(Blasaow presented t/ So - /<^oy . ^ — DESCRIPTIVE AND ILLUSTRATED CATALOGUE OF THE PHYSIOLOGICAL SERIES ov COMPARATIVE ANATOMY CONTAINED IN THE MUSEUM OF THE EOYAL COLLEGE OE SURGEONS OE ENGLAND. VOL. I. SECOND EDITION. LONDON: PRINTED FOR THE COLLEGE ; AND SOLD BY TAYLOE AND FKANCIS, RED LION COURT, FLEET STREET. MDCXX30. PKINTED bY TAYLOR AND FRANCIS, REn LrfiN couuT, fleet stkeet. PREFACE TO THB FIRST EDITION, The Council of the Royal College of Surgeons now present to the public the fifth and last volume of the descriptive and illustrated Catalogue of the Physiological series of Compa- rative Anatomy contained in the Museum: thus completing an important design, vrhich Mr. Hunter was prevented from accom- plishing by his sudden death. The primary objects of the Catalogue have been, to give a clear and succinct description of each preparation, to determine the species of animal or plant to which it belongs, to place it rightly in the proper series, and thus to aflPord to the visitor of the Museum every facility for studying and understanding this important department of the collection. Before the formation of the present catalogue, the printed works, from which information could be derived respecting the physiological collection, consisted of the published writings of Mr, Hunter, the subjoined Synopsis of the Hunterian collection, and the Lectures on Comparative Anatomy by Sir Everard Home. The latter jjrofess to explain the Hunterian collection ; but they contain descriptions of a small number only of the preparations, and these descriptions are unaccompanied by any reference to the particular specimens. a2 iv The 'Synopsis' is here reprinted *, because it exhibits the arrangement of the physiological series which preceded that adopted in the present catalogue ; and, while it indicates the nature and extent of the changes which have been introduced, enables the scientific reader to understand more readily the reasons that are given t'or theiu. Th(( altei-ations consist, for the most part, of a return to the ai-rangement originally em- ployed by Mr, Hunter, and have been either suggested by the Hunterian manuscri]it catalogues, or made with the view of obtaining greater simplicity and consistency, and a more regular subordination in the several groups of preparations. The Hanterian documents, for example, seemed clearly to show that it was not the intention of the foundei- to place the preparations of ' Elastic substance as a substitute for muscle f ' in a subseries distinct and remote from that which illustrated ' Elasticity in aid of muscular action J.' No adequate advantage was gained by retaining the subseries of ' Gizzards § ' distinct from that of ' Stomachs with a superadded crop \\' The physiological relation of these cavities to each other, and the modifications of a single and definite plan of gastric structure, were obviously better illustrated by retaining in the same series all the grada- tions of complexity in the stomachs of birds, which form the most natural and best defined class in the animal kingdom. As the progress of science is chiefly characterized by the reduction of supposed anomalies to recognized general prin- ciples, the physiologist, who may compare the present with the preceding arrangement of the physiological collection, will not be surprised at the suppression of many of the groups of prepa- rations which formerly swelled the series entitled ' Peculiarities in vegetables and animals^.' Osseous substance, for example, is a material of the frame- work, not of animals in general, but of one only of the primary groups of the class ; the substances, therefore, ' of which the * [Omitted.] \ Subseries 5. II Subseries 23. + Subseries 17 of the Synopsis. § Subseries 28. H Series XII, V skeleton is composed in animals not having bone as the shells and their opercula f in MoUusks ; the calcareous crusts and horn-like coverings of the Articulate animals ; the corals and madi'eporic secretions o£ Zoophytes, for the defence and support of their delicate gelatinous organs, cannot be regarded as ' Peculiarities,^ but as essential members of the normal system of organs of support, equivalent to the bones of the vertebrate animals. The subseries numbered 116, 139, and 140 in the synopsis, have, therefore, been removed from the series of pecu- liarities, and made to precede the parts of the skeletons of the Vertebrata in the first subdivision of the present arrangement. Changes in the second division of the physiological collection have been made in conformity with the same principles that have regulated the alterations from the arrangement of the synopsis, already noticed ; and chiefly consist in the reduction of the formerly extensive series of ' Foetal peculiarities.' For as every condition that characterizes the progress of the germ to its extrication from the foetal coverings^ or which disappears during that progress, or is suppressed after birth, may be termed a ' foetal peculiarity,' numerous preparations had been transferred from the older series illustrative of the phfenomena of foetal de- velopment in different classes of animals, and had been brought together in the twentieth series of the arrangement of 1818, in contravention of the special purpose of such older series. Certain stages, for example, in the formation of the vitelline sac, exhi- biting as many modifications of its relation to the embryo, were shown in one series of preparations J ; other stages were exhi- bited in another series § ; and a later condition, under the title o£ 'Yolk received into the stomach ||,' formed a third separate group. All such specimens have been brought together in the present arrangement and placed in a consecutively ascending order, subdivided only according to the class of animals, the evolution of which such preparations successively illustrate. * Subseries 116. t Series XVIII., Subseries 198. II Series XX., Subseries 211. t Subseiies 140. § Series XX., Subseries 208. VI Thus modified, the series corresponding with that entitled in the synopsis, ' Incubation o£ the ovum in birds,' now exhibits all the successive stages described by Mr. Hunter in his admirable account of the ' Progress and peculiarities of the chick*,' It seemed a sufficient reason for suppressing the twenty-Hrsi series of the ' Synopsis,-' that tlie preparations included therein exhibited stages of development nearly connected with those which preceding series were expressly established to demonstrate. The preparations illustrative of generation by artificial fission f have thus been re-united to those exhibiting the same effects by spontaneous fission J. The preparations exhibiting the 'changes of the tadpole into the frog § ' are now combined with the analogous and connected specimens constituting the group en- titled '■ Ova of animals which have gills when hatched, but afterwards lungs ||.' By thus combining the later with the earlier stages of development in the oviparous classes, the con- secutive phseuomena of such development in one series are brought under the immediate observation of the physiological student, and he is made familiar wdth the earlier stages of the formation of the vitellicle and allantois before he arrives at that series (the nineteenth in the synopsis) in which further changes of the allantois are exhibited, and its subserviency to the fornia- ation of the placenta is demonstrated. The preceding observations explain the plan of arrangement adopted in the present catalogue of the Hunterian physiological collection. The following remarks refer to the descriptive part of the same catalogue, and particidarize the sources of the julditional information that may be found in the present, when compared with the previously existing catalogues. The printed synopsis, already quoted, is limited to an expla- nation of the subjects of tlie several series and subseries of specimens. The catalogues descriptive of the individual speci- mens have hitlierto existed only in manuscript. * Iiitrotl. to the Fifth VoluniH, p. viii. + Series XXL, Subseries 210. % Series XA'II., Subseries 17l>. § Serie.s XXI., Sub.«evies 222. || Series XVIII., Subseries 194. The original documeuts explanatory of the physiological de- partment of the collection are the following : — First, A manuscript catalogue, in Mr. Hunter's handwriting, without date, but probably written soon after his return from Portugal in the year 1763. It briefly defines the nature of about two hundred specimens. In this catalogue the natural and morbid structures are grouped together in classes according to the organs ; there is then a short series of ' Monsters,' fol- lowed by specimens of natural history, under the heads of ' Beasts,' ' Lizards,' and ' Snakes.' The articles included in the two latter series were collected for the most part in Portugal, Spaiuj and Belleisle. This was the germ of the future Hunterian collection, and the foundation of its several departments, the pathological having been afterwards separated from the physio- logical preparations. It may not be uninteresting to record the first method of classification, in which the specimens are arranged according to the organs. It is as follows : — Class I. — ' Of the Brain, Medulla, and Nerves :' then follow, ' Heart and Vessels ; ' ' Larynx and (Esophagus ; ' ' Stomach,' 'Intestines,' 'Anus,' ' Liver," Gall-bladder," Spleen,' 'Kidneys,' ' Capsula renalis,' ' Parts of Generation,' ' Eyelids,' ' Eyes,' ' Ears,' ' Nose,' ' Tongues,' ' Skin,' ' Bones,' ' Epiploon,' ' Oils,' ' Ligaments.' The series of the ' Kidney ' includes, even at this early period, specimens of the injected tubuli uriniferi in the Monkey (' S. 6/ now No. 1235) ; in the Horse (' S. 9 and S. 10,' now Nos. 1209 and 1210) ; and in the Ass (' S. 12,' now No. 1208). The same series likewise displays the superficial arborescent veins in the kidney of the Lion and Leopard, and the reticulate arrangement of the same veins of the Seal, and it terminates with the con- glomerate kidney of the Porpoise. The series of the 'Nose' contains the preparation of the fifth pair of nerves in the nose, figured in the "Animal CEconomy, PI. XVIL and XVIIL," where it is described as having been made in the year 1754 *. The original number of this specimen in the old catalogue is ' c. 4,' it is now No. 1550 : it has thus been preserved eighty- * Animal CEconomy, 1792, p. 261. vin seven yt?tn's, and may be considered one of the oldest, ii' not the oldest Hnntevian preparation in the collection. The latest date which can be attached to any prejtaration in the present manu- script catjilogiie is 1764 ; the prepai'ation is tiie duodenum of a woman who died of a dysentery, and whose case is descrii)ed in •• Dissection 78, of Morbid Bodies, winter of 1 7iph iei mainly due to the same causes as those of the blood in the veins, with, in addition, the suction action of the venous Idood where that fluid rushes by the orifices by which the lymphatics o[)en into the veins. In some animals {e. : A combination of the two special struc- tures usually present, or a special arrangement to prevent the gills drymg. Examples. Crustacea : Eirgus latro. Gastroijoda : Ampullaria. Pisces : Ceratodus, Amia, &c. ^ Many fish habitually swallow air, which yields up its oxygen m exchange for the CO^ in the blood in the vessels of the ali- mentary canal, thus supplementing the respiration by gill. N. SOUND-PRODUCING ORGANS. (Including Larynx and Syrinx.) Used by animals for signalling their presence, to give warning of danger, and exciting sexual passion. Not Larynx or Syrinx. Examples. The simplest aud least-specialized in each class to commence the series. Crustacea. Arachnida. Myriapoda, Insecta. Reptilia. Mammalia. Larynx and Syrinx. Examples taxonomically arranged. xli o. URINARY ORGANS. (Including- Kidneys, Bladder, and Waste Products.) Chiei: duty the removal from the body oi: waste nitrogenous matter (as Urea and Urates) and surplus water. The cells that excrete this product are usually derived from those which line the body-cavity. Examples taxonomically arranged. They will sometimes include the reproductive organs. P. SPECIALIZATION AND DIVISION OF LABOUR AMONGST "PERSONS" OR "INDIVIDUALS." A mass of non-specialized protoplasm can perform all the essential functions of life ; it can move, take in food and digest it, grow by forming its own substance out of absorbed food which was originally unlike itself (a function peculiar to living matter), and can by division increase in number {e. g. Rhizopoda). In the Infusoria different layers of the protoplasm are specialized to perform particular functions. The higher forms of animals (Metazoa) are composed of numerous associated units (cells), each like the entire body of a Rhizopod, and of tissues specialized to perform one function, derived from such cells. We have here in the Metazoa a division of labour amongst the cells and tissues. In the following examples we find a further division of labour, certain semi-independent or independent " persons " produced by budding from the organism resulting from the development of one egg; or the dift'erent membei-s of a colony of "indi- viduals " take on the chief or exclusive performance of one function. This division of labour is of the same advantage to the members of a colony, as results from the special trades of civilized life. xlil Plants. Examples. Many commonly coiisiflered as organs. Animals. Examples, Hydiozoa. Anthozoa. Gestoidea. Individuals. Examples, lusecta ; Termes, &c. STRUCTURES CONCERNED IN THE PRE- SERVATION OF THE RACE. Q. REPRODUCTIVE SYSTEM. All animals are directly or indirectly dependent npon plants for their food ; and all plants and animals die from accident, disease, or natural decay. If they did not reproduce themselves all living organisms vpould become extinct. This is effected by the Reproductive System. Axexual. By budding, fission, spores. Plants. Examples fcaxonomically arranged. Animals. Eivamples taxonomically arranged. Sexual — Heriiuiphrod'ite. Plants. Examples. MonoBcious : Diclinous. xliii Animals. Examples taxonomically arranged. Sexual — Mule. Eivctinjiles taxonomically arranged. Sexual — Female. Examples taxonomically arranged. R. STRUCTURES FOR THE PROTECTION OF THE YOUNG. (Including Eggs, Egg-Capsules, Nests, &c.) Plants. Examples. Fruits. Animals. Examples taxonomically arranged. s. STRUCTURES CONCERNED IN THE NOURISH- MENT OF THE YOUNG. (Including Mammary Glands and Placentae.) Plants. Examples. Endosperm : Perisperm. Animals. Examples. Yelk. Mammary glands. Placenta;. Taxonomically arranged. xliv T. DEVELOPMENT. Plants. Examples. Germinating Seeds, &c. Animals. Examples taxonomically arranged. u. ALTERNATION OF GENERATION. DIMORPHISM. POLYMORPHISM. Plants. Animals. V. SECONDARY SEXUAL CHARACTERS. Characters whicb distinguisli tbe sex, iiiid that are not directly concerncd in reprodnction. Plants. I Animals J ^'^'^'"'P^^^ taxouoniically arranged. Sexual dimorphism. w. NORMAL VARIATIONS OF SPECIES. Livino- in tlio same locality. Examples taxonomically arranged. Living in different localities. Examples taxonomically arranged. X. ASSOCIATION OF DIFFERENT SPECIES, WITH OR WITHOUT MODIFICATIONS OF STRUCTURE. Commensalism. Association of two species, from whicli one (the guest) con- stantly found so associated derives advantage without injuring its host. Examples arranged according to taxonomic position of guest. Symbiosis. Association of two or more species for the advantage of all. Examples arranged according to taxonomic position of dominant form. Parasitism. Association of two species, of which one, the guest, derives advantage at the expense of the other, its host. Examples arranged according to taxonomic position of guest. CONTENTS. VOL. I. A. ENDOSKELETON. Nos. PLANTS 1—5 ANIMALS. PORIFEEA 6—12 HYDROZOA 13—14 ANTHOZOA. Chemical Composition 15 — 19 Stbuotube and Mode op Fobmatiost. Continuous, non-spicular "20 — 26 Consisting in part or entirely of separate sclerites (s23ictdes) 27 — 28 Modifications of the central supporting axis in the Qorgonacea. Containing coelenteric canals 29 — 31 Solid, and secreted by a layer of special ectodermic cells (caly ooblasts) . . . 32 — 41 ECITIXODERMATA 42—47 vni CONTISNTS OF VOL. T. ANNELIDA " BRACinoPODA 4,, CRUSTACEA oO— 53 ARACHNIDA 54_gQ [NSECTA 57 PELECYPODA a58-b58 Q-ASTROPODA 58 CEPHALOPODA 59— 59 c CEPHALOCHORDA 60 PISCES. Chemical Composition 61 63b STRucTimE 64 75 REPTILIA 76_76c AVES 77—87 MAMMALIA. Chemical Composition 88 96 Development and Gbowth. As shoivn hy Madder-staining 97 — 108 Groivth of the Antlers of Deer 109 — 133 In other hones 134 187 Bones containing G-as ob Am 188 — 203 CONTENTS OF VOL; I. xlix B. FLEXIBLE BONDS OF UNION AND SUPPORT.— VERTEBRAL COLUMN.— JOINTS. FLEXIBLE BONDS OF UNION AND SUPPORT. j^^^ AREOLAE TISSUE 1 SPECIAL ELASTIC STRUCTURES. Not bssbnttallt conneoteb with Skeleton . 2 — 5 CONTTECTED WITH VebTBBBAL CoLTJMN. Supraspinous 6 — 10 Interspinous 11 — 15 Subapiuous 16 — 20 Interarcual 21 CONNECTBr) WITH THE ElBS 22 CONNECTEB WITH THE LiMBS 23 — 24 JOINTS. "Without known function 25 — 29 Nodes — points of development of organs separated by internodes that eflfect the necessary elongation 30 — 33 That allow of continuous growth 34 — 37 That diminish the risk of fracture 38 — 45 That allow of voluntary motion. INVERTEBRATA 46—50 VERTEBRATA. Jaw 51 — 67 Vertebral Column. Acentrous 68 77 Ohordacentrous ArchceiitrouB gg jog Ribs 107—117 Shoulder-girdle 118—120 d CONTENTS OF VOL. 1. Noa, Shoulder 121 igg l^lbow 139—145 Wi'isb 146-149 Digits 150 Pelvic Girdle 151 Hip 152—170 Knee 171—182 Ankle 183—190 c. MUSCULAR AND ALLIED SYSTEMS. Nos. PLANTS 1—7 ANIMALS. INVERTEBRATA 8—63 VERTEBRATA. JFOKM AND TbXTUBB. Texture of Muscle 54 — 60 Texture of Teudon 61 — 66 Torms of Muscle 66—79 Eegional. Cutaneous 80—82 Head and Neck 83—94 Depressor maxillas inlerioris (Digastric) . . . 96 112 Trunk 113—121 Fore-limb 122—172 Hiud-lirab _ 173—246 DESCEIPTIVE CATALOGUE OF THE PHYSIOLOGICAL SERIES. STRUCTURES CONCERNED IN THE PRE- SERVATION OF THE INDIVIDUAL OR TO ITS ADVANTAGE A. ENDOSKELETON. (Including- all stractures that function as an Endoskeleton, whether derived from Ectoderm, Mesoderm, or Endoderm, or the ec[uivalent embryonic layers.) A structure specialized to give to the organism support, strength, rigidity, and protection to more deeply seated parts ; in some cases it furnishes the levers and fulcra for the move- ments of parts of the body or advantageous attachment for muscle. Its physical properties are independent of life. PLANTS. The bundles of thick-walled elongated cells commonly asso- ciated with the vascular bundles act as an endoskeleton. The cell-walls of the whole or greater part of a plant may bo hardened by lime (especially when exposed to violent waves, e. y. certain Algse = Corallines) or silex (as in grasses and horse-tails), so as to give the necessary strength and rigidity, These cannot be regarded as specialized endoskeletons, B 2 PHYSIOLOGICAL SERIES. A. 1. A Red Sea- weed {Delesseria sangainea). The perennial stem-like portion of the tballus has its cells crowded with reserve food-material in the form of aleurone grains. It gives origin in the spring to leaf-hke structures that die off in the autumn. Each has an axial bundle of somewhat elongated cells from which other bundles diverge and branch. They are thought to give some extra strength to this portion of the thallus, and serve as special paths for conduction of nutriment. The resemblance to the " veins " (vascular bundles) in true leaves is very great. Potter, J. Marine Biol. Assoc., vol. i. 1889, p. 171. A. 2. Transverse section of the stem of a Tree-fern {Ctjathea dregei). On the inner and outer side of each vascular bundle is a flattened bundle of almost black, greatly elongated (prosenchymatous), thick-walled cells derived from the fundamental tissue ( = tissue between epidermis on the outside and vascular bundles in the interior). The in- creased thickness of the walls of these cells is due to a Fig. 1. X 110, secondary deposit of lignone, which renders them hard and stiff. This form of tissue is known as " Sclerenchyma " ; it gives strength and stiffness to the stem. The drawing shows the structure of the sclerenchyma. (Fig. 1.) ENDOSKBLETON. — PLANTS. 3 A. 3. Sections of the stem of a Wax-palm {Copernicia cerifera), with a drawing illustrating its structure. On the phloem (usually outer) side of each vascular bundle is a bundle of thick-walled prosenchymatous cells of dark colour forming a sclerenchyma that gives strength and stiffness to the stem. In the flower-stem each vascular bundle is com- pletely surrounded by a sclerenchymatous sheath. Micheels, Mem. Cour. Acad. Belgique, t. liii. 1893, p. 1. Bot. Centralbl., vol. lix. p. 186. A. 4. Transverse section of the stem of Black Ebony {Diospyros melanoxylon). The outer portion of the wood (alburnum) is of a pale colour and is concerned in the conduction of sap. The central older " heart-wood " (duramen) is of a dark colour, and has ceased to conduct sap. It serves to give extra stiffness and strength to the stem. A. 5. Section of stem, portion of leaf, and drawings illustrating the structure of the sclerenchymatous spicular cells, and their arrangement in the leaf o£ Wehoitschia mirahilis. In Fig. 2. c. s. Arrangement of Spicular Cells in Leaf of Wehoitschia. Vert. long. sect. X 20. this plant, as in many others, certain cells of the funda- mental tissue ( = tissue between epidermis and vascular bundles) depart from the usual character of the funda- b2 4 PHYSIOLOGICAL SERIES, mental tissue, becoming greatly elongated and often branched. Their walls are thickened by a secondary deposit of lignone (CiaHigOj) on the inner side of the primitive cell-wall formed of cellulose (CigHzoOjo). Nume- rous crystals of calcium oxalate are imbedded in the outer surface of these cells. The spicular cells appear to confer some extra strength and stiffness to the parts in which they are present. They may also render the plant distasteful to animals ; and perhaps serve as a mode of disposal of redimdant carbohydrates. (Fig. 2.) Royal Gardens^ Kew. Hooker, Trans. Linn. Soc, vol. xxiv. 1864, p. 1. ANIMALS. POEIFERA. A, 6. A Calcareous Sponge {Grantia compressa) . Its soft parts are supported by definitely arranged calcareous spicules whose forms are shown in the drawing. Each spicule is formed in one of the cells of the mesoderm. In this sponge they consist of calcium carbonate, having the crystalline structure and other properties of calcite; the form, however, is organic. Presented hy Prof. C. Stewart. A. 7. A Siliceous Sponge {CranielJa [Tethyal cranium'), belong- ing to the Sub- Class Tetractinellida. The spicules do not fuse ; they are composed of colloid silica in layers around a delicate central cavity occupied by organic matter. The large spicules (megascleres) are mostly arranged in bundles radiating from the centre of the sponge and projecting slightly on its surface. Minute flesh-spicules (microscleres) are also present. Presented hy Prof. C. Stewart. A. 8. Half of a Siliceous Sponge {Corallistes noli-tangere. Sub- Class Tetractinellida). The soft tissues and loose spicules have been removed, leaving only the main skeleton. It consists of branched solid spicules (desma) that are ENDOSKELETON. — ANIMALS. 5 inseparably interlocked by short clubbed or mushroom- shaped processes at the ends of the branches. They are also held together by processes that firmly wrap around and grasp neighbouring spicules. The loose spicules (dichotrioenes) that support the dermal membrane, and those forming the main skeleton, are of large size (mega- scleres). The minute flesh-spicules (microscleres) are of two sorts, stellate or bistellate with blunt rays (chiasters or amphiasters), and style-shaped (styli), that is blunt at one end and pointed at the other. A drawing illustrates the forms of the spicules. Presented ly B. W. Priest, Esq. Sollas, Chall. Rep., vol. xxv. p. 339. A. 9. A Siliceous Sponge (Euplectella aspergillum. Sub-Class Hexactinellida). The siliceous spicules are six-rayed (hexactinellid). Those that form the main supporting framework are united by bars of silex (synapticulse) secreted by neighbouring cells. The magnified forms of some of the spicules that always remain free are shown in a drawing. Presented hy Prof, C. Stewart. A. 10. A Horny Sponge (Detidrilla rosea) with drawings illustrating the structure and mode of development of its fibres, they being secreted by investing cells known as sponginblasts ; the material they secrete as spongin. von Lendenfeld, Zeitschr. wiss. Zool., Bd. xxxviii. 1883, p. 285. A. 11. A Horny Sponge (Euspongia officinalis), with drawing, A. 12. A Horny Sponge {Dysidea fragilis), with drawing. Sand- grains coming in contact with the growing ends of the horny fibres adhere to them, and become invested by a thin layer of the same material. The amount of sand varies greatly with the locality ; this specimen was obtained off Hastings. Presented hy B. W. Priest, Esq. Schulze, Zeitschr. wiss. Zool., Bd. xxxii. 1879, p. 130. 6 PHYSIOLOGICAL SERIES. Htdrozoa. The supporting framework (corallum) of the following forms is secreted by the outer layer of the body (ectoderm) upon its external surface. It is accordingly outside the body, but since the latter remains closely investing and surrounding the corallum the coral functions as an internal support to the animal. The endoderm in many forms a cartilage-like support to the arms. The " supporting lamella " and mesogloea likewise serve for support. A. 13. Calcareous corallum of MUlepora alcicornis (Order Hydro- corallinse), and drawings illustrating its structure. The corallum is secreted by the outer layer of cells (ectoderm) of a network of tubes (hydrorhiza), and a continuous layer of such cells on the outer surface of the coral. The hydro- rhiza gives origin by budding to two sorts of zooids, which can be retracted into tubular chambers (calicles). The lower portion of the calicles are not occupied by the zooid, and are cut off by successively formed plates (tabulse). Only that portion of the Millepora superficial to the last- formed tabula is living. The interior of the hydrorhiza- tubes are filled with a symbiotic alga (^Zooxanthella infestans) in the form of small round yellow cells, having a well marked cell-wall : they are quite free. Moseley, Phil. Trans., vol. clxvi. 1877, p. 91. In the following diagrams the colours represent — Black or White = Corallum ; Brown = Ectoderm ; Blue = Mesoderm ; Green = Endoderm. A. 14. Calcareous corallum of Stylaster roseus (Order Hydro- coralliuse), and diagram showing its structure. The co- rallum is secreted as in the former specimen. The arrange- ment and shape of the calicles of the dactylozooids as a circle of flattened wedge-shaped chambers surrounding a central deeper and larger calicle in which the gastrozooid is lodged, gives this coral a close superficial resemblance to an Oculina (Class Anthozoa). A style-like process of the ENDOSKELETON. — ANIMALS. 7 coral at the base of the zooids simulates the cohimella of the Anthozoan. PI. I. fig. 1. Moseley, Phil. Trans., vol. clxix. 1879, p. 449. Anthozoa. Chemical Composition. The coral is in most cases composed of calcium carbonate associated with a varying amount of organic matter; minute traces of other salts are present. In some Gorgonacea (e.g. Gorgonia Jlahellum, G. setosd) calcium phosphate is the chief inorganic constituent of the axis, although none is found in the crust. A. 15. Horny axis of Antipathes politum. It has been ma- cerated in acid : this has caused a partial separation of its constituent lamellae. 0. C. 85 G. A. 16. Small portion of Organ-pipe Coral [Tubipora musica). It has been treated with dilute nitric acid which has removed all colour, and the calcium carbonate that alone renders the coral stiff" and hard. The polyps may be seen at the mouths of the tubes. 0. C. 84. Hunterian. A. 17. A similar specimen in which the tubes are somewhat larger and the polyps absent. 0. C. 85. Hunterian. A. 18. The axis of a main stem of a Coral [Melitodes ochraced). The lower portion has had its surface acted upon by dilute hydrochloric acid. This has partly removed the calcium carbonate, leaving the organic matter. In the "nodes" the organic matter is more abundant : they accordingly project above the level of the more eroded internodes, which are of a brioht red colour. Besides the calcium carbonate there is a small trace of calcium phosphate. 0. C. 85 A. A. 19. Smaller branches of the same Coral {Melitodes ochraced) similarly treated. 0.0. 85 b. 8 PHYSIOLOGICAL SERIES. Structure and Mode of Formation. Continuous, non-spicular. A, 20. Caryophyllia pi-ofunda, one in section and the other entire, as an example of a simple aporous Coral, with diagram. The sea-anenome-like polyp first secretes upon the rock to which it is attached a disc-like basal plate ; radiating ridges on the upper surface of this enlarge to constitute the septa, an extension of the outer ends of these grow together to form the theca, and an elevation in the centre is known as the columella. The corallum, although external to the polyp, functions as a deep-seated support, PI. I. fig. 2. G. V. Koch, Mitth. Zool. Stat. Naples, Bd. xii. 1897, p. 767. A. 21. A simple, free, aporous Coral {Fungia actiniformis), with diagram. It results from the detachment of the enlarged free end of a fixed coral resembling the preceding specimen. The septa are united by calcareous bars (sj'napticulse), which contribute to the strength of the coral. PI. II. fig. 1. Bourne, Q. J. Micr. Sci., vol. xxvii. 1887, p. 293. A. 22. A compound aporous Coral (^Pocillopora cespitosa), with diagram. The corallum is composed of tubes whose sides are in contact. The cup-like end of each tube lodges a polyp, the bottom of the cup is formed by a plate (tabula). The tabulse are formed whenever the cup becomes too deep from additions to its lip. The digestive cavities (coelentera) of the polyps communicate with one another by canals (cceleuteric canals). PI. II. fig. 2. A. 23. A fossil Coral (Favosites gothlandica). The tabulae are very distinct. Brit. Mus, A. 24, Blue Coral (ffeliopora cairulea, Order Alcyonaria), and diagram illustrating its structure. The corallum consists of tubules of two sizes. In the larger are lodged the polyps, each having eight pinnate tentacles ; the smaller lodge tubular extensions of the digestive cavity of the polyp PI. I. H Y D RO R H 1 Z A - ->^-A,!-,' CORALLUM DACTYL0200ID SASTROZOOID C.Stewart del. I.STYUASTER R03EUS. Bia^ranv of CoralLmiv ■with group of ZooicLs, Long, sect X 50. 2.CARY0 PH YLLI A PROFUNDA. Dcax^T-curo of CovcdJUiuny and/ Polyp, enlof'ffedy. \ C.Stewa,rfc del . l.FUNGIA ACTINIFORMIS. Dicu^T-ocmy of vert. sect. 2.POCI l-LOPORA CESPIT08A. DicLffrajYv of verb. sect, enlarged.- T t K r X 4 r Si 7. .tr PI. III. CORALLUIV; TABUL/E POLYP CALICLE TUBE 1 PI. IV. I.TUBIPORA MUSICA. Diciffi-cun. of vert .st>c{: . ctilctrgedy. 2.PARAGORGIA ARBOREA. Trufvs . sect. / 20,Spiciil^ X 15C . i I ( ! END OSK E LETON. — ANIMALS . 9 (ccfilenteric canals). The surface of tlie organism is alone living, the lower deserted portion of the tubes being cut off by tabulte. ?1. III. fig. 1. Presented by Dr. H. Woodward. Moseley, Phil. Trans., vol. clxvi. 1877, p. 91. A. 25. Perforate corallum of a Madrepore (Madrepora muricata). The corallum is permeated by a network of coelenteric canals, so that all except the oldest portions may be regarded as living. The ectodermic cells (calycoblasts) in contact with the external surface of the corallum effect its increase, but they more or less disappear from the deeper parts. PI. III. fig. 2. Fowler, Q. J. Micr. Sci., vol. xxvii. 1887, p. 1. Ogilvie, Phil. Trans., vol. clxxxvii. 1896, p. 83. A. 26. Horny corallum of Black Coral (Antipathes tdex). This material is tougher and less rigid than that of the preceding specimens. Skeleton consistmg in part or entirely of separate sclerites {spicules). Each spicule is formed in an ectodermic cell that has migrated into the mesogloea [firm jelly-like sithstance betioeen ectoderm and endoderm, formed by the ectoderm). A. 27. Spongodes florida, a colonial Alcyonarian. Some of the supporting spicules are shown, detached, by the side of a drawing of their microscopic appearance. A. 28. Two specimens, and diagram of the structure of an Organ- pipe Coral (^Tid)ipora musica, Order Alcyonaria). The tubes and platforms that unite them are formed by fused spicules, the spicules in the polyp-walls remaining separate. Coelen- teric'canals running in the platforms unite the polyps. A small inner tube is often formed as the result of the detach- ment and shrinkage of the soft tissues that line the outer large tube. PI. IV. fig. 1. Presented by Prof. C. Stewart. Hickson, Q. J. Micros. Sci., vol. xxiii. 1883, p. 558. 10 PHYSIOLOGICAL SERIES. The following specimens illustrate the modifications of the central supporting axis in the Gorgonacea (Axifera of Gray). The crust outside the axis always contains numerous spicules. KoUiker, Icones Histologicae, Zweite Abtheilung, 18G5. G. V. Koch, Morph. Jahrb., Bd. iv. 1878, p. 447. Axis containing coslenteric canals. A. 29. Small piece of Faragorgia arhorea, and two transverse sections. The axis is not well defined ; it consists mainly of firm mesogloea with some spicules, and is traversed by coelenteric canals. The spicules are most abundant near the surface of the axis, and in the mid spaces between the canals. The extended polyps may be seen on the surface of the specimen. The entire colony is branched mostly on one plane, and is often 1*5 or 1-8 metres in height, with diameter at base of 15 to 20 cm. Presented by Prof. C. Steicart. A. 30. Portions of Faragorgia arhorea, with diagram and draw- ings of its structure. PI. IV. fig. 2. Presented by Prof. C. Stewart. Axis formed by fused spicules and containing coelenteric canals. A. 31. Portions of Melitodes ochracea, and drawings of its struc- ture. The axis is jointed, consisting of short thickened nodes composed of loosely arranged spicules united to one another by their extremities ; the internodes are of a darker colour, containing more inorganic matter and with densely crowded and fused spicules. The spicules of the axis differ in form from those of the crust, but amongst them are occasionally found some of the crust-spicules that have been extruded from that structure. The axis is traversed by ccelenteric canals. PI. V. fig. 1. Presented by Prof. C. Stewart. Axis solid, and secreted by a layer of special ectodermic cells (calycohlasts^. A. 33. Suberogorgia suherosa, with drawings of its structure. The axis is composed of colourless spicules and horny A I I 1 Pl.V. C .Stew:a-rfc del . I . M ELITODES OCHRACEA. TrcLH^. lorty. se'±s X80 Spicules X 150. 