254 



LAND AND FRESH WATER SHELLS OF N. A. [PART I. 



whirl less, and a more circular columellar margin to the 

 . aperture. 



Buccal plate wide, narrow, not produced in 

 centre, but slightly curving at ends ; cutting 

 edge regularly waved. 



Lingual formula 98 (13 — 1 — 13) ; central 

 and lateral plates notched at outer posterior 

 corners ; central plate square, having three small denticles ; plate 



Fig. 448. 



Fi?. 447. 



Jaw of Vertigo 

 ventricosa. [Mokse.] 



•='c=.c=i:=aci' 



^c 



Fig. 449. 



Lingual meuibrane of Vertiffo ventricosa. [Mcirse] 



indented at base of central denticle, which is the largest ; lateral 

 plates tridentate, inner denticle largest ; uucini minutely notched. 



Tei'tigO simplex, Godld. — Shell minute, cylindrical, obtuse at 

 apex, smooth, chestnut color; whirls five, well roundeil, separated by a 

 deep suture; aperture circular, the peristome nearly con- 

 tinuous, simple or scarcely everted, except at its columellar 

 margin, where it partially conceals a small umbilicus ; no 

 trace of a tooth has been detected in any specimen. Length 

 1| mill. ; breadth half as great. 



Pupa simplex, Gould, Bost. Journ. Nat. Hist. Ill, 403, pi. 



iii, f. 21 (1840) ; IV, 359 (1843) ; Invertebrata, 190, 



f. 121 (1841).— Pfeiffer, Mon. Hel. Viv. II, 302.— 



DeKay, N. Y. Moll. 52, pi. xxxvi, f. 347 (1S43).— 



BiSNEY, Terr. Moll. II, 343, pi. Ixxii, f. 3. 



Vertigo simplex, Stimpson, Shells of New England, 53 (no 



(jescr.).— W. G. Bix.ney, Terr. Moll. IV, 148.— Mokse, Amur. Nat. I. 



670, f. 67, 68 (186&). 



Canada and New England. 



Spurious Species of Yertigo. 



Vertigo contracta, Adams, Gen. Rec. Moll, is the same as Pupa contracta. 

 Vertigo decora, Adams, Gen. Rec. Moll, is the same as Pupa decora. 

 Vertigo minuta, Adams, Gen. Rec. Moll, is the same as Pupa rupicola. 



