KONGL. SV. VET. AKADEMIENS IIAN]:)]JN(1 AU. HAND 26. X:(J 2. 1?,9 



radiate; terminal stritt lo in (),(ii mm., slightly convergent; all linolv ])uii(jtate. — E11J3, Am. 1: a, 

 f. 17. M. G. XVI, I f. 11? W. .Sm. B. D. I p. .50 Pl. XVI f. 141. Donk. B. D. p. 21 Pl. III 

 f. 8. A. S. Atl. LXXII f. 1. (iiuix. Franz Josephs Land D. p. 9!) (47) Pl. I f. 34. Amphiprora 

 navicularis Ehb. Micr. G. III: 1, f. 10, 11. 



Fresli water: Fran^ Joseph.s Land (Clrun.), Svveden (Lnle Lappmark living, common in post- 

 glacial, lacu.strine deposits)! Finland, foss.! England (Hull) Donk., Germany, Harz (Atl.); Bohemia, 

 Eger fossil! North America: common in diatomaceous earths (Nova Scotia, Ganada West, Wash- 

 ington territory etc.)! 



What Nav. Semen of Ehrenberg may denote is impossible to decide, as the figures published 

 by Ehrenberg cannot be recognized. The figure in W. Smith Brit. Diat. is not good, but leaves 

 little doubt that the anthor meant the same species, which now is generally believed to be N. Semen. 

 Ou the other hand there can be no doubt that AnipMprora naviciiioides of Ehrenberg is the same 

 species as our N. ' Semen. N. Semen seems to be a northern species, rarely found living, but fre- 

 quently in postglacial deposits of Scandinavia and North America. It is not mentioned by Brun 

 as an inhabitant of the Aljjs, nor by Belloc as occurring in the Pyrenées. Its occurrence in a 

 living state in the Harz is an interesting fact and suggests that it may be a survival from the 

 post-glacial epoch. 



2. N. (Biadesmis) seiiiiiioides Cl. & Grove N. Sp. — V. elliptic-lanceolate, with truncate 

 ends. L. 0,027 to 0,045; B. 0,öi to 0,oi2 ram. Axial area narrow linear, suddenly dilated to a 

 small, orbicular central area. Strife in the middle 1(5 in 0, 01 mm., alternately longer and shorter, 

 divergent; strife at the ends about 23 in 0, 01 mm. .slightly convergent, all tinely punctate. 



Slightly brackish water: West Indies, Jamaica (Grove Coll.)! Ecuador! 



This small form resembles in oiitline N. Semen. The frustules form in living state colierent 

 filanients. 



3. N. brasiliaiiii Cl. (18<S1). — V. lanceolate, with subacute ends, ofteii slightly asymmetrical. 

 L. 0,035 to 0,065; B. 0,012 to 0,0 is mm. Median line straight; its terminal fissures in the same 

 direction. Axial area narrow, linear, somewhat dilated around the central nodule. Strife in the 

 middle 18 in 0, 01 mm, divergent alternately longer and shorter; towards the ends 21 to 22 in 

 0,01 mm.; at the ends convergent; all distinctly punctate; puucta (011 the median strise ahout 18 

 in 0,01 mm.) forming undulating, longitudinal rows. — Cynihella liradU. Cl. N. II. D. p. 4 Pl. I f. 4. 



Fresh water: Brazil! Calif. (St. Rosa in Grove Coll.)! Ecuador in mineral springs at Tesalia 

 Prov. Pichineha! 



4. N. infläta Donk. (1870). — V. lanceolate with capitate ends. L. 0,022 to 0,o26; B. 0,oo7 

 to 0,008 mm. Axial area indistinct, central area small, irregular. StriaJ in the middle 19 in 0, 01 

 mm., somewhat divergent and of unetjual length; other strite 22 to 23 in 0, 01 mm., convergent at 

 the ends, all indistinctly punctate. — Donk. B. D. p. 21 Pl. III f. 9 (nec Ktltz. = X. humjarica?) 

 Cl. D. of Finl. p. 37 Pl. II f. 2 (1891). 



Fresh water: Ireland (Lough Mourne foss. Donk.), Sweden (Lake Eosslängen in Kalmar 

 län, Rimforsa in Westergötland) ! Finland, foss.! N. America (Houghton, Michigan, foss.)! 



5. N. raniphoulos P,4nt. (1889). — V. narrow, rhombic-lanceolate, with acute ends, very 

 convex. L. O.ose to 0,09; B. O.oia mm. Median line with approximate central pores. Axial area 

 indistinct. Central area (by the distant median strite) a narrow transverse fascia. StritB about 

 14 in 0,01 mm. (the median more distant) very slightly radiate, at the ends transverse, indistinctly 

 punctate. — Pant. II p. 53 PL V f. 97, 98. 



Brackish water: Hungary, fossil! 



6. N. Criicicula W. Sm. (1853). — V. lanceolate to elliptic-lanceolate, with somewhat obtuse 

 ends. L. 0, 04 5 to 0,o7; B. 0,oi5 to O,oiu mm. Central nodule transversely dilated. Axial and 



