350 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



OBBA LISTERI MAYABIGANA, new subspecies 



Plate 89, Figure 1 



The shell is rather large, depressed-helicoid, and acutely keeled at 

 the periphery. The nuclear whorls are of soiled flesh-color. The 

 ground color of the rest of the shell is also of this tint, but tinged with 

 buff. In addition to this, the upper surface of the whorls is variegated 

 and blotched and spotted with brown, among which the ground color 

 appears more or less in the shape of figurations. There is a supra- 

 median interrupted line of brown. The base is pale yellow with an 

 interrupted band of brown about one-third of the distance between 

 the periphery and the umbilicus anterior to the periphery. The 

 malleations between this brown band and the periphery are of a paler 

 shade of brown. The peristome is soiled white, and the interior of the 

 aperture is brown with a purplish tinge. The nuclear whorls are 

 marked with fine incremental lines and microscopic spiral striations. 

 The postnuclear whorls are strongly malleated, the malleations ex- 

 tending to the summit. In addition to this, they are marked by strong 

 incremental lines and fine crisscross sculpture, which is best shown 

 behind the aperture of the last turn. The base is marked by the con- 

 tinuation of the incremental lines and rather strong malleations, which 

 extend about halfway between the periphery and the umbilicus, the 

 umbilical portion being marked by incised spiral lines. The aperture is 

 irregularly oval; the peristome is expanded and reflected, covering about 

 one-third the umbilicus. The inner lip bears a conspicuous tooth. 



Type.— The type, U.S.N.M. No. 322930, was collected by Pedro de 

 Mesa at Mayabig, Baco, Mindoro. It has 4.9 whorls, and measures: 

 Height, 13 mm; greater diameter, 33.3 mm; lesser diameter, 26.4 mm. 



Remarks.— Thirteen topotypes, U.S.N.M. No. 382931, yield the 

 following measurements: 