2.SUBEROQORGIA SUBER03A. 3ect:XSU Spicule.^ / 130 . PI .VI. C.Stewaxt del . I CORALLIUM RUBRUM. Trccns . sect X 100 . Spicid.es / 150 . 2.CALIGOR61A VERTl C I ATA . Trctrts.sect./WC.GrcupofPch'jjs crt stern. r25 . Spa^u/^ nM i PI. VII . C.StewsLrt del. I.VERRUCEULA G U A DALU PE N S I S Tnarts.nect'.^IOO. SpCcxxIes 15C . 2. 1 S I S H I PPURIS . Tr cui^ . sect, cf caZo. inter-node' X 5C ■ Sp icules X /.W. Ml ENDOSKELETON. — ANIMALS. 11 matter disposed in ill-defined layers. The spicules differ from those of the crust, and are mostly fused in groups of two. PI. V. fig. 2. A. 33. Red Coral (Corallium riihrum). One piece is still in- vested by the crust, from the other the crust has been removed to show the axis, grooved on its surface for the ccelenteric canals of the crust, A drawing shows the structure of the axis, which is composed of layers of mixed calcium carbonate and organic matter ; in it are imbedded numerous spicules derived from the crust. PI. VI. fig. 1. Lacaze- Duthiers, Hist. Nat. du Corail, 1864, p. 102. A. 34. Caligorgia verticillata, with drawings of its structure. The axis consists of an intimate mixture of calcium carbo- nate and horny matter, disposed in well-defined wavy layers. PL VI."" fig. 2. A. 35. Verrucella guaclalupensis, with drawing of its structure. The axis closely resembles that of A. 34, but its layers are mostly parallel; occasionally spicules extruded from the crust have modified the arrangement of the layers. PI. VII. fig. 1. A. 36. Various portions of Isis Jiippuris, some in section, with drawing of its structure. The axis is jointed, consisting at first of short horny nodes alternating with long calcareous internodes. As the axis increases in thickness the horny matter is formed in excess of the calcareous, and may in places overlap and conceal it. In the oldest parts of the axis this sometimes is followed by an increased formation of the calcareous material forming a continuous layer on the surface. The ridges on the surface of the internodes are continued inwards on the surface by which they are attached to the nodes. The ectoderm-cells that secrete the calcareous internodes are large and granular, with indistinct nucleus. Those that secrete the horny nodes are about half the size of the former, clear, and with a distinct nucleus. PL VII. fig. 2. G. V. Koch, Morph. Jahrb., Bd. iv. 1878, p. 116. A. 37. Plexaurella crassa, with drawing of the structure of the axis and crust-spicules. The solid axis consists of horny 12 PHYSIOLOGICAL SERIES. material and wedge-shaped bars of calcareous matter in nearly equal proportion. The calcareous bars show on section a finely laminate structure with radial striation PI. VIII. fig. 1. A. 38. Eunicella verrucosa, and diagram of its structure. The axis is composed of horny matter disposed in layers. At the growing tips of the branches the central first-formed portion is spongy and contains much water. This foi-m of axis being elastic and strong is probably best fitted to resist ijiju'T) and is the type most prevalent amongst Gorgonacea. PI. VIII. fig. 2. Presented by Prof. C. Stewart. G. V. Koch, Morph. Jahrb., Bd. iv. 1878, p. 269. Alcyonarja that live with the lower end of the stem imbedded in mud or fine sand. Kolliker, Anat. Syst. Beschr. d. Alcyonarien, i. Pen- natuliden, 1872. A. 39. A Sea-pen (^Pennatula pliospliorea), laid open to expose the slender C3dindrical axis, which consists of an intimate mixture of calcium carbonate and organic matter. 0, C. 88. IIu7iterian. A. 40. A Sea-pen (^Pennatula grisea), laid open along the anterior aspect to expose the central axis. Large needle- shaped spicules are abundant in the pinnules. 0. C. 227. Uu7iterian. A. 41. A longitudinal section of Pennatula grisea, exhibiting the sti ucture of the central stem. 0. C. 228. Hunterian. ECHINODERMATA. A. 42. A Feather-star {Antedon 7'osacea). The endoskeleton is composed of a great number of small pieces formed in the connective tissue. They consist of a minute network of combined calcium carbonate and oi-ganic matter. The network usually first appears in the substance of inter- communicating cell-processes. The connective tissue of 1 PI .VIII AX IS C.SteT*aLrt dal. I.PUEXAURELUA CRASSA. T^wsdntLlc'tLg- Sects. X 100. 2.EUNICEI-UA VERRUCOSA. DLcLgrcatv of Pclyp cutcL ccoais X 4-0 Sect, of CLccLs and' criisb X 4X]0 . Spicules / 700 . ENDOSKELETON. — ANIMALS. 13 the visceral disc is stiffened by minute disc-shaped spicules often perforated in the centre. Presented hy Prof. C. Stewart. A. 43. Two half-grown specimens of a Sun-star (Solaster pap- posus). The viscera and upper (abactinal) body-walls have been removed from the lower specimen. The ambulacral plates including those of the oral system, the plates in the interradial septa (interbrachial pillars), and the stone-canal constitute the endoskeleton. From the upper specimen have been removed the whole of the body-walls excepting the adambulacral plates. Presented hy Prof. C. Stewart. A. 44. A Snake-armed Starfish (Ophiocoma erinaceus). The viscera and upper (abactinal) wall of the disc have been removed to show the ossicles about the mouth, and the vertebral ossicles ( = fused ambulacral plates) that are con- tinued from the arms into the disc. One arm has been detached with the six vertebral ossicles that were included in the disc. Some of the vertebral ossicles of the arm have been exposed by removing four of the dorsal (abactinal) shields. Three vertebral ossicles are shown in different positions, and below are enlarged models of these having on one side the surfaces giving attachment to the inter- vertebral muscles, painted red. A blue rod has been passed on one side into the opening by which the lateral branch of the radial water-vessel enters the ossicle, in the substance of which it forms a loop, and emerges in a cup-like de- pression to which the tube-foot is attached. The vertebral ossicles and oral skeleton form the endoskeleton. Presented hy Prof. C. Stewart. Ludwig, Zeitschr. wiss. Zool., Bd. xxxi. 1878, p. 347. A. 45. Echinometra lucunter. The shell (corona) has been cut in half, and the spines removed. The lower half shows five arch-like processes (auricula) that project into the interior and give attachment to certain of the jaw-muscles. The upper half shows the five genital organs (gonads) ; these, together with the intestine, mesentery, and other organs, are stifiened by numerous characteristic spicules that, like 14 PHYSIOLOGICAL SERIES. those of calcareous sponges, are optically as if carved from a crystal of calcite, but their forms are organic and often closely resemble siliceous spicules. Stewart, Trans. Linn. Soc, vol. xxv. 1866, p. 365. A. 46. Two halves of a Cake-urchin (Clypeaster humilis). Pro- cesses of the test arise from the under (actinal) and upper (abactinal) body-walls, the former being twice the length of the latter ; they meet and firmly articulate without fusion. They must greatly increase the strength of the test. There are also fine needle-like processes where the intestine is lodged, and five pairs of processes around the mouth (peristomal interambulacral apophyses). Presented by Prof. C. Stewart. A. 46 a. Test of a Cake-urchin {Clypeaster rotundus), the upper (abactinal) portion being removed, and the jaws (pyramids) left in situ. The strengthening wall-like columns are con- fined to the margin of the test. They are grouped into five interradial sets. In each set the walls bound a centi-al area that opens towards the vertical axis of the body, and has processes extending towards its interior. From the outer sides of the wall bounding the central area extend more strongly developed walls mostly parallel to the margin of the test ; these are separated from similar walls of neighbouring sets by about 3 mm. In this form the con- necting pillars and processes, the five processes (peristomal interambulacral apophyses) around the mouth, and the five jaws (pyramids) constitute the endoskeleton. A. 47. A Sea-cucumber (Jlolothuria nigra), laid open. The mouth is surrounded by a ring of ten calcareous plates, five radial to Avhich the longitudinal muscles of the body are attached, and five interradial. Presented by Prof. C. Steicart. Annelida. A. 48. A tube-dwelling worm {Spirographs spallanzanii), show- ing the branchial skeleton of the right side. The main portion of the skeleton consists of two tapering ribbons of ENDOSKELBTON. — ANIMALS. 15 cartilage, each forming an elongated spiral j they are joined to one another on the dorsal region of the worm by a narrow bridge. Long slender rods arising from the anterior edge of each scroll pass up the centre of the branchial filaments, and from these rods smaller skeletal cores enter the indi- vidual pinnules. The skeleton is composed of a variety of cartilage, consisting of large vacuolated cells whose walls are formed by a small amount of firm substance. Viallanes, Ann. Sci. Nat., ser. 6, t. xx. 1885, p. 1. Brachiopoda. A. 49. The dorsal and ventral valves of a Brachiopod {Magel- lania septigera). The shell consists of organic matter hardened by calcium carbonate and a considerable propor- tion of calcium phosphate. A complicated process (loop) springs from the dorsal valve close to the hinge ; it gives support to the " arms,'' and functions as an endoskeleton. Crustacea. A. 50. Endophragmal system of a Lobster {Homarus vulgaris). Infoldings (endopleurites) of the calcified cuticle project inwards from the sides of the body in the intervals between the segments. Each has a backward-directed process that divides the area corresponding with the limb into an in- ternal region lodging the protractor muscle, and an external for the retractor. One of the endopleurites has been painted light blue on its posterior face, the succeeding endopleurite dark blue on its anterior. Between the ventral plates (sterna) arise similar vertically directed bifid processes (endosternites), painted red ; they articulate with the endopleurites, and with one another in the mid line. The two articular surfaces for the limb are painted black. The sterna and their processes form a canal for the pro- tection of the ventral nerve-cord and artery^ and, with the endopleurites, give attachment to muscles. A. 51. Ventral portion of the antepenultimate segment of the cephalothorax of a Lobster {H. vulgaris). The endo- pleurites and endosternites have each been divided — 16 PHYSIOLOGICAL SERIES. their posterior halves heing loft in front of the segment, their anterior behind. On the left side the anterior half of the endopleurite is painted light blue, the posterior dark. The endosternites are similarly treated with red. A. 52. Entostevnite of Apus produdus. It is attached by muscles to the cuticle of the body-walls, and lies between the nervous system below and alimentary canal above. It has the structure of fibro-cartilage. The entosternite is thought to be represented in the Lobster by a small thin plate of connective tissue that lies immediately above the expanded inner ends of the first pair of endosternites. Presented hy H. M. Bernard, Esq. Ray Lankester, Q. J. Micr. Sci., vol. xxiv. 1884, p. 131. A. 53. Entosteruite of King Crab {Limulus polyphemus) . It has the same general structure and position as the former specimen. In chemical composition it consists of a chondrin-like body, and chitin (I'Ol Presented by M. F. Woodivard, Esq. Halliburton, Q. J. Micr. Sci., vol. xxv. 1885, p. 179. Arachnid A. A. 54. Entosternite of a Scorpion (Palamnceus spinifer). It has the usual minute structure and composition of that of other Arthropods. It consists of a stoutish body situated in the thorax between the alimentary canal and the nervous system, and of two " posterior flaps or wings that extend upv^■ards and backwards, having the position of a diaphragm situated at the junction of the cephalothorax and abdomen. Schimkewitsch, Zool. Jahrb., Bd. viii. 1895, p. 101. A. 55. Entosternite, together with the ventral plate (sternum) and proximal portions of the limbs of a Spider {7Jiei'a- phosa hlondii). The entosternite was loosely attached to the sternum by three pairs of slender processes. It gave attachment to numerous muscles. BNUOSKBLBTON.— ANIMALS. 17 A. 56. Portion of a Spider {Theraphosa hlondii), the carapace and soft parts have been removed to show the entosternite in situ. Inseota. A. 57. A section of the Hercules Beetle {JJynastes heroules), showing three dorsal and three ventral in-processes of the cuticle that give attachments to nmscles. Of the dorsal processes the most anterior = prophragma, springs from the anterior border of the mesothorax ; from the posterior border arises the larger mesophragma, the still larger metaphragma from the posterior border of the metathorax. These give attachment to the wing-muscles. Ventrally are the antifurca, medifurca, and postfurca that serve for the attachment of the muscles that move the legs. 0. C. 224. Hunterian. Kirby and Spence, Introd. to Entomology, iii. p. 581. Pblecypoda. A. a 58. Valves of Cucullcea concamerata. A process of the shell projects inwards, forwards, and downwards in the posterior region of either valve to give attachment to the posterior adductor. In the right valve the area of muscle attach- ment is painted red. A. l3 58. The valves of Pholas [Dadylina] dactylus. From the inner surface of the shell near the umbo there is a long slender process (falciform process) to the apex of which the anterior retractor pedis is attached. Gastkopoda. A. 58. The two pairs of buccal fibro-cartilages of an Ormer = Ear-shell {Baliotis tuherculata). In the upper specimen they are shown detached ; in the lower in situ from the left side. These cartilages lie beneath the floor of the mouth, giving support to the tooth-bearing lingual ribbon (radula), and attachments to the muscles that move it. Wegmann, Arch, de Zool. Exp., t. ii. 1884, p. 297. C PHYSIOLOfiTCAL SERIES. ('ephalopoda. A. 59. Tlio separate eurtila(i;es oi' a. Cuttlefisli {Scjna fdliouxi). The equatorial cartilage is peculiar in consisting of large cylindrical c(01s, mostly arranged in a single layer, and without ])rocesses ; its matrix is small in quantity and forms a definite layer around each cell. In the other cartilaoes the cells are small and more or less connected 1)V branched processes ; the matrix is very ahmidant and structin-cless. It contains 1*22 "/o of chitin. Boll, Arch. f.Mikr. Anat., Bd. v. supplement, 1869, \). U. Halliburton, Q. J. Micr. Sci., vol. xxv. 1885, p. 174. A. 59 a. A Cuttlefish {Sepia filliouxi) in which the natural position of the cartilages is shown by the entire removal of the soft parts on the left side. A. 59 b. A transverse section of the gill of a Cuttlefish (Sepia officinalis), comprising four gill-Iamell?e. The lamelho have been removed on the right to show a delicate rod of cartilage that stiffens the free border of the supporting membrane of each. A. 59 c. The cartilaginous skeleton of Nautilus pompilius. When in its natural position the cartilage lies close behind the buccal mass, sloping from above downwards and forwards. The upper horns with their processes support the central nervous system, the ventral flattened processes are embedded in the sides, and the median in the roof, of the funnel. In structure the cartilage corres])onds to that of Sepia. Oephalochokda. A. 60. The endoskeleton of AmpJdoxics lanceolatus. The skeleton comprises a notochord, buccal cartilages, and a dorsal and ventral row of fin-supports. The notochord extends from in front of the central nervous system to the tip of the tail, and consists of a soft core surrounded by a double sheath. The core is composed of a series of transversely striated plates (possibly the walls of extremely flattened chordal cells) arranged at right RNDOSKHLETON. — ANIMALS. 19 angles to its longitudinal axis : tliey are attached laterally to the internal notochordal sheath, but are separated from it, above and below, by a mass of branching cells (MuUer's tissue). The sheath consists of a thin elastica interna and a thicker outer fibrous layer. The buccal cartilages, situated along the ventral nnd lateral margins of the oral hood, are formed by the xm'um of a series of short segments. A process from the dorsiil end of each segment forms the cartilaginous support of a cirrus. These cartilages have essentially the same structure as the notochord. The supports of the dorsal and ventral fins are composed of a soft structureless material traversed by a few fine fibres. Each support is contained within an oblong lymph-space. Chorda, v. Ebner, SB. Ak. Wien, 13d. civ. 1895, p. 199. Buccal cartilages. Rolf, Morph. Jahrb., Bd. ii. 187(j, p. 101. Fin-supports. Pouchet, Q. J. Micr. Sci., vol. xx. 1880, p. 426. Fishes = Pisces. Chemical compositio7i. " Bone is a compound of animal substance aud calcareous earth, and serves to support the other parts of the machine, so as to allow of the different parts being kept at a certain distance from each other, and to be acted upon by the muscles or moving powers of the body. "These (the Bones) are of different shapes in almost every class of animals, varying as it is necessary for defence from external accidents, strength, velocity, or convenient attachment of muscles. " In some they are similar to shell, serving as a house for the animal, as in the turtle ; and in the more perfect animals they serve the same purpose for particular parts. " In quadrupeds, in some they are very ceUular, thin, and spongy ; in others, very hard, solid, and compact, according as atrength is required." — Hunterian MS. Catalogue. A. 61. The vomer of a Cod-fish {Gadm morrhua), which has been steeped in an acid, in order to remove the calcareoii 02 20 PHYSIOLOGICAL SERIES. onrth, and show the proportion of animal substance, which in this species is very considenible. 0. 0. 112. HunteHan, A. 62. Bone of the pectoral fin of a Cod-fish ( Gadus inorrhua), similarly treated. 0. C. 115. Hnnterian. A. 63. Some hones of a fish (JJelonel) from flxi South Seas, showing a oroen colour. 0. C. 219 C. JIunteriav. A. 63 a. Various Ijones of a Gar-fish {Belonc vuhjaris). The matrix of the bone is of a green colour due to Vivianite (ferrous phosphate). A. 631). Diagrams showing the proportion of the constituents of a Haddock's bone [Gadus ceglefinus). It will be seen that nearly 50 % of fresh bone is water, that calc. phosphate is nearly the sole inorganic constituent, and that about 18'5 7o is organic. The analysis was made by A. Gordon Salamon, Esq. Structure. A. 64. Cartilaginous skeleton of a freshwater Lamprey {Petro- myzon Jluviatilis). The axial rod (notochord), that extends nearly the whole length of the animal, consists of large vacuolated cells polygonal by mutual pressure, the matrix forming an extremely thin separating layer between the cells. In the other cartilages the cells are also polygonal from pressure, but the matrix is more abundant, forming a definite layer around each cell ; the combined thickness of the matrix between two cells being about a fourth of the diameter of a cell. A. 65. Transverse and longitudinal sections of the body of a Sea-Lamprey {Pelromyzon marinus), showing the relations of the notochord. It is surrounded by a double sheath composed of an inner fibrous layer that can be spHt info three sheets according to the course of the fibres, and a thin homogeneous outer layer (elastica externa). ^ The sheath is itself enveloped by a considerable quantity of dense skeletogenous tissue. V. Ebner, Zeitschr. wiss. Zool., Bd. Ixii. 1896, p. 469. liNDOSKBLETON. — ANIMALS. 21 A. 66. Anterior portion of the body of Bdellostoina cirrhatum. The soft parts have been removed from the left side to show the cartdaginous skeleton. A. 67. Piece of the jaw of a Shark. Near the surface of the cartilage is a layer of plates of calcified cartilage. Hunterian. A. 68. Two portions of the layer of plates of calcified cartilage, one showing the deep, the other their superficial surface, from a Shagreen Ray {Raja fuUonica). The plates are mostly hexagonal, and about 0'8 mm. in diameter. The outer surface of the plates is flat, the deep surface has strong ridees that radiate from the centre, and are in number equal to the sides of the plate and at right angles to them. A thin layer of uncalcified cartilage commonly invests the surftice. Leydig, Beitr. Anat. u. Entwickl. der Rochen u. Haie, 1852, p. 4. A. 69. Cartilaginous skeleton of a young Ray {Eaja macalata). A. 70. Skeleton of a Sterlet {Acvpenser rutlienus). It is largely composed of cartilage. The bone contains lacuna) with numerous canalicuh. The cranial bones forming pari of the exoskeleton have been removed from the left side. Klaatsch, Morph. Jahrb., Bd. xvi. 1890, p. 233. A. 70 a. Skeleton of Bony-Pike {Lepidosteus osseus), chiefly composed of bone. A. 71. Skeleton of a Haddock {Gadus cmylejinus), and drawing of the bone structure. The bones of Gadidas consist of matrix in which are spaces occupied by fluid, and various sized droplets of organic matter that stain readily by reagents. There are no blood-vessels or included cells. A. 72. Skeleton of a young Sword-fish {Xiphias gladias), with drawings of the microscopic structure of the bone. It consists of matrix disposed in concentric layers around the numerous blood-vessel-containing channels (Haversian canals.) There are no included cells, but from a few of 2^ PHYSIOLOGICAL SERIES. the caiuils minute tubes, like those of dentine, nidiate for a short distance into the matrix. Those tubes are most marked in Jlistiophorns. A. 73. Skeleton of a young Fistularia serraia, and skull of an adult. The bones in this fish, as also in all Pleuronectidaj (Flat-fishes), are traversed by numerous Haversian canals from which and from the surface of the bone numerous dentine-like tubules pass into the matrix. A drawing shows the structure. A. 74. Skeleton of Trout {Sahno fario) and Grayling {Tliyiiiallus vulgaris). As in all Salmonida.', cells lodged in lacunfc are present but are not provided with intercommunicating caualiculi. The structure is shown in a drawing. A. 75, Skeleton B-QWing {Clupea harengm) and Carp {Cy- ■prinus carp'io) . A dra wing shows the well-developed lacunic and caualiculi present in all (Jlupeidse and Cyprinidje. Reptiles = Reptilia. A. 76. The carapace of a very young Turtle {Chelone mydas), showing the state of ossification, which is continued from the margins of the ribs, at this period quite distinct from each other, into a pre-existing ossifiable basis of the costal plates, until these plates become joined by indented sutures similar to those of the cranium. 0. C. 131. Hunterian. Goette, Zeitschr. wiss. Zool., Bd. Ixvi. 1899, p. 407. A. 76 a. Longitudinal section of the left humerus of a Turtle {Chelone mydas). There are no epiphyses. The articular cartilage is 4 mm. thick, and has the normal milk-whit(; opacity : the cells are small and arranged in rows irregular in direction. At its deepest part the cells are mostly in rows parallel to the surface. Below this cartilage is a translucent layer 1 mm. thick ; the cells in it are rounded, larger than in the former, and arranged in vertical rows. Beneath this is a layer of similar thickness in which calci- fication of the matrix is taking place. There is much black pigment in the medulla, mostly following the course of the laJger blood-vessels. Preserved in 50 % glycerine. Presented by G. Rimj, Esq. I C.Stewart del BONE I . FisTULARi A vert.sect . X 100 . 2 SALMO .r,?^(7 4..CLUPEA . /J(5^. 3 THYMALUUS./J^^. 5 . CYPRI NUS . J! 300 9 ENDOSKELETON. — ANIMALS. A. 76 b. Loiigitudintil section ul' the lelt luuuerus ul' a Turtle (Clieloiw myda.s). There is no medullary cavity, its place being occupied by uniformly dense cancellous tissue. A. 76 c. Longitudinal section of the left humerus of a Crocodile (Crocodiltis anitus). A medullary cavity is present. Tlie cancellous tissue at the ends of the bone is dense and shows some tendency to a vertical disposition. Birds = Ayes. A. 77. The muscles and bones of the hind limb of a. ^ilk-fowl [Gallus ferrmjineus, var. morio), showing the peculiar dark brown colour of the periosteum. 0. C. 2057. Hunterian. A. 78. The right tarso-metatarsus of the domestic Fowl, longitudinally bisected, to show the results of the following experiment : — When the animal was young, the boue was perforated near each extremity, and a small leaden shot was introduced into each hole. After a certain period the animal was killed, and the length of the boue was found to have been increased to three inches and ten lines ; but the distance between the shots, which has now reached the medullary cavity, was exactly the same as when first intro- duced. [The original note of the experiment is preserved in the bottle.] » And here I must observe, that a bone does not grow m all its parts, that is, it does not grow by addition of neAV particles among those already arranged, or in their interstices, but by the addition of parts lengthways or sideways of the bone. This I proved by exposing the bones of young animals, and boring holes in them, which were prevented from being obhterated by fixhig pieces of leaden shot in them ; these hones were examined a con- siderable time after, when, although the bones had considerably grown, the holes were exactly at the same distance from each other."— Jb/m Hunter, MS. Lectures. 0 C 189 llunterian, A. 79. The left tarso-metatarsus of the domestic Fowl, upon which the following experiment was performed : — Two small holes were made by cauterization near the ex- tremities of the bone ; the length of the bone at that time being 24 PHYSIOLOGICAL SERIES. two inches and ton linos, and the distance between the holes one inch and eight lines. After a certain period the animal was killed, and the length of the bone was found to be three inches seven lines, while the space between the apertures was one inch and eleven lines ; the increase of the bone beyond the points of cauterization being more than double that of the space included between them. [The original note of the experiment is preserved in the bottle.] ^- ^- 188. Hvnlenan. A. 80. The sternuin, sternal ribs, and scapular arch of a young Condor {Sai'corhamjjhus gryphus) ; the sternum with its well-developed keel is formed by one continuous cartilage. Ossification has commenced in the coracoids and scapulae 0. C. 133 E. A. 81. The sternum of a Black Swan {Cygnm atratus) 83 days old. 0. 0. 133 B h. A. 82. The sternum of a Black Swan {Cijgnus atratus) 153 days old. 0. 0. 133 EC. A. 83. A longitudinal section of the ulna of an Owl. The air- cells are not continued into it, its cavity having been filled with medulla. 0. C. 211. Hunterian. A. 84. A longitudinal section of the femur of an Owl, which has also had no connection with the air-colls, but contains medullary matter, and exhibits the difference between such bones and those which contain air. 0. 0. 212. Hunterian, A. 85. A longitudinal section of the lower part and articular end of the tibio-tursus of a young Ostrich, with the vessels of the periosteum injected. O.C. 119 A. A. 86. A section of the upper extremity of the tibio-tarsus of a young Ostrich, showing the more compact cellular struc- ture, containing medullary matter ; and the epiphysis. 0. C. 218. Hunterian. A. 87. A section of the lower extremity of the tibio-tarsus of a young Ostrich, showing th(( compact cancellous structure, and the medullary cavity. 0. C. 219. Huntcriun. ENDOSKELETON. — ANIMALS. 25 Mammals = Mammalia. Chemical com^wsiiion. A. 88. A small portion of fossil bone deprived of its earth. 0. C. 120. Tlunterian. A. 89. A larger portion of fossil bone, prepared in a similar manner. 0. C. 121. JJunterian. A. 90. A portion of fossil bone from an animal belonging lo the genus Bos, pre];)ared in a similar way. 0. (J. 122. Hunterimi. A. 91. The animal part of a portion of a Deer's horn {CervuH giganteus), from Ireland, in a fossil state. 0. C. 123. Messrs. Apjohu and Stokes foimd the animal basis to constitute ■lS-87 per cent, of the weight of the bones of the Megaceros : and the following proportions of the earthy constituents : — • Phosphate of lime and magnesia. . 43'45 Carbonate of lime })'14 Ferric-oxide 1-02 Silex 1-14 Hunterian, A. 92. The animal part of some small portions of the cranium of the Ursus spelctus or Boar of the Caverns, from Bayreuth in Germany. 0. (J. 124. Hunterian. Hunter, Phil. Trans., vol. Ixxxiv. 1794, p. 415. A. 93. A section of the tympanic bone of a Whalebone 'Whale {Baluiiia mysticetus), which has been subjected to the action of an acid, and deprived of its earthy constituent. It exhibits a concentric laminated structure and uniform solidity ; the firat-formed central part not having undergone any change from the action of the acid, and no part ex- hibiting a trace of fibres, cancelli, or vessels. 0. C. 202. Hunterian, A. 94. Another section of the same bone, similarly treated, and exhibiting more distinctly the laminated texture. 0. 203. " The bony part of the organ (of hearing) is very hard and 26 PHYSIOLOGICAL SERIES. bliltlu, leiidcriiig it even ditticull tu Ijc cut with a saw, without its chipping into pieces. That part which contains the immediate organ is by much the liardest, and has a verj' small portion of animal substance in it ; for when steeped in an acid, what remains is very soft, almost like a jelly, and laminated. The bone is not only harder in its substance, but there is on the whole more solid bone than in the corresponding parts of quadrupeds, it being thick and massy." — John IJunte>\ On the Structure aud (Economy of Whales, Phil. Trans. 1787, Ixxvii. p. 432. Hunteinan. A. 95. A section of the tympanic bone of a Whalebone Whale [Balcena mi/ sticet us) , Bumlarly treated. 0. C. 116. Ilunteiian. A. 96. A portion of the soHd part of a Human femur, which has been steeped in an acid, dried, and preserved in oil of turpentine, to show the animal part. 0. C. 117. JIunlerian. Development and Growth. The following preparations are from the common Hog {Sus scrofa), and are the results of experiments made by feeding that animal on the root of madder [Ruhia tindorum), but they have now lost their colour. A. 97. The skull of a young Pig, slightly tinged. 0. (/. 190. Hunterian. A. 98. A larger skull, more strongly coloured. 0. Vj. 1111. Hanterian. A. 99. The right side of the lower jaw, in which the dentine of the teeth has retained more j)erfectly the red colour, whilst the enamel is of its ordinary whiteness ; [a circumst;mco which was remarked by Mr. Belchier, the discoverer of this property of madder. — Fhilo.t. Trans. 1736, xxxix. p. 287.] O.C. iy2. Himterian. A. 100. A longitiulinal section of the humerus. The madder appears to have been remitted a short tinie before death, as there is a thin layer of uncoloured bone deposited on the external surface. 0. C. 193. Hunterian. ENDOSKELETON. — ANIMALS. 27 A. 101. A lonoitudiniil section of the ulna, i)robably from the same animal as the precedino;. 0. C 194. Ilimterian. A. 102. A longitudinal section of ii metacarpal bone, in which an external layer of uiicoloured bone may be observed, as in A. 100, being probably part of the same animal. 0. 0. 195. Hunterian. A. 103. The os innominatum, in which a very slight tinge remains. 0. C. 196. llunterian. A. 104. A longitudinal section of the femur of the same Hog as A. 100. In this preparation may be observed a very thin layer of uucoloured bone deposited on the exterior of the shaft after the madder was remitted, and also some of the original uncoloured bone which had not been absorbed from the interior of the shaft when the animal was killed. 0. C. 197. Hunterian. A. 105. A longitudinal section of the femur of an older Hog, in which the layers of bone deposited before, during, and after the administration of madder are more distinctly observable. 0. C. 198. [This preparation is figured iu au original drawing by Wm. Bell, Mr. Hunter's Assistant.] Hunterian. A. 106. A longitudinal section of the femur of an older Hog, in which the coloured bone, deposited while the animal was imder the influence of the madder, may be observed in some places to have reached the medullary cavity ; the whole of the originally exterior uncoloured bone having been entirely absorbed at those parts. 0. G. 199. Hunterian. A. 107. A longitudinal section of the tibia of the same Hog as A. 100. It exhibits the same circumstances as are described in A. 100 and A. 104. 0. C. 200. Unntei-ian. 28 rHYSlOLOGlCAL SERIES. A. 108. A longitudinal section of the tibia of a younger Hog, with a thin exterior layer of coloured bone. 0. 0. 