152 VITRINA. 



Y. SOWERBYANA, Pfr. PL 33, figs. 17-19. 



Shell depressed, subauriform, arcnately plicatulate, very thin, 

 pellucid, reddish brown ; suture deeply impressed ; whorls 3, the 

 last depressed, flattened above, the periphery angulated, the base 

 convex ; aperture large, oblique. Innately oval, the columellar 

 margin narrowly membranaceous. Diam. 22, alt. 11 mill. 



W. Africa. 

 Y. GOMESIANA, Morelet. PL 33, iigs. 20-22. 



More lenticular, the body-whorl not so obliquely flattened 

 above, and less convex below than. in V. Sowerbyana, the whorls 

 also less rapidly enlarging, and the color more yellowish. 



Diam. 20, alt. 8 mill. Angola, W. Africa. 



Y. AMCENA, Morelet. PL 33, figs. 23, 24. 



Shell much depressed and striate above, more convex, smooth 

 and shining below, compressed at the periphery, suture im- 

 pressed, lightly but distinctly marginate ; yellowish with a broad 

 chestnut fascia on the upper surface ; columellar lip widely 

 membranaceous-margined. Diam. 25, alt. 9 mill. 



Angola, W. Africa. 

 Y. GRANDIS, Beck. PL 33, figs. 25-27. 



Rather thin, lightly radiately plicatulate, diaphanous, not 

 shining ; yellowish white ; whorls 3J, moderately enlarging, sub- 

 planate, the last depressed, periphery obsoletely angulated, base 



wide, striatulate, shining. Diam. 18, alt. 8 mill. 



Senegal. 



Helicophanta formosa, Jonas (in litt.) is quoted as a synonym 

 by Pfeiffer. The specific name is singularly inappropriate, in 

 view of the giant forms which have been characterized since its 

 publication. 



Y. SIGARETINA, Recluz. PL 33, figs. 28-30. 



Shell almost plane above, thin, with arcuate striae, shining, 

 pellucid, yellowish green, suture lightly impressed ; whorls less 

 than 3, rapidly enlarging, the body-whorl depressed, not angu- 

 lated, a little more convex below where it is membraneous 

 margined ; aperture oblique, transverse, oval-lunate, the colu- 

 mellar lip receding, arcuate. Diam. 16, alt. 7 mill. 



Sedion, Casamanza River, Senegambia. 



