506 PROCEEDINGS OF THE ACADEMY OF [1896. 



Big Harpeth River, near Bellevue (68346). 



161. Alasmodonta confragosa Say. 

 Reelfoot Lake, Obion Co. (68356). 



162. Alasmodonta edentula Say. 



Big Harpeth River, near Bellevue (68380) ; Watauga River, 

 near Johnson City (68379). 



Very large specimens, length 12.7 cm., from the Big Harpeth. 

 Probably not specifically distinct from A. pennsylvanica Lam. of 

 the Middle States. 



163. Alasmodonta marginata Say. 



Clinch River, above Patton's Ferry (68332) ; Watauga River, 

 near Johnson City (68321), 



164. Alasmodonta minor (Lea). 



South Harpeth River River, 6 miles from Bellevue (69228). 



165. Alasmodonta rugosa Bar. 



Tennessee River, 2 miles above Knoxville (69229) ; Big Harpeth 

 River, near Bellevue (68333) ; Watauga River, near Johnson City 

 (68320). 



166. Anodonta grandis Say. 



Reelfoot Lake, Obion Co. (68382). 



167. Anodonta harpethensis Lea. 



Harpeth River, near Bellevue (69230). 



168. Anodonta suborbiculata Say. 

 Reelfoot Lake, Obion Co. (68351). 



169. Anodonta imbecilis Say. 



Reelfoot Lake, Obion Co. (68322). 



Summary : Pelecypoda, 71 species ; aquatic Gasirojjoda, 41 spec- 

 ies ; terrestrial Gastropoda, 54 species. 



from the M. inargaritifera and monodonta ; and Simpson finds numbers of 

 otlier incongruous elements. 



We are hardly prepared, however, to merge the various groups of " Mar- 

 gariinna" in Unio. Among other disadvantages, a great many specific names 

 would require change, such as the first one of this list ; and then, tliere is a 

 Teal difference (in the hinge teeth) which would be without recognition in 

 nomenclature. It seems to us that although there are a few forms, such as 

 Unio preKnus, in which this distinction is obscure, still in the great majority it 

 holds. The subject is a complex one, which should not be decided hastily, 

 and we can well afford to postpone wholesale changes in specific nomenclature 

 until Simpson, von Ihering and other specialists who are now working upon 

 the Unionidn' with such gratifying results, shall have arrived at a thoroughly 

 mature classification. 



