Greville, on New Diatoms. 
depressed,, with a broadly expanded hyaline margin ; areola- 
tion large ; connecting processes robust^ spine-like, situated 
nearer to the margin than the apex. Diameter "0024" to 
•0354". (PI. VIII, figs. 3, 4, 5.) 
Hab. Barbadoes deposit ; frequent. 
A splendid species, with very large areolation. Average 
specimens possess from six to eight connecting processes, but 
examples occur with from four or five, up to the pant repre- 
sented at fig. 5, with nineteen. I have never seen Ehrenberg's 
Stephanopyxis diadema ; but if Kutzing^s definition be 
correct, disci medii depressi annulo dense denticulato" — my 
present diatom must be distinct. Kutzing, besides, gives the 
number of teeth in the crown as thirty, whereas it is a very 
rare circumstance indeed to see so many in Cresswellia su- 
per ba as appear in fig. 5. 
EUODIA. 
Euodia Barbadensis, n. sp., Grev. — Frustules semilunate, 
ends slightly produced, lower margin straight ; surface cellu- 
lose, with a small, irregular, central blank space. Distance 
between the angles -0015" to -0020". (Figs 6, 7.) 
Hab. Barbadoes deposit ; extremely rare. 
V alve yellowish ; short, vein-like lines are given off from 
the margin, sufiiciently conspicuous in the larger specimens, 
but less so in small ones. The upper margin is conical-con- 
vex, so as to give the frustule very much the outline of a 
cocked hat. Cellulation rather large, but under a low power 
appearing as granules. 
Triceratium. 
Triceratium cornutum, n. sp., Grev. — Valve (4-angled?) 
with straight sides and sharp angles furnished with strong, 
horn-like processes ; surface minutely granulose, in lines ra- 
diating from the centre, on which are three spines ; granules 
at the margin 15 in -001". Distance between the angles 
•0015". (Fig. 8.) 
Hab. Barbadoes deposit ; excessively rare. 
The only frustule, a very perfect one, which has come under 
my notice, has four angles Avith exceedingly strong, horn- 
like processes, which, as they cast a dark shadow, render the 
frustule conspicuous. The granules are very minute in the 
centre, but increase in size as they radiate to the margin. It 
is quite distinct from the few species already described, having 
spinous lateral surfaces. 
Triceratium productum, n. sp., Grev. — Valve punctate ; 
