10 
Greville^ on New Diatoms. 
granules rather large, subquadrate^ the lines mostly continued 
simple to the margin. Diameter 'OOSC. (PI. fig. 2.) 
Hab. Barbadoes deposit, Cambridge estate; George 
Norman, Esq. 
It is to be hoped that this species will be found to retain 
its apparently strongly marked characters. I have repre- 
sented it as focussed for the depressed margin and processes. 
The furrows do not, as is most frequently the case, terminate 
in a suddenly expanded blank space surrounding the processes, 
but are simply rounded at the end, the processes themselves 
lying in the axils. The subquadrate granules (or cellules) 
are of much the same size throughout, and for about a third 
of the radius from the margin form close, undivided lines. 
The colour is rather dark. This must be an exceedingly 
rare diatom, as neither Mr. Johnson nor I, nor, T believe, 
Mr. Ealfs, have observed it in the innumerable slides we 
have examined. 
Aulacodiscus amcenus, n. sp., Grev. — Disc with numerous 
(6 or 7) sublinear, elongated, submarginal processes, and a 
circular umbilicus ; furrows definec} by a single row 
(on each side) of granules, and scarcely at all dilated at the 
extremities; granules large, subremote, the lines passing 
suddenly near the margin into a corresponding number of 
short, broad strise. Diameter •0047"' (fig. 3). 
Hab. Barbadoes deposit, Cambridge estate ; C. Johnson, 
Esq._, George Norman, Esq. 
A very beautiful and distinct species. The disc very 
convex, the convexity ceasing suddenly near the margin, and 
causing a narrow line of shade between the processes, the 
small space between this shaded line and the margin being 
flat. Granules subremote, each occupying the centre of 
large, delicate, hexagonal cellules, requiring careful adjust- 
ment to bring out clearly. In the example now before me 
the furrows between the centre of the disc and the processes 
are considerably wider than are the other lines from each 
other ; but in a specimen discovered by Mr. Norman this 
distinction almost entirely disappears, while the other 
characters remain the same. 
Aulacodiscus Grevilleanus , n. sp., Norman. — Very large. 
Disc with numerous (about 10) submarginal processes, and 
circular umbilicus ; compartments between the furrows 
covered with diagonal, intersecting rows of little cushion-like 
warts, rough with elongated and coral-like granules. 
Diameter -0110^ (PI. I, fig. 1.) 
Aulacodiscus Grevilleanus, Norm, in lift. 
