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Show 1892.] THE LAND-MOLLUSCA OF THE PHILIPPINES. 461 Thus Basilan is, as might be expected, thoroughly Philippine, not possessing even one peculiar species. The Mollusca known from Malanipa are :- Xesta mindanaensis, Semp. Also occurs in Mindanao. Chloritis sanziana, H . & J. „ Mindanao. Obbina bigonia, Fer. „ Mindanao, Leyte, Samar. Leptopoma vitreum, Less. „ Philippines generally. The only Mollusca which appear to be known from Soo-loo are:- Trochomorpha metcalfei, Pfr. Cochlostyla lais, Pfr. Melania soolooensis, Brot. 1 Cyclotus suluanus, Mollf., M S . According to Hidalgo2, Cochl. lais occurs in N . Mindanao. The species is probably only a variety of puella, Brod. Pfeiffer originally described it from the Philippines generally ; in the ' Novitates,' iv. tab. 126. ff. 6, 7, p. 114, he figures a var. said to be from Tukan Bessi, a locality which I greatly doubt. In the absence of any information as to Tawi-tawi, it is impossible to say how far Philippine influence extends along this ridge. The Mollusca known3 from Bongao are :- Plectotropis squamulifera, Mollf. Peculiar. Macrochlamys angulata, Mollf. Peculiar. Trochonanina conicoides, Mete. Peculiar. Opeas, two species not identified. Opisthoporus, sp. (possibly a Cyclotus). Leptopoma, sp. Lagochilus quinqueliratus, Mollf. Peculiar. Alyceeus excisus, Mollf. Peculiar. Diplommatina roebelini, Mollf. Peculiar. Pupina ottonis, Dohrn. Also occurs in Philippines. Helicina martensi, Issel. „ Borneo. Thus six out of the eight known species are peculiar, while of the remaining two, one occurs in the Philippines and one in Borneo. As to genera, no exclusively Philippine genus occurs, while Plectotropis, Macrochlamys, Trochonanina, Opisthoporus, Lagochilus, and Alyceeus are Indo-Malay. In spite, then, of the deep intervening channel, Bongao is distinctly Bornean, and, in spite of the chain of islands with shallow water between them, distinctly non-Philippine. Coming to the western ridge, the Mollusca known from Balabac4 are as follows :- Amphidromus B 1 entobaptus, Dohrn. Also occurs in Palawan. 1 In the Brit. Mus., from the Hungerford collection. 2 Journ. de Conch. 3e ser. xxxv. p. 113. 3 Von Mollendorff, Jahrb. deutsch. malak. Gresell. xiv. p. 286. 4 From the island of Balambangan, on the Bornean side of Balabac Strait, are recorded Ariophanta regalis, Bens., and Cyclophorus tenebricosus, Ad. and Eve., and from an islet between Banguey and Balambangan, Amphidromus adamsii, Eeeve. 5 This is the species called by Hidalgo contrarius, Mull., which occurs in Timor. PROC. ZOOL. SOC-1892, No. XXXII. 32 |