The works of Francis Maitland Balfour, Volume 3 (of 4)

by Francis M. Balfour

• Labia majora, development of, [727]
• Labial cartilages, [597]
• Labium tympanicum, [525];
  • vestibulare, [525];
• Lacertilia, general development of, [202];
  • nares of, [537];
  • pectoral girdle of, [603];
  • pelvic girdle of, [607];
  • arterial system of, [649];
• Lacrymal bone, [593]
• Lacrymal duct, [506]
• Lacrymal glands, [506]
• Læmargus, vertebral column of, [548]
• Lagena, [524]
• Lamina spiralis, [524]
• Lamina terminalis, [438]
• Larva of Amphioxus, [2];
  • of Ascidia, [15]-21;
  • Teleostei, [81];
  • Petromyzon, [89], [95];
  • Lepidosteus, [117], [318];
  • Amphibia, [134], [142];
  • types of, in the Invertebrata, [363];
• Larvæ, nature, origin, and affinities of, [360]-386;
  • secondary variations of less likely to be retained, [362];
  • ancestral history more fully recorded in, [362];
  • secondary variations in development of, [363];
  • ontogenetic record of secondary variations in, [361];
  • of freshwater and land animals, [362];
  • types of, [362];
  • phosphorescence of, [364];
  • of Coelenterata, [367];
  • table of, [365];
  • of Invertebrata, [367] et seq.
• Larynx, [766]
• Lateral line sense organs, [538];
  • comparison of, with invertebrate, [538];
  • development of, in Teleostei, [538];
  • development of, in Elasmobranchii, [539];
• Lateral ventricle, [438];
  • anterior cornu of, [440];
  • descending cornu of, [440];
  • choroid plexus of, [443];
• Layers, formation of, in Elasmobranchii, [41], [56];
  • Teleostei, [71];
  • Petromyzon, [85];
  • Acipenser, [103];
  • Lepidosteus, [111];
  • Amphibia, [121];
  • Chick, [150], [152];
  • Lacerta, [202];
  • Rabbit, [215]-227;
  • comparison of Mammalia with lower forms, [226], [289];
  • comparison of formation of in Vertebrata, [275];
  • origin and homologies of, in the Metazoa, [331];
• Leech, _see_ ‘Hirudo’
• Lemuridæ, placenta, [256]
• Lens, of Elasmobranchii, [57], [58];
  • Petromyzon, [94], [99];
  • Acipenser, [106];
  • Lepidosteus, [115];
  • Amphibia, [127];
  • Chick, [177];
  • of Vertebrate eyes, [485];
  • general account of, [493];
  • capsule of, [493];
  • comparative development of, [499];
  • of Amphibia, Teleostei, Lepidosteus, [499];
• Lepidosteus, development of, [111];
  • larva of, [117];
  • relations of, [119];
  • spinal nerves of, [455];
  • ribs of, [561];
  • generative ducts of, [704], [735];
  • swimming-bladder of, [763];
• Ligamentum pectinatum, [490]
• Ligamentum suspensorium, [557], [558]
• Ligamentum vesicæ medium, [239]
• Limbs, of Elasmobranchii, [59];
  • Teleostei, [80];
  • first appearance of in Chick, [184];
  • Rabbit, [232];
  • muscles of, [673];
  • of Fishes, [609];
  • relation of, to unpaired fins of Fishes, [611], [612];
  • of Amphibia, [618];
• Liver of Teleostei, [78];
  • Petromyzon, [95], [96];
  • Acipenser, [110];
  • Amphibia, [130];
  • general account of, [769];
• Lizard, development of, [202];
  • general growth of embryo of, [208];
  • Müllerian duct of, [721];
• Lizzia, eye of, [471]
• Lobi inferiores, [431]
• Lungs of Amphibia, [137];
  • development of, [763];
  • homology of, [766];
• Lymphatic system, [664]

• Malleus, [529], [591];
  • views on, [591];
• Malpighian bodies, development of accessory in Elasmobranchs, [695]
• Mammalia, development of, [214];
  • comparison of gastrula of, [291];
  • cerebellum of, [427];
  • infundibulum of, [431];
  • pineal gland of, [434];
  • pituitary body of, [436];
  • cerebrum of, [439];
  • spinal nerves of, [449];
  • sympathetic of, [466];
  • vertebral column of, [558];
  • branchial arches of, [573], [574];
