168 HELiCIDiE. 



Z. alliarius. This species is one of our upper tertiary 

 fossils. Its foreign range extends from the North of 

 Russia to Corsica and Algeria, through all the inter- 

 mediate countries. 



Nothing appears to be known as to the habits of this 

 snail, except that it is, like its congeners, of an inactive 

 or sluggish nature and that it forms a slight epiphragm 

 during the heat of summer. 



The shell differs from that of Z. radiatulus (which it 

 somewhat resembles) in its much larger size, more pro- 

 minent spire, the last whorl not being so large in propor- 

 tion, and the strise being very much slighter. 



Gmelin made one of his usual blunders in changing 

 the name which Miiller gave this species to nitens ; and 

 Draparnaud, apparently without any reason, substituted 

 in his ' Histoire ^ a new name {lucida) for the correct 

 one which he had previously given in his ^ Tableau.' 



7. Z. excava'tus*. Bean. 



Helix excavata, Bean, in Alder's Cat, North. Moll. p. 13. Z. excavatus, 

 F. & H. iv. p. 40, pi. exxi. f. 2-4. 



Body lead-coloured (Alder). 



Shell compressed, more convex on the upper than the 

 lower side, glossy, semitransparent, light-brown or tawny, 

 strongly and deeply striate in the line of growth : ejyidermis 

 rather thin : whorls 5-^, convex and nearly cylindrical, the last 

 occupying not much more than one-third of the shell : spire 

 slightly prominent : suture very deep : mouth round, except 

 where it is interrupted by the penultimate whorl, somewhat 

 compressed below : outer Jlp as in the last species : umbilicus 

 broad and deep, exposing all the internal spire. L. 0*085. 

 B. 0-225. 



Var. vitrina. Shell greenish-white, transparent. Helix vi- 

 trina, Fer. Tabl. Syst. p. 45. H. viindula, Menke, Syn. Moll, 

 p. 20. 



* Hollowed -out. 



