50 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



„, f Axial area broad O. supergradata Beun 



' \ — — narrow or indistinct ... . 66. 



f Central area orbicular . . ... ... 67. 



66. •{ — — quadrate .... .... 68. 



I — — indistinct . . .... . .... 70. 



( Valve narrow ... . C. blanda A. S. 



\ — broad, almost hexagonal . . ■ C. quadriseriata Ol. a. Geun. 



I Longitudinal lines marginal . . . . . . C. Campbellii Pet. 



\ — — median . . ,. ... . . . 69. 



i Longitudinal lines rather narrow C Powellii Lewis. 



\ — — — broad C. arnica Ol. a. Gkun. 



I Strise about 31 in 0,01 mm. . C. venusta Pant. 



I — 5 to 10 — . 71. 



Stri» 5 in 0,0 1 mm. . C. Zanardiniana Geun. 



71. ^ - 8 — C. Wittii Geun. 



— 12 — ... . C. sejuncta A. S. 



67. 

 68. 

 69. 

 70. 



1. C, lepidula G-eun. (1880). — V. narrow, linear, with broad, rounded ends. L. 0,02; 

 B. 0,006 mm. Axial area indistinct; central small, orbicular. Striae parallel, 27 to 30 in 0,oi mm. 

 Longitudinal lines marginal. — Nav. Up. Gkun. in V. H. Syn. p. 108 PL XIV f. 42. 



Fresh water: Belgium (V. H.). 



2. C. bacillaris Gkeg. (1856). — V. linear, with rounded ends. L. 0,023 to 0,05; B. 0,oo5 

 to 0,006 mm. Axial area very narrow; central area small, sometimes unilaterally dilated to a fascia. 

 Strise 20 to 22 in 0,oi mm. almost parallel. — Nav. bacillaris Greg. M. J. IV PL I f. 24. V. H. 

 Syn. PL XII f. 27. 



Fresh water: Scotland (Greg.), Illinois (G-rove Coll.)! 



3. €. fasciata Lagstr. (1873). — V. linear to linear-lanceolate, with broad rounded ends. 

 L. 0,023 to 0,037; B. 0,005 to 0,008 mm. Axial area indistinct or narrow. Central area a broad 

 fascia. Longitudinal lines indistinct, striee parallel 24 to 26 in 0,oi mm. — Nav. fasciata Lagst. 

 Spitsb. D. p. 34 PI. II f. 11. V. H. Syn. PL XII f. 34. Nav. fonticola Grun. V. H. Syn. 

 PL XII f. 32 (1880). Nav. fontinalis Grun. V. H. Syn. p. 103 PL XII f. 33. Nav. Bacillum var. 

 inconstantissima Grun. in V. H. Syn. PL XII f. 28. Nav. Lacunarum Grun. V. H. Syn. PL XII 

 f. 31. Stauroneis Bacillum Geun. Verb. 1863 p. 155 PL IV f. 16. Nav. {molaris var.?) ahyssinica 

 Grun. in Martelli Flornla Bogosensis p. 152 PL I f . 4 (1886). 



Fresh or slightly brackish water: Spitsb.! Iceland! Scotland! Sweden! Finland! Belgium! 

 Abyssinia (Grun.). N. Zealand! N. America, Hoboken, N. Jers! Dakota! Brazil! Ecuador! Argentina! 



This little form has some resemblance to some small Pinnularise of the section ParallelistriatEe, 

 so that Grunow (V. H. Syn. PL XII f. 34 text) considers the form from Spitsbergen to be a Pinnu- 

 laria. I think it is more akin to Nav. Bacillum. The longitudinal lines are not distinct in most 

 specimens, but I have seen such lines faintly on specimens from slightly brackish water at Pitea 

 (Gulf of Bothnia), which I am unable to distinguish from the larger form, named by Grunow Nav. 

 Lacunarum. As I can see no difference between Nav. fasciata and Grunows Nav. fonticola, Nav. 

 fontinalis and Nav. Lacunarum I have united them. 



A probably allied form is Nav. Greguti Herib. a. Perag. (D. d'Auvergne p. 119 PL IV f. 17 

 and var. lanceolata f. 18) fossil in the Auvergne Deposits. The valve is more lanceolate, in L. 0,028 

 to 0,035 mm. The strise are stated to be 12 to 15 in 0,oi mm. Stauroneis aCM^wscw^a of the same 

 author (p. 78 PI. Ill f. 20) with 20 strise in 0,oi mm. also fossil from Auvergne may be a 

 form of Coloneis fasciata, or possibly of Stauroneis (Pleurostauron) parvula Grun., which I am 

 unable to decide without original specimens. 



4. C. Beccariana Grun. (1886). — V. gibbous in the middle, with broad capitate ends. L. 

 0,026 to 0,074; B. 0,007 mm. Axial area narrow, central area a broad, transverse fascia. Strise 



