38 THE NAUTILUS. 



the name of Mr. W. G. Binney has not yet been given to one of the 

 genus, Mr. Ferriss unites with me in calling this one Polygyra Bin- 

 neyana n. sp. (Binney's Mesodon). 



It may best be described by a comparison with the most nearly 

 allied species, P. divesta (GUI.). Shell of about the same depressed 

 form as the large variety of P. divesta, narrow, its width contained 

 15-18 times in that of the shell, and half covered by the reflexed but 

 not appressed lip. Color, brownish-yellow. Sculpture similar to that 

 of the large variety of divesta, the surface being glossy and finely 

 striated, showing under a lens very fine, close spiral stria?. Whorls 

 5^, rather slowly increasing, the last becoming much wider, rounded 

 at the periphery, a little detlexed in front, constricted behind the 

 peristome. Aperture oblique, elliptical-lunate ; peristome rather 

 narrowly reflexed, with its face rounded and the edge a little re- 

 curved ; baso-columellar margin arcuate, sometimes showing a very 

 slight median callus. 



Alt. 12^, diam. 22 mm. (Hardy). 



Alt. 11, diam. 19^ mm. (Tushkahoma). 



Typical P. divesta is very much more coarsely striated, with the 

 umbilicus wholly covered by a well-developed, appressed callus, as in 

 P. albolabris. 



P. Binneyana occurred at Hardy, Sharp Co., in northern central 

 Arkansas, and at Tushkahoma, Choctaw Nation. 



Polygyra divesta was originally described from Arkansas, no special 

 locality being given. The original specimens, of which two from 

 Gould are before me, are very coarsely striated, with the lip flattened 

 and not recurved at the edge, and measure 16^ and 18 mm. in 

 diameter. This rather coarse form is before me from the following 

 localities : 



Louisiana: Grand Cane, De Soto Parish, in N.-W. La. (Wil- 

 liamson). 



Arkansas: Mabel vale, Pulaski Co. (C. W. Johnson) and Hot 

 Springs, Garland Co., in the central, and Eureka Springs, Carroll 

 Co. (Sampson) in the northwestern part of the State. Binney gives 

 the locality Washita Springs. 



Missouri : Chadwick, Christian Co., and Springfield, Greene Co. 

 (Ferriss) both in the southwestern part of the State. 



Kansas: Fort Scott, Bourbon Co. (Sampson), on the southeastern 

 edge of the State. 



