CLASSES, ORDERS, ETC. 71 



the body-whorl occupying nearly f ths the length of the shell ; spire 

 acute, tapering ; mouth oval, large. Length i|- to 2 inches. In 

 stagnant and slow-running waters. Common. L. stagnalis.^ 



(f) Shell conical, tapering, thick, opaque, dull brown ; whorls 

 six to seven, convex, the last whorl occupying |rds the length of the 

 shell ; spire produced, acute ; suture rather deep, circled by a 

 narrow white line ; mouth ovate, outer lip marked with brown 

 or violet. Length | to |ths inch. Ponds, marshes, and lakes. 

 Common. L. palustris^ 



(g) Shell oblong-oval, turreted, pale brown or yellowish-horn 

 coloured, rather glossy ; whorls five to six, convex, deeply 

 separated from one another ; spire produced ; apex acute ; suture 

 very deep ; mouth ovate, oblong ; umbilical cleft distinct. Some- 

 what resembles L. palustris. Length ~ inch. Marshes, ditches, 

 pools, and muddy streams. Common. L. truncatula.^ 



(h) Shell tapering, an elongated cone, thin, glossy, horn- 

 coloured or brownish ; whorls seven to eight ; mouth elongate, 

 ovate, not above ^rd the length of the shell, provided with a white 

 internal rib ; umbilical cleft very minute. Length i inch. Ponds 

 and ditches. Local. L. glabras 1 



margin nearly parallel to the columella which is straight, the upper edge reach- 

 ing the commencement of the spire which is sharp ; v. acuta, smaller, more 

 oblong, having the last whorl and mouth proportionably narrower. 



34 v. fragilis, smaller, narrower, thinner, amber-coloured ; v. labiata, 

 dwarfed, with the outer lip thickened and reflected ; v. roseolabiata, slightly 

 narrower, brown-black, mouth bordered interiorly with rose-violet ; v. elegantula, 

 nearly scalariform, suture deep. 



35 v. corva, larger, swollen, opaque, blackish, violet-coloured within ; v. 

 albida, white ; v. obesa, very tumid ; v. conica, conic, greyish-white, suture 

 deep, umbilical cleft present ; v. tinda, shorter, broader, light-brown, mouth 

 purplish ; v. lacunosa, with flattenings, depressions, and protuberances ; v. 

 elongata, slightly larger, slightly narrower, opaque, brown, spire much produced ; 

 m. decollatum, spire decollated. 



36 v. albida, smaller, milk-white ; v. major, larger, ashy, more tumid ; v. 

 ventricosa, more bellied, spire short, peristome without swelling ; v. minor, 

 smaller, horn-coloured ; v. elegans, much larger, more solid, more slender, 

 greyish -white, marked with coarse spiral ridges, spire more produced, suture 

 oblique, outer lip thickened. 



37 v. major, much larger ; v. elongata, more produced, so as to alter the 

 relative proportions of length and breadth ; m. decollatum, spire decollated. 



