BIRDS. 217 



class have naturalists arranged them into orders? 4. Describe the 

 first order of mammalia, — second, &c. 5. What are the orders of 

 mammalia according to Linnseus ? [Note. The distinctive charac- 

 ters of the Linnsean orders of mammalia, with the exception of the 

 last, depend on the kind, position, and number of the teeth, and thus 

 animals of very different habits were brought together, from a resem- 

 blance in one comparatively unimportant particular.] 



LESSON 97. 



Birds. 



Ornithology, that branch of natural history which describes the 



structure, economy, habits, &c. of birds. 

 Vis'cid, glutinous, tenacious. 



The immense catalogue of the species of birds, and the 

 variety and beauty of their external characters, have made 

 them favourite objects of investigation with the natural his- 

 torian. The extraordinary degree of instinct displayed in 

 all (heir habits and economy, more especially in the con- 

 struction of their nests, the care of their young, and the 

 conduct of their migrations, have called forth the admiration 

 of the philosopher and the lover of nature. The splendid 

 colouring of their plumage, the powers of melody, and the 

 liveliness and docility of many species, have given them 

 value as objects of beauty and entertainment. 



The class of birds is divided, according to their structure 

 and habits of life, into six orders. Birds of prey, or rapa- 

 cious birds [accip'itres) correspond, in many respects, with 

 the carnivorous animals among quadrupeds. They are dis- 

 tinguished by their strong, hooked beaks, and their crooked 

 and powerful talons. • They are particularly remarkable for 

 the very great distance at which they perceive their prey, 

 and the accuracy with which they direct their flight towards 

 it. Besides the upper and under eye-lids, all birds have a 

 third which is semi-transparent, and serves the purpose of 

 protecting the eye from the contact of external bodies, or 

 from too powerful light, whilst at the same time it does not 

 prevent them from distinguishing the objects around them. 

 This membrane is situated at the inner angle of the eye, 

 and is drawn over the globe of it, like a curtain, at will. It 

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