276 Bulletin American Museum of Natural History [Vol. LIII 
4. Minute sculpture of dense granulation, like pebbled leather, and faint, indistinct 
spiral lines; form biconic, the periphery angular. 
P. alutacea Pilsbry and Bequaert. 
Minute sculpture of fine axial wrinkles decussated or cut into oblong beads by 
impressed spirals; generally irregularly and locally developed.......... 5. 
Minute sculpture of faint lines of growth only; a very slight peripheral angula- 
HOM LAURE ny, WAST DIGG ek os Rts GW ara VL nee Ca tap le P. ignobilis (J. Thiele). 
Dy Pempnery eneuler Or Mar KecoWy a 1OW COlIer Ui c ese Bese ois ae ee ee 6. 
UP ere iy (MOUMNCG ae At hats enti ieahl: Tataes ee P. liricincta major (J. Thiele). 
6. Last whorl decidedly more swollen than those of the spire. 
P. ponthiervillensis mut. spoliata (Dupuis and Putzeys). 
P. superba mut. inculta Pilsbry and Bequaert. 
Last whorl not swollen, the shell tapering slowly and regularly; periphery 
BO GPa Mert Ma Need ike een P. mungwana Pilsbry and Bequaert. 
7. A few very weakly raised, mostly blunt spirals, none around the columella; 
last whorl rather swollen, strongly convex. 
P. ponthiervillensis mut. spoliata (Dupuis and Putzeys). 
P. superba mut. inculta Pilsbry and Bequaert. 
7-9 smooth, clean cut spiral cords, or if fewer there are plain zones below suture 
Sl Wer teh) ainest remr Mots eee Ce Stee tome Or el... 8. 
a> Strole Spiral cords or Carine Gn lash whorl, oi O ete eel... 10. 
8. Upper spiral forming a horizontal shoulder below the suture; in all 7-8 spirals 
on the last whorl; large shells of stout figure. 
P. medjeorum Pilsbry and Béquaert. 
Whorls regularly convex, the upper spiral not prominent; contour graceful. .9 
9. Having spirals throughout, or with plain zones below suture and periphery. 
3 P. liricincta (KE. A. Smith). 
Sunilar, but without spiral cords around the columella. 
P. pokoensis Pilsbry and Bequaert. 
10. Spiral cords squamose-tubercular....P. ponthiervillensis (Dupuis and Putzeys). 
Spirals smooth, or only the basal éaberoulat Soy AEE Gan 67) rae wkd. 
11. ‘Two very strong and two or three weaker keels on last whorl; 35X15 mm. 
P. tornata (E. v. Martens). 
ee very strong keels on the last whorl, the lowest often waved, usually a weak 
fifth cord around the columella; size larger. 
P. superba Pilsbry and Bequaert. 
Potadoma graptoconus, new species 
Plate XX, Figures 10 and 11 
Ganda Sundi (type locality) and Lukula (H. Schouteden Coll.). 
We have also seen specimens from the basin of the Niari, in the French 
Congo (Le Chatelier Coll.). 
The shell is solid, resembling P. freethit (Gray) in shape. It is cinnamon-brown, 
lighter on the spire, or between that hue and honey-yellow, not glossy, with micro- 
scopic sculpture of fine, close, minutely rippled spiral strie, and around the columella 
a group of about 4 small cords. .The whorls are nearly flat, the penult becoming 
slightly convex, the last convex at and below the periphery. The aperture is ovate, a 
