1906.] NATURAL SCIENCES OF PHILADELPHIA, 129 



sometimes concealed in the shelter of the downward-drooping dead 

 leaves on standing Yuccas. From this region they have been washed 

 into the Devil's river, where bleached shells are abundantly found in 

 the drift debris. 



We also took specimens in the high land along the Pecos river, near 

 the High Bridge (Viaduct, on some maps), east of the river, and in 

 drift debris in the canyon. 



In the interior counties of Texas we took specimens in the drift of 

 the Hondo river, Medina county, about two miles north of Hondo. 



Much farther northward Mr. Ferriss found hyperolia at Colorado 

 City, Mitchell county, Texas. 



In New Mexico Prof. J. D. Tinsley collected it on South Spring 

 creek, near Roswell, in the Pecos valley, where it occurred fossil in a 

 bed of white marl, three to four feet below the surface. It is not now 

 found living in that locality. We are indebted to Prof. CockereU for 

 these specimens.'' 



P. t. hyperolia varies about as much as texasiana in size. Specimens 

 from west of Devil's river measure from 3.8x8 mm., with 4^ whorls, 

 to 4.2 X 11 mm., with 5 whorls. 



This variety is not the Helix {Poly gyro) tamaulipasensis of Lea, 

 which is typical P. texasiana, as I have ascertained by a comparison 

 of the type kindly made for me by Dr. W. H. Dall. 

 Polygyra texasiana texasensis (Pils.). PI. V, figs. 11, 12. 



Polygyra texasensis Pils., Nautilus, XVI, p. 31, July, 1902. 



Similar to P. t. hyperolia in the depressed shape and smooth surface, 

 without riblets above; but decidedly larger, with about 5^ whorls, 

 the umbilicus broader than is usual in the other forms of the species. 



Alt. 5.2, diam. 12.5 mm. 



Alt. 5.8, diam. 12.5 mm. 



Alt. 5.8, diam. 13.7 mm. 



Colorado City, Mitchell county, Texas ; types collected by James H. 

 Ferriss in 1902, No. 83,258, A. N. S. Pliila. 



This is a large edition of P. t. hyperolia, and further collections from 

 the almost unknown northwestern half of Texas are needed to deter- 

 mine whether it is really distinct enough from that subspecies to call 

 for recognition of the latter by name. In the large series of hyperolia 

 collected there were, however, no forins as large as texasensis. 

 Polygyra mooreana (W. (3. Binn). PI. V, figs. 4-10. 



This species stands close to P. texasiana, but the shell is smaller than 



' Reported as P. triodontoides in The Nautilus, XIII, November, 1899, p. 84. 

 9 



