CARYCHIID^. 103 



Family III. CAEYCHriD^. 



(See Vol. I. p. 299.) 



In the upper part of the shell the internal convolutions 

 of the spire are wanting, although sometimes repre- 

 sented by slight ledges or the remains of the septa. 

 This may be seen in the typical genus Carychium as 

 well as in Melampus. The division of the penultimate 

 from the last whorl is complete, however, in every state 

 of growth. The only way in which I can account for 

 the disappearance of the septa, which must therefore 

 have been originally formed in each of the upper whorls 

 in succession, is that the mantle in that part has an 

 absorbent power. If the agent were an acid, the lining 

 or inner coat of the shell would be affected ; and such 

 is not the case. Carychium (Vol. I. p. 300) is the first 

 named genus of this family. 



Genus II. MELAM'PUS^ De Montfort. PL IV. f. 2. 



Body enclosed in a spiral shell : mantle thickened at its 

 outer edge : head furnished with an extensile snout : tentacles 

 club-shaped, contractile : ei/es sessile, on the inner side of the 

 tentacles, at their base : foot elongated : resjpiratory orifice and 

 air-pouch on the right-hand side. 



Shell oval or spindle-shaped: epidermis thin, sometimes 

 raised so as to form a row of short bristles on each side of 

 the upper whorls : spire conical, incomplete : mouth oblong, 

 narrow: outer lip more or less thickened within, mostly 

 toothed or fluted: 'pillar furnished with folds, two or three 

 of which are stronger and always present ; there is no umbi- 

 Hcus, nor operculum. 



This genus has been much, and in my opinion unne- 

 cessarily, subdivided; and the only two species living 



* A classical name. 



