132 OXYSTYLA, SOUTH AMERICAN. 



clouded with lighter, and with wide, ill-defined, bluish or olive-green 

 streaks behind the extremely narrow blackish varices; entire last whorl 

 sometimes without light flames or stripes. Varices narrow, two or 

 three on the last whorl, one or two above it. Surface with fine, 

 irregular spiral strias and some shallow coarser furrows, somewhat, 

 but finely, malleated ; plicate below the sutures, and sometimes shal- 

 lowly so on the body whorl generally. Whorls 6 j, slightly convex. 



Aperture oblique, pure white or purple-tinted inside, often showing 

 dark stripes at the positions of the varices ; peristome obtuse, unex- 

 panded, olivaceous-bordered outside, with a blackish border within, 

 shading into violaceous. Parietal callus strong, black ; columella 

 heavy, vertical, straight, truncate or subtruncate at base, white or 

 white-edged. 



Alt. 67, diam. 38, longest axis of aperture 36 mill. 



Alt. 63, diam. 37, longest axis of aperture 34^ mill. 



Alt. 57^, diam. 3H, longest axis of aperture 31 mill. 



Habitat unknown. 



Orthalicus decolor STREBEL, Beitr. Mex. Land- und Susswasser- 

 Conch. v, p. 37, pi. 7, f. 2, 3, 4 (1882). 



One of Strebel's specimens was labeled "Bulimus mars, Costa 

 Rica." Those in the collection of the Academy have borne the same 

 specific name, with the localities " Ecuador " and " Brazil;" but I 

 attach no weight whatever to these data. Similar to 0. mars in 

 general features, this species differs markedly in the straight, vertical 

 columella, without a fold above. 0. ponderosa I have not seen, and 

 it is not unlikely that decolor may prove to be a form of that species. 

 The differences do not seem to be great. 



South American Species. 



A. Longest axis of aperture exceeding half the length of the shell; 

 columella concave or straight. 



b. Ventricose, with pairs of yellow lines forming large zig- 

 zags; whorls 5^r ; alt. 5057 mill. bifulgurata, ^. 143 

 b l . Ovate-conic, uniform whitish or with three bands, no lon- 

 gitudinal flames. maracaibensis form imitator, p. 140 

 5 2 . With longitudinal flames. 



c. Large, alt. 56-68 mill., with inflated body-whorl ; 

 spire flamed, the last whorl brown with obscure or 

 sub-obsolete flammulation, spiral bands inconspicu- 



