48 COLIMACEA. 



Genus XIX— VERTIGO.— MuUer. 



Shell subcylindrical, subfusiform, thin and transparent; volu- 

 tions narrow, appearing as if squeezed together, gradually 

 decreasing in size, and becoming abruptly obtuse at the apex ; 

 aperture contracted, sinuated, somewhat angular, toothed inter- 

 nally, marginated ; outer lip subreflected and simple. 



Section 1. — Shells dextral, nearly cylindrical; aperture 

 externally margined. 



1. Vertigo edentula, pi. V, f. 10. 



Pupa edentula, Drapernaud, p. 59, ph 3, f. 28, 29 ; Alder, 

 Mag. Zool. and Bot., II, p. 112 ; Rossniassler, X, p. 28, pi. 49, 

 f. 646; Turton, Man., p. 99, pi- 7, f. 80; Thompson, Ann. and 

 Mag. Nat. Hist., VI, p. 39 ; Vertigo nitida, Ferussac, Tab. 

 Moll.,' p. 64 ; Alcea nitidi, Jeffreys, Linn. Tr., XVI, p. 358 ; 

 Alcea revoluta, Jeffreys, Linn. Tr., XVI, p. 515 and 558; 

 Turbo oftenensis, Sheppard, Linn. Trans., XIV, p. 155; Turbo 

 edentula, Wood, Cat. Sup., pi. 6, f. 14 ; Vertigo edentula, Brown, 

 Illust. Conch., p. 41, pi. 18, f. 36. 



Shell ovately conical, or subcylindrical, somewhat ventricose, 

 of a transparent horn-colour ; spire consisting of four or five 

 well rounded volutions, which are deeply divided by the sutural 

 line, and terminate in a slightly obtuse apex; the whole covered 

 with nearly obsolete striae ; aperture semicircular, destitute of 

 teeth ; outer lip thin on the edge, without a rib behind ; with 

 a very minute umbilicus. Length a tenth of an inch. 



Found in many localities in Great Britain and Ireland. Its 

 favourite resort is marshy situations. Mr. Thompson says, 

 "The typical form of V. edentula I generally find under stones; 

 the elongated and cylindrical variety in woods — in autumn and 

 winter this latter is most readily obtained on the fallen leaves 

 of trees; in summer on the under side of the fronds of ferns." 



The elongated variety has not unfrequently seven or eight 

 volutions, and is often one and a half line in length. 



2. Vertigo pygm^a, pi. V, f. 11. 



Vertigo pygmcea, Ferussac, Tab. Moll^ p. 64 ; Turton, Man., 

 p. 103, f. 83; Alder, Mag. Zool. and Bot., II, p. 112; Thomp- 

 son, Ann. and Mag. Nat. Hist., VI, p. 40 ; Vertigo vulgaris, 

 Leach, Moll., p. 129; Pupa pygmcea, Drapernaud, p. 60, pi. 3, 



