730 Index 



Wind, as ecological factor, 649 

 Wind scorpion, 514, 515 

 Window, oval, 222 



round, 223 

 Wing, bird, 109, 112 



insect. 112, 241, 522, 523, 530 

 Winter eggs, 441 

 Wolf, 638 

 Wolff, 278 

 Woodchuck, 77 

 Woodcock, 618, 620 

 Woodpecker, 130, 618, 619, 620, 622, 



624, 625 

 Worker, 532, 533, 534 

 Worm, 147, 159, 192, 401 

 Worm lizard, 607 

 Wormian bone. 111 

 Wren, 621, 622 

 Wrist, 109 

 Wuchereria, 436-437 



X 



X chromosome, 308. 309, 310 

 XY sex determination, 308-309 



Xiphias, 587, 589 

 Xiphoid process, 108 



Y chromosome, 308, 309, 310 

 Yellow crescent, 293 

 Yolk, 74, 280 



effect of, 282-284 



gland, 407 



sac, 285, 290 



Z chromosome, 310, 311 



Zaglossus, 629, 631 



Zoea, 508 



Zona pellucida, 262, 284, 295 



Zooecium, 483 



Zoogeographical regions, 340-341 



Zooid, 482 



Zoology, 20-22 



Zoomastigina, 353, 357-359 



Zygapophysis, 57 



Zygomatic arch. 102 



Zygote, 276, 280, 363. 364, 365, 367 



I 



