INDEX 



647 



Toads, 340, 365, 372-374, 381, 465 



horned, 391 

 Toes, 189, 373, 389, 404, 438, 439, 441, 423 

 Toleration, 517 

 Tongue, 328, 389, 390, 400 



cartilage, 342 

 Tonic contraction, 495 

 Tonsils, 425 

 Tonus, 210, 490, 495 

 Tooth, 427 



(See also Teeth) 

 Tornaria, 316 

 Tortoises, 388, 400, 401, 534 



(See also Turtles) 

 Total cleavage, 118, 120, 142, 476, 477 

 Toucans, 534, 535 

 Touch (see Tactile organs) 

 Toxins, 518 

 Trachea, 328, 330, 407 



Tracheae, 273, 274, 280, 281, 303, 304, 311, 468 

 Tracheal gills, 281, 468 

 system, 281 

 tubes, 308 

 Traction fibers, 49 

 Traumatism, 517 

 Tree frogs, 373 

 Tree toad.s, 373 

 Trematoda, 166-177 

 Trembley, 143 

 Tremex columba, 291 

 Trepang, 211 

 Trial and error, 73-74 

 Triassic period, 539, 541-543 

 Triaxon spicules, 132, 133 

 Trichinella, 183, 184 

 Trichinella spiralis, 183 

 Trichinosis, 183 

 Trichocysts, 70, 74 

 Trihybrids, 561 

 Trilobites, 309, 541, 542 

 Trinomials, 572 

 Triploblastic condition, 123, 574-576 



embryo, 123 

 Triradiate spicules, 132, 133 

 Trivium, 203 

 Trochelminthes, 188 

 Trochophore, 229, 230, 246, 254 

 of patella, 230 



Trochozoon, 230 



Tromhicula irritans, 307 



Trophoderm, 444, 445 



Trophozoite, 87 



Tropical region, 535 



Tropisms, 55, 56 



(See also individual tropisms) 



Trunk, 322 



Trunk fishes, 354 



Trypanosoma gambiense, 80 



Trypanosomes, 88 



Trypanosomiasis, 88 



Trypsin, 329 



Tsetse fly, 88 



Tuatara, 398, 399 



Tube-dwelUng worms, 187, 248, 249 



Tube feet, 195-200, 204-209 



Tuberculosis, 288, 516, 519 



Tubipora, 154 



Tubular nervous system, 312, 314, 473 



Tularemia, 448 



Tundra, 535-537 



Tundra region, 535 



Tunic, 316 



Tunicates, 314-320 



section of larva, 318 

 Turbellaria, 166, 167, 495 

 Turbinate bones, 335 

 Turkeys, 416 

 Turtles, 340, 388, 400, 401, 443, 481, 548 



heart, 386 



skeleton, 400 

 Tusk shells, 221, 225 

 Tusks, 448, 551 

 'Tween-brain, 334 

 Twins, 568 



Tympanic membrane, 283, 336, 337, 368 

 Tympanum, 277, 283, 336, 337 

 Tyndall, 27, 583 

 Types, 577 

 Typhoid fever. 293, 519 



U 



Ulna, 325, 327, 367, 400, 404 



Umbilical cord, 444, 446, 447 



Umbo, 212, 213 



Uncinate process, 406 



Undulating membrane, 71, 83 



Unequal cleavage, 116, 120, 218, 378, 477 



Unguiculata, 429, 434 



Ungulata, 429, 439 



Uniformitarianism, 582 



Unio complanatus, 218 



Unios, 218-220 



Uniparental reproduction, 107 



Units, hereditary, 555, 557 



Universal symmetry, 52 



Unpaired genes, 562 



Urea, 36, 329 



Ureters, 214, 217, 323, 331, 332 



Urethra, 331 



Urinary bladder, 323, 331 



Urinogenital sinus, 358 



Urochordata, 314, 316, 576 



Urodela, 370, 371 



Uroglena, 81 



Uroglenopsis americana, 80 



Uropods, 256, 257 



Urosalpinx, 229 



Use and disuse, 545, 549-550 



Uses of foods, 39, 482-483 



Uterus, 162, 163, 179, 331, 347, 377, 445 



Utriculus, 336, 337 



Vaccination, 519 



Vaccines, 519-520 



Vacuoles, 30, 64, 65, 67, 70, 71, 79, 86, 86, 129, 488 



Vagina, 162, 163 



