(a) 



•i'Ei 



(b) 



(c) 



4>t. J 



/>"•: 



(d) 



(e) 



(f) 



(hy 



Plate II 



Fertilization of the egg of Ureckis caiipo. a, unfertilized, with intact 

 germinal vesicle and invagination; b-h, i, 2, 3, 5, 12, 30 and 35 min. 

 after fertilization. Note changes in shape and polar body extrusion. 



Tyler (1932). 



