98 THE NAUTILUS. 



distinguished by its size, elevation of spire and striate surface. It 

 occurred in considerable abundance at both localities. 



SOMATOGYRUS HUMEROSTJS, n. sp. PL 5, fig. 2. 



Shell small, subglobular, imperforate, pale green, smooth, shining ; 

 spire prominent, short, sub-conic with a small, obtuse apex. AVhorls 

 3^, roundly shouldered above and flattened toward the suture, body 

 inflated, somewhat flattened on the periphery and at the base ; suture 

 deeply impressed. Aperture large, subcircular, slightly emarginate 

 below. Lip thickened throughout, the callus rounding out to a sharp 

 edge. Columella concave, with a heavy, flat callus which extends 

 from one extremity of the lip to the other, and entirely covers the 

 umbilicus. 



Alt. 4, diam. 3.75 mm. 



Types (No. 22372 Coll. Walker) from the Tennessee River at 

 Florence, Ala. Cotypes in the collection of the Academy of Natural 

 Sciences and A. A. Hinkley. 



The only species to which this can be compared is the S. crassus 

 from the Coosa. It differs, however, in being less solid and more 

 globular, in the heavily shouldered whorls and the flattening of the 

 periphery and base. 



SOMATOGYRUS QUADRATUS, n. sp. PL 5, figs. 3 and 4. 



Shell subglobose, turbinate, imperforate, thick, solid, greenish-yel- 

 low, smooth, except for fine lines of growth. Spire elevated, obtuse, 

 whorls 3^, strongly and roundly shouldered, flattened above and on 

 the sides ; body-whorl large, quadrate, sometimes somewhat swollen 

 above. Aperture rounded but not expanded. Columella with a 

 very heavy, rather narrow, flattened callus which extends over the 

 parietal wall and is separated below the axis from the body-whorl by 

 a deep axial groove. Lip sharp, heavily thickened within ; its inser- 

 tion on the parietal wall is below the periphery. 



Alt. (fig. 3, apex eroded) 4, diam. 3 mm. 



Alt. (fig. 4, apex eroded) 4.25, diam. 3.5 mm. 



Types (No. 22373 Coll. Walker) from the Tennessee River, Flor- 

 ence, Ala. Also Shoal Creek at the same place. Cotypes in the 

 collections of the Academy of Natural Sciences and A. A. Hinkley. 



This species is closely allied to S. georgianus, but differs uniformly 

 in being smaller and imperforate, in the flattened, heavily-shouldered 

 whorls and smaller aperture. As shown by the figures there is con- 



