PLATE 45. 



Page. 



Fig. 1. Planorbis vetustus 001 



1, it. Left side of the type-specimen, natural size. 

 1, b. Right side, same, magnified. 



1, c. An aperture view of same, a little more enlarged. 



Fig. 2. Planoebis Nebrascensis GOO 



2, a. Right side of type-specimen, magnified about two diameters. 



2, J. An aperture view of the same, more, highly magnified. [Not represented quite angular 



enough around (he periphery.] 



Fig. 3. Planoebis Leidyi 599 



3,<i, An under or left-side view of type-specimen, natural Bize. 



3, b. An upper-side view of same. 



3, c. An aperture view of same, magnified. 

 3,<i. An umbilical view of same, less magnified. 



Fig. 4. Physa secalina 004 



4. a. An aperture view, magnified about three diameters. 



4, b. An opposite view of same. 



Fig. 5. Limn.ea Meekiana 598 



5, a. An aperture view of a east. 

 5, ft. An opposite view of same. 



5, c. A dorsal view of an imperfect larger specimen. 



Fig. C. Lim.v.ea Shumakdi 599 



6,o. A dorsal view of type-specimen, which is a cast. 



6, b. An aperture view of same. 



Fig. 7. Helix Leidyi 604 



7, a. An aperture view of a cast. 

 7, b. An upper-side view of same. 



