52 INTRODUCTION. 



taste in any considerable degree. The bill, Fig. 12, a, ^, and 

 the tongue. Fig. 12, r, are in fact more properly organs of 

 prehension than of gustation. 



The skin, being covered with feathers or hard ^ales, is sup- 

 J30sed to be very imperfectly adapted for communicating a 

 knowledge of the presence and nature of external objects ; and 

 it is very doubtful if those soft parts about the head, which are 

 destitute of feathers, such as combs, wattles, and ceres, are ever 

 employed for such a purpose. The bill however in many spe- 

 cies, especially Ducks and some of the Grallatores, being abun- 

 dantly supplied with nerves, and covered by a comparatively 

 soft membrane, is undoubtedly an efficient organ of touch. 



We come now to the consideration of the digestive organs, 

 which merit especial attention, on account, not so much of 

 their great importance in the economy of birds, as the nervous, 

 vascular, and other systems are not behind them in this re^ 

 spect ; but because, exhibiting great diversity of form and 

 structure, in accordance with the nature of the food^ they are 

 more obviously qualified to afford a basis for the classification of 

 the numerous species of birds. The parts of which the intestinal 

 canal are composed are the bill, the tongue, the cavity of the 

 mouth, the pharynx, the oesophagus, the crop, the proventri- 

 culus, the stomach, the small intestine, the coeca, the large in- 

 testine, and the cloaca ; to which may be added as accessory 

 organs, the salivary glands, the liver and the pancreas. Now, 

 as the object of these introductory observations is, not to give 

 a comparative view of the organization of birds, either with 

 reference to other animals, or as modified in the different orders 

 or families, but to disclose so much of it as may suffice to en- 

 able the reader to follow me in the generic and specific de- 

 scriptions, I shall take a bird of the Falconine family, as 

 presenting a form and structure of the digestive organs well 

 adapted for exhibiting all their parts, and for affording an ob- 

 ject of comparison with other tribes. 



In Plate IV. are represented the digestive organs of the 

 Peregrine Falcon, Falco ijeregrinus. Fig. 1, the bill ; 2, the 

 roof of the mouth ; 3, the tongue ; 4, the intestinal canal, con- 

 cealed in part by the trachea, the heart, and the liver ; 5, the 



