62 P. T. CLEVE, SYNOPSIS OK THE NAVICULOID DIATOMS. 



Var. afrkana Cl. — V. elliptic-linear, with broad and roiinded end.s. L. 0,i3; B. 0,25 mm. 

 Longitudinal lines crossiiig the stritt; in their middle. Stria; 15 in O.di ram. — Pl. IV f. 5. 

 Bi-ackish water: Cameroon! 

 The var. africana merits perhaps to be considered as a distinct species. 



50. C. Holstii Cl. (1881). — V. elliptical, with parallel margins and cuneate end.s. L. 0,o5 2 

 to 0,06; B. 0,016 to 0,0-2 mm. Axial area very narrow; central area small, rounded. Striie 14 in 

 0,01 mm. almost paraDel, not distinctly or finely punctate. Longitudinal lines marginal. — A. S. 

 Atl. L. f. 48 (without name). Kav. Holstii Cl. D. f. Grönl. and Argentina p. 11 Pl. XVI f. 1. 



Fresh water: Greenland! Albany, Maine, fossil! Oregon (Atl.). 



51. C. Liulogeusis Cl. (1891). -- V. broad, lanceolate. with subrostrate ends. L. 0,o2.t; 

 B. 0,0 14 mm. Axial area indistinct; central area small rounded, somewhat transverse. StriK- 17 

 in 0,01 mm. slightly radiate, finely punctate. Longitudinal lines marginal, faint. — Xav. Ladoy. 

 Cl. D. of Finl. p. 35 Pl. II f. 3. 



Fresh water: Ladoga, on the surface of the lake! 



-^ö"' 



52. C.'{ (lispersa Gii. and Sturt (1887). — V. almost flat, elliptic-lanceolate, with subacute 

 ends. L. 0,o8; B. 0,0 2 7 mm. Median line straight, terminating close to the margin. Axial area 

 narrow, dilated in the middle to a small rounded space. Stria; 27 in 0,oi mm., finely punctate, 

 puncta forraing undulating longitudinal lines. The strife are coufined to an irregnlar, lanceolate 

 space aronnd the axial area, the part outside of this space being irregularly and coarsely punctate. 

 Longitudinal lines inframarginal. — Nav. disp. Gr. and Sturt. Queck. M. Cl. III (2) p. 132 

 Pl. X f. 10. 



Marine: Oamaru, N. Zeeland, fossil! 



This is remarkable species, which I have placed here only with hesitation. The longi- 

 tudinal] line is visible only in strongly oblique light. A somewhat- similar form oceurs at 

 Monterey, which I know by a sketch sent by Grunow, who calls it Mastogloia? decorata. This 

 form is smaller (L. 0,o33; B. 0,oi3 mm.) and has a larger quadrate central area and probably 

 coarser stria3. 



53. C? sejuucta A. S. (1874). — V. linear, with parallel margins and rounded cuneate 

 ends. L. 0,o4; B. 0,oi mm. Axial and central areas indistinct. Strife 12 in 0,oi mm. transverse. 

 Longitudinal lines broad, submarginal. — Nar. scjitncta A. S. N. S. D. p. 87 Pl. I f. 18. 



Marine: North Sea, Campeachy Bay (A. S.). 



I have not seen this species, which A. Sciimidt seems to consider akin to Diploneis 

 nitescens. It seems to me more probable that it belongs to the group of C. FoircUii. Xo indica- 

 tion of the nature of the stria; exists. If punctate this form raay be a Diploneis; if smooth it 

 belongs to the gronp of O. Poivellii. 



54. C. blanda A. S. (1874). — V. linear, with rounded ends. L. O.dr, to 0,i:i; B. (».m to 

 0,0 18 mm. Axial area narrow. Central area orbicular, large. Stritc 8 to 10 inO.oi mm. parallel, 

 radiate at the ends, not distinctly punctate. Longitudinal lines ln'oad. — Nar. blanda A. S. X. 

 S. D. p. 90 Pl. II f. 27. Finn. crgadensis Greg. T. M. S. is.^i; p. 48 Pl. V f. ii? 



Marine: Xorth Sea! Black Sea! Ceylon! Seychelles! Amboina! Labnan! Taiiitil 



55. C. Siipergradata Bri-n. (1.S91). — V. convex, linear, witli munded ends. L. O. ur. to 

 0,135; B. 0,0 16 mm. Axial and central areas combined in a broad, linear space. Median line 

 strongly tlexuose. Stria' (i in 0, 01 mm., parallel smooth. Longitudinal lines broad, marginal. — 

 Nav. supergr. Brun. D. Esp. n. p. 40 Pl. XV f. 6. 



Marine: Gulf of Naples! Port d'Alger (Brun), Bosphorus (Brun). 



