16 THE HALL OF SHELLS. 
have been strung of them, and such are found 
in some of the most ancient sepulchers. 
“When you are well enough to go down 
to the beach you will wonder at the power 
of adhesion possessed by these little limpets, 
for it is impossible to remove them from the 
rocks without breaking their shells unless they 
are surprised by sudden seizure. 
“Some authorities say this is owing to the 
large round foot of the Patella, hie is very 
muscular and possessed of a viscous secretion 
which aids it as a sucker. The perfectly even 
edge of the shell keeps it tight agaist the 
rock, while ‘the power of treating a vacuum’ 
a problem too old for your young head— 
is said also to enter imto the operation. 
Others attribute the adhesion to no.muscular 
action, but chiefly to the ‘invisible glue which 
exudes from the granulated base of the sole of 
its foot,’ as the expansion upon which the ani- 
mal moves is called. We find upon removing 
one.of these little creatures from the rocks 
that a sticky secretion is left where the limpet 
clung. This gluelike substance is soon dis- 
solved by the action of the sea water. 
“A weight of from twenty-eight to thirty 
pounds has ‘been suspended from the shell of a 
limpet attached to a stone; the weight was 

