XIV IN TROD UC TION. 



lengthened enormously, and occasionally the feathers are 

 highly decorated by various markings or brilliant color- 

 ation. The flight is labored but rapid, and occasionally 

 protracted. 



In their anatomy these birds have various pecuHarities. 

 The esophagus is dilated, forming the crop which re- 

 ceives and moistens the food; while the gizzard, which 

 is present in all save the Sage Cock, is very strong, with 

 a thick, hard, interior wall. To assist this organ in grind- 

 ing the food the birds are in the habit of swallowing 

 small stones and other hard objects. The coeca are 

 highly developed. 



The species of this order are accustomed to lay numer- 

 ous eggs, to go in coveys of considerable numbers, com- 

 posed at times of one or more families, and the young, 

 which are at first covered with down, are able to run and 

 feed as soon as hatched. The family TETRAONiDyE, which 

 comprises the great majority of gallinaceous birds inhab- 

 iting North America, contains those known as Quails, 

 Partridges, and Grouse, and is represented in every por- 

 tion of the world. The members differ greatly from 

 each other in many particulars, and form three rather 

 natural groups or subfamilies, one of which, the Per- 

 dicinae, or Old World Quails and Partridges, are not 

 found upon the Western Hemisphere. American Par- 

 tridges have certain peculiarities, more particularly 

 described in the Appendix, which place them apart and 

 distinguish them from their relatives across the sea, 

 while certain species of Grouse have so wide a dis- 

 tribution, retaining at the same time their specific 

 characters, that they are found in high latitudes through- 

 out the world. This can be said of but very few 

 species of birds known to ornithologists at the present 

 day. 