201. By comparing this specimen with, and observing the size of the medullary cavity in, the preceding, the extent of the absorbing process will appear manifest; since the cavity is rendered suffi- ciently large to contain the entire bone of the earlier period of growth. " In the formation of a bone, ossification begins in a spot, and gradually increases. By feeding an animal on madder, it is shown, that while bony matter is deposited on the outside of the bone, the absorbents are removing it from the inner side, otherwise the bone would become heavy and clumsy, and unfit for motion ; therefore as the bony mutter which was deposited becomes useless, nature removes it by the absorbents." — John Hunter, MS. Lectures. See also " Experiments and Observations on the Growth of Bone, from the Papers of the late Mr. Hunter, by Everard Home, lilsq., r.ll.S.," in the Transactions of a Society for the Imjn'ovement of Medical and Ghirurgical Knoivled(/e, vol. ii. p. 277. Read Oct. 4, 1798. The colouring-matter of madder has a great affinity to phosphate of lime, which, if artificially precipitated from a solution coloured with madder, carries down with it the colouring-matter in a state of combination which water does not disturb. The colouring prin- ciple of madder is very slightlj' soluble in water, but is abundantly so in albuminous fluid ; and consequently is readily carried along with the circulating blood dissolved in the serum, and is deposited, combined with the phosphate of lime, wherever this salt is sepa- rated from the blood to contribute to the increase of reparation of bone. We may accordingly draw an inference as to the part of a growing bone which receives the accessions of osseous substance by observing the deposition of the madder-stained phosphate of lime. Ilimterian. For Illation of Bone, exemplifed in the Groioth of the Antlers of Deer. All the exani})le.s are from the Fallow Deer {Cervus dama). A. 109. A transverse section of part of the palm of the antler, while in a growing state, injected. 0. (J. 163. The parts which invest the antler at this period are, a vascular membrane similar to periosteum and continued from the peri- ENDOSKBLBTON . — ANIMALS . 29 cranium, cutis and cuticle continued from the integuments of the head, and a particular kind of short downy hair, which S'ives it a velvety appearance. Himterian, A. 110. The extremity of the palm of the antler, while in a growing state, injected. 0. C. 164. Hunterian. A. 111. A transverse section of part of the palm of the antler, while in a growing- state, injected, from which the outer velvet-like integument has been removed, to show the vascular periosteal membrane, part of which is turned back. 0. 0. 16.5. Hunterian. A. 112. A transverse section of })art of the palm of the antler, wliile in a growing state, injected, to show its delicate can- cellated structure, its vascularity at this period, and its periosteum, part of which is reflected from the bony substance. 0. C. 166. Hunterian. A. 113. A horizontal section of part of the palm of the antler, while in a gi'owing state, injected, and showing the same circumstances as the preceding preparation. 0. C. 167. Hunterian, A. 114. The outer layer of bone and the periosteal covering of part of the palm, and of one of the branches of the growing antler, highly injected, and deprived of the earthy material by being steeped in acid, so that the ramifications of the vessels in the substance of the bone are more clearly shown. One of the external vessels of the periosteum derived from branches of the external carotid is also exposed. 0. C. 168. " We find it a common principle in the animal machine, that every part increases in some degree according to the action required. Thus we find muscles increase in size when much exercised ; vessels become larger in proportion to the necessity of supply, as for instance in the gravid uterus ; the external carotids in the stag, also, when his horns are growing, are much larger than at any other time : and I have observed that in inflammation the vessels become larger, more blood passes, and there appear to be more actions taking place; but the nerves do not seem to 30 PHYSIOLOGICAL .SERIES. undergo any change. The nerves of the gravid uterus are the same as when it is in the natural state ; neither do the branches of the fifth and seventh pair of nerves in the stag become larger." —Himiei; On the Blood, 4to, 1704, p. 288. Hunteriav. A. 115. A section of part of the palm of the antler, injected, stripped of its periosteum, and steeped in an acid, to show the liioli degree of vascularity in the substance of the bone at this period of its growth. 0. (). 161). JIunteinan. A. 116. The other section, or counterpart, of the preceding specimen. 0. 0. 170. Ifunterian, A. 117. A small portion of the palm taken from the same antler as the preceding specimen, and prepared in the same manner. It is extremely vascular. 0. C. 171. Huntenan. The following seven preparations have been minutely injected, steeped in an acid, dried, and preserved in oil of turpentine, to show the vascularity of the substance of the growing antler. A. 118. A longitudinal section of an antler, in which the longitudinal disposition of the fibres may be observed. 0. C. 172. Huntenan. A. 119. A similar specimen. 0. 0. 173. Hunterian. A. 120. A similar specimen. 0. C. 174. Hunterian. A. 121. A transverse section of the palm of the antler, which gives to the internal structure a reticular appearance, in which part it may also be observed, that the blood-vessels are exceedingly minute, there being no large branches as on the external surface. See No. A. 114. 0. C. 175. Hunterian. A. 122. A similar specimen. 0. 176. Hunterian. A. 123. A small portion of the cancellated structure of the palm, cut in the direction of the fibres. 0. C. 177. Hunterian, ElsDOSKELETOK. — ANIMALS. 31 A 124. A section of the outer compact substance of the palm. 0 C 178 Hvnterimi. A. 125. A section of part of the os frontis and of the base; of a Deer's antler, of which the growth was nearly completed. O.C. 179. It shows the antler to be a continuation of bone from the outer table of the skull, and the velvet-like covering of the antler to bo equally continuous with the integuments of the head. It shows also the burr or pearl which has been formed round the base of the antler preparatory to the separation of the vascular integument of the antler from that of the skull. In the formation of the burr, wbich is the last part of the process, and takes place rapidly, the osseous tubercles of which it is composed are projected outwards, and, by their pressure, induce absorption of the vascular external covering at that part. The cessation of the vascular action, or arrest of the unusual deter- mination of blood to the antlers, is due to the same kind of constitutional and seasonal cause or influence as that w^hich excited it : and, as the vessels diminish, the ossification of the burr en- croaches upon their diminishing area ; hut it is not the mechanical cause of that diminution. The chief final purpose of the burr appears to be to defend the margin of the cranial integuments around the base of the antler. When the circulation through the carotids has returned to its normal stale, the whole of that once very vascular and sensible tegument loses its vitality, dries, shrinks, and peels oflP, leaving the antler a naked insensible wea.pon. In one of the branches (the brow antler) in this preparation, the whole of the vessels appear to have been thus obliterated : in the other a slight degree of vascularity remains, and one of the large external arterial branches is still uncompressed. ° Himterian. A. 126. A section of part of the os frontis and base of the antler, which has been completely formed and divested of its external tegument, or 'burnished,' as it is technically termed. This specimen has been injected, and steeped in an acid. 0. C. 180. Hnnienan. A. 127. A section of part of the os frontis and base of the antlei-, injected and steeped in an acid, to show tlu^ connection of 32 PHYSIOLOGICAL SERIES. the horn with the skull, the loose spongy texture in the centre of the bono, and tho" outer, compact, last-formed layer. 0. C. 181. Iluntenan. A. 128. A slice of the same parts as the preceding preparation, showing the same circumstances. 0. C. 182. ffunterian. A. 129. A transverse section of the beam of the same antler as A. 127, injected and steeped in acid, " showing the two stages of growth, and its becoming cellular in the centre." [This is the original description in the manuscript Cata- logue; but Mr. Hunter, unfortunately, has not left any commentary or further explanation of his ideas respecting this specimen.] O.C.I 83. Ilvnterian, A. 130. A similar preparation. 0. C. 184. Hunterlan. A. 131. A similar preparation. 0. 0. 185. Hunterian, A. 132. A section of part of the skull and base of the antler, a short time previous to its being shed ; injected and steeped in an acid. It shows the commencement of the interstitial absorption at the root of the antler, which renders that part soft and yielding ; and also the separation of the outer, last-formed, compact layer of bone from the internal spongy part. 0. C. 186. Hunterian. A. 133. A slice of the same parts as the preceding preparation, which exhibits more clearly the progress of the interstitial absorption at the base of the antler. 0. C. 187. Hunterian. Development of other- Bones. A. 134. The cranium of a Human Foetus (at about six months), showing the several places of commencement or centres of ossification, and the ossific matter deposited in fine bony fibres radiating therefrom. 0. C. 132. Hunterian. A. 136. The parietal bone of a Human Foetus, showing its vascularity and the radiation of the osseous fibres from the centre. 0. C. 162 a, Mus. Sir Astley Cooper, Bart, ENDOSKBLETON. — ANIMALS. A. 136. One halt' of the frontal bone of a Human Foetus, finely injectecl, and preserved in alcohol, showing its vascularity. 0." C. 162 B. Mns. Sh Astley Cooper, Bart. A. 137. The vertebral column of a Human Foetus of the sixth month, injected, showing the commencement of ossification in the bodies and arches of the vertebrso. 0. 0. 132 A. The parts of the arches which are ossified are the two vertebral laminte or " iieurapophyses." Ossification usually commences in the Iieurapophyses before it does in the centrum, viz. about the sixth or eighth week, by a single centre in each. The neura- pophyses unite together first at the base of the spinous process, completing the arch in the first year after birth : in the course of the third year, the bases of the ueurapophyses, which have ex- tended into the centrum so as to form its neural angles, imite with the independently ossified part of the centrum. Prior to puberty, the following epiphyses exist, one flat plate forming each articular end of the centrum— a terminal epiphysis for the spine, another for the diapophysis, and a third for the metapophysis, where that process exists. With regard to the atlas, the ueurapophyses begin to be ossified as early as in the other vertebrae, but the so-called body does not begin to ossify until after birth. The ueurapophyses unite together between the second and third years, and with the hypa- pophysis between the fifth and sixth years ; the true body of the atlas, called " odontoid process," begins to be ossified about the same time as the body of the dentata, viz. about the sixth month of foetal life, but by two centres placed side by side, which unite together before birth. The proper centrum of the axis coalesces with that of the atlas about the fourth year. The pleurapophysis of the seventh cervical is formed from a separate osseous nucleus, at about the sixth month, which usually unites at one end mth the centrum, at the other end with the diapophysis, about the fifth or sixth year. The transverse processes of the first lumbar vertebra are some- times developed from a separate centre, when they are " pleura- pophyses " as long as they remain distinct : those of the other vertebra) are exogenously developed, and are " diapophyscs." As the iileurapophysial element homologically enters into the formation of the hole in the transverse process of the cervical vertebrae, but is autogenously developed only in the seventh, the pleurapophysis D 34 PHYKIOLOOTCAL SEBIES. becomes thus occasionally exopjcTious in the nccli, as the neiirn- pophysis does in the tail. In the sacrum, besides the osseous nucleus for the centrum, and for each neurapophysis, one for each pleurapophysis commences about the sixth month close to the fore part of each nervous inter- space, in the three anterior vertcbrjc ; the lowest appearing last, about the ninth month : the junction of the neurapophyses to form the arch begins in the lowest vertebra first, viz. about the second year, but the first sacral vertebra is not a single piece before the fifth or sixth year. About the sixteenth year the sacral vertebra) begin to coalesce, and the fourth and fifth are usually united by the eighteenth year, the process of union gradually proceeding upwards : the terminal epiphyses of the sacral centrum are formed as in the true vertebrsB ; and lateral epiphyses, also, begin to form, one for the ends of the pleurapophyses of the first two vertebrae, and one for those of the last three. The whole sacrum is not consolidated till about the thirtieth year. Each coccygeal vertebra is ossified from a single centre. Presented hy William Lawrence, Ksq. A. 138. The vertebral column of a mature Human Foetus. The ligamentum commune anterius has been removed, to show the intervertebral substances, which are composed largely of concentric ligamentous fibres, passing between and con- necting the whole of the articular surfaces of the bodies of the vertebrae, as is exhibited in the preceding specimen. The articular processes are connected by another mode of arti- culation, where opposed cartilaginous articular surfaces are simply in contact, being connected to each other by a capsular hgament and synovial membrane. The pleurapophysis has been preserved on the left side of the seventh cervical vertebra. The summits of the neura- pophyses are joined by cartilaginous rudiments of the neural spine. Short cartilaginous pleurapophyses extend from the diapophyses of the lumbar vertebrae. They have begun to be ossified in the first three sacral vertebrfe. 0. C. 247. Hunterian. A. 139. The sternum of a Human Foetus of the sixth month, exhibiting the commencement of ossification by four separate points or centres ; that of the manubrium, or first bone, ENDOSKELETON. — ANIMALS. 85 has been removed from the cavity in which it was imbedded. 0. C. 132 B. Miis. Ileaviside, No. 90. A. 140. Tlio sternum and sternal ribs of a Human Foetus of the sixth month, injected, dried, and preserved in oil of tur- ])entine. Fonr centres of ossification are established in the sternmn, representing the ventral spines of the first four thoracic segments of the skeleton. 0. 0. 182 c. Mus. Sir Astley Cooper, Bari. A. 141. The sternum and sternal extremities of the true ribs of a mature Human Foetus. Four separate points of ossification may be observed in the sternum. 0. C. 133. Hvnterian. A. 142. The sternum of a Child at an early period of life, showing vessels from the internal mammary arteries, ramifying on the several separate ossifications. O.C. 134. Hunterian. A. 143. The left humerus, of .a new-born Leopard {Felis pardus), showing the cartilaginous epiphyses: the lower one is extended over the division of the inner condyle, and closes there the fissure through which the brachial artery and median nerve pass ; which fissure, by subsequent ossification and confluence of the distal epiphyses, is con. verted into a foramen. 0. G. 133 F. A. 144. A section of the proximal extremity of the humerus of a young person, showing the reticular cancellous structure of the epiphysis, and of the extremity of the diaphysis of the bone. 0. C. 204. Hunterian. A. 145. The counterpart of the preceding preparation. 0. C. 205. Hunterian. A. 146. Longitudinal sections of the extremities of a Human humerus, radius, and ulna, from a subject aged 15 years. 0. C. 205 A. Presented by A. H. Tubby, Esq. A. 147. A. section of the epiphysis of a metacarpal bone of a ( 'alf, showing ossification beginning in several parts of the cartilage. 0, C. 139. Hunterian. d2 36 PHYSIOLOGICAL SERIES. A. 148. A similar preparation. 0. 140. Ihtntman. A. 149. Another section, to show further progress of the ossifi- cation. 0. C. 141. Ihmterian. ^- 150. A section of the epiphysis of the shank-bone of a Calf, in which ossification is chiefly advancing from the centre. 0. C. 142. Hunterian . A. 151. A section of the epiphysis of a metacarpal bone of the same animal, injected : with a more distinct centre ol* ossification. 0. 0. 143. Ihmterian. A. 152. Another section, with the ossification more advanced. 0. C. 144. Ifunterian, A. 153. The cartilage of an epiphysis, with the central ossification well-injected, showing that it is jniich more vascular than the surrounding cartilage. O. C. 145. Ilimterian. A. 154. A similar preparation. 0. 0. 146. Hunterian. A. 166. A similar preparation, with the ossification in its centre more advanced. 0. 0. 147. Hunterian. A. 156. A section of temporary cartilage. The large vessel which traverses the preparation probably lies in the inter- space of two adjoining epiphyses, 0. 0. 148. Hunterian. The following preparations have been injected, steeped in an acid, dried, and preserved in oil of turpentine, to show the A'ascularity of growing bone. " Parts whose use in tlie machine may be said to be passive, as tendon, cellular membrane, ligaments, investing membrane, bone, and cartilage, which last is probably the most passive, have all small vessels, and of course but few that are visible. As bone, how3ver, is composed of two parts, viz, animal substance and earth, it is probable that there may be more action required to form the latter than either tendon or cartilage, and therefore there will be more vessels. " As a further proof that this is a general principle, we find that ENDOSKKLKTON. — ANIMALS. 37 all growiug parts are much more vascular than those that are come to their full growth ; because growth is an operation beyond the simple support of the part : and this is the reason why young animals arc more vascular than those that are full-grown."— " This is known by injections, when parts are in the growing state, or are just grown, and for some time utter:'— Himter, On the Blood, 4to, 1794, p. 156. A. 167. A traiisvei-se section of the epiphysis of a cylindrical bone, which exhibits the progress of the vessels from the circumference towards the centre. 0. C. 149. Hunterian. A. 158. A section of the metacarpal bone of a Calf. 0. C. 152. Hunterian, A. 159. A similar section of the metacarpal bone of a Calf. 0 Vi 153. Hunterian. A. 160. A vertical and longitudinal section of one of the toes, finely injected, of a foetal Calf {Bos taicrus). It shows the large cartilaginous epiphysis of the metacarpal bone, and the highly vascular ossific centres of the three phalanges. The sesamoid is cartilaginous. 0. G. 133 H. AIus. Sir Astley Cooper, Bart, A. 161. The pelvis of a (female) mature Human Foetus, showing the radiating disposition of the ossific fibres in the ilium, and the separate points of ossification in the ischium and pubes, and in the bodies and neurapophyses of the sacral vertebra. The coccyx is still wholly cartilaginous. 0. C. 133 A. Presented by W. H. Clift, Esq. A. 162. The right femur of a foetal Leopard, showing the carti- laginous epiphysis of the head, the great trochanter, and the condyles. O.C. 133g. A. 163. The femur of a mature Human Foetus, showing the cartilaginous epiphyses ; the superior of which compre- hends the great and little trochanter. 0. C. 133 B. Presented by W. H. Clift, Esq, 38^ PHYSIOLOGICAL SETllKS. A. 164. A .small section of bone, while in a growing state ; apparently the outer crust of a tibia of a Sue scroj'a. 0. C. 158. Huntenan. A. 166. A similar preparation. 0. C. 159. lluidenan. A. 166. A transverse section of an ej)ipliysis [i)roljably from the leg of a foetal Calf {Bos taurt(s)^, the ossification of which is nearly completed. 0. (J. 150. Huntenan. A. 167. A similar pre[)aration. 0. (_!. 151. Ilunteria/i. A. 168. A longitudinal section of the tibia of a Oalf. 0. C. 160. Ilinitenait. A. 169. The tibia of a mature Human Foetus, showing the carti- laginous epiphyses. 0. C. 133 c. Presented by W. U. Cli/t, Esq. A. 170. A transverse section of the tibia of a young Man, exhibiting its degree of vascularity. 0. 0. 1(31. Hunterian. A. 171. A section of the lower part of a Human tibia, in which the degrees of vascularity of the epiphysis, the cancellous extremity, and denser part of the shaft of the bone may be compared with each other. 0. C 162. Huntenan. A. 172. A section of the diaphysis of a Human tibia, injected; ex[)osing the medullary cavity, and the vessel of the marrow (Arteria medullaris), ramifying on the lining membrane of the cavity. 0. C. 209 A. Presented hy William Lawrence, Esij. A. 173. Sections of the extremities of right femur, tibia, and fibula, from a subject aged 15 years. Presented hy A. H. Tubby, Esq. A. 174. The upper extremity of the tibia of a Child, having the patella attached. The arteries of the cartilaginous ENDO&KBLETON. — 2VNIMALS. " 39 patella are injected, but ossilication had -not yet begun. 0 G 135. Huriterian. A. 176. Tlie patella of a Child more advanced in age, in which ossitication has begun in the centre, and has extended along the coats ol: the arteries, making them appear like boiiy ramifications. 0. C. 130. Huntevian. A. 176. A series of three Human patellte of different periods of growth, to show the progress of ossification. 0. 0. 137. Huntenan. A. 177. A section of the astragalus of a young person, exhibiting the reticular cancellous structure of the whole bone, the cancelh being largest in the centre. 0. C. 206. Huntenan. A. 178. The counterpart o the preceding preparation. 0. C Huntenan. 207. A. 179. The os naviculare of a young person, longitudinally bisected, to show the cancellous structure nearly uniform throughout the bone. 0. C. 208. Huntevian. A. 180. The os cuueiforme internum of a young person, lon- gitudinally bisected, and showing a similar structure. 0 C 209 Hunterian, A. 181. The two middle metatarsal bones of a Fig {Sus serofa), in section. The vascularity is greatest at the spongy extremities. 0. C. 157. Huntenan. A. 182. A longitudinal section of the metatarsal bones of a Calf. Along the middle of this preparation may be observed the progress of the ossiHcation, which afterwards produces a complete ankylosis, and reduces the two to a single cannon- bone. 0. C. 154. Huntenan. A. 183. A similar preparation ; apparently a section of the preceding specimen. 0. C. 155. Huntenan. 40 PHYSIOLOGICAL SKRIEB. A. 184. The exterior section of the same bones. The vessels in the cartilaginous extremity are particularly distinct. 0. C. 156. fhnfenan. A. 185. A metatarsal cartilage of a Calf, injected. The arteries in several parts are of a whitish colour, from a deposit of calcareous earth. 0. 0. 138. Hnnterian. A. 186. A section of the foot of a mature Human Foetus, injected, showing the cartilaginous condition of the bones of the tarsus, with the commencement of ossification in the os calcis and astragalus. 0. 0. 133 d. A. 187. Section of the foot of a Boy 12 years of age, showing the epiphyses of the lower part of the tibia, os calcis, metatarsal and phalangeal bones, injected. The section is through the middle of the first metatarsal bone. 0. C. 133 D a. Presented hy J. Hilton, Es" PHYSIOLOGICAL SERIES. particular being so taut and powerful that the vertebral column, even before the removal of the trunk-muscles, is bent into serpentine curves. Towards the tail both liga- ments are reduced in size. B. 18. Two transverse sections of the vertebral column of a Shad {Clupea alosa), taken from the tnmk (upper specimen) and tail regions respectively, to show the relations of the sub- vertebral ligament to the aorta. B. 19. Anterior portion of the vertebral column, and posterior part of the cranium of a Cod [Gadus morrlma), showing the powerful subspinous ligament. It is partly attached to the arches, as shown in the lower part of the preparation by the removal of the left halves of two of the arches. B. 20. Four vertebree of a Cod {Gadus morrhua) gi^ang an end view of the ligament. Interarcual. B. 21. Seven dorsal neural arches and spines of a Sheep {Ovis aries) showing the yellow elastic tissue (Ligamenta subflava) by which the arches are united. Its probal}le duty is to reestablish the normal curves of the spine after muscular action. At vertebral joint of ribs. B. 22. Six vertebrte of a Snake (Python sehce), with portions of the ribs left attached to the lower three. In front of the joint Fig. 4. X 20. the attachment of the rib to the vertebra is effected by a plate of yellow elastic tissue, the elastic fibres are closely ])acked, parallel to one another, at its fixed ends cartilage FLEXIBLE BONDS OF UNION AND SUl'POKT. 51 matrix and cells are abundant, the fibres terminating in a network after repeated brandling. The ligament probably serves to drag the rib forward after the contraction of the intercostal muscles has pulled it backwards. The lio-ament has been left attached to the vertebrte from which tlie ribs have been removed. (Fig. 4.) Limbs. B. 23. Eight pectoral fin of a Monk-fish {Rhinasguatina), show- ing a series of elastic ligaments situated upon the ventral surface of the fin. The largest and most important of these lio-aments (indicated bv a black bristle) connects the shoulder-girdle with the two anterior basal pterygia ; it hes outside the joint capsule. The remainder of the series are related in a similar manner to the basio-radial and proximal row of interradial joints. On their inner side they are in close connexion with the interarticular fibrous mass and covered on the outside by the perichondrium. No such ligaments are present on the dorsum of the fin. A similar condition was found in Acanthias, but not in Myliohatis or the Skate. B. 24. A longitudinal section through the mesopterygium, a radius, and part of the shoulder-girdle of a Monk-fish {Rhina squatina) , ^ho^'vag the elastic ligament that con- nects the shoulder-girdle with the ventral surface of the pterygium and its relations to the joint capsule. The capsule has been removed from the dorsal surface of the joint. JOINTS. Without known function, mostly the result of periodicity in rate or nature of growth. Plants. B. 25. Terminal branch of a Euphorbia {E. neriifoUa) stained by cupric acetate. The stem is jointed, showing a series of constrictions. The joints do not increase the flexibility of the stem, nor serve as places of ready fracture as in Cacti. They probably only indicate periodicity in growth, and have no function. The terminal segments bear large leaves. Royal Garden Kexo. e2 52 PHYSIOLOGICAL SPiRIKK. B. 26. A similar specimen of E. lactea. The leaves in this plant are minute and borne on the edges of the angular jointed stem. They are soon lost, their duty being performed by the succulent green stem. Roi/al Gardens, Kew. B. 27. A similar specimen of E. glohosa having two flower- bearing branches. As in the former specimen the leaves are minute, soon lost, and borne only on the last formed segments of the stem, the jointed character of which is very marked. Royal Gardens, Keiu. Animals. B. 28. Hydroecium of a Hydroid zoophyte [Aglaophenia viyrio- phylhirn), with a drawing of the structure of its stem (hydrocaulus). The stem is composed of about seven or eight tubes uniformly arranged in the internodes, but that divide into two bundles at the nodes where they are arranged in one plane. This allows of movement through about 40° at the oblique surface of the node. Hincks, Brit. Hydroid Zoophytes, vol. i. p. 290. B. 29. Portions of a Fan-coral (Melitodes ochracea). From one piece the crust has been removed. Another is in section. The axis is divided into a series of nodes and internodes. At the nodes the spicules forming the axis are loosely arranged, partly fused together at their extremities, or united by a small amount of horny matter. The jointed character of the axis does not increase its flexibility, and apparently only indicates a periodic change in its nature. Joints ( = nodes) , points of development of organs, separated by internodes that etFect the necessary elongation. Plants. B. 30. Nitella flexilis, with drawing of the minute structure of growing end. The stem consists of greatly elongated cells, each forming an internode, their protoplasm is reduced to a thin layer lining the cell-wall, abundant cell-sap occupying the interior ; the nucleus has disappeared by fragmentation, JOINTS. 53 In the nodes the cells are small, filled with protoplasm, and retain their nucleus. From the nodes are developed all organs and accessory parts. Presented hy 11. Groves, Esq. B. 31. Portion of the stem of Eqidsetam maximum with whorls of branchlets cut short. The stem is hollow from the more rapid growth of the circumference than the centre. It is jointed, being divided into nodes from which the branchlets spring, and from which all organs are formed. At the nodes the vascular bundles communicate with one another, and a septum is formed across the cavity of the hollow stem. Royal Gardens, Kew. B. 32. Three portions of the stem of Wheat {Triticum vulgare), with leaves attached. The stem is hollow from the rupture of the pith. At the nodes a septum separates the neigh- bouring cavities ; at this point the vascular bundles of the leaf (veins) are continued into those of the stem (cauhne bundles). Presented hy Prof. G. Stewart. B. 33. Terminal branch of Yellow Jasmine (Jasminum nudi- fiorum). The stem is solid owing to the pith not being ruptured. The insertions of the leaves indicate the nodes. Presented by Prof. C. Steivart. Joints that allow of continuous growth. Animals. B. 34. Two specimens of the test (corona) of an Echinus {K acntus). They are about half-grown. One has been bi- sected, the other has had the five sets of ambulacra!, and five sets of interambulacral plates detached. One of each of these has had each plate separated. There are 82 plates in each ambulacrum, and 46 in each interambulacrum ; the total number in the test, including the 10 apical plates, being 650. Each plate enlarges by additions to its borders their number being increased by the formation of fresh plates at the apex of the test. Presented by Prof. C. Stewart. 54 PHYSIOLOGICAL SERIBS. B. 35. A Trunk-lisli {Oslracion quadricornis) . The greater part of its body is protected by hexagonal bony plates that increase in size by additions to their margins. B. 36. Separated bones of the carapace and plastron of a Tortoise (Damonia reevesii). The bones are mostly of dermal origin, and are siitiirally attached to one another. Growth is effected at the sutural margins. B. 37. Cranium from a child aged about 9 years. It is com- posed of separate bones united suturally. Increase in size is effected by additions to their edges, so that the capacity of the skull may keep pace with the growth of the brain. The adult size of the cavity in the frontal region is attained in the second year, the posterior region at a somewhat later period. The position of obliterated sutures arc indicated by blue dots. Merkel, Beitr. z. Anat. u. Embryol. als Festgabe zum Henle, 1882, p. 164. Joints that by allowing motion, diminish the risk of fracture. Plants. B. 38. A multinucleate calcareous Alga (Ci/niopolia barhaia), with a drawing of its structure. Each branch of the thallus consists of a central tube of cellulose lined by chlorophyll- containing protoplasm. It is slightly constricted at short interAf-als. The constricted part (node) is flexible. The iuternodes bear wdiorls of lateral branchlets, those at the proximal end being short, but increasing in length to the distal end. Between the branchlets carbonate of lime is deposited, rendering the internode rigid. The flexibility at the node greatly dimishes the risk of fracture. This plant is found on the shores of the Tropical Atlantic. PI. IX. fig. 1. Presented hy G. R. M. Murray, Esq. Cramer — Ueber die verticillirten Siphonen {JYeomeris und Cymopolia). B. 39. A similar specimen and drawing of another calcareous multinucleate Alga i^Halimeda tuna). The fan-shaped PI. XII. C . Ste-//tu-t, del . I.CYMOPOLIA BARBATA. Dicuffu/ntiiic aiurt.X 40. 2.HALIMEDA TUNA. Jivnq . secb. X 4-0 . » f PI. XIII. C.St ewa-i-b del I.AMPHIROA EPHEDR/EA. Lon^.seci/.X 50 . 2.CRISIA EBURNEA. X50. » PI. XIV I It JOINTS. 