400 
both these localities C. elliptica also occurred ; indeed, the 
latter and C. solea are found in most fresh-water gatherings, 
both being exceedingly common. If these observations, 
th/»n, are correct, C. apiculata and C. Hibernica of Professor 
Smith must be struck from the category of species. 
I would here venture to suggest to those who are investi- 
gating the diatomaceae, the importance of studying them in 
their natural habits, and of obtaining them there for exami- 
nation in the living condition. The mud of tidal estuaries 
should, as much as possible, be avoided, it being the receptacle 
for all kinds of species — fresh water washed down from the 
mountains, as well as marine washed up from the sea. The 
leaves of aquatic plants, especially if filiform, like the Blad- 
derwort and Water Ranunculus in clear still water, should 
always be subjected to a microscopical examination on the 
spot, if possible ; if not, portions should be brought home in 
bottles filled with water. The attachment of many of the 
adherent species, such as Epithemia gibba, is exceedingly 
brittle; great care, therefore, should be exercised in drawing 
the plants to which they adhere from the water. The force 
of a strong wind on water not too deep will detach and 
scatter them floating about as free individuals — a circumstance 
which has caused the real character of many species to be 
overlooked. 
From the pond at Wallington I obtained a large supply of 
adherent species by getting into a boat and providing myself 
with a large wide-mouthed pickle bottle, which I filled with 
water and placed on one of the seats. I then carefully cut 
off a stem of the bladderwort, drew it gently from the water, 
and holding it by its lower extremity dropped it into the 
bottle, in which it was roughly twisted about and gently 
pressed between the fingers in withdrawing it from the 
bottle again. By treating a succession of stems in the same 
manner the water soon became quite thick and brown look- 
ing from the immense quantity of Diatomes collected ; the 
surplus water was easily got rid of by allowing the bottle 
to stand for awhile ; the Diatomes soon settled down to the 
bottom, and allowed the water to be poui’ed off. The collector 
will find this a much more satisfactory method of gathering 
than by poking amongst aquatic weeds with a small bottle 
attached to the end of a stick. 
