COLIMACEA. 39 



This species is subject to some variation in colour and dia- 

 meter; some specimens being of a greenish-yellow, while others 

 are more ventricose in the centre ; it also differs a little in 

 length. 



The favourite resort of this species is a calcareous soil; it 

 is to be met with in woods of beech trees, and has been found 

 at Bow Wood, the scat of the Marquis of Lansdowne, Lack- 

 ham Wood, Wiltshire ; and I found it, of a large size, on the 

 bark of a decayed tree at Hexham ; and at Dove Dale, Derby- 

 shire, by William Thompson, Esq. It has been found at 

 Belamont Forest, near Coothill, County of Cavan, Ireland, by 

 my friend T. W. Warren, Esq., of Dublin, and on trees, in 

 the demesne of Florence Court, County of Fermanagh, by that 

 able conchologist, William Thompson, Esq., of Belfast. 



This is a very local species, and certainly the most beautiful 

 of our native Clausilicc. 



Section II. — Shells corrugated; and ivith the clausium 

 entire at the top. 



2. Clausilia biplicata, pi. IV, f. 35, 36. 



Clausilia hiplicata, Leach, Moll., p. 120; Alder, Mag. Zool. 

 and Bot., II, p. 110; Fleming, Brit. An., p. 271; Turton, 

 Man., p. 72, f. 55 ; Clausilia 3Iontagui, Gray, Ann. Phil., p. 

 13; Clausilia verrucosa, Drapernaud, Hist, des Moll., p. 71, 

 pi. 4, f. 11 ; Pfeiffer, p. 63, pi. 3, f. 29; Jeffreys, Linn. Tr., 

 XVI, p. 354; Clausilia similis, Rossmassler, Icon., p. 177, pi. 

 2, f. 30; Turbo hiplicatus, Montagu, Test. Brit., p. 361, pi. 11, 

 f. 5; Helix perversa, adult, Miiller, Verm., II, p. 118; Helix 

 cocholodina ventricosula, Ferussac, pi. 63 ; Clausilia bijjUcata, 

 Brown, Illust. Conch., p. 38, pi. 14, f. 13; lb.. First Ed., pi. 41, 

 f. 13. 



Shell opaque grayish-brown ; with twelve or thirteen reversed 

 volutions ; whole surface covered with numerous, longitudinal, 

 strong, regular, slightly oblique strife; volutions well defined by 

 the sutural line, which is rather deep, and terminating in a 

 somewhat blunted apex; aperture suborbicular, rounded below, 

 considerably compressed above, and a little sinuous at the upper 

 and inner angle; provided internally with two plaits, one situate 

 near the top of the pillar lip, and the other about half way 

 down the base of the columella, their points approximating to 



