208 VERTEBRATE ANIMALS. 
The Columbacezt comprise the Pigeons and Doves, and they 
are separated from the typical Rasores by being much more 
fully adapted for flight. They are furnished with strong wings 
and are good fliers ; and in place of being ground-birds, their 
habits are to a great extent arboreal, in accordance with which 
the feet are slender and are adapted for perching. They are 
also not polygamous, and their voice is of a much more gentle 
Fig. 161.—Rasores. Rock-pigeon (Columdba livia). 
soft, and melancholy character. (Hence the name of Gemztores 
applied to this section, whilst the Gad/inacet are called the 
Clamatores.) Besides the true Pigeons and Doves, this sub- 
order includes also the remarkable extinct bird, the Dodo, 
which was of gigantic size, comparatively speaking, and in- 
habited the island of Mauritius up to the commencement of the 
seventeenth century. 
ORDER V, SCANSORES.—The order of Scansores or Climbing 
Birds is very shortly and easily defined, having no other dis- 
