604 



Figures 36 to 43 are selected from a section of the vas epidi- 

 dymis lined with the tallest type of columnar epithelium. The "brush 

 border" is here distinct and well preserved. The nuclei at all stages 

 appear vesicular. Figures 41, 36 and 37 illustrate early phases and 

 show how the division begins by a pushing in of the nuclear mem- 

 brane. In fig. 42 constrictions appear at opposite poles and progress 

 centralward. Figures 39, 38 and 40 represent progressively later 

 stages in the direct division consummated in different planes. Figure 

 43 again represents the spiral type of division. This type in its 

 various degrees is perhaps the most common. The rotation is more 

 complete than can well be illustrated. Change of focus shows that 



32 33 34 35 



@ © i # 



^J 37 38 39 40 41 42 43 



Figs. 32 to 35. Selected cells from still another section. Cells 32, 34 and 

 35 are in early phases of amitosis; 33 is at a late phase. 



Figs. 36 to 48. Selected cells from a single section of the vas epididymis lined with 

 the tallest type of ciliated columnar cells. Progressively later phases of amitosis 

 are illustated in the series 86, 41, (42), 87, 39, 38, 40, (43). All the types and 

 phases illustrated for the tubules with cuboidal types of cells are almost equally 

 abundantly present in the tubules with columnar cells. The prevailing type of divi- 

 sion is unquestionably amitotic; not a single mitotic figui-e appears in my preparations. 



the two daughter nuclei actually fit over each other along the con- 

 cave faces. 



In certain more favorable regions both in the vasa efferentia 

 (figs. 16 to 24) and the vas epididymis (fig. 40) terminal bars and basal 

 granules are distinctly visible. In less favorable regions the distal 

 margin of the cells appears marked by a slightly darker staining 

 narrow band. This same band resolves into granules in certain 

 especially well preserved cells, to which granules the cilia are appa- 

 rently attached. 



