricle receiving common pulmonary vein. L. Ventricle leading into truncus arteriosus (L. arterial trunk). 40 PRINCIPAL VENOUS TRUNKS < ( Carotid supplying the parts about the head, including the brain. PRINCIPAL ARTERIAL TRUNKS 1 Pulmo-cutaneous supplying the lungs and dorsal integument. (. Aortic supplying the rest of the body. 'Superior cava returning blood from the head, forelimbs, and dorsal integument chiefly. Pulmonary veins returning blood from the lungs. Vena portoe returning blood from the stomach, intestine, spleen and pancreas to liver. Anterior abdominal returning blood from the urinary bladder and belly- walls to liver. Inferior cava returning blood from the hind-limbs, kidneys, and liver chiefly. DIAGRAM II. TRUNCUS ARTERIOSUS laid open to show action of heart — Pylangium (Gr. pule, gate ; angeion, a vessel), or receiving part, contains a median longitudinal valve or movable partition attached to the dorsal surface, and a small transverse valve on the right side. Synangium (Gr. sun, together), or distributing terminal part, gives rise to Pulmo-cutaneous, Aortic, and Carotid trunks. FIGS. 3, 4. CIRCULATION OF THE BLOOD IN THE WEB — Arteries with flow of blood towards the smaller branches. Capillaries arising from the ultimate branches of the arteries and giving rise to the veins. Veins with flow of blood from smaller to larger vessels. Oval blood-corpuscles coursing through the vessels. Pigment-cells on the surface RESPIRATORY SYSTEM — • FIGS. 5, 6. STRUCTURE AND FRAMEWORK of the Piespiratory Organs — FIG. 5. Glottis (Gr. glotta, the tongue), a longitudinal slit opening into the floor of the back part of the mouth or pharynx (PI. XVIII. Fig. 3). Arytenoid cartilages, one on each side of the glottis, movable inwards and outwards. Laryngo-trachcal cartilage, a ring forming the very short tube common to the two lungs. FIG. 6. The Lung is a thin-walled, elastic, and transparent bag, the inner surface of which shows shallow depressions produced by infoldings of the wall, and corresponding to the air- cells of higher animals. MUSCLES of the throat for depressing and raising the floor of the mouth— inspiratory muscles. ( Mylo-hyoid (Gr. mule, a mill), insertion in rami of mandible. MUSCLES HAVING THEIR I /,./.,. ,. . , . , ,.,, ,• i Gemo-hyoid, insertion in symphysis of mandible or chin. "ORIGIN" IN ANTERIOR -< TT , J . . .. ) Hyo-glossus (Gr. glossa, the tongue), insertion in tongue. ^ Petro-hyoid, insertion in auditory capsule. FIG. 7. PORTION OF HYOID MUSCLES HAVING THEIR "IN- SERTION" IN POSTERIOR PORTION OF HYOID . . ^ ^ , ., ,„ , ,, \ ... I Omo-hyoid (Gr. omos, the shoulder), origin m scapula. }•„. , .j ... 1 Sterno-hyoid. origin in sternum. ) NOTE. — The point of attachment comparatively fixed is called the Origin of the Muscle, while the attachment to the part to Iw moved is called its Insertion. EDIBLE FROG(RANA ESCULENTA)— CONT"- PLATE XXI. Ft J. I . Brain - Jttrvttl aspett Oia.t. Fig 4. Jtratn & fywalceni ! vertifnl motion #etu* . Longitudinal OPTIV of ' Iter a- ttrtto Ltd- - a rtttrn, TeftfrLeoEUfi Principal Cranial ntrvt* *sfctfti fivm the left., ftdr. if- ftr Oiig.2. TntnjvtrM Sietion ot'Jpwal Card * ffetiral Arruhrund atfr investing Spatial Ctrrd j£ 7 Superficial cf 'jScu-ton rJiddu£t0r brfvia '.Adihuiar magnu* i«. 9 ******* of*** ***** 41 PLATE XXI. THE FROG" — continued. NERVOUS SYSTEM — FIGS. I, 2. THE BRAIN or ENCEPH'ALON (Gr. en, in ; kephaJf, the head) — rOlfactory lobes or Rhinenceph'alon (Gr. rhis, rhinos, the nose) giving off I olfactory nerves. J Cerebral hemispheres or Prosenceph'alon ((Jr. pros, before) conii>letcly 1 separated by the great fissure (fig. 3). j Optic thalanii (Gr. thalamos, a bed), one on eacli side bounding the third L ventricle with pineal gland on roof.