NEW LAND SHELLS FROM THE PHILIPPINE ISLANDS. 



By Paul Bartsch, 



Assistant Curator Division of MollusJcs, United States National Miiseum.. 



The United States National Museum has recently received an 

 extremely interesting collection of land shells from the Hon. Dean C. 

 Worcester, secretary of the interior of the Philippine Islands. The 

 shells were collected by him on two small and little- visited islands, 

 Calusa, the westernmost of the Cagayanes Islands, and Olanivan, the 

 northern of the Sarangani group off southeastern !^Iindanao. 



The three species in the lot are all new; their affinity will be dis- 

 cussed under each species, descriptions of which follow. 



OBBA WORCESTERI, new species. 

 Plate 43, figs. 1-3. 



Shell lenticular, marked by decidedly retractive lines of growth and 

 very fine, closely spaced spiral striations, excepting the first whorl 

 (the nucleus), which is smooth. The following whorl is light horn- 

 yellow; the succeeding turn gradually darkens to chocolate brown 

 On the third whorl three spiral bands of chocolate brown become 

 apparent, which eventually cover more of the space between the 

 sutures and the periphery than the buff flushed areas that separate 

 them. The middle one of these three bands is the darkest and 

 widest and occupies the middle of the whorls between the sutures. 

 The posterior band is separated from the summit by a very narrow 

 light zone; the spaces separating the median from the anterior and 

 posterior bands are of equal width and as wide as the median dark 

 zone. Periphery strongly keeled. Base moderately broadly umbili- 

 cated; marked by two brown bands, the first of which, the narrower, 

 is separated from the periphery by a very narrow light line; the sec- 

 ond, which equals the median band of the spire in width, is a little 

 farther anterior to the other band than its own width. The light 

 zone separating these two bands and the rest of the base, yellow with 

 a greenish flush. Aperture suboval, somewhat angulated at the 

 junction of the superior and basal lip; the angle corresponding to 

 the peripheral keel; peristome thickened and reflected; basal lip 



Proceedings U. S. National Museum, Vol. 45— No. 1993. 



549 



