50 p. T, CLEVE, SYNOPSIS OP T[IE NAVICULOID DIATOMS. 



„. f Axial area broad C. supergradata Beun 



' \ — — narrow or indistinct 66. 



{Central area orbicular 67. 

 — — quadrate 68. 

 — — indistinct 70. 



^^ j Valve narrow C. hlanda A. S. 



I — broad, almost hexagonal C. quadriseriata Cl. a. Grun. 



„ I Longitudinal lines marginal C Campbellii Pet. 



\ — — median 69. 



,.f, ( Longitudinal lines rather narrow C. Poivellii Lewis. 



— — — broad C. arnica Cl. a. Grun. 



Stria3 about 21 ip (),oi mm C. venusta Pant. 



— 5 to 10 — -.71. 



Striae f) in 0,oi mm C. Zanardiniana Grun. 



8 — C. Wittii Grun. 



12 — C. sejunda A. S. 



I 

 -I 



[ Stris i 



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

 B. 0,oor. mm. Axial area indistinct; central small, orbicular. Striae parallel, 27 to HO in 0,iii mm. 

 Longitudinal lines marginal. — Nar. Up. Grun. in V. H. Syn. p. 108 PI. XIV f. 42. 



Fresh water: Belgium (V. H.). 



2. C. Mcillaris Greg. (1856). — V. linear, \yith rounded ends. L. 0,023 to 0,o.^); B. 0,o()r> 

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

 Striiu 20 to 22 in 0,oi mm. almost parallel. — Nav. hacillaris Greu. M. J. IV PI. I f. 24. V. H. 

 Syn. PI. XII f. 27. 



Fresh water: Scotland (Greg.), Illinois (Grove Coll.)! 



3. C. fiisciat.a 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, strise parallel 24 to 26 in 0,oi mm. — Nav. fasciata Lagst. 

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

 PL XII f. 32 (1880). Nav. fontinaUs 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 Grun. Verb. 1863 p. 155 PL IV f. 1(5. Nav. {molaris var.?) ahyssinica 

 Grun. in Martelli Florula 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 Pinnularice of the section Parallelistriatse, 

 s(i that Grunow (V. H. Syn. PL XII f. 34 text) considei\s the form from Spitsbergen to be a Pinnu- 

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

 s[)e('imens, but I have seen such lines faintly on specimens from slightly brackish water at Pitea 

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

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

 foitfinulis and N((r. Lacuiuo'um I have imited them. 



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

 and var. hnircnlafa f. 18) fossil in the Auvergne Deposits. The valve is more lanceolate, in L. 0,02 8 

 to 0.03;-) mm. The .strite are stated to be 12 to 15 in 0,oi mm. Sfauronei.<> acufiuscula of the f^ame 

 antluii- (p. 78 PL III f. 20) with 20 stria', in 0,oi mm. also fos.sil from Auvergne may be a 

 I'diiii of ('olontis fasciata, or possibly of Stauro)ivis (Flcnrostauron) parrnla Grun., which I am 

 unal)le to decide without original specimens. 



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

 0,020 to 0,074; B. 0,007 mm. Axial area narrow, central area a broad, transverse fascia. Striae 