=Thalainenceph'alon. MID-BRAIN ( Optic lobes above and crura cerebri (L. legs of the cerebrum) below. = (Yellow) ( Mesenceph'alon (Gr. meson, middle). f Cerebellum (L. the little brain), very suialL=Metenceph'alon ((Jr. nitta, \ behind). I Medulla oblongata (L. elongated marrow) with the fourth ventricle. = V Myelonceph'alon (Gr. muelos, marrow). Lamina terminally (L. terminal plate), the anterior wall of the thalamencephalon ter- minating the axial portion of the brain, the hemispheres being lateral expansions. FIG. 3. THE CAVITIES OF THE DRAIN, so-called Ventricles — 1. Olfactory. 2. Lateral . ) 3 Tl ' -d t • -1 f Aperture °* communication, foramen of Munro. Iter a tertio ad quartum veiitriuuluui (L. passage from, third to fourth ventricle), with ventricles of optic lobes entering it. 4. Fourth ventricle, continuous with central canal of spinal cord. Fio. 4. GENERAL VIEW OF THE BKAIN AND SPINAL CORD, cerebro-spinal axis- Brain showing chiasma (Gr. a crossing) of the optic nerves, and optic tracts leading from optic lobes. Spinal cord or myelon, tapering away to the filum terminale (L. terminal thread). DIAG. 1. Ten pair of CRANIAL NERVES, ten pair of SPINAL NERVES, and ten pair of SYMPATHETIC GANGLIA — CRANIAL NERVES, 1 to 10 (yellow). Spinal 1, hypoglossal (Gr. kupo, under ; ylossa, a tongue), distributed to tongue. „ 2 and 3, forming a brachial plexus (L. bmchium, an arm ; plexus, a junction), and distributed to fore-limbs. SPINAL NERVES (Blue) / „ 4, 5, and C, distributed to the body-walls. „ 7, 8, and 9, forming a lumbo-sacral plexus (L. lumlxts, the loin), and distributed to posterior portion of body and hind-limbs ; crural to front of limb and sciatic (contraction for ischiatic) to back of it. 10, distributed to parts about coccyx. SYMPATHETIC GANGLIA (S. 1 to S. 10), with connecting commissures (red). DIAG. 2. CONTENTS OP NEURAL CANAL, as seen in a transverse section— fGrey matter, a central square with its four corners passing into the posterior (dorsal) and anterior (ventral) roots of the nerve-trunk. SPINAL CORD •{ Central canal lined with epithelium. ... f Posterior fissure (dorsal). vV lute matter outside grey matter -; l^ ( Anterior fissure (ventral). 42 fPia mater, a vascular membrane investing cord and continuous with MEMBRANES LINING I Dura mater lining canal ^red)< IN" I Arachnoid superficial to pia mater and dura mater, and secreting arachnoid VESTING CORD ^ fluid (blue). Fro. 5 and DIAG. 3. CRANIAL NERVES, and their distribution — I. Olfactory (L. oleo, I smell) distributed to olfactory sac, as shown in Diag. 1. II. Optic distributed to eye (Diag. 3). III. Oculo-motor (L. oculus, eye ; motor, mover) distributed to four muscles of eye (Diag. 3). IV. Pathetic distributed to superior oblique muscle (Diag. 3). V. Trigeminal dilates into Gasserian ganglion giving off — V1. Orbito-nasal or ophthalmic distributed chiefly to the nasal chamber. V2. Superior maxillary distributed to upper jaw. V3. Inferior maxillary or mandibular distributed to lower jaw or mandible. VI. Abducens (L. abduco, I draw away) distributed to external rectus muscle (Diag. 3). VII. Facial or portio dura (blue) dividing at Gasserian ganglion into — VII". Or anterior distributed chiefly to the palate. VIP. Or posterior dividing into a branch to the hyoid and a branch to mandible by way of tympanic