Greville^ on New Diatoms. 
73 
Cocconeis granulifera, n. sp., Grev. — Minute^ elliptic- 
oblong, with a median line and rather large nodule ; disc 
with remote radiating lines of large, oval granules (three in 
each line), reaching from the median line to the niargin. 
Radiating lines 5 in -001". Length -0015". (PL VIII, fig. 19.) 
Hab. On Pectens, Carrickfergus ; John Grant, Esq. 
The characteristic features of this little species are the very 
large granules, the small size of the valve being considered 
(three only being found in each line), and the distance 
between the radiating lines themselves, there being only 
about thirteen on each side. Both this and the preceding 
appear to be clearly distinct from all described species. 
Descriptions of New and Rare Diatoms. Series III. 
By R. K. Greville, LL D., F.R.S.E., &c. 
(Read June 12tb, 1861.) 
Brightwellia, Ralfs. 
Brightwellia elaborata, n. sp., Grev. — Cellules of coronal 
circle roundish ; border composed of uniform, radiating lines, 
connected by numerous transverse lines. Diameter -0034". 
(PI. IX, fig. 1.) 
Hab. Barbadoes deposit ; excessively rare. 
This exquisite diatom bears a considerable general resem- 
blance to Brightwellia Johnsoni of Ralfs, MS., being of the 
same size and having a very similar coronal circle of large 
cells. But an essential difference is found in the structure 
of the border. In B, Johnsoni it is composed of radiating 
lines of round cellules, which decrease in size from the corona 
to the margin, where they are quite minute; while at irregular 
intervals dark, strong, radiating lines occur, which appear to 
project like a spinous ridge, as in my Coscinodiscus armatus. 
In the present species, on the contrary, the border is formed 
by a close series of straight, uniform, radiating lines, connected 
by transverse (or concentric) lines or bars, which thus pro- 
duce rows of quadrate cellules, increasing in size from the co- 
ronal circle to the margin. Two of the radiating lines, with 
their connecting bars, might not unaptly be compared to a 
microscopic ladder. 
