50 F. E. FRITSCH. 



DIATOMACE^. 

 Genus Diatom a D.C. 



77. DiATOMA ELONaATUM. 



Var. EHRENBERGI. 



(PL III, figs. 152, 152a.) 



Diatoma elongatum Ag., Syst. Alg. (1824), p. 24 ; Kiitz., Bacill. (1844), p. 48, t. 17, fig. xviii., 1, 2. 

 Var. ehrenbergii (Kiitz.) W. Sm., Brit. Diat. ii. (1856), pp. 40-41, PI. XLL, fig. 311 /8 (D. ehrenlergii 

 Kiitz., Bacill. (1844), t. 17, fig. xvii., 1-3). 



Long. valv. = 26-32 fx.. 



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

 McMurdo Bay, September 13th, 1902. 



This variety has already been recorded from the Antarctic by Van Heurck [o]). cit.). 

 The ends of the frustules often appeared somewhat rounded in girdle-view (fig. 152). 



ACHNANTHACBiE. 



Genus Achnanthes Bory. 



78. Achnanthes brevipes. 



Var. intermedia. • 



Achnanthes hrevipes Ag., Syst. Alg. (1824), p. 1. 



Var. intermedia (Kiitz.) Cleve, Synops. Navic. Diat., ii. (1895), p. 193 {A. suhsessilis Kiitz.). 



Long. valv. = 30-31 "5 /a; lat. valv. = 9-9' 5 ju,. 



Hab. — On Phormidium on ice, four feet above frozen watercourse through 

 "Penknife ice," McMurdo Bay, September 13th, 1902 (rare). 



The specimens agreed in all respects with those described and figured by Messrs. 

 West {op. cit., p. 280, PI. XXVL, figs. 126-127). 



NAVICULACEiE. 



Genus Stauroneis Ehrenb. 



79. Stauroneis anceps. 



Var. AMPHICEPHALA. 



Stauroneis anceps Ehrenb., Verbr. u. Einfl. d. mikr. Lebens, etc. (1843), p. 134, Tab. II., 1, fig. 18 • 



Smith, Brit. Diat., i. (1853), p. 60, Tab. XIX., fig. 190. 

 Var. amphicephala Kiitz., Bacill. (1844), p. 105, Tab. 30, fig. 25. 



Long. valv. = 28 /A ; lat. valv. = 8 /a. 



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



