78 THE STORY OF THE BIRDS 



posterior margin ; the episternal process is per- 

 forated to receive the base of the coracoids, 

 except in the Hoatzin. The hind toe is always 

 present, but varying in size and position ; the 

 body feathers have a well-marked hyporhachis 

 or aftershaft. The bill is comparatively short 

 and stout, curved and wide at the base, the upper 

 mandible overhanging the lower one. The wings 

 are comparatively short and rounded ; the tail is 

 most variable, not only in shape but in number 

 of rectrices. The young are hatched covered 

 with down, and able to run as soon as hatched. 

 In no other order do we find greater diversity 

 of external characters. The great variety and 

 brilliancy of the wattles, combs, and excrescences 

 that decorate the head, the development of spur, 

 the magnificent colours and bewildering variety 

 in the plumage, and the wonderful modification 

 of the tail-feathers and coverts, would require 

 many pages of description to do them justice, 

 whilst a similar remark applies to the diversity 

 of habits. About 400 species and races are 

 known. 



Following the Galliformes we have here to 

 notice another small and yet very characteristic 

 order, namely the Pediophili or Sand-Grouse. 

 The position of these birds in the avine system 



