1906.] 



NATURAL SCIENCES OF PHILADELPHIA. 



553 



the 'particular station rather than related to elevation or geologic for- 

 mation. 



It is likely that the specimens from Seligman, Mo., which exhibited 

 two sizes without intermediate forms, commented upon in these 

 Proceedings for 1903, p. 198, were from two stations of diverse physical 

 features. 



There has also been recorded from Daingerfield, Morris Co., Tex., 

 a small form of alholahris, collected by Mr. W. L. McDaniel (J. A. 

 Singley, Contrib. to Nat. Hist, of Texas, Mollusca, p. 305; Fourth Ann. 

 Rep. Geol. Surv. of Texas, 1892). Mr. Singley also reports that a colony 

 of P. alholahris from North Carolina has been established by Mr.' 

 Askew at Tyler, Smith Co., Tex. 

 Polygyra zaleta ozarkensia n. subsp. PI. xxil, figs. 26-29 



Mesodon exoletus Binn., Sampson, Preliminary List of the Mollusca of 

 Arkansas, Ann. Rep. Geol. Surv. of Ark. for 1891, II, p. 190. 



The shell is smaller than P. zaleta (Binn.), with the spire usually more 

 elevated, having somewhat the aspect of P. elevata; whorls 5^, more 

 slowly increasing, the last, in dorsal view, narrower. Aperture with a 

 larger parietal tooth; columellar prominence usually well developed. 

 Bright yellow, usually with a pink under-tint showing through on the 

 spire. The cuticle is often partly or wholly worn from living shells. 



Alt. 16.5, diam. 23 mm. 



