52 F. E. FRITSCH. 
MeMurdo Bay, September 13th, 1902 ; pond in eskers upon ice, half-way between Black 
and Brown Islands, January 3rd, 1903; pond in ice off Black Island, McMurdo 
Strait, December 31st, 1902; on ice, under boulder, Cape Adare, January 9th, 1902. 
This also is widely distributed. Some of the specimens were rather larger than 
those recorded by Messrs. West. The intermediate swellings (7.e., those between the 
central one and the subcapitate extremities) are often scarcely perceptible. 
84. NAVICULA BOREALIS. 
(PLA ties a3.) 
Navicula borealis (Bhrb.) Niitz., Bacill. (1844), p. 96, Tab. 28, figs. 68 and 72; Van Heurck, Synops. 
Diat. Belg., p. 76, Pl. VI., fig. 3. 
Long. valv. = 30p; lat. valv. = 8p. 
Jlab.—Pond some distance behind hut, Cape Adare, January 9th, 1902; fresh- 
water pond, Granite Harbour, January 20th, 1902. : 
This species was not as abundant as in the South Orkneys. 
85. NAVICULA SHACKLETONI. 
Navicula shackletoni W. and G. 8S. West, op. cit., p. 286, Pl. XXVL., figs. 136-138. 
Long. valv. = 27-40; lat. valv. = 5-6°5 p. 
TTab.—On ice, MeMurdo Bay, September 13th, 1902; pond in eskers upon ice, 
half-way between Black and Brown Islands, January 38rd, 1903; pond in ice off 
Black Island, McMurdo Strait, December 31st, 1902; freshwater pond, Granite 
Harbour, January 20th, 1902. 
This species is almost as widely distributed as V. muticopsis Van Heurck. As 
the above measurements show, some of the individuals were appreciably larger than 
those described by Messrs. West. Both the type and the var. pellucida were common. 
86. NAVICULA MURRAYI. ° 
Navicula murrayi W. and G. 8. West, op. cit., p. 285, Pl. XXVI., fig. 129. 
Long. valv. = 48 p; lat. valv. = 10 p. 
/lab.—Gap pond, Winter Harbour, rare. 
87. NAVICULA GLOBICEPS Greg. 
(PILE, figs, 1545 155.) 
Navicula globiceps Greg., Microsc. Journ., iv. (1856), p. 10, t. 1, fig. 34; Van Heurck, op. cit., p. 79, 
Suppl. Pl. A, fig. 13. 
Long. valv. = 22-38 .; lat. valv. in media parte = 9°5-12 p. 
ITab.—On ice, McMurdo Bay, September 13th, 1902; pond in eskers upon ice, 