  • mandibular and hyoid arches of, [589];
  • pectoral girdle of, [604];
  • pelvic girdle of, [608];
  • heart of, [636];
  • arterial system of, [647];
  • venous system of, [661];
  • muscle-plates of, [671];
  • mesonephros of, [714];
  • testicular network of, [724];
  • urinogenital sinus of, [727];
  • spermatozoa of, [747];
  • lungs of, [765];
  • intestines of, [768];
  • liver of, [769];
  • postanal gut of, [774];
  • stomodæum of, [775];
• Mammary gland, development of, [398]
• Man, placenta of, [244];
  • general account of development of, [265];
  • characters of embryo of, [270];
• Mandibular arch of Elasmobranchii, [62], [576];
  • Petromyzon, [91];
  • Acipenser, [106], [116];
  • Chick, [179];
  • general account of, [572], [575];
  • modification of to form jaws, [573], [575];
  • of Teleostei, [580];
  • of Amphibia, [582];
  • Sauropsida, [588];
  • Mammalia, [589];
• Mandibular bar, evolution of, [311], [321]
• Manis, placenta of, [256]
• Marsupial bones, [608]
• Marsupialia, foetal membranes of, [240];
  • cerebellum of, [426];
  • corpus callosum of, [443];
  • uterus of, [726];
• Maxilla, [594]
• Meatus auditorius externus, of Chick, [181];
  • development of, [527];
• Meckelian cartilage, of Elasmobranchii, [576];
  • of Teleostei, [581];
  • of Amphibia, [584], [585];
  • of Sauropsida, [588];
  • of Mammalia, [590];
• Mediastinum anterior and posterior, [630]
• Medulla oblongata, of Chick, [176];
  • general development of, [425];
• Medullary plate of Amphioxus, [4], [5];
  • of Ascidia, [11];
  • Elasmobranchii, [44], [47], [55];
  • Teleostei, [72];
  • Petromyzon, [88];
  • Acipenser, [104];
  • Lepidosteus, [111];
  • Amphibia, [126], [127], [131];
  • Chick, [159];
  • Lacerta, [204];
  • Rabbit, [223], [227], [228];
  • primitive bilobed character of, [303], [317];
• Medusæ, auditory organs of, [513]
• Membrana capsulo-pupillaris, [494], [504], [507]
• Membrana elastica externa, [546]
• Membrana limitans of retina, [491]
• Membrana tectoria, [522], [525]
• Membrane bones, of Amphibia, [582];
  • of Sauropsida, [588];
  • of Mammalia, [590];
  • of mandibular arch, [593];
  • of pectoral girdle, [599], [602];
  • origin of, [592];
  • homologies of, [593];
• Membranous labyrinth, development of in Man, [519]
• Menobranchus, branchial arches of, [142]
• Mesenteron of Elasmobranchii, [43];
  • Teleostei, [75];
  • Petromyzon, [85];
  • Acipenser, [104];
  • Amphibia, [123], [124], [129];
  • Chick, [167];
  • general account of, [754]
• Mesentery, [626], [756]
• Mesoblast, of Amphioxus, [6];
  • Ascidia, [17], [20];
  • Pyrosoma, [24];
  • Salpa, [30];
  • Elasmobranchii, [44], [47];
  • Teleostei, [75];
  • Petromyzon, [86];
  • Acipenser, [105];
  • Lepidosteus, [113];
  • Amphibia, [125], [128], [129];
  • of Chick, [154], [167];
  • double origin of in Chick, [154], [158], [159];
  • origin of from lips of blastopore in Chick, [158];
  • of area vasculosa of Chick, [160];
  • Lacerta, [203];
  • origin of in Rabbit, [218], [223];
  • of area vasculosa in Rabbit, [227];
  • comparative account of formation of, [292];
  • discussion of development of in Vertebrata, [297];
  • meaning of development of in Amniota, [298];
  • phylogenetic origin of, [346];
  • summary of ontogeny of, [349]-352;
  • views on ontogeny of, [352]-360;
• Mesoblastic somites, of Amphioxus, [6];
  • Elasmobranchii, [48], [55];
  • Petromyzon, [88];
  • Acipenser, [105];
  • Lepidosteus, [114];
  • Amphibia, [129], [131];
  • Chick, [161], [180];
  • Rabbit, [228];
  • development of in Chordata, [325];
  • meaning of development of, [331];
  • of head, [676]
• Mesogastrium, [758]
• Mesonephros, of Teleostei, [78], [702];
