BIRDS. 303 



into the quills of the feathers. In the case of a wounded 

 Heron, respiration was carried on for an entire day through 

 a broken portion of the wing-bone.* 



Covering. Feathers, the peculiar and appropriate vesture 

 of birds, present every variety of texture and of tint that the 

 eye could desire, and far more than the imagination could 



. Lingual artery. 



Trachea. 



External carotid artery. 



Aorta. 



Renal 

 artery. 



Tschiatic 

 artery. 



Femoral 

 artery. 



Sacral artery. 



Fig. 241. ARTERIAL SYSTEM OP A BIRD. 



conceive. We see them in the Eagle compact and firm, in 

 the Ostrich loose and curling, in the Penguin reduced to rudi- 

 ments, resembling the scale-like covering of a fish, rather than 

 * Linnaean Transactions, vol. xi. p. 11. 



