Fig. 9. Surface Views of Entire Eggs. 



A, Before entrance of spermatozoon. B, Just after en- 

 trance of sperm. C, Union of egg and sperm nuclei. D, 2-cell 

 stage. E, 4-cell stage. F, 8-cell stage. 



Fig. 10. Sections in Median Plane of Embryos. 



G, 16-32 cell stage. H, Blastula. 7, Early Gastrula. J, 

 Late gastrula. K, Early embryo. L, Late embryo. 



