146 BULIMULUS-ORTHOTOMIUM. 



with irregular pale streaks in harmony with the incremental lines ; 

 the margin of the whorl in front of the suture is also often whitish ; 

 dead shells are waxen or pure white, often with a ferruginous dis- 

 coloration ; whorls five and a half, the nucleus with a central pit or 

 dimple at the apex, the first two turns regularly ribbed with small, 

 sharp, rather distant ribs, the wider interspaces of which are spirally 

 striate; subsequent whorls with close, fine, sharp, somewhat irreg- 

 ular wrinkles, in harmony with the incremental lines, sparse on the 

 last whorl and crossed by fine sharp close striae of variable strength, 

 sometimes hardly visible, but in other specimens distinct and gran- 

 ulating the wrinkles ; all intermediate grades are observable in com- 

 paring many specimens ; suture distinct ; form like that oi pallidior 

 on a smaller scale, varying from moderately wide to slender ; whorls 

 rounded or moderately flattened ; umbilicus small but deeper pro- 

 portionately than in pallidior ; aperture rounded ovate, the lip 

 rather widely reflected, thin, the outer and pillar lips approximat- 

 ing, united by a thin wash of callus. (Dall). 



Alt. 28, diam. 17, alt. of aperture 15 mill. 



Alt. 28$, diam. 15, alt. of aperture 16 mill. 



Alt. 26, diam. 13$, alt. of aperture 13 mill. 



Alt. 25, diam. 16, alt. of aperture 14 mill. 



State of Sonora, N.- W. Mexico, at Ortiz (Bailey), Guaymas (Pal- 

 mer, Gabb), Hermosillo (Eisen), Cerro Tordilla, between Guaymas 

 and San Marcial (Gabb). ? Cape St. Lucas, L. California (W. J. 

 Fisher). 



Bulimulus (Scutalus) Baileyi DALL, Proc. U. S. Nat. Mus., xvi, 

 1893, p. 640, pi. 71, f. 1. STEARNS, Proc. U. S. Nat. Mus., xvii, p. 

 163. COOPER, Proc. Cal. Acad. Sci. (2), iv, p. 139. 



The surface looks smooth to the unaided eye ; the aperture has a 

 very regularly ovate form, the foldless columella concave and pass- 

 ing without angle into the parietal margin. The spiral sculpture 

 mentioned in the description is sometimes wanting entirely. The 

 locality " Cape St. Lucas " is probably incorrect. Ball writes as 

 follows : 



" This species is larger than B. xantusi and the latter is without a 

 reflected lip. B. baileyi has the color of excelsus rather than palli- 

 dior. Its variations, within the limits of its smaller size, are similar 

 to those of pallidior ; the granulation of the surface in the rougher 

 specimens is much finer, but of the same character as that of B. mon- 



