18 P. T. CLEVE, ON DIATOMS FKOM THE ARCTIC SEA. 



Förh. 1868, pag. 226). Finmarken Grötsund very rare. Strit 

 coarse 17 — 18 in 0,025 m.m. Length 0,07, Breadth 0,03. 



75. Navicula marina Ralfs (in Pritcli. Inf. pag. 902 

 Donh. Br. D. pag. 19, Pl. III, fig. 5. Nav. jjunctulata S] 

 Syn. I, pag. 52, pl. XVI, fig. 151). Bavis Strait in mu' 

 from deep water, only one specimen observed; Strise 23 i; 

 0,02 5 m.m. Length 0,0544, Breadth 0,03i m.m. 



76. Navicula subsalina Donk, (Br. Diat. pag. 24, Pl. I^V 

 fig. 2). Spetsbergen Hackluyts. 



77. Libellus Grevillei (Ag) Cl {Schizonema Grevillei S 

 Syn. II, pag. 77, Pl. LVIII, fig. 364. Navicula Libellus Gre> 

 Diat. of Clyde pag. 528, Pl. XIV, fig. 101. Navicula Grevill 

 Cl. Öfvers. af K. Vet. Akad. Förh. 1868, pag. 665). Fii 

 marken Grötsund. Spetsbergen Schoal Point, Amsterdam I 

 (20 fths). Danes Id. (6 fths) Kings Bay (160 fths). 



I have separated the new g aus Libellus on acconnt 

 the structure of the connecting inembrac?, which has seve?- 

 lougitudinal ribs or »plica?» (prot"bly rud^ of diaphragm 



I am not able to find any im^ brtant d .»^nce between Scii. 

 zonema Grevillei and Nav. I ellus, ^^ i- which reason I ha 

 placed them in one species 



Navicula Grevellei D nk. 1871 (Brit. DJ^t. pag. 47) i 

 quite another species ner .ly related to X. crabro. 



78. Stauroneis aspera Ehb (St. jyulchella Sm Syn I, pag 

 61, Pl. XIX, fig. 194). Certainly the most common of al 

 diatoms in the arctic sea and scarcely absent from an^ 

 sample of mud. Fimnarken. Greenland. Spetsbergen. Abound' 

 in all seas. 



? 79. Scoliopleura convexa (Sm) Grun. ^v. convexa Sm 



Syn. I, pag. 49, Pl. XVI, fig. 136). SpetsbVrg--. Kings Ba^ 

 rare. Stri» unusually coarse 15 in 0,02 5. (Acf^^ Aiing to Smitl 

 21 in 0,0 1"). 



80. Rhoicosigma arcticum Cl. X. Sp. S. V. elongate, sig- 

 moid, acuminate; nodule central; med. line irregularly bent: 

 striae delicate, transverse, about 37 — 44 in 0,025 m.m. but still 

 visible in balsam. F. V. linear, bent, narrow. 