cavity = chorda tympani (L. cord of the drum). VIII. Auditory or portio mollis distributed to the auditory capsule (Diag. 1). IX. Glossopharynge'al (Gr. glossa, the tongue ; pliarunx, the throat) distributed to tongue and pharynx (yellow). X. Pncumogastric (Gr. iJtwimon, the lungs; gaster, the stomach) or Vagus (L. wandering) (red)— X1. Cutaneous branch distributed to dorsal integument. X'-'. Cardiac branch distributed to heart. X3. Laryngeal branch distributed to larynx. X4. Pulmouic branch distributed to lungs. X°. Gastric branch distributed to gullet and stomach. FIG. G. N EiiVES OP HiND-LiMB, bones displaced to show nerves of dorsal surface — • SCIATIC I Perone'al (Gr. perone, the fibula) running beside peroneus muscle. 1 Posterior tibial running besido tibialis posticus muscle. MUSCULAR SYSTEM— DIAG. 3. MUSCLES OF EYE. FIG. 7. SUPERFICIAL MUSCLES OF HIND-LIMB. Frog dissected when laid on back, with dorsal surface of foot uppermost. Name. Origin. Insertion. Adductores — brevis, magnus, and Pelvis. Femur. longus. Sartorius. TIIIGH LEG Kectus interims major. Rectus internus minor. Vastus internus. ( Gastrocnemius, the bulk of the calf of the leg (Gr. gaster, the belly; kneme, the leg). Tibialis posticus (L. posterior tibial). Peroue'us. Tibialis anticus (L. anterior tibial). Extensor cruris breris (L. short extender of the leg). Flexor tarsi anterior (L. anterior bender of the tarsus). Pubis. Pubis. Pelvis. Pelvis', near to hip-joint. Partly fp.mur, partly crus. Crus. Femur. Femur. Femur. Femur. Crus, inner side of knee-joint. Do. Do. Do. Ending in tendo Achillis. Astragalus. Calcaneum. Astragalus and calcaneum. Crus. Astragalus. 43 Name. Origin. Fia. 8. DEEP MUSCLES on front or ventral surface of thigh — Pectin'eus. Pelvis. Adductor brevis, also seen on surface. Semitendinosus. Pelvis. Vastus internus, also seen on surface. Fio. 9. MUSCLES on back of thigh — for dissection lay out as in PI. XVIII. fig. 1 {Vastus internus. ""] licctus femoris „ . anticus (not ?• Pelvis. v I shown). Vastus extcrnus. J Glutas'us (Gr. gloutos, the buttock). Pelvis. Pyriformis. Urostylc. Biceps femoris (L. biceps, having two heads). Pelvis. Semimembranosus. Pelvis. Rnctus internus, seen also on front. Insertion. Femur. Crus. Cms. Femur. Femur. Femur. Crus and femur, round knee-joint EDIBLE FROG (RANA ESCULENTA) PLATE XX1L , Antero posterior Section of Kye/ oC Oac. feeTi'frvrn-bthiTui c 7ostzri0rhalf-seen,fror7t>-tfiejfraTct Fii-6. GflumeHtis auris FI6.2 AuJilorf rtqion - side, viat »f uataruJ parb. •f •? Fig. 8 Renat £ Refrroducbi't> OO\?\ FiJ.IO Section, of Urmiferaus lulnjlt Fi6. 15 Tadpole* further advafuxfL 45 PLATE XXII. THE F-RiOGr — continued. SENSE ORGANS — FIG. 1. EYE OF Ox divided— (a) Into a right and left half — left half shown. (b, c) Along equator into an anterior and posterior half. Sclerotic or outer coat passing into transparent cornea in front. Ghoroid coat pigmented, anterior end raised into longitudinal plaits — the ciliary processes. Iris (L. a rainbow), anterior to ciliary processes, and connected to sclerotic where it passes into cornea by the ciliary muscle. Lens enclosed in capsule, which is attached to the inner side of the choroid by suspensory ligament. Ciliary muscle dips into folds ol ciliary processes above, just as suspensory ligament dips into them below (b). Aqueous humour anterior to lens. Vitreous humour posterior to lens. Eetina inside clioroid. Optic nerve entering a little to one side of axis by the optic pore. Fio. 1 c. Blood-vessels are seen to enter retina from the