30 LIMN /©IDZ. 
It is a common species, found as far north as 
Aberdeenshire. 
Var. Draparnaldi. Striz in line of growth stronger. 
5. P. @naBer (smooth). 
Convex above, with a depression in the centre; concave 
underneath, rather thin, glossy, horn-colour, finely striated 
transversely, and still more faintly spirally; whorls five; 
suture very deep; mouth nearly circular ; wmbilicus large. 
This is a very local shell, bemg only found in a few 
places in England, among which are Northumber- 
land, Durham, Somerset, Norwich, and Birmingham. 
It resembles P. albus in shape, but is smooth and 
glossy. It is more liable, perhaps, to be taken for the 
young of P. complanatus, as the young of that species 
is only very faintly keeled. 
6. P. sprroRBis (circular coil). 
Very flat, rather solid, glossy, brown horn-colour ; whorls 
five to six; faintly carinated on the lower margin. 
This is a common shell throughout the British Isles. 
It is abundant on pond vegetation, and is often found 
eroded by infusoria, or with a black coating of mud, 
which is very hard to remove. 
Var. ecarinata. Smaller, grey, no keel, only four 
whorls. 
