92 CON us. 



The shells of this genus are usually covered with 

 an epidermis, and under it, when in good preser- 

 vation, bear the most brilliant polish. This fine 

 surface contributes much to heighten the delicate 

 and glowing tints which are diffused over some of 

 the finer species in an infinite variety of undula- 

 tions, clouds, spots, bands, and reticulated figures. 



In enumerating the divisions of this genus, as they 

 stand in Gmelin's edition of Linnaeus's Systema, 

 the comparative length of the spire, with that of 

 the body, has been suppressed ; because no two 

 species answer exactly to the same measurement, 

 and even in the same species the proportion will 

 be found to differ. The character, therefore, can 

 only create confusion. The division D contains 

 but one species, C. Sinensis^ which is not figured, 

 because the author has not been able to procure an 

 inspection of the shell itself; and he is unwilling 

 to deviate from his purpose, of offering none but 

 original drawings. The Greek jcwvoj expresses the 

 peculiar form to which the genus is indebted foe 

 its name. 