55 ualcareous internodes are united by a bundle of about 20 noncalcified tubes forming the node. The calcareous matter is most dense at the external surface of the internode. From the shores of the Mediterranean and West Indies. PI. IX. fig. 2. Presented by G. R. M. Murray, Esq. B. 40. A calcareous Alga, one of the Floridese {AmpJdroa ephedrcea), and drawing of its structure. The flexible nodes consist of noncalcified cells. In the internodes the cell- walls are calcified, stiff and brittle. When fresh or moist the plant readily bends without breaking, but when dry the slightest touch causes fracture. From the Cape of G. Hope and AustraHa. PI. X. fig. 1. Presented hy G. R. M. Murray, Esq. Animals. B. 41. Zoarium of a Bryozoan {Crisia eburnea), and drawing of its structure. The tubular polyp -chambers (zooecia) have rigid and brittle calcareous walls. The first zocecium of each branch has a horny ring within the calcareous walls that are here partly interrupted so as to expose the ring and allow of flexion. This part constitutes the node. The radical tubes by which the animal is attached have many such nodes. PI. X. fig. 2. B. 42. Zoarium of another Bryozoan {Cellarla sinuosa), and drawings. The branching is dichotomous. Each branch normally commences by 8 special zooecia having their interior fined by flexible horny matter. The calcareous walls break at this point, exposing the dark horny material as a flexible bond of union forming the node. These con- necting zooecia are devoid of the polypide present in all the others, they also differ in other respects. PI. XI. fig. 1. B. 43. Cellaria sinuosa. Being preserved in spirit the black horny material of the nodes is more distinct, as it can be seen through the calcareous walls of the zocecia. B 44. Small portion of a Bryozoan {Memhranipora membranacea) incrusting a Seaweed (Lotmmarm sacc/iamia), with drawing of structure. The seaweed is constantly bending in the 56 PHYSIOLOOICAL SERIES. water ; if the Menibranipora were rigid it would be the subject of frequent fracture; this is prevented by each calcareous lateral wall of the zooecium having two places where it is membranous and flexible. The dorsal and ventral walls are entirely membranous. PI. XI. fig. 2. Nitsche, Zeitschr. wiss. Zool., Bd. xxi. 1871, p. 418. B. 46. Second antenna of a Lobster (Ilomarus vahjaris), with drawing of its structure. The proximal segments can alone be moved by muscles. The long and tapering distal part (flagellum) is composed of calcified rings connected by flexible noncalcified cuticle. This structure, that greatly diminishes the risk of fracture, is common to all filamentous antennse. The filamentous portion of the antenna that is naturally straight has been coiled to show its flexibility. Joints that allow of voluntary motion. Invertebrata. B. 46. Spines and plates from the test of a Sea-urchin (Hetero- c.entrotus mammillatus, fam. Echinometradse), some in section, with diagrams showing relation of soft parts. The spine articulates by a ball-and-socket joint, the surface of the socket being about half that of the mamelon. B. 47. A similar preparation and diagram of Phyllacanthus im. perialis, fam. Cidaridaa. A pit in the centre of the socket and mamelon gives attachment to a round ligament. This is also present in the Diadematidse and Echinoidea Irregu- laria. The middle spine in the preparation is from P. baculosa, the dried soft parts are still attached, the round ligament has been painted blue. Prouho, Arch. Zool. Exp., t. v. 1887, p. 252. B. 48. Separated dorsal and ventral valves of a Brachiopod {Magellania lenticular is), with the hinge-region of another specimen. Two processes of the ventral valve (one painted blue) are locked in depressions (one painted red) in the dorsal valve. The valves can only be completely separated by fracture. The articulation admits of but slight motion. JAW. 57 B. 49. Three of the six joints of the great claw (chela) of a Lobster (Homanis vulgaris). The dorsal surface of the ischiopodite and meropodite is flattened, a single fulcrum being formed by the entire length of the dorsal border. In the joint between the meropodite and carpopodite there are two fulcra, each about 14 mm. long. The outer fulcrum is overlapped by a process of the meropodite. The joint between the carpopodite and propodite has two fulcra: the dorsal one, as in the previous case, is formed by a narrow line of noncalcified cuticle, by which a special calcified process of the carpopodite is attached to the pro- podite ; on the ventral side the fulcrum is formed by thick cuticle not attached to any process. The regions of both fulcra are strengthened by a hollow process of the carpo- podite that overlaps the propodite. On the dorsal side the process has a semicircular groove, into which fits a semi- circular ridge on the propodite. On the ventral side the ridge is borne by the carpopodite, the groove by the pro- podite. In each the fulcrum corresponds with the centre of the semicircle. The fulcra have been painted blue. Presented hy Mr. R. Barton. Langer, Denkschr. d. k. Akad. Wiss. Wien, Bd. xviii. 1860, p. 101. B. 60. The dorsal and ventral portions of the joint between the carpopodite and propodite of the great claw of a Lobster, separated to show the special semicircular articular surfaces, the ridge on the ventral being borne by the carpopodite, on the dorsal by the propodite. This probably increases the strength of the articulation. Vertbbeata. JAW. . B. 51. Joint between the right maxillary and mandibular carti- lages of a Skate {Raja hatis). The articular surface of the maxillary cartilage is irregularly rounded, that of the mandibular concave. The upper border of the latter shows a notch through which protrudes a synovial pouch 8 mm in diameter. The synovial membrane has a few small fringes, but is apparently healthy. The cavity of the joint 58 fHYSlOLOGIOAL SERIE8. is tilled in all adults by loose lenticular or irregular-shaped bodies. Some are of minute size, but the great majority have a uniform diameter of 2 nun. They consist of mucin, fibrin, and branched cells. Those removed from this joint are shown below ; in bulk they measured between 6 and 7 CO. B. 52. Portion of the skull with the right mandible of a Duck- billed Platypus {Ornithorhynclms anatmns). The temporo- maxillary joint has been opened from the front, to show the absence of any interarticular substance between the two joint surfaces. The condyle of the mandible is convex and laterally expanded, the corresponding glenoid cavity being concave from side to side, convex from before backwards. The movements of the jaws are probably very simple in character. For Mammalian Joints. — Parsons, Jour, of Anat. & Physiol, vol. xxxiv. 1899, p. 41. B. 53. Right half of the skull of a Tasmaniau Devil {Sarcophilus [^Dasyurus] ursiniis) showing the temporo-maxillary joint. The glenoid fossa, as in placental Carnivora,is deeply concave from before backwards, with well-marked pre- and post- gleuoid processes. The condyle of the mandible is strongly convex and fairly accurately fits the glenoid cavity. There is no interarticular cartilage. B. 54. Part of the skull with the left mandible of an Armadillo [Dasypus sexcinctus). The cavity of the temporo-maxillary joint has been exposed from the outer side to show the small size and simple flattened character of the articular surfaces and the entire absence of any interarticular cartilage. B. 55. A section through the temporal bone and condyle of the lower jaw of a Beaver [Castor pbcr), gi^'i'^g ^ posterior view of the double articular cavity and intermediate sub- stance; and showing that the capsular ligament between the interarticular substance and glenoid cavity is longer than that between the interarticular substance and condyle JAW. 59 of the lower jaw ; both of which, therefore, in extensive motions of the jiiw backwards and forwards, must move together upon the temporal bono. 0. C. 261. Ilunterian. B. 56. The left ramus of the lower jaw, and part of the cranium of a Porpoise {Plwccena phoccena) . A section has been made through the joint, to show the fibrous connecting- substance in situ. 0. C. 240 a. van Beneden, Arch, de Biol., t. iii. 1882, p. 669. B. 57. A section of the ligamentous substance that unites the lower jaw to the cranium in the Whale. 0. C. 240. "The articulation of the lower jaw is not by simple contact either single or double, joined by a capsular ligament, as in the quadruped; but by a very thick intermediate substance of the ligamentous kind, so interwoven that its parts move on each other, in the interstices of which is an oil. This thick matted substance may answer the same purpose as the double joint in the quadruped." —Hunter, Phil. Trans. 1787, vol. Ixvii. p. 384. Hunterian. B. 58. Half of the fibro-cartilaginous mass that formed the squamoso-mandibular articulation of a young female Balcmoptera acuto-rostrata. 0. C. 240 b. Perrin, Proc. Zool. Soc. 1870, p. 805. B. 59. The interarticular ligainentous substance from the joint of the lower jaw of the Elephant {Elephas indicus). The surface adapted to the temporal bone is concave in the lesser and convex in the larger diameter ; the opposite or lower surface presents a deep, oval excavation for the reception of the condyle of the jaw. 0. C. -262. Hunterian, B. 60. A vertical section of the interarticular substance from the joint of the lower jaw of a younger Elephant, showing the degree, of concavity on each side, so well calculated for adapting two convex surfaces to each other. A bristle is placed in an orifice leading out of the lower cavity. 0. C. 263. Ilunterian. PHYSIOLOGICAL SERIES. B. 61. The counterpart of the preceding preparation, divided horizontally, and exhibiting a disposition of the outer ligamentous fibres in concentric circles, similar to the inter- vertebral substances of the spine. 0. C. 264. Hunterian. B. 62. Right temporo-maxillaryjointofa Horse {Efjuu, cahallus). The joint-cavity has been opened from behind to show thi; slightly curved character of the articular surfaces and the thin plate of fibro-cartilage intersposed between them. The cartilage assists in adapting the articular surfaces to one another during the complicated rotary and gliding movements of which the jaw is capable. Chauveau & Fleming, 'Anatomy of the Domestic Animals/ 1873, p. 138. B. 63. A similar preparation of the left temporo-maxillary joint of a Sheep {Ovis aries). The surfaces of articulation are more flattened than in the Horse, and eminently adapted for gliding movements. Two slips from the masseter are attached to the antero-lateral surface of the capsule ; one near its upper border, the other where it is attached to the interarticular substance. B. 64. A vertical and longitudinal section of part of the lower jaw and temporal bone of a young Lion [Felis led), exhibiting the interarticular substance extending through the whole of the joint, and dividing it into two synovial cavities. 0. C. 258. Hunteinan. B. 65. The corresponding section of the same parts, showing the similar conditions. 0. C. 259. Hunterian. B. 66. A vertical and transverse section of part of the lower jaw and temporal bone of a Lion, showing the extent of the joint in that direction and the form of the interarticular substance, convex from side to side above, concave below. 0. C. 260. Hunterian. • B. 67. A vertical section of part of the temporal bone and ramus of the lower jaw of a Human subject, exhibiting the forms JAW. 61 of the glenoid and condyloid articular cavities, and of the intermediate fibrous cartilage. 0. C. 265. " Just under the beginning of the zygomatic process of each temporal bone, before the external meatus auditorius, an oblong cavity may be observed ; in direction, length, and breadth, in some measure corresponding with the condyle of the lower jaw. Before, and adjoining to, this cavity, there is an oblong eminence placed iu the same direction, convex upon the top in the direction of its shorter axis, which runs from behind forwards ; and a little con- cave in the direction of its longer axis, which runs from within outwards. It is a little broader at its outer extremity, as the outer corresponding end of the condyle describes a larger circle in its motion than the inner. The surface of the cavity and eminence is covered with one continued smooth cartilaginous crust, which is somewhat ligamentous, for by putrefaction it peels off, like a membrane, with the common periosteum. Both the cavity and eminence serve for the motion of the condyle of the lower jaw. The surface of the cavity is directed downward ; that of the eminence downward and backward, in such a manner, that a traiis- verse section of both would represent the italic letter/. Though the eminence may, on a first view of it, appear to project consider- ably below the cavity, yet a line drawn from the bottom of the cavity to the most depending part of the eminence is almost hori- zonta"!, and therefore nearly parallel with the line made by the grinding surfaces of the teeth in the upper jaw ; and when we consider the articulation farther, we shall find that these two lines are so nearly ijarallel, that the condyle moves almost directly forwards in passing from the cavity to the eminence ; and the paraUelism of the motion is also preserved by the shape of an intermediate cartilage. "In this joint there is a moveable cartilage, which, though common to both condyle and cavity, ought to be considered rather as an appendage of the former than of the latter, being more closely connected with it, so as to accompany it in its motion along the common surface of both the cavity and eminence. This cartilage is nearly of the same dimensions with the condyle, which it covers; is hollowed on its inferior surface to receive the condyle : on its upper surface it is more unequal, being moulded to the cavity and eminence of the articulating surface of the temporal bone, though it is considerably less, and is therefore capable of being moved with the condyle from one part of that surface to another. Its 62 PHYSIOLOGICAL SEniES. texture is ligamento-cartilaginous. This moveable cartilage is connected with both the condyle of the jaw and the articulating surface of the temporal bono, by distinct ligaments, arising from Its edges all round. Tliat by which it is attached to the temporal bone is the most free and loose ; though both ligaments will allow an easy motion, or sliding of the cartilage on the respective sur- faces of the condyle and temporal bone. These attachments of the cartilage are strengthened, and the whole articulation secured, by an external ligament which is common to both, and which is fixed to the temporal bone and to the neck of the condyle. On the inner surface of the ligament which attaches the cartilage to the temporal bone, and backwards, in the cavity, is placed what is commonly called the gland of the joint ; at lease, the ligament is there much more vascular than at any other i^art."— Hunter, On the Teeth, 4to, 1st edit., 1771 , p. 9. Hnnfenan. VEETEBRAL COLUMN. ACENTROUS. Gadow & Abbott, Phil. Trans., vol. clxxxvi. 1895, p. 163, & Gadovv', vol. clxxxvii. 1896, ji. 1. B. 68. Three portions of the uotochord of a Sea-Lamprey {Petromyzon marimcs), showing a series of cartilaginous dorsal arches lying in the lateral walls of the mass of con- nective tissue that surrounds the neural canal. In the anterior region of the body (middle specimen) the arches are irregular in shape, but further back, in the region of the liver (lower specimen), they are more regular. The upper specimen is a transverse section through the anterior region and shows the relation of the arches to the neural canal. Schneider, ' Beitrage zur vergleichenden Anatomic und Entwicklungsgeschichte der Wirbelthiere,' Berlin, 1879, p. 51. B. 69. Portion of vertebral column, and head of a Sea-Lamprey (Petromyzon mannus). The ventral portion of the noto- chord and cartilaginous cranium has been removed in front VERTEBRAL COLUMN. 63 to show the pointed extremity of the notochord surrounded by the cranial cartilage. 0. C. 230 C. B. 70. Anterior portion of a Glutinous Hag {Myxine glntinom), showing the notochord. 0. C. 230. Jfnnterkm. B. 71. Portions of the vertebral column of a Sea-Cat (Chimcera ■monstrosa). The colunni, although without any suggestion of vertebral bodies, is potentially chorda-centrous owing to the invasion of the chordal sheath by cells from the skeleto- o-enous layer. The continuous notochord is surrounded by a delicate elastica externa and a very thick elastica interna (chordal sheath). The latter is to a considerable extent cartilaginous, and is divided into an inner and outer layer by a series of narrow calcified rings, contiguous with one another and far more numerous than the basi-dorsalia. The dorsal arches are composed of basi-dorsalia, inter-dorsalia, and supra-dorsalia ; towards the middle of the body the supra-dorsalia disappear, and in the tail-region they are followed by the inter-dorsalia. The ventralia consist of a double row of small irregular cartilages. A certain number of the anterior arcuaUa are fused together and enlarged to provide a support for the anterior spine of the dorsal fin. The skull articulates to the vertebral column by a diarthrodial joint. The upper specimen is the anterior portion of the vertebral column, in it some of the.dorsalia are outlined in black. The next specimen (part in sagittal section) is taken from the middle of the body ; beneath is a transverse section from the same region. The two lower specimens are from the tail. Hasse, ' Natiirliches System der Elasmobranchier/ Jena, 1882, p. 25. B. 72. Specimens of the calcareous rings from the chordal sheath of a Sea-Cat (Chimcera mediterrama) . The rings have the form of narrow fibrous bands, with a deep concavity running round their outer side. They are composed of dense calcified connective tissue, the fibres and cells of which are packed closely together with their long axes mainly parallel 64 PHYSIOLOGICAL SERIES. to the circumference of the ring. Two isolated rings are mounted above, and below are two pieces (one in section) composed of several contiguous rings. Hasse, 'Naturliches System der Elasmobrancbier/ Jena 1882, p. 33. B. 73. Transverse sections of the spine of the Southern Chimajra [Callorhynchus anstraUs), in which the notochord is persis- tent, but has a thicker fibrous sheath, in which there is no trace of calcification : the vertebr£e are indicated by the small cartilaginous dorsalia and ventralia. 0. C. 236 a. Hasse, Nat. Syst. Elasmobrancbier, 1882, p. 30. B. 74. A portion of the notochord of a Sturgeon. A longi- tudinal section has been made on one side, which exposes some small cavities in the centre. 0. C. 232. Hunterian. B. 75. A longitudinal section of the notochord and sheath of a Sturgeon, showing the thickness of the sheath, and exposing a larger central cavity in the notochord. 0. C. 233. Jlimterian. B. 76. A transverse section of the spine of a Sturgeon {Acipenser sturio). It shows the persistent continuous notochord: the inner layer of the fibrous sheath of the notochord has increased in thickness. In the skeletogenous tissue are de- veloped distinct, firm, and opaque cartilages — the dorsalia, which consist of two superimposed pieces on each side, the basal portion bounding the neural canal, the apical poi'tion a superior canal, filled by fibrous elastic ligament and adipose tissue : above this is the single cartilaginous supradorsal. The ventralia are now distinctly developed, and joined together b}' a continuous expanded base, forming an inverted arch beneath the notochord, for the vascular trunks. 0. C. 234. Hunterian. B. 77. A longitudinal section of the anterior part of the spine of a Sturgeon, which shows the gradual contraction of the notochord as it approaches the head. The whole spine VERTEBRAL COLUMK. 65 being composed of very elastic materials, renders the existence of joints and vertebral bodies unnecessary. 0. C. 235. Hunterinn. V. Ebner, Sitz. d. k. Akad. Wiss. Wien, Bd. civ. Hft. 3, 1895, p. 149. Chord ACENTRO us. B. 78. Portions of the precaudal cartilaginous vertebral column of a Greenland Shark {Lonmargushorealis), part in section. Each vertebra consists of cartilage only. A disc having a thickness at its centre of 4 mm., increased to 10 mm. at the lateral margins, and dorsally enlarging so as to come in contact with those of neighbouring vertebras, but ventrally separated by prolongations of the interventralia, represents the centrum. It is formed in the sheath of the notochord (= chorda-central type). Continuous with the dorsal sur- face of the centrum are a pair of basidorsalia that commence by a broad base. The intervals between the basidorsalia are filled by the interdorsalia. Lateral processes, the basi- ventralia and interventralia, largely repeat the features of the dorsalia. The pairs of dorsalia and ventralia both fuse in the mid line. The notochord is largely persistent. Hasse, Nat. Syst. Elasmobranchier, 1882, p. 55. B. 79. Portions of the vertebral column of the same fish from the junction of the caudal and precaudal regions. There is no trace of calcification. Red glass rods indicate some of the openings for the roots of the spinal nerves. B. 80. Portions of the vertebral column of a Fox Shark {Alopecias vulpes) taken from the precaudal region. In the lower specimen the anterior vertebra are in sagittal section; the posterior vertebrae show the superficial striations upon the centra due to the edges of a series of radiating calcified plates, the relative size and position of the arcual cartilages is also shown. The upper specimen is a transverse section through the middle of a centrum, and shows the radiating calcified plates and the relations of the bases of the arches to the centrum. 66 PHYSIOLOGICAL SEKIKS. B. 81. Portion of the verteljral column of* a Fox Shark {Alopecias mdpes) from tlu? caudal region, showing especially the dorsalia and interdorsalia ; also ventralia and interventralia. B. 82. Portion of the vertohral column (part in section) of a Porbeagle Shark (^Lamna cornuhica) showing a flattened continuous band of yellow elastic tissue closely adherent to its cartilaginous spinous processes. The biconcave (amphi- cojlous) vertebral bodies are well developed. Their cartilage is calcified on their articular surfaces, and around the sheath of the notochord, from which point four sets of calcareous plates extend to the circumference, their intervals being occupied by cartilage. The cartilaginous neural arches (dorsalia and interdoi-salia) show the openings for the dorsal and ventral roots of the spinal nerves, into the former green and into the latter red glass rods have been introduced. On either side of the ventral surface of the column are cartilaginous plates, the ventralia and interventraUa. Hasse, Nat. Syst. Elasmobranchier, 1882, p. 214. B. 83. Transverse s(;ction of the vertebral column of a young Basking Shark ( Selarlie maxima) that measured twelve feet in length. The notochord is continuous, enlarging at intervals to form the soft intervertebral discs. Concentric rings of calcificatiou traverse the cartilaginous body. These rings are interrupted by the cartilaginous con- tinuations of the neural arches (dorsalia) and transverse processes (ventralia). The concentric plates are in later life followed by radiating ones. 0. C. 237 B a. Hasse, Nat. Syst. Elasmobranchier, 1882, p. 236. B. 84. Transverse section of half a vertebra of an older example of a Basking Shark {S. maxima) shoM'ing the radiating plates of calcified cartilage that invest the concentric ones. There are also fine radiating lines of calcification between the concentric plates. B. 86. Terminal caudal vertebrae of a Piked Dog-fish (Acanthias vulgaris) showing besides the vertebi-fe, the horny fila- ments that support the extreme edge of the fin-membrane. 0. C. 279 D. Presented by W. Cliff, Esq. Hasse, Nat. Syst. Elasmobranchier, 1882, p. 93. VERTEBRAL COLUMN. 67 B. 86. Portion of the precaudal vertebral column including six vertebrae of a Skate {Raja hatis). 0. C. 237 d. B. 87. Three portions of the vertebral column of a Ray {Raja clavata) taken respectively from the anterior, median, and posterior regions of the body. The column is formed in its anterior part (upper specimen) of a single rigid mass of carti- ■ lage, in which the only indication of segmentation is afforded by the nerve-foramina (31 pairs) on each side. The charac- ters of this part of the column have probably arisen in response to the demand for additional strength to support the enlarged pectoral fins. Somewhat posterior to the shoulder- girdle, the segmented notochord appears ; its upper and lateral surfaces are enveloped by basi- inter- and supra- dorsalia and basiventralia (the latter are at first continuous with the basidorsalia) . In the middle specimen the transition from trunk to tail is shown ; the basiventralia become separated from the basidorsalia^ migrate to the ventral aspect of the notochord and there, with the addition of inter- ventralia, form the haemal arches. The interdorsalia are gradually suppressed. The lower specimen shows the degenerate condition of the tail. Hasse, Nat. Syst. Elasmobr. 1882, p. 168. Aechcbntrous. B. 88. Portions of the vertebral column of Lepidosteus os-seus. The vertebral bodies are opisthocoelous and developed entirely from the arches without invasion of the chordal sheath by skeletogenous cells (archcentra). In the adult the notochord is altogether suppressed. The three upper specimens are taken from the precaudal region, the two lower from the caudal. Balfour & Parker, Phil. Trans., vol. clxxii. 1882, p. 386. B. 89. Portions of the trunk region of the vertebral column of a Cod {Gadus nmrluuC). Each vertebral body consists of a deeply biconcave disc of bone, smooth and hard upon its concave surface, but of looser texture outside. It is attached to the bodies of neighbouring vertebrae by the edges of its cavities by means f2 68 PHYSIOLOGICAL SERIES, of fibrous tissue. The biconical space enclosed between each pair of vertebral bodies is filled with a gelatinous material that represents the remains of the notochord. The articulation of the bodies with each other is rendered more rigid by an overlapping of processes on the bodies by corresponding projections of the neural arch and transverse processes of the succeeding vertebra. An anterior view of a vertebra is shown above ; below, 11 vertebrae (the first 5 of which are in sagittal section) are seen from the left side. Scheel, Morph. Jahrb., Bd. xx. 1893, p. 1. B. 90. The caudal extremity of the vertebral column of Lepido- siren paradoxa seen from the left side. In this and in the other Dipnoi the notochord is obliterated towards the end of the tail and replaced by a number of rectangular blocks of cartilage, each surmounted by a variable number of arcualia. They probably do not represent vertebral bodies. Klaatsch, Morph. Jahrb., Bd. xx. 1893, p. 151. B. 91. A longitudinal and vertical section of two vertebrse of a Siren (^Siren laceTtina). The articular surfaces of the bodies of the vertebrae are hollowed out as in fish, but the cavities are occupied by ligamentous fibres disposed in concentric circles : the articular processes are joined by capsular and synovial membranes. 0. C. 246. Hunterian. Mivart, Proc. Zool. Soc. 1870, p. 260. B. 92. A longitudinal and vertical section of the cervical vertebrae of a Turtle {Clielone mydas), the bodies of which are connected by ligamentous substance passing between the whole of their articular surfaces. These surfaces, in the first, second, and third vertebrae, are convex at the anterior part, and concave at the posterior; in the fourth they are convex at both ends; the anterior surface of the fifth is concave, the posterior plane; both surfaces are plane in the sixth ; but the posterior surface of the seventh vertebra is convex. 0. C. 248. Hunterian. VERTEBRAL COLUMN. 69 B. 93. Eight dorsal vertebra3 of Monitor Lizard (Varanus salvator) . A sagittal section has been made of the anterior vertebrae, it shows the joint cavities between the procoelous vertebral bodies. The articulations of the ribs are seen on the posterior vertebrae. B. 94. Vertebrfe of V. salvator in horizontal longitudinal section, showing the procoelous intervertebral joints. B. 95. Vertebrae with portions of ribs attached of Boa constrictor {Python sehoi) . A strong common ligament extends along the ventral faces of the bodies. The capsular ligament of the ribs is most strongly developed dorsally and ventrally, anteriorly the joint-cavity is bounded by a plate of yellow elastic fibrous tissue. Eochebrune, Jour, de I'Anat. et Physiol., t. xvii. 1881, p. 185. B. 96. A longitudinal and transverse section of the bodies of the vertebras of a large Serpent {Python tigris), exhibiting the forms of their articular surfaces, 0. C. 250 c. B. 97. Left half of a portion of the vertebral column of a Boa {Python tigris), the ribs being left attached. 0. C. 250 B. B. 98. Two cervical vertebrae and one dorsal of a Crocodile (C. acutus) showing, in end view, the structure of the intervertebral joint. Between each pair of centra there is a fibro-cartilaginous intervertebral disc, that, owing to the procoelous character of the joint, has the form of an obtuse hollow cone. Along the outer margin of the disc there is a strong fibrous band united superficially to the outer ligament but free towards the disc, except at a point on either side. This disc is the homologue of an intercentrum (basi-venti'als) . A blue rod has been inserted in each specimen between the fibrous band and the disc. Gegenbaur, Jena. Zeitschr., Bd. iii. 1867, p. 400. B. 99. Two dorsal vertebrae of a Crocodile {C. acutus) from which the spines and dorsal arches have been removed to 70 PHYSIOLOGICAL SERIES. show the intervertebral fibrous ham]. A green rod and black bristles have been inserted in different places between it and the intervertebral disc. B. 100. A longitudinal horizontal section of two cervical verte- br£B of an Ostrich {Struthio camelus), exposing the cavity of the joint which unites these vertebrse ; here, the anterior surface is convex, the posterior concave. 0. C. 251. JIunterian. B. 101. A longitudinal vertical section of two anterior dorsal vertebrae of the Ostrich, the bodies of which are articulated by a capsular ligament, as in the preceding specimen; the articular surfaces are saddle-shaped, with the two faces in reversed positions. The canal for the passage of the medulla spinalis is enlarged near the articulation, to prevent its being compressed in the motions of that part of the spine. 0. C. 252. Hunterian. B. 102. Vertebra of Tachyglossns [Eclddna] aculeaia, and left halves of two others, showing the intervertebral substance, and its central cavity. 0. C. 246 A. B. 103. A transverse section of the intervertebral substance of the Bottlenose Whale {Ht/peroodon rostrata). It is 153 mm. in diameter ; the external 13 mm. appears of uniform consistency, and exhibits very little of the fibrous character. The rest of the substance, to within 16 mm. of the centre, is composed of ligamentous fibres arranged in concentric circles, and at nearly equal distances; the remaining central part appears to be wholly occupied by glairy matter. 0. C. 245. Hunterian. Hunter, On the Whale, Phil. Trans., vol. Ixxvii. 1781, tab. xix. B. 104. A longitudinal section of two caudal vertebrae of a Horse {Equus cahallus). These vertebrae form a remarkable con- trast to those of fishes, as they present to each other convex, instead of concave, surfaces. 0. C. 242. Hunterian. HIBS. 71 B. 105. A single vertebra from the tail of a Horse, exhibiting a transverse section of the intervertebral substance, the ligamentous tibres of which are disposed in concentric circles, which recede from each other as they approach the centre, and have a glairy fluid in the interspaces. 0. C. 243. Hunterian. B. 106. Atlas vertebra of a Seal [Plioca vituUna) . A stout wedge- shaped ligamentous band is attached to the antero-ventral surface of the vertebral body. It lies dorsal to the anterior occipito-atlantal ligament with its narrow free border directed forwards, and tills up the hollow between the two occipital facets. The odontoid process is embraced between this ligament and the transverse ligament of the atlas. EIBS. ■B. 107. A dorsal vertebra, and the vertebral extremity of a rib of an Ostrich, showing that the latter is articulated by distinct capsular ligaments to two different parts of the vertebra ; viz., the parapophysis below, and the diapo- physis above. The orifice for the admission of air into the rib may be observed in the angle of the neck and tubercle. 0. C. 253. Hunterian. B. 108. A portion of the sternum and the sternal extremity of the rib of an Ostrich, showing that this part is also articulated by distinct capsules to two points of the sternum. The sternal and vertebral portions of the rib are also articulated by a synovial capsule. 0. C. 254. Hunterian. B. 109. Some dorsal vertebra with portions of ribs attached from the Duck billed Platypus [Ornitliorhynclms anatinus). A transverse ligament unites the heads of the ribs, it hes on the ventral surface of the intervertebral disc. B. 110. Bodies of the 3rd to the 11th dorsal vertebrae of a Mole [Talpa europa^a) with the heads of the corresponding ribs. A black bristle has been placed beneath the transverse hga- ments ; these lie on the dorsal surface of the intervertebral disc, and each is attached to the heads of a pair of ribs. Sutton, Jour. Anat. & Phys., vol. xviii. 1884, p. 225. 72 PHYSIOLOCaCAL SRIllES. B. 111. The 2nd to the 9th dorsal vertebra of a Fox-Squirrel {Schirus luclovicianus), with tlie articular extremities of the corresponding ribs. The dorsal arches have been removed to show a transverse ligament passing between each pair of ribs, froin head to head, on the dorsal surface of the inter- vertebral disc. The ligaments (behind which a black bristle has been placed) are only present between the heads of the third to the ninth pairs of ribs. B. 112. A dorsal vertebra, and the articular extremities of four ribs of a Horse {Equus cahallus). These are attached by capsular ligaments to the angles of the body of the vertebra ; they have also a strong transverse ligament which passes from the head of one rib, dorsally to the intervertebral substance, to the head of the opposite rib; thus connecting them firmly to each other, and to the vertebra. 0. C. 257. Hunterian. B. 113. Centrum of a dorsal vertebra of a Tapir (Tapinis terres- tris) with the heads of the corresponding pair of ribs, showing a similar transverse ligament. B. 114. Portions of four dorsal vertebrae of Sheep {Ovis aries) with extremities of ribs attached, showing the strong trans- verse ligament that unites the heads of the ribs. Presented by P. D. Cogliill, Esq. B. 115. One mid-dorsal, and two last dorsal vertebrse, also articu- lar ends of ribs, showing transverse ligament uniting their heads. From a Seal {Phoca vituUna), seven days old. The ligaments proper to each pair of ribs are two in number, they traverse respectively the dorsal and ventral surfaces of the intervertebral disc. Presented hy the Zoological Society. B. 116. The 7th to 11th dorsal vertebrre of a Dog {Canis famili- aris), with the heads of the corresponding ribs attached. The neural arches have been removed to show four stout transverse ligaments. They are only present between the heads of the seventh to the tenth pairs of ribs. SHOULDER-GIRDLK. 