LYMN^EHXE OF NORTH AMERICA. 435 



features. The specimens examined show a little variation, some in- 

 dividuals having a regular tapering spire of rounded whorls, while 

 others have the later whorls and body whorl shouldered. The shells 

 range from smooth to strongly malleated and the inner lip varies in its 

 emargination of the umblical chink. Contracta has not been detected 

 outside of the State of Michigan. 



Galba pilsbryana (Walker). Plate XLV, figures 29-31. 



Limnaa sumassi ? WALKER & RUTHVEN, Rep. Geol. Surv. Mich., 1905, pp. 

 51, 52, 53, 97, 99, 1906. 



Lymncea pilsbryana WALKER, Nautilus, XXII, pp. 4, 18, 19, pi. 1, figs. 2, 

 8-11, May, 1908; An. Rep. Mich. Geol. Surv., 1908, p. 290, 1909. 



"SHELL: Ovate-conic, slightly perforate; dark brownish-yellow, 

 frequently tinged with purple, with a light line just below the suture ; 

 whorls 5, convex, with a deeply impressed suture, the three apical 

 whorls small, forming a short conical apex, penultimate whorl twice 

 as long as the three preceding, inflated and convex, body-whorl large 

 and well rounded ; lines of growth strong and regular, cut by numerous 

 fine spiral lines giving a shagreened appearance to the surface, in 

 some specimens the last half of the body whorl is obsoletely malleated ; 

 aperture broadly oval, somewhat more than one-half of the entire 

 length of the shell, dark brownish-yellow within, with a liver colored 

 band just within the lip; lip sharp, regularly rounded and slightly ex- 

 panded toward the basal margin; columella thick, white with a strong 

 fold, broadly reflected over and appressed to the axial region, leaving 

 only a very small perforation, and connected with the upper insertion 

 of the lip by a broad, white and rather thick (for the genus) callus; 

 axis thick, solid, twisted." (Walker). 



Length. Breadth. Aperture length. Breadth. 

 22.00 13.50 13.00 10.00 mill. Type. 



24.00 14.00 14.00 10.00 " 



TYPE: Collection Bryant Walker, twenty specimens, No. 21345; 

 cotypes, Chicago Academy of Sciences, two specimens, No. 23672; 

 Academy of Natural Sciences, Philadelphia. 



TYPE LOCALITY: Washington Harbor, Isle Royale, Lake Super- 

 ior, Michigan. 



ANIMAL, JAW, RADULA and GENITALIA: Not recorded. 

 RANGE: (Figure 48). Isle Royale, Lake Superior. A species of 

 the Canadian region and of the Boreal (Canadian) life zone. 



RECORDS. 



MICHIGAN: Washington Harbor, Isle Royale, Lake Superior (Ruthven; 

 Walker). 



GEOLOGICAL DISTRIBUTION : Unknown. 



