Thalasiochelys, stomach, 257 

 Thecal cells, 321 

 Thecodont teeth, 71, 249 

 Thelodui. Thelodontii, 19, 231 

 Therapsids, 22, 76, 343, 446 

 Thoracic vertebrae, 141, 142, 142. 149 



number, 141, 145 

 Thread cells, 226 

 Thrombocytes, 377 

 Thymus, 378, 380, 381, 382 

 Thyroid gland, 280, 354, 379, 382 



duct of, 380 



origin of, 199 

 Thyroid cartilage, 53 

 Thyroid vein, 360 

 Thyrolaryngeal artery, 359 

 Thyrohyal, 41 

 Toad, see Bnfo 

 Tollichtkys, bone, 232 

 Tome's process, 245 

 Tonsils, 378 

 Tongue, 253 



(rasping organ) skeleton, 132 

 Tongue bar, 11,/-^ 

 Tooth, 217, 242 



development, 244 



labyrinthodont, 248, 250 



mammal, 2-f5 



milk and permanent, 242, 251 

 Tooth plate, 23. 123, 131 

 Tornaria, tornaria larva, 12, 16 _ ^ 



Torpedo, 119, 204, 286, 310, 372, 373, 418~"-~" 

 Trabecles, trabeculae, 53, 64, 80, 107,4-21, 



128, 131 

 Trabecula communis, 53, 108 



cornual process, 132 



rostral process, 122 

 Trabeculae of bone, 76 

 Trabeculae of connective tissue, 314 

 Trabeculae carnae, 344 

 Trachea, 253, 280 



Transverse canal, vertebral canal, 141 

 Transverse process, 141, 142, 143, 145, 146, 



147, 149, 152, 153 

 Transverse septum, 280 

 Transverse sinus, 360 

 Trapezium, 172, 424, 432, 433 



pars clavotrapezius, 424, 432 



pars spinotrapezius, 432 



pars spinotrapezius anterior, 424 



pars spinotrapezius posterior, 424 

 Trapezoideum, 172 



Tremalaspis, Tremataspids, 19, 30, 30, 31, 

 229,411, 412 



bone, 231 



head and trunk armor, 135 

 Trematops, 1 78 

 Triangular, 172 



Triassic, 62, 85, 113, 115, 123, 156 

 Triassocheiys, 250 

 Triceps, 426, 436 



pars anconeus. 426 



epitrochleo-anconeus, 426 



lateralis, 426, 433 



longum, 426, 433 



medialis, 426, 433 

 Trichosums, 173, 293, 362 



Trigeminal-facial canal, see lateral canal 

 Trigeminal ner\'e (V), 49, 386 

 Trigemino-facio-abducens foramen, 122 

 Triquetrum, 172 

 Tnlon, 257, 299 

 Trochlear nerve (IV), 386 



decussation, 394 

 Trophoblast, 208 

 Truncus arteriosus, 339 

 Trunk armor, 184 

 TrygoJi, 286 



Tuatara, see Sphenodon 

 Tube division of Miillerian duct, 325 

 Tuber cinereum, 384 

 Tubercles of bony plates, 229 

 Tuberculum, rib head, 148 

 Tuberculum impar, 394 

 Tubular glands, 218 

 Tubular vertebra, 150 

 Tubuli mesonephroi, 318 

 Tubulodentine, 123, 228 

 Tubulus rectus, 318 

 Tunic, 9 



cells, 1 1 

 Tunica albuginea, 318 

 Tunicate, \\J97 

 y Tunicin, 1 1 

 ; Tupinambis (Tegu), 22, 64, 66, 146, 174, 175, 

 176, 249, 250, 251, 256, 259, 260, 281, 

 282. 341 



head skeleton, 61, 65, 66 

 .:^' heart, 341 



hyoid apparatus and columelle, 67 



pectoral girdle, 173, 174, 175 



vertebrae, 146 

 Turbinals, 40, 44, 53 

 Turkey, 364 

 Tmsiops, 257 



Turtle, 22, 28, 61, 91, 259, 260, 280, 363, 

 381,403,423 



digestive tract, 259, 262 



head skeleton, 66, 72 



penis, 324 



urogenital system, 296 

 Tusk, 86 

 Tympanic bone. 40, 46, 59, 60 



homolog of angular, 41 

 Tympanic bulla, 37 

 Tympanic fenestra, 37 

 Tympanic fossa, 49, 51 

 Tympanic membrane, 2S, 37, 40, 406 

 Tympanic notch, 85, 89, 407 

 Tympanic ring, 76 

 Tympanohyal process, 49 

 Tympanum, 406 

 Typhlonectes, 326 

 Typhlosole, 264, 276 



Ulna, 171 



Ulnare, 172 



Ultimobranchial body, 380, 381 



Umbilicus. 203 



Uncinate processes. 148, 149 



Uiidma, 156 



Uniformitarianism, 2 



Unilobular, or unipyramidal, 291, 292, 292 



Unipolar odontoblasts, 228 



Unipyramidal, see unilobular 



Uranoscopidae, 420 



Ureter, 291,296, 300,302 



Urethra, 293. 318 



Urinary bladder, 256 



Urinary sinus, 304 



Urinary vesicle, 382 



Urochordata (Tunicates), urochordates, 9, 



19,291 

 Urodeles, 79, 104, 155, 325, 326 



aortic arches, 349 



development of gonadal ridge, 326 

 Urodeum, 257 

 Urogenital gland, 335 

 Urogenital sinus, 297, 318 

 Urogenital system, 298, 323 

 Urohyal (urobranchial), 96, 107 

 Uromastix, 66 

 Uronemus, 169 

 Urostyle, 153, 168 

 Uterus, 320, 325 



types of, 323 

 Utriculus, 406 



Vacuolate cells, notochord, 1 1 



Vagal lobe, 394 



Vagina, 320, 325 



Vagina masculina, 334 



Vagoaccessory nerve (X-XI), 391 



Vagus nerve (X), 284, 387 



Valve, of respiratory pharynx, 275 



Valves of truncus, distal and proximal, 343, 



344 

 Valvula cerebelli, 394 

 VAN WIJHE, 380 

 Varanm, 146, 296, 347, 348, 422 

 Vas deferens, ductus deferens, 294, 297, 300, 



312,318 

 Vascular canals, bone, 228 

 Vasodentine, 228, 248 

 Vastus intermedins, 430 

 Vastus lateralis, 428 

 Vastus medialis, 429 

 Vegetal pole, 193, 194 

 Velar cartilage, 130 

 Velar chamber, 277 

 Velar sinus, 366 

 Velar tentacle, 275 

 Velum, 5, 197, 199 

 Velum transversum, 384, 388 

 Vena capitis lateralis, 362 

 Vena capitis medialis, 362 

 Ventral abdominal vein, 370 

 Ventral aorta, 347 

 Ventral blood vessel. 16 

 Ventral (sensory-canal) body lines. 410 

 Ventral bronchi, 281 

 Ventral cleithral plate. 184 

 Ventral (hypochordal) fin lobe, 168 

 Ventral jugular sinus, 365 

 Ventral nerve cord, 9, 12, 14, 16 

 Ventral rib, 188 

 Ventricle, of heart, 339, 383 

 Ventricle, of nerve tube, 9 

 Vermiform appendix, 253 



INDEX 



477 



