EXPLANATION OF THE PLATE 



Note: — All the figures, with the exception of figs. 14 and 15, are twice enlarged. 

 The specimens shown in figs. 2, 10 and 13 are from the Aldrich, Gould and Lewis 

 collections respectively. All the other specimens figured are from the Beecher col- 

 lection. 



Page. 



Fig. 1. Unio pressus, Lea 175 



Norman's Kill, Albany County, N. Y. 



Fig. 2. Unio Tappanianus, Lea , 176 



Erie Canal, Mohawk, N. Y. 



Fig. 3. Unio luteolus, Lam 177 



Twin Lakes, Wisconsin. 



Fig. 4. Unio radiatus, Lam 178 



Little Lakes, Herkimer County, N. Y. 



Fig. 5. Unio nasutus, Say 179 



Canal, West Troy, N Y. 



Fig. 6. Unio complanatus, Sol 180 



Champlain Canal, West Troy, N. Y. 



Fig. 7. Unio ochraceus, Say 180 



Champlain Canal, West Troy, N. Y. 



Fig. 8. Unio cariosus, Say 182 



Norman's Kill, Albany County, N. Y. 



Fig. 9. Margaritana marginata, Say 183 



Huron River, Ann Arbor, Mich. 



Fig. 10. Margaritana rugosa, Barnes 184 



Locality unknown. 



Fig. 11. Margaritana undulata, Say . . 185 



Norman's Kill, Albany County, N. Y. 



Fig. 12. Anodonta undulata, Say 186 



Norman's Kill, Albany County, N. Y. 



Fig. 13. Anodonta subcylindracea, Lea 187 



Erie Canal, Mohawk, N. Y. 



Fig. 14. Anodonta subcylindracea, Lea 187, 189 



Entire shell, natural size, for comparison with An. Lewisii. 

 Norman's Kill, Albany County, N Y. 



Fig. 15. Anodonta Lewisii, Lea 189 



Entire shell, natural size, for comparison with An. subcylindracea. 

 Norman's Kill, Albany County, N. Y. 



Fig. 16. Anodonta implicata, Say 187 



Champlain Canal, West Troy, N. Y. 



Fig. 17. Anodonta fluviatilis, Dill w 188 



Swamp, Oreenbush, N. Y. 



Fig. 18. Anodonta Lewisii, Lea 189 



Norman's Kill, Albany County, N. Y. 



