gular convexity ot the whorls, not m any degree coinprebsed at 

 the suture, the want of that thickened appearance on the spire, 

 and of the contraction at the base of the mouth (all which cha- 

 racters I have found in the varieties of B. citriiius to be con- 

 stant), afford a specific distinction which future observations 

 must confirm or annul. Bruguiere notices a variety of B citrinus 

 which is entirely yellow, a most beautiful specimen of which is 

 in the British Museum, and which possesses (as well as the ex- 

 cellent figure of Gualtieri) all the specific characters I have given 

 to B. citrinus, but not of the present shell. Lister's figure, on the 

 contrary, is rude, though very characteristic of this ; and Mar- 

 tini's representation, here cited, also appears the same. 



Mr. Dubois, in whose collection this specimen exists, is un- 

 acquainted with its locality. 



