VERTEBRATA: AVES. 6l/ 



which fact, and of their being readily susceptible of domesti- 

 cation, they present an enormous number of varieties, often so 

 different from one another that they would certainly be de- 

 scribed as distinct species if found in a wild state. It seems 

 certain, however, that all the common domestic breeds of 

 Pigeons, however unlike one another, are really descended 

 from the Rock-pigeon (Columba lima\ which occurs wild in 

 many parts of Europe, and 'has retained its distinguishing 

 peculiarities unaltered for many centuries up to the present 

 day. Finally, the young of the Columbacei are born in a naked 

 and helpless state, whilst those of the Gallinacei are "preco- 

 cious," and can take care of themselves from the moment of 

 their liberation from the egg. 



Of the various living birds included in this section, the true 

 Pigeons (Columbida) are too well known to require any de- 

 scription ; but the Ground-pigeons (Gourida) depart to some 

 extent from this type, being ground-loving birds, more closely 

 allied to the ordinary Gallinacei. The Treronida, or Tree- 

 pigeons, are exclusively found in the Old World, in its warmer 

 parts, and are arboreal in their habits, living principally upon 

 fruits. The Didunculidcz are a small group, comprising only 

 the little Didunculus strigirostris of the Navigator Islands. In 

 this curious bird the wings are well developed, enabling it to 

 lead an arboreal life, and the upper mandible of the beak is 

 strongly arched and hooked towards its tip. The Didunculus 

 is of special interest as having certain relationships to the now 

 extinct Dodo, the representative of the family Didida. The 

 Dodo (Didus ineptus, fig. 341) formerly inhabited the island 

 of Mauritius, in great numbers, but the last record of its occur- 

 rence dates from the year 1681. It was a large and heavy bird, 

 bigger than a swan, and entirely unlike the Pigeons in general 

 appearance. The wings were rudimentary and completely 

 useless as organs of flight. The legs were short and stout, 

 the feet had four toes each, and the tail was extremely short, 

 carrying, as well as the wings, a tuft of soft plumes. The 

 beak (unlike that of any of the Columbacei except the little 

 Didunculus strigirostris] was strongly arched towards the end, 

 and the upper mandible had a strongly-hooked apex, not at 

 all unlike that of a bird of prey. The Dodo owed its exter- 

 mination to the fact that it was good to eat, and that it was 

 unable to fly. At present all the known remains of this 

 singular bird that exist are some old, but apparently faithful, 

 oil-paintings, and a few fragmentary remains, to which explor- 

 ations in the Recent deposits of the island have added a large 

 number of bones. Allied to the Dodo, and, like it, incap- 



