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THE GEOGRAPHICAL RELATIONS OF 

 THE FLORA AND FAUNA OF CHRISTMAS ISLAND. 



By C. W. Andeews, B.Sc, F.G.S. 



Among the most interesting subjects of inquiry in connection with, 

 an oceanic island are the relations of its flora and fauna to those of 

 the neighbouring lands, the means by which it has been colonized, 

 and the degree to which the changed conditions under which the 

 colonists are placed have led to modifications and have given rise 

 to new species. In the present section these points are briefly 

 discussed, and a list of all the recorded species is appended, 

 together with their approximate distribution or that of their allies. 



The fauna and flora of Christmas Island are on the whole, as 

 might be expected, most nearly related to those of the Indo- 

 Malayan islands, but to this there are some exceptions in the 

 case of certain groups. Of the 319 species of animals recorded, 

 145 or about 45 per cent, are described as endemic : this 

 remarkably high percentage of peculiar forms is, however, no 

 doubt largely due to the fact that in some groups, particularly 

 the insects, the species inhabiting Java and the neighbouring, 

 islands are still imperfectly known, and many now described for 

 the first time from Christmas Island will no doubt probably be 

 found to exist also in other localities. 



Of the mammals all are peculiar species except one, and that is 

 a well-marked variety of a species inhabiting Further India. The 

 nearest allies of the Rats and Fruit-bat are found in the Austro- 

 Malayan islands, a circumstance for which an explanation is 

 offered below. 



The birds may be divided into four groups, (1) The resident 

 land birds, which are all peculiar species, more nearly allied to 

 Austro-ilalayan than to Indo-Malayan forms (Lister, Proc. Zool. 

 Soc, 1888, p. 530). (2) The sea birds, mostly widely spread forms, 

 but in one case, Sula ahbotti, previously recorded from Assumption 

 Island only, and in another, Phaetho)i fulvus, described from 

 specimens of which the locality is not known. (3) The migrants, 

 which reach the island during the rainy season, corresponding to 

 the northern winter. (4) Accidental visitors, to which division 

 Chalcococojx basalis and ITyyisticivonis bicolor may probably be 

 referred. 



Of the six reptiles four are peculiar, but belong to widely 

 distributed genera, and the other two occur in Java. 



