126 
On the Climate of the N. PF. Mountains'. 
[A?ril 
I had first occasion to observe this property in some specimens which I had 
gathered in August, 1828, and had put in a glass vessel with some tadpoles. 
One of these being transformed, and dying two days after, I found the Paludina 
f i tened on the carcase of the frog, and apparently feeding on it, as it shortly dis- 
appeared altogether : the other tadpole dying, was served in like manner ; as well 
as a small fish-like animal from the same pool. The landshell Helix ncmoralis, 
belonging to the phytiphagous family of the Colhnaceaf, has been observed feeding on 
dead animal substances : and thus far the anomaly in our shell is supported by a 
parallel example : but, as the following experiment will show, it proceeds still fur- 
tlier and devours living animals. 
On the 5th September, 1329, I caught a Paludina , and placed it in a tumbler of 
water. It soon crawled to the surface, and commenced swimming. I observed it 
with a lens, and found that the mouth was longitudinal, and that it was capable of 
being expanded to an oval shape, discovering inside, a bunch of prominent, hard, and 
parallel longitudinal plates, the edges of which were directed outwards : this hunch 
moved from the top to the lower part of the mouth with great quickness, thereby 
ci eating a slight current on the surface of the water, which conveyed the scum into 
its mouth, where it appeared to be swallowed. It appeared to make attempts to 
seize a minute living spider which bad fallen accidentally into the glass : the spider 
was, however, too nimble, and succeeded in mounting the foot of the Paludina, where 
it icmamed in security. The animal made various attempts to reach the spider 
witn its head, but without success ; and finally, the spider was forced to the end 
or the tail, by the action of the muscles, and was floated off. 1 brought the spider 
into the current, by blowing it a second and a third time ; but the efforts of the 
shell-fish were equally unsuccessful, and the spider escaped in the same manner as 
at first. I then procured a jumping mite, with long spider- like legs, which I floated 
on the water, and' blew into the vortex caused by the shell; on reaching it, the 
Paludina seized it, and dismembered it in a trice ; and in a very few seconds liad 
swallowed a great part of the animal, rejecting only one or two small fragments. 
1 he operation I observed under a lens. I intended to leave tried it again ■ but 
when I had leisure the weather had become too dry, and the jumping mites were no 
longer procurable. I have since fed Paladin, with musqtiitoe.s, newly killed, and 
floated on the surface of the water : these were soon attacked and carried to the 
bottom ; the body and soft parts being eaten, and the wings and legs rejected. 
Isinglass also proved a very attractive food. 
This little, and apparently insignificant shell-fish, thus appears to perform an 
useful part ,n the arena to which it is confined. Inhabiting, in general ? ZZZ 
pools and ponds, m which it sometimes absolutely swarms: it doubtless devours 
and assimilates the vast quantites of insects which are drowned in the waters fre- 
quented by it, and the bodies of such aquatic animals as are newlv dead • there- 
in ? 1 ^ l } ulins l . he ^“brity of the surrounding air, and fordid upon’ us the 
truth of the conclusion so continually recurring to the enquirer in natural science 
that nothing was made in vain.” The total extinction of the race in diXs and 
pods, hade f° occasional drought, and therefore the more in want of purifying 
agents, is effectually and admirably guarded against bv its mnnKJiw e ^ a ’ ■ » 
pr^ion of water and food. a., exhibited in ' 
Bundclklmnd, February 9 tk, 1830. experiments^ ^ 
Sir, 
IV.— 0« the Climate of the North-Western Mountains. 
To the Editor of Gleanings in Science. 
ed 
iar tables in future, for publication. 1 ‘-asuie m transmitting to you slim- 
every^esp^t as^fficielit as any^in^Indfa^* thd Accuracy JT des . cripti ° n ' * 
accuracy or my observations may, 
c/ &£$ «• **• m-e ^ 