  • Petromyzon, [95], [98], [700];
  • Acipenser, [110], [705];
  • Amphibia, [134], [708];
  • Chick, [184], [714];
  • general account of, [690];
  • development of in Elasmobranchs 691;
  • of Cyclostomata, [700];
  • Ganoidei, [705];
  • sexual and non-sexual part of in Amphibia, [710];
  • of Amniota, [713], [724];
  • summary and general conclusions as to, [729];
  • relation of to pronephros, [731];
• Mesopterygium, [616]
• Metagenesis of Ascidians, [34]
• Metamorphosis of Amphibia, [137], [140]
• Metanephros, [690];
  • development of in Elasmobranchii, [697];
  • of Amphibia, [712];
  • of Amniota, [713];
  • of Chick, [722];
  • of Lacertilia, [723];
  • phylogeny of, [736];
• Metapterygium, [616]
• Metapterygoid, of Elasmobranchii, [576];
  • of Teleostei, [581];
• Metazoa, evolution of, [339], [342];
  • ancestral form of, [333], [345];
• Mid-brain, of Elasmobranchii, [55], [58], [59];
  • Petromyzon, [92];
  • general account of development of, [427];
• Moina, generative organs of, [745]
• Molgula, development of, [22]
• Mollusca, nervous system of, [414];
  • eyes of, [472];
  • auditory organs of, [515];
  • excretory organs of, [681];
• Monotremata, foetal membranes of, [240];
  • cerebellum of, [426];
  • corpus callosum of, [443];
  • cerebrum of, [443];
  • urinogenital sinus of, [726];
• Mormyrus, generative ducts of, [704]
• Mouth, of Amphioxus, [7];
  • of Ascidia, [18];
  • Pyrosoma, [27];
  • Salpa, [31];
  • Elasmobranchii, [57], [60], [61], [62];
  • Petromyzon, [92], [94], [95], [99];
  • Acipenser, [107];
  • Lepidosteus, [118];
  • Amphibia, [129], [132], [134];
  • Rabbit, [231];
  • origin of, [317];
• Mouth, suctorial, of Petromyzon, [99];
  • Acipenser, [107];
  • Lepidosteus, [116], [317];
  • Amphibia, [133], [141], [317];
• Müllerian duct, [690];
  • of Elasmobranchs, [693];
  • of Ganoids, [704];
  • of Amphibia, [710];
  • of Aves, [717], [720];
  • opening of into cloaca, [727];
  • origin of, [733];
  • summary of development of, [733];
  • relation of to pronephros, [733];
• Muscle-plates, of Amphioxus, [6];
  • Elasmobranchii, [49], [668];
  • Teleostei, [670];
  • Petromyzon, [94];
  • Chick, [183], [670];
  • general development of, [669];
  • of Amphibia, [670];
  • Aves, [670];
  • of Mammalia, [671];
  • origin of muscles from, [672];
• Muscles, of Ascidia, [11], [17];
  • development of from muscle-plates, [672];
  • of limbs, [673];
  • of head, [676];
  • of branchial arches, [678];
  • of eye, [678];
• Muscular fibres, epithelial origin of, [667]
• Muscular system, development of, [667];
  • of Chordata, [668];
• Mustelus, placenta of, [66]
• Myoepithelial cells, [667]
• Mysis, auditory organ of, [517]
• Myxine, ovum of, [100];
  • olfactory organ of, [533];
  • portal sinus of, [652];
  • excretory system of, [701];

• Nails, development of, [397]
• Nares, of Acipenser, [108];
  • of Ichthyopsida, [534];
  • development of in Chick, [535];
  • development of in Lacertilia, [537];
  • development of in Amphibia, [537];
• Nasal bones, [592]
• Nasal pits, Acipenser, [108];
  • Chick, [176];
  • general development of, [531];
• Nematoda, excretory organs of, [689];
  • generative organs of, [745];
  • generative ducts of, [752];
• Nemertines, nervous system of, [311];
  • excretory organs of, [681];
• Nerve cord, origin of ventral, [378]
• Nerves, spinal, [449];
  • cranial, [455]-466;
• Nervous system, central,
  • general account of development of in Vertebrata, [415];
  • conclusions as to, [445];
  • sympathetic, [466];
• Nervous system, of Amphioxus, [4];
  • Ascidia, [15], [16];
  • Molgula, [22];
  • Pyrosoma, [24], [25];
  • Salpa, [30], [31];
