PLATE 5 



EXPLANATION OF FIGURES 



15 A tube egg, showing the second polar body at the left and the sperm head 

 at the right. 



16 A series of drawings showing the changes in the sperm head: a, a sperma- 

 tozoon in the tube. The head was drawn from a stained section — the tail was 

 added from data of a living spermatozoon, b to g, various stages in the transfor- 

 mation of the sperm head within the egg. 



314 



