THE NAUTILUS. 



VOL. XIII. AUGUST, 1899. No. 4, 



NEW SOUTHWESTERN FORMS OF POLYGYRA. 



BY H. A. PILSBRY. 



Mr. James H. Ferriss made a journey through Arkansas and the 

 Choctaw Nation of Indian Territory, during February of this year. 

 It was too early in the season for the best results with snails ; they 

 were partially torpid, and not readily flushed from cover; and while 

 some log-rolling had to be done, Mr. Ferriss missed the excitement of 

 moving half a ton of rock for each one, as he was accustomed to do 

 in the Smokies. Nevertheless, some interesting things were collected. 

 Near Texarkana, Ark., on the Red River, numerous specimens were 

 taken of a variety of Polygyra Dorfetn'lliana, agreeing with var. 

 Sampsoni Wetherby, in the ample umbilical region, but differing in 

 the heavy rib-striation of the whole base (Sampsoni being nearly 

 smooth beneath), and in the almost marginal position of the upper 

 lip-tooth, which is less immersed than in any of the other forms of 

 the species. This form may be known as var. percostata. But Fer- 

 riss' greatest success was in stalking big game. It isn't everybody 

 who can find unknown Polygyras nearly an inch in diameter; and 

 Mr. Ferriss is prouder of it than a boy with a new knife. 



The new form was at first thought to be P. kiowa'ensis var. arkan- 

 saensis, but a comparison with the types of that shell shows the new 

 one to be quite different. As not many more large and distinct new 

 Polygyras can reasonably be expected in these United States, and 



