80 GREVILLE, ON DIATOMACE. 
the Lamlash Bay gatherings, were two or three species of 
Cocconeis ; and I find that, in his correspondence with our 
mutual friend, Mr. Norman, of Hull, he referred to two of 
them under the provisional names of pinnata and crassa. 
Of the latter I have as yet discovered no trace; but, with 
regard to the former, although I have no certain clue to 
guide me, I think I may safely venture to assume that the 
form now described is the one so named by him. It is 
a beautiful little species, well distinguished by the short, 
strong, moniliform, distant strie, and by the narrow-elliptical 
blank space which longitudinally occupies the middle of the 
valve. I have the drawing of another apparently new and 
fine species, but the slide containimg it was returned, and I 
have been unable to find it. 
2. Cocconeis arraniensis, Grev. 
Valve oval; strize concentric with the extremities, slender, 
faint, moniliform, contiguous, reaching to the median line ; 
length :0016” ; strie 30 in ‘001”. (Fig. 2.) 
Marine. Dredged in Lamlash Bay, by Professor Balfour, 
1857. 
In working through some of Professor Gregory’s slides, 
this minute and inconspicuous form attracted my attention. 
It appears to be undescribed, and I do not know any 
species with which it is at all likely to be confounded. 
Under a moderate power of the microscope it is difficult to 
distinguish its structure satisfactorily. Compared with other 
species of the genus, the moniliform striz are slender and faint; 
and,in consequence ‘of their being g placed close together, the eye 
is caught as much by the sharp lines caused “by the juxta- 
position of the striz, as by the striz themselves; and it is 
not until a higher power is used that the structure is 
cleared up. 
3. Coscinodiscus Normanni, Greg. MSS. 
Areolation forming numerous fasciculi of radiating lines 
or rows of areole, each fasciculus composed of about six 
rows ; areolz equal, except at the margin, where they become 
suddenly smaller and faint; margin smooth; diameter of 
dise ‘0016” to -0036” ; areole about 24 in 001”. (Fig. 3.) 
Marine. In the stomach of Ascidians, Hull. George 
Norman, Esq. 
Professor Gregory’s attention was first directed to this 
Diatom by Mr. Norman, who obtained it, as well as many 
other interesting species, from the stomachs of Ascidians. 
Believing it to be new, he bestowed upon it the name of its 
