BULIMULUS-SONORINA. 159 



Bulimus spirifer GABB (in part), Amer. Journ. Conch., iii, p. 236 

 (pi. 16, f. 5 ?) 1867. BINNEY & BLAND, Land and Freshwater Sh. 

 of N. A., i, p. 191, f. 332. Bulimulus (Leptobyrsus) spirifer CROSSE 

 <fc FISCHER, Moll. Terr. Mex., p. 558, pi. 20, f. 26, 27 (exclusive of 

 var. B.). DALL, Proc. U. S. Nat.Mus., xvi, 1893, p. 644, pi. 72, f. 

 8. MABILLE, Bull. Soc. Philomathique de Paris (8), vii, p. 66 

 (1895). FISCHER, Journ. de Conchyl. 1888, p. 318, pi. 13, f. 5. 

 Bulimulus spirifer COOPER, Proc. Cal. Acad. Sci. (2), iii, p. 211. 



Like the other species of this region, there is a wide range of 

 variability in size. The " oily gloss of the surface ' : is noticeable, 

 but its main distinction from the B. inseendens group is in the in- 

 ternal lamina on the axis. In some specimens the terminal portion 

 of this may be seen from the aperture, but usually only the columellar 

 fold proper and not the callous lamina, can be seen without break- 

 ing the shell. The shape of this lamina varies within narrow lim- 

 its, and is well shown in fig. 89. It is lacking in young shells (fig. 

 91) and in all but the last whorl of adults. The narrow lip shown 

 by fig. 87 shows that shell to be immature. 



There can be little doubt that Gabb included two species in his 

 original description, B. spirifer and B. lamellifer ; and the figure 

 may have been drawn from the latter, although if so it was colored 

 according to the real spirifer. This figure, like that on the same 

 plate representing B. vesicalis, is very badly drawn. In the view 

 represented, no prominent columellar fold is visible such as the 

 artist has depicted. Turning to Gabb's typical collection of Lower 

 Californian shells in the Academy collection, we find that he label- 

 led as spirifer the glossy, brown species with regular cork-screw 

 lamina (see fig. 89, drawn from one of Gabb's typical lot). This 

 too, seems to be the form he generally distributed as B. spirifer. 

 His specimens of B. lamellifer were labelled by him " B. xantusi, 

 Binney." It seems, therefore, proper to restrict spirijer to the form 

 generally known under that name, despite the apparent confusion in 

 the original publication. 



Var. orthelasmus n. v. 



Similar to B. spirifer, but very solid and strong, with more con- 

 vex whorls, the lip broadly reflexed and strongly revolute at edge ; 

 internal fold very high and strong, nearly straight and in large part 

 nearly parallel to the axis of the shell, not sinuous or emarginate as 

 in B. lamellifer, or strongly spiral as in B. spirifer ; no spiral sculp- 

 ture visible. Alt. 33*2, diam. 15, alt. of aperture 16 mill. 



