THE ALG^ 401 



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;/., length 240 .a. The plant is slightly bent, but little 

 contracted toward the ends, which are obtusely rounded ; tnembranes 

 smooth, light brown ; vacuoles not apparent. 



Closterium angustatum reticulatum Wolle. 



Occasional in a freshwater pond near Cook Inlet. 



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

 with delicate longitudinally and spirally arranged stride. 



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

 In a freshwater pond near Seldovia, Cook Inlet. 

 Diameter 18—29//-, length 200—300//., 

 Virgin Bay, Prince William Sound. 

 Diameter 29/7., length 265—300//. 



Closterium striolatum Ehrenb. 



In quiet water in Kukak Bay (283). 

 Diameter 25— 30/7., length 275— 300 /a. 



Closterium brebissonii Delp. 



In a freshwater pond near Cook Inlet (224). 

 Diameter iS/z, length 650 //. 



Closterium lunula (Muell.) Nitzsch, 



Occasional in quiet water near Kukak Bay. 

 Diameter 70 /z, length 450 //. 



Closterium acutum (Lyngb.) Br^b. 



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



Diameter 8-9//, length 85-100 /jt. 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//. 



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.) 



