8S LAND AND FRESH-WATER SHELLS. 



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

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



P. timbilicata.^^ 



{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 -^hs inch. In moss and 

 under stones on sandy soils. Somewhat local. 



P. mayginata.^^ 



21. 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 jjth inch. Under 

 stones in marshy places. Moderately common. 



V. antivcrtigo.'^^ 



(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 ; umbiHcus open. Height Yoth'inch. 

 Rare. V. Lilljeborgi.'^^ 



ic) Shell resembling V. Lilljeborgi, but more swollen and barrel- 

 shaped, and with the labial rib much stouter. Rare. 



V. Mouliiisiana. 



{d) 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 



^^ V. cdcntula, without denticles ; v. albina, entirely white. 

 **' V. albina, whitish, ' unicolor ; v. bigj-anata, with a dentiform palatal 

 callosity. 



^^ V. sexdeniata, with six denticles ; v. ocfodentata, with eight denticles. 

 ^^ V. bidentata^ labial or palatal teeth wanting. 



