KONGL. SV. VET. AKADEMIENS HANDLINGAE. BA.ND 26. N:0 2. 59 



Var. Fenslii Grun. (1863). — Lanceolate, sometimes with subrostrate ends. L. 0,o7 to 0,12; 



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

 Longitudinal lines median. — Nav. elegans GtRUN. Verh. 1860 p. 534 PL IV f. 37. Nav. Fanzlii 

 GrEUN. Verh. 1863 p. 153. Nav. ampMsi. v. Fendii Grun. in V. H. Syn. p. 102 PL XI f. 5. 

 N. Qrunowii O'Mbara B. D. p. 362 PL XXXI f. 17. 



Brackish water: Neusiedler See, Hungary (Grun.), Rostock, fossil! Ceylon (Weissflog Coll.)! 

 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 following species, G. hivittata and C. 

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



34. C. bivittata Pant. (1889). — V. lanceolate. L. 0,o8 to 0,15; B. 0,o3i to 0,(P4 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.?) hivittata Pant. II 

 p. 43 PL V. f. 83. 



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



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

 lated margins. L. 0,i5 to 0,22; B. 0,o55 to 0,o35 mm. Axial and central areas uniting in a 

 more or less broad, irregularly lanceolate space. Striee 9 to 10 in 0,o 1 mm. slightly radiate. 

 Longitudinal lines broad or double, median. — Finniil. perm. Bail. Smiths. Cont. 1850 p. 40 PL II 

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

 PL II f. 11. Grevillb 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 over by intermediate forms to N formosa, and 

 seems also to be nearly akin to C. bivittata. 



36. C. Dusenii Cl. N. Sp. — V. rhombic-lanceolate, with subacute ends. L. 0,135; B. 0,038 

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

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

 areas. — PL IV f. 4. 



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



This species is named in honour of Mr Dus:Sn, a Swedish traveller in Western Africa, who 

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



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



37. C. madagascarensis Cl. (1890). — V. broadly lanceolate. L. 0,095; B. 0,o5 mm. 

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

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

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

 from the others). — N. madag. Ci,. 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. Fendii, from 

 which it is however quite 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 exterior 

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



38. C. Mclayata Cl. a. Grove (1891). — V. convex, gibbous in the middle and with clavate 

 ends. L. 0,i2 to 0,i6; B. 0,oi8 mm. Axial area broad, dilated around the central nodule to an 

 irregularly rounded space. Striee 10 in 0,oi mm., divergent in the ends, else almost parallel. 

 Longitudinal lines distinct, median. — Cl. a. Grove Diatomiste I p. 66 PL X f. 7. 



Marine: Macassar Straits (Grove Coll.)! 



