BARNACLE. 
549 
muscles, and lobsters ; and absolutely encrusts many 
of the small rocks with which our coasts abound. 
The shell is of a conical shape, and when perfect is 
covered by a little lid, which the animal within oc- 
casionally raises up in order to admit the sea-water, 
and collect such food as is congenial to its nature. 
The shell, like the limpet, is open at bottom, by 
which part it adheres to the rock, and that with such 
firmness, that we have frequently found it difficult 
to separate it even with a knife. 
The animals inhabiting these shells are of very sin- 
gular formation, having twenty-four small tentacula 
or feelers, which are like so many feathers, and'with 
which they secure the smaller marine insects that 
serve them for food. Whenever the little animals 
feel inclined to search for prey, they lift the oper- 
culum which covers the shell, and stretch forth 
their tentacula, which remain fully extended till 
something of sufficient importance comes in their 
way; when the barnacle immediately secures the 
prize, and, sinking into its shell, devours the 
booty at leisure. Mr. Ellis, who has given a par- 
ticular account of these creatures in the Philoso- 
phical Transactions, has described the tentacula as 
differing in size, the twelve smallest being placed 
six on each side of the others; he thinks they per- 
form the office of hands, being more pliable and 
hairy than the larger ones. They have a trunk or 
proboscis rising from the middle of the base of the 
larger claws, and longer than any of them. The 
animal is able to move this trunk in any direction : 
