94 Trans. Acad. Sci. of St. Louis. 



141. Valvata obtusa Drap. 



Station 9. Very common. This is the first record of the 

 occurrence of this species in this country. It is a common 

 European species. 



Subgenus Lyogyrus Gill. 



*142. Valvata pupoidea Gould. 



Mr. Walton reports having found this species near Roches- 

 ter. 



Family Viviparidae. 



Genus Vivipara Lamarck. 



*143. Vivipara contectoides W. G. Binney. 



Mr. Walton reports finding a large number of specimens of 

 this species in the Erie Canal near Pittsford. This is the 

 only record of this species being found in this part of New 

 York. 



Genus Campeloma Rafinesque. 



*144. Campeloma ponderosuji Say. Erie Canal. 



145, Campeloma decisum Say. 



Station 10. Erie Canal (Walton). Very common, buried 

 in soft mud. 

 *146. Campeloma geniculum Conrad. Erie Canal. 



147. Campeloma rufum Haldeman. 

 Station 10. Very common, associated with decisum. Erie 

 Canal (Walton). 



*148. Campeloma integrum DeKay. Erie Canal. 

 *149. Campeloma obesum Lewis. Erie Canal. 



EXPLANATION OF ILLUSTRATIONS. 

 Plate X. 

 1, Polygyra tridentata Say. Pilsbry, Proc. Phil. Acad, Sci. 1894. pi. 1. 

 f. 7.-2, P7 tridentata hidentata Baker. Original.— 3, P. tridentata juxtig ens 



Pilsbry, Proc. Phil. Acad. Sci. 1894. pi. 1. /. 5.-4, P. tridentata 



Original.— 5, P. tridentata unidentata Baker. Original.— 6, P. monodon 

 Rack., double parietal tooth. Oviginsd.— 7-10, By thinia tentaculata Linn^. 

 7, Central tooth.— 8, Intermediate tooth.— 9, First lateral.— 10, Second 

 lateral. All original. 



Issued March 22, 189S. 



