PURPURA. 383 



body is more or less ventrieose above, aud is gradually and 

 convexly attenuated in front to a rather sharp peak. A 

 rather narrow nearly straight and perpendicular canal, 

 which occupies from scarcely two-fifths to nearly half of 

 the orifice, terminates the aperture of adult examj^les, 

 which in that stage of growth is small and suboval, being 

 much contracted in its dimensions by the breadth of the 

 outer lip. The mouth, and more especially the throat, 

 exhibits many diversities of colouring ; if not white, it is 

 usually stained with yellow, pink, flesh, purplish, or brown, 

 but these tints are rarely vivid (the first excepted) but 

 have usually a somewhat livid cast ; the darker the ex- 

 terior, the more intense in general will be the internal hue, 

 and when bands adorn the outer surface, they are usually 

 limned on the interior likewise. The only sculpture 

 which the aperture displays consists of five or six small and 

 rather distant tubercles (the first of which rises at some 

 little distance from the posterior extremity) that guard 

 the entrance of the throat, at the point where the very 

 thick outer lip, which is moderate in curvation and pro- 

 jection, begins to bevel gradually to a tolerably sharp 

 edge. In immature individuals, however, the outer lip is 

 simply acute, and merely displays the external folds at its 

 margin, instead of being tuberculated internally ; the aper- 

 ture, too, is much larger, and the canal not being com- 

 pleted, somewhat pyriformly oval. The inner lip is 

 smooth, appressly or even retusely flattened, and broadly 

 repand ; its edge almost vies in concavity with the opposite 

 margin. The average length of adult specimens is only 

 an inch and a quarter ; they sometimes, however, attain 

 to fully half an inch more ; the breadth is rarely above an 

 inch. 



The animal is entirely yellowish white or cream-coloured. 



