88 LAND AND FRESH-WATER SHELLS. 



small, narrow. Height -^ths inch. Among moss and dead 

 leaves; under stones and the bark of old trees. Common. 



(d) Shell cylindrical, ovate, finely striated, dull brownish horn- 

 colour; whorls six to seven, convex; mouth sub-semicircular, 

 provided with a small denticle placed in the middle of the base 

 of the last whorl, and a strong, white, external rib behind the 

 outer lip ; umbilicus narrow. Height -^ths inch. In moss and 

 under stones on sandy soils. Somewhat local. 



P. muscorum^ 



26. Vertigo. Shell dextral or sinistral, sub-cylindrical with 

 closely pressed, gradually- enlarging whorls ; mouth more or less 

 angular, generally toothed internally ; umbilicus minute. Re- 

 sembles Pupa, but differs in having the ventral tentacles wanting, 

 and in having the peristome thinner. 



(a) Shell dextral, oval, shining, chestnut-brown ; whorls four 

 and a-half, the body-whorl comprising about one-half of the 

 shell; mouth subcordate, with from six to eight reddish-brown 

 denticles ; umbilicus narrow, distinct. Height y^th inch. Under 

 stones in marshy places. Moderately common. 



V. antivertigo.^ 



(b) Shell dextral, oval, ventricose, light yellowish horn-colour ; 

 whorls four and a-half, globose, the body-whorl comprising more 

 than half of the shell ; suture exceedingly deep ; mouth semi-oval 

 with four or five denticles ; umbilicus open. Height j^th inch. 

 Rare. V. moulinsiana. m 



(c) Shell dextral, ovate, somewhat cylindrical, reddish brown ; 

 whorls four and a-half to five, the body-whorl occupying about 

 one-half of the shell, convex ; mouth semi-oval with four or five 



83 v. edentula, without denticles ; v. albina, entirely white. 



84 v. albina, whitish, unicolor ; v. bigranata, with a dentiform palatal 

 callosity. 



85 v. sexdentata, with six denticles; v. octodentata, with eight den- 

 ticles. 



86 v. bidentata, labial or palatal teeth wanting ; v. lilljeborgi, shell less 

 swollen and barrel- shaped and with the labial rib less stout. 



