Some Notes on American Land Shells. 33 



SOME JSrOTES ON- AMERICAN LAND SHELLS. 



By A. G. Wetherbt, 

 Prof, of Geolog}^ and Zoology, Universit}^ of Cincinnati. 



H. {Stenotrema) hirsuta, Say. — Tliis abundant and well-known 

 species exhibits two veiy remarkable varieties in Kentucky and Ten- 

 nessee. The one is a small, thick-shelled, globular variety, which 

 wants the hirsute covering of the t3'pical specimens of the species, and 

 which inhabits the dry ridges and plateaus of the carboniferous forma, 

 tion known as the " Pine Barrens.'' Here it lives under logs in the 

 dryest situations, in company with II. {Patula) perspectiva^ Say, and 

 H. (Zonites) interna, Say. In the same region, and in similar sta- 

 tions, I have found but two other species, the H. [Zonites) chersina, 

 Say, very rare, and the II. (Zonites) intertexta.^ Binney. None of the 

 shells associated with it seem to have undergone much, if anj^ varia- 

 tion from the normal type, a fact of peculiar significance. 



The other variety is almost the opposite of the above. It is much 

 larger than the t3-pe, has the spire either very much elevated and con- 

 ical, or very much flattened; the shell is much thinner when compared 

 with the size than in the previous variety, and the epidermis is hirsute. 

 The periphery of the specimens with the depressed spire is often 

 carinate. In size it equals the largest specimens of II. (Stenotrema) 

 stenotrema, for which this variety has often been taken, and which 

 name I have found it bearing in various collections. 



As I had always found these varieties b}^ themselves, previous to 

 last summer, the small one in the regions above mentioned, and the 

 larger in the subcarboniferous limestone belt surrounding it, I had 

 arrived at the too hasty conclusion that they were varieties due to 

 station. During the past 3'ear, however, I found the two forms 

 together in Pulaski county, Kentucky, even under the same logs. It 

 now becomes clear that we must look elsewhere for the causes of these 

 variations. 



II. (Stenotrema) edvardsi, Bland. — This species was described by Mr. 

 Bland, in 1858, the type having been collected by Mr. W. H. Edwards, 

 the well-known entomologist, in Fayette and Green Brier counties of 

 Virginia. The shell escaped the notice of collectors from that time 

 until I found it in Laurel and Whitley counties, Kentuckj^, in August 

 of 1875. Since then I have found it to be widely distributed in the 

 dry oak forests between King's Mountain, Kentuckj^, on the Cincin- 



