PLATE LXXXIV. 



$»ufficiently definitive to discriminate the two species from each 

 other. 



The shell, of which the figure is given in the annexed plate, is 

 the specimen once preserved in the Leverian Museum, and which 

 was sold by auction at the price of three guineas. This was nearly 

 twenty years ago, and the species having continued to be scarce from 

 that period, its value may be now considered greater. 



