66 



As to the reproduction of the plant, zoospore formation takes 

 place in the cell-branches (Fig. 51). The cell contents with chro- 



matophores, nuclei 



%.,M^ 



•o O • 



cj- 



q 



o 



Fig. 50. Sipho)wcladus tropicus (Crouan) J. Ag. 



a, chromatophores with pyrenoids; h, pyrenoids; 



c, nuclei, chromatophores with pyrenoids. 



(a, about 200:1); b, 250:1; c, 300:1). 



etc. congregate to 

 thicker strings (Fig. 

 51 a). These again 

 are united in some 



irregular clumps 

 from which the zo- 

 ospores take their 

 origin (Fig. 51 b). 



The sporangium 

 consists both of the 

 original cell in the 

 mother branch and 

 the branch grown 



out from it. In the wall several holes are formed through which 



the zoospores can escape (Fig. 51 b). 



Siphonodadus tropicus has been met with in more sheltered 



places and in shallow water 



only. It is, as mentioned above, 



found growing epiphytic upon 



other algae or loose lying as Mga- 



gropila-like clumps. 



It has only been found at the 

 shores of St. Croix: in several places 

 in Lime Tree Bay and White Bay 

 on the south side and at Coakley Bay 

 on the north side of the island. 



Geogr. Distrib. West Indies, 

 Florida. 



Ernodesmis Bergs. 



Eruodesmis vcrticillata (Kiitz.) 

 Borgs. 



BoRGESEx, F., Some Chloro- 

 phycea; from the Danish West Indies, 

 II (Botanisk Tidsskrift, 32. Bd., 1912, 

 p. 259). 



Valonia verticillata Kiitz., Species 

 Algarum, p. 508; Tab. phycol., vol. VI, 

 tab. 88. J. AfJARUH, Till Algernes 

 Systematik,VIII,p. 100. P. Kuckuck, 



Fig. 51. Siphonodadus tropicus 

 (Crouan) J. Ag. 

 a and h, zoosporangia; c and d, sur- 

 roundings of the holes in the mem- 

 brane seen from the side and above, 

 rt, 5, 30:1, c, rf, 200:1. 



