314 



THE PHILIPPINES 



CHAP. 



Fig. 212. — H'^Iix (Obhina) rota Brod., 

 Philippines. 



Other forms peculiar to the Philippines ai^ Diaphora, a 



section of Ennea with a curi- 

 ously produced mouth, and 

 several sub-genera of the 

 Naninidae ( Vitriniconus, Vit- 

 rinoidea, Hemitrlchia). The 

 great Rhysota here find their 

 metropolis. Another very 

 marked group of Helix is 

 Ohhina^ 19 of the 25 known 

 species being peculiar. 

 The Helicidae proper of the Philippines are still held in 

 check, as in the greater part of the Indian region, by the 

 Naninidae. The single Trachia and Plectotropis^ and the 2 

 species each of Plectopylis and Satsuuia^ indicate affinities with 

 Indo-China. Further important Indian relationships are seen 

 in the great Nanina and Cydophorus^ which here attain almost 

 Indian dimensions; in Kaliella (8 sp.), Sitala (2), ClausiUa 

 (1). Among the operculates we still have 1 Alycaeus and 1 

 Coptochilus. Singularly enough, several Indian genera which 

 occur here are not found in the intervening islands of Bor- 

 neo, Sumatra, or Java, e.g. Streptaxis, Hypselostojna^ Ditropis., 

 Acmella^ and Cyatliopoma. The curiously tubed Malay opercu- 

 lates, Opisthoporus^ etc., fail to reach the Philippines proper, 

 although occurring in Borneo and N. Celebes; one of them, 

 reaches Palawan. The strikingly Malay genus Amphidromus 

 reaches Palawan, but no farther (1 sp.), while 2 species reach 

 Mindanao, and one of these penetrates as far as Bohol and S. 

 Leyte. Amongst the slugs, 3IariaeUa occurs again only in the 

 Seychelles, and Tennentia only in Ceylon. 



Land and Fresh-water Mollusca of the Philippines 



