LECTURE V. 15& 



tendinous coat, and furrowed on the inside*. lit 

 this receptacle the food is completely ground and 

 reduced to a pulp. The lungs of Birds differ 

 from those of quadrupeds in not being loose or 

 free in the breast, but fixed to the bones all 

 the way down : they consist of a pair of large 

 spongy bodies, covered with a membrane which 

 is pierced in several places, and communicates 

 with several large vesicles or air-bags dispersed 

 about the cavities of the body. 



The eyes pf birds are more or less convex 

 in the different tribes ; and in general, it may be 

 observed that the sense of sight is more acute in 

 birds than in most other animals ; and they seem 

 to possess a greater degree of power in accom- 

 modating the convexity of the eye to any par- 

 ticular distance than other animals, for which 

 purpose they are provided with a curious ap-^ 

 paratus of scales round the iris or coloured part 

 of the eye not be observed in quadrupeds. Birds 

 have no outv\ard Ear, but the internal is formed 

 on the same general plan as in quadrupeds. 



Birds as every one knows are oviparous ani- 

 mals, always producing Eggs, from which the 



* In the predaceous birds or Accipitres this is wanting, the sto- 

 mach being alhed to that of quadrupeds, 



