INDEX. 



Acraniates, 393, 396, 405 



appendages, 398 



circulation, 401 



degeneration, 399 



development, 401 



heart, 401 



mantle, 400 



metamerism, 398 



nervous system, 399 



sexual organs, 401 



skeleton, 400 

 Amphibia, 386 

 Amphioxus, 393 

 Anal frill, 371 

 Anaspida, 364 

 Annelids, 403 

 Antiarcha, 367 

 Appendages, invaginated, 275 



locomotor, 249, 268 



respiratory, 264 



sequence of functions of, 271 

 Archenteron, 248 

 Arches, neural, 307 

 Arthro-dira, 386, 388 

 Aspidocephali, 358 

 Asymmetry, as creative factor 458 

 Ateleaspidae, 363 

 Atrial, folds, 31 



frill, 371 

 Auditory organ, 120 



pit- 39 



Balancers, 261 

 Bdellostoma, oral lobes, 260 

 Birkeniida?, 364 

 Blastopore, 243-404 

 Bothroidal cord, 328 

 Bothriolepis canadensis, 367 



atrial frill, 371 



cephalic appendages, 376 



exoskeleton, 367 



eyes, 375 

 food, 379 



giUs, 37 ! 



hyoid arches, 375 



locomotion, 379 



mandibles, 374 



mode of preservation, 377 



mouth, 375 



olfactory organs, 375 



premaxilla?, 373 



preoral chamber, 373 



sensory grooves, 376 



viscera, 372 

 Brain, function of, 174 



meaning of term, 41 



minute structure of, 71 

 Branchial cartilages, 306 



Branchial neuromeres, 67, 71 



warts, 115 



Branchiencephalon, 67, 69 

 Branchiocephalon, 20 

 Brachiopods, 445 

 Branchipus, 16 

 Bunodes, 29 



Canalis cen trails, 331 

 Capsuligenous bars, 316 

 Cardiac ganglion, 202 

 Cardinal veins, 199 

 Cartilage, branchial, 307 



neural, 306 

 Caudal navel, 243 

 Cement organ, of polypterus, 262 

 Cephalaspidre, 358 

 Cephalization, 26, 254 

 Cephalic functions, arrangement of, 8 

 Cephalic navel, 25, 250 

 Cephalogenesis, in arachnids, 5 



in arthropods, 3 

 Cephalodiscus, 439 

 Cerebellum, 19 

 Cerebral hemispheres, 54 

 Chaetognatha, 448 

 Cheliceral lobes, 59 



neuromere, 59, 62 

 Chewing' apparatus, 188 

 Choroid fissure, 151 



plexus, 19 

 Circle of Willis, 199 

 Circulation, 198 

 Cirri peds, 408 

 Coccosteus, 388 

 Ccelom, 407, 426 

 Ccelomic chamber, 23 

 Ccelolepidae, 364 



Commissures, 43, 60, 72, 79, 80, 90 

 Concrescence, 25, 243-404 

 Cord, minute structure of, 71 

 Cornua, 40 

 Cranial flexure, 40 



ganglia, 17 



Craniates, 393-395. 403 

 Creative factor, asymmetry as, 458 



brain as, 461 



chiten as, 459 



exoskeleton as, 459 



yolk sphere as, 461 

 Cyclostomata, 383 



Degeneration, 277-279, 280, 281, 288 



Denticles dermal, 303 



Dentine, 304 



Dermal skeleton, 289 



Dicephalon, 15 



Diencephalon. 18, 57, 58 



483 



