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



263 



shorter or longer basal cell of the trichoblast. The antheridial 

 stand itself is a flat disc-formed body, generally with a rather 

 irregularly formed circumference. The margin is composed of large, 

 oblong, thick-walled, clear cells; inside these both the surfaces 

 are densely covered with the spermatia-forming cells, through 

 which in the middle of the antheridial stand we see a system of 

 filaments ramified subdichotomously in the same plane (Fig. 257 A). 

 These filaments Falkenberg (1. c, p. 201), who has followed the 

 development of the antheridial stands in Chondria dasyphylla, 



Fig. 258. Acanthophora spicifera (Vahl) Børgs. A, trichoblast with young 



antheridial stand. B, older antheridial stand. C, transverse section of an 



antheridial stand. D, part of the same more magnified. E, the same seen 



from above. [A, about 200:1; B, 75:1; C. 160:1; D and Æ, 400:1). 



explains as being the central cells and the cells, which bear the sper- 

 matia-forming cells as being the pericentral cells. As shown in a 

 transverse section of the antheridial stand (Fig. 258 C), cavities 

 are present between the filaments in the interior. 



The development of the antheridial stand seems entirely to 

 agree with that of Chondria as described by Falkenberg, 1. c, 

 p. 201, pi. 22, figs. 12 — 14. The ramification of the branch which 

 is destined to be the antheridial stand is made quite in accord- 

 ance with the sterile part of the trichoblast, only that its branch- 

 lets are not free, but connected together. Fig. 258/1 shows 

 a rather young stage, and fig. 258 B shows a fully developed 

 antheridial stand. In Fig. 258 D we see a transverse section of the 



