Greville, on Neiv Diatoms. 
43 
Hab. Barbadoes deposit; rare. 
A very delicate^ transparent little disc, easily overlooked, 
but well marked by its wide fringe-like rays. 
Coscinodiscus Barhadensis, n. sp., G-rev. — Disc divided into 
compartments by double lines of punctiform cellules, the 
intervals between the lines being so clearly defined as to pre- 
sent the appearance of rays; cellules within the compart- 
ments less conspicuously radiate, subequal, except at the 
margin; 15 in '001'' ; diameter of disc •0025". (Fig. 9.) 
Hab. Barbadoes deposit ; very rare. 
Disc convex, very delicate, and apt to be overlooked even 
by careful observers. Under a moderately magnifying power 
it would scarcely be taken for a Coscinodiscus , as it rather 
suggests the idea of an Actinocyclus (Ehrenberg, not Smith) ; 
but, under a higher power, the apparent rays are found to re- 
sult from the space left between two lines of cellules, which 
radiate from the centre to the circumference. Further ob- 
servations may determine the presence of an umbilical pore. 
One of my specimens is injured at that part ; and the other 
shows, although obscurely, an approach to such a character. 
Triceratium. 
Triceratium capitatum, n. sp., Ralfs. — Valve with the 
angles much produced and capitate, and separated from the 
centre by a transverse line ; surface with indistinct, scattered 
puncta, and two spines. Distance between the angles about 
•0019". (Fig. 10.) 
Hab. Barbadoes deposit; extremely rare. 
" A small species, with very indistinct puncta. Valves, 
irrespective of the produced angles, straight or slightly con- 
vex." (Balfs.) The frustule appears to be not unfrequently 
imperfect or mutilated. I had examined half a dozen ex- 
amples before I perceived any trace of puncta at all. Mr. 
Rylands then kindly communicated a specimen, in which, in 
addition to the central puncta, a few larger and more definite 
puncta were scattered on the narrow portion of the produced 
angles, and the surface was also furnished with two conspi- 
cuous spines. I have subsequently found two frustules 
myself, exhibiting very distinctly these characters. 
Triceratium Westianum, n. sp., Grev. — Sides of the valve 
deeply and sharply concave ; angles forming segments of 
circles, separated from the centre by transverse lines ; margin 
of the angles with very short radiating lines ; surface strongly 
punctate; distance between the angles •OOlS." (Fig. 11.) 
Hab. Barbadoes deposit; extremely rare. 
