xlvii 



Among the tuberculate species, I have included 

 G. occata, Hinds, — a California shell, of very 

 doubtful generic character. 



The plicate sj^ecies number eighty-five, of which 

 about half inhabit the Tennessee River. A few of 

 these extend into the Cumberland, and one or tw^o 

 to the Green River, of Kentucky. 



On the other side, a very few (five only) of the 

 plicate species are found also in the Coosa and 

 Black Warrior Rivers. Five species occur in Oregon 

 and California. One species is reported from South 

 Carolina, and two from Florida. The Ohio and 

 Illinois Rivers each possess a species ; and several 

 occur in the Flint and Savannah Rivers, of Georgia. 



G. sutnrales, Haldeman, reported from Ohio, is 

 more likely a Georgia species, identical with one 

 recently described by Mr. Lea. 



Twenty-seven angulate species are about equally 

 distributed in the Coosa and Tennessee Rivers. 

 One of them, sordlda, Lea, occurs both in the 

 Cumberland and in Saline River, Arkansas. 



G. Potosiensis, Lea, is found in St. Francis River, 

 Missouri, 



G.proxima, Say, occurs in the Holston and Santee 

 Rivers. 



G. hicincta, Antli., inhabits the Cahawl^a, Chatta- 

 hoochee, Savannah, Roanoke, and is also reported 

 from North Carolina and Arkansas ! 



Mr. Anthony's habitat, "Ohio," for his G. tecta is 

 an error ; the shell is known to come from the 

 Coosa River. 



It is also very doubtful whether the specimens 

 of Mr. Lea's G. SjKirtanhuryensis, from the Ohio 

 River and from South Carolina, really belong to 

 the same species. In such cases the authority for 

 the alleged habitats shoukl be rigorously investigated. 



Of the twenty-six short, clavate, smooth species, 

 a small group, with daik-colored, inflated shells, is 

 quite characteristic of East Tennessee and southern 



