232 GREVILLE, ON NEW DIATOMS. 
Hab. Barbadoes deposit, Cambridge estate; C. Johnson, 
Esq. 
The eranules are distinct and remote over the whole valve; 
not circular, but rather slightly quadrate, minute in the 
centre, but increasing in size as they radiate to the margin, 
which is striate. Pseudo-nodules vertical relatively to ‘the 
plane of the valve, obtuse, and extremely prominent. 
Triceratium disciforme, nu. sp., Grev.—Valve nearly circu- 
lar, with no perceptible pseudo- nodules; granules (rather 
cellules) very large, subquadrate, radiating, increasing in size 
from the centre to the margin, where the lines are 5 in ‘001”. 
Distance between the angles about ‘0035”. (Pl. X, fig. 11.) 
Hab. Barbadoes deposit, from Cambridge estate; C. 
Johnson, Esq., R. K. G. 
In this curious species the valve is so nearly circular that 
the first specimen which came under my observation 1 took 
to be a Coscinodiscus. The angles, in fact, project so very 
little beyond the circular line as to be hardly perceptible, 
and are only discovered by looking for them. The structure 
is cellulate, but at the first glance | seems coarsely granulate. 
Triceratium cinnamomeum, D. Ssp., Grev.— Valve of a 
reddish colour, with slightly concave sides and obtuse angles, 
minutely punctate; puncta forming a line which projects 
from each angle fully half way towards the centre, while 
along the margin they are arranged in arch-like series. 
Distance between the angles about 0030”. (Fig. 12.) 
Hab. Deposit at Moron, i in the province of Seville; G. 
Norman, Esq., C. Johnson, Esq., R. K. G. 
This little species, which is not rare in the Moron deposit, 
is characterised invariably by its reddish-brown colour, and 
by the line formed by two rows of puncta, which projects 
inwardly from the angles. There are, besides, not unfre- 
quently, three or four additional uncertain lines radiating 
very irregularly from near the centre. The latter, however, 
although evident enough in some examples, are scarcely per- 
ceptible in others. In the centre of the valve the puncta 
are not crowded, Towards the margin they are 18 in 001”, 
arranged in more or less arched lines, which, under a power 
of 400 diameters, form a remarkable and conspicuous cha- 
racter. 
Triceratium inflatum, n. sp., Grev.—Valve with very con- 
vex sides and somewhat obtuse angles, and several vein-like 
lines reaching from the margin about half way to the centre ; 
surface with remotely scattered puncta, which become 
smaller and more numerous at the margin. Distance between 
the angles ‘0035”. (Tig. 15.) 
