chap, xii.] THE ORIENTAL REGION. 361 



of specific and generic forms which have coincided with, and been 

 to a large extent dependent on them. We have, therefore, true 

 causes at work, and our only suppositions have been as to how 

 those causes could have brought about the results which we 

 see ; and however complex and unlikely some of the supposed 

 changes may seem to the reader, the geologist who has made a 

 study of such changes, as recorded in the crust of the earth, 

 will not only admit them to be probable, but will be inclined 

 to believe that they have really been far more complex and 

 more unexpected than any supposition we can make about 

 them. 



There is one other external relation of the Malayan fauna 

 about which it may be necessary to say a few words. I have 

 supposed the greatest westward extension of the Malayan area 

 to be indicated by the Maldive islands, but some naturalists 

 would extend it to include Madagascar in order to account for 

 the range of the Lemuridse. Such an extension would, however, 

 render it difficult to explain the very small amount of corre- 

 spondence with a pervading diversity, between the Malayan and 

 Malagasy faunas. It seems more reasonable to suppose an 

 approximation of the two areas, without actual union having 

 ever occurred. This approximation would have allowed the 

 interchange of certain genera of birds, which are common to 

 the Oriental Eegion and the Mascarene islands, but it would 

 have been too recent to account for the diffusion of the lemurs 

 which belong to distinct genera and even distinct families. This 

 probably dates back to a much earlier period, when the lemurine 

 type had a wide range over the northern hemisphere. Sub- 

 jected to the competition of higher forms, these imperfectly 

 developed groups have mostly died out, except a few isolated 

 examples, chiefly found in islands, and a few groups in Africa. 



In our discussion of the origin of the Ethiopian fauna, we 

 have supposed that a close connection once existed between 

 Madagascar and Ceylon. This was during a very early tertiary 

 epoch ; and if, long after it had ceased and the fauna of Ceylon 

 and South India had assumed somewhat more of their present 

 character, we suppose the approximation or union of Ceylon 



Yol. I.— 25 



