52 F. E. FKITSCH. 



McMurdo 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 [i.e., those between the 

 central one and the subcapitate extremities) are often scarcely perceptible. 



84. Navicula borealis. 

 (PI. Ill, fig. 153.) 



Navicula borealis (Ehrb.) Kiitz., Bacill. (1844), p. 96, Tab. 28, figs. G8 and. 72 ; Van Heurck, Synops. 

 Diat. Belg., p. 76, PI. VI., fig. 3. 



Long. valv. = 30 /a ; lat. valv. = 8 ju,. 



Ilab. — 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. Navicdla shackletoni. 

 Navicula shacMeloni W. and G. S. West, op. cit., p. 286, PI. XXVI., figs. 136-138. 



Long, valv, = 27-40 /a ; lat. valv. = 5-6 • 5 /a. 



Ilah. — On ice, McMurdo 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; freshwater pond, Granite 

 Harbour, January 20th, 1902. 



This species is almost as widely distributed as N. 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 mdrrayi. 



Navicula murrayi W. and G. S. West, op. cit., p. 285, PL XXVI., fig. 129. , 



Long. valv. = 43 /a; lat. valv. = lO/t. 

 //a?;.— Gap pond. Winter Harbour, rare. 



87, Navicula globiceps Greg. 

 (PI. Ill, figs. 154, 155.) 



Navicula gloiiceps Greg., Microsc. Journ., iv. (1856), p. 10, t. 1, fig. 34; Van Heurck, op. cit, p 79 

 Suppl. PI. A, fig. 13, ' 



Long. valv. = 22-38 jx ; lat. valv. in media parte = 9 • 5-12 /a. 



Eab.— On ice, McMurdo Bay, September 13th, 1902; pond in eskers upon ice. 



