Vol. 5, p. 333-339. pi. 17. January 9, 1931. 



Occasional Papers 



OF THE 



Boston Society of Natural History. 



LAND SHELLS FROM LUBANG ISLAND, 

 PHILIPPINES. 



BY WILLIAM J. CLENCH AND ALLAN F. ARCHER. 



The following list and new forms are based upon a collection 

 made by Sefior Pedro de Mesa, formerly of Lubang Island, now 

 a resident of Calapan, Mindoro, Philippine Islands. It is quite 

 probably complete in the larger forms of land mollusks to be 

 found on this small island. 



Lubang Island is situated some 17 miles off the northwestern 

 end of the Island of Mindoro and about 25 miles west of Luzon. 

 Its mollusk affinities are quite apparently with those of Luzon 

 and not Mindoro, although there are a few species common to 

 all three islands. Perhaps the most outstanding of the Lubang 

 element is that of Helicostyla cepoides Lea. The affinities of 

 this species are clearly with those of the Helicobulinus group of 

 Luzon and the Central Philippines. Likewise the presence of 

 H. pithogostra on Lubang is another connecting link with the 

 Luzon fauna. This species is widely distributed throughout 

 Luzon and the Central Philippines, but is not known to occur 

 in Mindoro. 



Helicostyla cincinniformis, another species peculiar to the 

 Island, belongs in the section Hypselostyla, a stock which is 

 found largely in Luzon and the central Philippines, and probably 

 had its start in Luzon. It has no known representatives in 

 Mindoro. 



The authors are indebted to Mr. E. G. Vanatta for the deter- 

 mination of Pseudhelicarion compactus Q. and M., and to Sefior 

 de Mesa for his kindness in supplying the material for study. 



333 



