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



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



4. 



{ 



»I 



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



) — not — — — — — — 6. 



j L. 0,04 to 0,047 mm A. granulifera Cl. 



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



I Ends of the valve reflexed A. Janischii A. S. 



\ — — — not — 8. 



„ I Strise crossed by broad lateral areas A. margaritifera Cl. 



\ — not — — — — A. alata Per. 



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



— — - not — — — — 30. 



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



\ — transverse costae or rows of puncta 11. 



..^ J Ventral side of the valve without puncta or costae 12. 



1 - _ _ _ with - — 13. 



.^ I Costse 2,3 to 3 in 0,oi mm A. Pecten Bkun. 



^ \ — 10 in 0,01 mm A. inornata Cl. (.1. crassa var., A, egregia var.) 



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



nth. punotate or costate strise 15. 



Dorsal side with one longitudinal line A. Griindleri Geun. 



several — lines A. prismatica Cl. 



^P I Ventral side punctate 16. 



' ) — — costate 18. 



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



' \ — — — — — not — — — A. crassa Gkbg. 



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



j Costae 



12 in — — A. decipiens Cl. 



H,{ 



— — apparently smooth A. ornata Leud. Foetm. 



18. |^°_1*= 



..„ j Costse alternating with donble rows of puncta A. egregia Ehb. 



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



„. / Dorsal side with two longitudinal lines 21. 



' \ — — — one — line 22. 



„.. t Axial area 



rea indistinct A. areolata Grun. 



distinct A. Leudugeriana Pet. 



gn I Longitudinal line approximate to the median line A. diaphana Cl. 



' \ — — distant from — — — 23. 



yq J Space between the median and longitudinal lines suddenly dilated in the middle . . 24. . 

 ' \ — — — — — — not — ■ — — — .... 26. 



f Central area structnreless 25. 



24. < — — with scattered puncta A. subpunctata Grove a. Sturt. 



I — — — faint striae A. bioculata Cl. 



g, J Dorsal margin arcuate A. gemDiifera Petit. 



"^ ' i — — sinuose A. SturtM Grun. 



yi; I Central nodule dilated to a stauros A. capensis A. S. 



' \ — — not stauroid 27. 



„.. I Ends of the valve protracted 28. 



■ t — — — not - 29. 



„£, J Striae reaching to the longitudinal line A. proboscidea Cl. 



I — -" across — — ^1. Grevillcana Greg. 



y(. I Stria) l!l to 20 in 0,oi mni A. truncata Cl. 



,., I L. 0,0.5 to 0,i)i; mm ,1. .<iHkata Cl. 



) L. 0,1 to 0,13 mm .4. Grae.ffii Cl. 



1. A. UecipiciiS Cl. N. Sp. — Frnstule iiearly rectangnlar, about 3 times as loiig aw broad. 

 Vi. n.dSD; B. 0,02 inin. Zone with di.stant rows (6 in 0,0 1 mm.) of puncta (aboiit 11 in 0,oi mm.). 

 V. gibbous in tlu- iiiidcUe of the ventral margin. L. 0,o.i.^> to 0,o6; B. 0,02 mm. Ends obtuse. 

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