  • Elasmobranchii, [44];
  • Teleostei, [77];
  • Petromyzon, [89], [93];
  • Acipenser, [105];
  • Amphibia, [126];
  • comparative account of formation of central, [301];
  • of Sagitta, [349];
  • origin of in Coelenterata, [349];
  • of præoral lobe, [377], [380];
  • evolution of, [400]-405;
  • development of in Invertebrates, [406];
  • of Arthropoda, [408];
  • of Gephyrea, [412];
  • Mollusca, [414];
• Neural canal, of Ascidia, [10];
  • Teleostei, [72];
  • Petromyzon, [88];
  • Acipenser, [105];
  • Lepidosteus, [114];
  • Amphibia, [126], [131];
  • Chick, [166], [171];
  • Lacerta, [208];
  • closure of in Frog and Amphioxus, [279];
  • closure of in Elasmobranchii, [284];
  • phylogenetic origin of, [316];
• Neural crest, [449], [456], [457]
• Neurenteric canal, of Amphioxus, [4], [5];
  • Ascidia, [10];
  • Elasmobranchii, [54];
  • Petromyzon, [88];
  • Acipenser, [105];
  • Lepidosteus, [113];
  • Aves, [162];
  • Lacerta, [203], [206];
  • general account of, [323];
  • meaning of, [323];
• Newt, ovum of, [120];
  • development of, [125];
  • general growth of, [141];
• Notidanus, vertebral column of, [548];
  • branchial arches of, [572];
• Notochord of Amphioxus, [6];
  • Ascidia, [11], [17];
  • Elasmobranchii, [51];
  • Teleostei, [74];
  • Petromyzon 86, [94];
  • Acipenser, [104];
  • Lepidosteus, [113];
  • Amphibia, [128], [129];
  • Chick, [157];
  • canal of, in Chick, [163];
  • Lacerta, [204], [205];
  • Guinea-pig, [226];
  • comparative account of formation of, [292], [325];
  • sheath of, [545];
  • later histological changes in, [546];
  • cartilaginous sheath of, [547];
  • in head, [566];
  • absence of in region of trabeculæ, [567];
• Notodelphys, brood-pouch of, [121];
  • branchiæ of, [140];
• Nototrema, brood-pouch of, [121]
• Nucleus pulposus, [559]

• Oceania, eye of, [471]
• Occipital bone, [595]
• OEsophagus, solid, of Elasmobranchii, [61], [759];
  • of Teleostei, [78];
• Olfactory capsules, [571]
• Olfactory lobes, development of, [444]
• Olfactory nerves, Ammocoetes, [99];
  • general development of, [464];
• Olfactory organ, of aquatic forms, [531];
  • Insects and Crustacea, [531];
  • of Tunicata, [532];
  • of Amphioxus, [532];
  • of Vertebrata, [533];
  • Petromyzon, [533];
  • of Myxine, [533];
• Olfactory sacks, of Elasmobranchii, [60];
  • Teleostei, [73];
  • Petromyzon, [92], [97];
  • Acipenser, [106], [108];
  • Lepidosteus, [116];
  • Chick, [176];
• Oligochæta, excretory organs of, [683]
• Olivary bodies, [426]
• Omentum, lesser and greater, [757]
• Onchidium, eye of, [478]
• Opercular bones, [593]
• Operculum, of Teleostei, [77];
  • Acipenser, [107];
  • Lepidosteus, [117], [118];
  • Amphibia, [135];
• Ophidia, development of, [210];
  • arterial system of, [649];
  • venous system of, [656];
• Optic chiasma, [430], [493]
• Optic cup, retinal part of, [488];
  • ciliary portion of, [489];
• Optic lobes, [428]
• Optic nerve, development of, [492];
  • comparative development of, [500];
• Optic thalami, development of, [431]
• Optic vesicle, of Elasmobranchii, [57]-59;
  • Teleostei, [74], [499];
  • Petromyzon, [89], [92];
  • Acipenser, [106];
  • Lepidosteus, [115];
  • Chick, [170];
  • Rabbit, [229];
  • general development of, [429];
  • formation of secondary, [487];
  • obliteration of cavity of, [488];
  • comparative development of, [499];
  • of Lepidosteus and Teleostei, [499].
  • _See also_ ‘Eye’
• Ora serrata, [488]
• Orbitosphenoid region of skull, [570]
• Organs, classification of, [391];
  • derivation of from germinal layers, [392];
• Orycteropus, placenta of, [249]
• Otic process of Axolotl, [583];
  • of Frog, [585] et seq.
