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THE WORLD'S BIRDS. 



Ostriches {StruthionidcB). 



Diagnosis. — Two-toed birds of gigantic size and in- 

 capable of flight. 



Size. — The largest of living birds, standing seven or 

 more feet high. 



Form. — Bill short, straight, flat ; the corner of mouth 

 beneath centre of eye. Legs with the thigh (really 

 the tibial segment) prominent and very stout ; 

 shank long and stout ; two toes only present (the 

 third and fourth), the inner largest and alone pro- 



Foot of Ostrich. 



vided with a claw ; the toes are united at the base 

 by a web, and the basal joints are raised above the 

 ground when the bird walks, a unique peculiarity 

 in the class. Wings small, only bent at the 

 elbow, clawed on the first two fingers, and carried 

 loosely. Neck exceedingly long, body meagre. 

 Tail well feathered. 

 Plumage. — Loose and decomposed, even the quills of 

 the tail and wings ; there are no feathers under the 

 wings, or on the sides and thighs, and on the head 

 and neck only hair-Uke ones. Hair-like feathers 



