278 W. AND G. S. WEST 



for a longer or shorter period in a profoundly modified condition owing to the unnatural 

 and generally abnormal conditions of the culture. 



It is very probable that several species of Glaeocystis, including G. gigas (Kiitz.) 

 Lagerh., to which the Antarctic plant nearly approaches, are independent organisms 

 with a life- history of their own. 



BACILLARIE^E 



COSCINODISCACE.E 

 Genus MBLOSIRA Ag. 



16 Melosira distans (Ehrenb.) Kiitz. 



A. Schmidt, Atlas Dial. t. 182, f. 4 ; 0. Miiller in Engler's Botan. Jahrbuch. 

 xxxiv, 1904. p. 271. 

 Diam. cell. 9,4-10 /y. 

 Hob. In pond, Cape Eoyds. 



17 Melosira varians Ag. 



W. Sm. Brit. Diat. II, p. 57, t. 51, f. 332; V. Heurck, Synops. Diat. Belg. t. 85, 

 f. 10, 11, 14, 15. 



Diam. valv. 17-19 /*. 



Hob. Ponds on Mt. Erebus. 



Genus COSCINODISCUS Ehrenb. 



18 Coscinodiscus lentiginosus Jan. 

 A. Schmidt, Atlas Diat. t. 58, f. 11. 



Diam. valv. 120 /u. 

 Hob. Green Lake, not uncommon. 



This interesting species has been found to be fairly frequent in soundings made 

 by the s.y. Belgica from 62 11' to 70 53' S. lat. 



Genus TRICERATIUM Ehrenb. 



19 Triceratium arcticum B right w. 



Diam. valv. 230-258 f i. 

 Hal). Green Lake. 



The specimens were typical, agreeing exactly with the figures in A. Schmidt's Atlas 

 Diat. t. 79, f. 12 and 12, and also with examples mounted and named by J. Tempere. 



