888 Index 



Water-lungs, 217 Worms. See also Annelids. 



Waves, sound, 471 Wren, temperature regulation in, 364, 365 



Weberian ossicles, 486 W-substance in amphibian color changes, 



Weight, oxygen consumption and, 226 705 



Whale, blood and urine concentrations in, 



62 Xanthine oxidase, distribution of, 203 



Wood, digestion of by insects, 172 Xanthophores, 681 

 Woodchuck, hibernation in, 371, 372 control of in fish, 711 



Worms, parasitic, osmoregulation in, 17 Xenopus, color changes in, 704 



polychaete, ventilation in, 262 Xylan, digestion of, 173 



respiratory pigments in, 294 



uricolytic enzymes in, 203 Yarbow, respiration in, 256, 257 



ft 



