PHYSA. 33 



Var. albino, . White, not uncommon. 



11. P. CONTORTUS (twisted up). 



Flat above, very convex below, dull brown ; whorls eight, 

 compressed; suture deep-, mouth crescent- shaped ; umbilicus 

 deep. 



This is a compact-looking little shell, and when once 

 seen is never confounded with any other. It is fairly 

 common on weeds in ponds and ditches. 



Var. albida. Whitish. 



10. P. DILAIATUS {expanded). 



Mattish above, extremely convex beneath ; whorls two 

 to two and a half, dull ; nearly opaque ; mouth exceedingly 

 expanded, and very large ; suture distinct ; umbilicus 

 narrow, but deep. 



This little shell was imported from America in cotton 

 bales. It was first noticed by Mr. T. Rogers, of Man- 

 chester, in 1869. The only two places where it has 

 yet been observed to have made itself at home are the 

 Bolton Canal and the Reddish Canal (between Stock- 

 port and Manchester), where there are cotton mills. 



Genus II. PHYSA. 



1. P. HYPNORUM (frequenting the Hypnum, a moss). 

 Sinistral, spindle-shaped, thin, highly glossy, semi-trans- 

 parent, dark reddish horn-colour; whorls six to seven. 



D 



