CHAP. XIX.] THE MADAGASCAR GROUP. 



407 



The smaller and more remote Eodriguez is also volcanic; but it 

 has, besides, a good deal of coralline rock, an indication of partial 

 submergence and helping to account for the poverty of its faunas 

 and flora. It stands on a 100-fathom bank of considerable extent, 

 but beyond this the sea ra,pidly deepens to more than 2,000 

 fathoms, so that it is truly oceanic like its larger sister isles. 



Birds. — The living birds of these islands are few in number 

 and consist mainly of peculiar species of Mascarene types, 

 together with two peculiar genera — Oxynotus belonging to the 

 CampephagidEe or caterpillar- catchers, a family abundant in the 

 old-world tropics ; and a dove, Trocazza, forming a peculiar sub- 

 genus. The origin of these birds offers no difficulty, looking at 

 the position of the islands and of the surrounding shoals and 

 islets. 



Extinct Birds. — These three islands are, however, pre-eminently 

 remarkable as being the home of a group of large ground -birds, 

 quite incapable of flight, and altogether unlike anything found 

 elsewhere on the globe ; and which, though once very abundant, 

 have become totally extinct within the last two hundred years. 

 The best known of these birds is the dodo, which inhabited 

 Mauritius ; while allied species certainly lived in Bourbon and 

 Eodriguez, abundant remains of the species of the latter island 

 — the "solitaire," having been discovered, corresponding with the 

 figure and description given of it by Legotiat, who resided in 

 Eodriguez in 1692. These birds constitute a distinct family, 

 Dididse, allied to the pigeons but very isolated. They were 

 quite helpless, and were rapidly exterminated when man intro- 

 duced dogs, pigs, and cats into the islands, and himself sought 

 them for food. The fact that such perfectly defenceless creatures 

 survived in great abtindance to a quite recent period in these 

 three islands only, while there is no evidence of their ever 

 having inhabited any other countries whatever, is itself almost 

 demonstrative that Mauritius, Bourbon, and Eodriguez are very 

 ancient but truly oceanic islands. From what we know of the 

 general similarity of Miocene birds to living genera and families, 

 it seems clear that the origin of so remarkable a type as the 

 dodos must date back to early Tertiary times. If we suppose 

 some ancestral ground-feeding pigeon of large size to have 



