94 AMERICAN SPECIES OF VERTIGO. 



3. Ovate-conic, with a strong palatal callus; British 

 Columbia. V. v. elatior, no. 8a. 



Cylindric-oblong ; palatal callus very weak or wanting; 

 Washington to California. V. andrusiana, no. 19. 



(Eastern species, Atlantic to Rocky Mountain's). 

 8. VERTIGO VENTRICOSA (Morse). PL 7, figs. 1, 2, 3. 



' ' Shell umbilicate, ovate, conic, smooth, polished ; apex ob- 

 tuse ; suture deep ; whorls four, convex. Aperture, semi- 

 circular, with five teeth, one prominent on the parietal margin, 

 two smaller on the columellar margin, and two prominent 

 within, contracting the aperture at the base ; peristome widely 

 reflected, the right margin flexuose, within thickened and 

 colored. Length .07 inch ; breadth .45 inch" [1.75 x 1.1 mm.] 

 (Morse). 



Magdalen and Prince Edward Is., Quebec, New England 

 and New York, west to Ohio, Michigan and Illinois. 



Isthmia ventricosa MORSE, Ann. Lye. Nat. Hist. N. Y. viii, 

 Nov., 1865, p. 207, fig. 1. Vertigo ventricosa Morse, BINNEY, 

 Terr. Moll, v, 1878, p. 218. STERKI, 8th Ann. Rep. Ohio 

 State Acad. Sci., 1900, p. 32 (Tuscarawas Co., 0.).- 

 WHITEAVES, Ottawa Naturalist 1905, 171 (Riviere du Loup, 

 Quebec). NYLANDER, Nautilus xiii, 103 (Aroostook Co., Me.). 

 -HANHAM, Naut. x, 101; xi, 111 (Isle d 'Orleans, Quebec). 

 WHEAT, Naut. xx, 161 (Cayuga L., N. Y.). BLANEY, Naut. 

 xviii, 46 (Ironbound I., Me.). WALKER, Moll, of Michigan, 

 1906, p. 517, f. 150 (Grand Rapids and Beulah, Benzie Co.). 

 JOHNSON, Fauna of New England no. 13, 1915, p. 214 (Me., 

 N. H., Conn.). V.[ertigo] approxinians STERKI, Nautilus 

 iii, 1890, p. 136. 



The author has seen typical ventricosa only from Canada, 

 New England and New York, but it has been reported by 

 Walker and Sterki from states bordering the Great Lakes as 

 far west as Illinois. 



V. ventricosa differs from V. ovata by the constantly 

 smaller size, absence of an angular lamella, and smaller num- 

 ber of teeth. It is of an auburn color, somewhat transparent, 

 glossy, with only a trace of striation. Under a high power 



