THE ALG^ 407 



Staurastrum furcigerum Breb. 



In a freshwater pond near Seklovia, Cook Inlet (422). 

 Diameter 45 //., length 50 //. 



Staurastrum arctiscon (Ehrenb.) Lund. 



In a freshwater pool, Virgin Bay, Prince William Sound (302). 

 Common. 



Diameter 1 16 ij.. 



Staurastrum polymorphum Br^b. (Plate xliii, figs. 23, 24.) 

 In a freshwater pond near Seldovia, Cook Inlet (402). 

 Diameter 40 //, length 4^^ /z. The end view shows four arms 



rounded at the ends. 



Staurastrum echinatum (Perty) Rab. (Plate xliii, fig. 16.) 

 In a freshwater pond near Seldovia, Cook Inlet. 



Euastrum verrucosum Ehrenb. (Plate xliii, fig. 9.) 

 In freshwater, Popof Island. 

 Diameter 81 //, length 88 fi. 



Euastrum gemmatum Breb. 



In a freshwater pond near Seldovia, Cook Inlet. 



Diameter 40 //, length 67 //. The plant agrees exactly with Br^b- 

 isson's description except that the terminal lobe is not emarginate. 



Euastrum pokornyanum Grun. 



In a freshwater pond near Kukak Bay. 



Diameter 21 /a, length 43 [j.. The basal lobe of the trilobe semicell is 

 crenate, the terminal lobe subcuneate, truncate and excised; membrane 

 smooth. 



Euastrum oblongum (Grev.) Ralfs. (Plate xliii, fig. 37.) 



In a freshwater pond near Prince William Sound. 



Diameter 67 /^, length 130 /x. The semicells are five lobed, all of 

 the lobes having the broad shallow marginal cavity. 



Euastrum crassum (Breb.) Kuetz. (Plate xliii, fig. 4.) 

 In a freshwater pond near Seldovia, Cook Inlet. 

 Diameter 68 //, length 148 //. 



Euastrum didelta (Turp.) Ralfs. (Plate xliv. Fig. 24.) 



In freshwater near Kukak Bay. 



Diameter 46-60 ,a, length 86-120 //, sinus 16 // deep, bridge 1 1 /x 

 wide. 



Euastrum ansatum Ralfs. 



In a freshwater pond near Yakutat Bay. 

 Proc. Wash. Acad. Sci., November, 1901. 



