[407] THE 



Staurastrum furcigerum Bre"b. 



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

 Diameter 45 ;*, length 50 p. 



Staurastrum arctiscon (Ehrenb.) Lund. 



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

 Common. 



Diameter 116 /x. 



Staurastrum polymorphum Brb. (Plate XLIII, figs. 23, 24.) 

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

 Diameter 40 /A, length 45 /*. 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 /*. 



Euastrum gemmatum Breb. 



In a freshwater pond near Seldovia, Cook Inlet. 



Diameter 40 //, length 67 /*. The plant agrees exactly with Breb- 

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



Euastrum pokornyanum Grun. 



In a freshwater pond near Kukak Bay. 



Diameter 21 p, length 43 p. 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 /A, length 130 /*. 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 p. 



Euastrum didelta (Turp.) Ralfs. (Plate XLIV, Fig. 24.) 



In freshwater near Kukak Bay. 



Diameter 46-60 p., length 86-120 //, sinus 16 p. deep, bridge n p. 

 wide. 



Euastrum ansatum Ralfs. 



In a freshwater pond near Yakutat Bay. 



