114 AMERICAN SPECIES OF VERTIGO. 



21. VERTIGO HANNAI Pilsbry, n. n. PI. 12, fig. 12. 



"Shell light brown; ovate in outline. Lines of growth 

 faint and oblique. Whorls, four and a half, well rounded, 

 and the sutures well impressed. Apex smooth and white and 

 obtusely pointed. Peristome thin and sharp, slightly ex- 

 panded and the ends connected across the body whorl by a 

 thin deposit of callus, almost no indentation in the upper 

 palatal wall. Aperture semicircular and with six teeth. Two 

 on the parietal wall, both of which are lamellar in shape, and 

 the angle tooth is the smaller of the two, one columellar in 

 the center of that wall of the aperture. This tooth is bifid, 

 that portion toward the apex of the shell being the larger. 

 One basal tooth, small and nodule-like. Two palatals, both of 

 which are lamellar in shape, the lower one of which is the 

 larger. Variation in the large series of this species is slight " 

 (H. & J.). 



Length 1.77, diam. 1.04 mm. 



Length 1.74, diam. 1.04 mm. 



Length 1.63, diam. 1.04 mm. 



Length 1.55, diam. 1.04 mm. 



Kansas: Phillips County, along Prairie Dog creek between 

 Norton and the Eepublican river, Pleistocene, Hanna and 

 Johnston; type in U. S. N. M. no. 226396. 



Vertigo martini HANNA and JOHNSTON, Kansas University 

 Science BuUetin vii, no. 3, Jan., 1913, p. 120, pi. 18, f. 3. 

 Not V. martini Sayn, 1911. 



"This and Vertigo ovata are the only species found in this 

 part of the country with two teeth on the parietal wall. The 

 latter species, however, is much the larger and more ovate in 

 outline. The size of martmi is about the same as that of 

 gouldi from the same deposits, but that species is more cylin- 

 drical and the angle tooth is never developed. The size is 

 somewhat less than that of Vertigo tridentata, a recent shell 

 of Eastern Kansas in which the basal tooth is absent" 

 (H. & J.). 



The entire absence or merely indistinct trace of a crest be- 

 hind the lip, the slighter "auricle" of the latter, and the 