spot where optic nerve enters. Fio. 2. GENERAL VIEW OP EIGHT EAR OF FROG — Tympanic cavity exposed by removing tympanic membrane. Three semicircular canals. Columella auris (L. little column of the ear). FIG. 3. MEMBRANOUS LABYRINTH OP LEFT EAR — Semicircular canals, anterior, posterior, and horizontal, each dilated at one end into ampullae (L. ampullor, I swell out), and two ends of vertical canals joining together. v .. . ( Utriculus (L. a little bag), into which semicircular canals open. ' ' \ Sacculus (L. a small bag). Cochlea (L. a snail's shell), rudimentary. FIG. 4. ESSENTIAL PARTS OP HUMAN EAR, natural size — External ear — Pinna or concha (L. a shell), not shown. , Auditory meatus (L. a canal). Tympanic membrane. Tympanic cavity or tympanum opening by Eustachian tube into pharynx. f Malleus (L. a hammer). -| Incus (L. an anvil). V. Stapes (L. a stirrup). Fenes'tra ovalis (L. oval window), an oval membrane, to which foot-plate of stapes is attached. Fenestra rotunda (L. round window), at the base of cochlea. ( Semicircular canals, horizontal not shown. Internal ear or 1 T, ... , . . ... labyrinth ) Vestibule into which canals open. (. Cochlea, also communicating with vestibule. FIG. 5. AUDITORY OSSICLES OF HUMAN EAR, magnified. FIG. 6. COLUMELLA AURIS detached (see also fig. 2)— Stapes or inner end fits into fenestra ovalis. Extra-stapedial or onter end attached to tympanic membrane. Middle ear Auditory ossicles or ear-bones bridging over cavity -| Incus (L. an anvil). 46 RENAL AND REPRODUCTIVE ORGANS — FIQ. 7. MALE ORGANS from the ventral surface. The right tcstis is turned over to show its efferent ducts — Testes on the ventral side of kidneys. Vasa efferentia (L. afferent vessels), leading to inner side of kidney. Kidneys in the dorsal part of abdominal cavity. Duct passing from outer side of kidney to open into cloaca — Genito-urinary canal, because it serves as ureter for the kidney and vas deferens for the testis. FIG. 8. FEMALE ORGANS removed from body — Ovary much folded and distended with ova. Oviduct distinct from ovary, anterior end opening beside gullet, posterior end in cloaca. Ureter slender and opening into cloaca, posteriorly to oviduct. Openings into cloaca — Rectum. Urinary bladder, on ventral side of rectum independent of ureter. Oviduct, anterior to opening of ureter. Ureter. FIGS. 9, 10. MALPIGHIAN CAPSULE OF HUMAN KIDNEY— Tubule with its rounded dilatation, the Malpighian capsule. Glomer'ulus (L. a ball), the tuft of looped capillaries formed by afferent vessel from renal artery, and uniting again to form an efferent vessel (vein), which breaks up into capil- laries on the wall of the tubule. Epithelium of capsule, glomerulus, and tubule. FIG. 11. MALPIGHIAN CAPSULE OF FROG'S KIDNEY — Epithelium lining tubule, with cilia to expel the urine. FIG. 12. OVUM AND SPERMATOZOON OF COMMON FROG — Spermatozoon with vibratile tail. Tadpole or Larval Frog at different Stages. FIGS. 13, 14. EXTERNAL BRANCHIAE, three on each side of neck. Suckers, dilatations of the integument secreting a sticky substance. Horny jaws. Operculum or gill-cover beginning to form. FIG. 15. OPERCULUM grown over gills, leaving only a small opening on left side for some time. Hind-limbs appearing at first as tubercles, fore-limbs hidden by operculum. FIG. 16. HEAD OF VERY YOUNG TADPOLE, magnified — Visceral clefts, six on each side of neck. External branchiae, two on each side of neck (a third pair afterwards developed EDIBLE FROG(RANA ESCU LENTA)— CONT"- PLATE XXIII, i6.2. Process of TeUc, dcri^um, •© a/ler passing through. Oviduct at- rights angles £0 thf.' furrows on. tfiar fast I J)tveloptttmt of KmJrryo — neural, caned eru-^uxtt f. olurrmar-outfr surface- of &. G&ateci -- roof of r Fij.7. TfrticaL seetum/ of Epidermis of Frog TtrtitdL Section^ of EpMutiurrv of FiJ. 6 Comtcetives Ti**ii*' - tissue- &. 