ZONITES. 89 



the name Vitrina margaritacea, t. 40. f. 54, 55, 56., 

 a shell which I have not been able to see; the figure 

 is more like a Zonites than a Vitrina. 



The animal is very hardy ; for, according to Nil- 

 son, it is found crawling about amongst leaves in the 

 southern part of Sweden in the depth of the winter, 

 and it is also found in the most northern part of that 

 country. 



** Mantle not produced in front, simply lining the 

 cavity of the shell, with a thicker edge or collar 

 enclosed within the edge of the shell, in which is 

 placed the respiratory cavity. 



f Body and mouth of the shell depressed, being 

 broader from side to side than long from front 

 to back, that is to say in the direction of the axis 

 of the spiral shell. (Helicina.) 



3. ZONITES Montf. (Zonites.) 



Animal with an elongate depressed foot, and a large 

 produced central spiral body, covered with (and 

 contractile into) a depressed or hemispherical, 

 thin, smooth, polished shell, with flattish spire, 

 and a large lunate mouth, with thin simple lips, 

 which are neither thickened nor reflexed ; the 

 tentacles are four, the two lower ones small and 

 club-shaped; tongue narrow, with from 30 to 

 60 longitudinal series of teeth, with elongated 

 apices. 



The tongue of Zonites alliarius, cellarius, niti- 

 dulus, and radiatulus greatly resemble each other, 

 and are somewhat intermediate between Vitrina and 



