IXDEX. 



653 



girdle of, 493 ; limbs of, 501 ; pelvic fin 

 of, 504 ; pectoral fin of, 504 



Segmental duct, 568 ; development of in 

 Elasmobranchs, 569 ; of Cyclostomata, 

 577 ; of Teleostei, 578 ; of Ganoidei, 580, 

 581; of Amphibia, 582; of Amniota, 

 588 



Segmental organs, 563 



Segmental tubes, 569 ; development of in 

 Elasmobranchs, 570 ; rudimentary an- 

 terior in Elasmobranchs, 571 ; develop- 

 ment of secondary, 602 



Segmentation cavity, of Elasmobranchii, 

 3436; Teleostei, 56, 69, 70; Amphibia, 

 100, 103 



Segmentation, meaning of, 274 



Segmentation of ovum, in Amphioxus, 2 ; 

 Ascidia, 8 ; Molgula, 18 ; Pyrosoma, 

 19; Salpa, 25; Elasmobranchii, 33; 

 Teleostei, 56 ; Petromyzon, 69 ; Aci- 

 penser, 84 ; Lepidosteus, 92 ; Amphibia, 

 100, 102; Newt, 103; Chick, 121; 

 Lizard, 167 ; Rabbit, 177 



Semicircular canals, 427 



Sense organs, comparative account of 

 development of, 252 



Septum lucidum, 365 



Serous membrane, Lacerta, 172 ; of Rabbit, 

 196 



Seventh nerve, development of, 377 



Shell-gland, of Crustacea, 568 



Shield, embryonic, of Chick, 125 ; of 

 Lacerta, 167 



Simiadffi, placenta of, 205 



Sinus rhomboidalis, of Chick, 134 



Sinus venosus, 524 



Sirenia, placenta of, 212 



Sixth nerve, 381 



Skate, maudibular and hyoicl arches of, 

 475 



Skeleton, elements of found in Vertebrata, 

 447 



Skull, general development of, 465 ; histo- 

 rical account of, 465; development of 

 cartilaginous, 466 ; cartilaginous walls 

 of, 470 ; composition of primitive car- 

 tilaginous cranium, 466 



Somatopleure, of Chick, 141 



Spelerpes, branchial arches of, 117 



Spermatozoa, of Porifera, 612 ; of Verte- 

 brata, 614 



Sphenoid bone, 489 



Sphenodon, hyoid arch of, 483 



Spinal cord, general account of, 342 ; 

 white matter of, 342 ; central canal of, 

 343, 345 ; commissures of, 343 ; grey 

 matter of, 343 ; fissures of, 344 



Spinal nerves, posterior roots of, 369 ; 

 anterior roots of, 372 



Spiracle, of Elasmobranchii, 50 ; Acipen- 



ser, 87; Amphibia, 112 

 Spiral valve. See ' Valve ' 



Spleen, 547 



Spleuial bone, 488 



Squamosal bone, 487 



Stapes, 436 ; of Mammal, 485 



Sternum, development of, 463 



Stolon of Dolioluni, 24 ; Salpa, 28 



Stomodfeurn, 636 



Stria vascularis, 431 



Styloid process, 486 



Sub-intestinal vein, 535 ; meaning of, 



535 



Syugnathus, brood-pouch of, 55 

 Subnotochordal rod, of Elasrnobranchii, 



45 ; Petromyzon, 77 ; Acipenser, 91 ; Le- 



pidosieus, 95 ; general account of, 620 ; 



comparison of with siphon of Chasto- 



pods, 622 



Subzonal membrane, 196 ; villi of, 195 

 Sulcus of Munro, 355 

 Supraclavicle, 492 

 Suprarenal bodies, 547 

 Supra-temporal bone, 4S7 

 Swimming bladder, see Air bladder. 

 Sylvian aqueduct, 352 

 Sylvian fissure, 365 

 Sympathetic ganglia, development of, 



384 



Tadpole, 111, 114, 115 ; phylogenetic 

 meaning of, 113 ; metamorphosis of, 

 113 ; meaning of suctorial month of, 

 481 



Tail of Teleostei, 64 ; Acipenser, 89 ; Le- 

 pidosteus, 97 ; Amphibia, 109 



Tarsus, development of, 509 



Teeth, horny provisional, of Amphibia, 

 112 ; general development of, 640 ; 

 origin of, 640 



Teleostei, development of, 55 ; viviparous, 

 55 ; comparison of formation of layers in, 

 238; restiform tracts of, 350; mid-brain 

 of, 352 ; infundibulum of, 355 ; cerebrum 

 of, 361 ; nares of, 440 ; lateral line of, 

 444 ; notochord and membrana elastica 

 of, 452 ; vertebral column of, 456 ; ribs 

 of, 463 ; hyoid and mandibular arches 

 of, 476 ; pectoral girdle of, 493 ; pelvic 

 girdle of, 498 ; limbs of, 507 ; heart of, 

 523 ; arterial system of, 530 ; muscle- 

 plates of, 552 ; excretory organs of, 578 ; 

 generative ducts of, 580, 605, 616 ; 

 swimming bladder of, 627; postanal 

 gut of, 636 



Teredo, nervous system of, 341 



Test of Ascidia, 12 ; Salpa, 26 



Testicular network, of Elasmobranchs, 574 ; 

 of Amphibia, 586 ; Reptilia, 596 ; of 

 Mammals, 596 



Testis of Vertebrata, 614 



Testis, connection of with Wolffian body, 

 in Elasmobranchii, 574 ; in Amphibia, 

 585 ; in Amniota, 596 ; origin of, 605 



ThalarneucephaVn of Chick, 145 ; general 

 development of, 354 



