NO. 1512. PHILIPPINE PLANORBID MOLLVSKS—BARTSCH. 85 



ii point at the aperture, about one-third of the distance toward the 

 peripheiy from the umbilicus to the periphery. The ba«e, like the 

 upper surface, is marked by numerous incremental lines. Aperture 

 decidedly oblique, arrow shaped, the apex falling- at the periphery, 

 and the two barbs above and below the periphery of the preceding- 

 turn. Outer lip thin, somewhat sinuous; basSl lip almost straight; 

 columella exceedingly short, represented by the mere upward turn of 

 the basal lip; parietal wall covered by a thin callus. 



The type has almost five whorls and measures: Altitude, 1.5 mm.; 

 greater diameter, 5 mm.; lesser diameter, 4.4 mm. The type and 

 seven specimens, Cat. No. 192981, U.S.N.M., were collected by Maj. 

 E. A. Mearns in Lake Buluan, Rio Grande Valle}', Mindanao. 



The only other IleHcorhis reported from the islands is P. [IL) 

 luzonteu!< Mollendorfl'. The much larger size — altitude, 3 mm. ; greater 

 diameter, 10.5 mm. ; lesser diameter, 9 mm. — is sufficient to distinguish 

 it from the present species. 



