330 



ly protruding four corners the sides of the net are evenly concavely 

 rounded with no processes or edges in their middle (Fig. 330 a). 

 The edges protrude into rather long, at the farthest end nearly cylin- 

 drical, elongations with a large, circular opening; the borders of these 

 are adorned by small acute processes (Fig. 330 a). The very protru- 

 ding corners make the edges of the plant highly sinuate (Fig. 331 b). 





Fig. 330. Dictyurus occidentalis J. Ag. 



a, transverse section of the thallus (comp. text). 



I), part of the plurisiphonous main axes. 



(a, about 10:1, b, 100:1). 



Fig. 331 a shows a part of a poorly developed shoot. In this 

 the growing-together of the summit of the filament in one branch- 

 system with the filaments of another one above is clearly demonstra- 

 ted. 



The cells in the net are about 60 70 ju thick and 1% times 

 as long. 



All the material gathered was sterile. 



I have been able to compare my specimens with the original 

 material of this species, collected atVeraCruzbyLiEBMAN and being 

 preserved in the Botanical Museum, Copenhagen. The original spe- 

 cimens belong to a very small and tiny form reaching a heighth of 

 about 5 cm only. As mentioned above the axes of the sympodia, 

 bearing the net, are, in the specimens I have examined, monosiphonous. 



