1906.J NATURAL SCIENCES OF PHILADELPHIA. 555 



Measurements {diameter) of Polygyra zaleta ozarkensis. 



Of this species only two or three, at most, of the lots taken are suffi- 

 ciently large to be expected to yield normal curves. It would seem 

 however that there is no difference in size between shells from the 

 shady north side of the summit of INIagazine Mountain and those from its 

 dry southern slope. The Poteau Mountain and Petit Jean Mountain lots 

 are from northern exposures, but these mountains are rather dry. The 

 Sugar Loaf lot is from shady, leafy ravines, but not especially well 

 watered or damp. The snail however is not one which affects moist or 

 rocky situations. It lives preferably on slopes leaf -carpeted over a rich 

 humus, and rolls out of the leaves where one is raking for Omphalina. On 

 the north side of Magazine Mountain we took them on the leafy slope 

 just below the great rock-talus. 



From localities in Arkansas other than those tabulated but few (one 

 to three) specimens have been seen. They agree with those in the table 

 with three exceptions : At Rich Mountain Mr. Ferriss took two speci- 

 mens, 23.5 and 26 mm. in diam. ; in Little River Co. three taken measure 

 24.25 and 26.5 mm.; and two from Little Rock are large and heavy, 

 26 and 27.5 mm. These larger shells approach the eastern P. zaleta, 

 and indeed intergrade with that in size. 



Polygyra elevata (Say). PL XXII, figs. 22-25 (Hardy. Ark.). 



Sampson, Kansas City Re\aew of Science and Industry, February, 1883, 



p. 551 ; Bull. Sedalia Nat. Hist. Soc, August, 1885, p. 19. (Sedalia, Mo.) 

 Moll, of Arkansas, Ann. Rep. Geol. Surv. 1891, p. 190. 



