THE ISLANDS OF THE BAY OF BENGAL. 139 



The questions then for solution are : How is it that these 

 islands exhibit broadly ' viewed an essentially Indian ornis, 

 when according 1 to all a priori reasoning it might have been 

 expected to be almost exclusively Indo-Bnrmese, Indo-Malayan 

 and Archipelagian ? And how being Indiau it wants so many 

 of those genera, that are especially characteristic of that region 

 as we now know it, and whose absence cannot be attributed 

 to any want of suitability in the physical conditions of 

 existence ? 



These questions cannot be satisfactorily answered without 

 opening up a vast and complicated subject, embracing enor- 

 mous areas and stretching over untold aeons, a subject which 

 I have long since reserved for a separate work. Hei*e it 

 must suffice to say that there appear to me valid reasons for 

 believing that the ornis of the Indian region proper, extended 

 at one time much further east and south than it now does, that 

 both the Indo-Burmese and Indo-Malayan Avifaunas, are 

 invaders of the regions they now occupy, driven northwards 

 and westwards by a continually widening ocean, and that the 

 disappearance of an enormous area of dry land, southwards 

 and eastwards of their new homes by its influence on the 

 monsoons, and modification of climatic conditions generally, 

 rendered vast tracts where the Indian ornis once reigned 

 supreme, as unsuited to this, as it was congenial to the fugitives. 

 Lastly, during the long ages that must have elapsed, while the 

 evolution of so many specialized forms occurred, I believe that 

 great changes were brought about in the parent fauna, and that 

 many of those genera and species which we now look upon as 

 characteristic of the Indian region, date their introduction 

 into it to a period posterior to the separation of these islands 

 from the mainland. 



IV. — Detailed list of Species, 



I have now to enumerate all the species admitted by myself 

 and others into the Ornis of these islands. 



' Names of species which I admit have been printed in antique 

 type, while those whose claims to admission appear to me inade- 

 quately established, are printed in ordinary lype. 



After the name of each species, certain figures are given 

 within brackets. These indicate the number of the specimens 

 that I have obtained. This is I consider of importance, firstly, 

 because it exhibits the breadth as it were, of the basis, on 



