[401] THE ALG^ 165 



smaller in all Its parts than the measurements given by various au- 

 thorities. 



Closterium juncidum Ralfs. 



In quiet water near Seldovia, Cook Inlet (422). 



Diameter 10 /x, length 240 /i. The plant Is slightly bent, but little 

 contracted toward the ends, which are obtusely rounded ; membranes 

 smooth, light brown ; vacuoles not apparent. 



Closterium angustatum reticulatum Wolle. 



Occasional In a freshwater pond near Cook Inlet. 



Diameter 16-19/t, length 340 ;u. The plant is dark brown, marked 

 with delicate longitudinally and spirally arranged striae. 



Closterium acerosum (Schrank) Ehrenb. (Plate xliii, fig. 27.) 

 In a freshwater pond near Seldovia, Cook Inlet. 

 Diameter 18-29^1, length 200-300 /i. 

 Virgin Bay, Prince William Sound. 

 Diameter 29 /x, length 265-300 /it. 



Closterium striolatum Ehrenb. 



In quiet water In Kukak Bay (283). 

 Diameter 25-30//, length 275-300//. 



Closterium brebissonii Delp. 



In a freshwater pond near Cook Inlet (224). 

 Diameter 18 fi, length 650//. 



Closterium lunula (Muell.) Nltzsch. 



Occasional In quiet water near Kukak Bay. 

 Diameter 70//, length 450 //. 



Closterium acutum (Lyngb.) Br6h. 



In a freshwater pool near Prince William Sound (300) . 



Diameter 8-9 //, length 85-1 00 /t. The plant is small and slightly 

 bent, ten times as long as broad, tapering from the middle to the 

 rounded ends ; cytoderm smooth and colorless. 



Closterium dianae Ehrenb. 



Freshwater pool, Prince William Sound (302) . Only one specimen 

 seen. 



Diameter 16//, length 180 /t. 



Closterium venus Kuetz. (Plate xliii, fig. 15.) 

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

 Diameter 9//, length 85//. 



Closterium parvulum Naeg. (Plate xliii, fig. 14.) 



