82 
GrevillEj on New Diatoms. 
processes). If these remarkable differences are not consi- 
dered of value, I do not see how any character derived from 
the position of spines in any of the other species can be de- 
pended on. No approach towards an intermediate condition 
has been observed. It may also be remarked that the pro- 
cesses seem to be influenced by the position of the spines in 
B. Chinensis, for they are covered outwards, and are not 
straight, as figured by Smith and Roper in B. Mobiliensis. 
Biddulphia ? i^odagrosa, n. sp., Grev. — Frustules quad- 
rangular; valves with the angles prolonged into very thick 
processes, which are swollen and punctate near the base, 
then contracted, and again dilated into broadly capitate trun- 
cate, punctate apices ; median space, with a hemispherical or 
subcapitate elevation. Length of perfect frustule '0035'^ 
(Fig. 17.) 
Hah. Barbadoes deposit, Cambridge estate; in slides com- 
municated by C. Johnson, Esq. 
One of the extraordinary forms of the Biddulphia family 
only to be met with in the Barbadoes deposit. It is obviously 
allied to my Hemiaulus ? capitatus {' Trans. Mic. Soc,,^ vol. 
xiii, pi. 6, fig. 24), which would have been more appropriately 
registered as a doubtful Biddidphia. The present diatom has 
a most whimsical appearance. The horn-like processes seem 
as if they had become proliferous ; as if a second series had 
grown out of the first. The summits are large, inflated, 
almost cyathiform. The central projection is punctate like 
the processes, and in one specimen is so prolonged as to be 
almost capitate. The whole surface, with the exception of 
the punctate portions, is smooth and somewhat glassy. The 
processes are '0020^' in length. 
Triceratium. 
Triceratium lautum, n. sp., Grev. — Lai'ge; valve with 
straight sides, rounded angles, and large pseudo-nodules 
(processes) ; margin with a somewhat pectinate row of large 
cellules; granules rather remote, radiating from a central 
cluster, and increasing in size towards the margin. Distance 
between the angles '0050'^ (Fig. 20.) 
Hab. Barbadoes deposit, Cambridge estate; C. Johnson, 
Esq. 
This species bears a great general resemblance to T. pro- 
minens, but differs in the marginal cellules, in the angles 
being arched off and filled up .with much larger processes, 
and ill the al)sencc of any central inflation. 
