OVARIAN OVUM OL'' CHAKTOGXATHS. 



81 



periphery many globules of various size, which may be called yolk- 

 nuclei (the black dots in the ova of fig. 1). They show similar reac- 

 tions to coloring matters as the inner part of the central body or the 

 nucleolus of the stalk-cell nucleus. Probably they are derived from 

 the latter, which persists after the fusion of the stalk-cells and changes its 

 peripheral chromatic substance to a refractive amorphous mass similar 

 to its inner part, and is metamorphosed into small globules which by 

 reunion produce larger ones. 



As to the question whether the ovum passes outside through the 

 ovisperm duct or through a temporarily formed passage as Gonant in- 

 sists, I am unable to give an opinion, as none of my specimens had ova 

 in this stage. 



In conclusion I may remark once more that in the germinal 

 epithelium of chaetognaths, there are two kinds of nuclear division, 

 mitotic and amitotic ; and that the ova are produced by mitotic, and the 

 stalk or nutritive cells by amitotic, division. This fact seems to lend 

 support to the hypothesis of Ziegler and Vom Eath on the fate of 

 the cells produced in these two different ways. 



Printed Juin 20, 1897 



