294 HELICID^. 



This is a hardy but sluggish and impassive little mol- 

 lusk^ and lives on the highest mountains as well as in 

 the lowest plains. These habits and the capability of 

 enduring different conditions of climate and temperature 

 may account for the great extent of time and space 

 which it has enjoyed as a species. It is also in some 

 degree amphibious. In consequence of Geoffroy having 

 stated that it was killed by being put in water, and that 

 by this means the animal could be removed from the 

 shell, IMiiller tried some experiments, which convinced 

 him that the French natm^alist was more imaginative 

 than accurate. One of these snails, which Miiller had 

 forced to withdraw into its shell, was plunged into a cold 

 bath, and it immediately thrust out its body ; but, per- 

 haps catching sight of the philosophical experimentalist, 

 and apparently as if resigned to its fate, it staid three 

 hours in the water, when it crawled out and (seemingly 

 pleased at reaching dry land) put out its horns and 

 walked off. However, although they do not mind an 

 occasional soaking, they are often washed down by heavy 

 floods of rain or the overflow of rivers, and their shells 

 occur in great numbers in alluvial deposits. This cir- 

 cumstance will perhaps explain how certain kinds of 

 land-shells so frequently occur in fluviatile, estuarine, 

 or even lacustrine strata. Young shells of C. lubrica 

 are oval or almost globular, and have a slight umbilical 

 perforation. Full-grown specimens vary considerably in 

 size and the length of the spire. The epiphragm is very 

 thin, glistening and iridescent. That made in summer 

 lias a small respiratory hole. In France this sheU bears 

 the appropriate name of " la brillante.^^ 



This species differs from C. tridents in being turreted, 

 instead of spindle-shaped, in the whorls being more con- 

 vex and the suture consequently deeper, but especially 



