KONGL. SV. VET. AKADEMIENS HANDLINGAE. BAND. 27. N:0 3. 67 



Thus, it appears that the forms of the IcBvistriate are intermediate between the Pinnularife and 

 the true NaviculiE. 



The species of this group are usually inhabitants of brackish water and ^stuaries, but 

 there are also purely marine forms among them. 



Artificial Jcey. 



i Valve sigmoid X Rneana Castb. 



\ — straight g. 



I Axial area abruptlj' dilated into an orbicular central area or transverse fascia ... 3. 



\ Axial and central area uniting into a lanceolate or linear space 7. 



., I Median stri» of equal length 4. 



\ — — alternately longer and shorter N. lauta Grun. 



, J Central area orbicular 5. 



" \ — — a transverse fascia 6. 



^ I Valve acute or rostrate i\r. elegans W. Sm. 



i — obtuse iV. Chyzerei Pant, N. discernenda Pant., N. fjrata Pant. 



^ I Valve large. L. about 0,0(j mm X. bituminosa Pant. 



) — small. L. about 0,oa mm y. megnstauros Cl. 



_ J Valve triundulate .... N. Areschoiigiana Grun. {N. palpebralis v. Botteriana Grun.). 



■ 1 — not — 8. 



Q J Strise radiate throughout 9. 



1 Terminal strise convergent or parallel 19. 



Q I Median strise of equal length 10. 



' \ — — alternately longer and shorter 11. 



I Area very broad N. marginnlata Cl. 



) — medium sized N. palpebralis Bréb. 



I Area narrow N. Vahliana Grun. 



1 — rhombic-lanceolate N. solida Cl. 



J Valve elliptical N. Kochii Pant. 



I — lanceolate 13. 



.(„ I Strije coarse, distant, 4 to 8 in 0,oi mm iV. yarrensis Grun. 



\ — doser, 8 to 9 in 0,oi mm N. halionata Pant. 



1. N. bituminosa Pant. (1889). — V. linear-lanceolate, with subacuminate ends. L. 0,o65; 

 B. 0,014.5 mm. Central pores of the median Jine somewhat approximate. Axial area narrow, linear. 

 Central area a broad suborbicular fascia, almost reaching the margin. Strise 10 in 0,oi mm., 

 divergent in the middle, convergent at the ends. — Pant. II p. 42 Pl. VII f. 137. 



Brackish water: fliingary fossil! 



Var. latecvpitata Pant. (1889). — V. linear, with broad, rostrate ends. L. 0,064; B. 0,oi35 

 mm. Striae 8,5 to 9 in 0,oi mm. — Pant. II 1. c. f. 133. 



Brackish water: Gyöngyös Påta, Hungary fossil (Pant.). 



Var. robusta Pant. (1889). — V. with capitate-rostrate ends. L. 0,o85; B. 0,oi8 mm. Cen- 

 tral area lanceolate. Strise 10 to 11 in 0,oi mm. — Pant. II Pl. XI f. 202. 



Brackish water: Erdöbenye, Hungary, fossil (Pant.). 



Var. signata Pant, (1889). — V. linear-lanceolate, with obtnse ends. L. 0,o68; B. 0,oi s mm. 

 Central area a transverse fascia reaching nearly to the margin. Stria? 11 to 12, .5 in 0,oi mm. — 

 Pant. II p. 43. N. hit. v. valida Pl. V f. 89. 



Brackish water: Gryöngyös Påta, Hungary, fossil (Pant.). 



Var. staurophora Pant. (1889) — V. lanceolate. L. O, o. 5 4 to 0,07.5; B. O, o 1.3 to 0,oi5 mm. 

 Central area a broad fascia, reaching to the margin. Strise 10 to 11 in 0, 01 mm. — Pant. II 

 Pl. V f. 87, 88. 



Brackish water: Hungary fossil (Pant.). 



Var.? cinda Pant. (1889). — V. lanceolate, with obtuse ends. L. 0,075; B. 0,oi6 mm. 

 Area lanceolate, very wide. Strise 12,5 in 0,oi mm. — Nav. cincta Pant. II p. 44 Pl. XI f. 196. 



Brackish water: Hungary, fossil (Pant.). 



10. 

 11. 

 12. 



