KONGL. ÖV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 181 



stomosing with longitudinal costse, thns formiiig a net-work of quadrate alveoli. Lower V. with 

 indistinct axial area, small orbicular central area and 9 striiB in 0,oi mm., composed of distinct 

 puncta, about 9 in 0,oi mm. — Pl. III f. 6, 7. 

 Marine: Galapagos Islands! 



4. C. formosa Brun (1891). — L. 0,07.5 to 0,i; B. 0,0.5 to 0,07 mm. Upper V. with narrow, 

 lanceolate axial area, and sliglitly radiate costse, 5 in 0,oi mm., anastomosing into a net-work of 

 rectaiigular alveoli, 4 in 0, 01 mm. Lower V. with straight median line, and indistinct axial area. 

 Central area transverse, narrow lanceolate. Terminal areas small and near the margin. Strise 

 6,5 in 0,01 mm. slightly radiate, coarsely punctate (puncta 8 to 9 in 0, 01 mm.) and ending with 

 donble rows of pnncta. — D. espéces nouv. p. 16 Pl. XVIII f. 6. Pant. III Pl. XXXII f. 457. 

 A. S. Atl. CXCIII, 42 to 47. 



Marine: Japan, fossil (Brun Coll.)! Indian Ocean (Brun), Wembats (Pant.). 



A peculiar form, the lower valve of which resembles C. costata, from which it difFers by 

 the absence of a marginal annulus. There is also sonie resemblance to C. vemicolor, but the upper 

 valves are entirely dissimilar. 



5. C. versicolor Brun (1891). — Elliptical. L. 0,o5 to 0,o65; B. 0,035 to 0,o4 mm. Upper 

 V. with narrow, lanceolate axial area, and strongly radiate costte, 5,5 in 0,(ii mm. Intercostal 

 spaces transversely lineate, lineolaB 13 in 0, 01 mm. Lower V. with straight median line reaching to 

 the margin. Axial area indistinct; central area narrow, transverse. Strise 7 in 0, 01 mm. slightly 

 radiate, jjunctate; puncta 14 in 0, 01 mm. Median stritE shorter than the others. — D. espéces 

 nouv. p. 19 Pl. XVIII f. 1. A. S. Atl. CXC f. 12 to 14. 



Marine: Japan, fossil (Brun Coll.)! Mogador (Brun). 



(i. C. pinnata Greg. (1859). — Elliptical. L. 0,024 to 0,04; B. 0,oi9 to 0, 03 mm. Upper 

 V. with broad, axial area and strong, slightly radiate costte, 4 to 5 in 0, 01 mm. Intercostal 

 spaces with double rows of puncta, arranged in oblique lines. Lower V. as in Cocc. pseudo- 

 marginata, but smaller and with closer striation (according to Grunow). — C. pinnata Greg. M. 

 J. VII p. 79 Pl. VI f. 1. V. H. Syn. Pl. XXX f. 6, 7. A. S. Atl. CLXXXIX f. 1 to 5. C. 

 Loremiana Pbrag. D. de Villefranche Pl. V f. 38? G. denticulata Leud. Fortm. D. de Ceylon 

 Pl. I f. 2? Rhaphoneis Archeri 0'Meara Quek. M. J. Vol. VII ser. 2 Pl. VII f. 12? 



Marine: Spitsbergen! Finmark! North Sea! Mediterranean Sea! Adriatic! Seychelles! Island 

 of Ehea near Singapore! 



Pleuroneis Cl. N. G. 



Frustules with a marginal rim. Valves broadly elliptical to orbicular. Upper valve with 

 more or less narrow axial area and radiate costse, alternating with double rows of puncta, forming 

 oblique, decussating lines. Lower valves with radiate rows of finer puncta. 



1. €. britannica N^geli (1849). — Bi-oadly elliptical. L. 0,025 to 0,05; B. 0,022 to 0,037 

 mm. Upper V. with very narrow axial area. Costfe (5 to 10 in 0, 01 mm., alternating with double 

 rows of small puncta (about 18 in 0,oi mm.) forming oblique lines. Lower V. with distinct median 

 line, not reaching to the margin. Axial area indistinct. Central area very small and orbicular. 

 StricB about 10 in 0, 01 mm. Rim with about 5 costee in 0, 01 mm. — C. hrit. Kutz. Sp. Alg. 

 p. 890. V. H. Syn. Pl. XXX f. 1, 2. C. coronata Btw. M. J. VII p. 179 Pl. IX f. 2? G. pseudo- 

 marginata Jan. Rab. Honduras D. Pl. I f. 16? G. scutelliformis Grun. in Cl. M. D. 148, 154, 208 

 —210. G. costata var. A. S. Atl. CLXXXIX f. 8? G. eximia A. S. Atl. CXCII f. 31? 



Marine: Mediterranean Sea! Adriatic (Grun.)! Barbados! 



This species resembles, under a low power, G. Scutellum, from which it is however widely 

 different. C. Ningpoensis Petit (Mém. Soc. Cherbourg XXIII p. 207 Pl. I a, 1881) perhaps repre- 



