KONGL. SV. VET. AKADEMIENS HANDLNGAR. BAND 27. N:0 3. 185 



punctate. Lower V. with straight median line, ending near the margin. Its central pores some- 

 what distant. Axial area narrow; central large, orbicular. Striae 8 to 9 in 0,oi mm. slightly 

 radiate, not distinctly punctate. — Rhaphoneis quarn. G-run. Verh. 1862 p. 381 PL IV f. 24. C. 

 quarn. A. S. N. S. D. p. 93 PL III f. 15 to 16. Atl. CXCII, p. 20 to 24. Navkula Ovulum A. S. 

 N. S. D. PI. II f. 12. C. clavigera O'Meara M. J. (n. s.) VII PL VII f. 5? 



Marine: Greenland! Spitsbergen! Finmark! North Sea! Mediterranean Sea! Adriatic! Fossil: 

 Karand, Hungary (a small form L. 0,oi5 mm.)! 



11. A. Lilljeborgii Gbun. (1881). — Lanceolate, obtuse. L. 0,oi7 to 0,046; B. 0,oo8 toO,oi 

 mm. Upper V. strongly silicious, with lanceolate axial area, one third of the breadth of the valve, 

 with coarse scattered granules. Costse 8 to 9 in 0,o i mm., slightly radiate, not punctate. Lower 

 valve thin, with lanceolate narrow axial area. Striae 12 in 0,oi mm., radiate in the middle, 

 where some are of unequal length, parallel at the ends, finely punctate. — Bot. Centralbl. 1881 

 p. 68. Cl. a. M. D. .N:o 102, 311. Diatomiste II PL III f. 19, 20. 



Marine: Grip and Bergen, Norway! He de Brehat, the Channel (Grunow). 



12. C. Lagerheimii Cl. (1893). — Outline elliptical. L. 0,o2to0,o28; B. 0,oi to0,oi5mm. 

 Upper V. with lanceolate axial area, having in its middle two longitudinal rows of coarse puncta. 

 Striae costate, 8 in 0,oi mm., the two median unilaterally united into a horseshoe-like marking. 

 Lower V. delicate with straight median line. Central area uniting with very large lunate lateral 

 areas. Striae fine, 25 in 0,oi mm. — Diatomiste H PL III f. 21, 22. A. S. Atl. CXC, 46? 



Fresh water: Ecuador, Sn. Nicolas, reg. trop.! 



Actinoneis Cl. N. G. 



Outline rhomboid to lanceolate. Valves very dissimilar. Upper valve with strong costae 

 and narrow axial area. Lower valve delicate, with finely punctate and strongly radiate striae. 

 No marginal rim. 



This group comprises a number of peculiar diatoms, the upper and lower valves being ex- 

 ceedingly dissimilar. The lower valves are finely punctate-striate and the striae are usually alter- 

 nately longer and shorter in the middle, and strongly radiate throughout. Valves of such a cha- 

 racter are met with only in the group of Navieulce microstigmaticce and heterostichce, and in a less 

 degree in the Navieulce Uneolatm {Nav. Gastrum for instance). 



Artificial key. 



I Upper valve with an unilateral horseshoe-shaped marking '2. 



' \ — — without — — — — — 3- 



( Lower valve with lateral areas A. inopinata Cl. 



\ — — without — — A. heteromorpha Geun. 



j Axial area of the upper valve lanceolate -A. Lorenziana Gbun. 



' \ — — — — — narrow linear 4. 



/ Valve apicnlate or rostrate 5- 



t - not — — 6. 



j Costs 6 in 0,01 mm A. mammalis Casts. 



\ 19 A. dispar Cl. 



( Valve short, rhomboid A. haldjikii Btw. 



I — elongated — or lanceolate '■ 



j Axial and central area of the lower valve indistinct . . . . A. Clevei Geun. 



\ — — — — — — — distinct .... 8. 



J Axial area suddenly dilated to a fimbriate central area .... .A. danica Flogel. 



^- \ — — lanceolate A. hottniea Cl. 



Kon-'l. Sv. Vet. Aknd. llandl. Band 27. N:o 3. 24 



