6 MOLLUSCA. 
mantle has been aptly compared to one of those 
pincushions which are frequently made between 
pairs of these very shells, the eyes representing a 
double row of diamond-headed pins, set round the 
middle. It is observable that the Bivalves, which 
are thus profusely furnished with eyes, are also 
THE GREAT SCALLOP. 
endowed with the faculty of precise and vigorous 
motion. It does not appear clear that any of this 
Class possesses a distinct sense of hearing. 
The faculty of taste is plausibly conjectured, 
rather than proved, to belong to the MOLLUSCca. 
‘Jt seems necessary,” says Dr. Johnston, “to sup- 
pose the existence of this sense in all Mollusca, for 
they select particular articles of food in preference 
to others; and we know no other sense which is 
fitted to regulate the choice.” The organs appro- 
priated to this faculty are probably the margins 
and internal surface of the mouth, and the tentacles 
