PLATE CLXXIV. 



OvaltSy Plate 89, of this work, a shell considered by Da Costa as 

 the true M. pictorum. The present species, which we have little 

 hesitation in believing to be the shell Linnaeus means, is more of an 

 oblong form than M, ovalis^ rounded at both extremities, thin, semi- 

 transparent, and of a pale colour, beneath the epidermis, which is of 

 a faint green, or brownish hue ; within the shell is pearly. 



The only synonyms we 'can venture to adopt with certainty, ar» 

 those above quoted. There can be no doubt that the figure given 

 by Chemnitz for the M. pictorum of the continental writers, is the 

 same as that now before us, but the extensive list of references to 

 other works, added by that writer, we are induced to reject as 

 being at least in many respects ambiguous. Our specimens of this 

 shell were obtained from Mr. George Humphrey, who assures us, 

 that although he never had met with it himself alive in this country, 



he was told some years ago by the late Seymour, Esq. that this 



very species had been fished up in the river Stour, 



