Ill 



in the shell being much more swollen, and having the 

 last whorl and mouth excessively large in proportion 

 and the spire consequently smaller. The rows of very 

 minute longitudinal strige may also be regarded as an- 

 other test of distinction. Young shells are more slender 

 than those of L. peregra. The present species was first 

 described by Lister. 



5. L. STAGNA'LIS*, Linne*. 



Helix stagnalis, Linn. Syst. Nat. ed. xii. p. 1249. Limnceus stag- 

 nalis, F. & H. iv. p. 174, pi. cxxiv. f. 4, 5. 



BODY fawn-colour or yellowish- grey with a reddish tint, 

 covered with very small brown and milk-white specks : ten- 

 tacles rather long and pointed :foot having a narrow edge of 

 yellow, very broad at its sides, swollen and keeled behind. 



SHELL elongated, of a moderate thickness, semitransparent, 

 yellowish-horncolour or greyish-white with sometimes a 

 slight tinge of red, irregularly striate by the lines of growth, 

 with extremely fine and close-set interstitial striae, which are 

 curved and arranged in rows, and regularly but indistinctly 

 ridged in a spiral direction, so as to form, by intersecting the 

 longitudinal striae, quadrangular facets, resembling those of 

 cut glass : epidermis thin : whorls 78, rather convex and 

 bulging out in the middle, the last occupying nearly three- 

 fourths of the shell : spire oblique, much produced and taper- 

 ing to a fine point : suture moderately deep, margined above 

 by a narrow white line, which is formed by the upper edge of 

 the preceding whorl : mouth oval, interrupted on its inner side 

 by the periphery of the penultimate whorl and the columellar 

 fold : outer lip rather thin and slightly reflected : inner lip 

 spread on the columella and thickened in adult specimens : 

 fold prominent and very strongly curved. L. 2. B. 1. 



Var. \.fragilis. Shell smaller, more slender and tapering. 

 Helix fragilis, Linn. Fn. Suec. 2187; Mont. Test. Brit. p. 369, 

 tab. 16. f. 7. 



Var. 2. albida. Shell of the last-mentioned form, but of a 

 white colour. 



* Inhabiting ponds. 



