62 BIVALVES. — OSTREA. 



There is also considerable variation in the size and form 

 of the ears, which in some species are nearly of the same 

 dimensions; but, in many, one is much larger than the 

 other ; and in a few, they are hardly discernible. 



The ears of many of the scallops are almost smooth on 

 the outside, but some are rough, and even spined. The 

 O. pallium and others have one ear ciliate, and are spin- 

 ed within. 



The exterior of the shells, as has been before observed, 

 is usually covered with elevated longitudinal ribs and 

 grooves, which are variously diversified with beautiful co- 

 lours and fine chequer-work. The ribs are mostly covered 

 with undvilated and transverse strise, not unfrequently as- 

 suming the appearance of elevated scales, as in the O. im- 

 bricata. In others, again, the striag are crenated, as in the 

 O. radula; and some, as the O. nodosa, &c. have large 

 knobs or tubercles raised upon the ribs. 



The margins of the interior of the Ostre^e are generally 

 crenated, and often beautifully coloured. 



The hinge is universally without teeth, and furnished 

 with an ovate hollow ; in the vicinity of which are placed 

 lateral transverse grooves, running in a parallel direction 

 in both valves, but not locking into each other, as in the 

 genus Area. 



The common scallop, O. maxima, is found in most Eu- 

 ropean seas, in large beds, from which they are dredged by 

 the fishermen, and afterwards pickled and barrelled for 

 sale ; they are also sometimes brought to market in the state 

 in which they are caught, and are eaten fresh. These 

 shells were formerly worn by pilgrims on their hat or coat, 

 as a mark of their having crossed the sea for the purpose 

 of paying their devotions at the holy shrine, in Palestine: 

 in commemoration of which, they are still preserved in the 

 armorial bearings of many families of distinction. 



The scallops are found harbouring among fuci and zo- 



