THE NAUTILUS. 51 



S. wheeleri Walker. Apical whorl small, very much elevated, 

 more so than in any other species, closely coiled, very convex, 

 greatly constricted by the suture, much everted and obliquely 

 flattened above. Sculpture, very strongly spirally punctate on 

 the first half of the whorl, becoming punctate-lirate above on 

 the second half, lirate below. 



The examination of the material from Arkansas collected by 

 Messrs. Hinkley and Wheeler furnished the following forms, 

 which seem to be new. 



SOMATOGYRUS WHEELERI, n. sp. Figs. 1 and 2. 



Shell turbinate, umbilicate, rather thick and solid, greenish- 

 horn color, smooth, with fine, regular, distinct lines of growth. 

 Spire prominent, elevated, subturreted and rapidly acuminating 

 to the apex. Apical whorl small, much elevated, closely coiled, 



FIG. 1. SOMATOGYRUS WHEELERI. FIG. 2. APEX OF SAME. 



very convex and much constricted by the suture, much everted 

 and obliquely flattened above, tip immersed: the first half of 

 the whorl is very strongly spirally punctate, becoming punctate- 

 lirate on the second half and lirate below. The second whorl 

 is less convex and the suture below it is less impressed ; as it 

 passes into the third whorl it tends to become more or less 

 shouldered. The third whorl is roundly shouldered above and 

 distinctly flattened below the shoulder. The body-whorl is 

 large, strongly shouldered, obliquely flattened above the shoul- 

 der with a distinct groove between it and the suture, distinctly 

 flattened peripherally and rather rapidly rounding into the um- 

 bilicus. Aperture large, outer lip obliquely flattened and some- 

 what concave above the angle formed by the shoulder, from 

 which it curves regularly to the columella. Columella narrow 

 and oblique, adnate for only a short distance on the parietal 



