1830.] 
On q, Species of Paludina. 
125 
JU. Further Remarks on the Property of enduring Drought , and the 
carnivorous Propensities of a Species oj Paludina. 
In the 363rd and following pages of the 1st vol. of the Gleanings, I related 
some facts connected with the power of enduring drought, possessed by a small 
snecies of Paludina *, and ventured several suppositions to account tor tue ap- 
pearances observed. I have now the pleasure to offer subsequent observations, 
continued through several months, illustrating the subject, and if not absolutely 
confirming, at least strongly supporting one of my conjectures. I shall relate my 
experiments in the order in which they occurred. . 
On the 17th September, 1829, I observed, that out of seven Pa ludince Poured 
from the pool formerlv mentioned, and left in a tumbler of water, one had fixed it- 
self to the side of the glass by the outer surface of the operculum, which was per- 
fectly closed : in which situation it was left dry by the evaporation and fall of 
the water. The animal having, apparently, selected this situation of its own ac- 
cord, I thought it a good opportunity of trying whether it would out1 ' v e the ex- 
posure for a short time; and accordingly poured off the remainder of the water 
leaving the shell adhering to the glass in the situation which it had chosen. On 
the 24th September I poured water into the tumbler untd the shell was immersed, 
and, on examining it three hours after, had the pleasure to find the animal alive 
and vigorous, ami crawling about the tumbler. During the interval, the weather 
was perfectly dry, and on the last day, the wind was quite hot, in consequence of the 
unusual drought. . , , , 
On the 4th October I took four of the specimens above mentioned, and place l 
them in a glass vessel, covering them to the depth of one inch with earth which 1 
wetted to make it adhere firmly. The vessel was nailed up in a small box and 
was carried on a hackery, exposed to the sun, to a distance of 40 miles, when it 
was placed in a godown and neglected for some days. On the 1st November I took 
up all tbe specimens and found the earth so dry that it was capable of beang re- 
duced to powder between the fingers. No rain had fallen in the interval. I placed 
two of the shells in a tumbler of water, and enclosed tbe other two m earth as be- 
fore. In the course of twenty-five minutes I bad tbe satisfaction of finding one of 
the Paludina: crawling about in the water, as if nothing unusual had occurred, and 
shortly after the other followed its example. This I considered almost an expert- 
mentum crucis y but resolved on still further trying the powers of the remaining 
^On^heDth January, 1830, three months and a half having elapsed since the 
two remaining shells had been deprived of water, I immersed them in their native 
dement one shell immediately rose to the surface, the animal having died, and 
having been completely desiccated and withdrawn into the apex of the shell : but 
the other shell appealing to be still filled by the animal, I continued to keep it 
separate in water, although with faint hopes of seeing it revive. owever, as i 
former companions, which had been kept in water since their release, . were then 
tovnid Drobablv in consequence of the coldness of the weather, I thought a chance 
was 'lef and H changed° the w'ater at intervals. On the 3rd February the weather hav- 
ing become warm, in consequence of the continued drought since August, I was 
surprized, a few minutes after renewing the water, to observe the httle Paludina 
moving about, after a torpidity of four months, during three and a half of which it 
had been destitute of water, so indispensable to most aquatic shells. The same 
heat caused its two former companions to move about in their vessel of water. 
These experiments strongly support the probability of my first supposition being 
correct- viz. that the animal, in its perfect state, has the property of retaining 
within itself sufficient moisture to sustain vitality in the cky, ™Aer 'the ^ s 
pool, until the return of rain ; but to place the matter beyond idl doubt, it will be 
iipoessarv to institute fresh experiments during the three months ot the hot winds, 
and to place in the earth, at various depths, in places exposed to the sun 
ai My° remaining observations relate to an unusual, although not ahogetheranun- 
known occurence; viz. that of a shell, belonging to a family esteemed phjl ^ 
gous, possessing a zoophagous propensity. This habit occurs m the same animal 
upon which the foregoing experiments were made. 
i This shell I described, without a name, in yol. i . page 36: 3 1. As < oth< 
is known to possess a calcareous operculum, it is doubtless . ne sp , 
fore call it P. Cerameopoma, from K epaptos testaceus, and Ilwaa operculum. 
