1914] 



GETM AN— OOGENESIS IN HORMOSIRA 



269 



be present in the egg. Since there 

 has been no reduction division, 

 the three mitoses characteristic of 

 oogenesis in Fucus have been sup- 

 pressed in Sargassum. However, 

 out of the large number of con- 

 ceptacles examined in this form, 

 one oogonium was found which 

 contained two eggs and two 

 oogonia that contained eight; this 

 was regarded as a rare reversion 

 to the Fucus type. The above 

 instances in oogenesis form a series 



1 



-b 



Fig. 6. — Conceptacle: a, Bower's 



beginning With the eight eggs of -initial"; 6, -basal" cell; X480. 



Fucus and ending with the par- 



thenogenetically developed egg of Sargassum. Oogenesis in Fucus 



is regarded as the primi- 



tive typ 



the others 



lie. 7. — Conceptacle: first formed para- 

 physes; X410. 



as reductions from it. 



Oltmanns, Kutzing, 



and Gruber have all men- 

 tioned the ultimate forma- 

 tion of four eggs in 

 Hormosira, but no investi- 

 gation has been made of 

 the conditions of oogenesis. 

 The material was fixed 

 in Flemming's weaker 

 solution with the osmic 

 acid a little weaker than 

 the formula requires. As 

 in Oltmanns' account of 

 Ascophyllum, simultaneous 

 free nuclear division 

 takes place, resulting in 



2-nucleate, 4-nucleate, and 



8-nucleate stages (figs. 



