BULIMDLUS-BOSTRYX-LISSOACME. 177 



Aperture slightly oblique, oblong-oval ; peristome simple, unex- 

 pauded, the right margin lightly arcuate, columellar margin dilated, 

 reflexed partly over umbilicus ; columella somewhat straightened, 

 subplicate above. Alt. 19s, diam. 9 mill. ; alt. of aperture 9, width 

 5 mill. (P/V.). 



Hubitnf unknown. 



Bulimus simpliculus PFR., P. Z. S., 1854, p. 124; Monogr., iv, p. 

 490. 







This unfigured species seems to belong to the Chilian group of B. 

 albicans, but it is slenderer than the other described species. 



B. MEJILLONENSIS Pfeiffer. PI. 48, figs. 11, 12, 13, 14. 



Shell narrowly unibilicate, oblong-ovate, solid; opaque-white, with 

 irregular, interrupted corneous streaks, or uniform white. Surface 

 lusterless, with irregular growth-wrinkles (and sometimes showing 

 some faint incised spirals, or coarse malleation). Spire conic, with 

 convex outlines, apex somewhat mamillar, whorls 6, convex. 



Aperture slightly less than half the length of shell, long ovate ; 

 outer lip sharp, with a broad and rather heavy internal thickening. 

 Columella slightly concave, columellar lip dilated ; parietal callus 

 moderately heavy, white. 



Alt. 25, diam. 12 ; aperture 12? mill. long. 



Alt. 22, diam. 10 ; aperture 10 mill. long. 



MejiUones, Chili, on arid hills destitute of vegetation (Phil.) ; 

 Paposo (Paz). 



B. mejillonensis PFR., Malak. Bl., iv, p. 230 (1857) ; Monogr., iv, 

 p. 489 ; vii, 170. PHILIPPI, Reise durch die Wiiste Atacama, p. 

 183, pi. 7, f. 10", b, c. HIDALGO, Viaje al Paoif. Mnl., p. 83. B. 

 callosus PHIL., olim. B. mezilloensisScHAUF., Paetel's Catal., p. 81. 



The internal thickening of the lip is heavier than in allied species. 

 The upper portion of the spire is not so attenuated as in B. affinis, 

 and there is no such excavation of the base of columella as in that 

 species. 



B. AFFINIS Broderip. PI. 48, figs. 8, 9, 10. 



Shell narrowly unibilicate, rather solid or thin, lengthened ovate. 

 Opaque white with interrupted, denticulate corneous streaks, or 

 corneous with white streaks and flecks; slightly shining. Surface 

 with growth-wrinkles, more or less transverse wrinkling or mallea- 

 tion, and in places, traces of spiral incised lines. Spire elevated, 

 12 



