I>L^TE XVII. 



/^^ Page. 



Fig. 1. CoRBUj.A Engkoi-vnni 174 



/J ' ' ''I. A large specitneu, with a part of posterior extremity broken off. 

 Irt. The origiDal typical specimen, enlarged two diameters. 



Fig. 3. CORBULA PYRIFORMIS 170 



2. A side view of a rather distinctly ribbed specimen, with a portiou of its posterior 



extremity broken away, natural size. 

 2a. The original typical specimen, smooth variety. 

 2 &. An anterior view of same, showing its very nearly equivalve character. 



2 c. A very large, irregularly ribbed specimen, with the posterior extremity slightly 



broken. 

 2d. A dorsal view of another specimen, slightly distorted by compression. It shows the 

 posterior dorsal furrow and the angle along the margin of each valve. 



Fig. 3. LiMNJEA SIMILIS 191 



3. A dorsal view, shovN iug aperture, enlarged two diameters. 



3 a. An opposite view of same. 



Fig. 4. Limn.s;a vetusta 191 



4. A dorsal view, natural size. 



4 a. The same, somewhat enlarged. 



4 &. An opposite view of same, enlarged. 



Fig. 5. LiMNiEA NITIDULA 181 



5. Dorsal view, enlarged two diameters. [Inner lip not well shown.] 

 ha. An opposite view of same. 



Fig. 6. Ehytiphorus priscus 175 



6. View of dorsal side (type-specimen). 



6 a. An opposite view of same, showing the narrow aperture, with a part of the lip 



broken away. 



Fig. 7. GONIOBASIS SiMPSONI 193 



7. One of the typical specimens, natural size, with apex broken away. 

 la. A specimen without regular costa. • • 



7 6. An opposite view of same. 

 7 c. A nearly smooth specimen. 



7d. A costate and slightly nodose specimen, enlarged about two diameters. 



Fig. 8. Melania? sculptilis 195 



Side and aperture view, enlarged about two diameters. 

 Fig. 9. Melania ? subsculptius ; perhaps only a variety of last ] 96 



S'de and aperture view, about two diameters. 

 Fig. 10. Carinifex (Vorticifex) Tryoni 188 



10. Side and aperture view, natural size. 

 10 a. View of upper side of same. 



10 6. Under view of same. 



10 c. A young, shongly costate specimen, with the apex much depressed, being the tj'pe 



of the var. concava. 



Fig. 11. CiVHINIFEX (VORTICIFKX) BiNNEYI 187 



11. Side ard aperture view, natural size. 



11 a. View of upper side of same. 



Fig. 12. Ancylus undulatus 186 



12. A medium-sized specimen, natural size, dorsal view. 



12 «. An outline lateral view of same. 



12 6. An outline lateral view of a larger specimen, natural size. 