7*Mow ela*ti& tissue- of thf' e* branched, ligament* bc&vetn, tfu. -vertebra*, White nbrau* ti^suf of tendon, tip of treart Ixmv of frog V It A K. JaJm-ton. Ecbnburoh. 1 L 47 PLATE XXIII. THE FROGr continued. DEVELOPMENT — Fiu. 1. EGGS, natural size (see PI. XXII. fig. 12, Egg magnified) — a. Ovarian ova. 6. Laid eggs, surrounded by successive layers of albumen or white of egg secreted by the oviduct and swelling up in water. FIG. 2. IMPREGNATED EGG showing successive stages in the process of yelk-division — The immediate result of this process is the formation of a morula (/), which by the soaking in of fluid into its interior becomes a hollow sphere. 1)1 v;. 1. DEVELOPMENT OF TADPOLE — ( Outer layer or epiblast. a. Blastoderm or germinal membrane < Middle layer or mesoblast. (, Inner layer or hypoblast (blue). Medullary groove, a median longitudinal depression. Laminae dorsales (L. dorsal plates) or medullary folds, the epiblast raised up into folds on each side of medullary groove. Notochord or chorda dorsalis, the primitive axial column. (1. Neural canal formed by the union of the dorsal lamina;, with neural arches* in its walls. Centra of spinal column invest notochord, which persists both in the centres of the bodies of the vertebrae and in. the urostyle. /. Spirally-coiled intestine. Large muscular tail. Chief phases in life of Tadpole shown in PI. XXII. Fiu. 3. Perfect Frog, tailless, in natural position. CLASSIFICATION — Sub-Kingdom — Vertebrata, because it possesses a vertebral column ; limbs with an internal skeleton ; and a portal vein with a capillary network at both its ends, receiving the capillaries of the alimentary canal, and distributing to the capillaries of the liver. Class — Amphibia (Gr. amphi, both ; bios, life), because as a Tadpole it has gills, afterwards lungs ; two condyles on the skull for articulation with the vertebral column ; and a cloaca. Natural Order — Anou'ra (Gr. a, without ; oura, a tail), because devoid of tail and gills in adult life. Genus — Kana. Common Name — Frog. Comparative Histology of Prog and Man. FIGS. 4, 4a. BLOOD-CORPUSCLES — f Frog — large, oval, and nucleated. ( Human — smaller, round, and non-nucleated. Colourless, like amoebae (see PI. IX. tig. 4). FIGS. 5, 5a. EPITHELIUM (Gr. epi, upon ; thallo, I grow) in its principal varieties — a. Squamous (L. squama, a scale) or scaly. b. Columnar or cylindrical. c. Ciliated. Spheroidal or gland ular (see PI. XXII. fig. 11). FIG. C. a, b, c. CONNECTIVE TISSUE in its two principal varieties — „. ( Connective-tissue corpuscles, nucleated cells. WHITE FIBROUS TISSUE J , ( Matrix, fibrous. YELLOW ELASTIC TISSUE, resisting acetic acid. FIG. 7 and DIAG. 2. VERTICAL SECTION OF EPIDERMIS OR EPITHELIUM. FIG. 8. a, b. CARTILAGE or GRIHTLK — ( Matrix, granular. Cartilage •{ ~ ... . . , I Cartilage- cells, nucleated. EDIBLE FROG(RANA ESCULENTA)— CONT»- PLATE Fig. I Tranxverat Section, of Femur of frog . Long ^ section; of SumAn. Ai *WA, *&('.* '" " "*'-!* /'-"j '^^^^^^ W/& Fig. + fttmz Cfll. OL , oftn&u Bony matter- oi^isi Fig.7, Smooth* nax^cuiar fibres rig. 8 l^mjfflS5SSS' a-Jsr^/aw**,*, * a,-. Striped- tnusrJe- of'/'rtta Fig. 6 Striped; human ;T Oval nurlsL m/ thfs substances ofth*, fibre Fig. 9 W