VITRINA. 153 



Y. ANGOLENSIS, Morelet. PI. 33, figs. 31-33. 



Depressed globose, thin, subrugulose, radiately plicatulate at 

 the suture, diaphanous, scarcely shining, brownish yellow; spire 

 conoidally depressed, suture margined ; whorls scarcely 4, the 

 last depressed rounded, shining below ; aperture oblique, lunately- 

 rounded, the columellar margin very shortly reflected at its 

 insertion, forming a narrow slit. Diam. 17, alt. 9 mill. 



Angola. 

 Y. CORNEOLA, Morelet. PL 33, figs. 34-36. 



Depressed globose, thin, inconspicuously striate, not shining, 

 diaphanous, orange-brown ; spire depress^d-conoidal, suture very 

 narrowly margined ; whorls 3-J-, the last lightly compressed at the 

 periphery ; aperture oblique, lunately-rounded, columellar margin 

 very narrowly dilated and reflected at its insertion. 



Diam. 8, alt. 4 mill. 



Angola, W. Africa. 

 Y. DUMETICOLA, Dohrn. PL 33, figs. 37-39. 



Depressed globose, very thin, lightly striate, very shining, 

 vitreous horn-color; whorls 3, rapidly enlarging, the last rounded, 

 slightly more convex below ; aperture oblique, Innately rounded, 

 partly showing the whorls. Diam. 9, alt. 5'75 mill. 



Prince's Isl., Gulf of Guinea. 



IV. East and South African Species. 



Y. SENNAARIENSIS, Pfr. PL 33, figs. 40-42. 



Turbinatety depressed, thin, obliquety rugosely striate, some- 

 what shining, pellucid, corneous-green, usually dark stained; 

 spire subturbinate, mucronate, suture deeply impressed ; whorls 

 3, convex, the last obliquely flattened, and obsoletely angulate 

 on the periphery ; lip thin, subinflected above. 



Diam. 6-6, alt. 3 mill. 



Sennaar, Nubia. 

 Y. DARNAUDI, Pfr. PL 33, figs. 43, 44. 



Depressed globose, rather thin, irregularly striulate, somewhat 

 shining, light greenish corneous ; spire convex, obtuse, suture 

 narrowly margined; whorls scarcely 3, convex, rapidly enlarging; 



