196 



GANNET. 



nature, which might otherwise be too quickly carried off, by the con- 

 stant circulation of fresh air that nearly surrounds them ; for this 

 integument is held only by ligaments to the back and front, leaving- all 

 other parts free for inspired air. The liver and intestines are firmly 

 attached to the surrounding- integument ; the heart is enveloped by a 

 similar covering, which is only partially connected to the common one. 



In the trachea nothing very remarkable occurs, except two small 

 glands about the size of a pea, at the lower extremity. The tongue is 

 so extremely diminutive, as scarcely to be entitled to that denomina- 

 tion. The clavicles, or what is commonly called the merry-thought, 

 which are usually affixed to the point of the keel of the breast-bone by 

 a ligament, is in the Gannet so firmly united as to appear a part of it. 



From what has been already observed, it will not be unreasonable to 

 conclude, that the Gannet is endowed with such singular properties, for 

 very different purposes than those of long and continual immersion, of 

 which we have before stated it appears to be incapable. But such a 

 power of inflation must contribute greatly to lessen the concussion in 

 its rapid descent upon water, in order to seize its prey. Besides, as the 

 enlargement of the surface, without materially adding to the specific 

 gravity, must greatly contribute to its buoyancy both in air and water, 

 it is well adapted for residing in the midst of the most tempestuous sea, 

 floating on its surface in perfect security, and following those shoals of 

 fishes on which depends its whole existence. Thus, when all other 

 birds are compelled to seek shelter in bays and creeks, the Gannet is 

 enabled to brave the severest weather in all seasons, without attempting 

 to near the shore. 



This contrivance may also be of the most important service to an 

 animal which is constantly exposed, even in the most inclement season, 

 and cannot quit its station without starving. Nothing could possibly 

 conduce more to its security against intense cold, or be better adapted to 

 preserve the necessary temperature of animal heat, than the intermedi- 

 ate air dispersed between the skin and the body, since that element is 

 found to be a non-conductor of caloric. Upon this principle, what 

 animal can be more securely protected against cold, or retain its vital 

 heat so effectually as the Gannet ; or such birds as are almost sur- 

 rounded with a body of confined air, divided by cells, and intersected by 

 membranes between the skin and the body, and that skin so amply 

 covered with a light porous substance, filled also with air, and imper- 

 vious to water. 



The Gannet is capable of containing about three full inspirations of 

 the human lungs, divided into nearly three equal portions, the cellular 



