KONGL. SV. VET, AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 41 



puncta forming undulating longitudinal rows, about 8 in 0,oi mm. — Coccon. gl. Cl. D. Arct. Sea 

 p. 14 PL III f. 12. N. sp. A. S. Atl. VI f. 39. N. gl. Grun. Fr. Jos. Land D. p. 55. Petit 

 Cape Horn D. p. 123 PI. X f. 16, 17 (1888). Icon. n. PI. I f. 28. N. herguelensis Castr. Chal- 

 lenger Voy. D. PI. XXVIII f. 16 (according to Petit). 



Marine: Greenland! Spitsbergen! MatotscMn Scharr! Cape Horn (Petit), Kerguelens Land 

 (Castr.). 



Var. septentrionalis Cl. — V. smaller. L. 0,o4 to 0,05; B. 0,o35 mm. Puncta in the median 

 part of the valve scattered or forming short, undulating rows. — A. S. Atl. VI f. 37. 



Marine: Arctic America! Greenland! Spitsbergen! Sea of Kara! Cape Horn (Petit). 



The original figure in D. of the Arct. Sea shews a marginal rim, which I have since found 

 to be occasioned by the zone. There is no rim on detached valves. The var. septentrionalis connects 

 the type with N. algida. 



6. N. Xi Cl. N. Sp. — V. elliptic-lanceolate, with rostrate ends. L. 0,055 to 0,o-f,\ B. 0,022 

 to 0,032 mm. Axial area narrow; central large, orbicular. Striae 12 to 13 in 0,oi mm. radiate 

 throughout. Puncta 12 in 0,oi mm. Among the median striae are some few shorter ones. 



Marine (Mouth of rivers): Sierra Leone (Deby Coll.)! Cameroon! 



7. N. Delta Cl. (1893). — V. elliptical, with rostrate ends. L. 0,032; B. 0,oi6 mm. Axial 

 area narrow; central orbicular. Striae 12 in 0,oi mm., radiate throughout, coarsely punctate; 

 puncta 12 in 0,oi mm., equidistant. Among the median striae there are some few shorter ones. — 

 Diatomiste II p. 14 PL I f. 10. 



Marine: Ceylon (Weissflog Coll.)! 



8. N. pusilla W. Sm. (1853). — V. elliptical to lanceolate, with more or less distinctly 

 rostrate ends. L. 0,03 to 0,047; B. 0,oi5 to 0,025 mm. Axial area narrow; central area small, 

 orbicular. Terminal fissures in the same direction. Striae 13 to 18inO,oi mm. radiate throughout, 

 in the middle of unequal length; puncta distinct, 16 to 20 in 0,oi mm. — B. D. I p. 52 PL XVII 

 f. 145. V. H. Syn. p. 99 PL XI f. 17. N. tumida var. genuina Grun. Verb. 1860 p. 537 PL IV 

 f. 43 a; v. suhsalsa Grun. f. i. c. — N. pus. var. spitsbergensis Grun. A. D. p. 40 (Cl. M. D. N:o 158). 



Fresh or slightly brackish water: Spitsbergen (Grun), England! Arctic America! Mouth of 

 Jenissey! Bahamas! Surinam! Tasmania! Cameroon! 



Var. lanceolata Grun. (1860). — Lanceolate, with slightly or scarcely rostrate ends. L. 0,04; 

 B. 0,015 mm. Striae 11 in 6,01 mm. — A. D. p. 40 PL II f. 47. N. gastroides Greg. M. J. Ill 

 p. 40 PL IV f. 17 (1854). N. pulchra Greg. T. M. S. IV p. 42 PL V f . 7 (1856). N. tumida v. 

 lanceolata Grun. Verb. 1860 p. 537 PL IV f. 44. N. turn. v. suhsalsa Strose Klieken f. 10. 



Brackish water: Germany, Berlin (Grun.), Klieken, foss. (Strose), Sweden, Lysekil! Hungary, 

 Neusiedlersee (Grun.), Mouth of Jenissey! 



Var. jamalinensis Grun. (1880). — V. lanceolate with broad rostrate ends. L. 0,04; B. 0,oi6 

 mm. Central nodule incrassate around the median pores. Striae 13 in 0,oi mm. — A. D. p. 40 

 PL II f. 48. 



Brackish water: Sea of Kara (Grun). 



9. N. Demerarae Grun. (1893). — V. broadly lanceolate, with acute or obtuse ends. L. 0,o46 

 to 0,085; B. 0,017 to 0,03 mm. Axial area narrow or indistinct. Central area large, irregular, 

 with one, or a few, larger puncta near the central nodule. Terminal fissures in contrary direction. 

 Striae 15 to 17 in 0,oi mm. somewhat closer near the ends, radiate, punctate; puncta 19 in 0,oi mm. 

 Median striae of unequal length, terminal striae parallel. — Diatomiste 11 p. 14 PL I f. 9. 



Fresh water: Demerara River! Surinam (Kinker Coll.)! 



,10. N. delawarensis Grun. (1893). — V. elliptic-lanceolate, with subrostrate ends. L. 0,o85 

 to 0,1; B. 0,044 mm. Median line with distant central pores. Axial area narrow. Central area 



K. Vet. Akad. Haadl. Band 37. N:o 3. 6 



