1892.] THE LAND-MOLLUSC A OF THE PHILIPPINES. 461 



Thus Basilan is, as might be expected, thoroughly Philippine, 

 not possessing even one peculiar species. 



The MoUusca known from Malanipa are : — 

 Xesta mindanaensis, Semp. Also occurs in Mindanao. 

 Ckloritis sansiatia, H. & J. „ Mindanao. 



Obbina hiffonia, Fer. „ Mindanao, Leyte, Samar. 



Leptopoma vitreum, Less. „ Philippines generally. 



The only MoUusca which appear to be known from Soo-loo are: — 

 Trochomorpha metcalfei, Pfr. 

 Cochlostyla lais, Pfr. 



Melania soolooensis, Brot. . . . /•- 



^ Cyclotus suluanus, Mollf., MS. fCy- (y^^^4^. 'r^^^**^' 



According to Hidalgo % 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 MoUusca known ' from Bongao are : — 



Plectotropis squamulifera, Mollf. Peculiar. 



Maerochlamys angnlata, Mollf. Peculiar. 



Trochonanina conicoides. Mete. PeettHaf. a^'-Vt? '!>VHL« • 



Opeas, two species not identified. 



Opisthoporus, sp. (possibly a Cyclotus). 



Leptopoma, sp. 



Laffochilus quinqueliratus, Mollf. Peculiar. 



Ahjcceus exeisus, Mollf. Peculiar. 



Diplommatina roehelini, MoUf. Peculiar. 



Pupina ottonis, Dohrn. Also occurs in Philippines. 



Helieina 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 Plecto- 

 tropis, Maerochlamys, Trochonanina, Opisthoporus, Layochilus, and 

 AlyccBus 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 MoUusca known from Balabac * 

 are as follows : — 



Amphidromus ' t entobaptus, Dohrn. Also occurs in Palawan. 



^ In tbe Brit. Mus., from the Hungerford collection. 



^ Journ. de Conch. 3^ ser. xxsv. p. 113. / 



' Von Mollendorff, Jahrb. deiitsch. malak. Gesell. xiv. p. 28(^. U~i 



* From the island of Balambangan, on the Bornean side of Balabac Strait, ' 



are recorded Ariophayita regalis, Bens., and Cyclophorus tmebricosus, Ad. and 



Rve., and from an islet between Banguey and Balambangan, Amphidromus 



ada?nsii, 'ReeYe. r^t^c ■ ,_• ^n- j - — 



» This is the species called by Hidalgo o*«67wW,-Mtttt., which occurs in 



Timor. 



Proc. Zool. Soc 1892, No. XXXII. 32 



