424 CLASS AVES. 



pivot on which the movement is executed. The two extre- 

 mities of the pulley are the two planes in a right line ; and 

 the elasticity of the ligament produces the same ejffect as the 

 spring applied against them. 



In the first family of the Grallae, in the " Regne Animal," 

 (the Brevipennes,) the genus of the Ostkich stands fore- 

 most. Linnaeus, under the denomination of Struthio, has 

 united the four terrestrial birds hitherto known, whose wings 

 are unfitted for the purposes of flight, namely, the ostrich, 

 the emu, the cassowary, and the dodo. He has placed them 

 in the order gallinae, to which, in truth, the form of their bill, 

 the weight of their body, and the nature of their terrestrial 

 habits, give them, by no means, an imfounded claim. It is 

 in the elevation of their limbs alone that the first three ap- 

 proach the grallae. But there are very essential diff'erences 

 between these birds, which sufficiently justified Brisson in 

 separating them into distinct genera, under the names of 

 struthio, rhea, casuarius, and rajihus. The first has but two 

 toes in front, and none behind. The second has three toes in 

 front, and a simple callosity instead of thumb. The third 

 has also three toes before, bvit no callosity behind, and is fur- 

 ther distinguished by the corneous casque which it bears 

 upon its head. As to the fourth, which in all probability is 

 not entitled to any rank among existing beings, the toes are 

 said to have been four in number, and the legs consider- 

 ably shorter than those of the others. We shall speak a little 

 more concerning this supposed bird, hereafter ; which, if it 

 ever existed, appears now to be extinct : while the ostrich, of 

 which mention is made in the Old Testament, has subsisted 

 from the earliest times, and always in the same regions, 

 namely, throughout all Africa, from Barbary to the Cape of 

 Good Hope. 



The ostrich is the most gigantic of all the feathered-race. 

 It attains to seven and eight feet in height, and weighs as 



