EXPLANATION OF PLATE 2. 



Fig. 1. The thorax and abdomen of an Ostrich, opened to show the great 

 air cells which communicate directly with the lungs, and transmit the air 

 to different parts of the body, t, the trachea or wind-pipe — 6, the bronchiss 

 — pp, the lungs, the greater part of which are concealed by the great air 

 cells — c, c, c, c, air cells at the bottom of which may be perceived the open- 

 ings of the bronchiae — e, other cells, wliich communicate with the preceding 

 CO, the heart — g, the gizzard — i, the intestines. 



Fig, 2. The inferior larynx of a singing bird — t, the trachea — br, the 

 bronchiae — I, the inferior larynx — m, muscles of the vocal apparatus. 



Fig. 3. The tongue and trachea of a bird — I, the tongue — i, the cornu 

 of the OS hyoides — la, the superior larynx — tr, the trachea — g, the glottis. 



Fig. 4. The digestive apparatus of a pigeon — a, the oesophagus— _;, the 

 ingluvies or crop, — v, the proventriculus or bulbus glandulosus {See page 21.) 

 — g, the gizzard — i, the small intestine — ig, the large intestine—/, the liver — 

 pa, the pancreas — o, the ovary — ov, the oviduct — r, the kidneys — cu, canal 

 of the ureter — cl, the cloaca. 



