260 S. SAGUCHI 



duced by amitosis, for mitosis of ciliated cells has never been 

 observed here. Next, cytoplasmic division follows, the plane of 

 which is always vertical. Sometimes the amitotic process seems 

 to occur repeatedly; in figure 63 is a ciliated cell with six nuclei 

 which are closely apposed on their flat side-faces; I am of opin- 

 ion that the nucleus, in this case, has repeatedly undergone 

 amitotic division, while cytoplasmic fission has not begun. 



5. Efferent tubules of Reptilia. Ciliated cells with two nuclei 

 often occur in the efferent tubules of Trigonocephalus and Ela- 

 phis (figs. 72-74), but rarely in the lizard. The direction of 

 constriction of the nuclear membrane is not a constant ; the plane 

 of cytoplasmic division, however, is always perpendicular. 



6. The oviduct of the lizard. Binucleated ciliated cells are 

 rarely seen here (fig. 77) ; the two nuclei which are evident must 

 have been produced by amitosis, for mitosis has not been de- 

 tected. 



7. The trachea of Trigonocephalus. The two nuclei, either 

 superposed or juxtaposed, are closely apposed by their flat faces; 

 between these extremes there occur intermediate conditions. 



8. The trachea of the rat. The arrangement of the two nuclei 

 is the same as described under 7 (fig. 93). The cell-body grad- 

 ually enlarges, especially increases in width. The cleavage of 

 the cytoplasm begins either at the upper or at the lower end of 

 the cell (fig. 94), and passes perpendiculraly between the nuclei. 

 I have also often noticed that a granule accompanies each of the 

 divided nuclei; from their position, shape and staining it is prob- 

 able that these granules are derived from the pre-existing centro- 

 some. 



Sumrnary 



1. The ciliated cell may divide by amitosis. 



2. This cell multiplication by amitosis occurs only in verte- 

 brates. 



3. The nucleus and the cell-body are constricted by pushing 

 in of the nuclear membrane. 



4. Cell-division follows nuclear division. 



5. The ciliary apparatus remains unaltered in the amitotic 

 process. 



