230 KIY03HI JIASÜI. 



• Schwanzmanschette " and " cliromatoider Nebenkörper " :—"VVTien tlie 

 ring-centrosome begins to move backward, the " Schwanzmanschette " gradually 

 disappears (Figs. 77, 78 \ The fate of this membrane could not be determined, 

 but it seems probable that, as Herman^n ('98) long ago described, this membrane 

 is of use for the development of the middle piece of the spermatozoa. 



The " chromatoider Nelxiukörpcr " is always placed within the " Schwanz- 

 manschette " during this period, diminishing gradually in size till it fiually 

 disappears. 



Period IV. 



The nucleus is somewhat elongated, becoming homogeneous in appearance 

 (Figs. 80, 81, 8i). Together with this, the mitochondrial gi-anules gradually 

 collect around the axial filament, and arrange themselves spirally around it, 

 the extreme end of the granules being marked by the presence of the ring- 

 shaped centrosome situated on the ix)sterior end of the cell (Figs. 80, 81, 84). 

 At the beginning of this period the anterior ceQtrosome becomes di\ided into 

 two in the direction along the surface of the nuclear wall, but still connected 

 with each other by a fine intervening fibre, and thus forming an elongated 

 dumbbell-shaped body lying close on the wall of the nucleiK. Each of the 

 two ends of this body is now seen to bo connected with the posterior 

 centrosome by a fine fibre (Figs. 80, 84). During those changes the cell bod^- 

 becomes considerably elongated while its contents, including all the fcit-grauulcs, 

 is cast ofi" as a cytoplasmic ball out of the spermatozoon, leaving only, the axi:iJ 

 filament and the mitochondrial gramiles which now as!5ume a beautiful spiral 

 slia^De (Fig. 84). 



C. The spermatid of the rabbit. 



As in the mouse the resting nuclei of the spermatids usiuilly contain 

 many chromatin granules and a large iiTogular chromatin mass which lies 

 usually at the center of the nucleus (Figs. 116, 150). Besides the latter a 

 nucleolus can be seen in the preparation st;iined with Acerbach's niethod 

 (Fig. 150). 



In the cytoplasm the idiozorce is conspicuous, wliile the clffomatoid bxly 

 can not Ixi found in most of tlie cells. But a very small body which 