• Otoliths, [512]
• Oviposition, of Amphioxus, [1];
  • Elasmobranchii, [40];
  • Teleostei, [68];
  • Petromyzon, [84];
  • Amphibia, [121];
  • Reptilia, [202];
• Ovum, of Amphioxus, [1];
  • Pyrosoma, [23];
  • Elasmobranchii, [40];
  • Teleostei, [68];
  • Petromyzon, [83];
  • Myxine, [100];
  • Acipenser, [102];
  • Lepidosteus, [111];
  • Amphibia, [120];
  • Chick, [146];
  • Reptilia, [202];
  • Mammalia, [214];
  • of Porifera, [741];
  • migration of in Coelenterata, [742];
  • Vertebrata, [746];

• Palatine bone, of Teleostei, [580];
  • origin of, [594];
• Pancreas, Acipenser, [110];
  • general development of, [770];
• Pancreatic cæca, of Teleostei, etc. 768
• Papillæ, oral, of Acipenser, [108];
  • Lepidosteus, [116];
• Parachordals, [565], [566]
• Parasphenoid bone, [594]
• Parepididymis, [725]
• Parietal bones, [592]
• Paroophoron, [725]
• Parovarium, [725]
• Pectoral girdle, [599];
  • of Elasmobranchs, [600];
  • of Teleostei, [600];
  • of Amphibia and Amniota, [601];
  • comparison of with pelvic, [608];
• Pecten, eye of, [479]
• Pecten, of Ammocoetes, [498];
  • of Chick, [501];
  • Lizard, [501];
  • Elasmobranchs, [501];
• Pedicle, of Axolotl, [484];
  • of Frog, [485];
• Pelobates, branchial apertures of, [136];
  • vertebral column of, [556];
• Pelodytes, branchial chamber of, [135]
• Pelvic girdle, [606];
  • of Fishes, [606];
  • Amphibia and Amniota, [607];
  • of Lacertilia, [607];
  • of Mammalia, [608];
  • comparison with pectoral, [608];
• Penis, development of, [727]
• Peribranchial cavity, of Amphioxus, [7];
  • of Ascidia, [18];
  • Pyrosoma, [24];
• Pericardial cavity, of Pyrosoma, [26];
  • Elasmobranchii, [49];
  • Petromyzon, [94];
  • general account of, [626];
  • of Fishes, [627];
  • of Amphibia, Sauropsida and Mammalia, [628];
• Perichordal formation of vertebral column, [556]
• Perilymph of ear, [523]
• Periotic capsules, ossifications in, [595], [596]
• Peripatus, nervous system of, [409];
  • eye of 480;
  • excretory organs of, [688];
• Peritoneal membrane, [626]
• Petromyzon, development of, [83];
  • affinities of, [83], [84];
  • general development of, [87];
  • hatching of, [89];
  • comparison of gastrula of, [280];
  • branchial skeleton of, [312], [572];
  • cerebellum of, [425];
  • pineal gland of, [434];
  • pituitary body of, [436];
  • cerebrum of, [439];
  • auditory organ of, [517];
  • olfactory organ of, [533];
  • comparison of oral skeleton of with Tadpole, [586];
  • pericardial cavity of, [627];
  • abdominal pores of, [626];
  • venous system of, [651];
  • excretory organs of, [700];
  • segmental duct of, [700];
  • pronephros of, [700];
  • mesonephros of, [700];
  • thyroid body of, [760];
  • postanal gut of, [774];
  • stomodæum of, [775];
• Phosphorescence of larvæ, [364]
• Phylogeny, of the Chordata, [327];
  • of the Metazoa, [384]
• Pig, placenta of, [251];
  • mandibular and hyoid arches of, [589];
• Pineal gland, of Petromyzon, [93];
  • Chick, [175];
  • general development of, [432];
  • nature of, [432], [434];
• Pipa, brood-pouch of, [121];
  • metamorphosis of, [139];
  • yolk-sack of, [140];
  • vertebral column of, [556];
• Pituitary body, of Rabbit, [231];
  • general development of, [435];
  • meaning of, [436];
  • Placenta, of Salpa, [29];
  • Elasmobranchii, [66];
  • of Mammalia, [232];
  • villi of, [235];
  • deciduate and non-deciduate, [239];
  • comparative account of, [239]-259;
  • characters of primitive type of, [240];
  • zonary, [248];
  • non-deciduate, [250];
  • histology of, [257];
  • evolution of, [259];
• Placoid scales, [395]
• Planorbis, excretory organs of, [681]
