V 



A FOSSIL MARINE DIATOMACEOUS DEPOSIT. 325 



B. elegantula, Grev. (" T. M. S.," Vol. xiii, p. 50, PI. 6, Figs. 

 12). — Scarce, but identical with Greville's species. 



B. punctata, Grev. (" T. M. S.," Vol. xii, p. 83, PI. 11, Fig. 

 10). — Resembles closely Greville's form, but more oval. Rare, 



B. Oamarvensis, Gr. and St., n. sp. — Valve elliptical- oval, with 

 a central elevation ; the whole valve covered with fine-radiating 

 lines of granules and numerous interspersed minute puncta. On 

 each side of the centre opposite to one another are two large spines; 

 processes inflated, at the base, truncate. Distance between the 

 processes, -0053" ; breadth, -0023". (PI. XVIII, Fig. 10.) 

 Rare. 



B. elaborata, Gr. and St., n. sp. — Valve broadly oval, convex. 

 At the centre, which is inflated, is a circle of small close-set 

 papillae surrounded by a clear space, from which radiating lines of 

 round cellules run to the margin. The cellules near the centre 

 are smaller, but become larger towards the margin. Between each 

 row of these large cellules is a line of small dots. Two long stout 

 stalks terminating in a cup-like striated expansion project from the 

 valve, starting from circular clear spaces on each side. Length, 

 •0083"; breadth, -0054"; length of stalk, -0025". (PL XVIII, 

 Fig. 9.) 



We have some hesitation in classing this very remarkable form 

 as a Biddulphia. It is allied to Greville's B. gigantea (" T. M. S.," 

 Vol. xii, p. 13, PI. 2, Fig. 9) from Barbadoes. The two forms 

 might well form a new genus. 



B. virgata, Gr. and St., n. sp. — Valve small, oval, convex, with 

 two well-defined transverse clear spaces, becoming inflated towards 

 the ends. Processes formed by two stalks, projecting from clear 

 spaces at the extremities of the valve. The stalks terminate in a 

 large spherical expansion, the surface of which is delicately punc- 

 tate. Surface of valve furnished at the centre with a transverse 

 band of scattered granules ; before each process is a similar band 

 of granules, but more crowded. Length, 0033" ; breadth, 

 •0024". (PI. XVIII, Fig. 11.) 



In the specimen we figure, the expansions are broken off. 



Cerataulus subangulatus, Gr. and St., n. sp. — Valve subtri- 

 angular with rounded angles ; inflated, with three submarginal pro- 

 cesses resembling those of C. turgidus, and 2-4 strong spines, 

 sometimes curved, or with forked ends between each process. 

 Surface composed of rough radiating granules, over a closely 



