350 



INDEX 



Variation, continuous or fluctuating, 281 ; 

 discontinuous, 281-282 ; in Parame- 

 cium, 79. 



Vas deferens: Ascaris, 161; Crayfish, 

 210*; Earthworm, 167, 181*, 182, 184; 

 Honeybee, 248, 249*; Planaria, 154*, 

 156. 



Vascular system : Crayfish, 195*, 201- 

 204; Earthworm, 171, 172*; Honey- 

 bee, 241,* 242-244. 



Velum, 236*, 237. 



Ventral, 59; abdominal artery, 195*, 

 200; blood vessel, 168, 172*, 173; 

 nerve cord, 177, 205, 241*; thoracic 

 artery, 195*, 203. 



Ventricle, 241*, 242. 



Vertebrata, 5, 6, 7. 



Vestigial organs, 291. 



Virchow, Rudolph, 10, 36, 271. 



Visceral nervous system, 205. 



Vision: Crayfish, 207-208, 222; Honey- 

 bee, 246-247. 



Vitalism, 23, 24, 25. 



Vitelline membrane, 252. 



Volvocacece, 81, 92, 96, 100. 



Volvocina, 81. 



Volvox, 81, 92, 97*-99, loo, no, 228, 

 301. 



Vries, Hugo de, 274, 282, 295, 296. 



Walking: Honeybee, 238. 

 Wallace, A. R., 301. 

 Wandering cell, 147, 157*. 

 Wasp, 261, 264, 300. 



Water, carried by bees, 256; in proto 

 plasm, 21. 



Water flea, 225. 



Wax, 254^ 255 ; glands, 239, 254 ; pinch- 

 ers, 236*, 238. 



Weismann, A., 274, 287, 288. 



Whale, 10, 277. 



Whitman, C. O., 295, 296. 



Will, 304- 



Wilson, E. B., 35. 



Wing: of Honeybee, 236, 238; veins, 

 238. 



Wolff, F. K., 271-272. 



Wolves, 301. 



Worker honeybee, 234* ; cell, 255*. 



Worms, flat, 5 ; jointed, 6 ; round, 5. 



Yellow fever parasite, 80. 



Yerkes, R. M., 224. 



Yolk, glands, 154*, 156; pyramids, 215*; 



spheres, 214, 251. 

 Youth, 14, 71, 72. 

 Yucca, pollination by moth, 298. 



Zoaea, 231*, 232. 



Zoochlorella, 143, 297. 



Zoogeography, 2, 275-279. 



Zooid, 139. 



Zoology, distributional, 2 ; evolutionary, 



2; historical, 267-274; of to-day, 274; 



systematic, i. 

 Zoophyte, 139. 

 Zygote, 91, 93, 94, 95*, 96, 98, 107, 113. 



114, us- 



Printed in the United States of America. 



