456 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



a swollen lower portion, which contains the egg cell and 

 an upper and slightly drawn out part called the tricho- 

 gyne, which projects beyond the outer limits of the assimi- 

 lating layers into the surrounding water. The trichogyne 

 is the receptive organ for the egg cell. The spermatium 

 becomes attached to the trichogyne, but only in a very 

 few algae has the fusion of the male nucleus of the sperma- 

 tium with the female nucleus of the egg cell been 

 observed (fig. 36). 



Shortly before the supposed fertilisation the large basal 

 cell has a small cell cut off called the auxiliary cell. The 

 procarp at this point therefore consists of five cells. 



After fertilisation the trichogyne is cut off from the 

 fertilised egg cell by a complete closing up of the passage 

 between the two divisions of the carpogonium. The tri- 

 chogyne, now function] ess, soon withers away. 



The fertilised egg cell — the oospore — now grows out, 

 and forms a protuberance in a direction towards the 

 auxiliary cell. This outgrowth is a sporogenous hypha. 

 Its contents fuse with the contents of the auxiliary cell, 

 but as far as has been observed in other cases no fusion of 

 nuclei takes place. The sporogenous hypha has only been 

 fed by the auxiliary cell. From the auxiliary cell a 

 number of filaments now grow out. They are, however, 

 only continuations and branches of the sporogenous hypha 

 just mentioned, and represent sporogenous hyphse them- 

 selves. They grow towards the starch-laden collecting 

 cells. These filaments are long-celled and very thin. In 

 their course they form secondary pits with numerous 

 neighbouring collecting and conducting cells. When they 

 reach the latter they draw on their large store of food, and 

 finally give rise to the carpospores. The end cells of short 

 branches arising from the sporogenous hyphae, or their 

 last two or three cells give rise each to one carpospore. In 



