614 



INDEX 



Trembley. 141 



Tremex columba, 291 



Trepang, 207 



Trial and error, 73-74 



Priassic period, 511, 514, 515 



Triaxon spicules, 130, 131 



Trichinella, 178, 180 



Trichinella spiralis, 180 



Trichinosis, 180 



Trichocysts, 70, 74 



Trihybrids, 533 



Trilobites, 303, 513, 614 



Trinomials, 543 



Triploblastic condition, 121, 155, 164, 544, 545, 



547 

 Triradiate spicules, 130, 131 

 Trivium, 200 

 Trochelminthes, 185 

 Trochophore, 225, 226, 241, 248 

 Trochozoon, 226 

 Trombiculn irritans, 301 

 Trophoderm, 418, 419 

 Trophozoite, 86 

 Tropisms, 54, 55 



{See individual tropisms) 

 Trunk fishes, 348 

 TrypanosoTna gamhiense, 80 

 Trypanosomes, 87 

 Trypanosomiasis, 87 

 Trypsin, 323 

 Tsetse fly, 87 

 Tuatara, 387 



Tube-dwelling worms, 184, 243, 244 

 Tube feet, 192-197, 201-204, 206 

 Tuberculosis, 288, 488, 490 

 Tubipora, 152 



Tubular nervous system, 306, 308, 445 

 Tundra, 507-509 

 Tunic, 310 



Tunicates, 308-314, 442 

 Turbellaria, 164, 165, 467 

 Turbinate bones, 329 

 Turkeys, 402, 405 

 Turtles, 334, 380, 388, 389, 417, 481, 520 



heart, 379 

 Tusk shells, 217, 221 

 Tusks, 523 

 Tussock moth, 285 

 'Tween-brain, 328 

 Twins, 538-539 



Tympanic membrane, 278, 330, 331, 362, 364 

 Tympanum, 272, 278, 330, 33! 

 Tyndall, 26, 554 

 Types, 546 

 Typhoid fever, 288, 491 



U 



Ulna, 319, 321, 3G1, 388, 391 



Umbilical cord, 418, 420, 421 



Umbo, 208, 209 



Uncinate process, 393 



Undulating membrane, 71, 83 



Unequal cleavage, 116, 118, 214, 225, 236, 371, 449 



Unguiculata, 411, 412 



Ungulata, 411, 416 



Uniformitarianism, 553 



Unio complanatus, 214 



Unios, 214-216 



Uniparental reproduction, 105 



Units, hereditary, 527, 529 



Universal symmetry, 51 



Unpaired genes, 534 



Urea, 36, 323 



Ureters, 210, 213, 317, 325, 326 



Urethra, 325 



Urinary bladder, 317, 325 



Urinogenital sinus, 352 



Urochordata, 308, 310, 547 



Urodela, 364, 365 



Urogleyia, 81 



Uroglenopsis americana, 80 



Uropods, 251, 252 



Urosalpinx, 225 



Use and disuse, 517, 521 



Uses of foods, 38, 454-455 



Uterus, 160, 161-168, 176, 325, 341, 371, 419 



Utriculus, 330, 331 



Vaccination, 491 



Vaccines, 491-492 



Vacuoles, 30, 64, 65, 67, 70, 71, 79, 85. 86, 127, 460 



Vagina, 160, 161 



Vagus nerves, 431 



Valves, blood vessels, 231, 254, 552 

 oral, 362, 353 

 spiral, 338, 339 



Vampire bats, 505 



Vane, 392 



Variation, 518, 521 



Varieties, 58, 543 



Vas deferens, 160, 161, 166, 168, 213, 235, 252, 

 263, 333 



Vasa efferentia, 160, 161, 166, 235, 325 



Vascular systems, air-vascular (see Tracheae) 

 blood-vascular (aee Circulatory system) 

 gastro-vascular (see Gastro-vascular cavity) 

 water-vascular (see Water -vascular system) 



Vegetal pole, 118, 371 



Vegetation regions, 507-509 



Veins, 274, 298, 324, 551, 552 



Velum, 143, 150, 226, 311, 313, 314 



Velvet mites, 302 



Vena cava, 210, 213, 409 



Venomous snakes, 385-387 



Ventral aorta, 340 



Ventral fins, 348 



Ventral line, 176 



Ventral nerve cord, 176, 231, 233, 252, 254, 276, 

 277 



Ventral root, 327, 32S 



Ventral sucker, 371, 372, 373 



Ventral vessel, 231 



Ventricle, 210, 339, 340, 361, 379, 380 



Ventriculus, 277 



Venus' flower basket, 129 



Venus' girdle, 155 



Vermes, 183 



