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This genus, together with the others comprising the subfamily, 

 is of South American origin. In the northern part of that con- 

 tinent, the species are numerous, but one only inhabits the West 

 Indies and the circumjacent North American coast. The 

 Orthalicus zebra, distinguislied by all Ameiican authors from 

 the undatua, is scarcely even a variety of it, "while the true 0. 

 zebra of Miiller, a very different shell, inhabits the western 

 parts of South America. 



1. Orthalicus undatus, Ferussac. 



Plate 13, figures 1, 2, 3. 



Shell subconical, striated by growth lines, thick ; spire ele- 

 vated, suture moderate, slightly crenated ; wliorls 6, convex, 

 the last about two-thirds of the total length of the shell ; 

 aperture large, ovate. White, with longitudinal undulated or 

 zig-zng chocolate-colored flames, intersected by three narrow 

 revolving lines of the same color ; inner surface marked the 

 same as the external. 



Length 45, diam. 27 mill. CoXirYTdM'. 

 Southern Florida. 



BULIMULIN^. 



All the genera of this subfamily are of South American origin, 

 and only a few species of them extend into the subjacent parts 

 of North America. 



1. Drym^us, Albers. Elongate-conical, perforate or rimate, 



thin, diaphanous, variegated ; aperture large, oblong ovate, 

 columella more or less twisted, peristome thin, expanded, 

 columellar margin reflexed. 



2. LiosTRACUS, Albers. Oblong-conical, perforate, thin, 

 smooth, fasciate ; aperture obliquely semi-oval, lip thin, 

 more or less expanded, the columellar margin dilated, 

 reflexed.. 



