422 CH/ETOCEROS. 



Valve elliptic, having at each apex a long awn, with an obtuse enlarged 

 apex, surrounded at the base with several acute and much shorter awns. 

 Girdle face of frustule elongated, quadrangular. Frustule slightly silicious, of 

 variable size, 3 to 6 c.d.m. in breadth. 



Mirine. Found in abundance on the sands at Blankenberghe, where the waves sometimes 

 leave it in the form of long brownish streaks. England (West., Stolt., Kitton). Scotland (Baxter 

 Coll., No. 2888), Holland (Suringar). 



Ch. Wighamii Brightw. (Q.J.M.S., 1856, iv., p. 10S, pi. 7, f. 

 19-36; H.V.H. At]., pi. 82, f. 1*), plate 18, fig. 604. 



Valve convex, oval, covered with small spines, having at each end two very 

 long acute awns. Frustules united into a long filament. Valve (in the 

 specimen observed), 2^5 c.d.m. in length, by 2 c.d.m. in breadth. 



Marine. -Very rare at Blankenberghe (2nd Basin). Floiting in the Scheldt ( H.V.H. ). 

 England (Kitton, Stolt., Norman). 



Ch. paradoxum CI. (Diat. Java, p. 10, pi. 3, f. 16). 



Valves flat, with raised centre, oval, horns flexed in the direction of the 

 minor axis, very flat, furnished with alternating elevations. Frustules united 

 in a chain, leaving between them two large elliptic oval apertures. 



Pelagic. Found floating at Java. Surface of Dee, England (Stolt.). 



var. Eibenii Grun. (H.V.H. Atl., pi. 82, f. 9, 10*) plate 35, 

 fig. 916. 



Centre not raised, interfrustular apertures longly elliptic, with lanceolate 

 apices. Length of valve, about 4 c.d.m. 



Pelagic North Sea (Eiben). Maritime Scheldt. (H.V.H.). 



Sub-genus II. BACTERIASTRUM. Valve circular, bearing on its 

 margins a circlet of long awns. 



Ch. (Bacteriastrum) varians Lauder (T.M.S., 1864, iv., 



n.s., p. 8, pi. 3, f. 1-6; Actiniscus Ehr. H.V.H. Atl., pi. 8o, f. 3-5*; 

 Type No. 445), plate 18, fig. 605. 



Valve circular, covered with more or less sparse granules, showing a 

 conspicuous median dot, and bearing on its margins a corona of long awns, 

 variable in number, with their ends often undulate, sometimes straight, 

 bifurcated in the individuals forming the median portion of the filament, 



