280 W. AND G. S. WEST 



23 Fragilaria virescens Ralfs 



V. Heurck, I.e. t. 44, f. 1. 

 Long. valv. 40 n; lat. 8.5 M . 

 Hob. Ponds on Mt. Erebus. 



24 Fragilaria obliquecostata V. Heurck 



Diatomees, Result. Voyage du s.y. " Belgica" Anvers, 1909, p. 25, t. 3, f. 38. 

 Long. valv. 47 /u ; lat. 8 n ; costis 6 in 10 ju. 

 Hob. Green Lake, frequent. 

 Forma maxima V. Heurck, I.e. f. 40. 

 Long. valv. 75 M; lat. med. 8.5 /x> costis 5j in 10 M. 

 Hob. Green Lake, rare. 



The valves were not so large as those described and figured by Van Heurck, but 

 they possessed the same slightly tumid median portion. 



ACHNANTHACE.E 



Genus ACHNANTHES Bory. 



25 Achnanthes brevipes Ag. var. intermedia (Kiitz.) Cleve 



Synops. Navic. Diat. II., 1895, p. 193 ; A. subsessilis Kiitz., 1833. 



Long. valv. 31-33 /* ; lat. 8.8-9.3 . (PL XXVI, Figs. 126, 127) 



Hob. Moraines near camp, Cape Royds. Clear Lake. 



In outward form the valves were similar in form to those of A. brevipes var. inter- 

 media, although not quite so elliptic, and occasionally there was a faint indication 

 of a median constriction. The markings agreed well with the general disposition of 

 the punctate costse of this most variable species. We figure the upper and lower 

 valves for future comparison with other Antarctic forms. 



Striations on lower valve 13 in 10 n, strongly radiate; on upper valve 12 in 10 M, 

 transverse in the middle of the valve, but rather irregularly bent towards the poles. 



COCCONEIDACE^E 

 Genus COCCONEIS Ehrenb. 



26 Cocconeis litigiosa V. Heurck 



Diatomees, Result. Voyage du s.y. "Belgica," Anvers, 1909, p. 18, t. 2, f. 28. 

 Long. valv. 79 /m ; lat. 54 n ; striis 9 in 10 p. 

 Hob. Green Lake, rare. 



Only the inferior valves were seen, and although a little smaller than Van Heurck' s 

 original specimen, they possessed precisely the same striation. Moreover, they 



