F. Børgesen : Rhodophyceæ of the Danish W. Indies. 



217 



where hairs seldom occur. On the other hand, in the young 

 summits of the plant being in active growth I have now by a 

 renewed examination of the plant found hairs in the ends of the 

 filaments. The hairs are about 3 fj. 

 broad and 150 // long. 



The sporangia are obovate-oblong, 

 tetrahedrally divided (Fig. 203 C, D)\ 

 they are sessile and occur on the 

 uppermost and inward side of the 



Fig. 203. Callithamnion cordatum Borgs. 

 A, base of a plant (25:1). B, end 

 of filament with hair (100:1). C, part 

 of tetrasporic plant (50:1). D, tetra- 

 spore (150:1). E, part of antheridial 

 plant (60 : 1). F, cell with antheridial 

 stand (150 : 1). G, cystocarp (60 : 1). H, 

 young procarp (150 : 1). /, older pro- 

 carp with fully developed trichogyne 

 (150:1). K, transverse section of a 

 cystocarp (60 : 1). 



Fig. 202. Callithamnion cor- 

 datum Borgs. Habit of a fe- 

 male plant. (About 60 : 1). 



mother-cell. They are found in special individuals, but a few 

 scattered tetrasporangia can also occur in the female plants (Fig. 

 204). The tetrasporangia are about 40// long and 27// broad. 



