556 PROCEEDINGS OF THE ACADEMY OF [DeC, 



Simpson, Proc. IT. S. Nat. Mus., 1888, p. 450. (Fort Gibson, I. T.) 

 Call, Bull. Washburn College Laboratory of Nat. Hist., I, No. 7, p. 202, 

 December, 1886. (Wyandotte, Kan.) 



Very few records have been made of the existence of this species 

 west of the Mississippi River. The form from this region is in the 

 average smaller than Eastern shells. Some care is required to dis- 

 tinguish it from P. zaleta ozarkensis. A set of fine shells from Spring- 

 field, Green Co., southwestern Missouri (A. G. Wetherby collection), is in 

 the collection of Bryant Walker, who gives the following measurements : 



Alt 17 16.75 16 15.75 15 mm. 



Diam 21.5 20.25 19.75 20.5 20.25 " 



Sampson records P. elevata from Sedalia, Mo. We have not seen 

 specimens. One shell (Ferriss Coll.) was taken by Prof. Stuart Weller 

 near or at Harrison, Boone Co., Ark., measuring 17 x 22.5 mm. At 

 Hardy, Sharp Co., also in northern Arkansas, a series of five taken by 

 Mr. Ferriss measure: 



Alt 15.5 16 16 17 17 mm. 



Diam 215 20 20.5 21.5 22 " 



Whorls 6^ 6^ 6^ 6f 6^ 



Several of these are illustrated for comparison with P. z. ozarkensis,. 

 from which the greater number of whorls and the oblique, straightened 

 basal lip, usually with a tooth and notch at its outer end, distinguish 

 P. elevata. 



Other records from Arkansas are given by Mr. Sampson: Carroll,. 

 Crawford, Clark, Jackson Cos., and Augusta, Woodruff Co. (Call). He 

 remarks that it is "found on low ground or adjacent thereto." P. 

 elevata seems to be a species which has penetrated only the northern 

 edge of the Ozark region. The specimens reported from Fort Gibson, 

 I. T., should be re-examined, for they may prove to be P. z. ozarkensis^ 

 a form easily mistaken for P. elevata. 



P. elevata occurs as a pleistocene fossil in the Mississippi river bluffs 

 at Alton, 111., and Natchez, Miss. 

 Polygyra thyroides (Say). 



Taken by us at Chadwick, Christian Co., Mo.; Rogers, Benton Co., 

 and Mammoth Spring, Fulton Co., Ark., and in Indian Territory at 

 Wyandotte, Wyandotte Nation, Vinita, Cherokee Nation, and Wister, 

 Choctaw Nation. Also at San Marcos, Hays Co., in central Texas, and 

 reported by Ferriss from Smithville, Tex. 

 Polygyra clausa (Say). 



Chadwick, Christian Co., Mo.; Mammoth Spring, Fulton Co., Ark.; 

 Vinita, Cherokee Nation, I. T, 



