68 



Nar. hitumiiiosa is a variable species, which is closely akin to Finnularia, sectioii äivergentes. 

 On the other hand some of its varieties seem to be akin to varieties of Nav. Yarrensis. The areas 

 are subject to great variation, and there are gradual passages from forms with a perfect trans- 

 verse fascia, to forms with the central and axial areas nniting in a lanceolate space. As the 

 mest extreme form of this kind I regard Nav. cincta Pant,, which I know only by the figure in 

 Pantocsek's work. Pantocsbk considers it as a distinct species, and if so another name is neces- 

 sary, as the name cincta has been used for another, well known species. 



2. N. Cli.vzereii Pant. (1889). — V. elliptic-lanceolate, with obtuse extremities. L. 0,oBii; 

 B. 0,019 mm. Axial area distinct, linear, abruptly dilated to an orbicular central area. Strise 8 

 to 10 in 0,0 1 mm. divergent in the middle, convergent at the ends. — Pant. II p. 43 Pl. V f. 96. 



Brackish water: Hungary, fossil! 



3. N. discernenda Pant. (1889). — V. linear-elliptical, with subciineate ends. L. 0,o.3 7 to 

 0,0 5; B. 0,0 12 to 0,0 13 mm. Axial area very narrow; central area large, orbicular. Strine 12 to 

 14 in 0,01 mm. divergent in the middle, convergent at the ends. — Pant. II p. 45 Pl. XXII f. 335. 



■ Brackish water: Hungary, fossil! 

 N. clisceriienda is closely akin to N Chysereii and scarcely more than a small variety with 

 somewhat closer striee. 



4. N. gråta Pant. (1889). — V. narrow, elliptic-lanceolate. L. 0,084; B. 0,oi5 mm. Median 

 pores distant. Axial area narrow linear, strongly dilated in the middle. Striae. 11 in 0,oi mm., 

 divergent in the middle, convergent at the ends, their terminations angularly bent. — Pant. II 

 p. 46 Pl. II f. 21. 



Brackish water: Hungary, fossil (Pant.). 



5. N. elegans W. Sm. (1853). — V. lanceolate, with acute ends. L. 0,i; B. 0,o27 mm. 

 Median line with distant central pores aud semicircular terminal fissures. Axial area very narrow; 

 central area large, orbicular. Strite 9 in 0,o i mm., strongly divergent in the middle, convergent 

 at the ends. — Br. D. 1 p. 49 Pl. XVI f. 137. Donk. Br. D. p. 23 PL IV f. 1. 



Marine to brackish: England! Bohuslän! 



Var. cii-spidata Cl. — V. rostrate. L. 0,08; B. 0,02 mm. Stripe closer, abont 12 in 0,oi mm. 



Brackish water: Atlantic eoast of North America! 



6. N. laiita Grun. (1888). — V. linear-elliptical, with subciineate ends. L. 0,oy5; B. O, oas 

 mm. Axial area lanceolate, dilated in the middle. Median line with the terminal fissures in 

 contrary directions (Grun.). Stria; 13 (9 to 10 Grun.) in 0,oi mm. divergent in the middle, con- 

 vergent at the ends, in the middle alternately longer and shorter. — V. H. Types 542 Bot. 

 Centralbl. XXIII p. 324. Icon. n. Part. I Pl. I f. 30. 



Brackish water: South Yarra, Australia! 



7. N. iTiegastauros Cl. (1883). — V. elliptic-lanceolate, with subacute ends. L. 0,02; 

 B. 0,008 mm. Axial area indistinct; central large, transverse, dilated to a stauros, reaching nearly 

 to the margin. StrifE 16 in 0,01 mm., strongly divergent in the middle, transverse at the ends. 



Vega p. 464 Pl. XXXV f. 19. 

 Marine: Cape De.schnetf! 



Stauroneis delicatula Levd. Fortm. (Ceyl. p. 36 Pl. III f. 34, 1879) is twice as large as 

 N. megadauros and seems to be akin to it. 1 have not seen this specnes. 



«. N. lialionata Pant. (1H86). — V. lanceolate, gradually tapering from the middle to the 

 obtiti^f (•lids. L. 0,12 to 0,22; B. 0,0:) to 0,048 mm. Area broad, lanceolate. Striii; 8 to 9 in 0,oi 



