136 



STJBKINGDOM VERTEBEATA. 



Fig. 22,9. 



cycloid, which is a line of swifter descent than a perpendic- 

 ular, and also easier for alighting. 

 To give a more powerful hold on the 

 air when caiTying its prey to its 

 eyrie, its wings are hollow on the 

 under side. 



Cathartidse.* — The American 

 Vultures being designed in the econ- 

 omy of nature to dispose of carrion, 

 lack the powerful talons of the 

 Pal cons, but possess a strong beak 

 for dismembering the dead bodies on 

 which they feed. If one soaring aloft 

 detects with its telescopic eye a car- 

 cass, the change of its flight from a 

 circular sweep to a right line of 

 descent is probably noticed by many 

 others too distant to be seen by the human eye, and thus a 

 large flock quickly gathers from all quarters of the heavens.f 

 The head and neck are bare of feathers, to enable them to be 

 plunged deeply into a carcass. As the naked skin, however, 

 would suSer in the cold upper 

 air, the base of the neck is 

 encircled with a rnfl: of soft 

 down, arising from a loose 

 fold, into which the neck and 

 most of the head can be with- 

 drawn, while the bird remains 



Haliaetus leucocephdlus. 

 White-headed Eagle, j'j. 



Mg. 2S0. 



* Recent researches prove the Vultures 

 of the Old aud New World so osteologi- 

 callydilTerent as to require the latter to be 

 placed in a separate family, and the for- 

 mer to be degraded to the rank of a sub- 

 family of the Falcouidai, the Vulturinie. 



+ Both sight and smell seem to aid 

 them in the pursuit of their food. The 

 latter sense is remarkably keen, and they 

 have been seen to descend directly from 

 a great height in the air to putrefying food 

 that was concealed from their vision. 



Rhynogryphus aura^ 

 Turkey Buzzard. ,'3. 



