6 
GrevillEj on New Diatoms. 
Hab. Barbadoes deposit, Cambridge estate ; C. Johnson, 
Esq. ; extremely rare. 
In outline, but in no other character, resembling A. ovalis. 
The radiating lines which form the cross,, are simple as they 
leave the centre, but afterwards, by giving off two or three 
very short ramuli, terminate within the margin in pencils of 
rays. An intermediate pencil on each side is obscure, but 
probably might be more decided in other examples. Long 
diameter -0025'^ 
BlDDULPHIA. 
BiddulpMa fimbriata, n. sp., Grev. — Structure minutely 
dotted ; valves with the angles produced into curved, obtuse 
horns, and furnished with a marginal row of long filaments. 
{Pig. 4.) 
Hab. Barbadoes deposit, Cambridge estate ; in slides 
communicated by C. Johnson, Esq. ; rare. 
A most extraordinary species, of which I have seen at least 
half a dozen examples in different degrees of preservation. 
The horns are slightly tumid towards the base, and the ter- 
minal articulating surfaces obliquely truncate. The most 
remarkable feature consists in the filaments which fringe the 
discoid margin of the valve. None of them appear to be 
quite perfect at the apex, and yet in the specimen figured they 
are as long again as the horns. Minute raised points are 
sparingly scattered towards the margin of the valve. Diameter 
•0035". 
BiddulpMa spinosa, n. sp., Grev. — Structure very minutely 
punctate; valve elliptical, produced at the angles into 2 
minute horns, and armed with 3 marginal spines on each side, 
besides 1 opposite each horn. (Eig. 3.) 
Hab, Barbadoes deposit, Cambridge estate ; in slides 
communicated by C. Johnson, Esq. ; rare. 
Although this diatom is decidedly rare, I cannot have seen 
fewer than a dozen or more specimens of the valve, all re- 
taining its well-marked characters ; the only variation being 
some difference in the breadth, and in the acuteness of the ends. 
The horns are very small, obtuse, and without any inflation 
at the base. Diameter about •0030"". 
Triceratium. 
Triceratium Dobreeanum, n. sp., Norman in lit. — Large; 
valve with straight sides and obtuse angles produced into 
