MOLLUSCA. 233 
cessary to the successful prosecution of the science of con- 
chology. To accomplish this, much care and attention are 
requisite. Shells must be sought for in their natural situa- 
tions, and obtained, if possible, with the animal alive. After 
the animal has remained dead in the shell for any length of 
time, it loses its lustre and transparency, and becomes less 
valuable, either as an object of beauty or curiosity. Hence 
the collector must explore the sea-coast, the land, and the 
fresh water, in search of the testaceous animals which they 
support, for the purpose of obtaining in a perfect state their 
calcareous coverings. 
The sea contains more species of shells than either the 
land or the fresh waters, and presents to the concholegist an 
extensive field for observation. Many species of marine 
shells frequent the sea-shore, adhere to rocks, stones, or sea 
weed, or lodge in the clay or sand. These are termed Lzt- 
toral shells, and are seldom found in deep water. The lit- 
toral shells are easily collected at ebb tide. Those which 
burrow in the mud or sand may be detected by a small de- 
pression which they leave on the surface as they retire below 
it. Other shells live in deeper water. To collect these the 
dredge must be employed; and if the shells be put into sea 
water after they are brought up, the animals may afterwards 
be examined with ease. Such collectors as have not the 
advantage of a dredge, should examine the refuse of fishing 
boats, and traverse the sea shore, and search the rejecta- 
menta, especially after a storm of wind. The roots of the 
larger Fuci, especially F. digitatus, which grows sometimes 
in four or five fathoms water, frequently contain a treasure 
of the rarer shells. 
During the ebb of stream tides, the conchologist ought 
to be very diligent. T he rocks are then uncovered, and 
