Amnurus, 393, 404 

 Ameloblasts, 245 



Amta, 20, 115, 161, 162, 167, 168, 181, 182, 

 236, 237, 271, 288, 304, 308, 309, 331, 

 332, 345, 350, 351, 359, 365, 372, 378, 

 382, 394, 415, 416, 423, 447, 448 

 aortic arches, 351 

 bone structure, 237 

 cranial nerves, 395 

 development of, 207 

 digestive tract, 270, 270 



development, 272 

 external appearance, 25 

 fin base, 185 

 head skeleton, compared with Lepisosteus, 



117, 118 

 kidney, 308, 309 

 pectoral girdle, 184 

 reproductive system, 329 

 sensory-canal system, 415 



development, 416 

 swim bladder, 284, 285 

 vertebrae, 160, 160, 161 

 Amnion, 203, 208 

 Amniotes, 22, 402, 407 

 Amniotic cavity, 203 

 Amphiarthroses, 41 

 Amphiaspids, 41 1 

 Amphibamus, 85, 152 

 Amphibian papilla, 406 



Amphibians (see also Cryplobranchus, Necturus, 

 Rana), 21, 79, 192', 211, 290, 381, 394, 

 402, 407, 423, 448 

 aortic arches, 349, 350 

 arteries 

 head, 356 

 body, 367 

 brain, 388 



digestive tract, 262, 264 

 endolymphatic sac, 408 

 external appearance, 27 

 gills, 286 

 head skeleton, 80 



development, 80 

 heart, 343 



development, 344 

 lungs, 281 

 muscles 

 eye, 422 

 forelimb, 433 

 origin of, 104 

 pineal eye, 405 



reproductive system, 325, 326, 326 

 sensory-canal system, 416 

 skin, 222 

 teeth, 248 



venous system, 364, 369, 371 

 vertebrae, 151 

 Amphicoelous vertebrae, 148, 150, 155 

 Amphioxus, 5, 201, 218, 291, 318, 377, 380, 

 382, 405 

 anatomy, 5, 6', 7, 8 

 development, 194, 194, 195, 196, 421 

 larva, 6, 196 

 life habit, 6" 

 myomere, 42! 



skin, 218 

 Amphiplatyan vertebra, 148, 150 

 Amphistylic jaw suspension, 119 

 Ampulla, definition, 1 1 



of Lorenzini, 23, 410, 418 

 of nephric duct, 301, 318 

 of semicircular canal, 406 

 of Vater, 253 

 Anabteps, 329 

 Anal fin, 166 

 Anaspids, 19, 31, 66, 89, 135, 170, 186, 240 



head skeleton of, 137 

 Ancestral vertebrae, structure of, 16, 17 

 Anguilla, skin, 225 



stomach, 257 

 Angular, 76, 85, 106 



homolog of tympanic, 41 

 origin in teleost, 11 1 

 process of mandible, 41, 44 

 Animal pole, 193, 194 

 Annular cartilage, 130 

 Anocleithrum, 179 

 Ansa coli, 255 

 Anteater, 323 



Anterior cardinal, 339, 361 

 Anterior cerebral artery, 354 

 Anterior commissure, 383, 384, 393 

 Anterior basicapsular commissure, 107, 131 

 Anterior facial vein, 361 

 Anterior jugular vein, 361 

 Anterior lacerate fissure, 49 

 Anterior lateral cartilage, 130 

 Anterior lateral field, 136 

 Anterior medial gular, 106 

 Anterior myodome, 107, /// 

 Anterior narial opening, 37 

 Anterior neuropore, 195 

 Anterior pelvic clasper, 24 

 Anterior pit line, 410 

 Anterior (ascending) process of supraoccipi- 



tal, 69 

 Anterior tectal cartilage, 130 

 Anterior transverse lamina, 53 

 Anterior vena cava, 340, 360 

 Anterior vestibular center, 121 

 Anthracosaur, 86, 177 



Antiarchs (see also Arthrodires), 20, 126, 

 186 

 head skeleton of, 127, 127 

 pectoral fins, 190 

 Antibrachium, 427 

 Antilocapra, horn, 220 

 Antotic pillar, 71, 80, 131 

 Antrum, 324 

 Anura, anuran (see also Rana), 28, 79, 82 



104, 155, 249, 325, 390 

 Anus, 8, 12, 197, 199, 201, 205 

 at position of blastopore, 205 

 Aortae, paired, 8 



Aortic arches, 339, 347, 347, 348, 349 

 Aortic canal in basic cranii, 114 

 Aphetohyoidean, 126, 289 

 Apical cartilage, 131 

 Aplesodic fin, 240 

 Apoda, 28, 79, 155 



gonadal ridge, development, 326 



skin and scales, 224 

 Aponeurosis, 424 

 Appalachian revolution, 63 

 AppendictUana, 9 

 Appendix, 319 

 Apteria, 222 



Apleryx, external appearance, 29 

 Aqueduct of Sylvius, 383 

 Arapaima, scale, 238 

 Archaeapleryx, 22, 76, 79 

 Archaeornts, 76 

 Archegosaurus, 152 

 Archenteron, 195, 199, 208 

 Archeria, pelvic girdle, 176 

 Archeozoic, 63 

 Archicentrous vertebra, 166 

 Archipallium, 388 

 Archipterygium, 178, 180, 183 

 Archodus, 246, 444 

 Archosauria, 61, 71 

 Arciferal (arciferous), 177, 191 

 Arctolepid, trunk armor, 190 

 Arcualia, 162 



blastema, 149 

 Area pellucida, 201, 205 

 Area opaca, 201 

 Areolar tissue, 225 

 Armadillo, 323 

 Arteries, see specific artery 

 Arthrodires, 20, 184, 186, 192. 240, 290, 415 

 as chondrichthyes, 119 

 branchial skeleton, 289 

 fin rays, 243 

 head skeleton, 126 

 sensory-canal system, 411 

 teeth, 246 



trunk armor, evolution of, 190 

 Articular, 80, 83, 85, 106, 127 

 condyle, 1 19 

 part of malleus, 41 

 process of mandible, 41 

 Artiodactyles, 22, 291 

 Arytenoid, 280 

 Ascaphus, 156, 177, 178 

 Ascending esophageal artery, 348 

 Aspidin, 229 



Aslerolepis, pectoral fin, 190 

 Astragalus, 1 73 



Astraspu, astraspid, 19, 137, 229, 240, 411 

 Astroscopui, 420 

 Asymmetron, 5 

 Athrocytosis, 318 

 Atlantal foramen, 141 

 Atlas, 141, 142, 145, 146, 147, 149 

 Alopacanl/iiLs, jaw and teeth, 246, 246 

 Atrioventricular, cushion and valve, 339 

 Atrium, of heart, 339 

 Atrium, of Protochordates, 6, 9, 11, 197 

 Atubaria, 14, 16 

 Auditory nerve (VIII), 386 

 foramen, 122 

 placode, 406 

 Auerbach's plexus, 387 

 AULIE, 3 



Auricularia (or bipinnaria) larva of echino- 

 derm, 16 



460 . INDEX 