• Planula, structure of, [367]
• Pleural cavities, [631]
• Pleuronectidæ, development of, [80]
• Pneumatocoela, characters of, [327]
• Polygordius, excretory organs of, [684]
• Polyophthalmus, eye of, [479]
• Polypedates, brood-pouch of, [121]
• Polyzoa, excretory organs of, [682];
  • generative cells of, [745];
  • generative ducts of, [751];
• Pons Varolii, [426], [427]
• Pori abdominales, Ammocoetes, [99]
• Porifera, ancestral form of, [345];
  • development of generative cells of, [741];
• Portal vein, [653]
• Postanal gut of Elasmobranchii, [58], [59], [60];
  • Teleostei, [75];
  • Chick, [169];
  • general account of, [323], [772];
• Præmaxilla, [594]
• Præopercular bone, [593]
• Præoral lobe, ganglion of, [377], [380]
• Prefrontals, [597]
• Presphenoid region of skull, [570]
• Primitive groove of Chick, [155]
• Primitive streak, of Chick, [152], [161];
  • meaning of, [153];
  • origin of mesoblast form in Chick, [154];
  • continuity of hypoblast with epiblast at anterior end of, in Chick, [156];
  • comparison of with blastopore, [165];
  • fate of, in Chick, [165];
  • of Lacerta, [203];
  • of Rabbit, [221];
  • of Guinea-pig, [223];
  • fusion of layers at, in Rabbit, [224];
  • comparison of with blastopore of lower forms, [226], [287];
  • of Mammalia, [290];
• Processus falciformis of Ammocoetes, [498];
  • of Elasmobranch, [502];
  • of Teleostei, [503];
• Proctodæum, [778]
• Pronephros, of Teleostei, [78], [701];
  • Petromyzon, [95], [99], [700];
  • Acipenser, [106], [110];
  • Amphibia, [134], [707];
  • general account of, [689];
  • of Cyclostomata, [700];
  • of Myxine, [701];
  • Ganoidei, [705];
  • of Amniota, [714];
  • of Chick, [718];
  • summary of and general conclusions as to, [728];
  • relation of, to mesonephros, [731];
  • cause of atrophy of, [729];
• Prootic, [596], [597]
• Propterygium, [616]
• Proteus, branchial arches of, [142]
• Protochordata, characters of, [327]
• Proto-ganoidei, characters of, [328]
• Proto-gnathostomata, characters of, [328]
• Proto-pentadactyloidei, characters of, [329]
• Protovertebrata, characters of, [328]
• Pseudis, Tadpole of, [139];
  • vertebral column of, [556];
• Pseudophryne, yolk-sack of, [140];
  • Tadpole of, [140];
• Pterygoid bone, of Teleostei, [581];
  • origin of, [597];
• Pterygoquadrate bar, of Elasmobranchii, [576];
  • of Teleostei, [581];
  • Axolotl, [584];
  • Frog, [584];
  • of Sauropsida, [588];
  • of Mammalia, [589];
• Pulmonary artery, origin of, [645];
  • of Amphibia, [645];
  • of Amniota, [649];
• Pulmonary vein, [655]
• Pupil, [489]
• Pyrosoma, development of, [23]

• Quadrate bone of Teleostei, [581];
  • of Axolotl, [584];
  • Frog, [585];
  • Sauropsida, [588];
• Quadratojugal bone, [594]

• Rabbit, development of, [214];
  • general growth of embryo of, [227];
  • placenta of, [248];
• Radiate symmetry, passage from to bilateral symmetry, [373]-[376]
• Raja, caudal vertebræ of, [553]
• Rat, placenta of, [242]
• Recessus labyrinthi, [519]
• Reissner’s membrane, [524]
• Reptilia, development of, [202];
  • viviparous, [202];
  • cerebellum of, [426];
  • infundibulum of, [431];
  • pituitary body of, [436];
  • cerebrum of, [439];
  • vertebral column of, [556];
  • arterial system of, [648];
  • venous system of, [656];
  • mesonephros of, [713];
  • testicular network of, [723];
  • spermatozoa of, [747];
• Restiform tracts of Elasmobranchii and Teleostei, [425]
• Retina, histogenesis of, [490]
• Retinulæ, [482]
• Rhabdom, [482]
• Rhinoderma, brood-pouch of, [121];
  • metamorphosis of, [139];
• Ribs, development of, [560]
• Rosenmüller’s organ, [725]
• Rotifera, excretory organs of, [680]
