VITRINA. 95 



found in the following localities : — Sandhills on Crym- 

 lyn Burrows near Swansea, and in a similar situ- 

 ation on Braunton Burrows, near Bideford, in North 

 Devon (Gwyn Jeffreys), near Glasgow (Kenyon), 

 Baltimore (Mr. Andrew), Cork (Wright and Carroll), 

 B.C., and more recently in the last-named locality 

 by Mr. C. P. Gloyne. 



It may be at once distinguished from the other 

 species by its much smaller shell, which in pro- 

 portion to its size has a much larger spire ; the 

 suture too is deeper and the mouth rounder. The 

 shell is often thinly coated with particles of sand or 

 mud which are caused to adhere to its surface by 

 the slimy secretion of the animal. 



GENUS I I. — VITRINA,'' DRAPARNAUD. 



Body rather slender, usually, but not always, slightly too 

 large to be entirely contained within the shell ; 7nantle demi- 

 shield-like, provided with a lobe on the right side ; tentacles 

 4, cylindrical, upper pair of medium size, lower pair very short ; 

 respiratory orifice on the right side near the lobe of the mantle ; 

 foot somewhat narrow. 



Shell subglobular, very thin and fragile, transparent ; spire 

 short ; month semilunar, somewhat oblique ; timbiliciis wanting. 



These molluscs form a connecting link between the 

 slugs and the true snails, "leading to the former 

 through SiLCcinea and to the latter through Zoiiites" 

 B.C., vol. i. p. 156. Their lingual dentition and shield- 

 like mantle resemble those of Limax, and their shell 

 that of Helix. They are both herbivorous and car- 

 nivorous ; their food consists for the most part of 

 decomposing vegetable matter, but they also devour 



* So named on account of its glassy appearance. 



