108 p. T. CLEVE, SYNOPSIS OK THE NAVICUEOII) DIATOMS. " 



Ends of the valve liroad ami incurved A. vetustn ("l. 



— — — not — — 5. 



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



not — — — — — — 6. 



. j L. 0,04 to 0,04 7 mm A. grannlifera Ol. 



\ L. 0,1 to 0,113 mm - A. Weissjlogii A. S. 



j Ends of the valve retlexed A. Janischii A. S. 



' \ — — — not — 8. 



o j Striae crossed by broad lateral areas A. margaritifera Cl. 



\ — not — — — — A. alata Per. 



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



- not — — — — 30. 



^^ , Structure; quadrate alveoli in longitudinal and tr;insverse rows A. tes.selafa Grove a. Sturt. 



transverse costie or rows of jiuncta 11. 



^. . Ventral side of the valve without puucta or costa 12. 



^ ^ _ _ __ with - — 13. 



(,'ostw 2,3 to 3 in 0,0 1 mm A. Pecten Brun. 



10 in 0,01 mm A. inornata Cl. (^4. crassa var., A. egregia var.) 



^.^ j Ventral side with two longitudihal rows of puncta 14. 



\ — — with punctate or costate stria 15. 



. , j Dorsal side with one longitudinal line A. Grilndleri Grun. 



I — — — several — lines A. prisntaticn Cl. 



Ventral side punctate 16. 



9. { I^™' 



'■I 



12. <! '■" 



{ 



^ , J Rows ot puncta on the ventral side cr 

 I — — — — — not 



18, 



— apparently smooth ^l. ornata Leud. Fortm. 



Costse 1 to 7 in 0,oi mm 19. 



( Cost 



15. 



— costate 18. 



ossed by a blank band 17. 



t — — — A. crassa Greg. 



^_ j Dorsal striae of large, distant puncta .4. coinorensis Cl. 



B 



12 in — — A. decipiens Cl. 



.(f, j Costae alternating with double rows of puncta A. egregia Ehb. 



1 — not — — — — — .4. inelegans Cl. a. Grove. 



„ j Dorsal side with two longitudinal lines 21. 



I — — — one — line 22. 



„- I Axial area indistinct A. areolata Grun. 



) — — distinct ^4. Leudugeriana Pet. 



4,.^ j Longitudinal line approximate to the median line A. diaphana Cl. 



\ — — distant from — — — 23. 



yn i '^P^'^*' between the median and longitudinal lines suddenly dilated in the middle . . 24. 



t — . — — — — not — - — — .... 26. 



f Central area structureless 25. 



24. < — — with scattered puncta ^4. suhpunrtata Grove a. Sturt. 



\ — — — faint striffi .4. bioculata Cl. 



„, I Dorsal margin arcuate ^1. gemniifera Petit. 



— — sinuose A. Stnrtii Grun. 



„, 1 Central nodule dilated to a stauros A. copensis A. S. 



not stauroid 27. 



d 28. 



29. 

 StriiB reaching to the longitudinal line A. proboscidea Cl. 



— — across — — A. Grevilleona Greg. 



(( . Stria; 19 to 20 in 0,oi mm ^4. fricncata Cl. 



■^ 11 to 11 — — 30. 



„, I L. 0,0.'') to 0,oii mm .4. sulcata Cl. 



I l>. 0,1 to 0,1;) mm A. Graeffii Cl. 



^,_ j Ends of the valve protractei 

 " I — — — not -- 



28. I 



{ 



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

 L. 0,0-).'); B. 0,0-i nun. Zone with distant rows (6 in 0,01 mm.) of puncta (about 11 in 0,(ii mm.). 

 V. giljlxMis in the middle of the ven-tral margin. L. (),(i;!.'') to (),oti; P>. 0,oi> mm. Ends obtuse. 

 Axial area distinct 011 the dorsal and \'entral side, somewhat dilated in the middle. Crest or 