• Round ligament of liver, [663]
• Ruminantia, placenta of, [253]

• Sacci vasculosi, [437]
• Sacculus hemisphericus, [519];
  • of Mammals, [519], [520];
• Sagitta. _See_ ‘Chætognatha’
• Salpa, sexual development of, [29];
  • asexual development of, [33];
• Salamandra, larva of, [142];
  • vertebral column of, [553];
  • limbs of, [619];
  • mesonephros of, [708];
  • Müllerian duct of, [710];
• Salmonidæ, hypoblast of, [71];
  • generative ducts of, [704];
• Sauropsida, gastrula of, [286];
  • meaning of primitive streak of, [288];
  • blastopore of, [289];
  • mandibular and hyoid arches of, [588];
  • pectoral girdle of, [601];
• Scala, vestibuli, [522];
  • tympani, [523];
  • media, [522];
• Scales, general development of, [396];
  • development of placoid scales, [395];
• Scapula, [599]
• Sclerotic, [488]
• Scrotum, development of, [727]
• Scyllium, caudal vertebræ of, [553];
  • mandibular and hyoid arches of, [578];
  • pectoral girdle of, [600];
  • limbs of, [610];
  • pelvic fin of, [614];
  • pectoral fin of, [615];
• Segmental duct, [690];
  • development of in Elasmobranchs, [690];
  • of Cyclostomata, [700];
  • of Teleostei, [701];
  • of Ganoidei, [704], [705];
  • of Amphibia, [707];
  • of Amniota, [713];
• Segmental organs, [682]
• Segmental tubes, [690];
  • development of in Elasmobranchs, [691];
  • rudimentary anterior in Elasmobranchs, [693];
  • development of secondary, [731];
• Segmentation cavity, of Elasmobranchii, [42]-44;
  • Teleostei, [69], [85], [86];
  • Amphibia, [122], [125];
• Segmentation, meaning of, [331]
• Segmentation of ovum, in Amphioxus, [2];
  • Ascidia, [9];
  • Molgula, [22];
  • Pyrosoma, [23];
  • Salpa, [30];
  • Elasmobranchii, [40];
  • Telostei, [69];
  • Petromyzon, [84];
  • Acipenser, [102];
  • Lepidosteus, [111];
  • Amphibia, [122], [124];
  • Newt, [125];
  • Chick, [146];
  • Lizard, [202];
  • Rabbit, [214];
• Semicircular canals, [519]
• Sense organs, comparative account of development of, [304]
• Septum lucidum, [443]
• Serous membrane, Lacerta, [209];
  • of Rabbit, [237];
• Seventh nerve, development of, [459]
• Shell-gland of Crustacea, [689]
• Shield, embryonic, of Chick, [151];
  • of Lacerta, [202];
• Simiadæ, placenta of, [247]
• Sinus rhomboidalis, of Chick, [162]
• Sinus venosus, [637]
• Sirenia, placenta of, [255]
• Sixth nerve, [463]
• Skate, mandibular and hyoid arches of, [577]
• Skeleton, elements of found in Vertebrata, [542]
• Skull, general development of, [564];
  • historical account of, [564];
  • development of cartilaginous, [566];
  • cartilaginous walls of, [570];
  • composition of primitive cartilaginous cranium, [565];
• Somatopleure, of Chick, [170]
• Spelerpes, branchial arches of, [142]
• Spermatozoa, of Porifera, [741];
  • of Vertebrata, [746];
• Sphenoid bone, [595]
• Sphenodon, hyoid arch of, [588]
• Spinal cord, general account of, [415];
  • white matter of, [415];
  • central canal of, [417], [418];
  • commissures of, [417];
  • grey matter of, [417];
  • fissures of, [418];
• Spinal nerves, posterior roots of, [449];
  • anterior roots of, [453];
• Spiracle, of Elasmobranchii, [62];
  • Acipenser, [105];
  • Amphibia, [136];
• Spiral valve. _See_ ‘Valve’
• Spleen, [664]
• Splenial bone, [595]
• Squamosal bone, [593]
• Stapes, [529];
  • of Mammal, [590];
• Sternum, development of, [562]
• Stolon of Doliolum, [29];
  • Salpa, [33];
• Stomodæum, [774]
• Stria vascularis, [524]
• Styloid process, [591]
• Subintestinal vein, [651];
  • meaning of, [651];
• Syngnathus, brood-pouch of, [68]
• Subnotochordal rod, of Elasmobranchii, [54];
  • Petromyzon, [94];
