THE GANNET'S ANATOMY 



525 



perfectly the character of these singular and extensive 

 air-cells in the Gannet, but they are not easy of 

 delineation, except in small parts. 



V^»N.A-|/- 



gannet's subcutaneous air-cavities. 

 That the air-sacs which envelop the body are emptied 

 by muscular contraction, and filled again by inhaling air 



