1 68 



THE GERM-CELLS 



"archoplasm" of the spermatid. Suzuki's studies clearly show, how- 

 ever, that the entire axial filament of the long middle-piece arises by 

 the elongation of the inner centrosome, while the outer centrosome, 

 from which the axial filament of the tail grows out, lies at the pos- 

 terior limit of the middle-piece (Fig. 85). A nearly similar result is 

 reached by Korff ('99) in the case of Helix. It was shown by God- 

 lewski ('97) that in this form the axial filament likewise grows out 



Fig. 85. Formation of the spermatozoon in elasmobranchs. [A-C, SUZUKI ; D, Moo RE; 

 and in Helix, E-G, KORFF.] 



A-D. Outgrowth of axial filament from peripheral centrosome (<;!), which persists at the 

 posterior limit of the middle-piece or connecting-piece (m). Elongation of inner centrosome (c 2 ) 

 to form the axial filament of the latter. E-G show similar phenomena in Helix, with casting off 

 of the sphere (s) . 



a. Acrosome; c l . peripheral, and 2 . inner centrosome; / flagellum ; k. end-knob, derived 

 from inner centrosome. 



from the centrosome. Korff's later studies show that here, exactly 

 as in the elasmobranch, the axial filament grows out from the periph- 

 eral centrosome and is afterward transformed into a ring (Fig. 85). 

 The inner centrosome elongates to form a rod, which afterward 

 becomes a long filament traversing the elongated middle-piece and 

 terminating in front in an end-knob at the base of the nucleus, while 

 the ring lies at its posterior limit. The idiozome (a true attraction- 

 sphere) degenerates without taking part in the formation of an aero- 



