240 



THE ALGAE 



ments which give rise not only to the tetrasporangia, but also to 

 branched sterile filaments that grow out and form the conceptacle 

 roof by the process of division and elongation. Finally the mem- 

 brane of the tetrasporangia penetrate this roof and form exit pores. 

 The spores are arranged in a linear series. 



CORALLINACEAE : Cora//ma (coral). Fig. 134 



Both this and the preceding genus are examples of the 'fountain' 

 type of construction (cf. p. 216). In Epilithon the original con- 

 struction has been much modified because of its habit, but it can 

 be observed extremely well in Corallina. The erect plants, which 



Fig. 134 Corallina officinalis. A, portion of plant. B, the same 

 enlarged. C, carpogonial conceptacle (x2io). D, single carpo- 

 gonial branch ( x 342). E, fusion cell, gonimoblasts and carpo- 

 spores ( X 120). F, development of antheridia ( x 420). G, mature 

 spermatia ( x 648). H, young tetrasporic conceptacle ( x 240). I, 

 mature tetraspores (X270). (A, B, after Oltmanns; rest after 



Suneson.) 



