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



( Central pores approximate A. bipunctata Grun. 



\ — distant — A. zellensis Grun. 



„ ( Central area a transverse fascia A. Macraeana Pant. 



' \ — — not dilated 8. 



I Ends acute A. serians Bréb. 



( — obtuse 9. 



„ ( Larger forms. L. 0,1 mm A. polygramma Ehb. 



t Smaller — L. 0,02 to 0,03 mm A. hrachysira Grun 



1. A. sphaerophora Kutz (1844). — V. elliptic-lanceolate with rostrate-capitate ends. 

 L. 0,0 5 5 to 0,0 8; B. 0,oi7 to 0,0 2 mm. Axial area narrow, linear. Central area irregularly 

 rounded, larger on one side of the valve than on the other. StritB slightly radiate thronghout, 

 16 in 0,0] mm. — Navic. sphcerophora KtJTZ Bac. p. 95 Pl. IV f. 17. W. Sm. B. I). I Pl. XVII 

 f. 148. V. H. Syn. p. 101 Pl. XII f. 2. A. S. Atl. XLIX f. 49-51. 



Fresh or .-slightly brackish water: Sweden! England! Switzerland! East Indies! New Zealand! 

 Illinois! Giiatemala! West Indies (St. Martin! Jamaica!) Ecuador! 



Var. hiceps Ehb. (1843). — Smaller. L. 0,o4; B. 0,oi3. StrifB finer. — Nav. biceps Ehe. 

 Am. p. p. ScHUM. I Nachtr. p. 21 f. 26. A. S. Atl. XLIX f. 52. N. spliceroph. v. minor V. H. 

 Syn. Pl. XII f. 3. N. sphceroph. subcap. GtRUN. Foss. D. Öst. Ung. p. 157. 



Slightly brackish water: Franzenbad (Atl.), Eger foss! 



2. A. sciilpta Ehb. (1840). — V. lanceolate, with protracted, rostrate, and obtuse ends L. 0,o7 

 to 0,1 ; B. 0,025 to 0,036 mm. Axial area narrow, linear, bordered by a single row of puncta, 16 

 in 0,01 mm. Central area uniting with large, lunate lateral areas, of which one expands in the 

 middle to the margin. StriiB 15 to 16 in 0,oi mm., slightly radiate, distinctly pnnctate; pnncta 

 crowded near the margin, distant towards the lateral areas, where they are arranged in oblique, 

 somewhat undulating rows. — Nav. sculpta Ehb. Ber. 1840 p. 18. M. Gr. X: i, f. 5. Fresenius 

 Senckenb. Abh. IV Pl. IV f. 14 to 16. A. S. Atl. XLIX f. 46 to 48. V. H. Syn. p. 100 Pl. XII 

 f. 1. Pant. II, XI f. 191. N. rostrata Kutz. Bac. p. 94 Pl. III f. 45 (1844). Donk. B. D. p. 15 

 Pl. II f. 9. Grun. Verh. 1860 p. 540. N. tumens W. Sm. B. D. Pl. XVII f. 150 (1853). 



Brackish water: Baltic! Franzenbad! Mansfelder Seen! Neusiedler See (Grun.), Belgium 

 (V. H.), S:ta Fiora (Ehb.), England! Hungary fossil (Pant.), New Zealand! Ecuador! 



Var. major Cl. — L. 0,i2 to 0,i5; B. 0,04 to 0,o5 mm. Lateral areas almost similar. 

 Striae 13 in 0,oi mm. 



Brackish water: S:ta Rosa, Calif. (Grove Coll.)! Guatemala, fossil! 



A. .^culpfa is nearly akin to A. s2)liceropliora, from which it is distinguished by larger size 

 and the large, lunate lateral areas, which are in typical specimens somewhat dissimilar, one of 

 them extending in the middle to the margin. A. sculpta is also related to A. polygramma, together 

 with which form it usnally occurs, and which differs by its not protracted ends. Both are 

 to be considered as forms of the same species. 



3. A. polygramma Ehb. (1843). — V. narrow-elliptical, with obtuse, not protracted ends. 

 L. 0,08 to 0,13; B. 0,023 to 0,03 mm. Axial area narrow, linear, bordered with a single row of 

 puncta. Central area transverse, uniting with narrow, somewhat asymmetrical lateral ai'eas. StriiB 

 about 14 ill O.oi mm. very slightly radiate thronghout and composed of distant puncta, arranged 

 in longitudinal, undulating rows. — Sfauroncis polygrnmma Ehb. Am. Il: 6, f. 30. Nav. costata 

 KöTZ. Bac. p. 93 Pl. III f. 56 (1844). N. hnhemica Ehb. Mic. G. X: 1 f . 4 a (1854). Fresenius 

 Senckenb. Abh. IV Pl. IV f. 10 to 13. A. S. Atl. XLIX f. 43 to 45. N. fossilis Ehb. Mic. G. 

 X: I, f. 6 (1854). N. pannonica Giiux. Verh. 1860 p. 541 Pl. IV f. 40. N. trigranima Fresenius 

 Senckenb. Abh. IV Pl. IV f. 1 to 9 (IX()2). 



Brackish water: Sweden! Franzenbad! Eger! Neusiedler See (Crun.), Catania fossil (Grun.), 

 Cuba (Ehb.), Utah! 



