50 F. E. FRITSCH. 



DIATOMACE^E. 







Genus DIATOMA D.C. 



77. DIATOMA ELONGATUM. 



Var. EHRENBERGI. 



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



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

 Var. ehrenbergii (Kiitz.) W. Sm., Brit. Diat. ii. (185G), pp. 40-41, PI. XLI., fig. 311 ft (D. ehrenlergii 

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



Long. valv. = 26-32 p.. 



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 (op. tit.). 

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



ACHNANTHACE.E. 



Genus ACHNANTHES Bory. 



78. ACHNANTHES B.REVIPES. 



Var. INTERMEDIA. 



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



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



Long. valv. = 30-31 '5 /A; lat. valv. = 9-9 '5 p.. 



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. tit., p. 230, PI. XXVI., figs. 126-127). 



NAVICULACEvE. 



Genus STAURONEIS Ehrenb. 



79. STAURONEIS ANCEPS. 



Var. AMPHICEPHALA. 



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



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

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



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



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



