982 



INDEX 



Vitelline membrane, 903 



as osmotic membrane during early chick 

 and frog development, 241 



in egg of amphibia, 167 



in egg of elasmobranch fishes, 165 



of egg of Scy Ilium canicula, 163 



of frog's egg, 166 



of hen's egg, 167 

 Vitelline veins, 727, 737, 743 



primitive, 736 



transformation of in chick, 742 

 Vitellocytes, 326 

 Vitreous body, of eye, 846 

 Viviparity, 903 

 Viviparous species, 902 

 Vogt, W., 344, 355 

 Voice box, of bird, 648 

 von Baer, Karl Ernst (1792-1876), 71, 

 213, 521 



laws of, 521, 522 

 von Dungern, E., 223 



W 



Wachowski, H. E., 878, 879, 886 



Wagner, 213 



Waldeyer, W., 114 



Wang, H., 119 



Water, elimination of, 771 



Weber, M., 6 



Weismann, A., 114, 334 



Wells, L. J., 6, 12, 46 



Whale, characteristics of egg, site of ferti- 

 lization, and place of sperm en- 

 trance into egg, 206t 



Wharton, Thomas, 877 



Wharton's jelly, 663 



White commissure, ventral, 821 



White matter, 810, 819 



Whitman, C. O., 473 



Williams, L. W., 570 



Williams, R. G., 41, 43 



Willier, B. H., 120, 592, 593, 892 



Willis, T., 876 



Wilson, E. B., 286, 287 



Wilson. H. v., 324, 437, 458, 559 



Wilson, J. M., 308, 473 



Wilson, W. L., 286 



Wiltberger, P. B., 927 



Wimsatt, W. A., 197 



Winslow, foramen of, 873 



Wirsung, duct of, of pancreas, 629 



Wirsung, J. G., 629 



Wislocki, G. B., 6, 23, 27. 892, 923 



"Witch's" milk, in newborn human male 



and female, 588 

 Witschi, E., 791, 794, 795. 891, 892 

 Wolffian (mesonephric) duct, 777, 799 



origin of in Squalus, 775 

 Woodchuck, hibernating gland of. 665 

 Woollard, H. H., 764 

 Wright, E. S., 305, 904 



X 



Xenopus laevis, xviii 



use of in pregnancy test, 927 

 X-rays, effect on germinal epithelium, 120 



Yellow crescent, appearance of at fertili- 

 zation in egg of Styela, 246. 286 

 Yochem, D. E.. 196 

 Yolk, localization of at egg pole, 160 

 "Yolk-attraction sphere," 157 

 Yolk bodies, 157 

 Yolk body, in egg of fowl. 755 

 Yolk nucleus, 157 

 Yolk sac. 902 



blood islands of. 733 



external, in shark embryo. 925 



fate of. 925 



internal, in shark embryo, 925 



types of. 908 

 Yolk-sac placenta, 917 

 Yolk spherules, origin of, 157 

 Yolk stalk, 911 

 Yolk synctium, in elasmobranch fishes, 



322 

 Young, care of, 899, 929 



number produced and care. 900 

 Young, W. C, 36 



Zona pellucida, 162. 168. 901, 903 

 of reptile oocyte, 167 



Zona radiata. 162. 903 

 in amphibia. 167 

 of Chrysemys picta, 166 

 of egg of fowl, 766, 167 

 of egg of teleost fishes, 165 

 of elasmobranch fishes, 165 

 of reptile oocyte, 167 



Zonary placenta, 914 



Zondek, B.. 40. 926 



Zonula ciliaris, 853 



Zygonema meiotic threads. 135 



Zygote. 113. 211 



Zygotene stage of meiosis. 132, 135 



