86 



LAND AND FRESH- WATER SHELLS OF N. A. [PART I. 



umbilicus wide ; aperture quite oblique, subcircular ; peristome thickened, 



somewhat reflected, white, not covering tlie umbilicus ; internal 

 Fig. 155. laminae four, two upon the parietal wall of the aperture, of 



which the upper one is much more developed than the lower ; 



the two remaining ones placed deep within the last whirl on its 



base. Greater diam. 2h, height 1\ mill. 



Helix hubbardi, A. D. Bkown, Proc. Acad. Nat. Sci. Philad. 



18(51, 333. 

 Strobila hubbardi, Tryon, Am. Journ. Conch. II, 259, pi. iv, f. 



45 (1866).' 



Found near Indianola, Calhoun Co., Texas. 



Subgenus POLYGYRA, Say. 

 Shell umbilicated or perforated, orbicularly flattened, obliquely 

 and costulately striate ; whirls 5-7^, gradually increasing, the 

 last anteriorly constricted, briefly deflected, inflated below, 

 devious, the penultimate whirl plainly conspicuous, very often 

 constricting the rimate umbilicus; aperture subreniform, or 

 irregularly sinuate ; peristome narrowly reflected, heavy, its 

 margins usually dentate and joined by a 

 triangular, dentiform callus, obliquely enter- 

 ing on the parietal wall of the aperture. 



Animal very small and short in proportion 

 to size of shell, with long, slender eye- 

 peduncles ; shell carried horizontally. 



Fig. 156. 



Animal of 

 Helix fseptemvolva. 



Fig. 157. 



Helix auriculata, Say. — Shell rimately perforated, flattened 

 above, inflated below, with rib-like striae, reddish 

 horn-color or brownish ; whirls five and a half, nar- 

 row, the last deflected at the aperture, disjoined, con- 

 stricted and scrobiculated below ; umbilicus level, 

 showing only the penultimate whirl ; aperture sub- 

 horizontal, ear-shaped, ringent, almost closed; peri- 

 stome continuous, its terminations joined by an 

 oblong, entering, excavated fold, the right margin 

 furnished within with a deep lamellar fold, and form- 



Bete auriculata, 

 enlarged. 



' This figure does not correctly represent the species. In quoting it I 

 mean to say that it was intended to represent the species. The same 

 remark applies to many other figures in the same Monograph. 



