358 MEXICAN BOUNDARY SHELLS— DALL. 



funicular dimple; whorls moderately rounded, the last much the largest, 

 the spire obtusely conical; base full and rounded, with a rather large, 

 deep, and subcylindrical umbilicus; outer lii) sharp, hardly reflected; 

 l)illar lip reflected rather widely near the body around (not over) the 

 umbilicus; body with a thin wash of callus, the outer lip strongly 

 incurved at its jnnction, giving a somewhat tubular look to the suture; 

 substance of the shell thin, without markings. Length 18, of the last 

 whorl 13, maximum diameter II mm. 



Summit of Black Mountain, Sonora, Mexico; Dr. Mearns. No. 129993, 

 U.S.N.M. 



The shells above described are not in the best condition, and I have 

 some hesitation in describing them; but after an exhaustive compari- 

 son with the Bulimuli of the region and of Lower California I find 

 none to which the present form can be confidently assigned. It recalls 

 somewhat B. a-antusi, Binney, and B. haileyi, Dall, but is smaller and 

 more globose than either. In form some of the varieties of 7>. alfernatiis, 

 Say, come nearest to it, but have a different surface and nuirkiugs 

 which are absent from the present form, and none of them has so deep 

 and cylindrical an umbilicus. I have thought it best, therefore, to put 

 it on record until the reception of more material shall enable a final 

 decision to be made. 



BULIMULUS (ORTHOTOMIUM) COOPERI, Dall. 



BuUmnlus piliila (Crosse and Fischer), Cooper, Proc. Cal. Acail. Sci., Ill, pp. 



209, 340, pi. V, fig. 12, 1894. 

 Bulimulits cooperi, Dall, Proc. U. S. Nat. Mus., XVIII, p. 5, 1895. 



The specimen figured as pilnla.i from San Jose del Cabo, by Dr. 

 Cooper, is B. pilula., Crosse and Fischer, but not of Binney. The 

 former, judging from their figure and from somewhat weathered speci- 

 mens, has a peripheral band or bands, in Avhich two darker bound a 

 central paler zone; the surface has well-marked incremental lines, but 

 no spiral striiTB or granulations. It has been well figured by Crosse 

 and Fischer and Cooper, though the latter does not show the bands, 

 his specimens being bleached. There can be no doubt that this species 

 is distinct from the original and only true B. pilula^ and, since it does 

 not seem to have been named, I have proposed for it the name of Buli- 

 mulus cooperi. 



BULIMULUS (ORTHOTOMIUM) DECIPIENS, Cooper. 



Bitlimulus decipiens, Cooper, Proc. Cal. Acad. Sci., 2 ser., V, p. 164, June, 1895. 



A third species was among these referred at first to B. pilula, with 

 some doubt, by Dr. Cooper in the series submitted to me. Unfortu- 

 nately, the specimens, though living when obtained, are not adult. 

 They appear, however, to represent a very distinct species. The shell 

 is of pale, livid, i)inkish brown, with a i>erii)heral, narrow, pale-yellow 

 baud. The largest specimen has a Leptobijrsus nucleus (not keeled) of 



