8 LYMN.ECEA. 



Family III.^LYMN;ECEA. 



Shell spiral, generally with a smooth external surface; margin 

 of the outer lip always acute, and not reflected. Animals am- 

 pliibious, usually destitute of an operculum. 



Genus V LYMNiEA Lamarck. 



Shell oblong, thin, sometimes elongated and acutely tur- 

 reted ; spire always produced ; aperture large, entire, oblong, 

 generally straitened, and somewhat acuminate above and round- 

 ed below ; outer lip acute ; the lower part of the inner lip 

 ascending on the pillar, forming an oblique plait or fold, and 

 rising, spreads more or less over the columella, or front of the 

 body volution ; external surface smooth, frequently polished. 

 Destitute of an operculum. 



1. Lymn^a stagnalis, pi. I, f. 21, 22. 



Lymnceus stagnalis, Lamarck, An. San. Vert., VI, pt. 2nd, 

 p. 159; Drapernaud, p. 51, pi. 2, f. 38, 39; Pfeiffer, p. 86, pi. 

 4, f. 19; Turton, Man., p. 121, f. 104 ; Alder, Mag. Zool. and 

 Bot., p. 114; Brard, p. 133, pi. 5, f. 1 ; De Montfort, II, p. 

 268; Sowerby, Genera, f. 1 ; Rossmassler, I, p. 95, pi. 2, f. 49; 

 Thompson, Ann. and Mag. Nat. Hist., VI, p. 45; Brown, 

 Illust. Conch., p. 28, pi. 15, f. 18, 19, 21, 22, 23; Stagnicola 

 vulgaris. Leach, Moll., p. 145; Lymneus rnayor, Jeffreys, Linn. 

 Tr., XVI, p. 375 ; Limnea stagnalis, Fleming, Brit. An., p. 

 273; Helix stagnalis, Montagu, Test. Brit., p. 367, pi. 16, f. 8; 

 Donovan, Brit. Sh., II, pi. 51, f. 2; Brown, Wernerian Mem., 

 II, p. 530. 



Shell very thin, brittle, oblong-oval, subulate, pellucid, and 

 horn-coloured; body large, longitudinally striated, generally 

 crossed by a few raised spiral ridges ; spire acute, consisting of 

 five or six volutions, tapering to a fine point, and separated by a 

 deep suture ; aperture oval, a httle narrower above than below, 

 and occupying more than half the length of the shell ; outer lip 

 thin, but not reflected; pillar lip reflected on the columella, with 

 an oblique fold, behind which is a slight umbilicus. 



This shell is subject to some variety. Fig. 23, 24, pi. I, is 

 a thin and less ventricose variety, to which Montagu gives the 

 specific name oi fragilis, p. 369, ph 16, f. 7. 



Fig. 25, pi. I, is the representation of a young shell. 



