INDEX 



Tree shrew, 585 



IVcmatoda, 216, 314, 328-332; and Ccstoda, 



evolution of, 333 

 Trematodes, cuticle of, 528; int<Tnal l)uddint^ 



in, 530; polyembryony in, 530; rc[)roduc- 



tive system, 532 

 Trembley, Abraham, 294 

 Trepang, 488 



Trial-and-error behavior, 253 

 Triatoma, 463 



Tricarboxylic acid cycle, 36, 37, 114 

 Trichina worm, 353 

 Tnchinella, 353 

 Trichocvsts, 249, 250 

 Tmhodirm, 258, 291 

 Tnchonymphn , 243 

 Tricladida, 316 

 Trihvbridization, 181, 190 

 Trilobita, 422, 423 

 Trilobitomorpha, 216, 422, 423 

 Trimerotropu, 453 

 Triose, 36 



Triphosphopvridine nucleotide, 33 

 Triploid individuals, 206, 210, 211 

 Trochophore larva, 348, 356; of annelids, 



412; of gastropods, 386; of pclecypods, 



375; of polvchaetes, 401; of Pnlyaordms, 



417,418 

 Trophi, of rotifers, 345, 346 

 Trophozoites, of Entamoeba histolytica, 237, 



239; of Monocyslis, 245 

 Tropical mammals, 598 

 Trout, 559 

 Trunk, 91 



Trypanosoma aambiense, 244; T. cruzu 463 

 Trypanosomes, 243, 476 

 Trypsin, 72 

 Trypsinogen, 72 

 Tsetse fly, 244, 476 

 Tuatera, 567 

 Tube feet, of Antedon, 508; of Arhaaa, 499; of 



starfish, 493, 495; of Thyone, 503 

 Tubifex, 412, 413, 415, 416 

 Tubular glands, 60 

 Tunic, of ascidians, 545 

 Tunicata, 541 

 Tunicin, 546 

 lupaia, 385 



Turbellaria, 216, 315-327, 343, 421, 532 

 Turtle, 541, 570 



Tusks, of elephants, evolution of, 629 

 Tylosaurus, 568 

 Tympanic membrane, 90, 108; in insects, 



447, 452 

 Tyndall, and biogenesis, 260 

 Types of animals, 216, 220 225 

 Typhlosole, 406, 414, 416 



Umbilical cord, 61, 157, 163 

 Umbo, 370 



Undulating membrane, in Faramentmi, 249; in 



trypanosomes, 244 

 Unicellular animals, 10; see also I'rolo/.oa 

 Uniparental reproduction, 141 

 Urea, 79, 84 

 Ureters, 57 

 Urethra, 130 



Uric acid, 79; in locust excretion, 450 

 Urinary bladder, 50, 57 

 Urinary system, 57 

 Urine, 57,' 82, 84, 121 

 Urinogenital system, 57, 128 

 Urnatella, 356 



Urochordata, 216, 541, 545 550, 553 

 Uroclonus, 482 

 Urogenital sinus. 132 

 Uropod, in crayfish, 428; in lobster, 427 

 Uterine tube, 132 

 Uterus, 118, 124, 132, 162; of mammals, 134; 



of Ascaris, 350, 352 



Vagina, 132; of Ascaris, 350, 352 



Vagus nerve, 89 



Valves, of heart, 52; of lymphatics, 54; of 

 shell, in brachiopods, 361-362, 363, 364; 

 of shell, in pelecypods 370; of veins, 54 



Van Beneden, 142 



Varamis, 571, 572 



Variation, 172 



Vas deferens, of Clonorchis, 329; ol Taenia. 

 336; see also Ductus deferens 



Vas efiferens, of Clonorchis, 329; of Taenia, 

 336; see also Ductus elTerens 



Vascular tissue, 63-66 



Vegetal hemisphere, 146 



Vegetative cell, 39 



Veins, 51 



Veliger larva, of gastropods, 386; of pelecy- 

 pods, 375 



Venom, of poisonous snakes, 571 



Ventilation, 79, 124 



Ventral root, 98 



Ventricles, of brain, 88 



Venus, 370, 371, 375, 379 



Vermes, 224, 396 



Vertebrae, 62, 93, 533 



Vertebral column, 90, 92, 155 



Vertebrata, 216, 217, 223, 539, 541, 553-592 



Vertebrates, 10, 47; geologic succession, 625 



Vesalius, Andreas, 92 



Vestibule, Entoprocta, 356 



Vestigial limbs, of Python, 571 



Vestigial structures, 633; in human develop- 

 ment, 638 



Vicuna, 631 



Villus, 75; of chorion, 163; of intestine, 75 



Virus, 261-262; of influenza, 261 



Virus disease, of rabbits, 614 



Virus particles, 28 



Viruses, as primitive organisms, 618 



707 



