THE RELATION BETWEEN AMITOSIS AND MITOSIS. 2OI 



are sometimes found which have apparently become entirely 

 separated from the cytophore. 



The spermatid nuclei contain at this time only a few very dis- 

 tinct deeply staining granules (some of the nuclei in Fig. 44, PI. 

 XIV.) : in cases where extraction is carried to extremes only two 

 granules, one at the peripheral end of the nucleus, the other 

 near the middle or at one side of the nucleus (some of the 

 nuclei in Fig. 44, PI. XIV.). The peripheral granule is closely 

 applied to the nuclear membrane, so closely indeed that it is 

 often difficult to determine whether it is inside or outside the 

 nucleus. In some cases, however, it is clearly inside the nucleus 

 (Fig. 44, PI. XIV.) and this is probably its position in all cases. 



The first visible step in the formation of the spermatozoon is 

 the appearance at the periphery of the cytoplasm peripheral to 

 the nucleus of a minute deeply staining granule. In position 

 this granule corresponds to the peripheral centrosome which 

 enters the middle piece in the spermatozoa of many other forms. 

 It has been impossible in consequence of the small size of these 

 cells to obtain any data regarding its origin in this case. If the 

 spermatids arising by fragmentation do produce spermatozoa the 

 question as to its origin in those cases is of some interest. This 

 peripheral body which apparently lies in contact with the border 

 of the cytoplasm appears to be connected by a very delicate 

 cytoplasmic strand or fiber with the granule at the peripheral end 

 of the nucleus (Figs. 44 and 45, PI. XIV.). Whether there is 

 another cytoplasmic granule in contact with or near the nucleus 

 corresponding in position to the other centrosome of other forms 

 could not be determined. From the peripheral granule in the 

 nucleus the delicate fiber appears to continue through the nucleus 

 usually to the second granule (some of the nuclei in Fig. 44, 

 also Fig. 45, PI. XIV.). This continuation of the fiber within 

 the nucleus has been a matter of the most careful examination 

 and I can say regarding it only that I have seen it in the nuclei 

 of practically every cytophore examined and under the most 

 various conditions of fixation and staining so that if present 

 methods of technique permit trustworthy conclusions in regard to 

 such matters its existence seems beyond doubt. The figures ex- 

 aggerate its distinctness to some extent. It does not stain as 



