8 4 



THE WORLD'S BIRDS. 



OSTRICHES (Struthionidce}. 



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-like ones. Hair-like feathers 



