STROBILOPS, CAN^yDA AND UNITED STATES. 31 



rower, contained about 8 times in the diameter ; last third of 

 base ribbed. The infraparietal lamella does not emerge. 

 Tliree folds visible thi'ough the base. Height 1.7, diam. 2.5 

 mm. ; 5i/4 whorls. 



Arkansas: Menard Landing, Arkansas Co., Ouachita Co. 

 (C. B. Moore). Louisiana: localities in Morehouse, Richland, 

 Franklin, Catahoula and Rapides parishes (C. B. Moore) ; 

 Grand Cane (Williamson) and Frierson (L. S. Frierson), De 

 Soto Parish; type loc. Boeuf River above Charlieville, Rich- 

 land Parish. Mississippi: Yazoo and Jackson counties (C. B. 

 Moore). Alabama: Wetumpka (H. H. Smith); Simpson 

 Island, Mobile River, Baldwin Co. (C. B. Moore). "Washing- 

 ton, D. C. (E. Lehnert). New Jersey: Barton Run, Burling- 

 ton Co. (Bayard Long). Pennsylvania: Tulpehocken Valley, 

 near Germantown (B. Long). 



This form occurs in the lower Mississippi Valley further 

 southwest than the typical form of the species has been found. 

 By its small umbilicus it approaches the Mexican 8. streheli, 

 in which the ribs are more slender. I considered it a south- 

 western race of ^S'. cBnea until lots from "Washington, D. C, 

 Pennsylvania and New Jersey turned up, in which the um- 

 bilicus is almost as small as in Louisiana specimens — ^being 

 contained 7% times in the diameter. Further collections are 

 required to fix the status of this form, which appears quite 

 distinguishable in the series now available. 



4&. Strohilops cenea spiralis, new subspecies. PI. 9, figs. 5, 6, 7. 



The shell is somewhat less depressed than 8. cenea, light 

 brown ; ribs rather distinct on the base. The parietal lamella 

 is much longer, forming a full whorl in the type (but slightly 

 shorter, over three-fourths of a whorl, in specimens from 

 "Wyandotte, Indiana). The hasal harrier is situated more 

 deeply than in cenea, and consists, as in that species, of four 

 basal folds and a small, short one on the columella. 



Height 1.9, diam. 2.6 mm. Type. 



Height 2.0, diam. 2.6 mm. Paratype. 



North side of the summit of Magazine Mountain, Logan Co., 

 Arkansas {tyipe loc. ; F^rriss and Pilsbrj-, 1903). "Wyandotte, 



