128 OXYSTYLA, MEXICO, ETC. 



The specimens before rne show several striking divergencies from 

 the above. In one lot from the Isthmus of Tehuantepec the short, 

 concave columella is black-brown throughout, the shell long and 

 narrow. Some of them (pi. 22, fig. 2) are white, with widely sepa- 

 rated grayish-purple streaks, extending neither to suture or base; 

 some of the varices edged with rust-brown. In others (pi. 21, fig. 

 33) the streaks are somewhat better developed, with some bright 

 chestnut ones intermingled, and considerable suffusion of chestnut 

 on the latter part of the last whorl. Sometimes a narrow band ap- 

 pears just above the suture on some whorls of the spire. Suture 

 white-bordered below. In all this lot the earlier 3 whorls are white, 

 without dark apical spot. The specimen figured by Crosse and Fischer 

 (pi. 22, fig. 1) is similar to the Tehuantepec shells, though rather 

 more closely streaked, and with white columella. 



Another series of three shells (pi. 22, fig. 6), also white at the 

 apex, has wide, waved grayish-purple flames shading into reddish on 

 one edge ; the columella is light-edged and folded, and the surface 

 shows rather strong and regular folds. The largest one is shown in 

 the figure. Alt. 68, diam. 37, longest axis of aperture 34 mill. 



Var. strebeli n. v. (pi. 22, figs. 7, 8, 9). Shell short, conic, solid, 

 with sub-regular fold-like growth-wrinkles ; white, with some brown 

 flames or traces of them on the spire, sometimes a few narrow, straight 

 ones on the body-whorl, and with several very narrow varices; apical 

 one or two whorls dark ; oolumella passing gradually into the parietal 

 wall, and obliquely truncate at base, white or brown with white edge; 

 parietal wall light or dark brown. 



Alt. 47, diam. 30, longest axis of aperture 28-J mill. 



Alt. 46, diam. 27^, longest axis of aperture 26 mill. 



Var. boucardi (Pfeiffer). PI. 20, figs. 20-26, 29. 



The type of 0. boucardi is represented by fig. 26 of plate 20. It 

 is white with broad brown bands and black varices, the suture white- 

 bordered below. Other forms, in which the white predominates, and 

 the stripes are reduced, sometimes very widely separated, seldom 

 bent in zigzag, and often shortened into mere spots, as in figs. 20, 21, 

 24, 25, are also referred to this variety. Another of its manifesta- 

 tions is the " form A" of Strebel, in which the stripes are very broad 

 in the young and on the spires of adults (pi. 20, figs. 23, 29). On 

 the whole, the bands are more vivid than in 0. longa. The apex is 

 generally white. 



