BULIMULUS-ORTHOTOMIUM. 147 



tezuma. The species was at first confounded with B. xantusi, the type 

 of which had been mislaid, but when the latter was found and a 

 series compared, it was obvious that they belonged to different sec- 

 tions of the genus. It is named in honor of Mr. Vernon Bailey, of 

 the U. S. Department of Agriculture, who collected it in western 

 Mexico." 



This is the only known species of the mainland except excelsus, 

 which is very closely allied to the Peninsular group, unless the 

 Mexican record of sufflatus proves correct. 



B. GABBI Crosse & Fischer. PI. 19, figs. 58, 59 ; pi. 33, fig. 34, 35. 



Shell umbilicate, ovate-conic, thin; white under a thin, light 

 brown cuticle. Sculpture of irregular longitudinal wrinkles, and 

 close, unequally spaced spiral series of short, rounded granules, situ- 

 ated upon the wrinkles. Spire conic, the apex obtuse, two nepionic 

 whorls well rounded, sculptured with delicate vertical riblets ; whorls 

 5* to 6, convex, rapidly increasing, separated by deep sutures. 



Aperture large, ovate, varying from nearly half to over half the 

 total length of shell; peristome thin, outer lip scarcely expanded; 

 columellar lip broadly dilated above ; columella concave below, 

 straight or concave above, with no fold. 



Ait. 24, diarn. 14 ; alt. of aperture 12 J mill. 



Alt. 23, diam. 12 ; alt. of aperture 10s mill. 



Lower California (Gabb). 



Bulimulus (Scutalus') gabbi CROSSE & FISCHER, Journ. de Con- 

 chyl., xx, 1872, p. 223 ; Moll. Mex., p. 517, pi. 20, f. 19. COOPER, 

 Proc. Cal. Acad. (2), iii, p. 214, 340 (as probable var. of xantusi). 



A decidedly more conic species than B. xantusi with larger aper- 

 ture, different sculpture and nucleus. In B. xantusi the first whorl 

 is subangular above, with well excavated apical pit, approaching the 

 form seen in B. inseendens, and the vertical riblets thereon are fine 

 and close ; in B. gabbi the earliest whorl is well rounded, with 

 moderate axial pit, as in B. baileyi, and the delicate costulse are 

 much more separated. On the last whorl the granules are every- 

 where small and rounded, much less coarse and irregular than in 

 xantusi. 



B. gabbi is considerably like the more granular form of B. baileyi, 

 but lacks the conspicuously expanded lip of that species. It has 

 been united with B. xantusi by Dall and Cooper, but apparently 

 without comparison of typical examples of gabbi. Having before 