73 B. 117. Tenth to thirteenth dorsal vertebrtE of a Chimpanzee {Anthropopithecus troglodytes), showing ribs attached to all the transverse processes. SHOULDEE-GIBDIiE. B. 118. Right scapula and clavicle of a Tasmanian Devil [Sarcophilus [Dast/urus] ursinus). The clavicle is attached by ligament to both the coracoid and acromion processes of the scapula. B. 119. Anterior part of the sternum vi'ith the clavicles of an Armadillo [Dasypm sexcinctus) , showing the sterno-clavicu- lar articulation. Each clavicle is attached to one of the two anterior processes of the expanded manubrium sterni by a ligament in which are embedded two nodules of cartilage. Owing to the position of the sternal end of the clavicle directly dorsal to the manubrial process, the ligament under- goes a ventral twist in passing from one to the other. Hoffmann, Niederl. Arch. f. Zool., t. v. 1879-82, p. 66. B. 120. Left scapula and clavicle with the distal ends of the first two ribs of Three-toed Sloth {Bradijpus tridactylus). The clavicle is rudimentary and represented only by a nodule of bone imbedded in a ligament that passes between the sternal extremity of the first rib and the coracoid. Humphry, Jour. Anat. & Physiol., vol. iv. 1870, p. 26. SHOULDER. B. 121. The right anterior extremity of a Bull - Frog [Rana cateshiana) . The shoulder-joint is laid open, and the capsule turned back, to show an interarticular ligament passing from a depression in the head of the humerus to a depression in the centre of the glenoid cavity, and attached also to the inferior margin of that cavity. A bristle is passed behind this ligament : a small synovial bag projects into this joint just above the insertion of the ligament. This additional security against dislocation of the shoulder- joint appears to be necessary in the frog, to obviate the 74 PHYSIOLOGICAL SERIKS. effects of the shock, or impulse, which the anterior ex- tremities receive when the animal alights from a leap. 0. C. 255 k. B. 122. Eight shoulder-joint of a Duck-billed Platypus ( OrmVAo- rhynchus anatinus). The glenoid cavity has the form of a groove with open ends, deeply concave in a dorso-ventral direction, but slightly convex transversely. The head of the humerus is laterally expanded and constitutes a roller- shaped condyle of slightly crescentic form ; the hollow of the crescent fits against the lower (coracoid) lip of the glenoid groove and is connected to it by a stout gleno-humeral ligament. The form of the articular surfaces and looseness of the capsule except where it forms the gleno-humeral liga- ment allow of considerable rotation of the humerus. Attached to the apex of the internal tuberosity there is a small loose nodule of bone on which the subscapularis muscle is inserted. This bone has been compared to the os humero- scapiilare of the bird. B. 123. Eight shoulder-joint of an Opossum {Didelphys marsu- pialis). The capsule has been opened to expose a stout gleno-humeral ligament, which arises from the glenoid border beneath the biceps tendon, passes diagonally across the joint-cavity free of the capsule, and is attached to the inner side of the head of the humerus. The gleno-humeral ligament in this and the following specimens is apparently the middle gleno-humeral ligament of human anatomy. B. 124. Left shoulder- joint of a Tasmanian Devil [Sarcopliilus [Dasyurus] ursinus) showing a similar gleno - humeral ligament. B, 126. Left shoulder of a Six-banded Armadillo (Dasypus sexcinctus). A blue glass rod has been placed beneath the gleno-humeral ligament that is free in the joint-cavity. A green glass has been passed beneath a special thickening of the external wall of the capsule. B. 126. Eight shoulder-joint of Kine-banded Armadillo (^Tatusia novemcincta) . A bristle has been passed below the free gleno-humeral ligament SHOULDER. 75 B. 127. Right shoulder-joint of a Hedgehog [Erinaceus europanis) . A black bristle has been placed below the delicate gleno- humeral ligament. B. 128. Right shoulder-joint of a Rabbit {Lejnis cuniculus), showing the free gleno-humeral ligament. B. 129. Right shoulder-joint of Gruinea-pig (Cavia porcellm), showino; o-leno-liumeral ligament. Presented by F. S. Eve, Esq. B. 130. Right shoulder-joint of Capybara (Hydrochcerus caj^y- bara), show gleno-huraeral ligament. B. 131. Right shoulder-joint of Coypu [Myocastor coypus), showing a gleno-humeral ligament. B. 132. Left shoulder-joint of a Beaver {Castor canadensis) , showing a gleno-humeral ligament. Presented by J. B. Sutton, Esq. B. 133. Left glenoid cavity of foetal Elephant [Elephas indieus). A fold of the capsule is situated near the dorsal border of the glenoid cavity. The glenoid hgament may be seen beneath the coracoid process. B. 134. Right shoulder-joint of a Dog (Cams familiaris), showing a gleno-humeral ligament. B. 135. Left shoulder-joint of Colobus vellerosus, showing a fold of capsule representing the gleno-humeral ligament. B. 136. Right shoulder-joint of Orang-Outang {Simia satyrus), showing a fold of the capsule representing the gleno- humeral ligament. Presented by Victor Horsley, Esq. B. 137. Left shoulder-joint of Orang-Outang [Simia satyrus), ahowing a gleno-humeral ligament. B. 138. The parts constituting the left Human shoulder-joint. The capsular ligament is laid open to expose the head of the humerus, and the tendon of the long head of the biceps 7G PHYSIOLOGICAL SERIES. muscle passing along the upper part of the articular cavity, and attached to the marginal ligament of the glenoid cavity of the scapula. The section of the capsular ligament shows its relative thickness at the upper and lower part. 0- C. 255. Hunterian. ELBOW. B. 139. Right elbow of a Frog {Rana clamata) in which the articular surfaces have been exposed. The bone formed by the fusion of radius and ulna articulates by a simple concave facet with the single hemispherical condyle of the humerus. The internal epicoudyle is prominent, and bears on its median surface a facet, which engages with a corresponding facet on the inner surface of the ulna head. The form of the articular surfaces indicates a very consider- able freedom of movement in all directions except towards the inner side, where it is checked by the epicondylo-ulnar articulation. Cuenod, Internat. Jour. Anat. & Physiol., vol. v. 1888 p. 390. B. 140. Right elbow-joint of a Turtle {Clielone mydas). The articular surface on the hiunerus for the radius is rounded and smaller than that for the ulna. A fold of the capsule projects from behind. Presented by George Ring, Esq. B. 141. Right elbow-joint of a Goose {Anser domesticus) opened from the flexor aspect to show the form of the joint surfaces. The curvatures of the two humeral condyles are eccentric to the axis of rotation of the joint in different directions, so that in extension the radius is drawn towards the shoulder and the ulna protruded — in flexion the reverse. The horizontal gliding of the radius upon the ulna is assisted by the presence of articular facets where the two bones touch, and by a band of fibro-cartilage (indicated by a black bristle) stretched between the dorsal borders of their heads. By this movement of the radius, the hand, upon extension of the elbow, is automatically brought into line with the ELBOW. 77 forearm. The flexor surface of the capsule is greatly strengthened by more or less independent ligaments. Garrod, Proc. Zool. Soc. 1875, p. 82. B. 14:2. Left elbow-joint of Duck-billed Platypus {OraitJw- rhynchus anatinus). The humerus has been displaced to show the form of the joint surfaces. The ulna lies directly behind the radius, and their combined articular surfaces form a simple concavity which plays upon a corresponding single convex facet on the humerus. The joint forms a perfect hinge. Tornier, Morph. Jahrb., Bd. xii. 1887, p. 407. B. 143. Right elbow-joint of a Koala (Phascolarctus oinereus), showing the form of the articular surfaces. The ulna lies slightly to the inner side of the radius ; its articular surface is composed of two distinct parts — one of which, as in the Monotremes, forms a simple concavity with that of the radius and articulates with a single convex facet on the humerus ; the other has the appearance of a lateral excres- cence upon the inner side of the first and articulates with a separate convexity on the head of the humerus. B. 144. A vertical section of the articular extremities of the Human humerus and nlna, showing the trochlea of the former bone to which the articular cavity of the latter is adapted, and the mode in which the power of the triceps brachii is increased by the projection of the olecranon, its point of insertion, beyond the centre of motion. 0. C. 273. I-Iunteria7i. B. 146. Elbow-joint of Man dissected to show the form and position of the orbicular ligament. The ligament is a strong fibrous band attached to the anterior and posterior margins of the lesser sigmoid cavity ; it encircles the head of the radius and is attached, proximally to the capsular ligament, distally by a loose thin membrane to the neck of the radius. It assists in pronation and supination by allowing the radius to freely rotate upon its own axis. Cathcart, Jour. Anat. & Physiol., vol. xix. 1885, p. 355. T8 PHYSIOLOGICAL SERIES. WRIST. B. 146. m^ht wrist-joint of a Duck-billed Platypus {Ornklw. rhynchus anatiniis). The scaphoid and lunar are fused to form a single bone articulating with the radius and to a slight extent with the ulna. Two large lateral prominences on Its proximal surface engage with corresponding depi-essions upon the radius and ulna, while the groove between them is occupied by a process of the radius. This interlocking between the proximal row of carpals and the bones of the fore-arm restricts the movements of the wrist to simple flexion and extension. B. 147. Left wrist-joint of a Spider Monkey {Ateles melanocldr) . An interarticular fibro-cartilage (triangular cartilage) is inserted between radius and ulna in the distal radio-ulnar joint. The articulation between the ulna and the cuneiform bone is separated by an antero-posterior septum from that between the radius and the scaj)hoid and semilunar. B. 148. Left wrist-joint of Papio [Cynocej^lialus'] spldnx. The posterior radio-carpal ligament consists of two fasciculi, that converge from their separate origin on the radius to a common insertion on the cuneiform. The styloid process of the ulna is prominent and articulates with the cuneiform and pisiform bones. There is a partial septum between the two halves of the joint. Presented hy Prof. F. G. Parsons. B. 149. A dissection showing the fibro-cartilage at the radio- ulnar articulation of the left side of a Man. 0. C. 268 A. Corner, Jour. Anat. & Physiol., vol. xxxii. 1898, p. 272. DIGITS. B. 150. A vertical section of the fore-foot of a Horse {Equus cahallus) . In this are illustrated all the contrivances for augmenting the moving powers, and ditfusiug the concentrated forces of pressure and percussion. The interphalangeal joints are imperfect hinges, that allow of slight lateral movements in addition to those of rEL\aC GIRDLE. 79 flexion and extension. The posterior ligament of the 1st interphalangeal joint is of great power to withstand the tendency to overextension due to the weight of the hody : it is united laterally to the tendon of the flexor sublimis and extends up the posterior surface of the 1st phalanx to become confounded with the sesamoid ligaments of the metacarpo- phalangeal joint. 0. C. 279. PELVIC GIBDLB. B. 151. A section of the sacrum and pelvic girdle of a Man. The dorsal portion of the sacro-iliac articulation is flrmly united by fibrous tissue, the ventral shows a distinct synovial cavity. HIP. B. 152. The OS innominatum and femur of a large Tortoise (Testudo indica). The hip-joint is laid open to show that the ligamentum teres is absent. This simple form of joint obtains at the hip in all Chelonian reptiles. 0. C. 255 a. Presented Inj W. CUft, Esq. B. 153. The right os innominatum, os marsupiale, and femur of a Duck-billed Platypus {Ornithorh/nchus anatinus). The anterior part of the capsule of the hip-joint has been removed to expose the head of the thigh-bone, and the cotyloid cavity, and to show that the ligamentum teres is absent in this species. B. 154. The left os innominatum, os marsupiale, and femur of Echidna aculeata. The head of the femur is turned out of the cotyloid cavitv, to show the absence of the ligamentum teres. There is a foramen at the back part of the cotyloid cavity, which is deficient at that part, as it is in birds. 0. C. 255 D. B. 155. Left hip-joint of a Koala (PJiascolarctus cinerem) . The joint has been opened to show the ligamentum teres, 80 PHYSIOLOGICAL SERIES. extending from the transverse ligament to the articular cartilage of the head of the femur. (No depression can be seen on the head of the femur in the dried bone.) B. 166. The right os innominatum and femur of the Two-todd Sloth [Choloepus didactylus) . The hip-joint is laid open to show absence of the ligamentum teres. 0. 0. 255 H. B. 157. Upper part of the femur of a Two-toed Sloth {CJwloepus didactylus). There is no ligamentum teres, but upon the femur head there is a flattened area, at the spot where in other mammals the ligament when present is usually attached. B. 158. Left half of the pelvis and upper part of the femur of a Three-toed Sloth {Brady pus tridactylus) . The joint-cavity has been opened to show the entire absence of a ligamentum teres. B. 169. Right hip-joint of an Armadillo (Dasypus sexcinctus). The joint-cavity has been exposed to show the great size of the ligamentum teres. It has an extensive origin from the anterior margin of the cotyloid notch and from the capsule in its neighbourhood. B. 160. Right hip-joint of a young Pangolin [Maiiis penta- dactyla). The ligamentum teres is absent. Presented hy Dr. J. Anderson. B. 161. Right hip-joint of a fcetal Elephant {Elephas africaniis). The ligamentum teres is absent. B. 162. The head of the right femur of an Elephant {Elephas indicus) three years old. The cartilaginous articular surface is uniformly smooth, having no depression for the insertion of the ligamentum teres. 0. C. 255 E. B. 163. Left hip-joint of Pi^ocavia [flyraa;] capensis. The liga- mentum teres is fused with the capsular ligament. HIP. 81 B. 164. Right hip-bone of a foetal Horse {Equus cahallus) with a portion of the head of the femur. The ligamentum teres is separable into two well marked divisions. The one (cotyloid) lies entirely within the joint-cavitj ; the other (pubio-f'emoral) passes from the femur head through the cotyloid notch and is attached to the pubis, pubic tendons of the abdominal muscles, and tendon of origin of the pectineus. Its close relation to the pectineus has led some to regard the ligamentum teres as a divorced tendon of that muscle. Sutton, Ligaments, etc., London, 1882, p. 38. B. 165. The left os innominatum and femur of a Seal {Fhoca vitulind). The capsule of the hip-joint is partly removed, and the head of the thigh-bone turned out of the cotyloid cavity, showing it to be quite smooth, without any depression for a ligamentum teres, which is absent in this animal : the cotyloid cavity has, however, the usual notch and depression, the latter being filled with fatty membranous substance. 0. 0.255 B. B, 166. Eight OS innominatum and femur of a young Walrus ( Odohcenus [ Trkhechiisl rosmarus) . The femur is dislocated and the capsule of the joint removed to show the absence of the ligamentum teres. 0. C. 255 B«. B. 167. The left os innominatum and upper part of the femur, with a section of the lumbar, sacral, and coccygeal verte- brae, of an Orang-Outang {Simia saf.yriis). The hip-joint is laid open, and the head of the thigh-bone dislocated and turned forwards, to show its smooth and uniform spherical articular surface, having no depression for a ligamentum teres, which is absent in this species. 0. C. 255 I. B. 168. Right hip-joint of a young male Orang-Oulang {Simia satyr us). The ligamentum teres is absent, but a peculiar mark on the head of the femur may indicate its presence at a still earlier period. 82 PHYSIOLOGICAL SERIES. B, 139. Right hi[j-joiiit of a Chimpanzee (AnthrojjjpUhecus troglodtjtes), showing the ligamentum teres. B. 170. The parts constituting the Human hip-joint of the right side. The anterior part of the capsular ligament is turned back to show the extent to which the synovial membrane is reflected over the anterior part of the neck of the thigh- bone ; the thickness of the ligamentous part of the capsule is also shown by the section. In the cotyloid cavity may be observed the ligamentum teres, round which a bristle is tied, and the depression containing the fatty and synovial substance. 0. C. 256. Hunierian. KUEE. B. 171. The parts constituting the knee-joint of an Ostrich {Slru' thio camelus), injected. A section has been made through the patella, and the anterior part of the joint is laid open to show the crucial ligaments, and a very large tendon passing through the joint to be attached to the front of the external condyle ; also a tendon passing through a synovial sheath in the ligament of the patella, in an oblique direction from the femur to the tibia. Posteriorly, the capsular ligament is removed, to show the semilunar cartilages and the ligament connecting the external one to the head of the fibula, which in this class of animals is articulated with the external condyle of the femur, and forms part of the knee-joint. The blood-vessels upon the inner condyle are successfully filled, and exhibit numerous mutual anastomoses as they approach the articular cartilage, forming what Dr. Hunter termed " the Circulus articuli vasculosus ; the vascular border of the joint." 0. C. 272. Hunterian. B. 172. The parts constituting the knee-joint of the Omitho- rhynchus anatinus. The articular cavity is divided into two compartments by a continuation and extension of the ligamentum mu- cosum from the back of the patella to the crucial ligaments; KNEE. 83 there being one synovial cavity common to the patella and anterior part of the femur, with the internal condyle and tibia, containing the internal semilunar cartilage ; and a second common to the external condyle of the femur and tibia, with the head of the fibula, in which is contained the external semilunar cartilage. The fibula has been rotated forwards to show a laro-e facet upon the inner surface of its head, that articulates partly with the femur and partly with the outer surface of the head of the tibia. B. 173. Right knee-joint of Koala {Fhascolarctus cinereas) opened from behind. The head of the fibula shares in the formation of the joint, articulating by a small facet with the side of the external condyle of the femur. A small nodule of cartilage (fabella) in the tendon of the gastrocnemius, articulates by a facet with the posterior surface of the head of the fibula. There is no bony patella. B. 174. Lower portion of the right hind limb of a Tasmanian Devil {Sarcophilus \_Dasyurus] ursinus) showing the knee- and ankle-joints. The head of the fibula has a small facet upon its apex for articulation with the femur, and a larger one upon its outer side which articulates with a nodule of bone attached by ligament to the shaft of the femur above the external condyle and to the head of the fibula. The external lateral ligament has been divided to show another ligament beneath it, that passes diagonally backwards from the lower and outer surface of the external condyle of the femur, and is attached by two branches to the anterior and posterior surfaces of the head of the fibula. B. 175. Right knee-joint of a Fruit Bat {Ptero'pas ediuardsii) opened from in front. Tiiere are no interarticular cartilages. B. 176. The parts constituting the knee-joint of a Calf [Bos tuurus). The patella is turned down, to expose the anterior part of the joint ; and on the opposite side the capsular ligament g2 84 rHYSIOLOGlCAL SERIES. is removed, to show the intervening semilunar cartilages and crucial ligaments. This joint has in this animal a partial septum extending across it (apparently a greater development of what is called Ligamentum mucosum in the human subject), which divides it into an anterior and posterior cavity. 0. C. 296. Bvnterian. B. 177. A vertical section of the parts constituting the knee- joint of the same animal, showing the ligamentum mucosum, producing an almost distinct anterior cavity between the patella and condyle of the femur, and a posterior one between the trochlea and head of the tibia. 0. C. 270. Hunterian. B. 178. The counterpart of the preceding preparation. 0. C. 271. Hunterian. B. 179. Left knee-joint of Lemur mongoz, opened from behind. The posterior extremity of the external semilunar cartilage is attached by a long ligament to the outer surface of the internal condyle of the femur. In a similar way the internal semilunar cartilage is attached by ligament to the inner surface of the head of the fibula. The external lateral ligament is double ; its inner fasciculus may represent a divorced portion of the popliteus tendon. Presented hy Prof. F. G. Parsons. B. 180. The parts constituting the Human knee-joint. The patella and part of the capsule are turned down to show the ligamentum mucosum within the joint and the anterior crucial ligament ; the extent of the synovial membrane and the Kne of its reflection upon the condyles of the femur ; the capsule is removed from the posterior part of the joint to show the interarticular semilunar cartilages and the posterior crucial ligament. The lateral ligaments and part of the tendon of the popliteus are also shown. 0. C. 265 a. B. 181.. The interarticular semilunar cartilages from the Human knee-joint, injected ; showing their transverse comiecting ANKLE. 85 ligaments, and the different character of the upper and lower parts for adapting a convex to a flat surface. 0. 0. 266. Hunterian. B. 182. Small portion of the articular end of a femur. The cartilage has been broken, it shows a vertical striation of the fractured surface due to the cells being mostly dis- posed in vertical rows. A thin layer of the free surface projects, the cells being flattened and in horizontal layers. 0. 0. 267. Hunterian. William Hunter, Phil. Trans., vol. xlii. 1742-3, p. 514. Hammar, Arch. f. Mikr. Anat., Bd. xliii. 1894, p. 813. ANKLE. B. 183. The tendons and ligaments of the joint between the tibio-tarsus and tarso-metatarsus of an Ostrich ; the thick- ened tendon has been removed to show the interarticular cartilage at the back part of the joint. 0. 0. 275 A. B. 184. Right ankle-joint of a Duck-billed Platypus (Onii^/to- rhynchus anatinus) . The internal malleolus of the tibia is strongly developed and articulates by an outwardly turned rounded head with a deep pit on the inner surface of the astragalus — an arrangement strikingly similar to the peg and socket articulation between the fibula and astragalus in the Sloths. The tibio- and fibulo-tarsal joints are entirely separated from one another by an antero-posterior synovial partition. B. 185. Right ankle-joint of an Opossum (Didelphys marsupialis) . There is a well-marked semilunar interarticular cartilage between the fibula and astragalus. It is attached in front to the astragalus, behind to the fibula. B. 186. Left ankle-joint of a Tasmanian Devil (Sarcophilus [Dasyurus'] ursinus). An interarticular fibro-cartilage is interposed between the fibula and astragalus. The natural irregularities in the posterior margin of the tibio-fibular articular surface are equalised by two nodules of bone imbedded in the posterior ligament. 86 PHYSIOLOQICAL SERIES. B. 187. Left ankle-joint of a Tliree-toed Sloth {Bradyjms iridac- hjhis). The cavity of Ihe joint has been opened in front to show a curious peg and socket arrangement by which the intuiuing of the sole by the powerful tibialis anticus is facilitated, and outward displacement of the foot during this movement prevented. The peg is formed by a conical extension of the lower extremity of the fibula ; its point is directed diagonally inwards and downwards, and fits into a corresponding concavity in the upper and outer surface of the astragalus. A somewhat similar contrivance, though far less strongly marked, is found in certain Monkeys, e. cf. Na&alis, in which the sole of the foot is inturned in climbing. Humphry, Jour, of Anat. & Physiol., vol. iv. 1870, p. 22. B. 188. Eight ankle-joint of a Spider Monkey (A teles melanocJiir). The external lateral ligament is in three fasciculi similar to those present in Man. The posterior portion of the capsular ligament has been reflected upwards to show the inter- articular cartilage attached to it. B, 189. Lower ends of left tibia and fibula of a Spider Monkey {Ateles melanochir) , showing the interarticidar cartilage projecting from the posterior part of the capsule. B. 190. Right ankle-joint of Papio [ Cynoceplialus] sphinx. The external lateral ligament is in two fasciculi, corresponding respectively to the middle and posterior fasciculus of Man. Presented by Prof. F. G. Parsons. MUSCULAR AND ALLIED SYSTEMS. 87 c. MUSCULAR AND ALLIED SYSTEMS. PLANTS. C. 1. Two branches o£ Desmodium gyrans showing the diurnal and nocturnal positions of the leaves. There is no special- ised motile organ, but the entire leaf- stalk (petiole) is straight during daylight from the uniform turgescence of its cells. In the dark, the cells of the upper half of the leaf-stalk becoming more turgid, causes the downward curvature. Sachs, Physiology of Plants (Eng. trans.), p. 623. C. 2. Portion of a ternate leaf of Erythrina corallodendron, to show the part between the leaflet and petiole by which the motion of the leaflets takes place after sunset. 0. C. 28. " There is an action in plants which appears to be the contrary of expansion ; it may be considered as a relaxation, or an action of those parts antagonizing the others which acted through the day, or at other periods, and it takes place at the time these other parts cease to act. "This action has hitherto been considered as analogous to sleep in animals ; whereas, sleep is a total loss of the sensitive principle, and all the actions dependent on volition for the time ; and, therefore, can only take place in animals endowed with sensation. It is rather a defect in the animal, than an action, or the exertion of a principle."— Jo7m Hunter, MS. Groonian Lectures, No.l. [The various actions that take place in plants at the close of day, are described by Linnaeus in Amcenitates Academicce, iv. p. 333, under the title Somnus Plantarum.'] Hunterian. C. 3. Leaves of Iledysarum gyrans, in which the small lateral leaflets have a power of moving up and down, with a varying degree of velocity, and without any mutual uniformity or co-operation. These motions take place independent of external stimulus. 0. C. 31. Hunterian. 88 PHYSIOLOGICAL SEfllES. C. 4. Poi-tion of stem and leaves of Hedysarum gyrans. TLe main leaves assume the normal diurnal and nocturnal positions. The small lateral leaflets are in constant spontaneous periodic movement occupying a few minutes, the temperature must be high (at least 22° C). C. 6. Two portions of stem with leaves attached of a Scarlet- runner (Phaseolus multiflorus). A swollen region at the bases of the main leaf-stallcs and leaflets constitutes a special motile organ. In the absence of light the upper halves of the motile organs of the leaflets become more turgid, causing the leaflets to droop ; at the same time the motile organ of the main leaf-stalk becomes more turgid below, thus raising the leaf-stalk into a more vertical position. C. 6. A branch of Mimosa pudica, with two leaves ; one of them is in the expanded state ; the other contracted, but erect. 0. C. 29. " Although one only of the pinnules be touched, the contractile movement is quickly propagated aloug the other three: it consists of an approximation of the upper surfaces of the opposite subleaflets to each other, with an overlapping of those of the same side." — John Hunter, MS. Oroonian Lectures, No. 1. Hunterian. C. 7. Two portions of stem with leaves attached of a Sensitive Plant {Mimosa pudica). The diurnal and nocturnal positions are shown. The nocturnal position is rapidly assumed on the slightest irritation. It probably is of use in protecting the leaves from injury by tropical rain-storms. Special motile organs are well defined. ANIMALS. INVERTEBRATA. C. 8. Part of the margin of a large Medusa {Rhizostoma coimlea), on the inferior edge of which the membrane is disposed in numerous minute plic£e, running in the direction of the circumference, and giving to it a fibrous or muscular appearance. MUSCULAR AND ALLIED SYSTEMS. 89 The muscle-fibres of MedusEe are derived from the ecto- derm, and each consists of an elongated contractile fibril connected with either a superficial epithelial cell or with one that has migrated into the mesogloea. The fibres are mainly present as a circular layer in the sub-umbrella, and in this region show a very definite transverse striation, connected no doubt with the sharp swimming contractions of the bell. 0. C. 55. Hunterian. 0. & K. Hertwig, Der Organismus dur Medusen, Jena, 1878, p. 7. C. 9. Two specimens of the Sea- Anemone {Actinia mesembryan- themwn). The upper of the two is expanded, the lower contracted. The contraction is due to muscle-fibres situated in the mesoderm, but for the most part, as in Medusae, either connected with or derived from the ectoderm. The fibres are smooth. 0. C. 55 A. 0. & R. Hertwig, Jena. Zeitschr., Bd. xiv. 1880, p. 42. C. 10. Masticatory apparatus (lantern of Aristotle) and neigh- bouring portion of the test of Ecliinus esculentus. The points of the five teeth project through the central opening in the peristomal membrane. Each of the teeth is supported by a " pyramid," composed of two " alveoli/^ connected at the base by two pieces forming the " trans- verse arch.'^ The pyramids (jaws) are locked together by five falces or braces ; over these are the five slender radii or compasses. The muscles may be divided into four groups, viz. : five pairs of protrusors of the jaws, they arise from the actinostome between the auriculae, and are chiefly inserted into the transverse arch ; five pairs of retractors of the jaws and openers of the mouth, arising from the auriculse and inserted near the tips of the jaws ; five that arise from, and are inserted into, the neighbouring faces of the pyramids, that approximate the teeth ; and five inter- radials, that prevent the downward dragging of the outer furcate ends of the radii when the jaws are protruded, they might slightly tend to protrude the jaws, but this is already provided for by other muscles. All the muscles PHYSIOLOGICAL SERIES. are nnstriped. Five pairs of ligaments (indicated by black bristles) spi-ing from the actinostome and are attached to the furcate outer ends of the radii ; they prevent the raising of this end by the contraction of the interradial muscle. C. 11. Section of an Ecliiuothurid. (Asthenosoma liystrix) showing the arrangement of the muscles, by whose contraction the alterations in form of the creature are produced. Two of the five pairs of muscle-sheets are shown. They He in the boundary lines between the ambulacra and inter- ambulacra, taking origin from the outer ends of the ambulacral plates. Each muscle-sheet is of crescentic form and composed of more or less isolated bundles. The latter radiate from a central tendon to the test. The fibres are smooth. P. & F. Sarasin, Ergebnisse Naturwiss. Forschungen auf Ceylon, Bd. i. 1888, p. 93. C. 12. A Sea-Cucumber [Holotliuria tubulosa) o\>Qn from the dorsum to show the muscles of the body and cloaca. The muscles of the body-wall consist of an outer circular and an inner longitudinal layer. The latter is strongly developed and is broken up into five radial bands, each divided down the middle by a conspicuous furrow. Each band originates from the calcareous ring around the oesophagus and extends without interruption to the posterior extremity of the body. A large number of fine branching strands of muscle radiate outwards from the cloacal wall to the neighbouring parts of the body- wall. They act as dilators of the cloaca. C. 13. Another specimen of Ilolothuria tuhulosa, cut open to show the muscles of the body-wall. 0. C. 56. Huntenan. C. 14. The dermo-muscular tube of a Gephyrean worm [Sipunculns opened along the dorsal surface. There are three muscle-layers in the body-wall, whose fibres (beginning with the outermost layer) have, respec- tively, a circular, diagonal, and longitudinal direction. In each layer the fibres are grouped together in regular par- allel bundles. There are four retractor muscles of the intro- MUSCULAli AND ALLIED SYSTEMS. 91 vert, which originate from the longitudinal layer on a level with the anus and are inserted at the base of the tentacles. The individual muscle-fibres consist of an outer sarcolemma, a spirally fibrillated contractile cortex and a central proto- plasmic portion. Upon the right, several of the longi- tudinal bundles have been removed to show the underlying diagonal layer, and on the left the circular layer is similarly exposed by the removal of both longitudinal and diagonal layers. 0. C. 56 A. Andrese, Zeitschr. f. wiss. Zool., Bd. xxxvi, 1882, p. 228. C. 15. A similar preparation of Pliascolosoma vulgare. In this Gephyrean the muscles of the body-wall are far more delicate than in Sipunculus and are arranged in two layers only — longitudinal and circular— in both of which the fibres form a continuous sheet. The course of the fibres in the two layers can be seen where black paper has been inserted beneath them. 0. C. 56 B. C. 16. Right half of a Sea-Mouse {Aphrodite aculeata) showing the muscular system, which in this worm attains a very high degree of complexity. The muscle-layers of the body- wall are broken up into a number of individual muscles, the most conspicuous of which are six longitudinal bands— a pair along the dorsum contiguoiis with each other, a ventral pair separated by an interval of 7 mm., and a single band along each side. The dorsal and ventral bands are contin- uous from end to end of the body, but the lateral bands are interrupted and firmly attached to the body-wall between each segment by a tendinous intersection. The muscles of the outer (circular) layer form a network of diagonal and trans- verse bands that pass between and superficial to the longi- tudinal bands. The interstices between them are occupied by the hepatic caaca. A large series of perpendicular and diagonal muscles traverse the body-cavity between each segment, and each parapodium has its own particular pro- trusor and retractor muscles. 0. 0. 57 A a, C. 17. Portion of a Nereis {Nereis foliosa) showing two series of muscles, which extend along the dorsal aspect from one 92 PHYSIOLOGICAL SERIES. end of the animal to the otlier ; tliese are intersected at regular distances, corresponding to the breadth of the seg- ments. 