66 



THE COMMON AMERICAN PARTRIDGE. 



voluted. They are marked with oblique-branched ridges on the inner sur- 

 face. The intestine at this part is 2 twelfths in width; the rectum, a b, 2\ 

 twelfths, without cloacal enlargement. j 



The trachea is 3 inches 2 twelfths long, flattened; its breadth at the top 2 

 twelfths, at the lower part 1 twelfth; its rings cartilaginous, about 85; the 

 lower very large, with a membrane intervening between its two portions. 

 The lateral muscles are strong, but there are no inferior laryngeal muscles. 

 The rings of the bronchi are only 10. 



Fig. 1. 



Fig. 2. 



a 



