57 



tetraspores having already ms.tured before the involvicro,! 

 rays are formed. The rp.ys are expanded curved plates, con- 

 nected £i,t the hcise v/it]i the vegetative cell, and free lat- 

 erally and terminally. Usually nei^^hboring rays are in 

 contact at the sides, so tliat the circle of tetrasjiores is 

 well screened from without. Each ray is a single cell sim- 

 ilc-T in appeccrance a,nd in structiu'e to the outer cell of 

 the involucral ray of the cyptocarp, Y/here the rays sjre 

 in connection witli the vegetative cell, the pliigs character' 

 i^tic of the intercelliilar connections elsev/here a.re form- 

 ed. 



The tetraspores £ire formed a,s follows: Around the up- 

 per border of a young cell below the apex, protoplasm ac- 

 cuiTiUlates in sma.ll rounded ma.sses, each containing a single 

 nucleus (fig. 106) . The cell wall near each protoplasmic 

 accumulc-tion becomes gelatinous, which a,llows the acciunula- 

 tions to protrude as small papille.e (fig, 107), Each of 

 these papillae early becomes cut off from tlie mother cell 

 by a delicate dome-shaped membrane (fig, 108), Each of 

 the cells so formed, witli its nucleus, increases in size, 

 and at tlie same time t]ie membrane loses its convex form and 

 becomes flattened (fig. 109). 



The fori!ia.tion of these prima.ry tetrasporic cells seems 



