644 



Arterial system of Petromyzon, 80 ; con- 

 stitution of in embryo, 529 ; of Fishes, 

 530 ; of Amphibia, 531 ; of Amniota, 

 532 



Arthropoda, head of, 260 ; nervous system 

 of, 337 ; eye of, 395 ; excretory organs 

 of, 567 



Articular bone of Teleostei, 478 ; of Sau- 

 ropsida, 484 



Ascidia, development of, 8 



Ascidians. See ' Tunicata ' 



Ascidiozooids, 21 



Atrial cavity of Amphioxus, 6 ; Ascidia, 

 15 ; Pyrosoma, 20 



Atiial pore of Amphioxus, 6 ; Ascidia, 17 ; 

 Pyrosoma, 23 ; Salpa, 27 



Auditory capsules, ossifications in, 489, 

 490 



Auditory involution of Elasmobranchii, 

 47 ; Teleostei, 59 ; Petromyzon, 73, 7G ; 

 Acipenser, 87 ; Lepidosteus, 94 ; Am- 

 phibia, 105 ; Chick, 141 



Auditory nerve, development of, 377 



Auditory organs, of Ascidia, 13 ; of Salpa, 

 26 ; of Ammoccetes, 80 ; Gauoidei, 89, 

 94 ; of Amphibia, 105 ; of Aves, 141 ; 

 general development of, 422 ; of aquatic 

 forms, 422 ; of land forms, 423 ; of 

 Ccelenterata, 423 ; of Mollusca, 424 ; of 

 Crustacea, 425; of Vertebrata, 425; of 

 Cyclostomata, 73, 76, 426 ; of Teleostei, 

 Lepidosteus and Amphibia, 426 ; of 

 Mammalia, 427 ; accessory structures of, 

 435 ; of Tunicata, 436 



Auriculo-ventricular valves, 528 



Autostylic skulls, 47(5 



Aves, development of, 120 ; cerebellum of, 

 351; midbrain of, 352; infuudibnlum 

 of, 355 ; pineal gland of, 357 ; pituitary 

 body of, 359 ; cerebrum of, 361 ; ol- 

 factory lobes of, 366 ; spinal nerves of, 

 374 ; cranial nerves of, 374 ; vagus of, 

 377 ; glossopharyngeal of, 377 ; verte- 

 bral column of, 459 ; ossification of 

 vertebral column of, 460 ; branchial 

 arches of, 472, 473 ; pectoral girdle of, 

 495 ; pelvic girdle of, 499 ; heart of, 

 523 ; arterial system of, 532 ; venous 

 system of, 541 ; muscle-plates of, 552 ; 

 excretory organs of, 588 ; mesonephros 

 of, 589 ; pronephros of, 591 ; Miillerian 

 duct of, 591, 593 ; nature of prone- 

 phros of, 594 ; connection of Miillerian 

 duct with "Wolffian in, 594 ; kidney of, 

 595 ; lungs of, 629 ; liver of, 632 ; post- 

 anal gut of, 636 



Axolotl, 117, 118 ; ovum of, 99 ; mid- 

 brain of, 352 ; mandibular arch of, 479 



Basilar membrane, 432 

 Basilar plate, 466 

 Basipterygium, 502 

 Basisphenoid region of skull, 469 

 Bilateral symmetry, origin of, 308 310 



Bile duct, 633 



Bladder, Amphibia, 108 ; of Amniota, 598 



Blastodermic vesicle, of Babbit, first 

 development of, 179 ; of 7th day, 183 ; 

 Guinea-pig, 219 ; meaning of, 242 



Blastoderm of Pyrosoma, 20; Elasmo- 

 brauchii, 34; Chick, 124; Lacerta, 167 



Blastopore, of Amphioxus, 2; of Ascidia, 

 9; Elasinobrauchii, 35, 44, 51; Petro- 

 myzon, 71; Acipenser, 86; Amphibia, 

 103, 108; Chick, 127; Babbit, 178; 

 true Mammalian, 187 ; comparative 

 history of closure of, 236, 240; sum- 

 mary of fate of, 281 ; relation of to 

 primitive anus, 268 



Blood-vessels, development of, 520 



Body cavity, of Ascidia, 18; Molgula, 18; 

 Salpa, 26; Elasmobranchii, 39; of Te- 

 leostei, 60; Petromyzon, 77; Chick, 

 140; development of in Chordata, 269 ; 

 vie\vs on origin of, 294 297, 310; of 

 Invertebrata, 512; of Chordata, 513; of 

 head, 557 



Bombinator, branchial chamber of, 112 ; 

 vertebral column of, 458 



Bonellia, excretory organs of, 567 



Bones, origin of cartilage bones, 447 ; 

 origin of membrane bones, 447; develop- 

 ment of, 448; homologies of membrane 

 bones, 487; homologies of cartilage 

 bones, 489 



Brachiopoda, excretory organs of, 563; 

 generative ducts of, 617 



Brain, of Ascidia, 10, 13; Elasmobran- 

 chii, 46, 48, 49; Teleostei, 62; Petro- 

 myzon, 73, 76; Acipenser, 87; Lepi- 

 dosteus, 93 ; early development of in 

 Chick, 141; flexure of in Chick, 145; 

 later development of in Chick, 146 ; 

 Rabbit, 190; general account of deve- 

 lopment of, 345; flexure of, 346; histo- 

 geny of, 347 



Branchial arches, prseoral, 470; disap- 

 pearance of posterior, 472 ; dental plates 

 of in Teleostei, 473; relation of to 

 head cavities, 471 : see 'Visceral arches' 



Branchial chamber of Amphibia. 112 



Branchial clefts, of Amphioxus, 6; of 

 Ascidia, 15, 17; Molgula, 19; Salpa, 

 27; of Elasmobranchii, 47, 48, 49, 50; 

 Teleostei, 62; Petromyzon, 74, 79; Aci- 

 penser, 87; Lepidosteus, 94, 96; Am- 

 phibia, 109, 110; Chick, 147; Babbit, 

 191 ; prreoral, 259, 265 ; of Inverte- 

 brata, 270; origin of, 270 



Branchial rays, 473 



Branchial skeleton, development of, 471, 

 486 ; of Petromyzon, 79, 259, 471 ; of Ich- 

 thyopsida, 472; dental plates of in Tele- 

 ostei, 473 ; relation of to head cavities, 

 471 



Branchia?, external of Elasmobranchii, 50, 

 51; of Teleostei, 62; Acipenser, 88; 

 Amphibia, 105, 110, 112 



