70 OLTVELLA. 



With this I unite 0. pulla, Marr. (fig. 19), 0. versicolor, Marr. 

 (figs. 20, 21), 0. compta, Marr. (fig. 22)". 0. Capensis, Sowb. (fig. 

 23), said to come from the Cape of Good Hope, can only be 

 separated by its doubtful locality. 



0. PUELCHANA, d'Orbigny. PI. 16, figs. 24, 25 ; PI. 1, fig. 1. 



Yiolet-brown, more or less maculated, with a narrow white 

 band above the brown-tinted fasciole, and a wider band, macu- 

 lated with brown, below the suture ; aperture dark-colored 

 within. Length, 12-15 mill. 



San Bias, Patagonia (d'Orb) ; Garthagena, Centr. Am.? (Reeve). 



I fear that this is no more than an extreme color-variety of 

 the preceding species. 0. cyanea, Reeve, is a synonym, not 

 differing in any respect. 



0. UNDATELLA, Lam. PL 16, fig. 18 ; PL 17, figs. 35-38 ; PL 33, 



fig. 31. 



Ash-gray, with zigzag chestnut markings, distinct or obsolete, 

 but forming two well-marked revolving bands by the color 

 becoming more emphasized ; a yellow band marked with chestnut 

 beneath the sutures ; fasciole yellowish, strigated with chestnut ; 

 interior and base of columella chocolate-colored. 



Length, -5-'8 inch. 



Panama t-> Mazatlan. 



The above description is that of the typical coloration, but the 

 variation in color and markings is so great that it is wonderful 

 that a number of species have not been separated from it. One 

 of the principal variations is a pure white, with indefinite 

 cloudings, maculations or zigzags of chocolate ; another white, 

 with pink longitudinal zigzag markings, etc. Fig. 31 represents 

 0. nedulina, Duclos, 



0. GRACILIS, Brod. and Sowb. PL 16, fig. 26 ; PL 17, fig. 27. 



Shell rather slender, with elevated spire, and somewhat effuse 

 below ; yellowish fawn, with light chestnut zigzag markings and 



maculations. Length, *7-'9 inch. 



Mazatlan; Lower California. 



Distinguished from 0. Anazora, which inhabits the same 

 region, by its more slender form, elevated spire, greater size and 

 lighter color. 0. tennis, Marrat (fig. 27), is probably a juvenile 

 of this species. 



