A MANUAL OF AMERICAN LAND SHELLS. 



33 



Folygyra auriformis. 

 Stenotrema stenotremum. 

 Jiirsutum. 

 monodon. 

 Triodo2}sis palliata. 

 ohsiricta. 

 uppressa. 

 inflecta. 

 tridentata. 

 fallax. 

 Mesodon albolahris. 



multilineatus. 

 Pennsylv aniens . 

 Mitcliellianus. 

 elevatus. 

 exoletus. 

 dent'iferus. 

 thyroides. 

 clausus. 

 profundus. 

 Say a. 

 Acanthinula harpa. 



Valloniapulchella. 

 Pupa muscorum. 

 pentodon. 

 fallax. 

 armifera. 

 contracta. 

 rupicola. 

 , corticaria. 

 Vertigo milium. 



ovata. 

 Succinea retusa. 



Grosvenori. 

 3fooresiana. 

 ovalis. 

 lineata. 

 avara. 

 aurea. 

 ohliqua. 

 Totteniana. 

 Tebennophorus Garoliniensis. 

 dorsalis. 



The above list shows the Interior Eegioii to be remarkable for the 

 develoijment of the section of Zonites familiar by the European Z. oli- 

 veiorum {Mesompliix of Alb. ed. 2). Of the disintegrated genus Helix 

 the section or genus Mesodon is most developed. This is almost exclu- 

 sively a iS'orth American subgenus, as is also Triodopsis, which is also 

 greatly developed in the Interior Eegion. 



In addition to the species included in the above list as inhabiting all 

 of the Interior Region, there is a large group of species found within 

 its limits, but having a more restricted range. They are found in what 

 may be called the Cumberland* Subregion. This is comprised in the 

 southern portion of the Appalachian chain, situated in Eastern Ten- 

 nessee and the adjoining counties of North Carolina, with an offshoot 

 into the mountains of West Virginia.! 



* This name was adopted, from the circumstance of Bishop Elliott first showing the 

 richness of the subregion on the Cumberland table-lauds. 



tFora description of its physical and climatic characters, see Torr. Moll. U.S., 

 Vol. I, 122. It is there designated as the Southern Interior Section, and is given a 

 wider western range. 



1749— Bull. 28 3 



