548 PROCEEDINGS OF THE ACADEMY OF [Dec. 



Alt. 



Hot Springs | 9.5 



Magazine Mt j ^ 



Kiowa . 8.8 



7.7 



Limestone Gap J ^ 



The number of whorls varies from 5^ to 5^. 



Polygyra binneyana Pilsbry and Ferriss. PI. XXI, figs. 9, 10, 11 (Petit Jean Mts.), 12 (Sugar 



Pils., Nautilus, XIII, p. 38 (August, 1899); Proc. A. N. S. Phila., 1900, p. 

 451, 1903, p. 201. Ferriss, Nautilus, XIV, pp. 26, 27, 28 (July, 1900). 



This beautiful species is closely related to P. indianorum, but is 

 readily distinguished from the typical form of that species by its open 

 umbilicus. It is equally easy to separate it from P. kiowaensis by the 

 larger aperture and comparatively narrower lip, which is less thickened 

 within and more reflexed. It is found only on the mountains,^^ so far 

 as our experience goes, and chiefly under large stones. It commonly 

 does not seem to be found in the same localities with P. indianorum, 

 either the one or the other occupying the ranges where we collected 

 in 1903. Ferriss however got both at Tushkahoma, I. T., a year or 

 two previously. It is now known from the following localities, all 

 of them south of the Arkansas River : 



Arkansas: Magazine Mt., Logan Co.; Petit Jean Mts., at the south 

 border of Logan Co., or the northwestern border of Yell Co. (Ferriss 

 and Pilsbry); Mena, Hatton's Gap and Rich Mt., Polk Co., and Gil- 

 ham and Horatio, Sevier Co. (Ferriss). 



Indian Territory: Sugar Loaf Mt. and Wister, Choctaw Nation 

 (Ferriss and Pilsbry); Tushkahoma (Ferriss); Poteau, 21-24 mm. 

 diam. (Ferriss). 



The specimens from Indian Territory are much smaller than those 

 from Arkansas, as may be seen from the following table, from which the 

 variation curves may readily be plotted. At Sugar Loaf Mt. the mode 

 is at 19.5 mm. and the largest specimen measures 23 mm. in diam., 

 while in Arkansas the mode is at 24 to 26 mm., and the largest speci- 

 men measures 28.2 mm. Curiously enough, at Tushkahoma, where the 

 largest P. indianorum were found, P. binneyana was small. 



'* Ferriss reports it living xinder stones in creek bottoms in Sevier and Polk 

 counties, Arkansas. Nautilus XIV, 26-28. 



