51 



The rays do not form a definite pericarjj, as tliey are not 

 united at tlxe sides. ITone are produced "between tlie cysto- 

 carp and the vegetc;,tive cell .'hich bears it. 



The placental cell formed at tlie division of the aujc- 

 iliary cell increases in size and in nuiaher of nuclei, all 

 of v/hich are the product of tlie division of the fusion nu- 

 cleus. Small protuber8,nces are formed on its free border, 

 each of v/hich conta,ins a, single nucleiis (figs. 91,92). 

 Each protuberance is cut off from the mother cell by an 

 arched membrane, and the cells so formed give rise by re- 

 peated division to the sporogenous cells from v/hich tlie 

 carpospores are formed. 



While this is taking place, there is a general fusion 

 of cells in tlie center oi" the cystocarp (figs. 91,93,94). 

 The follov/ing cells take part in this fusion; the placental 

 cell, the auxiliai^y cell, the central cell, and sometimes 

 the peripheral cells. The result of the fusion is the pro-- 

 duction of a very It^rge, iri-egulairly sharped placenta., on 

 the upper sur-face of v/hich the sporogenous lobes cire form- 

 ed (figs. 94,95) . 



The placenta contains nuclei from tliree sources: (1) 

 the original nuclei of the peripheral and au:<:iliary cells, 

 v/hich appeitr to take no part in spore foi^mation, (2) the 



