66 P. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



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

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

 f. 17. Atl. LXX f. 18 to 22. V. H. Syn. Pl. X f. 6. N. rovignensis Grun. 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. nummiilaria Grev. (1859). — V. nearly orbicular. L. 0, 023 to 0,045; B. 0, 017 to O, oas 

 ram. Strise 10 in 0, 01 mm. finely punctate, puncta about 18 in 0, 01 mm. — -A^. nmmn. Grev. 

 Edinb. N. Pb. J. X p. 29 Pl. IV f. 6. -A' forcip. var. numimtlaroides 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. suborbicularis Grun. (1880). — As var. nummularia, but witb doser striee, 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. 0,03 to 0,o6; B. 0,oi2 to 0,oi8 mm. Striee 

 15 to 22 in 0,oi mm. — Atl. LXX f. 12 to 16. iV. forc. 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. forcijiatu and N. pygmcea, so that the latter might be regarded as 

 a variety of N. forcipata. 



Var. balnearis Grun. (1880). — V. linear-elliptieal. L. 0, 037; B. 0, 01 mm. Lateral areas 

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

 mm. — N. pygm. rar. balnearis Grun. in V. H. Syn. X f. 8. 



Slightly brackish water: Sweden, Ronneby, fossil! 



Additional. 



N. seriösa Pant. (III Pl. XXXII f. 464). — Elliptical, rostrate-acuminate. L. 0,04 7; B. 0,o33 

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

 the middle and convergent at the ends. Striai 12 in 0, 01 mm. distinctly punctate. 



Marine: Hungary, fossil (Pant.). 



Naviculse Lsevistriatee Cl. 



Valve in outline more or less lanceolate. Axial area linear, abruptl}^ dilated around the 

 central nodule to an orbicular space, or transverse fascia, or uniting vs^ith the central area in a 

 more or less broad, lanceolate space. Striee 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 seotion is remarkable for its apparently smooth strise, and might on that account have 

 been placed in tlie genus Pinntil«ri((. But mo.'^t of the species bear a closer relationship to the 

 true Navicuhc thaii to the Pinnularitc, and, besides, it is possible that the stritt inay be only 

 apparently smooth. Nar. palpchralis, which I place in the section, is usually described and figured 

 as having distinctly jniiictate striiu, but T have never been able to detect any punctate character 

 in its striai. It does iiovvever contain several forms (as for instance N^ar. bituminosa) wliich are 

 closely related to sjjfcies 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 Entoleia of Navicula. 



