STREPTOSTYLA. 149 



not deflexed. Suture but slightly impressed, with a grayish 

 border but no groove. The last whorl tapers to the base, the 

 outlines slightly convex. The aperture is very narrow, but 

 slightly wider near the base. Outer lip slightly arched for- 

 ward below, retracted at the base. The columella bears a 

 very high, white lamella, obscurely bifid or doubled at the 

 base. This lamella continues strong within, and is faintly 

 visible through the last whorl. The whorl is deeply excavated 

 just above the lamella. Length 11, diam. 4.3, length of aper- 

 ture 8.3 mm. 



Northeastern Mexico: Valles, State of San Luis Potosi (A. 

 A. Hinkley) . 



This species is closely related to S. conulus Marts., but so 

 far as the description and figure of that species show, it has 

 not the peculiar sulcus above the columellar lamella which is 

 so prominent in 8. gracilis. The latter also tapers more to- 

 ward the base. 



14. S. OBESA v. Martens. PI. 29, fig. 71, 72. 



Shell oblong-ovate, lightly striatulate, glossy, orange-yellow, 

 unicolored. Suture submarginate, narrowly white. Spire 

 conic, rather acute. Whorls 8|, regularly increasing, slightly 

 convex. Aperture more than half the length of the shell, ob- 

 liquely lanceolate ; the outer margin arching forward below ; 

 columella subvertical, lightly twisted. Length 38, diam. 18, 

 aperture 18x9 mm. (Marts.). 



Honduras (Berlin Museum, one specimen). 



S. obesa MARTS., Biologia, p. 95, pi. 5, f. 12, 12a (May, 

 1891). 



"Nearly allied to 8. turgidula Pfr., but distinctly broader, 

 the diameter equal to the length of the aperture ; coloration 

 more orange, and without darker varices. The suture also in 

 the last whorl is regular, not indented by stoppages of growth, 

 and the white color of the suture itself is more conspicuous" 

 (Marts.). 



15. S. TURGIDULA (Pfr.). Vol. I, p. 46. 



