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PIGEONS AND SAND-GROUSE. 



the first being the Columbince, in which the tail is never longer than the wings ; 

 this group containing the wood-pigeon, stock-dove, and rock-dove, from the last- 

 named of which the domestic breeds of pigeon are derived. Of the first genus, 

 Gymnophaps, only one species (G. albertisi) peculiar to New Guinea is known, 

 which is distinguished from the allied genera by having the legs feathered for two- 

 thirds of their length, and a naked carmine space in front of and round the eyes. 

 Rock-Dove and We next come to the large and universally distributed genus, 



^^^^- Columha, containing about sixty species. All these birds resemble 

 the two following genera in never having the legs feathered for more than half 



ROCK-DOVE (i nat. size). 



their length, while they differ in having the first flight-feather of the wing longer 

 than the sixtL Space only permits of mentioning a few more important members, 

 among which must be included the rock-dove or blue rock (C. livia), widely spread 

 over Europe, and extending as far as India in the east, where it meets the nearly 

 allied but grey-rumped species (G. intermedia) ; southwards it ranges to the north 

 and west coasts of Africa, where another closely related form (C. gymnocyclus) is 

 found, differing only in having the plumage dark bluish or blackish slate-colour, 

 and perhaps descended from domestic pigeons. In the original wild stock of the 

 blue rock, the plumage is grey, the rump white, and the neck and upper breast 

 metallic green and purple, while there are two narrower black bars across the 

 wing and a broader one across the end of the tail. It is found in a wild state 

 where caves and deep fissures exist, and is common along the northern coasts of- 



