Greville_, on New Diatoms. 
73 
There is also something very unusual in the situation of the 
processes^ They are not placed at the termination of the 
ridge-like folds which separate the compartments where we 
should naturally look for them, but in the middle of each 
compartment^ next the margin; an arrangement which re- 
minds us rather of the spine in Omphalopelta. Again^ there 
is no true connecting furrow. The usual law is a linear 
channel,, bounded on each side by a row of granules ; or if 
the channel or furrow be nearly obsolete, still the radiating 
lines of granules run parallel with the obsolete furrow. There 
is nothing like this in A. ? paradoxus. The lines of granules^ 
which are beautifully arranged quincunx fashion, come down 
obliquely from the ridge on each side, to meet in the middle 
at an acute angle ; and as the meeting of the two opposite 
sets of lines is not exact, the end of one line often overlaps 
the ends of another, and produces an irregularity which 
attracts the eye, since it constitutes an obscure sort of line, 
bearing, however, no resemblance to a furrow. The processes 
themselves do not resemble those of the genus, being, as far 
as I can make them out, mere oblong or linear-oblong 
tubercles, in the middle of an elliptical blank space, and not 
presenting the usual dilated base. In the centre of the valve 
is a rather large umbilical space. This diatom will probably 
form a distinct genus. 
EUPODISCUS, 
Eupodiscus puncfulatus, n. sp., Grev. — Pale; disc slightly 
convex, minutely and somewhat concentrically punctate; 
puncta smaller in the centre, then becoming equal through- 
out; processes (4) marginal. Diameter -0032". (Fig. 19.) 
Hah. Barbadoes deposit^ from Cambridge estate; C. John- 
son, Esq. 
Clearly characterised by its minute^ uniform punctatiou, 
arranged somewhat in the manner of an engine-turned 
pattern, there being no radiation in any part of the disc. 
The four processes are rather small, circular, close to the 
margin, and prominent when seen in profile. 
Eupodiscus simplex, n. sp., Grev. — Disc slightly convex, 
filled up with small, uniform, hexagonal cellules ; processes 
(2) large, circular, or broadly oval, at some distance from 
the margin, within which is a row of very minute puncta. 
Diameter about -0030". (Fig. 20.) 
Hab, Barbadoes deposit, from Cambridge estate ; C. John- 
son, Esq. 
A most beautiful species, easily known by its regular net- 
work of hexagonal cellules, which are about 7 in -001". I 
