KONaL. sv. VKT. AKADEMIENS HANDLINGAR. BAND 26. N:() 2. 59 



Var. Fcnzlii Grön. (1863). — Lanceolate, sometimes witli subrostrate eiuls. L. O, o 7 to 0,12; 



B. 0,028 to 0,042 mm. Area narrow, dilated around the nodule. Striai 11 to 14 in 0, 01 mm. 

 Loiigitudiiial lines median. — Nav. elegans Grun. Verh. 1860 p. 534 Pl. IV f. 37. Nuv. Fendii 

 Grun. Verh. 1863 p. 153. Nav. amphish. v. Femlii Grun. in V. H. Syn. p. 102 Pl. XI f. 5. 

 N. Grimotvii 0'Meara B. D. p. 362 Pl. XXXI f. 17. 



Brackish water: Neusiedler See, Hnngary (Grnn.), Rostock, fossil! Ceylon (Weissflog fJoU.)! 

 Calcutta (Deby Coll)! Batavia! Jamaica! St Martin, W. Ind.! Guatemala, fossil! St. Monica, fossil 

 (Dr. Rae Coll.)! 



All these forms are closely connected, so that it seems to me impossible to regard them 

 as distinct species. They are also nearly akin to the two foUowing species, C. hicittata and U. 

 permagna, of which the latter is, by intermediate forms, connected with C. formosa. 



34. C. bivittata Pant. (1889). — V. lanceolate. L. 0,o8 to O,!,-, ; B. 0,o3i to 0,o4 mm. 

 Axial and central area uniting in a broad, lanceolate space. Strife 10 (middle) to 12 or 13 (ends) 

 in 0,01 mm., slightly radiate. Longitudinal lines double. — N. {oregonica var.?) bivittata Pant. II 

 p. 43 Pl. V. f. 83. 



Brackish and marine: Hungary, fossil! Atlantic City, N. Jers. foss. (Deby Coll.)! 



35. C. permagua Bail (1850). — V. rhombic-lanceolate, sometimes with slightly trinndu- 

 lated margins. L. 0, 15 to 0,22; B. 0,0.55 to 0, 035 mm. Axial and central areas uniting in a 

 more or less broad, irregnlarly lanceolate space. Strite 9 to 10 in O, o 1 mm. slightly radiate. 

 Longitudinal lines broad or double, median. — Finnul. 2}erm Bail. Smiths. Cont. 1850 p. 40 Pl. II 

 f. 28, 38. Nav. permagnu Ralfs Pritch. Inf. p. 907. Lewis Proc. Ac. n. se. Philad. 1861 p. 70 

 Pl. II f. 11. Greville t. M. S. XIV p. 127 Pl. XII f. 18 to 21, 1866. V. H. Syn. p. 102 Pl. XI f. 1. 



Brackish water: Anvers (V. H.). N. America (New-York to Florida and Gulf of Mexico)! 

 This large and beautiful species passes över by intermediate forms to N. formosa., and 

 seems also to be nearly akin to C. bivittata. 



36. C. Diisenii Cl. N. Sp. — V. rhombic-lanceolate, with subacute ends. L. 0, 13 r»; B. O, o. "5 8 

 mm. Axial area narrow. Central area moderately large, orbicular, without any markings. Strise 

 13 in 0,01 mm., radiate, in the ends slightly convergeut. Longitudinal lines approximate to the 

 areas. — Pl. IV f. 4. 



Brackish water (mouths of rivers): Cameroon, Africa! 



This species is named in Iionour of Mr Dusen, a swedish traveller in Western Africa, who 

 procured me an interesting gathering from that country. This beautiful form greatly resembles 



C. permagna, but difPers by the closener of its longitudinal lines to the areas. 



37. C. iiiadagascarensis Cl. (1890). — V. broadly lanceolate. L. 0,095; B. 0,on mm. 

 Median liiie with distant central pores. Axial and central areas uniting in a narrow, lanceolate 

 space. Median line bordered by thick silicious ribs. Striee 9 in 0, 01 mm. radiate troughout, in- 

 distinctly punctate. Longitudinal lines three, of which the median is the strongest (and differs 

 from the others). — N. maclag. Cl,. Diatomiste I p. 23 Pl. IV f. 2. 



Marine: Madagascar! Columbo, Ceylon (Letourneur Coll.)! Java! 



This is a remarkable species, having some resemblance to C. amphisbcena var. Fenzlii, from 

 which it is however qnite distinct. Of the three longitudinal lines the median has the appearence 

 of a narrow furrow, separating the flatter axial part of the valve from the sloping exteriör 

 part. The other lines are formed by small knöts on the strise. 



38. C, l)iclavata CJl. a. Grove (1891). — V. convex, gibbous in the middle and with clavate 

 ends. L. 0,12 to O, le; B. 0,oi8 mm. Axial area broad, dilated around the central nodule to an 

 irregularly rounded space. Strite 10 in 0, 01 mm., divergent in the ends, else almost parallel. 

 Longitudinal lines distinct, median. — Cl. a. Grove Diatomiste I p. &G Pl. X f. 7. 



Marine: Macassar Straits (Grove Coll.)! 



