AVES. 223 



it is developed by incubation, unless the heat of the climate 

 suffices for that purpose, as is the case with the egg of the 

 Ostrich. The young Bird has a little horny point at the 

 extremity of the beak, with which it splits open the shell, and 

 which falls oif a few days after it is hatched. 



The industry and skill exhibited by Birds in their variously 

 constructed nests, and their tenderness and care in protecting 

 their eggs and young, are known to every one ; it is the prin- 

 cipal part of their instinct. Their rapid transitions through 

 different regions of the air, and the vivid and continual action 

 of that element upon them, enable them to anticipate atmos- 

 pheric changes, to an extent of which we can form no idea, 

 and caused the ancients, in their superstition, to attribute to 

 them the power of prescience or divination. It is unques- 

 tionably on this faculty, that depends the instinct which acts 

 upon the Birds of passage, prompting them to seek the south 

 on the approach of winter, and the north on the return of 

 spring. They have memory, and even imagination for they 

 dream. They are easily tamed? may be taught to render 

 various services, and retain the air and words of songs. 



Division of the Class of Birds into Orders. 



Of all classes of animals, that of Birds is the most 

 strongly characterized, that in which the species have the 

 greatest mutual resemblance, and which is separated from all 

 others by the greatest interval ; circumstances which, at the 

 same time, render its subdivision the more difficult. * 



Their distribution is founded, like that of the Mammalia, on 

 the organs of manducation or the beak, and on those of pre- 

 hension, that is, on the beak, and particularly on the feet. 



The first that arrest our attention are the palmatedfeet, or 

 those in which the toes are connected by membranes, which 

 distinguish all Swimming Birds. The position of these feet 

 behind ; the length of the sternum ; the neck, often longer 

 than the legs to enable it to reach below ; the dense, polished 



