KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:() 2. 7.') 



1. N. iiicobsiricji Grun. (1803). — V. broadly elliptical. L. (),i)244 to (J,(i4:i; J3. U.or.i to 

 0,03 mm. Median line witli moderately approximate median pores and large comma-like terminal 

 tissures, tnrned in tlie same direction. Axial and central areas luiiting in a large lanceolate space, 

 having on both sides of the median line a rovv of large, sometimes confluent pnneta. Strite 7 to 

 8 in 0,01 mm. smooth, radiate tliroughout. — fxRUN. Verh. 1863 p. 150 Pl. V f. 8. A. S. Atl, VIII 

 f. 57, LXX f. 35, 36. Cl. Vega p. 505 Pl. XXXV f. 16. 



Marine: Ceylon! Nicobar Islands (Grnn.), Celebes (Atl.), Cajje of Good Hope (Atl.), Cape 

 Horn (Petit). 



'2. N. Ny Cl. N. Sp. — V. elliptical, with broad runnded ends. L. 0,u4; B. O, o is mm. 

 Median line with large comma-like terminal fissnres, tnrned in the same direction. Axial and 

 central area united in a large lanceolate area having on both sides of the median line a row of 

 small pnncta, and around the central nodule a few larger stigmas. Stria\ 16 in 0,oi mm., 

 apparently smooth. — Pl. I f. 24. 



Marine: Java! 



Cymatoneis Cl. N. G. 



Valve more or less elliptical or lanceolate in ontline, divided by oue or several longitndinal 

 ridges into two or more divisions. Median line with approximate central pores and elongated ter- 

 minal fissnres, at some distance from the ends of the valve. Axial area narrow, central small, 

 nsnally rhomboidal. Structnre: pnncta disposed in transverse and straight longitiidinal rows — 

 Zone not complex. 



This little gronp of very characteristic forms seems to be most nearly akin to Scolioplenra, 

 althongh no species has any very close connection with that genus. The structnre of the valve is 

 the same as in Scolioplenra Peisonis and the ridges on both sides of the median line rccall those of 

 Scolioplenra. In several forms there is a tendency in the median line to be sigmoid. 



1. C. Sillcatii Grev. (1863). — V. convex, with triundulated margins, and apiculate or sub- 

 rostrate ends. L. 0,045 to 0,ö6; B. 0, 025 to 0,033 mm. Axial area very narrow, dilated around 

 the central nodule to a rhomboidal space. Median line slightly sigmoid ; terminal fissnres elongated, 

 distant from the ends. Kidges two or three on each side of the median line. Strii-c radiate at 

 the ends, 8 to 11 in 0, 01 mm.; pnncta forming straight, longitndinal rows, 14 to 18 in 0,oi mm. 

 — Navic. sulcata Grev. Träns. Bot. Soc. Edinb. Vol. VIII p. 235 Pl. III f. 10. Leud Fortm. D. 

 de Ceylan Pl. III f. 30. Nar. triiindulata Grun. Hedwigia VI p. 27 (1867). M. M. J. 1877 Pl. 

 CXCV f. 10. Cymaton. sulc. Pl. I f. 12, 13. 



Marine: Mediterranean Sea! Seychelles (V. H. Coll.)! Madagascar (V. H. Coll.)! Ceylon! 

 Labuan! Japan! Port Jackson! Java! China! Ja])an! New Caledonia (Grev.), Galapagos Islands! 

 Honduras (Grun.), Campeachy Bay! West Indies! Florida! 



Varies occasionally with a slight constriction in the middle and with quadri-undulated margins. 



2. C. quadrisiilcata Grun. (1867). — V. elliptic-lanceolate, with slightly rostrate, obtuse 

 ends. L. 0,o5 to U,o',i; B. 0,o28 to 0,036 mm. Axial area indistinct; central area orbicular. Ridges 

 two on each side of the median line. StrifP slightly radiate, 6 to 8 in O.oi mm., punctate; pnncta 

 forming longitndinal rows. — Nac. qundris. Grun. Novara p. 101 Pl. I A f. 14. 



Marine: S:t Pauls Island. 



Grunow figures two specimens, which seem to belong to diflerent species. The smaller re- 

 sembles C. sulcata and may be a non-undulated variety of that species. The larger may be iden- 

 tical with the foUowing, bnt I cannot identify them, as Grunow's figure shews two ridges of equal 

 strength on both sides of the median line. 



