LUNGS, BRONCHI, AND AIR-CELLS. 



17 



lunffs over the lobes of the liver. The two abdominal cells, 

 which are the largest in the body, commence at the lower 

 part of the lungs, above the hepatic cells, and extend to the 

 extremity of the abdomen ; they are generally separated by 

 a longitudinal mediastinum, and are frequently divided into 

 numerous cavities. The pelvic cells occupy the posterior part 

 of the pelvis, and with them and the abdominal communicate 

 the inguinal, whence there is a passage into the femoral bone, 

 and which are continuous with others extending along the leg. 

 Besides these there is a general envelope of cells interposed 

 between the skin and the muscles, which is especially apparent 

 in many aquatic birds, and which is capable of being inflated 

 from the lungs. Such is the ordinary distribution of the cells ; 

 but it must not be expected to find them always disposed in 

 the regular order in which they have been represented. The 

 accompanying diagram indicates their form and position in the 

 Rook, viewed from beneath. The interclavicular cell is marked 

 a ; the cellules of the neck, b b. The 

 lateral thoracic cells, c c, form a series of 

 various sizes ; the inferior thoracic, d, may 

 be described as a single large cell inter- 

 sected by filaments extending from the 

 pericardium to the sternum. The two 

 hepatic cells, e e, cover the two lobes of 

 the liver, and are undivided. The lateral 

 abdominal cells, which are the largest in 

 the body, are each divided into two great 

 cavities. On the left side, a great cell, /, 

 covers the lower part of the lung and a 

 portion of the left side of the stomach, 

 wdiile another, cf, extends from it and the 

 left hepatic cell, e, to near the anus. On 

 the right side the cell h is contiguous 

 with the right hepatic cell, and covers a large portion of the 

 intestine, while that marked i includes part of the duodenum. 

 The pelvic cells, j j, are small, and very numerous. 



It is not necessary that we should enter into a more mi- 

 nute examination of this peculiar disposition of the cellular 



VOL. II. c 



Fig. 107. 



