REPORT ON THE SPHENISCID.E. 



•213 



The Lungs. 



The lung oi Eudyptes chrysocome from Tristan (PL XII. fig. 6) is triangular in form. 

 Its external surface is uniformly convex and smooth, with the exception of six 

 fissures, which extend from the upper border of the organ obliquely backwards and 

 downwards towards the inferior margin. These fissures correspond in position to the 

 seven anterior vertebral ribs, which in the Penguins, as in other birds, indent the lung 

 substance. The inner surface of the lung is slightly concave, and receives the vessels 

 and nerves which constitute its root. These enter the lung midway between its apex and 

 base, and occupy a similar position with reference to the superior and inferior borders of the 

 organ. On this surface of the lung there are four separate apertures, by means of which 

 certain of the air-cells, to be presently described, are supplied with air during the process of 



