436 ISLAND LIFE 



sea rapidly 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 j^eculiar species of Mascarene 

 types, together with two peculiar genera — Oxynotus 

 belonging to the Campephagida3 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 diTiculty, 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 having been 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 Rodriguez, abundant remains of the species of the 

 latter island — the "solitaire," having been discovered, 

 corresponding with the figure and description given 

 of it by Legouat, who resided in Rodriguez in 1692. 

 These birds constitute a distinct family, Didida?, allied to 

 the pigeons but very isolated. They were quite defenceless, 

 and were rapid-ly exterminated when man introduced dogs, 

 pigs, and cats into the island, and himself sought them for 

 food. The fact that such perfectly unprotected creatures 

 survived in great abundance 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 

 Rodriguez 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 ances- 

 tral ground-feeding pigeon of large size to have reached 

 the group by means of intervening islands afterwards 

 submerged, and to have thenceforth remained to increase 

 and multiply unchecked by the attacks of any more power- 



