364 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



The present species belongs to the group which has the malleations 

 on the last whorl extending to the peristome. The only other known 

 member with this character in the general region is Obba planulala 

 salcedoi, a much smaller race from Ilin Island. 



OBBA PLANULATA SALCEDOI, new subspecies 



Plate 92, Figure 3 



The shell is lenticular, the last whorl rather acutely angulated 

 at the periphery. The nuclear whorls and the ground color of the 

 postnuclear whorls are flesh-colored. The postnuclear whorls are 

 marked by streaks and blotches of pale brown, and the median spiral 

 band of brown, which extends almost to the peristome. The base is 

 of flesh-colored ground color; the posterior half has the pits of the 

 malleations brown; the peristome is soiled buff and the interior of 

 the outer lip pale brown. The nuclear whorls are marked by fine 

 incremental lines and microscopic spiral striations. The early post- 

 nuclear whorls are acutely angulated, the succeeding turns falling 

 below the angle. The first and second postnuclear whorls are malie- 

 ated on the anterior half; the last one is strongly malleated almost 

 over its entire surface, only the portion immediately below the summit 

 being free of these strong hammer marks. The base is moderately 

 rounded and also malleated on its posterior half. In addition to the 

 malleations, the postnuclear whorls are marked by not strong but 

 irregular incremental lines and very fine spiral striations, likewise 

 fine crisscross lines, which cut the incremental lines and spiral sculp- 

 ture obliquely. These crisscross lines are strongly marked on the upper 

 surface of the last whorl. The aperture is rather small, broadly 

 oval; the peristome is reflected and thickened and covers about one- 

 third of the umbilicus. 



Type.— The type, U.S.N.M. No. 382891, comes from Ilin Island, 

 south of Mindoro. It has 4.5 whorls, and measures: Height, 11.8 

 mm; greater diameter, 27.3 mm; lesser diameter, 23 mm. 



Remarks. — The large extent of the malleations distinguishes this 

 subspecies from all the others. 



OBBA PLANULATA BONGABONA, new subspecies 



Plate 92, Figure 2 



The shell is almost lenticular, the whorls being decidedly keeled; 

 the succeeding ones falling below this keel to which they are appressed 

 gives them a somewhat overhanging aspect. The last whorl is acutely 

 keeled at the beginning, and quite strongly angulated behind the peri- 

 stome. The first nuclear whorl is flesh-colored, the rest buff. The 

 postnuclear whorls are flesh-colored, blotched, streaked, and vermicu- 

 lated with brown on the upper surface. A narrow median, more or 

 less interrupted brown band, is present, but evanesces on the last half 



