190 SCANSORES. PSITTACID^E. 



feet are short and broad, and covered with nume- 

 rous small rounded scales. 



The power of moving the upper mandible, 

 which is wanting to the Mammalia, is common, 

 and almost universal, among Birds. In the present 

 Family, however, it is much more highly deve- 

 loped than in other birds ; the mandible not being 



SKULL OF MACAW. 



connected into one piece with the skull, by elastic 

 and yielding bony plates, as is the case with birds 

 in general, but constituting a particular bone, dis- 

 tinct from the rest of the skull, and jointed to it. 

 This mobility is rendered more conspicuous by the 

 circumstance of their vigorous jaws being set in 

 motion by a greater number of muscles than are 

 found in other birds. The advantages of this 

 peculiarity of structure are obvious, when we re- 

 member the use which a Parrot makes of this 

 organ, as a third hand, to assist it in climbing 

 from bough to bough, or about the bars of its 

 cage when in confinement. 



