142 BULIMULUS-ORTHOTOMIUM. 



Most nearly allied to B. pallidior, but larger with the whorls less 

 convex, especially above. 



Dall writes: "This is the largest, finest, and most local of the 

 forms of this group, when fresh is streaked with waxen-white and 

 purplish-brown and is whitish in front of the suture. It has two 

 nuclear whorls obtusely keeled and with a less conspicuous apical 

 pit than the others. The spiral strhe on the nucleus are often ex- 

 tremely faint, but can usually be made out with a magnifier on the 

 later whorls, I have not seen any specimens where the striation was 

 strong enough to granulate the wrinkles. While differing somewhat 

 in form, the size is rather uniform compared with that of the other 

 species as might be expected from its smaller range in area and 

 altitude. The pillar bears an observable fold but no lamina." 



Figure 71 represents Gould's type. The shells collected by Gabb 

 at Siualoa (figs. 69, 70) are decidedly larger, and show spiral series 

 of fine long granules on the spire, subobsolete on the body whorl. 

 This large form may be distinguished as var. sinaloce. 



B. PALLIDIOR (Sowerby). PL 19, figs. 49, 51, 53, 54, 55. 



Shell oblong-turrited, very deeply rimate, the umbilical region 

 excavated ; white or cream-white ; surface shining, faintly wrinkled 

 by growth-strise, and with subobsolete spiral series of oblong gran- 

 ules, often hardly visible. Spire slender, high-conic, the apex obtuse. 

 Whorls 6 to 7, convex, the nepionic costellate, the last whorl more 

 convex at the shoulder ; sutures impressed, generally accompanied 

 by an impressed line below producing a narrow margin. 



Aperture oblong, the peristome expanded, flaring below, broadly 

 dilated and reflexed on the columellar margin. Columella concave 

 below, straighter above, usually showing a deep-seated wide fold. 

 Parietal callus light. 



Alt. 37, diam. 19 J, alt. of aperture 20 mill. 



Alt. 39, diam. 2H, alt. of aperture 20 mill. 



Lower California, chiefly southern ; San Jose del Cabo (Belding, 

 Eisen) ; Cape St. Lucas (Xantus) ; Punta Arena (Bryant) ; Carmen 

 Island (Stearns) ; Santa Margarita Island (U. S. Fish Commission). 



Bulinus pallidior SOWB., P. Z. S., 1833, p. 72 ; Conch. Illustr., f. 

 39, 44. Bulimus pallidior DESK, in Lam., An. s. Vert., viii, p. 280. 

 PFR., Monogr., ii, p. 61 ; vi, p. 40. REEVE, Conch. Icon., pi. 55, 

 f. 365. W. G. BINN., Proc. Acad. N. S. Phila., 1861, p. 331. 

 Bulimulus pallidior BECK, Index, p. 66. H. FISCHER, Journal de 