0. C. 58. Quatrefages, Ann. Sci. Nat., ser. 5, t. xi, 18(J9, p. 309. C. 18. Two specimens of a Leech [Ilirudo medicinalis) . The upper specimen is a transverse section taken through the middle of the body. The viscera have been removed to show several muscular strands passing perpendicularly through the body from the dorsal to the ventral wall, their con- traction flattening the body for swimming. These muscles lie between the gastric pouches within metamerically disposed connective-tissue lamellae. The individual muscle- fibres are branched at either end. The lower specimen shows the longitudinal muscles which form the inner and most powerful layer of the body-wall. They are specially developed along the ventral mid-line. The muscle-fibres are spindle-shaped cells composed of longitudinally fibril- lated cortex of contractile substance, surrounding a central core of undifferentiated protoplasm within which lies the nucleus. The protoplasm of the core extends to the peri- phery of the cell between the cortical fibrils. 0. G. 57 A. Leuckart, Die Parasiten dos Menschen, Bd. i. 1894, p. 568. C. 19. A Leech {Hirudo medicinalis) , having part of its external tesument dissected off to show its longitudinal subcutaneous muscles. 0. C. 57. Ilunterian. C. 20. A Brachiopod ( Terebratella cruenta) from which the viscera and a portion of the left side of the valves have been removed to show the valvular and peduncular muscles. The former — concerned in opening and closing the valves — consist of two pairs of occlusors and a pair of divaricators. The two occlusors of either side arise from the dorsal valve slightly in front of the hinge ; for the first part of their course they are independent and fleshy, but about the middle of the body they assume a tendinous appearance, unite with one another, and are finally inserted by a common expanded MUSCULAR AND ALLIED SYSTEMS. 93 end to the ventral valve. The fibres of the posterior occlusors (indicated by black paper inserted beneath them), unlike those of all the other muscles, are transversely striated. The striped muscle probably first suddenly closes the valves, the closed state being maintained by the un- striped anterior occlusors. The divaricators rise from the ventral valve alongside the insertion of the occlusors, and are inserted upon the cardinal processes of the dorsal valve external to the hinge-fulcrum. The peduncular muscles give rise to the slight movements of the valves upon the stalk ; there are two pairs passing to either valve from the sides of the peduncle. Presented hy Prof. G. B. Howes. Hancock, Phil. Trans., vol. cxlviii. 1858, p. 795. C. 21. A Cirripede {Lepas anatifera) dissected from the right side to show the muscular system. The most important muscles are : — An adductor, passing transvei'sely between the scuta, for the closure of the valves ; a group of longitudinal muscles on the carinal body-wall, apparently to retract the animal into its shell ; a series of muscles passing transversly from side to side in the position of the decapod sternum ; and the various muscles of the appendages. The majority of the muscle-fibres are transversely striated, but smooth fibres occur in the adductor muscle, mantle and peduncle. 0. C. 54 A. C. Darwin, Monograph of the Cirripedia, Ray Soc. 1851, p. 39 ; Gruvel, C. R. Acad. Sci., t. cxxiii. 1896, p. 68. C. 22. The stem of the Eared Barnacle {Conchoderma aicrita), deprived of its external theca to show two series of oblique muscular fibres which arise from a central lino or tendon on one side of the stem, and, winding spirally round, are inserted into a similar line on the opposite side of the stem. Beneath these oblique fibres, whose office is to compress the peduncle, others may be observed which are longi- tudinalj for the purpose of shortening the peduncle. 0. 0. 62. Hmitericui^ PHYSIOLOGICAL SERIES. C. 23. The sheath of an Acorn-shell (Balanus porcalm), kid open to show the attachments of the muscles to the moveable opercular valves. 0. C. 54. IJunterian. C. Darwin, Monograph of the Cirripedia, Ray Soc. 1854 p. 01. C. 24. Longitudinal section of a Lobster {Homarus vulgaris), showing the muscles attached to the right half of the body. The chief muscles are indicated by numbers as follows. I. Adductor of the eye-stalk. 2. Anterior gastric. 3. Levator of antenna. 4. Depressor of antenna. 5. Sternal levator. 6. Adductor of mandible. 7. Posterior gastric. 8. Tergo-epimeral. 9. Flexor of coxopodite of chela (acting as an adductor of the whole leg). 10. Extensor of basipodite of chela (acting as depressor of the leg). II. Intersternal. 12. Deep abdominal extensor. 13. Ab- dominal rotator. 14. Deep abdominal flexor (enveloping portion). 14*. Its transverse portion. The most note- worthy of this highly specialised series of muscles are those connected with the movements of the abdomen. They consist of extensors (12), flexors (14), and rotators (13). Both flexors and extensors are composed of super- ficial and deep layers, the former in each case being very poorly developed. The deep flexor is a remarkable muscle both on account of its size and its complicated formation. It rises on either side from abdominal and cephalothoracic regions and extends to the telson, with attachments to each abdominal segment. Broadly speaking, it is com- posed of a central core of fibres around which an enveloping sheet (14) is coiled in a spiral. In each segment offshoots (14*) from the central core run transversely across the body to the central core of the muscle of the other side. The enveloping fibres with additions from the central core are attjiched to the anterior margin of each abdominal sternite. bat the main part of the central coi*e is attached to each tergum above the hinge-line, so that the action of the muscle is partly one of extension although mainly of flexion. Owing to the immobility of the cephalothorax, the MUSCULAR AND ALLIED SYSTEMS. 95 muscles belonging to this region are rudimentary. The muscle-fibres are transversely striated. 0. C. 61 B. Parker & Rich, Macleay Memorial Volume, p. 159. C. 25. Muscles of some right appendages of a Lobster {Bomarus vulgaris). A. Proximal part of a thoracic appendage showing the muscles of the two basal podomeres — coxopodite and basi- podite. Owing to the shortness of these two segments, their muscdes move the limb as a whole, giving rise to adduction, abduction, elevation, and depression. The muscles of both podomeres rise from the endophragm. They are indicated by numbers, thus : — 1. Flexor of coxopodite = adductor of limb. 2. Plexor of basipodite = levator of limb. 3. Extensor of basipodite = depressor of limb. 4. Extensor of coxopodite = abductor of limb. B. An abdominal appendage. The muscles are simple in their arrangement and produce backward and forward movements of the limb and abduction and adduction of the exopodite. 1. Extensor. 2. Flexor. 3. A complex mass of muscle, the proximal part of which forms a continuation of 1 & 2, while the distal part is composed of adductor and abductor of the exopodite. C. The Mandible. The adductors (1, 2, 3) are both numerous and powerful, the abductors (4, 5) compara- tively weak. D. The Tail-fin and Telsou. The main muscles are those concerned with flexion (1) and extension (2) of the tail-fin. Besides these, there are muscles (3, 4) for the adduction of the fin as a whole and (6, 8) of the exo- podite, as well as (5, 7) for the abduction of the exopodite. The last four muscles would also to a certain extent have powers of extension and flexion. 0. C. 61 c. C. 26. A section of the claw of a Lobster {Homarus vulgaris), showing the fibres of the penniform muscle arising from the propodite and inserted into the apodeme of the dactylopo- dite. 0. C. 60. Ilunterian. 96 PHYSIOLOGICAL SERIES. C. 27. A section of the propodite and dactylopodite of the claw of a Lobster, showing the attachment of the penniform adductor from another point of view. 0. 0. 61. Hunterian. C. 28. Portion of the claw of a Lobster [Homarus vulgaris), opened to show the points of attachment of the adductor and abductor of the dactylopodite, and the great contrast between them in size and power. 0. C. 61 d. C. 29. Leg of a Crab {Cancer pagurus) in which the several segments of the limb have been opened to show a pair of involutions of the shell (apodemes), which extend upwards from the upper margin of each segment (podomere) into the cavity of that next above it. They are situated opposite each other in a plane at right angles to that occupied by the fulcra of the joint and serve as surfaces of attachment for the muscles of the leg. Being part of the exoskeleton they are cast with it in exuviation. In each joint the plane of the fulcra is nearly at right angles to that of the next joint above and below, so that by a suitable combination of simple hinge-movements a great range of motion can be attained. 0. C. 61 A. List, Morph. Jahrb., Bd. xxii. 1895, p. 392. C, 30. A section of the larva of a large North American Moth {Bomhyx regalis) showing two lateral series of muscles, which extend along the dorsal and ventral aspects, through the whole length of the body. These are intersected at determinate distances, corresponding to the several segments to which they are to give motion, and which have, also, their own peculiar muscles. 0. C. 59. Hunterian. C. 31. A freshwater Mussel (Anodonta cygnea), of which part of the right valve is removed, and the mantle dissected away, to show a pair of muscles (retractor pedis posterior) going obliquely from their origin upon the valves, in front of the posterior adductor, to their insertion on the foot. 0. C. 53. Hunterian. MUSCULAR AND ALLIED SYSTEMS. 97 C. 32. Right valve of a Mussel (Anodonta eygnen), sliowing the pallial, adductor, and pedal muscles. The former eonsisis of the miistailar border of the mantle. The two adductors of the vahcs are cylindrical muscles of equal size that pai-s transversely from valve to valve at either end of the body. The pedal muscles form the bulk of the foot and extend as a thin envelope over the surface of the visceral mass ; definite anterior and posterior pedal retractor muscles can be distinguished from the general sheet, attached to the valves directly behind the anterior and before the posterior adductors. The contractile cortex of the individual muscle- fibres is either longititdinally fibrillated or shows a double diagonal stria tion probably due to spiral fibrillation. 0. C. 52 A a. Engelmann, Arch. ges. Physiol., Bd. xxv. 1881, p. 553. C. 33. Right valve and muscular parts of an Edible Mussel [Mytihis eduUs). The anterior adductor of the valves is considerally smaller than the posterior. The pedal muscles are very strongly developed. They consist on either side of an anterior retractor pedis, attached to the valve above the anterior adductor, and a series of 6 or 7 posterior retractors attached in a horizontal line anterior to the posterior adductor. The posterior members of the series are inserted upon the margins of the byssal gland. 0. C. 51 c. Sabatier, Ann. Sci. Nat., ser. 6, t. v. 1877, p. 9. C. 34. Right valve and. muscles of a Clam [Mya arenarid). The posterior part of the mantle is modified to form two mus- cular tubes (the siphons) in which the fibres run in circular radial and longitudinal directions. The longitudinal layer is greatly developed, and forms a pair of definite siphonal retractors. They have a very characteristic crescentic attachment to the shell (pallial sinus), continuous with that of the general mantle-border. Midway between the anterior and posterior retractor pedis muscles is a small elevator pedis. 0. (J. 52 A b. C, 35. The valves of a Cockle ( Cardium edule) from which the H 98 PHYSIOLOGICAL SERIES. ventral parts have been romoved, to show the fibres of the two adductor muscles. 0. 0. 52. Ihinterian. C. 36. A vertical section throngh the umbo of a Cockle {Canlinm ednle) . The viscera have been removed to show the posterior adductor and posterior retractor pedis muscles. 0. C. .52 A. C. 37. Two specimens of Fholas [DactyUncC] dudylus, giving a superficial and median view of the muscular system. The anterior adductor muscle lies almost entirely exterual to the hinge-line, attached to a special upward reduplication of the shell, and in consequence its contraction produces an abduction o£ the valves, the elastic ligament that generally performs this function being absent. An additional ad- ductor of the valves is formed by an enlargement of the postero-ventral border of the mantle. In the lower specimen a fan-shaped anterior retractor pedis muscle is shown attached to the anterior and ventral margins of the falciform pi'ocess. 0. C. 53 D. Bgger, Arb. Inst. Wiirzburg, Bd. viii. 1888, p. 151. C. 38. Right valve of a Scallop [Pecten maccimus) with the chief muscles attached. One adductor (the posterior) alone is present, it is readily divisible into two portions — a large anterior part of a greyish colour, and a very much smaller, glistening white posterior part. The grey portion is com- posed of transversely striated muscle-fibres. The white portion consists of longitudinally fibrillated smooth fibres. Experiments show that the grey portion is capable of very rapid and transitory, the white of slow and prolonged contraction. The striped muscle is the main agent in swimming, by the sndden closure of the valves a number of times in rapid succession. It also probably serves, as in the case of Terehratella, for the swift closure of the valves in case of dano-er, the almost tendinous smooth muscle maintaining the closure. The pedal muscles are represented by a much reduced left posterior retractor. 0. C. 51 B. Blanchard, Bull. Soc. Zool. France, t. xiii. p. 76 ; Knoll, S.B. Akad. Wien, Bd. ci. Abt. 3, 1892, p. 481. MUSCULAR AND ALLIED SYSTEMS. 99 C. 39. A vertical section through the umbo of a Scallop {Pc.cten maxlmns)^ showing the position and direction of the ad- ductor muscle. 0. C. 51 A. C. 40. A vertical section o£ the valves of an Oyster ( Ostrea edulis), showing the adductor muscle and the disposition of its fibres' at right angles to the shell. 0. C. 50. Iluntevian. C. 41. The lower flattened A^alve of an Oyster, showing by a transverse section the extent and shape of the adductor muscle. 0. 0. 51. Hunterian. C. 42. Eight valve o£ Anomia ephippium, showing the muscular system. Close in front of the single adductor of the valves is a large posterior retractor pedis which runs transversely across the body from the left valve to the byssal plug. A small fan-shaped muscle runs forward from the anterior edge of the byssal ping and is attached to the right valve near the hinge. There is also a small anterior retractor pedis on the loft side. V. Ihering, Zeitschr. f. wiss. Zool., Bd.xxx. 1878, p. 13. C. 43. A Tectibranchiate mollusc from which part of the dorsal integuments have been removed to show a sheet of inter- lacing muscle-strands beneath. 0. C. 62 A. C. 44. The muscular parts of an Ormer (Haliotis tuherculata) , showing a modirication of the columellar muscle related to the sucker-like character of the foot. The muscle has thn form of a massive truncated cone attached by its apex to the shell slightly to the right of the mid-line and spreading out below to form the substance oli the foot. A section of the muscle has been cut to show its dense felted texture. 0. C 53 B. Presented hy F. Hutchesson, Esq. C. 45. The muscular system of a Limpet {Patella vidgata), showing a somewhat similar modification of the columellar nmscle. At its origin, the muscle has the form of a back- wardly directed horseshoe, from which the muscle-fibres pass directly into the foot converging towards the mid-line. h2 100 rHYSIOLOGICAL SERIES. A shell with the muscle attachments outlined in red is mounted below. 0. C. 52 A c. Jlarvey Gibson, Trans. R. Soc. Edin., vol. xxxii. 18Hr». p. (i"21. C. 46. A Heteropod {Carinarki mediterfanea), from the left side o£ which the integuments have been removed to show the arranoement of the muscles of the body-wall. They consist ol' a nnml)er of anastomosing bands that completely surround the anterior [)arts of the body, and are specially numerous in the fin (chiefly propodium), but become fewer and more scattered in the metapodium. The mesopodium is represented by a sucker upon the ])ostero-ventral margin of the fin. They fall into three main gi-oups according to their direction within the body-wall. i. A series rising from the dorsum and passing diagonally backwards round the sides to the ventral surface. ii. The converse of the preceding, passing backwards from the ventral to the dorsal surface, iii. Very delicate circumferential bands. The muscle-fibres are smooth. Kalide, Zeitschr. wiss. ZooL, Bd. xlvi. 1888, p. .345 : Wackwitz, Zool. Beitr., Bd. iii. 1892, p. 134. C. 47. Two specimens of a Snail {Helix aspersa), showing a com- pound retractor muscle (the columellar muscle) by means of which the whole anterior part of the animal can be withdrawn into the shell. The muscle originates in three bundles from the columella in the third coil of the shell ; the two lateral bundles spread out in the foot on either side of the mid-line, and also give off a slip of attachment to the apex of each tentacle ; the central bundle is inserted into the buccal mass. A small retractor penis passes diagonally across the body-cavity from the penis to the muscular floor of the pulmonary chamber. In the upper specimen the Snail is seen from the right, in the lower from the dorsal aspect. The several muscle-bundles are marked by black paper. 0. C. 53 c. C.48. A Cuttle-fish {Sepia ojirhialis) from which the skin and viscera have been removed to show the muscles. The mantle and funnel have also been longitudinally MUSCULAR AND ALLIED SYSTEMS. 101 divided, and the two halves of each separated to expose the inidei-lving trunk niuscles. The most important of these are the retractor capitis (a compound muscle formed by the fusion of paired median and lateral i-etractors) and the depressor infuudibuli ; these two together pi-obablv represent the columellar muscle of the gastropod. The right tentacle is extended, the left coiled up within its pouch. The muscle-fibres show a very marked double diagonal striation due apparently to the spiral arrangement of the fibrils of the contractile cortex. 0. 0. A 63. Brock, Morphol. Jahrb., Bd. vi. 1880, p. 2U2 ; Bal- lowitz, Arch. f. Mikr. Anat., Bd. xxxix. 1892, p. 291. C.49. A transverse section of one of the arms of a large (Juttle- tish {Oni/choteuthis, Lichtenstein, 'Isis von Oken,'' a.d. 1818, tab. xix. See also Lollgo hanksii, No. 166 D. Catal. Nat. Hist. p. 33), showing the complex arrangement of the muscular fibres. 0.(^.63. Nunterian, C.50. Eight half of the muscular body-wall of a Tunicate {Phallusia mamrnillata) . The nniscle-fibres run in all directions over the body, forming an intricate network. A more regular circular arrangement is noticeable around the oral and atrial apertures. C. 61. Muscular body- wall of a Tunicate (Cioiia iiitestinalis) . The muscle-fibres are arranged more regularly in longi- tudinal and circular layers than in I'hallusia. The fibres that run in a longitudinal direction are gathered together into definite bundles. The individual fibres are very long and of the smooth variety. Roule, C. E. Acad. Sci., t. xcv. 1882, p. 45. C. 62. Asexual form of Salpa a/ricaua maxima, showing the muscular system. The trunk-muscles consist of 9 isolated ribbon-like bands, situated at intervals along the dorsum transverse to the long axis of the body. They extend on either side as far as the mid-lateral line. Around the mouth and atrial aperture are several smaller muscles, the most 102 PHYSIOLOGICAL SERIES. imporknt of which form sphincters. By the contraction of the trunk muscles the water in the pharynx and atrial chamber is forcibly expelled from the atrial aperture, and the animal is in consequence propelled in an opposite direction. The muscle-fibres show a distinct transverse striation. Knoll, Deukschr. d. k. Akad. Wiss. Wien, Bd. Iviii. 1891, p. 671. C. 63. Apreparation of thetrunk muscles of AmpMowus lanceolatus. They consist of a series of open chevron-like muscle-plates (myotonies) arranged parallel to one another along the lateral parts of the body, with their apices directed forward and slightly above the mid-lateral line, those of opposite sides alternating. They are formed of longitudinal fibres, and are separated from one another and from those of the opposite side by a layer of connective tissue. They entirely surround the body with the exception of the ventral area of the atrial chambei-, where a layer of transverse muscle is interposed between their ventral ends. The fibres of which these nmscles are composed are trans- versely striated and have a highly characteristic plate-like form. The nucleus imbedded in a small quantity of un- differentiated protoplasm lies peripherally. There is no sarcolemma. The middle specimen shows the muscles in position after removal of the integument. On either side are several isolated myotomes showing their outer (on the right) and inner (left) surfaces. 0. C. 63 a. Langerhans, Arch. £. Mikr. Anat., Bd. xii. 1876, p. 291. VERTEBRATA. Form and Texture. Texture of Muscle. C.54. Portions of muscle from a Cod-fish (Gadus morrhaa), which have been steeped in an acid, and reflect iridescent colour in some lights, due to striation producing inter- ference. 0. C. 36. Hiinterian. MUSOULAtl AND ALLIED SYSTEMS. 103 C. 55. A portion of muscle from the neck of a Bull {Bos taurus) which has been boiled, and the connective tissue, vessels, and nerves removed from the lower part, and the muscular fasciculi unravelled. 0. G. 33. Hunterian. C. 56. A portion of a muscle which has been steeped in acetic acid, and the fasciculi separated into their constituent fibres. 0. 0. 33 A. Mus. Sir A. Cooper, Bart. C. 57. A portion of the gastrocnemius muscle, injected, dried, and put into oil of turpentine to show its vascularity. 0. 0. 35. Hunterian. C. 58. A portion of a simple muscle, injected, dried, and put into oil of turpentine, to show its vascularity and the mode of ramification of its minute vessels. 0. 0. 35 A. Mus. Sir Astley Cooper, Bart. C. 59. A portion of a semi-penniform muscle, similarly prepared for the same purpose. 0. C. 35 b. Mus. Sir Astley Cooper, Bart. C. 60. A portion of the diaphragm of a child, injected, dried, and put into oil of turpentine, to show the radiating disposition of the muscular fibres indicated by the blood-vessels. 0. C. 37. Hunterian. Texture of Tendon. C. 61. Portions of tendons from the leg of an Ostrich {Strut/do camelus), -which have in this animal an unusually brilliant lustre. 0. C. 47. Hunterian. C. 62. Part of a muscle and tendon from the leg of a Crane (Grus cinerea) , showing the method of insertion of the muscle-fibres into the superficial fan-shaped tendon. The tendon is sharply defined from the muscle-fibres and shows a strong tendency to ossification. 0. C. 64 Y s a. Presented hy W. B. Tegetmeier, Esq. C. 63. Section of one of the caudal tendon-bundles of a large Fin-whale {Baloanoptera musculus). 0. C. 45 E. 104 PHYSIOLOGICAL SERIES. C.64. A tendon from the leg of a Calf {Bos taurus), injected, driedj and put into oil of turpentine, to show its small degree of vascularity. 0. C. 49. Hicnterian. C. 65. The Human tendo Achillis, injected, with part of the gastrocnemius muscle, to show by contrast the diflFerence in the vascularity of these parts. 0. 0. 49 A. Presented by Sir William Blizard. Forms of Muscle. C. 66. A portion of the 'obliquus abdominis internus' of a Rhinoceros [Rhinoceros unicornis), showing the expanded form of tendon, termed 'aponeurosis.' 0. 0. 48 a. C. 67. A portion of the sartorius muscle of the Human subject to show the parallel straight direction of the umscular fibres. 0. C. 37 a. C. 68. A muscle — the ' biceps brachii ' of a Child, showing the aggregation of the fibres into two masses converging and uniting below into a single tendon of insertion, and forming a ' biceps ' muscle. 0. C. 45 A. Mus. tSi'r Astley Cooper, Bart. C. 69. A muscle — the ' extensor antebrachii ' of a Child, showing the arrangement of the fibres into three masses, united below into a single tendon of insertion, and forming a ' triceps ' muscle. 0. C. 45 b. Mus. Sir Astley Cooper, Bart. C. 70. A muscle— the chief extensor of the leg of a Child, showing the arrani£ement of the fibres into foui- masses which unite below to be inserted, by the intervention of the patelln, into the tibia. 0. C. 45 c. Mns. Sir Astley Cooper, Bart. C. 71. A portion of double penniform muscle from a Whale [lialmiioptera musculns?), showing this form of muscle and the coarseness of the muscular fasciculi. 0. C. 41 A. CUTANEOUS. 105 C. 72. A section of a muscle, consisting of a single series of oblique fibres, constituting the half-penniform muscle. Q Q 3g_ Hunterian. C. 73. A section of a muscle, consisting of a double series of oblique fibres, constituting the complete-penniform muscle. Q Q_ Hunterian. C. 74, A section of a pennif'orm muscle. 0. (!. 40. Hunterian. C. 75. A section of a penniforni muscle. 0. C. 41. Hunterian. C. 76. A transverse section of a complex muscle, to show the in- termixture of the muscular and tendinous fibres. 0. C. 44. Hunterian. C. 77. A section of a muscle, in which the fibres are disposed obliquely in several double series, with tendon intervening; constituting the complex muscle. 0. C. 42. Hunterian. C. 78. A longitudinal section of a complex or multi-penniform muscle. 0. C. 43. Hunterian. C. 79. A transverse section of a complex muscle. 0. C. 45. Hunterian. Regional. Cutaneous. lu all classes above Fish, the names attached to iudividual muscles are taken from lironn's Thier-reichs. An exceptii)ii has however been made in the case of the hind limbs of the Lizard (Nos. 0. 173 & C. 174), in which the names employed by Gadow (Morph. Jahrb. vii. 1882) have been substi- tuted to facilitate comparison with the Crocodile. C. 80. The skin of a Hedgehog (Erinaceus europmis) with the head, Hmbs, and tail, showing the powerful cutaneous muscles by the action of which the Hedgehog is rolled into a ball and completely enveloped and protected by the dorsal spine-bearing region of the skin . They can be conveniently separated into those concerned with (1) rolling, and (2) unrolling. The first group comprises the large orbicularis panniculi, a broad muscular band peculiar to the Hedgehog, 106 PHYSIOLOGICAL SERIES. closely adherent to the skin of the back along the bonier of the spine-bearing area, and a series of small muscles arising from the head, fore limbs, tail and ventral mid-line of the body, and inserted Into the inner margin of the orbi- cularis panniculi. These latter muscles draw the extremities together and at the same time drag the orbicularis panniculi so far towards the ventral surface that it can act like the running string in the mouth of a bag and cause the complete enclosure of the animal in the spine-bearing region of the skin. Unrolling is caused by the action of the longitudinal and transverse fibres of the dorsal region of the skin, with the help of certain small muscles arising from the skull and vertebral column, and so arranged that they draw the skin towards the middle of the back. 0. G. 64 z n. C. 81. Head and fore limbs together with the anterior half of the skin of a Hedgehog {Erinaceus eurojjceiin) , showing many of the cutaneous muscles in this region more clearly than in the previous specimen. 0. C. 64 z o. C. 82. Hind limbs and posterior half of the skin of a Hedoehoo- , too [Jinnaceus europceus), showing the cutaneous muscles. 0. 0. 64 z 2J. Himly, Ueber das Zusammenkngeln des Igels, Bruns- wick, 1801, p. 28. Dobson, Monograph of Insectivora, 1882, p. 41. Head and Neck. Ruge, Festschr. Gegenbaur, Bd. iii. 1896, p. 195. C. 83. Left half of the head and branchial region of a Doo-fish {Scyllium catulus), from which the skin has been removed to show the superficial muscles. These, with the exception of the large adductor mandibulae, are all derivatives of a common superficial circular layer (constrictor arcuum), the main function of which is to ex])el the water from the pharynx through the gill-openings. C. 84. Right half of the head and branchial region of the same Dog-fish showing the deeper branchial muscles. These HEAD AND NECK. 107 fall into three groups. 1. Interarcual muscles. 2. Adductors, serially homologous with the great mandibular adductor. 3. Ventral longitudinal muscles, these arise from the coracoid bar as a common mass and are inserted in pairs into the base of each visceral arch. Vetter, Jena. Zeitschr., Bd. viii. 1873-74, p. 405. C. 85. Head of a Haddock {Gadus ceglejinus), showing the super- ficial muscles of the left side. In this and other bony fish the muscles of the head are far more numerous and subdivided than in the Dog-fish, although their phylogenetic origin from similar simple muscle-sheets can be inferred with some degree of certainty. The specialization of the muscles is closely related to the greater number of skeletal parts and their increased mobility ; it is particularly apparent in the adductor of the jaw and in the opercular muscles. In all probability the opercular palatine and hyoid muscles represent the great superficial constrictor of the Selachian. Vetter, Jena. Zeitschr., Bd. xii. 1877-78, p. 489. C. 86. The muscles of the left branchial arches of a Haddock (Gadus ceylefinus). The muscles are highly specialized and provide for a great variety of movement, both of the individual arches and of the branchial skeleton as a whole. The dorsal muscles in particular, owing no doubt to their connection with the pharyngeal toothed pad formed by the hypopharyngeal bones, show a high degree of complexity and can produce movements in anterior, posterior, dorsal and lateral directions. C. 87. Head of a Python {Python sebai), showing the chief muscles. They fall into three groups. 1. Those concerned in the movements of the lower jaw, consisting of parieto- quadrato-mandibularis, analogous in function to the temporal and masseter of mammals ; occipito-quadrato-mandibularis, analogous to the depressor maxillae inferioris (digastric); transverso-maxillo-pterygoideo-mandibularis, analogous to the external pterygoid; and a curious pair of muscles (intermaxillares) that pass diagonally across the floor of the mouth from either mandibular joint to the anterior end of the 108 PHYSIOLOGICAL SERtRS. opposif,e mandible ; they check excessive divarication of the mandibular rami. 2. Those concerned with the movement of the palate— the pterygo-sphenoidalis posterior and anterior tor the approximation of the posterior and anterior ends respectively of the pterygoids, and a levator of the pterygoid (pterygo-parietalis). 8. A retractor of the vomer Tvomer sphenoideus). D' Alton, Arch. f. Anat., 1^34, p. 348; Duges, Ann. 8ci. Nat., t. xii. 1827, p. 337. C. 88. Head and neck of a Rook {Trypanocom.v fruyilegus), in which the tongue and pharynx have been displaced to show the muscles of the jaws and hyoid. Tiiey are few and simple. The jaw is depressed by a single-bellied muscle, very similar in its position and general appearance to the' de]jressor of Ornithorhynchus shown in Xo. ( 9;). It i< possibly homologous to the posterior belly of the manimalian depressor. The beak is closed by a double temporalis and a well-developed pterygoid. The geniohyoid is the most important muscle connected with the hyoid apparatus, it passes backwards from the lower jaw and is wound round the apex of the hyoid cornu — it i)rotrudes the tongue. Retraction is caused by the styloglossus. 0. C. 04 y //. Shufeldt, Myology of the Raven, London, 18^0, p. 15. Presented hy St. George Mivart, Esq. C. 89. Head and anterior part of the sternum of a Uape Hyrax {Procavia [Hyra,e\ cape/isis), showing certain muscles of the neck. From the upper ascending ramus of the jaw on either side there arises a voluminous muscle, whose fibres pass downwards and backwards — some of them are inserted upon the manubrium sterni, but the majority meet those of the corresi)onding muscle of the opposite side in a median raphe. The function and homologies of this muscle are obscure, but it possibly represents a migrated portion (sterno-maxillary) of the sterno-mastoid, such as occurs in the Horse and other Ungulates. Its presence gives the well-known puffy appearance to the neck of the Hvrax. George, Ann. Sci. Nut., ser. 6, t. i. 1874, p. 102. HEAP ANP NECK. 109 C. 90. Portion of the liyoid bone o£ a Horse [Eguus caballns), showino- the hyoideus hitns passing between the posterior cornu and the ceratohyal on eitlier side, and a mnscuhir band (hyoideus transversus) that unites the upper ends of the ceratohyals over the base of the tongue. Presented hy Prof. MrFadyean, C. 91. Anterior portion of the lower jaw of a Seal {Plioca vitidina) showing the muscles of the intermandibular space. The mylohyoid is divided into two parts. The one situated 25 mm. behind the symphysis passes directly from one mandible to the other, and has much the characters of the transversus mandibulre of Rodents. The second portion lies posterior and slightly dorsal to the first, its fibres pass obliquely forwards towards the mid-line, and there unite in a median raphe. The space in front of the mylohyoid is occupied by the anterior part of the geniohyoid. C. 92. Hyoidbone and epiglottis of a T>o^ (Canu familians) , showing a well developed hyo-epiglottidean muscle. It arises by a separate head from the lower end of each cerato- hyal ; both heads pass backwards and upwards, unite, and are inserted in common upon the anterior surface of the epiglottis. 0. C. 64 z q. Presented by Prof. McFadyean. C. 93. Head, thorax, and proximal part of the fore limbs of a Lemur [Lemur mongoz), showing the superficial muscles on the left, the deep on the right. The following points may be noted : — (On the Left side). The division of the deltoid into three parts is very distinct The two heads of the biceps are almost entirely separate, being only slightly joined towards their distal end. This condition is more usually found in Galago than in Leinur.