INDEX 



535 



Weevil, 409, 410 



Weismann, 232, 286, 468, 469 



Whale, 90, 128, 129, 323, 355, 419 



Wheat, 283, 310, 409 



Wheel, 443 



Wheel-animalcule, 83 



White matter, 203, 207 



White rat, 367 



Wing, 107, 355 



Wolf, 321, 336 



Woodchuck, 322 



Woodcock, 126 



Wood-lice, 90 



Woods Hole Marine Biological Lab- 

 oratory, 423 



Working hypothesis, 4, 463 



Worms, See: Earthworm, Flatworm, 

 etc. 



X chromosome, 304-311, 383 

 X-rays, 312 



Y chromosome, 304-311 



Yale University Museum, 361 



Yangtze, 418 



Yeast, 40, 41, 230, 317, 318 



Yellow fever, 391-395, 407 



Yolk, 251-255, 267, 268; plug, 268, 



269; sac, 272 

 Youth, 25 



Zona pellucida, 273 



Zoogeography, 368-373 



Zoology, 3, 4 



Zygomatic arch, 142 



Zygote, 52, 57, 59, 188, 190, 230, 231, 



238, 243, 245-247, 290-305, 340, 



468 



