514 MICHIGAN SURVEY, 1905. 



Alt. 4, diam. 1^ mm. 

 Turbo muscorum, Linnaeus, Syst. Nat., ed. X., I., 767, (1758). 



Pupa , W. G. Binney, Man. Am. Land Shells, 78, fig. 40, (1885). 



, Walker, Rev. Moll. Fauna Mich., 17, (1894). 



Var. UNIDENTATA C. Pfr. 



A single denticle on the parietal wall. 

 Pupa unidentata, C. Pfr., Nat. Deutsch L. & S. Moll. I. pi. III., fig. 19-20,. 

 (1821). 



Var. BIQRANATA Rossma?sler. 



Two teeth, one parietal and one basal. 



Pupa bigranata, Rossm^sler, Icon. IX., X., 27, fig. 645 (1839). 



Easily distinguished from all other Michigan species by its stout, cylin- 

 drical form, and strong white rib behind the outer lip. The only localities 

 reported are Grand Rapids and Detroit. The single example from the 

 former locality which I have seen, is the typical edentulous form, but all 

 three forms are represented in the Detroit lot, the unidentate variety, as^ 

 usual, being the most numerous. 



Genus VERTIGO Draparnaud. 



Shell deeply rimate, ovate, spire acuminate, apex obtuse, 

 whorls 5-6, convex, the last rounded, aperture semi-oval, 

 with 4 to 7 folds; peristome scarcely expanded, white lipped. 



Animal as in Pupilla, but lower tentacles wanting. 



Jaw more or less arched, ends but little at- ^TiTTTx. 

 tenuated, blunt; anterior surface with deli- A^/"^ — v\ 

 Fig. 143. cate vertical striae; cutting margin with a ^^ ^— ^ 



Animal of t'^r^iV/o. i i i i j. • ,- Fifj. 144. Jaw of 



(Uach.) more or less developed median projection. y. nvnta. (Binney.) 

 Radula long and narrow; centrals with basal plates higher than wide, 

 sub-rectangular, tricuspid; laterals similar to centrals, but asymmetrical;, 

 marginals low, wide, multidentate. 



Fig. 145. Dentition of V. ovatn. (Binney.) 



KEY TO SUBGENERA OF VERTIGO. 



I. Palatal folds simple, no accessory gular fold Vertigo s. s. 



XL A long gular fold deflected at its inner extremity, connected with 

 one of the palatals Vertilla. 



KEY TO SPECIES OF VERTIGO. 



I. Outer lip flattened, not indented. 



a. Aperture regularly rounded below, two columellar teeth, palatal teeth 



lamellar bollesiana, 



aa. Aperture rounded above, narrower below. One columellar toothy 

 palatal teeth tubercular tridentata. 



