THE NAUTILUS. 



Vol.. XYni. DECEMBER, 1904. No. 8. 



NEW FORMS OF POLYGYRA FROM ALABAMA. 



BY GEORGE H. OLA IT. 



Polygyra (Stenotrenia^ barb at a n. sp. 



At first glance this species would be readily taken for P. stenn- 

 tremn and as it may exist in some collections under that name it can 

 best be described by comparison with that well-known and widely 

 distributed species. 



Viewed from above, the difference is at once apparent, as barbata 

 has stiff' hairs about - mm. in length which are widely spaced, and 

 the diagonal series cross the lines of growth at nearly a right angle. 

 The upper half of the outer lip is well reflected, not appressed as in 

 stenotrema and there is a distinct constriction back of it. From below 

 the difference is still more striking, a^ the width of the mouth in barbata 

 is tally double that ot s/enotrema ; in barbata the width, measured 

 from the top of the tooth to the edge of the lip just below the notch, 

 is 1 mm., while in a stenotrema of the same size it is only about ^ mm. 

 The lamellif'orm tooth is more sinuous and less massive. The flat- 

 tened upper lip, which is markedly concave, has a well pronounced 

 tooth just opposite the upper end of the abruptly truncated parietal 

 tooth. The " fulcrum," which is plainly visible through the shell, is 

 the most pronounced feature, as it is 3 mm. in length, extending from 

 the axis fully half way across the body-whorl. Embryonic, whorls 

 polished and obsolete!}' ribbed, while in stenulreitta they are granida- 



