PARTS OF ANIMALS, IV. xii. 



upright ; and if it had an ischium which extended 

 only a short way from the fundament and was fol- 

 lowed immediately by the leg (as in man and the 

 quadrupeds), it would be unable to stand up at all. 

 Man can stand upright, and quadrupeds have fore- 

 legs to support their forward weight ; birds, how- 

 ever, neither stand upright (because they are dwarf- 

 like), nor have forelegs (because they have wings in- 

 stead). ** By way of compensation, Nature has made 

 the ischium long, reaching to the middle of the 

 body, and has fixed it fast, while beneath it she has 

 placed the legs, so that the weight may be equally 

 distributed on either side and the bird enabled to 

 walk and to stand still. This shows why birds are bi- 

 peds although they are unable to stand upright. The 

 reason why their legs are lacking in flesh is the same 

 as for all quadrupeds and has been stated already.^ 



All birds, web-footed or not, have four toes on each 

 foot. (The Libyan ostrich will be dealt with later, ^ 

 and its cloven hoof and other inconsistencies with the 

 tribe of birds will be discussed.) Of these four toes, 

 three are in front, and the fourth is at the back in- 

 stead of a heel, for stability. In the long-legged 

 birds this toe is deficient in length, as for instance in 

 the Crex. Still, the number of toes does not exceed 

 four. This arrangement of the toes holds good gener- 

 ally, but the A\Tyneck is an exception, for it has only 

 two toes in front and two at the back. This is because 



" See above, 693 b 3 ff . 



* See 689 b 10 ff. 

 <= At the end of the book. 



* ixevetv Y6 : fievrj vulg. 



' Sia TTjv orevoTT^ra rod (jkcXovs add. PY6. 



' efjLTTpoadev . . . oniadev Karsch : OTnadev . . . efXTrpoodev vulg. 



415 



