56 
Greville, on New Diatoms. 
verse lines, and that portion^ called a pseudo-nodule in the 
lateral view, forms in the front view a projecting process or 
short horn. Distance between the angles '001 6'". 
Triceratium trilineatum, n. sp., Grev. — Minute ; valve with 
nearly straight sides and subobtuse angles; structure com- 
posed of very minute radiating puncta, and a dark line ex- 
tending from the centre to the middle of the margin on each 
side ; within the raised angles a minute obscure pseudo- 
nodule. (Fig. 27.) 
Hab. Barbadoes deposit, Cambridge estate ; in slides com- 
municated by C. Johnson, Esq. 
Substance rather thin and delicate ; area of the valve some- 
what concave, the circular outline of the concavity leaving 
the angles a little raised. The three dark radiating lines 
seem to consist of a few closely approximating, slightly -ele- 
vated rows of cellules. 
DiCLADIA. 
Dicladia? Barbadensis, n. sp. — Large; valves conical, each 
produced into two elongated, robust, diverging horns. (Fig. 
28.) 
Hab, Barbadoes deposit, Cambridge estate; in slides com- 
municated by C. Johnson, Esq. 
In the extremely robust habit, and in both the valves being 
nearly equally developed into long horns, this diatom diflPers 
from the Dicladi(B generally. In the present example, it is 
true, one valve is more developed than the other, indicating 
perhaps an approach to the usual condition of the genus, 
where the processes of one of the valves are nearly or wholly 
abortive. But in another specimen the horns of each valve 
are nearly equal. Conspicuous puncta, or rather prominent 
granules, are scattered in groups on the valves and lower 
parts of the horns; but this, I apprehend, is an inconstant 
character. Breadth of the frustule '0020''; length, including 
both valves, -0060''. 
GONIOTHECIUM. 
Goniothecium prolongatuMj n. sp., Grev. — Valves narrow- 
oblong, extending at each end into a filiform continuation 
twice as long as the middle portions ; the latter conjoined by 
two minute processes. (Fig. 29.) 
Hab. Barbadoes deposit, Cambridge estate ; in slides com- 
municated by C. Johnson, Esq. 
Distinguished at a glance by the long, linear, filiform, 
truncate, and parallel terminations of the valves, which do not 
become in the least degree connivent. 
