174 p. T. CLEVE, SYNOPSIS OP THE NAVICULOID DIATOMS. 



„ ( Median line sigmoid 10. 



'[ — — straight . . . • ,13. 



^|, ( Valve with an annnlus at the side of the centre C cyclophora Geun. 



\ — without 11. 



coarse (9 to 11 in 0,oi mm.) 12. 



fllne (25 — — — ) C heteroidea Hantsch. 



..„ j Central nodule transversely dilated C. arctica Cl. 



■ \ — ^ not — — C. valuta Be. 



..^ f Striae of the upper valve coarse (9 to 11 in 0,0 1 mm.) 12. 



13. 



( Lateral areas connected to a broad marginal annulus ... 14. 



1 — — not — — — — — 15. 



^ . ( Striae of the upper valve composed of coarse puncta ... . . . C. antiqua Bb. 



' \ • — — — — costate with a median punctum . . C. interrupta Getjn. 



I F. I Upper valve with longitudinal furrows or depressions . 16. 



' I — — without 18. 



.,„ j With several, strong furrows . . . C. pellucida Hantsch. 



r, I With severs 



' ( — — a lunate depression . 17. 



f Stria 



J Later 



._ (Stria fine (16 to 24 in 0,oi mm.) punctate C. pseudomarginata Geeg. 



\ — coarse (10 in 0,oi ram.) costate, with a median punctum C. vitrea Beun. 



^„ J Lateral areas crossed by two oblique rows of pnncta C. prcecellens Pant. 



- not — — — — — — C. Letourneuri Cl. 



1. C. niolesta (Kutz. 1844) G-kun. (1881). — Outline elliptical, with broad, rounded ends. 

 L. 0,017 to 0,019; B. 0,oo7 to 0,oo8 mm. Upper V. with narrow axial area. Strise more than 30 

 in 0,01 mm. finely punctate, puncta forming zig-zag-lines. Lower V. with straight median line, 

 not reaching to the ends. Central area very small. Strise more than 30 in 0,o i mm. punctate, puncta 

 forming fine, longitudinal strise. — Bac. p. 71 PI. V f. 7, 11, 12. V. H. Syn. PI. XXX f. 18, 19. 

 A. S. N. S. D. PL III f. 20? 



Marine: Venice (Kiitz.). 



Var. crucifera (jRUN. (1881). — L. 0,oi5 to 0,025; B. 0,oo8 to 0,oi6 mm. Central area of 

 the lower valve dilated to a transverse fascia. — V. H. Syn. PL XXX f. 20, 23. U. diaphana 

 W. Sm. B. D. p. 22 PL XXX f. 254 (partim) 1853. A. S. Atl. CXCIII, 48 to 51. 



Marine: England! Coasts of France! 



Var. amygdalina (Br^b.) Gbun. (1881). — L. 0,035 to 0,045; B. 0,oi3 to 0,02 mm. Upper 

 V. with about 20 strise in 0,oi mm. Lower V. with slightly dilated central area and about 27 

 strise in 0,oi mm. — 0. diaphana W. Sm. B. D. I p. 22 PL XXX f. 254 (partim). G. amygdalina 

 Grun. in V. H. Syn. XXX f. 5. 35. 



Marine: French coast of the English Channel! 



2. C. finmarchica Grun. (1880). — Elliptical. L. 0,012 to O-ois; B. 0,0055 to 0,oo7 mm. 

 Upper V. with linear axial area. Strise 20 in 0,oi mm. slightly radiate. Lower V. with straight 

 median line, ending near the margin. Central area a fascia, not reaching to the margin. Strise 24 

 in 0,01 mm. slightly radiate. — A. D. p. 16 PL I f. 1. 



Marine: Arctic America! Finmark! 



3. C. septentrionalis Grun. (1884). — Elliptical. L. 0,022 to 0,o36; B. 0,012 to 0,023 mm 

 Upper V with narrow axial area. Strise 8 in 0,oi mm. almost parallel, punctate; puncta 14 in 

 0,01 mm., larger at the margin, not arranged in longitudinal rows. Lower V. with straight 

 median line. Central area a narrow, transverse fascia. Strise radiate, 9 in 0,oi ram. punctate; 

 puncta 16 in 0,oi mm. — Franz Josefs Land D. p. 55 PL I f. 2. 



Marine: Assistance Bay (Grun.). 



4. A. Calcar Cl. (1891). — Broadly elliptical. L. 0,012; B. 0,oo9 mm. Upper V. with 

 straight, narrow axial area. Central area on one side of the nodule dilated into a spurlike pro- 

 jection, on the other bifid, forming an horseshoe-like marking. Lower V.(?) with straight median 



