66 p. T. CLKVE, SYNOPSIS OF THE NAVIODLOID DIATOMS. 



Var. versicolor Grun. (1874). — Lateral areas broader, not constricted in the middle. Stritu 

 10 in 0,0 1 mm. punctate, puncta 17 to 20 in 0,oi mm. — N. versicolor Gkun. A. S. N. S. D. II 

 f. 17. Atl. LXX f. 18 to 22. V. H. Syn. PI. X f. 6. N. rovignensis GtRUN. in Cl. M. D. N:o 209 

 (1879). N. seductilis var. Perag. Villefr. D. p. 49 PL II f. 20. 



Marine: North Sea! Mediterranean Sea! Adriatic! Sumatra! 



Var. nummularia Grbv. (1859). — V. nearly orbicular. L. 0,023 to 0,04.5; B. 0,oi7 to 0,o3 8 

 ram. Striae 10 in 0,oi mm. finely punctate, puncta about 18 in 0,oi mm. — N. numm. Grev. 

 Edinb. N. Ph. J. X p. 29 PL IV f. G. iV: forcip. var. nummularoides Grun. A. S. Atl. LXX f. 30, 

 31, 39, 40 (1881). 



Marine: Adriatic (Atl.), Bab el Mandeb! Madagascar! Cape of Good Hope (Atl.), Java! 

 California guano (Grev.), Florida! 



Var. suh orbicularis Grun. (1880). — As var. nummvilaria, but with closer striae, 13 to 14 

 in 0,01 mm. L. 0,oi8 to 0,036; B. 0,oi2 to 0,024 mm. — V. H. Syn. PL X f. 5. 



Marine: Spitsbergen! North Sea! Balearic Islands! Seychelles! Zulu Sea (Deby Coll.)! Gala- 

 pagos Islands! 



Var. densestriata A. S. (1881). — Eliptical. L. 0,o3 to 0,o6; B. 0,oi2 to 0,oi8 mm. Striae 

 15 to 22 in 0,oi mm. — Atl. LXX f. 12 to 16. N. fore. var. minor A. S. Atl. LXX f. 32. A. S. 

 N. S. D. I f. 44. 



Marine: North Sea! Corsica! Cape of Good Hope! Java! Japan! Campeachy Bank (Atl.). 



This variety connects N. foreipatu and N. pygmcea, so that the latter might be regarded as 

 a variety of N. forcipata. 



Var. balnearis Grun. (1880). — V. linear-elliptical. L. 0,03 7; B. 0,oi mm. Lateral areas 

 not constricted in the middle, and forming by their junction a broad stauros. Striae 18 in 0,oi 

 mm. — ]Sf. pygm. var. balnearis Grun. in V. H. Syn. X f. 8. 



Slightly brackish water: Sweden, Ronneby, fossil! 



Additional. 



N. seriosa Pant. (Ill PL XXXII f. 464). — Elliptical, rostrate-acuminate. L. 0,047; B. 0,033 

 mm. Lateral areas moderately broad, with scattered linear markings, very slightly constricted in 

 the middle and convergent at the ends. Striae 12 in 0,oi mm. distinctly punctate. 



Marine: Hungary, fossil (Pant.). 



Naviculse Lsevistriatse Cl. 



Valve in outline more or less lanceolate. Axial area linear, abruptly dilated around the 

 central nodule to an orbicular space, or transverse fascia, or uniting with the central area in a 

 more or less broad, lanceolate space. Striae usually coarse, radiate, not distinctly punctate or 

 lineate, not crossed by longitudinal lines or furrows. Terminal fissures of the median line usually 

 small and indistinct. Connecting zone not complex. 



This section is remarkable for its apparently smooth striae, and might on that account have 

 been placed in the genus Pinnularia. But most of the species bear a closer relationship to the 

 true Naviculae than to the Pinnulariae, and, besides, it is possible that the striae may be only 

 apparently smooth. Nav. palpebralis, which I place in the section, is usually described and figured 

 as having distinctly punctate striae, but I have never been able to detect any punctate character 

 in its striae. It does however contain several forms (as for instance Nav. bituminosa) which are 

 closely related to species of Pinnularia, belonging to the section divergentes of that genus. On 

 the other hand several species shew a close affinity to those of the section Entoleice of Navicula. 



