EECENT RESEA.ROHES ON SPERMATOGENESIS. 329 



lion confirmed by M. Hermann. It is needless to point out 

 the identity of this basihir nucleus and its plasma with my 

 blaslophoral cell of Helix and the Frog. 



The ampulla is now filled with polyplasts (called mother cells 

 by M. Hermann) each consisting of 30 or 40 more small cells 

 and a basilar nucleus towards its peripheral end ; and now 

 commences the process to which M. Hermann limits the term 

 Spermatogenesis, viz. the conversion of the spermatoblasts into 

 spermatozoa; but before describing this change we must lodge 

 a protest against the restriction of the term to this portion of 

 the change undergone by a cell in giving rise to spermatozoa. 

 Surely it should be applied to the whole of the changes which 

 are undergone when a germinal cell gives rise to its crop of 

 spermatozoa, as oogenesis is understood to refer to the pheno- 

 mena presented by an ovarian epithelial cell in becoming a 

 mature ovum. 



The next change that the spermatoblasts undergo is one of 

 position (fig. 1, d), something similar to what occurs in the frog, 

 only, instead of forming a vesicle, they form a sort of tube 

 filled with granular protoplasm. When this is completed, the 

 change into spermatozoa commences. 



The first event (fig. 1, f to l) is the appearance in the 

 spermatoblast of what appears to be a local consolidation of the 

 protoplasm composing the spermatoblast which M. Hermann 

 calls " corpuscle precurseur." It has but a short existence, 

 and, as far as could be made out, no connection with any 

 part of the mature spermatozoon (w). Before this has vanished 

 a small projection becomes visible at one point of the nu- 

 cleus (o), bearing, however, no relation to the position of the 

 "corpuscle precurseur." This is the (1) "nodule cepha- 

 lique," which is destined to form the head of the sperma- 

 tozoon. It seems to be a thickening of the membrane of the 

 nucleus. While the cephalic nodule is being formed, (2) a 

 rod or bar (m) appears in the substance of the spermato- 

 blast, which is in connection, by its central end, with the 

 nucleus, and by its distal end with a fine leaf-like strand of 

 plasma, which is situated at the end of the spermatoblast, 



