﻿1903] OOGENESIS IN SAPROLEGNIA 245 



expected, for in general the three nuclei share between them the 



metabolic possibilities of about the same amount of protoplasm 



as is in the uninucleate ^^^^ The trinucleate ^^g probably 



I develops, as does the binucleate, from an ^%^ origin in which 



more than one nucleus by fortunate position is able to survive 

 the processes of general degeneration. 



Let us now examine Trow's position respecting sexuality in 

 the Saprolegniales. It is presented most completely in his 1899 

 paper. I approach this subject with some diffidence, for it has 

 already been the occasion of detailed discussions of a personal 

 character (Hartog, 1896, 1899). The matter is finally reduci- 

 ble to a question of confidence in Trow's evidence, his account, 

 and his figures. Everyone must admit the possibility of sexual- 

 ity in the Saprolegniales, but the question for us is, does Trow 

 prove it? 



The binucleate ^gg gave Trow the conviction, as he acknowl- 

 edges, that fertilization took place through the introduction of 

 a male nucleus into the ^gg from an antheridial tube. But the 

 present studies show that binucleate eggs are quite common in 

 an undoubted apogamous form, the material being entirely free 

 from antheridial filaments. Moreover, these binucleate eggs 

 have been followed through younger stages back almost to the 

 period of the ^gg origins, and we know that these two nuclei 

 were sisters in the oogonium. To make this point more plain, ■ 

 let the reader contrast the appearance of the two small nuclei 

 shown in figs, 22 and 2j with the nuclei in older eggs [figs. 19- 

 -?/), and it will be evident that the former have the size and struc- 

 ture of nuclei in the young oogonium, and not of the fully mature 

 gamete {^gg) nucleus. It should also be noted that Hartog's 

 binucleate eggs were also from apogamous material (Hartog, 

 1898 and 1899, p. 450). 



If. then, apogamous material may have binucleate eggs, and 

 the events of oogenesis explain the conditions, we are justified 

 in examining Trow's evidence of sexuality very critically and 

 demanding of it exceptional fulness and accuracy. We are con- 

 cerned chiefly with Trow's figures, for they should show most 

 exactly what the investigator really saw. I have been impressed 



