Page:Natural History, Mollusca.djvu/18

 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. "It seems necessary," says Dr. Johnston, "to suppose 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 appropriated to this faculty are probably the margins and internal surface of the mouth, and the tentacles