14 THE NAL'TILU.S, 



A NEW SONORELLA FROM ARIZONA. 



BY S. S. BERKY. 



Mr. Cieorge Willett ha? sent in specimens of a Sonorella irom 

 Gila County, Arizona, which do not seem referahle to any of the 

 described species. A diagnosis is accordingly offered below. 



SONOKELLA ROOSEVELTIANA new SpecieS. 



The shell is depressed. In the type the spire is low conoidal, 

 but in some specimens is higher, while in others is raised but 

 little above the level of the principal whorl ; umbilicate, the 

 umbilicus contained about eight times in the major diameter ; 

 very thin and fragile, ^\'horls 4^ to 4^. Embryonic whorls a 

 little less then H, the initial half-whorl very finely, irregularly, 

 radially, wrinkled-costulate, the wrinkles becoming finer and 

 more wavy in the following whorl, where the}' are crossed by 

 a series of fine, delicate, raised lines, passing obliquely down- 

 ward and forward from the summit of the whorl to the suture, 

 the sculpturing sometimes showing with beautiful regularity 

 over most of the whorl. Yet when a series of shells is examined 

 the finer sculpturing shows great variation. Frequently the 

 incised lines are more or less interrupted, especially near the 

 summit, into elongate papillae which later coalesce. Some- 

 times lines or papillae are evident running in a direction counter 

 to those just described and intersecting them. Above the sum- 

 mit, where the wrinkly lines of growth come closer together, 

 the appearance is more granular and less distinct, but occasional 

 traces of similar lines apparentl}' pass obliquely downward 

 (actually upward on account of the depression of the whorl at 

 the suture) and backward from the superior suture to the sum- 

 mit. In most of the specimens the fine wrinkling becomes al- 

 most granulose. The next whorl-and-three-quarters show irre- 

 gular growth-lines crossed obliqueh' by lines of minute papillae, 

 though I can make out no bristles with the aid of such magni- 

 fying power as happens to be b}' me. The last whorl is appar- 

 ently smooth except for the lines of growth. This whorl is 

 moderately wide and descends slightly in front. The aperture 