  • Acipenser, [110];
  • Lepidosteus, [115];
  • general account of, [754];
  • comparison of with siphon of Chætopods, [756];
• Subzonal membrane, [237];
  • villi of, [236];
• Sulcus of Munro, [432]
• Supraclavicle, [600]
• Suprarenal bodies, [664]
• Supra-temporal bone, [593]
• Swimming bladder, _see_ Air bladder
• Sylvian aqueduct, [428]
• Sylvian fissure, [444]
• Sympathetic ganglia, development of, [467]

• Tadpole, [134], [139], [140];
  • phylogenetic meaning of, [137];
  • metamorphosis of, [137];
  • meaning of suctorial mouth of, [585];
• Tail of Teleostei, [80];
  • Acipenser, [109];
  • Lepidosteus, [109];
  • Amphibia, [132];
• Tarsus, development of, [620]
• Teeth, horny provisional, of Amphibia, [136];
  • general development of, [776];
  • origin of, [777];
• Teleostei, development of, [68];
  • viviparous, [68];
  • comparison of formation of layers in, [286];
  • restiform tracts of, [425];
  • mid-brain of, [425];
  • infundibulum of, [431];
  • cerebrum of, [439];
  • nares of, [534];
  • lateral line of, [538];
  • notochord and membrana elastica of, [549];
  • vertebral column of, [553];
  • ribs of, [561];
  • hyoid and mandibular arches of, [579];
  • pectoral girdle of, [601];
  • pelvic girdle of, [606];
  • limbs of, [618];
  • heart of, [637];
  • arterial system of, [645];
  • muscle-plates of, [670];
  • excretory organs of, [701];
  • generative ducts of, [704], [735], [749];
  • swimming bladder of, [763];
  • postanal gut of, [774];
• Teredo, nervous system of, [414]
• Test of Ascidia, [14];
  • Salpa, [31];
• Testicular network, of Elasmobranchs, [697];
  • of Amphibia, [712];
  • Reptilia, [723];
  • of Mammals, [724];
• Testis of Vertebrata, [746]
• Testis, connection of with Wolffian body, in Elasmobranchii, [697];
  • in Amphibia, [710];
  • in Amniota, [723];
  • origin of, [735];
• Thalamencephalon of Chick, [175];
  • general development of, [430];
• Third nerve, development of, [461]
• Thymus gland, [762]
• Thyroid gland, Petromyzon, [92];
  • general account of, [759];
  • nature of, [760];
  • development of in Vertebrata, [761];
• Tooth. _See_ ‘Teeth’
• Tori semicirculares, [428]
• Tornaria, [372]
• Trabeculæ, [565], [567];
  • nature of, [568];
• Trachea, [766]
• Trematoda, excretory organs of, [681]
• Triton alpestris, sexual larva of, [143]
• Triton, development of limbs of, [619];
  • urinogenital organs of, [712];
• Truncus arteriosus, [638];
  • of Amphibia, [638];
  • of Birds, [639];
• Tunicata, development of mesoblast of, [293];
  • test of, [394];
  • eye of, [507];
  • auditory organ of, [530];
  • olfactory organ of, [532];
  • generative duct of, [749];
  • intestine of 767;
  • postanal gut of, [771];
  • stomodæum of, [775];
• Turbellaria, excretory organs of, [681]
• Tympanic annulus of Frog, [587]
• Tympanic cavity, of Amphibia, [135];
  • Chick, [180];
  • Rabbit, [232];
  • general development of, [528];
  • of Mammals, [591];
• Tympanic membrane, of Chick, [180];
  • general development of, [528];
• Tympanohyal, [591]

• Umbilical canal of Elasmobranchii, [54], [57], [58], [59]
• Umbilical cord, [238];
  • vessels of, [239];
• Ungulata, placenta of, [250]
• Urachus, [239], [726]
• Ureters, of Elasmobranchii, [696];
  • development of, [723];
• Urethra, [727]
• Urinary bladder of Amphibia, [712];
  • of Amniota, [726];
• Urinogenital organs, _see_ Excretory organs
• Urinogenital sinus of Petromyzon, [700];
  • of Sauropsida, [726];
  • of Mammalia, [727];
• Urochorda, development of, [9]
• Uterus, development of, [726];
  • of Marsupials, [726];
• Uterus masculinus, [726]
• Utriculus, [519]
• Uvea of iris, [489]