428 The Molluscan Family Planorbidae 



PLATE 96 



Shells of Planorbidae 



1-3. Helisoma oregoneiise (Tiyon). Pueblo Valley on boundary of Oregon, sixty miles 



west of east boundary. Type locality. B1096. 

 4,5. Helisoma oregonense (Tryon). Nevada. Stearns Coll. U.M., 35679. 

 6-8. Helisoma oregonense (Tryon). Sixteen miles northwest of Gerbach, Nevada. 



M.C.Z., 92410. 

 9-12. Helisoma oregonense (Tryon). Variation. Tooele Co., Utah, in salt spring. 



B3920. 

 13-17. Helisoma subcrenatum perdisjectum F. C. Baker. Yellowstone Lake, Wyoming. 



Figure 13, holotype; 14-17, paratypes. U.S.N.M., 30207a. 

 18-22. Helisoma anceps anticostianum F. C. Baker. English Bay, Anticosti Island. 



Fig. 18, holotyi)e; 19-22, paratypes. M.C.Z., 48285. 

 23-30. Helisoma anceps (Menke). Chevanus Pond, north of Knoxville, Tennessee. 



Figures 24, 25, 29, normal anceps; figs. 26, 27, 28. 30, the angistomus form of 



Haldeman; fig. 23, immature. M.C.Z., 46502. 

 31-34. Helisoma magnificum (Pilsbry). Greenfield Pond, near Wilmington, North 



Carolina. Typo locality. Bartsch's figs. Proc. U. S. Nat. Mus., 33, plate 57, figs. 



7-9. U.S.N.M., 193321. 



Figures 1-30 are enlarged about two diameters; 

 figs. 31-34 are about natural size. 



