228 



RHODOPHYCEAE 



layer, the whole being covered by a dense coating of lime, whilst in 

 C. riibens there may also be epidermal hyaline hairs. The plants are 

 monoecious or dioecious, the reproductive organs being borne in 

 terminal or lateral conceptacles. The carpogonia, which are not 



Fig. 151. Corallina officinalis. A, portion of plant. B, the same enlarged. 

 C, carpogonial conceptacle (x2io). D, single carpogonial branch ( x 342). 

 E, fusion cell, gonimoblasts and carpospores (xiao). F, development of 

 antheridia ( x 420). G, mature spermatia ( x 648). H, young tetrasporic con- 

 ceptacle ( X 240). I, mature tetraspore ( x 270). (A, B, after Oltmanns; rest after 

 Suneson.) 



calcified, arise from a kind of prismatic disk formed from the 

 terminal cells, these cells also functioning later as the auxiliary 

 cells. As a result of oblique divisions, one to three embryo carpo- 

 gonial branches are formed on each mother cell, but only one of 

 these finally develops into the mature two-celled carpogonial 

 branch with its long trichogyne. After fertilization a long or 



