160 BULIMULUS-SONORINA. 



Based upon a specimen which has lost its cuticle and color. The 

 exact locality is unknown, hut it differs remarkably from B. spirifer, 

 its nearest ally, in the great solidity and the shape of the lamina. 



B. LAMELLIFER Pilsbry. PI. 21, figs. 94, 95, 96, 97, 98, 99. 



Shell deeply rimate, oblong-conic, rather thin, white, sometimes 

 rather translucent. Surface less glossy than in B. spirifer, smooth- 

 ish, under the lens seen to be finely striated, the striae cut into long 

 granules by spiral lines (fig. 99). Whorls 62, convex, the last some- 

 what swollen below ; sutures impressed. 



Aperture large, ovate ; peristome very broadly expanded and re- 

 flexed, white, the terminations approaching, joined by a short, thin 

 or heavy callous. Columella dilated above, folded ; and from the 

 aperture may be seen a sharp, high, twisted lamina, which within 

 the last whorl (figs. 94, 96) rises into a very high, thin, square or 

 emarginate, erect plate, very noticeably obstructing the cavity. 



Alt. 34, diam. 17 ; alt. of aperture 19 mill. 



Alt. 33 J, diam. 15* ; alt. of aperture 15 J mill. 



Alt. 32, diam. 15; alt. of aperture 15 mill. 



Alt. 23?, diam. 10 ; alt. of aperture lOf mill. 



Lower California (W. M. Gabb), probably on the Gulf side be- 

 tween San Antonio and San Borja. 



Bulimulus lamellifer PILSBRY, Nautilus, x, p. 103, January, 1897, 

 ? Bulimus spirifer GABB, in part. ? Bulimulus spirifer var. B. 

 CROSSE & FISCHER, Moll. Terr. Mex., p. 558. 



The square, erect plate within the last whorl is a constant differ- 

 ence between this species and B. spirifer. B. lamellifer is also white 

 instead of corneous brown, less glossy and more distinctly granulose 

 than the other species, on the average smaller, and generally more 

 of the internal lamina may be seen without breaking the shell. 

 Gabb seems to have confused the larger specimens with B. npirifer, 

 the smaller with B. xantusi. Seventeen examples examined. 



B. VESEYIANUS Dall. PL 21, figs. 92, 93 (enlarged). 



Shell stout, inflated, brownish, polished, with seven whorls ; suture 

 appressed, distinct, but shallow ; nucleus worn in all the speci- 

 mens but apparently not differing from that of B. Bryanti, except 

 as being more blunt ; whorls, except the last, rather rounded, the 

 last whorl somewhat flattened at the periphery ; umbilicus large but 

 narrow, overshadowed by a very wide expansion of the pillar-lip ; 



