PIGEON. 125 



difference is carried to the greatest excess, become 

 the types of other genera or groups. 



The Pigeons are characterized by a bill of mean 

 strength, the tip hard, bulging, and moderately arch- 

 ed, the nostrils partly covered and defended by a 

 large soft projecting membrane, the orbits more or 

 less naked. The feet formed for walking as well 

 as perching, the hind toe being of moderate length, 

 and the claws so shaped and disposed, as not to in- 

 terfere with their progress upon the ground ; the 

 outer and inner toes in the typical species are of the 

 same length. Their wings are fully developed and 

 rather acute, the second and third feathers being the 

 longest. The tail is generally square and of mean 

 length. 



In those species which are the media of connexion 

 with other groups, the above characters become 

 partially modified, as we see exemplified in the 

 species nearest allied to the Ptilinopinae or arboreal 

 pigeons, their feet losing the true character of that 

 of the Common Pigeon, and assuming more of the 

 grasping form than that fitted for progress upon the 

 ground. 



The prevailing colour of the Pigeons is bluish- 

 grey, of various intensities and shades, frequently em- 

 bellished upon the neck with feathers having a metal- 

 lic lustre and peculiar form, and which exhibit various 

 tints of colour, according to the light in which they 

 are viewed. They are naturally birds of a wild and 

 timid disposition (though one species has been partly 



