GANNET. 1 5 



air-cells in the parts already mentioned, have a free com- 

 munication with the lungs, by means of openings on their 

 surface, through which the air passes readily into them. 



Thus far have the scientific researches of that anatomist 

 contributed to our knowledge on this subject. No one 

 appears to have noticed the phenomena attendant on the 

 construction of the Gannet, or to what further extent this 

 circulation of aerial fluid is carried in some particular species 

 of birds, a circumstance which demands our highest admi- 

 ration, when we contemplate the advantages of such a 

 structure in conducing to the comforts, and perhaps to the 

 very existence of such animals. On each side nearly 

 equidistant between this pectoral membrane and the back, 

 is situated another longitudinal one, very similar to the 

 last, but perforated; between this and the pectoral are about 

 nine irregular transverse membranous septa that hold the 

 skin firmly to the body, having a free communication with 

 each other. ' The skin is also furnished with a transparent 

 cellular membrane, the cells being regularly perforated close 

 to the base of each feather; at the upper part of the breast 

 is a large bag, which extends some way up the neck; this 

 is attached to the skin by the septa of innumerable small cells, 

 but no opening into this cellular bag could be discovered; 

 the introduction, however, of a small pipe through an 

 artificial aperture clearly demonstrated a passage to the 

 lungs, as the whole internal cavity of the body was inflated, 

 and the air issued from the trachea. Upon opening this 

 bag, the passage of communication with the internal parts 

 appeared to be under the shoulder blades, (clavicles,) as a 

 thin perforated membrane was perceived at the bottom, 

 leading to the thorax, not directly into the lungs, but near 

 the part where the trachea divaricates, and afterwards com- 

 municating with the lungs. It could not, however, be 

 discovered where the air could find a passage from the great 

 magazine into the cellular bag, and yet there is every reason 

 to conclude that at this part some valvular passage exists. 

 Pursuing our researches we observed at the bottom of each 

 lobe of the lungs a considerable opening for the passage of 

 air into the cavity of the body. 



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 



