18 LYMN.ECEA. 



Ireland. It abounds in the Thames, at Battersea; large and 

 beautiful specimens are to be met with in a ditch, near May- 

 nooth, County of Kildare ; is met with near Naas, and near 

 Lea Castle, Queen's County, Ireland. 



2. Planorbis albus, pi. Ill, f. 30, 31. 



Planorhis albus, Miiller, Verm., II, p. 164; Pfeiffer, p. 80, 

 pi. 4, f. 9, 10; Leach, Moll., p. 156; Jeffreys, Linn. Tr., XVI, 

 p. 387 ; Fleming, Edin. Ency., VII, p. 69 ; lb., Brit. An., p. 

 278; Brown, lUust. Conch., p. 31, pi. 14, f. 52, 53; lb.. First 

 Ed., pi. 41, f. 52, 53; Turton, Man., p. 114, f. 97; Alder, Mag. 

 Zool. and Bot., II, p. 113; Forbes, Mai. Mon., p. 13; Thomp- 

 son, Ann. and Mag. Nat. Hist., VI, p. 48; Planorhis hispidus, 

 Drapernaud, p. 43, pi. 1, f. 45, 46, 47, 48; Lamarck, An. San. 

 Vert., VI, pt. 2nd, p. 154 ; Brard, p. 159, pi. 6, f. 6, 7 ; Helix 

 alba, Montagu, Test. Brit., p. 459, pi. 25, f. 7 ; Brown, VVer- 

 nerian Mem., II, p. 524 ; lb., Ency. Brit., VI, p. 458. 



Variety 1 . Shell smooth, shining, and white. 



Planorhis glaher, Jeffreys, Linn. Tr., XVI, p. 3S7. 



Shell dextral, thin, pale yellowish-white, subpellocid, depres- 

 sed ; body volution very large, rounded on the sides ; spire 

 consisting of four rapidly decreasing volutions, which are equally 

 convex both above and below ; the apex of the spire somewhat 

 sunk, forming a subumbilicus, and the under surface more 

 concave ; whole external surface covered with fine, elevated, 

 close-set, transverse, and spiral striae, producing a reticulated 

 appearance, which are provided with dicidous bristles; aperture 

 very large, sublunate, somewhat higher than wide, clasping the 

 body volution ; outer lip thin, a little oblique ; pillar lip white 

 internally, spread on the columella, and continuous with the 

 margin of the outer lip. When recent it is covered with a fine 

 pilous epidermis. 



Found principally in stagnant waters, ponds, and ditches, and 

 by no means a plentiful species. Mr. Thompson says it pre- 

 vails generally over Ireland. 



3. Planorbis LiEVis, pi. Ill, f. 37, 38, 39. 



Planorhis Icevis, Alder, Catalogue, Sup. Trans. Newcastle 

 Nat. Hist. Soc, II, p. 337 ; lb., Mag. Zool. and Bot., II, p. 

 113; Thompson, Ann. and Mag. Nat. Hist., VI, p. 48; Brown, 

 Illust. Conch., p. 31, pi. 18, f. 7, 8, 9- 



Shell smooth, scmitransparent; volutions equally convex both 



