^46 FOOT OF THE EMU. 



is lifted clean and high above the ground. As the 

 ostrich is the swiftest of all running birds, we must 

 conclude that this is the best running foot upon dry 

 surfaces ,• but it cannot be considered as the normal 

 foot of the group, for the others have three toes, and 

 the cassowary has a long nail on the inner one, and 

 the tarsi feathered a great way down. 



The foot of the emu is intermediate between that 

 of the ostrich and common walkino; feet. 



The swift-footed birds which frequent the dry 

 shores and heaths, but which have occasionally to 

 pass over surfaces more or less humid or soft, have 

 three toes before, and none behind in some species, 

 a mere rudiment in others, but not a very large toe 

 in any. They have the middle and outer toes, more or 

 less united by membrane at the base, according as 

 the surface on which they generally run is more or 

 less soft. They are all birds of flight, not having the 

 muscles concentrated on the hind legs, like the 

 ostriches, and their legs are in genergJ slender ; and 

 though many of them run fast, they cannot take com- 