— {On the Right side). The cleido- mastoid is independent of the sterno-mastoid. The omo- hyoid has no tendinous intersection. The depressor maxilhe inferioris (digastric) is strongly digastric, a slender tendon (indicated by black bristles) passes from its inner border to the mylohyoid.. 0. C. 64 m bf. Presented by Prof. F. G. Parsons. Murie & Mivart, Trans, /ool. Soc, vol. vii. 1872, p. 12. 110 PHYSIOLOGICAL SERIES. C. 94. Head of Orang-Ontang {Simia satyrus) with the skin removed from the left lialf to expose the superficial muscles. These are well developed upon the face, more especially in the protuberant mobile lips. They are extremely variable in the details of their arrangement, and their boundaries are very indistinct. This group of muscles is derived from the platysma myoides and sphincter colli, it is su])plied by the 7th nerve, and can probably with safety be referred to the hyoid portion of the sujierficial constrictor of the Selachian. 0. C. 64 M c. Presented hy C. Dent, Esq. Euge, Untersuchungen iiber die Gesichtsmuskulatur der Primaten, Leipzig, 1887, p. 2. Depressor maxillae inferioris (Digastric). Dobson, Trans. Linn. Soc, vol. ii. 1882, p. 259 ; Parsons, Jour. Anat. & Physiol., vol. xxxii. 1898, p. 436. C. 95. Part of the skull of Ornithorhynchus anatinus, showing the masseter and depressor maxillae inferioris (digastric) muscles. The depressor rises from the posterior border of the glenoid cavity and is attached to the ventral surface of the hinder part of the mandible. It is doubtful whether this muscle is homologous with the depressor of other mammals, in spite of its somewhat analogous position and action. C. 96. Skull of Potorovs [Ilypstprymnttsi tridactylns, with the depressor maxillte inferioris (digastric) and mylohyoid muscles. The depressor is indistinctly digastric, the anterior and posterior bellies being separated from one another by a slight constriction and tendinous intersection. A few tendinous fibres pass from the intersection to the posterior margin of the mylohyoid. The anterior belly is attached to the mandible near the symphysis. C. 97. Head of a young Three-toed Sloth {Bradyjms tridactylvs)' showing the chief muscles of mastication. The two bellies of the depressor maxillae inferioris (digastric) are separated DIGASTRIC. Ill by a weak tendinous intersection. The intersections of opposite sides are united by a subbyoidean tendinous arcade, wbicb forms a base of origin for the anterior bellies. The latter occupy the whole of the intermandibular space. C. 98. Skull of a Mole (Talpa europcea), showing the depressor maxill?e inferioris (digastiic) muscles. They are of the monogastric type, interrupted on a level with the angle of the jaw by an extremely feeble tendinous intersection ; they arise from the paroccipital region of the skull by a largej fleshy origin and gradually taper to a fine tendon attached to the middle of the mandible, and also by a few fibres to the posterior margin of the mylohyoid. C. 99. Skull of Galeopithecus volans with depressor maxillae inferioris (digastric) and mylohyoid muscles. The depressors are monogastric with a feeble tendinous inter- section. They are attached to the angles of the jaw. The anterior part of the mylohyoid is intimately bound to the geniohyoideus. C. 100. Occiput and lower jaw of a Hare [Lepns europcieus), showing the depressor maxillce inferioris (digastric) muscles. In this family of Rodents the depressor is monogastric, represented by the anterior belly alone ; the place of the posterior belly is occupied by a long tendon attached to the paroccipital process. 0. C. 64 z Z h. Parsons, Jour. Anat. & Phys., vol. xxxii. 1898, p. 441. C. 101. Head of a Guinea-pig {Cavia porcellus), showing the mas- seter and depressor maxillae inferioris (digastric) muscles. The anterior and posterior bellies of the depressors are separated from one another by a slightly constricted area the surface of which is tendinous. The anterior bellies are attached near the symphysis at either end of the trans- versus mandibulse. 0. C. 64 z I c. Parsons, Jour. Anat. & Phys., vol. xxxii. 1898, p. 489. C. 102. Skull of Dasyprocta ayuti, with depressor maxillfe inferioris (digastric), mylohyoid, and hyo-epiglottidean 112 PHYSIOLOGICAL SERIES. muscles. Tlio two bellies of the depressor are separated, as in the Guinea-i)ig, b}' a constri(;tioii and superficial central tendon. A fine tendon connects the latter with the posterior margin of tlie mylohyoid. Tiie interinandibular space close behind the symphysis is occupied by an inde- pendent portion of the mylohyoid (transversus mandilmhe; : its contraction divaricates the lower incisors. C. 103. Head of a Fox-Squirrel {'Sciurus hidoririanii.s), showing, from the ventral aspect, the depressor maxillae inferioris (digastric) muscles. They are stronglv digastric ; the central tendons have an attachment to the hyoid, and by union with one another in the mid-line form a siib-liyoidean tendinous arch, from the anterior margin of which the anterior bellies arise. The latter are closely contiguous and occupy the median third of the intermandibular space. They are inserted at the symphysis menti. 0. C. 64 z I a. Parsons, Jour. Anat. & Phys., vol. xxxii. 1898, p. 438. C. 104. Part of the skull and hyoid bone of a Colt {Eqiui.i cahallus) showing the depressor maxilla? inferioris (digas- tric) and stylohyoid muscles. The depressor is strongly digastric ; its long central tendon perforates the tendon of attachment of the stylohyoid. A large part of its posterior belly is attached directly to the inner surface of the angle of the mandible. The stylohyoid is divided into two portions by the posterior process of the stylohyal. The proximal part (mastoideo-styloideus) — regarded by some as part of the depressor — passes from the paroccipital process to the stylohyal. The distal part rises by a slender tendon from the outer surface of the posterior process of the stylohyal. Presented by Prof. McFadyean. C. 105. Occiput, hyoid, and lower jaw of a Sheep {Ovis avies), showing the depressor maxilla? inferioris (digastric), stylo- hyoid, mylohyoid, and hyo-epiglottidean muscles. The depressor is a strongly digastric muscle with its anterior belly attached far back upon the inner surface of the mandible and partly also into the rajdohyoid. The mas- toideo-styloideus is fan-shaped ; the stylohyoideus rises DIGASTRIC. 113 from the apex of the posterior process of the stylohyal ; it runs over the outer surface of the depressor and is attached to the body of the hyoid. C. 106. Occiput and hyoid bone of a Calf (Bos taurus), showing the depressor maxillae inferioris (digastric) and stylohyoid muscles. The mastoideo-styloideus portion of the stylohyoid is more developed than in the Sheep and extends for a considerable way down the inner surface of the stylohyal. C. 107. Skull of a foetal Seal (Phoca viiulina), showing the monogastric depressor maxillae infeiioris (digastric). The anterior part of the left depressor shows signs of longi- tudinal division. There is no tendinous intersection. Miller, Challenger Reports (Zool.), vol. xxvi. 1888, p. 215. C. 108. Head of a young Otter {Lutra lutra) with mastoideo- styloideus, styloglossus, and parts of the depressor maxillae inferioris muscles. The depressor (most of which has been removed) is monogastric. The stylohyoid is represented by its mastoideo-styloidean portion only. C. 109. Lower jaw of a Dog [Canis familiaris) , showing the depressor maxilla3 inferioris (digastric), mylohyoid, and stylohyoid muscles. The depressor is of the monogastric type, but sometimes — as in this specimen — shows a very delicate tendinous intersection on a level with the angle of the jaw. It Ls attiiched to the mandible near its middle. The stylohyoid muscles are very slender, that on the right sends a slip to the depressor, while the main part of the muscle vanishes before reaching the hyoid. Presented by Prof. McFadyean, Ellenberger & Baum, Anat. des Hundes, Berlin, 1891, p. 131. C. 110. Occiput and lower jaw of a Crested Baboon {Cynoioithe- cus niger), dissected to show the depressor maxilla3 inferioris (digastric) muscles. The po.sterior belly on each side terminates anteriorly in ii long central tendon, which unites with its fellow of the opposite side to form a tendinous 114 PHYSIOLOGICAL SERIES. subhyoid arch. The anterior bellies arise from the anterior margin of the arch and radiate from it as a single sheet to the mandibles. 0. C. 64 M & c. Parsons, Jour. Anat. & Phys., vol. xxxii. 1898, p. 438. C. 111. Left half of the head of an Orang-Outang {Simia saty- rus), seen from the basal aspect. The depressor maxillae inferioris (digastric) is represented only by the posterior belly. It is inserted by tendon upon the inner surface of the angle of the jaw. In many individuals traces of the anterior belly have been observed. 0. C. 64 M c a. C. 112. Depressor maxillse inferioris (digastric) muscles of a Chimpanzee {Antliropopitliecus troglodytes). The general arrangement is very similar to Cynopithecus (C. 110). The central tendon perforates the tendon of attachment of the stylohyoid. 0. C. 64 M c b. Trunk. C. 113. Transverse section through the caudal region of a Dog- fish (^Scyllium catulus). In consequence of the complicated course and shape of each myotome, a large number of them are cut through in a single section. The concentric rings upon the section surface are the result of a series of hollow conical projections from the anterior face of each myotome, lying one within another and separated from each other by the intermuscular septa of fibrous tissue. O.C. 63 b. C, 114. Part of the vertebral column of a Mackerel (Scomber scomber), with a single myotome attached to the left side. The fibres of the myotome run longitudinally, attached by either end to a fibrous intermuscular septum that traverses the body in a dorso-ventral direction and is attached to vertebral column and superficial trunk-fascia in the form of a W with the base directed backwards. The median part of the myotome (i. e. the middle bend of the W) is pro- longed forwards, above and below the mid-lateral line to TRUNK. 115 form a pair of hollow cones, which fit accurately into the cavity of the two similar coues of the myotome in front and are themselves filled by those of the myotome behind. Between and superficial to the bases of the cones there is a wedge of soft muscle of a dark reddish-brown colour. 0. 0. D a. C. 115. Transverse section through the body of a Mackerel {Scomber scomber), showing the concentric rings due to the section of muscle-cones of successive myotomes and the division of the trunk-muscles into dorsal and ventral columns by a longitudinal lateral septum. The brown superficial lateral muscle in this specimen has assumed a lighter tone than the general trunk-muscles. The pattern formed by the cut edges of the intermuscular septa is here far simpler than in the Dog-fish, and indicates a less com- plicated form of myotome. 0. C. 63 D h. C. 116. A portion of the trunk of a Python [Python sebce), dissected from the left side to show the musculature external to the ribs. A lateral cutaneous muscle (cutaneusexternus), composed of numerous ribbon-like strands, arises high up on each rib and passes downwards and backwards to the skin. It is opposed by the cutaneus internus, arising in separate fasciculi from the point of each rib and passing forwards to the ventral parts of the skin. On either side of the back there is a large composite mass of muscle, which forms a specially strong and important feature in the muscular system of the constricting serpents, its chief components are the capito-vertebralis and the retractor cost£e biceps. Beneath the strands of the cutaneus externus lies a sheet of muscle composed of intercostal es superiores and inferiores, posteriorly they have been separated to show their attach- ments. Each fasciculus of these muscles passes over from 12-10 ribs between its origin and insertion. In the lower part of the specimen the intcrcostales proprii are visible, passing from rib to rib. 0. C. 63 I. D' Alton, Arch. f. Anat. 1834, p. 432. I2 116 PHYSIOLOGICAL SERIES. C. 117. The right half of a portion of the trunk of a Python {PytJwn sehcn) seen from within; to show the internal rib-muscles. Dorsal to the origin of the abdominal muscles, there are two costal retractors ; of these two the internal (M. costo-vertebralis superior) is the most strongly developed! Its fasciculi arise from the hypapophyses of the vertebra, and passing forward over 6 ribs are inserted in the seventh. The last three ribs in this specimen have been stripped, leaving only the costo-vertebralis inferior at their base ; this is a small muscle for the protraction of the ribs O.C. 63l. C. 118. Ventral body-wall and ends of the ribs of a Python (P . sehce) seen from above, showing the abdominal and lower internal costal muscles. The abdominal muscle (composed of two sheets inti- mately connected together) arises from the middle of each rib and passes diagonally across the body direct to the ventral middle line, where it is inserted in a strong apo- neurosis. It tends to flatten the body during locomotion. The left half of this muscle has been retained, the right cut away, to show the ventral shield muscles and the cutaneus internus passing forward from the ribs to the skin. Two internal costal retractor muscles are shown on the right side^ the one (retrahens costarum brevis) takes a longi- tudinal course between the points of the ribs ; the other (retrahens costarum longus) arises beneath the origin of the abdominal muscle and is inserted on the 5th rib in front, 6 mm. from the point. 0. C. 63. K. C. 119. Transverse section through the body of a Python [Python sehce), showing the position and double nature of the abdominal muscle-sheet. 0. C. 63 n. C. 120. A portion of the ventral body-wall of a Python (P. sehce) seen from above, showing the ventral shield muscles. The most conspicuous cf these are the interscutales majores. They take their origin from the middle of the antei'ior edge of the ventral shields and pass outwards and backwards to FORE-LIMB. 117 their insertion on the side scales 2 or 3 rows behind ; they tend to erect the free edge of the ventral shields. Superficial to these muscles lie a series of more or less longitudinal muscles passing from shield to shield, they drag the scales individually forward, sliding one over the other. This action brings the free edges of the shields flat against the body. 0. C. 63 m. C. 121. Posterior extremity of the tail of a Spider Monkey (Ateles sp.). The skin has been removed from the dorsal surface to show the mode of attachment of the tendons to the ventral skin. 0. C. 64 M 5 6. Fore-limb. C. 122. Right pectoral fin of a Dog-fish {Scyllium catulus). Several fairly disiinct off-shoots from the trunk-muscles enter into direct relations with the shoulder-girdle and fore- shadow the trapezius, latissimus dorsi, and pectoral muscles of higher veteb rates. The limb-muscles are in the form of simple dorsal and ventral sheets, separable towards the base of the fin into superficial and deep layers, both are inserted into the horny fin-rays. The transition from trunk- to limb-muscles is well shown. Humphry, Jour. Anat. & Physiol., vol. vi. 1872, p. 271. C. 123. Longitudinal section through the left pectoral fin of a Dog-fish {Scyllium catulus), showing the arrangement of deep (basio-radial) and superficial layers of muscle on either surface of the fin. C. 124. Eight pectoral fin of a Sea-Cat {Chimara monstrosa). The muscles in connection with the shoulder-girdle are more numerous and show greater individuality than in the Dog- fish. Those proper to the fin are still comparatively simple — the superficial and deep layers being clearly defined only on the ventral aspect. Upon the dorsal surface the general muscle-mass, owing to the normally rotated position of the fin, is so folded upon itself that its posterior part runs diagon- ally from the base of the scapula to the posterior margin of 118 PHYSIOLOGICAL SERIES. the fin, and is thus able to produce the rotary movements so important in swimming. The fin as a whole can be protracted and retracted by the latero-scapularis and coraco- basalis. C. 125. Right pectoral fin of a Cod [Gadus morrhua), showing the muscles. Deep and superficial layers can be recognized on both surfaces of the fin, in the form of well-defined muscles which cross one another at an acute angle. A small muscle (dilator) is situated along the anterior border of the fin and inserted on the base of the anterior fin-ray. C. 126. Right pectoral fin of Periophthalmus koelreuteri. The muscles upon the dorsal (inner) surface of the fin are greatly developed, probably in connection with the land- walking habits of the fish— and extend for a considerable distance down the fin-rays. Hammerle, Bericht. d. Naturforsch. Gesell. Freiburcr, Bd. X. 1897, p. 20. C. 127. Fore limbs of a Hell-bender {CryptohrancJius alleglian- iensis), showing in the upper specimen the superficial, and in the lower the deep muscles. As in other Urodeles the limb movements are of a very generalized nature without any great precision. The muscles are accordingly simple in their arrangement and mostly have the form of broad sheets. The coraco- brachial muscles are strongly de- veloped, as in the Reptiles, but as yet there is no repre- sentative of the biceps unless perhaps the coraco-radialis proprius may be so regarded. The dorso-humeralis gives origin to a very large and extensive dorso-epitrochlearis (anconeus scapulae medius), and is itself in part continued to the humerus upon the outer surface of the arm — a course that suggests the condition of the latero-scapularis in the Dog-fish. The superficial extensor and flexor sheets of the fore-arm are each divided into three seg- ments. The median of these is attached to the fingers, and the lateral to the radius and ulna respectively. The deep layer is chiefly confined to the hand and distal part of the fore-arm. The following is a list of the muscles, FOUE-LIMB. 119 indicated by numbers and capital letters. 1. Capiti dorso- scapiilaris. 2. Basi-scapularis. 3. Thoraci-scapularis. 4. Pectori scapiilaris internus. 5. Pectoralis. 6. Supra- coracoidens, similar to the supracoracoidens of Reptiles, Birds, and Monotremes. 7. Goraco-bracbialis longus. 7^. Coraco-brachitais brevis. Attached to tbe inner border of tbe coraco-bracbialis longus is a fine tendon — coraco-radialis proprius— which is considered by some to represent tbe biceps, but is more likely a purely Amphibian muscle. 8. Humero-antebrachialis inferior. 9. Pro- coraco-humeralis. 10. Dorso-humeralis. 11. Dorsalis scapulse. 12. Anconeus. A. Humero-radialis volaris. B. Humero-phalangei volares li-v. C. Humero-ulnaris volaris. The distal fibres of this muscle are continued along the border of the little finger and form an abductor minimi digiti (humero-metacarpus v. dig. volaris). D. Ulnari- metacarpi volares. E. Humero-radialis dorsalis. F. Hu- mero-digiti li-v. dorsalis. G. Humero-ulnaris dorsalis. H. Ulnari-phalanx ii: dorsalis. I. Carpo-phalangei. Be- tween the toes are well-developed interossei. Mivart, Proc. Zool. Soc. 1869, p. 264. C. 128. Left fore-limb of a Bull-Frog {Rana catesUana), showing that the tendon of the anconeus is thickened as it passes over the elbow-joint ; that it plays on a convexity at the lower and back part of the humerus, and acts as a substitute for the olecranon. O.C. 276 b. C. 129. Left fore-limb of a Surinam Toad {Pipa americana), showing a sesamoid bone interposed like a patella between the tendon of the anconeus and the elbow-joint. 0. C. 276 c. C. 130. Left fore-limb of a Lizard {Varanus salvator), showing the superficial muscles. The muscles, as might be expected from the active and accurate movements of the limbs, are far more numerous and specialized than in the Urodele ; they are in most cases powerful, but show no special con- centration of strength in any particular region of the limb. The following may bo noted :— The supracoracoidens ; a 120 PHYSIOLOGICAL SERIES. nmscle that in the ascending series is last met with in the Monotremes (see No. G. 139). Coraco-antebrachialis (biceps) : both heads rise from the coracoid and unite near their insertion ; the outer one is digastric, with a central tendon where the muscle crosses the shoulder-joint ; the muscle is inserted, as in many lower mammals, into both'ulna and radius. The coraco-brachialis : divided into two parts, both of great size. The humero-antebrachialis inferior unites with the coraco-antebrachialis before its insertion. The anconeus rises by four heads, respectively scapular, coracoidal, and humeral (two) in their origin ; the coracoid head is to a large extent represented by tendon. The carpo-digitalis ventralis brevis (flexor sublimis digitorum) is entirely confined to the hand and takes origin from the annular ligament. The teres major is absent. 0. C. 64 y t. C. 131. Right fore-limb of a Lizard ( Varanus salvator), showing the deeper muscles. An accessory pronator (ulno-carpaHs*) is present, crossing the arm from the inner and anterior surface of the internal condyle to the radius above the insertion of the epitrochleo-radialis (pronator teres) ; it probably forms part of the uhio-radialis (pronator quad- ratus). 0. C. 64 YM. Fiirbringer, Morph. Jahrb., Bd. i. 1876, p. 688 ; Mivart, Proc. Zool. Soc. 1867, p. 775. C. 132. The nerves and superficial muscles of the right fore-limb of a Crocodile {Crocodilus acutus). While the musculature in general is weaker than that of the Lizard, there is a marked preponderance in strength of the muscles of the shoulder and upper arm over those of the fore-arm. The muscles most developed are those concerned in the dorso-ventral movements of the shoulder (dorsalis scapulae [deltoid] and pectoralis) and in the extension of the elbow (anconeus), movements of considerable importance to the Crocodile in balancing and steering through the water. The following comparisons may be made with Varanus : — The dorsalis scapulae (deltoid) is double. The coraco- antebrachialis (biceps) has only one head. The coraco- brachialis longus is absent. Between the humero-ante- rORE-LIMB. 121 bracliialis inferior (bracliialis aniicus) and outer humeral head of the anconeus is a muocle (humoro-radialis) that passes from the kiteral tubercle of the humerus to the radius ; it probably represents part of the deltoid. The humero-radialis lateralis (flexor carpi ulnaris) is single. The carpo-digi talis ventralis brevis is confined to the hand. O.C. 63 E. C. 133. The nerves and deep muscles of the left fore-limb of a Crocodile {Crocodilus acutus). There is no ulno-carpalis (accessory pronator). The teres major is well developed. 0. C. 63 F. Furbringer, Morph. Jahrb., Bd. i. 1876^ p. 767. C. 134. Part of the sternum, shoulder-girdle, and left wing of a King Vulture {Cathartes papa), showing the muscles. The pectoralis is separable into two distinct portions. The larger of the two (mostly removed in the specimen) is superficial in position ; it rises from the posterior part of the body of the sternum, the border of the sternal keel, and the clavicle, and is attached to the radial crest of the humerus. The second part (which has been slightly raised to show the supracoracoideus beneath it) rises from the sternal keel and clavicle beneath the first, its fibres rapidly converge to a narrow flat tendon which is attached to the humerus distal to the first part. The pars extensor secund- ariorum of the metapatagealis is well marked : this muscle, situated beneath the skin of the elbow, spreads the proximal secondaries ; it is remarkable for the length and delicacy of its tendon of origin. The deltoid extends little more than halfway down the humerus. 0. C. 64 Y h. C. 135. Right wing and half the trunk of a Rook {Trypanocorax frugilegus), showing the muscles. During flight the wing is mainly moved as a whole from the shoulder ; its primary movements are depression and elevation, constituting re- spectively the essential parts of the stroke and recovery. The down stroke is produced by the pectoralis major, a muscle that occupies the greater part of the cavity between the surface and keel of the sternum ; elevation is due to a 122 PHYSIOLOGICAL SRRIES. smaller muscle (supracoracoideus) that arises from the sternum beneath the pectoralis major, passes as a tendon over the point of the shoulder to its dorsal surface in a canal formed by the union of the three bones of the shoulder-girdle, and is finally attached to the humerus proximal to the radial crest. The recovery is also probably to a great extent assisted by the pressure of air due to the momentum of the bird. During the down stroke the wing is usually fully extended, but in the recovery the wrist and elbow are flexed, the patagium at the same time being contracted by the propatagealis and a system of elastic ligaments in connection with it. The wing is also capable of extensive rotation at the shoulder, whereby the angle made by its surface to the horizon can be adapted with great nicety to the most varying conditions. The tendons of the fore-arm and hand are remarkably long and slender, while all the heavier and more important muscles are con- centrated upon the body or near the shoulder. By this means the wing is rendered light and manageable, and at the same time the centre of gravity of the bird is lowered. Note should be taken of the muscles of the hand, which are quite rudimentary, and of the propatagealis muscles. The latter are represented b}^ two muscular slips that rise together from the dorsal end of the clavicle and are inserted by long tendons into the wrist, extensor metacarpi ulnaris, and the surface of the patagium ; the tendon of the anterior of the two muscles consists mainly of elastic tissue. Some- what analogous patagial muscles are found in certain flying mammals. 0. C. 64 y o. Presented hy St. George Mivart, Esq. Shufeldt, Myology of the Raven (London, 1890), p. 66. C. 136. Right wing of a Rook [Trypanocorax frvgilegus), s\\o\\'mg the deep muscles. Attention is drawn to the following : — The biceps, a single muscle, rising by two tendinous heads from the coracoid and humerus respectively ; it is inserted on the ulna. The deltoid is double and attached to the outer surface of the humerus as far as the external condyle. The entepicondylo-radiales : two powerful pronators of the fore-arm. The supinator (ectepicondylo-radialis) is TTORE-LIMB, 123 weak. The extensor metacarpi vadialis is so attached to the humerus and base of the thumb that upon extension of the elbow it is tightened, and is capable, without any contraction of its own, of fully extending the hand. 0. C. 64 Yjo. Presented ly St. George Mivart, Esq. C. 137. Eight shoulder of a Rook ( Trypanocorax frugilegus), showing in njore detail than in the previous specimens the levator (supracoracoideus) and rotator muscles of the humerus. A green rod has been placed beneath the supra- coracoideus to show its tendon entering the canal between the bones of the shoulder-girdle. The distal part of its tendon can be seen below the deltoideus minor. 0. 0. 64 Y q. Presented hy St. George Mivart, Esq. C. 138. Eight wing of a Wild Duck {Anas hoscas) from which the skin of the ventral surface has been removed to show two elastic ligaments. The most important of these (indicated by black paper) is situated along the free border of the propatagium, and represents in a modified form the tendon of the propatagealis muscle. The elastic tissue appeai-s abruptly in the tendon 10 mm. from the muscle, and is attached partly to the distal end of the radius, partly by means of a long inelastic tendon to the base of the thumb. In action it tends to flex the elbow during the recovery, and at the same time tightens the patagium. The other elastic ligament runs along the iilnar margin of the wing and is attached to the quill of each of the remiges; at the elbow it passes into a diffuse layer of subdermal elastic tissue con- nected with the metapatagealis muscle. In this hgament the elastic tissue is mainly present between the feathers, which are by its means drawn together when the arm is flexed. Fiirbringer, Anatomic der Vogeln, 1888, p, 583. C. 139. Eight fore-limb of a Spiny Anteater {Tacliyglossus [ Echidna'] aculeata), showing the superficial muscles. This limb, both in its musculature and general features, affords an excellent example of the peculiarities associated with digging habits. It is remarkably short and thick-set, and^ while all 124 PHYSIOLOGICAL SERIES. the muscles are ^velI developed, those brought into play during the backward scratching movements (latissimus dorsi, extensor antebrachii, flexor digitorum) are exception- ally powerful. Apart from the intrinsic strength of these muscles, the efficiency of the latissimus dorsi is largely increased by its direct insertion upon the internal condyle of the humerus. The large size of the pronator teres, in comparison with the supinators, may perhaps be accounted for by another digging movement, ?. e. the turning out- wards of the palm of the hand to throw the dirt clear of the body. Besides these features connected specially with the action of the limb, the following muscles are of great interest owing to their strongly reptilian characters :— The supracoracoideus (found among mammals only in the Monotremes). The biceps with no scapular origin. The coraco-brachialis longus and brevis, two large muscles with striking reptilian features {No. C. 130). The extensor carpi radialis longior inserted upon the scapho-lunar (the usual reptilian insertion). Attention is also drawn to the following peculiarities :— The latissimus dorsi is double, one head originating from the dorsal vertebrae (cut short in the specimen), the other from the posterior angle of the sca- pula. Owing to the outward rotation of the anterior border of the scapula, the origin of the supraspinatus has been shifted to its ventral surface and that of the subscapularis to the dorsal. There is a distinct epicoraco-brachialis. The flexor digitorum (probably answering to both flexor subhmis and profundus) forms a single fleshy mass from which at the wrist five stout tendons are given off" to the fingers. The palmaris longus is absent. 0. C. 64 z. C. 140. The deep muscles of the left fore-limb of a Spiny Ant- eater ( Tacliyglossus [EcJiidnd] acxdeata). 0. C. 64 z a. Westling, Bihang Svenska Vet.-Akad. Haudlingar, Stockholm, Bd. xv. 1889, p. 12. C. 141. The right fore-limb of a Duck-billed Platypus (Ornitho- rhynclms anaiinus), showing more especially the muscles of the fore-arm and hand. In the main they agree with those of Ecliidna. The insertion of the pronator teres is, however, to the middle of the radius, and there is a distinct FORE-LIMB. 125 though small flexor sublimis. It is confined entirely to the hand, as in reptiles, and consists of four small bellies that rise at the level of the wrist from the common deep flexor tendon, and are inserted lower down into the sheaths of the four inner deep tendons. Coues, Commun. Essex Inst., vol. vi. 1871, p. 151. C. 142. Superficial muscles of the right fore-limb of a Wallaby {Macropus ruficollis) . The musculatiire, in conformity with the somewhat rudimentary nature of the limb, is of a very feeble description, especially in the fore-arm and hand. The most powerful group of muscles are the extensors of the elbow. The following features are of interest : — The deltoid is single. There is a very strong connection (" achselbogen ") between the latissimus dorsi and pecto- ralis, indicating the original continuity of these muscles (see No. 0. 122). The coraco-brachialis brevis, as in all Kangaroos, is alone present. The biceps originates by a single head from the coracoid^ passes superficial to the shoulder-joint, and divides during the latter part of its course into two distinct bellies, attached respectively to ulna and radius. The supinator longus is attached to the carpus. 0. C. 64 z d. C. 143. Left fore-limb of a Wallaby (Macropus ruficollis) showing the deeper muscles. The flexor sublimis rises about the middle of the forearm from the surface of the flexor pro- fundus. O.C. 64ze. Parsons, Jour. Anat. & Physiol., vol. xxxii. 1898, p. 125. C. 144. Left fore-limb of a Koala (Phascolarctus cinereus), show- ing the coraco-brachialis, brachialis internus, and biceps muscles. All three varieties (longus, medius, and brevis) of the coraco-brachialis are present. The insertion of the medius and longus occupies the entire distal half of the inner side of the humei'us. The coraco-radial and gleno- ulnar portions of the biceps, as in many Marsupials, are quite separate from one another ; the tendon of the long head lies outside the capsule of the shoulder-joint. 0. C. 64 z ^ a. Presented by Prof. G. B. Howes, 126 PHYSIOLOGICAL SERIES. C. 145. Muscles and nerves of the right fore-limb of a Great Anteater {Myrmecophaga Juhata). The limb is mainly used for digging, and is remarkable for the great size and strength of the extensors of the elbow and of the flexor digitorum. The latter muscle, in particular, is enormous ajid nearly equals in bulk all the rest of the fore-arm muscles put together. It will be noticed that there is no indication of specially powerful movements of the shoulder such as are found in Echidna (No. 0. 139), and probably a larger share of the work is done by the flexion of the fingers. The following peculiarities should be noted : — The extensor antebrachii is assisted in its action by a very powerful dorso-epitrochlearis on the inner side of the arm. The subscapularis is intersected by ten tendinous planes, and is perforated by the short head of the biceps (in the Sloth the subscapularis is completely double.) The biceps is inserted both into the radius and (in conjunction with the brachialis internus) into the ulna. The epitrochleo- anconeus, as in most other Edentates, is remarkably power- ful. The supinator longus is divided into two parts, one of which has the usual characters, the other is inserted into the fascia coveiing the flexor surface of the fore-arm. The extensor carpi radialis longus is absent. The flexor carpi ulnaris is double. 