North Americcm HelicidcB. 3Y 



H. auriculata, and the rib-like striae, which cover ^i^^- 

 the whole of that shell, are scarcely developed 

 at the base. The form of the parietal pro- 

 cess is very like that of H. uvulifera, but the continuation 

 of its inferior angle to the inner termination of the labrum 

 is not prostrate as in that species, but erect as in H. auri- 

 Gulata. The position and form of the upper tooth on the 

 labrum is much the same as in that species, and in H. uvulifera^ 

 but the lower one is entirely different. In those it is an oblique, 

 strongly developed, convex, sinuous fold on the margin of the 

 labrum, not descending into the aperture, there being within 

 a slight thickening only, corresponding with the lower exterior 

 apertural depression. 



In H. Postellania there is at the base of the labrum a thin, 

 erect, oblong, lamelHform tooth, rather oblique, but more 

 closely marginal than the fold in the other species. The exterior 

 of this tooth is convex, within concave, it is 1 mill, in height, 

 and 1| in length, and descends rapidly into the aperture, where 

 it is recurved, and terminates obtusely opposite to the lower 

 end of the superior tooth, there being a very distinct and tor- 

 tuous sinus between the two. I have opened specimens from 

 different localities, and find these characters constant. 



This is, I believe, the shell which Dr. Binney supposed to be 

 the II. avara Say — specimens from his cabinet, as well as one 

 sent to me by the late Judge Tappan, all so labelled, induce this 

 opinion. The small figures, however, in the Boston Journal, 

 and Terr. Moll, scarcely represent this form. 



I name this species after my liberal correspondent Mr. James 

 Postell, in acknowledgment of the valuable assistance which I 

 have received from him, in my endeavor to elucidate the 

 Korth American Helices. 



Helix aurifbritiis Bland. 



Helix auriculata Binney, Bost. Jl.(ex parte), pi. xix, fig. 2, 1840 

 " " Desk, in Fer. Hist. var. minor, pi. 50, fig. 3. 



