66 HELIX. SNAIL-SHELL. 



Shell horn-color, extremely thin brittle and transparent, 

 very much resembling the last, but is of a more regularly 

 slender form in consequence of the larger volution not be- 

 ing so much larger in proportion to the others, and the 

 line of separation runs more obliquely ; the aperture is 

 also smaller and more oblong ; about a fourth less. 



In the Kennet and Avon Canal, Wiltshire and the 

 Grand Canal, near Dublin, v. v. 



54. Helix palustris. Marsh Snail-shell. 



Pennant, pi. 89. f. 2. A. B. -Montagu, pi. 16. f. 10 

 Linn. Trans, viii. pi. 5. f. 8 Donovan, pi. 175. f. 1, 2 

 Dorset Cat. pi. 18. f. 18. 



Shell brown horn-color, semitransparent, sometimes co- 

 vered with a greyish or brown skin, oftentimes almost 

 black with the inside glossy and dark chocolate brown : 

 spires six, tapering to a fine point, rather rounded, wrinkled 

 longitudinally, and often crossed with a few faint ridges : 

 aperture oval, nearly half as long as the shell; the inner- 

 lip a little reflected, so as to form a slight cavity behind it : 

 length more than half an inch ; breadth one third of its 

 length. 



Watery places : not common, v. v. 



55. Helix fossaria. Ditch Snail-shell. 



Montagu, pi. 16. f, 9 Linn. Trans, viii.pl. 5. f. 9 Dor- 

 set Cat. pi. 18. f. 17. 



Shell horn-color, thin, brittle, transparent, very finely 

 striate longitudinally, but rarely with any transverse lines : 

 spires five or six, tapering to a fine point, much rounded 

 and deeply divided : aperture oval ; the inner-lip hardly 

 reflected, and not forming a cavity behind it. Differs from 

 the last, in not being above half the size, in the volutions 

 being more tumid and deeply divided, and in the aperture 

 being more regularly oval, without the reflexion of the in- 

 ner-lip. 



Wet and muddy places, v. v. 



56. Helix detrita. Three-banded Snail-shell. 



Lister, pi. 108. f. 1 Montagu, pi. 11. f. 1 Dorset Cat. 

 pi, I9.f 26. 



