32 HELICID^. 



Shells, f. 50, from Drap. pi. 8, f. 30, 31 ) and part of the description (p. 65), but 

 subsequently (p. 142) referred his specimen to the young of Vitrina. His 

 drawing of V. elongata (Manual, f. 2*2) is likewise derived from the same source 

 (Drap. pi. 8, f. 41), the French species not being a native of this country. 



ZONITES. Gray. 



Shell spiral, more or less subdiscoicl ; spire of many 

 whorls, depressed, thin, polished ; mouth lunate, entire, 

 peristome thin ; columella perforate. 



Animal bulky, but not over-large in proportion to shell, 

 lanceolate ; head with four tentacles, the lower pair short; 

 mantle thickened and slightly reflected ; tail obliquely 

 truncated ; edge-teeth of tongue aculeate. 



We adopt this genus, in the sense given to it by Mr. 

 Gray, with a restriction, however, since we include in it 

 only the hyaline species of that author. It forms a 

 connecting link between Vitrina and Helix, but is more 

 nearly allied to the former than to the latter. This has 

 been proved by the observations of Mr. W. Thomson, on 

 the dentition of those snails, to which the name Zonites 

 has been applied. " From the very similar character of 

 the edge-teeth in Zonites alliarius, cellarius, nitidulus 

 and radiatulus (whose tongues greatly resemble each 

 other),'' 1 writes Mr. Thomson, " I am induced to believe 

 that they should come in between Vitrina and the true 

 Helices, for while their edge-teeth show no appearance of 

 bifurcation, the heel to the apex may possibly be looked 

 upon as an approach towards it. Their sagittate central 

 tubercle corresponds with that of Vitrina, and a similarly- 

 shaped central tubercle in Helix fulva connects them with 

 the true Helices, which have a simple aculeate tubercle. 

 Zonites radiatus (so called) is a true Helix.''''* 



* Annals Nat. Hist. 2nd ser. vol. vii. p. 01. 



