gog] GRIGGS— AMITOSIS IN SYNCHYTRIUM 131 



animal and plant cells (figs. 7, 18, 21, 22). No optical distinction can 

 be drawn between these extremes. The very smallest granules, how- 

 ever, do not form small nuclei but may function in metabolism. 

 In mitosis and in the degeneration of the large nuclei {'fig. 22) they are 

 cast aside with the old nuclear membrane and lost in the cytoplasm. 

 But no distinction can be drawn between these granules and those 

 which form small nuclei, for some of the latter are excessively minute. 

 Besides these, there are yet other granules on the nuclear membrane 

 from which conspicuous radiations proceed into the cytoplasm as 

 from centrosomes (fig. 39) . The discussion of these bodies involves 

 other questions than those considered* in the present paper and can- 

 not be undertaken here. Another complicating factor is the frequent 

 presence of asters near nuclei which are giving off gemmae. I have 

 avoided using such cases for the figures of the present paper, but in 

 many instances nuclei adjoining those drawn had conspicuous asters, 

 and it would be possible to duplicate most of the drawings herewith 

 given from nuclei showing asters. But though the centrosome prob- 

 km, one aspect of which was touched in a former paper (Griggs 7), 

 » very puzzling and far from solution, my belief is that it is inde- 

 pendent of the phenomena discussed in the present paper. 



HETEROSCHIZIS 



amitosis is a multiple division or fragm< 

 occurs for the most part at later stages 

 s sometimes found in voung cysts {fig 



. ~^ v wen in segmen 



^teroschizis are at once dist 

 gemmation, because thev form 



(fig. 34) . Nuclei derived by 



from 



fig. 3f) . As in nuclear gem- 



be 



formation 



: cyst. But while the new nuclei are formed one 

 - ~uk m mat process, here they originate simultaneously by the 

 coif 1 * 11 ^ 1011 ° f the mother nucleus. The first indication of division 



nuclear 



membrane 



th e f Sap ' leavin g the karyosome lying naked in the cytoplasm, like 

 some t ? m ° SOmes in the metaphase of mitosis (fig. 27). The karyo- 



en a PParently enlarges to nearlv double its former size (fig. 



