FUNCTIONAL AND RUDIMENTARY SPERMATOZOA. 329 



loosely arranged and persists in this form throughout the remain- 

 der of the development of the cell. From one end of the cell 

 a process extends which is somewhat flexible in its earlier de- 

 velopment. Fig. 2, B, shows such an early stage in which the 

 tail-like process has become curved and wrinkled after treatment 

 with Zenker's fluid. Later this tail-like process becomes very 

 rigid and stiff. So stiff that when the immature males are crushed 

 this process by chance may be driven through the nuclear 

 material to the opposite side of the cell as shown in Fig. 2, C, or 

 in some instances it was even driven through the opposite wall 

 of the cell as shown in Fig. 2, D. Normally this stiff process 

 seems to be attached to one end of the cell. Later, however, 

 when it is fully formed it becomes detached from the cell. This 

 separation of the two parts of the cell occurs in the testis either 

 before the male hatches from the egg or very soon thereafter. 

 Fig. 2, C, shows the two parts just prior to separation. 



This stiff spindle-shaped part contains no chrornatin material 

 and probably is to be considered the rudimentary tail of the cell. 

 It is immotile and much smaller than the tail of the motile sper- 

 matozoon. As it separates from the nucleated portion of the 

 cell and is immotile one could naturally conclude that it is to be 

 regarded as simply a degenerate or rudimentary tail which has 

 no function. Whether the nucleated portion of the cell has any 

 function is unknown but as it is also immotile it is also very 

 probably functionless. 



In the earlier studies the detached tails of the normal sper- 

 matozoa were erroneously considered to be the entire spermatozoa. 

 When the males were crushed under ar cover glass these tails were 

 extruded and were able to move about in the water for a consid- 

 erable length of time. When recently, however, these so-called 

 spermatozoa were stained no nucleus or chrornatin material 

 could be found in any of them. As they are the functional sper- 

 matozoa it was realized that there must be a nucleus and chro- 

 rnatin material somewhere in them. 



It was recalled that in previous observations some males had 

 been seen to extrude a few of these motile bodies which had a 

 large swelling on the anterior end. At that time these motile 

 bodies were considered to be the immature spermatozoa. When 



