102 HELICIDJE. 



pressed at the base, exhibiting externally near the mouth, 

 in the shape of three or four spiral white lines, the traces 

 of the internal laminae ; apex of the spire not particu- 

 larly obtuse. Aperture semi-oblong, rounded below, some- 

 what squared above, not occupying quite one-third the 

 length of the shell, furnished with seven or eight 

 tooth-like folds, of which three are upon the outer lip, 

 with generally a smaller very deep seated one above them, 

 two on the columella, and two are parietal. Of these 

 last, the anterior or lower is the smaller and the deeper 

 seated ; whilst the posterior is large, conspicuous, external, 

 adjacent to, and connected by a callus with the outer lip, 

 and often provided with an additional denticle above it. 

 Peristome white, acute, not broadly expanded, but re- 

 flected over the umbilical chink. 



Length from a quarter to the third of an inch ; breadth 

 not much more than a third that measurement. 



The animal is rather more elongated than its allies ; it 

 is blackish-brown above, pale beneath ; the lower tentacles 

 are very short. 



This is in the main a southern species, though found 

 in limestone localities throughout a great part of Eng- 

 land. It occurs in the Channel Islands, is very abundant 

 on the chalky and limestone districts of the south and west 

 of England, and is plentiful on the limestone of Kendal, 

 in Westmoreland ; it is not found in Scotland, nor in Ire- 

 land ; it is a widely distributed continental shell. When 

 young it invests its shell with mud, a coating which usually, 

 but not always, is dispensed with when it arrives at its 

 full growth. 



