24 STROBILOPS, CANADA AND UNITED STATES. 



1&. Strohilops lahijrinthica form parietalis, new form. PL 9, 

 figs. 10, 11. 



Similar to iS^, Idbyrinthica in the eonvexly conic, ribbed shell 

 and weakly emerging infraparietal lamella, but the lamellee 

 penetrate more deeply, being between tivo-thirds and three- 

 fourths of a whorl long (fig. 10), There is a blunt columellar 

 lamella and four basal folds, four within the side wall (fig. 

 11, oblique view of baso-palatal folds). The whole base is 

 ribbed in some examples, or smoothish, merely finely striate 

 in others. Height 1.75, diam. 2.35 mm. 



The type locality of this form is Ardsley, Montgomery Co., 

 Pennsylvania (Bayard Long) ; but very similar examples are 

 before me from Gray Bluff, Marion Co., Tennessee; Lookout 

 Mountain, near Valley Head, and Blount Spring, Alabama 

 (H. H. Smith) ; Talahassee, Florida (C. W. Johnson) ; and 

 Catahoula Parish, Louisiana, 1.55 x 2.15 mm. (C. B. Moore). 



Most of the southern specimens are rather small, but in a 

 lot from "Woodville, Ala. (H. E. Sargent), the largest meas- 

 ures 2 x 2.7 mm. While it approaches S. texasiana and 

 fioridana by the long parietal lamella, it differs by the de- 

 cidedly less coarse ribbing. The status of this form is doubt- 

 ful; the sporadic distribution, as now known, seems to indi- 

 cate that it is not a subspecies. It is introduced here to induce 

 further investigation, 



2, Strobilops texaslvna Pils, & Ferr. PI, 2, figs. 5 to 11, 



Shell moderately elevated with dome-shaped spire; light 

 bro^vn ; umbilicus contained about 8 times in the diameter. 

 Whorls 514, the first l^/^ smooth, pale-corneous, the rest regu- 

 larly ribbed obliquely, the last whorl rounded peripherally or 

 a trifle and obtusely subangular in front, the riblets passing 

 over undiminished upon the base, which is as strongly sculp- 

 tured as the upper surface (or sometimes smoothish just in 

 front of the aperture) , Aperture with slightly expanded, well 

 thickened, whitish peristome and a strong parietal callus. 

 Parietal lamella emerging to the edge of the callus, pene- 

 trating fully three-fourths of a whorl, Infraparietal lamella 

 less emerging, being very shortly and weakly visible in a basal 



