282 W. AND G. S. WEST 



Genus STAURONEIS Ehrenb. 



28 Stauroneis anceps Ehrenb. 



W. Sm. Brit. Diat. I, t. 19, f. 190 ; V. Heurck, Synops. Diat. Belg. t. 4, f. 4, 5. 

 Var. amphicephala Kiitz. 

 Long. 37-43 M ; lat. 8-10 n ; striis 22 in 10 ^ 



Hob. Recent geological deposit containing sub fossil diatoms. Also lake on west 

 side of McMurdo Sound. 



The specimens seen were rather small, but otherwise typical. 



Genus TEACHYNEIS Cleve. 



29 Trachyneis aspera (Ehrenb.) Cleve. 



Synops. Navic. Diat. I, 1894, p. 191. 



Long. 254 ^; lat. 48 ^. 



Hob. Green Lake. 



This handsome diatom was seen very sparingly, and we have not placed it definitely 

 under one of the numerous described varieties synopsised by Cleve. In outward form 

 the valves would agree with var. genuina Cleve, but in general appearance of markings 

 it agrees best with var. oblonga (Bail.) Cleve [vide figure of Stauroptera oblonga Bail, 

 in A. Schmidt's Atlas Diat. t. 48, f. 16], which is known from Australia, South America, 

 and the Island of Kerguelen. The alveolate striae were closer together (7 in 10 /) 

 near the poles of the valves than they were in the median part (6 in 10 M). 



Genus NAVICULA Bory. 



30 Navicula perlepida Grun. 



" Diatom. Franz Josefs-land," in Denk. Akad. Wiss. Wien, xlviii, 1884, p. 104, 

 t. 1, f. 44. 



Long. 16-18 n; lat. med. valv. 2.6-2.7 n. 



Hob. Clear Lake. 



This minute diatom agrees with Grunow's description of Navicula perlepida, and 

 also with his Fig. 44a. His dimensions are long. 20-34 /x ; lat. 2-3.3 M, so that the 

 Antarctic specimens, although of the same breadth, are scarcely so long as the Arctic 

 ones. 



In general form and size the valves of this diatom are very similar to species of 

 Achnanthes of the section Microneis. 



31 Navicula glaberrima sp. n. (PI. XXVI, Fig. 125) 



N. minutissima et laevissima; valvis rhomboideis vel rhomboideo-ellipticis cum 

 lateribus psene rectis, polis levissime rotundatis, raphe rectissima, nodulis terminalibus 

 conspicuis ; striis non visis. 



