[403] THE ALG^E 167 



Docidium minutum Ralfs. 



Pleurotanium ? minutum (Ralfs.) Delponte. 

 In freshwater near Prince William Sound. 

 Diameter 1 1 //, length 135 //. 



Arthrodesmus convergens Ehrenb. (Plate XLIV, fig. 14.) 



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

 Diameter 32 /*, length 32/1 without the spines. 



Xanthidium antilopaeum (Breb.) Kuetz. (Plate XLIII, fig. 38.) 



In a freshwater pond near Cook Inlet. 



Diameter 55 ;u, length 55 ft including the spines. The spines near 

 the apex of the semi-cells are more nearly straight than in the figures 

 given of this species. 



Xanthidium armatum (Br6b.) Ralfs. (Plate XLIV, fig. 18.) 



In a freshwater pond near Virgin Bay, Prince William Sound. 

 Diameter Si //, length 128 fi. Most of the spines are bifurcated, 



with the points divergent. 



Cosmarium granatum Brb. (Plate XLIII, fig. 8.) 

 In a freshwater pond near Seldovia, Cook Inlet. 

 Diameter i8/w, length 32^1. 



Cosmarium constrictum Delp. (Plate XLIII, figs. 33, 34.) 



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

 Diameter 40 /z, length 65^. 



Cosmarium bioculatum Brb. (Plate XLIII, fig. 28.) 



Common in a freshwater pond, Seldovia, Cook Inlet (422). 

 Diameter i6-i8/x, length 1718^. 



Cosmarium hammeri Reinsch. (Plate XLIII, fig. 7.) 

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

 Diameter 10-14^, length 18-22^. Very close to the variety suban- 



gustatum of Boldt. The angles are a little more acute than in the 



type ; the apex of the semicells is very emarginate. 



Cosmarium depressum (Naeg.) Lund. (Plate XLIII, fig. 17.) 

 In a freshwater pond near Seldovia, Cook Inlet. 

 Diameter 16-20;^, length i8//. 



Cosmarium holmiense Lund. (Plate XLIV, fig. 28.) 

 In freshwater near Kukak Bay. 

 Diameter 32 /z, length 54^ 



Cosmarium venustum (Br6b.) Arch. 



In a freshwater pond near Seldovia, Cook Inlet. 



