1871.] MR. HARPER PEASE ON POLYNESIAN LAND-SHELLS. -4-19 



I have now little doubt that the figure of the skeleton by Cuvier 

 and the skull which my son-in-law brought from Para, on which I 

 founded A. problemuticiis, belong to A.flaccidus. We have also a 

 skeleton which appears to belong to the same species in the British 

 Museum. 



5. Catalogue of the Land-shells inhabiting Polynesia, with 

 Remarks on their Synonymy, Distribution, and Variation, 

 and Descriptions of New Genera and Species. By W. 

 Harper Pease, C.M.Z.S. 



[Eeceived April 4, 1871.] 



The geographical limits of Polynesia may be determined from the 

 distribution of its land-shells, as distinctly as by that of its marine 

 mollusca and zoophytes. They characterize it as being a distinct 

 zoological province, separate from the East-Indian. 



It is not only the largest in extent, but the most isolated in posi- 

 tion of any on the surface of the earth. Stretching over nearly one 

 fourth of the whole circumference of the globe, and from one extreme 

 of the tropics to the other, it is separated by a wide expanse of ocean 

 on three of its sides, north, east, and south, from the nearest pro- 

 vinces. On the extreme west, at the Pelew Islands, it comes into con- 

 tact with the Philippines, and a short distance south, at the Samoas, 

 with the Papuan Islands. 



I do not propose to enter into a critical examination of the distri- 

 bution and variation of the several genera and species, their relation 

 to those inhabiting the neighbouring provinces and their probable 

 origin, as it would involve the discussion of several collateral ques- 

 tions, such as the origin of the islands, their topography, formation 

 of valleys, &c, which I am not at present prepared to enter on. 



As to general distribution I note the following facts. In West 

 Polynesia, comprising the Pelews, Ladrones, Caroline, Ralick, and 

 Radack groups, a few East-Indian types have entered, but do not 

 prevail, the Polynesian predominating. Of Helices two species of 

 the large Philippine forms occur, viz. H. pelewana, Pfr., at the 

 Pelews, and H. sowerbyana, Pfr., at Hogoleu. All the others are of 

 Polynesian types. 



The genus Pitys, so prolific in species throughout all other parts 

 of Polynesia, is not represented by a single species. Partulce occur 

 on all the islands. 



Of operculated genera the East-Indian Diplommatinacea are re- 

 presented by the genus Palaina at the Pelews, and one species at 

 Ponape ; they extend no further. All the species of Omphalotropis 

 are of the East-Indian type, carinate at the umbilicus, and more or 

 less varied with colours. One species referred to Cyclophorus and 

 one to Cyclostomus, both of doubtful genera, have been found at 



Proc. Zool. Soc— 1871, No. XXIX. 



