﻿236 BOTANICAL GAZETTE [april 



stages in the process of general nuclear fusion, the last pairings 

 whereby the eggs become uninucleate. Trow has made much of 

 these binucleate eggs, believing the two nuclei to be sexual and 

 one of them introduced by an antheridial filament. He has been 

 bold enough to assert sexuality for four members of the group : 

 Saproleg7iia decVma, S. mixta, Achlya a>ncricana, and A. a?nencana 

 cambrica. Nevertheless, Trow presents very little evidence that 

 the so-called '*male" nucleus comes from the antheridial tube, or 

 that the latter structure ever opens into the eggs. The writer 

 cannot justify Trow's conclusions in this matter, believing them 

 premature as to evidence and illogical as to probabilities. The 

 present study will attempt to show that binucleate and trinu- 

 cleate eggs are to be expected under the peculiar conditions gov- 

 erning oogenesis. 



With respect to cytological details, investigations scattered 

 over so long a period as twelve years could hardly be expected 

 to agree. Hartog studied from entire mounts, yet was able to 

 count chromosomes and observe nuclear figures. Trow sectioned 

 in paraffin, and was at first (1895) completely deceived as to 

 the interior structure of the nucleus and the number of chromo- 

 somes. In his second paper, however, Trow (1899) concedes 

 that the nuclei in the antheridia and oogonia divide mitotically, 

 but his figures are far from clear as to detail. Trow was also 

 mistaken in his interpretation of the nucleolus. 



The present study will give a more detailed account of 

 nuclear structure and activities than any previous paper. But 

 the most important contribution relates to certain cytoplasmic 

 manifestations that seem to determine in large part the results 

 of oogenesis. These cytoplasmic activities place the process of 

 oogenesis in Saprolegnia in a new light, bringing it into sympa- 

 thy with conditions in Albugo, Peronospora, and Sclerospora. 



They are concerned with that cytoplasmic structure termed the 



coenocentrum. 



It is not strange that Humphrey, Hartog, and Trow failed 

 to find the coenocentrum, for its recognition demands exception- 

 ally good fixation and staining. It is probable that Dangeard 

 saw it when he described an oil globule or fatty mass in the cen- 



