296 



those with the spire plain. To the above remarks and 

 description of the genus, may be added a few more 

 particulars tending to exhibit the peculiar characters 

 of this elegant shell; the aperture is terminated at the 

 upper part in a notch, occasioned by the suture or se- 

 paration of the external whorl from the spire. Be- 

 neath this appears a slight callosity, running round the 

 interior of the shell. The form of the shell is extremely 

 various: some being thin, cylindrical, and oval ; others 

 short and wide; some with a very produced spire, 

 which in other species is nearly flat and truncated, 

 either mucronated, coronated, tuberculated, or with 

 flattened or convex whorls ; the exterior more or less 

 covered with minute granulations, some quite smooth, 

 and others transversely grooved or sulcated. Many 

 species are known to be, and most probably all of 

 them are covered with an epidermis, which in some 

 species is very thick and has a tufted appearance, 



Adanson, whose veracity has never been impugned, 

 asserts that these shells are closed by an operculum, 

 and it is very extraordinary, that in a class of shells so 

 abundant, particularly in the hot latitudes, the animal 

 has never been examined by any other person, and 

 this assertion, therefore, has never been confirmed. 