0. C. 64 z ^ c. Pouchet, Memoires sur le Grand Fourmilier, 1867, p. 5 ; Windle & Parsons, Proc. Zool. Soc. 1899, p. 314. C. 146. The right fore-limb of a Three-toed Sloth {Bradypus tridadylns), showing the muscles. In this Edentate, which spends its life suspended by its hook-like claws from the branches of trees, the extensor muscles are feebly de- veloped throughout the arm, but the pectoral muscles and flexors are very powerful. The biceps is remarkable. It coiLsists o£ three parts :—(l) Along ribbon-like strip arising from the region of the coracoid in close connection with the deltoid and inserted partly into biceps in. and partly into the fascia on the flexor surface of the fore arm ; it passes superficial to the pectoralis major. (2) The long head arises by tendon from the base of the coracoid, per- forates the origin of biceps Ui., and is inserted ijjto the FORE-LIMB. 127 ixlna. (3) The short head arises from tlie humerus on a level with the pectoralis insertion, and is inserted on the radius. The flexion of the elbow is probably to a great extent helped by the supinator longus and pronator teres. The former muscle is in two parts, and arises from the whole length of the humerus distal to the deltoid. The flexor digitorum has a common belly which gives off a powerful tendon to each of the digits. Windle & Parsons, Proc. Zool. Soc. 1899, p. 314. C. 147. Muscles of the left fore-limb of a Manatee {TricJiechus manatus). Locomotion is entirely due to the powerful spatulate tail, the fore-limbs being mainly used for balan- cing and steering, and also to a limited extent for clasping the seaweed when browsing. The muscles, besides showing many peculiarities in detail, are remarkable for the great development of those connected with the fingers. In con- sequence the hand has greater freedom of movement than its external appearance would suggest, and affords in this particular a striking contrast to the flipper of the Cetacea. The following muscles should be noticed : — The cephalo- humeral (cleido-occipitalis) , originating from the occiput and inserted on the humerus between the deltoid and pectoralis major (its insertion only is shown). The biceps is in a much reduced condition ; it consists of two separate heads — one of fair size rising from the coracoid and inserted halfway down the inner side of the humerus, and a smaller long head rising from the glenoid border and inserted partly upon the humerus near the short-head insertion, and partly by a fine tendon upon the radiu?. The brachialis internus is of great size, and seems to have more or less usurped the function of the biceps. The tendons of the extensor digitorum communis branch out at the wrist at a wide angle, and when in action would strongly adduct the digits. The supinator longus is attached to the carpus (a common insertion among Marsupials). Only one ex- tensor carpi radialis is present. The pronator teres is fused with the flexor carpi radialis. This composite muscle and the flexor sublimis pass very obliquely across the fore- arm, and doubtless have a strong pronating action. Tho 123 PHYSIOLOGICAL SERIES. triangular space between tlie ulna and the outer side of the little finger is occupied by a large muscular sheet (flexor carpi ulnaris ?) which forms a powerful abductor minimi digiti. The interossei are remarkably developed. The following muscles are absent : teres minor, coraco-brachialis, supinator brevis. 0. 0. 281 E. Presented by the Directors of the Brighton Aquarium. Murie, Trans. Zool. Soc, vol. viii. 1874, p. 156. C. 148. Superficial muscles of the right fore-limb of a foetal African Elephant {Elephas africanus). The muscles are all of a distinctly massive type, and being for the most part fleshy close down to their insertions, form a stout supporting and stiffening investment to the limb-skeleton. A strong ligamentous band (partly elastic) covers the extensor lateralis, and elastic tissue is associated with the flexor carpi radialis. The following special features deserve notice : — The tendon of the latissimus dorsi is double, and embraces that of the teres major. The dorso-epitrochlearis rises to a great extent from the posterior angle of the scapula. The biceps is represented only by the long head. The pronator teres is rudimentary. The supinator longus is attached to the carpus. 0. C. 64 x a. C. 149. Left fore-limb of a foetal African Elephant {Elephas africanus), showing the deeper muscles, especially those of the fore-arm. 0. C. 64 x b. Miall & Greenwood, Jour. Anat. & Phys., vol. xii. 1878, p. 264. C. 150. Two transverse sections through the proximal part of a muscle (flexor carpi radialis ?) from the fore-limb of an Indian Elephant (^Elephas indicus), showing a remarkable development of elastic tissue in the perimysium. The elastic tissue forms a stout layer upon the outer surface of the muscle, occupying a quarter of the circumference and connected to a variable extent with a series of elastic sheets and strands that pass between the muscle-bundles. (Fig. 5.) Presented by Lord George Sanger, Esq^. FORE-LTMB. 129 C. 151. The remainder of the same muscle. Part of its deep surface has been dissected away to show the arrangement of the elastic tissue between the muscle bundles in sheets Fig. 5. of variable thickness ; the stoutest of these, in which the fibres are approximately parallel to the long axis of the fasciculi, lie in the interspace where several fasciculi meet ; they are connected by thinner sheets in which the fibres take a course diagonal to the fasciculi. Towards the distal end of the muscle the elastic sheets have a more ribbon-like character and are inserted upon the inner surface of the tendon. Upon the reverse aspect of the speciroen the superficial layer of elastic tissue is shown ; halfway down the muscle it abruptly assumes the struc- ture of an ordinary tendon. This great development of elastic tissue in the fjexor of the wrist is doubtless connected with the weight of the animal, and probably both assists in the elastic support of the normally over-extended foot and diminishes the risk of rupture of the muscle or tendon under the sudden strain thrown upon them during rapid locomotion. Presented hy Lord George Savger, Esq. C. 152. Right fore-foot of a Horse (Eguus cahallus), showing the intrinsic muscles and tendon attachments. Owing to the excessive reduction in the number of digits, the in- trinsic muscles are few. Two lumbricals are present (in K 130 PHYSIOLOGICAL SERIES. the specimen most of the inner one has boen removed), originating from the sides of the deep flexor tendon and inserted into the fetlock. The interossei of the splint- bones are rudimentary and lie between them and the metacarpal, while the short flexor of iii. dig. has been transformed into the great posterior suspensory ligament of the fetlock. 0. C. 284 m. C, 153. Right fore-limb of a Calf {Bos taurus), showing the superficial muscles. The reduction in number of the digits and the acute angles at which the several bones meet indi- cate that the limb is suitable for rapid movement. The muscles, with the exception of the extensor antebrachii, are of slender build, but occasionally {e.g. teres major, brachialis internus) gain considerable extra power by their insertion at a distance from the joint. As in the bird's wing (C. 135) the limb is rendered light and mobile by the concentration of the weight towards the proximal end, the distal tendons being of great length. Increased rigidity of the elbow-joint is gained by the loss of all movements of pronation and supination ; in consequence, pronators and supinators are absent. The following details are of special interest : — The biceps is represented by the long head only, the tendon of origin lies outside the capsule of the shoulder-joint, its insertion is upon the radius. The extensor digitorum com- munis is double ; the tendon of the inner head is attached to III. dig., that of the outer to lll. dig. and iv. dig. The extensor carpi ulnaris is fused at its insertion with the flexor carpi ulnaris. In front of the flexor carpi radialis there is a fibrous band, which probably represents the pronator teres. 0. C. 64 x e. Presented by Colonel Burgess. C. 154. Left fore-limb of a Calf {Bos taurus), showing the deep muscles. On the extensor surface a small slip is shown which, rising from the ulna, passes over the extensor pollicis and unites with the extensor communis. The flexor pro- fundus rises by three very distinct heads from the humerus, olecranon, and radius respectively. There are no lumbricals. 0. C. 64 Presented by Colonel Burgess, FORE-LIMB. 131 C. 155. Right fore-limb of a Seal {Phoca vitulina), showing the superficial muscles. The adaptation of the limb to a swimming life is shown in its musculature by the high development of the rotator muscles, especially those of pronation. During the backward stroke the palmar surface of the hand is turned outwards by the action of the usual pronator miiscles assisted by some of the flexors (flexor carpi ulnaris, palmaris longus) which run from the point of the elbow towards the radial margin of the hand. At the same time the digits are spread by an abductor minimi digiti arising from the elbow, and inserted in the subcuta- neous tissue on the outer side of the little finger. Supina- tion takes place during the recovery, whereby the narrow anterior border of the limb is turned to the front and off"ers the minimum of resistance to the water. In this action the usual supinators are assisted by the extensor pollicis brevis and extensor ossis metacarpi pollicis. The following muscles show exceptional features : — A fasciculus of the extensor antebrachii (marked * in the specimen) rising from the vertebral end of the scapula posterior to the spine and inserted partly into the elbow, partly into the abductor minimi digiti (it is sometimes called dorso-epitrochlearis, but this name seems better applicable to a tendinous strand running from the latissimus dorsi to the internal condyle). The latissimus dorsi is in two parts — one inserted into the teres major, the other into the outer bicipital ridge with the pectoralis major. The extensor digitorum communis is double. C. 156. Left fore-limb of a Seal (Phoca vitulina), showing the deep muscles. There is a small sabscapularis accessorius, which rises from the posterior border of the scapula near the glenoid and is inserted into the joint-capsule and upper part of the humerus. Miller, Challenger Reports, Zool. vol. xxvi. 1888, p. 142 ; Lucse, Abhandl. Senckenberg. Naturf. Gresellsch., Bd. ix. 1873-75, p. 474. C. 157. Right humerus and part of the fore-arm of a Dog (Cants J'amiliaris), showing the brachialis internus. The nmscle is k2 132 rHYSIOLOGICAL SERIES. of large size ; it has a usual but generalized mammalian origin from the posterior and outer surfaces of the proximal half of the humerus and winds spirally around that bone. It joins the tendon of the biceps at its distal end, and is inserted with it by a bifurcated tendon upon both ulna and radius. 0. C. 64 z g- a. Presented hy Prof. McFadyean. Ellenberger & Baum, Anatomic des Hundes (Berlin, 1891), p. 198. C. 158. Radius and ulna of a Dog ( Canis famiUaris) , with the rotator muscles. The pronator quadratus is very strongly developed, and occupies nearly the whole of the interosseous space. The upper part is possibly a precursor of the deep portion of the pronator teres. The biceps is attached to both ulna and radius. Presented hy Prof. McFadyean. Macalister, Jour. Anat. and Physiol., vol. ii. 1868, p. 8. C. 159. Left hand and part of the fore-arm of a Spider Monkey {Ateles sp.). The suppression of the thumb gives rise to a hook-like prehensile hand somewhat similar to that of the Sloth, but far more mobile. The tendon of the extensor metacarpi pollicis is of exceptional strength, and acts upon the hand, as a whole, through the mediation of the thumb- rudiment. The other long extensors of the thumb are absent. The thumb-attachment of the first interosseous muscle is retained. A blue rod is placed beneath the tendon of the extensor ossis metacarpi pollicis, and a green rod between the thumb-rudiment and the index. 0. C. 64m&(i. Leche, Bronn's Thier-reichs, Bd. vi. (Mammalia), 1897, p. 843. C. 160. Left arm of a Baboon { Papio \ Cynoceplialus] bahuin), showing the chief muscles *. In this ape, which in its locomotion is to a great extent quadrupedal, the muscles in general are powerful and, when compared with those of * In dealing with the Old World Apes great assistance has been derived from an unpublished work on Catarrhine Myology, kindly lent by the author, Dr. Arthur Keith. FORE-LIMB. 133 monkeys whose arms are mainly used for prehension, show a marked development of the extensor antebrachii group. The following features are of interest, particularly in their relation to the Anthropomorpha ; — The latissimus dorsi is united with the teres major before its insertion. The dorso- epitrocblearis is large. A coraco-brachialis brevis is present (a fairly constant muscle in Cyuomorpha, but usually absent in Anthropomorpha). The three parts of the deltoid are very distinct, leaving a considerable gap between the acromial and spinal portions. The epitrochleo-anconeus is well-developed. Palmaris longus fairly strong. There is no extensor polHcis brevis. 0. 0. 64 D. Champneys, Jour. Anat. & Physiol., vol. vi. 1871, p. 178. C. 161. Right fore-limb of a Crested Baboon {Cynopithecus niger), showing the dorso-epitrocblearis, coraco-brachialis (brevis and medius), and bracbialis internus muscles. O.C. 64m C. 162. Eight fore-limb o^Mucacus rnaurus showing the muscles. As a whole they do not display the powerful development of the Baboon (C. 160), but in their details the two limbs are closely similar. In addition to the features pointed out in connection with the Baboon, it may be noted that the deltoid is not separated into its three divisions and the pronator teres is inserted somewhat lower down the radius. Blue rods have been placed beneath the coraco-brachialis brevis, extensor profundus, and the extensor digitorura lateraHs. The latter- sends tendons to both iv. dig. and v. dig. (this is general in Orangs, Gibbons, and Cyuomorpha). 0. C. 64 MCI. Presented hy J. Ahraliams, Esq. Haughton, Proc. Irish Acad., vol. ix. 1867, p. 283. C. 163. Right arm and half the chest- wall of a Gibbon (Ilylobates leucisGus), showing the superficial muscles. In this essen- tially arboreal anthropoid, the flexors of the elbow greatly exceed the extensors in size and strength, but the disproportion is not carried to the fore-arm as in the Sloth (C. 146). The following details are noteworthy in comparison with other Anthropoids. The deltoid extends more than halfway down the humerus. The supinator 134 PHYSIOLOGICAL SERIES. longus is attached very high up on the radius. The pronator and supinator muscles are weak, as well as all the muscles belonging to digit v. There is no extensor pollicis brevis. 0. C. (34 M i. For the Anthropoids : Hepburn, Jour. Anat. & Physiol., vol. xxvi. 1891-92, p. 149. C. 164. Left arm of a Gibbon {Hylohates leuciscus), showing the deep muscles. The pectoralis minor is attached to clavicle and coracoid process. The latissimus dorsi (as in the other Anthropoids with exception of the Gorilla) is united to the teres major before its insertion. The dorso-epitrochlearis is short and broad ; its fibres run diagonally to the inter- muscular septum, and are attached to it between the proximal two-thirds. The short head of the biceps arises from the coracoid, and from nearly the whole length of the humerus ; most of its fibres join the long head, but those that rise nearest the elbow run directly to the surface of the supinator longus. There is a flexor longus pollicis. 0. C. 64Mm. Keith, Nat. Sci., vol. ix. 1896, p. 373. C. 165. Right arm of an Orang-Outang {Simia satyrus) and lower part of the left arm, showing respectively the super- ficial and deep muscles. The pectoralis major has a slight origin from the clavicle. The pectoralis minor is attached to the coracoid and scapular end of the clavicle. The dorso- epitrochlearis is of medium development. There is no eoraco-brachialis brevis. The two heads of the biceps are separate through their whole extent (a fairly common variation in the Orang) ; both are inserted on the radius ; there is no fascial insertion. Pronator teres and supinator longus are both inserted higher up the radius than in Man. There is no tendon from the flexor profundus to the thumb. Extensor pollicis brevis is present as a subdivision of the extensor ossis metacarpi pollicis. The pronator quadratus is very weak. Extensor lateralis (ext. min, dig.) supplies iv. dig. & V. dig. 0. C. 64 m cL Presented by C. Dent, Estj. C. 166. Distal part of the right arm of an Orang-Outang {Simia satyrus), in which the deep flexors and lumbricals are more FORE-LIMB. 135 clearly shown than in the last specimen. Between the tendons to ill. & iv. there is a fine tendon, inserted partly into tendons lii. & iv. and partly into the lumbrical. 0. C. 6inda. Presented hy Victor Horsley, Esq. Keith, Nat. Sci., ix. 1896, p. 317. C. 167. Eight arm and half the chest- wall of a Gorilla {Anthropo- pithecus gorilla), showing the superficial muscles. The pectoralis major has a large clavicular origin ; its two parts are separated from each other and from the deltoid by considerable gaps. The epitrochleo-anconeus is fibrous. The flexor carpi radialis has an extensive origin from tlie oblique line of the radius. The palmaris longus is absent. An extensor poUicis brevis is present. 0. C. 64 N a. C. 168. Deep muscles and arteries of the left arm of a Gorilla [Anthropopithecus gorilla) . The pectoralis minor is attached to the coracoid process in common with the short head of the biceps. The teres major and latissimus dorsi are separately attached to the humerus. Coraco-brachialis brevis is absent. The dorso-epitrochlearis is almost rudimentary ; it joins the extensor antebrachii. The extensores carpi radialis longus and brevis are separate from their origin. 0. C. 61 N h. Keith, Nat. Sci., ix. 1896, p. 28. C. 169. Superficial muscles of the right fore-limb of a Chimpanzee (Anthropoj)ithecus troglodytes). The three parts of the deltoid are readily separable from one another. The dorso- epitrochlearis is tendinous for its distal third and extends down to the inner condyle. The coraco-brachialis is remark- able ; it is represented by medius and longus : the longus arises from the inner surface of the short head of the biceps, and has a double insertion, (1) by several fibres into the anterior border of the dorso-epitrochlearis, and (2) into the inter-muscular septum between brachiahs internus and extensor antebrachii near the internal condyle. The supinator longus has a two-fold origin from the outer side of the humerus ; the two heads unite about the middle of the fore-arm ; their common tendon is attached close above the styloid process of the radius. The extensor carpi uluaris gives off u small slip to the annular ligament. 136 PHYSIOLOGICAL SERIES. The two portions of tlie adductor pollicis (transversns and obliquus) are entirely distinct. Presented hy John Marshall, Esq. C. 170. Left fore-limb of the same Chimpanzee, showing the nerves and deep muscles. The pectoralis minor is attached to the head of the humerus. The coraco-brachiahs is represented by the medius, perforated by the musculo- cutaneous nerve. The fle.tor carpi radialis has a supple- men taiy tendon of attachment to the trapezium (indicated by a black bristle). The radial segment of the flexor pro- fundus supplies the index and gives off a small muscular slip and tendon (flexor longus pollicis) to the thumb. The foui-th lunibrical has a double origin from tendons iv. & x. of the flexor profundus. Presented by John Marshall, Esq. C. 171. Left elbow of a Chimpanzee {Anthropopiiliecics troglo- dytes), showing the supinator brevis. The muscle is broken up into several laminae, distinguishable mainly from the different course of their muscle-fibres, and is overlaid by a remarkable sheet of muscle (indicated by a blue rod) that rises from the outer side of the humerus close above the condyle beneath the extensor carpi radialis, and is inserted into the radius with the distal part of the underlying supinator brevis. C. 172. Deep muscles of the left hand and distal part of the arm of a Chimpanzee {Anthropopithecus troglodytes) . The rudi- mentary tendon that represents the flexor longus pollicis rises from the sheath of the flexor profundus tendon ii. Besides the usual three adductor palmar interossei, there are also upon this surface of the hand four abductor interossei attached to the sides of the first phalanges of digits ii., iii., IV. (blue rods are placed beneath their tendons). These muscles are probably not true palmar interossei, but slips from the dorsal interossei that have migrated to the pahnar surface. Each of the extensors of the thumb is inserted one bone above its usual human attachment. Hepburn, Trans. R. Soc. Edinburgh, vol. xxxviii. 1897, p. 557 ; Keith, Nat. Sci., vol. ix. 1896, p. 251. HIND-LIMB, 137 Hind-liml). C. 173. The muscles of the right pelvic fin of a Dog-fish (Sct/llium catulus) . The deep and superficial muscle-layers on hoth surfaces of the fin are inserted into the horny fin- rays. On the ventral surface they are only recognizable as distinct layers by the different direction of their fibres. Those of the superficial sheet rise from the pelvis and median tendinous septum and run directly to the rays ; while those of the deeper layer are interrupted in their course by the basal pterygia. On the dorsal surface the layers are more distinct; the superficial rises from the general aponeurotic sheath of the trunk, and runs in well- defined bundles to the fin-rays (a deeper slip of this muscle (A) is attached to the base of the clasper) . The deep layer rises from the basal pterygia. Davidofif, Morph. Jahrb., Bd. v. 1879, p. 454. C. 174. Eight pelvic fin of a Sea-Cat {Chimcera monslrosa), showing the muscles. Upon the ventral surface the layers are simple in character and not very clearly defined, but upon the dorsum the superficial sheet shows marked indi- cations of subdivision into three independent muscles (superf. A, B, C). The anterior part of superf. A, from its position, would act as a protractor of the fin. Davidofi^, Morph. Jahrb., Bd. v. 1879, p. 473. C. 175. Eight pelvic fin of a Cod {Gadus morrhita), showing the muscles. The superficial layer (Su) on both surfaces of the fin is divided into several well marked muscles, which, according to their position, act as dilators, approximators, levators, or depresso.-s. The deep layer (Pr) on both surfaces is simple. All the muscles are attached to the base of the fin-rays. C. 176. The hind limbs of a Hell-bender {Cryptohranchus allegJian- iensis), showing the superficial muscles in the upper speci- men, the deep muscles in the lower. The arrangement of the muscles in simple superficial and deep layers is more strongly marked than in the fore-limb ; it can best be seen in the muscles on the inner surface of the thigh. The following are the names of the individual muscles (indicated by numbers 138 PHYSIOLOGICAL SERIES. and capital letters).—!. Pubo-iscliio tibialis : a large sheet that corresponds to the pubo-ischio-tibialis of the Lizard. 2. Candali pnbo-ischio-tibialis ; where this muscle unites with the pubo-ischio-tibialis there is a slight tendinous inter- section ; it has been suggested that this may have some relation to the intersection seen in the semitendinosus of Man. 3. Ischio-flexorius. 4. Ischio-caudalis. 5. Pubo- ischio-femoralis externus. G. Pubo-ischio- femora lis internus. 7. Caudali femoris. 8. Ilio-extensorins, part i. ; this muscle expands into a tendinous sheet over the knee, and is continued as a fine tendon to the distal end of the tibia between the femoro-tibialis (0) and femoro- digiti i-v. (D). 8.* llio-extensorius, part ii. 9. ]lio- femoro-fibularis (iliac head). 9.* Ilio-femoro-fibularis (femoral head) : these two muscles roughly correspond to the biceps. 10. llio-femorahs. A. Femoro-fibulse digiti i-v. : a muscle that possibly represents gastro- cnemius, soleus, plantaris, and flexor brevis digitorum. B. Femoro-fibulse metatarsi i., ii., m. c. Femoro- tibialis. D. Femoro-digiti i-v. E. Fibulae metatarsum ii. F, Femoro-fibularis. G. Tarsu-digiti I- v. De Man, Niederl. Arch. f. Zool, Bd. ii, 1874-75, p. 61. C. 177. Superficial muscles of the right hind-limb of a Lizard (Varanus sal valor). The simple sheets of muscle seen in the fish, and to a less extent in the Urodele, are here broken up into numerous individual muscles, but traces of their original continuity can be seen in the connexions that occur, both between laterally contiguous muscles and those of different segments of the limb. An excellent example of this continuity is afforded by the gastrocnemius, which passes over the heel as a flat tendon to form the point of origin for the short flexors of the foot. The muscles, owing to their generalized character, cannot be directly compared with those of mammals, but they show many points of resemblance to the Bird, the most noteworthy being the presence of an accessory rectus femoris internus (ambiens), a purely reptilian and avian muscle usually continued over the knee to join one of the flexors of the shank, but here inserted upon the crest of the tibia with the femoro-tibialis. HIND-LIMB. 139 The following muscles should he noticed : — Puho-ischio- tibialis, a large powerful muscle prohably answering to the mammalian gracilis ; it is absent in Chelonians, Crocodiles, and Birds. The pubi-tibialis, a double muscle, though single in many Lizards ; it is absent in the Crocodile. The two peronei are separate ; in many Lizards they form a single mass. The inner head of the gastrocnemius is tibial in origiii and double. 0. C. 64 Y v. C. 178. Left hind-limb of a Lizard (Varanus salvator), showing the deep muscles. The connection between the flexor tibialis externus and internus and the second part of the inner head of the gastrocnemius should be noted ; also a curious long slender tendon rising from the lower margin of the caudi-femoralis and inserted upon the tibia in conjunction with the pubi-tibialis. 0. C. 64 Y w. Gadow, Morph. Jahrb., Bd. vii. 1882, p. 329. C. 179. Left hind-limb of a Crocodile {Crocodilus acutus), showing the nerves and superficial muscles. Several that in the Monitor are single are here replaced by two, for instance— ilio-fibularis, caudi-femoralis, ambiens. Several also are entirely absent, notably the large pubi-ischio- tibialis. The first part of the ambiens is strikingly bird-like ; its tendon passes diagonally outwards over the knee and is inserted into the peroneus posterior. More or less intimate connections occur between the superficial muscles in the region of the ankle; thus, the tibialis anticus joins the extensor longus digitorum, and the peronei unite with one another and with the gastrocnemius. The great size of the caudi-femoralis indicates its importance. It seems to act not only as a retractor of the whole limb, but also to produce the lateral movements of the tail. 0. C. 63 G. C. 180. Nervesand deep muscles of the right hind-limb of a Croco- dile ( Crocodilus acutus) . The flexor tibialis internus is more complex than in the Monitor : two of its divisions unite in a common tendon with the flexor tibiahs externus. The tendon is forked and inserted by one end upon the neck of the tibia, and by the other, which runs down the leg parallel 140 PHYSIOLOGICAL SERIES. to the inner head of the gastrocnemius, to the plantar fascia. This hitter tendinous extension seems to represent the similarly disposed slip of the gastrocnemius of the Monitor. The long tendon of the caudi-femoralis is inserted into the outer head of the gastrocnemius. 0. C. (53 h. Gadow, Morph. Jahrb., Bd. vii. 1882, p. 375. C. 181. Portions of tendons from an Ostrich (Struthio camelus), showing two passing through a sheath formed by a third, which, intervening between them and the centre of motion, acts as a patella to them. 0. C. 274. Ilunterian. C. 182. The parts constituting the tarsal joint of an Ostrich. The flexor tendons of the toes pass through a sheath in the tendo Achillis, which is considerably thickened at that part ; and while it securely retains them in their proper situation, removes them further from the centre of motion at that joint, and augments the lever of the moving power. 0. C. 275. Huntetian. C. 183. The tendons and ligaments of the joints of the toes of the Ostrich {Struthio camelus). The sheath of the flexor tendons is of extraordinary thickness behind the metatarso- phalangeal joint. 0. C. 275 B. C. 184. A vertical section of the tarso-metatarsal bone and phalanges of the greater toe of an Ostrich (Struthio camelus) , and of their flexor tendons. Each bone has its proper tendon inserted into it, which forms a sheath for the tendon of the succeeding phalanx : and on the ])lantar aspect of each joint is situated a ligamentous substance (analogous to those in the human linger), forming part of that joint, and playing on an articular surface in the lower extremity of the superior bone. These act like patellas, removing the flexor tendons farther from the centres of motion of their respective joints, and forming so many elastic cushions to protect the joints and obviate the effects, by diffusing the forces, of pressure and percussion. 0. C. 276. Hunterian. C. 185. Superficial muscles of the right hind limb of a Rook {Trypanocorax frugilegus). Union between the muscles of HIND-LIMB. 141 tbo different segments of the limb is not so noticeable as in Eeptiles. The only connection of the kind which may perhaps be compared with that between the flexor tibialis externus and gastrocnemius of Reptiles, occurs between the tendinous intersection of the caud-ilio-flexorius and the inner head of the gastrocnemius. The common gastrocnemius tendon (formed by the union of a tibial and two femoral heads) is likewise continued over the heel to the middle of the tarso-metatarsns. Certain muscles of the i\i{g\i — ambiens (absent in the Rook), ilio-tibialis, the two portions of the cand-ilio-femoralis, and the two portions of caud-ilio-flexorius — are noteworthy for the approximately constant variations they exhibit in difFerent groups of birds. In a similar Avay the particular mode of arrangement and connection of the deep plantar tendons has been used for taxonomic purposes. The heel is capped by a large sesamoid cartilage, which, as was seen in the previous specimen of the Ostrich, removes the tendons that pass over it to a suitable distance from the centre of motion. 0. 0. 64 Y r. Presented by St. George Mivart, Esq. 186. Right hind-limb of a Rook (Trypanocorax fruyilegm), showing the deep muscles. The caud-ilio-flexorius is divided near its insertion into two parts by a tendinous intersection. The muscle-fibres on the distal side of the intersection are arranged at an angle to the long axis of the proximal and larger part of the muscle, and are attached to the femur close above the condyle. The ilio- flbularis (biceps), before its insertion upon the fibula, passes through a pulley-like tendinous loop that stretches from the external femoral condyle to the origin of the flexor perforatus iv. By means of this mechanism the power of flexing the shank upon the thigh is greatly enhanced. The long flexors of the foot are very much subdivided. The short extensors are reduced to a curious little extensor hallucis brevis, which rises from the anterior surface of the tarso-metatarsus and passes round the outer surface of the first metatarsus to the dorsal surface of the backwardly directed hallux. 0. 0. 64 Y s. Presented by St. George Mivart, Esq. Shufeldt, Myology of the Raven (London, 1890), p. 155. 142 rHYSIOLOGICAL SERIES. The following seven specimens are designed to show the arrangement of certain thigh-muscles — ambiens, caud-ilio- femoralis 2 parts (femoro-caudal + accessory femoro-caudal, Garrod), caud-ilio-flexorius 2 parts (semitendinosus + accessory pemitendinosiis,6ran'0f?), and ilio-tibialis (tensor fasciae, G^arrot^j, and the branches of the great sciatic nerve. Garrod, Proc. Zool. Soc. 1873, p. 626. C. 187. Thigh with the pelvis and upper part of the shank of a Kiwi {Apteryx mantelli) (subclass Struthioniformes). In this bird all the muscles in question are present. The iliac part of the caud-ilio-femoralis is, however, peculiar, being perforated by the sciatic nerve — a condition only found in Struthiones and Crypturi. A blue rod is placed beneath the portion of the pars ilio-femoralis posterior to the perforation for the sciatic nerve < a pale blue rod beneath the pars caudi-femoris ; and black bristles beneath the tendon of insertion of the arabiens. 0. C. 64 Y h. C. 188. A similar specimen of the thigh-inuscles of Pau.vi mitu (suborder Gallinee, order Gallograllae, subclass Galliformes). In this bird all the muscles are present. The pars caudi- femoris of the caud-ilio-femoralis is, how^ever, very slender. O.C. 64 T a. C. 189. Muscles of the thigh of a Great Bustard [Otis tardci) (suborder Fulicarise, order Gallograllae). The pars caudi- femoris of the caud-ilio-femoralis is absent. 0. C. 64 y /. C. 190. Muscles of the thigh of a Tree- Duck (Dendrocygna autumnalis) (subclass Anseriformes). The pars accessorius of the caud-ilio-flexorius is absent. The pars ilio-femoris of the caud-ilio-femoralis is very strongly developed. O.C. 64yc. C. 191. Muscles of the thigh of a Buzzard (Buleo tachardus) (subclass Falconiformes) . All the muscles in question but the ambiens and pars caudi-femoris of the caud-ilio- femoralis are absent. O.C. 64 Y d. HIND-LIMB. 143 C. 192. Muscles of the thigh of a, King Vulture {Catharten papa) (order Pseudogryphii, subclass Coraciiformes). Both parts of the caud-ilio-femoralis are absent. 0. C. 64y