PLATE 3 



EXPLANATION OP FIGURES 



5 Unfertilized uterine egg, No. 58 (2), just after it entered the uterus. On 

 account of its thinness, the shell membrane has shrunken considerably. The 

 large yolk spherule is seen at one pole. The egg is slightly shrunken away from 

 the zona at one side (X 525). 



66 



