on the Chitonide. 33 
top, is to be filled with fresh water to overflowing, and the animals 
thrown into it: they are to be covered over with flat even glass, and in 
this prison-house they are suffocated and destroyed, the organs remaining 
extended in their natural attitudes. It is better to use separate glasses, 
as the animals,* if placed together, by crawling over each other, often 
in fright retract their organs; and they are to be kept as still as possible. 
When quite dead, they are to be thrown, without loss of time, into 
weak, and afterwards stronger spirit: some are to be preserved naked, 
while the shells of others may be retained, the spire being perforated or 
cracked, for the admission of the antiseptic fluid to the spiral turns of the 
abdomen. It does not, however, so well answer for the Ampullariade, 
and those genera which possess branchiz as well as a respiratory cavity 
(Respiratorium.) On these it would be advisable to try the shock of an 
electric battery. Veritine are destroyed with great difficulty: some 
which were even kept close in salt water seemed to have the power of 
purifying it, and rendering it fit for respiration, while many large air- 
bubbles were generated in the glass. Some power of this kind would 
be very valuable to those species which inhabit maritime ponds, the wa- 
ters of which, nearly dried up at certain seasons, must be stagnant and 
unwholesome. 
The marine univalves, if kept still in separate vessels thus covered, 
will die in their natural attitudes, though not without some exceptions, 
which the zoologist will be taught by experience. All, however, are 
liable to deceive the operator. Although lying reversed, and apparently 
lifeless, many, when thrown into spirit, will possess sufficient muscular 
power to withdraw within the shell, when suddenly stimulated by the 
ardent spirit. It would be safer to pour off gently the stale sea-water, 
and to have bviling water dashed on them, to secure the success of the 
operation. 
Many of the minuter shells, as soon as the animal has been described, 
are to be thrown into spirit, and the operculum in situ may be observed 
* In warm countries, if the smaller Land Mollusca are captured at a distance 
from home, they should be placed in tin boxes, with only damp leaves, and 
all water carefully poured out: without this precaution, the steam generated 
during the night will be fatal to the captives, 
Vou. V. c 
