The geographical distribution of animals, with a study of the relations ...

chap, xii.] THE ORIENTAL REGION. 361of specific and generic forms which have coincided with, and beento a large extent dependent on them. We have, therefore, truecauses at work, and our only suppositions have been as to howthose causes could have brought about the results which wesee ; and however complex and unlikely some of the supposedchanges may seem to the reader, the geologist who has made astudy of such changes, as recorded in the crust of the earth,will not only admit them to be probable, but will be inclinedto believe that they have really been far more complex andmore unexpected than any supposition we can make aboutthem.There is one other external relation of the Malayan faunaabout which it may be necessary to say a few words. I havesupposed the greatestwestward extension of the Malayan areato be indicated by the Maldive islands, but some naturalistswould extend it to include Madagascar in order to account forthe range of the Lemuridse.Such an extension would, however,render it difficult to explain the very small amount of correspondencewith a pervading diversity, between the Malayan andMalagasy faunas. It seems more reasonable to suppose anapproximation of the two areas, without actual union havingever occurred. This approximation would have allowed theinterchange of certain genera of birds, which are common tothe Oriental Eegion and the Mascarene islands, but it wouldhave been too recent to account for the diffusionof the lemurswhich belong to distinct genera and even distinct families.Thisprobably dates back to a much earlier period, when the lemurinetype had a wide range over the northern hemisphere. Subjectedto the competition of higher forms, these imperfectlydeveloped groups have mostly died out, except a few isolatedexamples, chiefly found in islands, and a few groups in Africa.In our discussion of the origin of the Ethiopian fauna, wehave supposed that a close connection once existed betweenMadagascar and Ceylon.This was during a very early tertiaryepoch ; and if, long after it had ceased and the fauna of Ceylonand South India had assumed somewhat more of their presentcharacter, we suppose the approximation or union of CeylonYol. I.—25