82 PROTISTS AND DISEASE 



In the agamic stages S. endobioticum contains a good 

 deal of chromidial material derived from the nucleus, but 

 no definite chromidial zone enveloping the nucleus such as 

 Stevens found in 8. decipiens is produced. The passage of 

 chromatin into the nucleus by a series of discharges rather 

 than in a continuous stream as appears to have been 

 observed in other species is perhaps a variable phenomenon : 

 the difference is that in one case there is a series of unipolar 

 mitoses, in the other a stream of chromidial elements. 

 Possibly equable experimental conditions determined the 

 regularity of the various stages in 8. endobioticum. 



The Gametic Stages of S. endobioticum. The complete 

 examination of this one species that we owe to Dr. Curtis 

 calls for comparison with what has been found in other 

 species and for reflection upon the facts. 



There is little doubt that the formation of zygotes by 

 conjugation of zoospores will prove to be general in 

 Synchytrium. 



In Pycnochytria (in de Bary's sense) only the gametic 

 part of the life-cycle will probably be found, and it will be 

 interesting in this group, and in that division of the Eusyn- 

 chytria which produce a sorus from the resting-cell (S. 

 stellariae &c.) to see what exactly are the nuclear and 

 chromidial processes in the gametic sorus. Cells infected 

 by zygotes divide leaving the parasite in the deeper daughter 

 cell, Fig. 22, e. This division is repeated till the infected 

 cell lies under two or more layers of uninfected cells. 



