212 C. M. CHILD. 



formed gradually make their way to the periphery of the cyto- 

 phore and probably give rise to spermatozoa, though this cannot 

 be demonstrated with absolute certainty. 



Apparently only a part of the nucleus is involved in the for- 

 mation of -the anterior end of the spermatozoon in which no 

 " head " is visible. The sperm- head is apparently represented by 

 two granules in the nucleus, one peripheral, one more or less 

 nearly central and a less deeply staining fiber which connects 

 them, these being in most cases the only deeply staining portions 

 of the nucleus. When development of the spermatozoon is 

 completed the nuclear portion is apparently set free from the 

 remainder of the nucleus by the degeneration of the latter. 



Groups of cells in all stages of development except the spireme 

 stage are frequently attacked by degenerative processes probably 

 because of insufficient nutrition or exhaustion. 



HULL ZOOLOGICAL LABORATORY, 

 UNIVERSITY OF CHICAGO, 

 September, 1906. 



