252 BARKAS, ON BACILLARIA CURSORIA. 
ness, and thus am able to confirm the truth of Mr. Wenham’s 
observation with respect to the hexagonal form of the cells 
which clothe the internal surface of the valve. This success 
has emboldened me to undertake the work, and afforded me 
an opportunity of presenting you with a specimen of it in a 
few photographic figures of various diatoms, which I think 
may suffice to prove the utility of photography in microscopic 
researches, whilst I believe it may be asserted that the pho- 
tographic reproduction will have the advantage, not only of 
being an authentic representation of the form of the objects 
observed, but of faithfully reproducing, at least, as much as 
we have succeeded in discovering by the eye applied to the 
microscope. 
This is as much as I have hitherto been able to effect, and 
a sketch of what I propose to do in the future, if my courage 
is sustained by your kind co-operation and that of those who 
may be generously disposed to assist me. 
Nores on BactLLaRiA CURSORIA. 
By T. P. Barxas, Esq. 
Ir may not be uninteresting to some of your readers to 
know that B. cursoria is to be had in great abundance and 
very frequently on the Northumberland coast. Within the 
last few years I have made scores of gatherings from the 
sea-beach and rock-pools extending from the mouth of the 
Tyne to Cullercoats, a distance of about one and a half 
mile, and at least one half of those gatherings contained the 
curious frustules of B. cursoria. There is a large pool at the 
mouth of the river Tyne which is left shallowly filled with 
water at every tide, and is situate near the high-tide mark, 
from which pool I have obtained frequent gatherings of 
Diatomacez, and it is remarkable to observe how the leading 
species on each occasion continue to change. In a gathering 
made on the 18th April I found several Actinoptychus, 
varieties of Coscinodiscus, &c.; and on the 8th May last I 
obtained almost pure, and in great abundance, Nav. pseudo- 
libellus, n. sp., discovered by Mr. Atthey, and described by 
Mr. T. West in the ‘Trans. of the Tyneside Naturalists’ 
Field Club,’ vol. iv, p. 321. On the 16th of May I took 
another gathering from the same pool, and found it consisted, 
for the most part, of varieties of Pleurosigma, with only an 
