108 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 





Ends of the valve broad and incurved . . ... . .A. vetusta Cl. 



— not — — ... . ... 5. 



Zone dissimilar on the dorsal and ventral side .... . A. cuneata Cl. 



not — — — — — — . . . 6. 



^ I L. 0,04 to 0,047 mm. ...... . A. granulifera Cl. 



1 L. 0,1 to 0,113 mm. ..... A. Weissflogii A. S. 



„ ( Ends of the valve reflexed ... ... .A. Janischii A. S. 



■ \ — — — not — . . . . . . . 8. 



o ( StriEB crossed by broad lateral areas . . A. margaritifera Cl. 



I — not — — — — , A. alata Pee. 



„ J Ends of the valve broad, obtuse, or incurved 10. 



\ — — — not — — — — . . 20. 



..„ 1 Structure: quadrate alveoli in longitudinal and transverse rows A. tesselata Grove a. Sturt. 



\ — transverse costae or rows of puncta .... 11. 



Ventral side of the valve without puncta or costse ... . 13. 



with — — .... 13. 



-n J Costae 3,3 to 3 in 0,oi mm.. .... .A. Pecten Bbun. 



I 



10 in 0,01 mm A. inornata Cl. {A. crassa var., A. egregia var.] 



{ 



..„ 1 Ventral side with two longitudinal rows of puncta . . . 14. 



with punctate or costate striae . . . . 15. 



. . ( Dorsal side with one longitudinal line . . . . A. Grundleri Geun. 



\ — — — several — lines A. prismatica Cl. 



... f Ventral side punctate 16. 



1 — — costate ... ... 18. 



..„ / Rows of puncta on the ventral side crossed by a blank band . . 17. 



not — — — . A. crassa Greg. 



Dorsal striae of large, distant puncta .... A. comorensis Cl. 



— — apparently smooth . .... A. ornata Letjd. Eohtm. 



..„ J Costae 4 to 7 in 0,01 mm. . . . .... . 19 



17. I 



{■ 



I Costa 



I — 12 in — — . . .A. decipiens Cl. 



alternating with double rows of puncta . .A. egregia E 



not — — — — — . . A. inelegans Cl. a. Grc 



Dorsal side with two longitudinal lines ... ... 21. 



21. {^^"' 



.,„ I Costse alternating with double rows of puncta . .A. egregia Ehb. 



I — not — — — — — . . A. inelegans Cl. a. Grove. 



20. I 



[ — — — one — line . . . . , . 22. 



Axial area indistinct .... . . A. areolata Grtjn. 



distinct .... , . .A. Leudugeriana Pet. 



(,„ I Longitudinal line approximate to the median line . . ■ . . . A. diaphana Cl. 



' \ — — distant from — — — 23. 



,,„ j Space between the median and longitudinal lines suddenly dilated in the middle . 24. 



■ I — -- _ _ _ _ not — — — — .... 26. 



{Central area structureless 85. 



— ^ with scattered puncta . . . . . . A. subpunctata Grove a. Sturt. 



— -^ — faint striae .... ... . . . A. Uoculata Cl. 



26 I ^"^^'^^ margin arcuate . . A. gemmifera Petit. 



f,^ ( Central nodule dilated to a stauros . . . A. capensis A. S. 



~^ \ — — not stauroid 27. 



„- I Ends of the valve protracted . 28. 



■ I — — — not - 29. 



gg I Stria) reaching to the longitudinal line A. proboscidea Cl. 



' I — — across — — A. Grevilleana Greg. 



on i Striae 19 to 20 in 0,0 1 mm. A. truncata Cl. 



^^- t - 11 to 14 - - 30. 



^Q i L. 0,05 to 0,06 mm. . A. sulcata Cl. 



(L- 0,1 to 0,13 mm A. Graeffii Cl. 



1. A. decipiens Cl. N. Sp. — Frustule nearly rectangular, about 3 times as long as broad. 

 L. 0,0.55; B. 0,02 mm. Zone with distant rows (6 in 0,oi mm.) of puncta (about 11 in 0,oi mm.). 

 V. gibbous in the middle of the ventral margin. L. 0,o35 to 0,o6; B. 0,02 mm. Ends obtuse. 

 Axial area distinct on the dorsal and ventral side, somewhat dilated in the middle. Crest or 



