INDEX. 



Turkey, 413 



Turtles, 388 



Tympanic membrane, 268, 351 



Typhlosole, 224 



Ungulata, 442 



Unio, 234, 253 



Unsegmented worms, 139, 183 



Upupa, 398 



Urea, 66 



Ureter, 341, 437 



Urethra, 341, 437 



Uric acid, 66 



Urinary bladder, 341, 437 



Urodela, 379 



Uterus, 192, 342, 437 



Vagus (nerve), 347 



Variability, 94, 95 



Varieties, 102 



Vas deferens, 227, 342 



Veliger, 250 



Veins, 64 



Venomous snakes, 386 



Ventriculus (stomach), 277 



Vermes, 183 



Vermiform appendix (caecum), 434 



Vertebrae, 327, 328, 384 



Vertebral column, 325 ; divisions of, 



327 



Vertebrates, 137, 312 

 Villi, 333 

 Visceral arches, 334 



Viviparous, 342 

 Volvox, 151, 152 

 Vorticella, 150, 154 

 Vultures, 417 



Walking-stick insect, 121, 124 



Walrus, 443 



Wasps, 303 



Water-boatman, 296 



Water-vascular system, 207 



Weasel, 443 



Web (of spiders), 305 



Weevils, 302 



Whales, 441 



Whelks, 254 



White ants, 296 



Whippoorwill, 422 



Wings insects, 276 ; birds, 395 ; bats, 



446 



Wood-lice, 289 

 Wood-pecKers, 419 

 Wolves, 443 

 Worms, 139, 216 

 Wrens, 422 



Xyphosura, 303 



Yolk, 28, 29 ; influence on cleavage, 32 



Zebra, 443 



Zoea, 284 



Zoology scope, 2 ; history of, 6 



