FRESHWATEE ALG^. 51 



Genus Navicula Bory. 



80. Navicula muticopsiformis. 



Navicula muticopsiforme W. and G. S. West, op. cit., p. 284, PI. XXVI., fig. 131. 



Long. valv. = 12-5jLi; lat. valv. = 5-5/i. 



Hab. — Freshwater pond, Granite Harbour, January 20tli, 1902 (rather rare). 



81. Navicula seminulum. 

 (PL II., figs. 97, 98.) 



Navicula Seminulum Grun., VerhaEdl. k.k. zool.-bot. Ges., Wieii (18G0), p. 552, Tab. II., fig. 2 ; Van 

 Heurck, Synops. Diat. Belg. (1880-85), p. 107, PI. XIV., fig. 9. 



Long. valv. = 16-20 //-; lat. valv. = 4 "5-5 /a. 



Hah. — On ice, four feet above frozen watercourse through " Penknife ice," McMurdo 

 Bay, September 13th, 1902; pond in ice, off Black Island , McMurdo Strait, December 

 31st, 1902 ; in freshwater ice under boulder. Cape Adare, January 9th, 1902. 



The valves of this fairly common form were obviously swollen in the middle, and 

 very gradually tapered from there towards the two ends, which were occasionally very 

 faintly capitate. The strise were in many cases a little further apart in the middle of 

 the valve than elsewhere, in which respect the specimens approached N. minima Grun., 

 but the shape of the valve in this species is rather different. 



82. Navicula muticopsis. 



Navicula muticopsis Van Heurck, Diatomees, Result, d. voyage du S.T. 'Belgica' (1909), p. 12, PI. II., 

 fig. 181. 



Long. valv. = 13-25//.; lat. = 7-9 /x. 



Hob. — Pond, Cape Adare, January 9th, 1902 ; on ice, McMurdo Bay, September 

 13th, 1902 ; pond in ice, off Black Island, McMurdo Strait, December 31st, 1902 ; 

 Gap pond, Winter Harbour ; freshwater pond. Granite Harbour ; pond in eskers upon 

 ice, half-way betweeiT Black and Brown Islands, January 3fd, 1903 ; in ice, under 

 boulder. Cape Adare, January 9th, 1902. 



This is certainly one of the most widely distributed of Antarctic Diatoms. Both 

 of the forms recorded by Messrs. West {op. cit., pp. 283-284) were of wide occurrence. 



83. Navicula cymatopleurus. 

 (PI. IL, fig. 101.) 

 Navicula cymatopleura W. and G. S. West, op. cit, p. 285, PI. XXVI., figs. 133, 134. 

 Long. valv. = 24-30 /a ; lat. valv. = 4-5 • 5 /x. 

 Hab, — On ice, four feet above frozen watercourse, through " Penknife ice," 



