621 



EXPLANATION OF THE PLATES ILLUSTRATTVE 

 OF THE ORDERS, FAMILIES, AND GENERA. 



The objects are represented half the natural size • 



Plate VI. Digestive Organs of the Brown Ptarmigan, Lagopus 



scoticus. 



Fig. 1. Alimentary Canal, Trachea, 

 Heart and Liver. 



a, the tongue. 



h, b, hyoid bones. 



b, e, oesophagus. 



c, d, crop. 

 /, gizzard. 



g, h, i, duodenum. 

 ff, h, i, j, k, intestine. 

 a, m, trachea. 



Fig. 2. Coeca and part of Intestine. 



a, b, part of the intestine, including its 

 extremity, b, near which the ureters 

 are seen to enter. 



c, the point at which the coeca come 

 off. 



c» d, e,f, g, h, the two coeca, narrower 

 at their commencement, then cylin- 

 drical, marked with about seven 

 longitudinal white bands, and ter- 

 minating in mammillar points, g, h. 



Fig. 3. Lower part of (Esophagus, and 

 Gizzard. 



a, oesophagus. 



b, proventriculus. 



c, d, e,f, g, gizzard. 



c, upper or anterior muscle. 



d, e, lateral muscles. 

 /, tendinous space. 

 g, lower muscle. 



h, intestine. 



Fig. 4. Gizza^'d and Proventriculus laid 

 open. 



a, part of oesophagus laid open. 



b, proventriculus laid open. The glan- 



dules are seen in the section, and 

 their orifices on the inner surface. 



c, gizzard laid open. 



d, e, lateral muscles. 



f, outer or muscular coat. 



g, middle coat. 

 h, inner coat. 



i, cylindrical mass of food. 



Plate VII. Digestive Organs of the Rock Dove, Columba Livia. 



Fig. 1. Alimentary Canal of a Wild Rock 



Dove, 

 a, the bill. 



^) C'tf ffi oesophagus, extremely dilated 

 at its upper part. 



d, e, crop, transverse, and somewhat 

 contracted in the middle. 



/, continuation of oesophagus, very nar- 

 row. 



g, proventriculus. 



