638 



INDEX 



VORTICELLA : occurrence and 

 general characters, 269 ; struc- 

 ture, 269 ; reproduction, 273 ; 

 conjugation, 274 ; means of 

 dispersal, 274 ; encystation, 

 275 ; spore-formation, 276 ; 

 metamorphosis, 276 ; prac- 

 tical directions, 277 



Vulva, 487, 540 



W 



Waste-products, 8, 66. 249 

 White matter of brain and 



spinal cord, 156, 160, 167 

 Wolffian body, see Epididymis 



duct, 603 



Work and waste, 66, 148, 234 

 Worms, 349 

 Wrist, see Carpus 



X 



Xiphisternum, 48, 500 



Y 



Yellow cells of Earthworm, 331, 



335, 34i 

 Yolk, yolk-granules or spheres, 



I 95> 564, 569 ; and see under 



various types 

 Yolk-cells, 200, 202 

 Yolk-plug, 20 1, 581 

 Yolk-sac, 470, 582, 586 



Zona radiata, 586 



Zoochlorella, 304 



Zooid, 277, 309 ; and see Mega- 



zooid and Microzooid 

 Zoology, i 



Zoophytes, see Hydroid polypes 

 Zygapbphysis, 36, 498 

 Zygoma, zygomatic arch, 494, 



495 

 Zygote, 197, 251, 275, 284 



PRINTED IN GREAT BRITAIN* nv RICHARD CI,AY & SONS, LIMITED, 



lit'NGAV, SCFFOI.li. 



