THE NAUTILUS. 



Vol.. XXI. AUGUST, 1907. No. 4. 



A NEW SUBSPECIES OF POLYGYRA MTJLTILINEATA. 



BY JAS. II. FERRISS. 



POLYGYRA MULTILINEATA CIIADWICKI n. var. 



This is a dentate form. In a lot of thirty specimens twenty-five 

 had a lunate parietal tooth or thickening of the callus about three 

 mm. in length extending obliquely across the aperture nearer the 

 outer lip. In other respects, compared to multilineata, the shell is 

 heavier, the spire higher, the whorls more ventricose, the suture 

 deeper ; it is moderately polished, the sculpturing is less acute, the 

 furrows shallow ; the aperture is less oblique, less lunate ; the peri- 

 stome thicker, face more rounded, contracting the aperture more. 

 In some examples the parietal callus is a mere ribbon in front of the 

 aperture 5 mm. in width, not extending within the aperture itself. 

 The greatest diameter 21 mm., alt. 13 mm. 



In color these run from yellowish-white to light cherry. In five 

 specimens only were the revolving lines observed, and these faintly. 

 In general appearance it is quite like the Arkansas mountain forms, 

 bearing a neighborly likeness to albolabris alleni, india?iorum, bin- 

 neyana and edentata. It was collected on the banks of the Kaw 

 river, near Lawrence, Kansas, by W. C. Chadwick, of Cleveland, 

 Ohio, and is named in his honor. 



In the Illinois river valley we have two sizes of multilineata, one in 

 the open bog measuring from 18 to 23 mm. in diameter, the other 

 in wet timber land measuring from 25 to 28 mm. in diameter, well 

 supplied with revolving lines. The smaller size varies in color from 



