184 PHYSIOLOGY AT THE FARM. 



articulated with the hyoid bone. The median line even is 

 osseous from the point of the hyoid bone to the anterior ex- 

 tremity of the tongue, whence their tongues are but little 

 movable ; neither are they bifurcated as in some other birds, 

 or apt to change their form. 



Pharynx. The pharynx conforms to the dimensions of the 

 neck, and is for the most part both long and of considerable 

 size ; its circumference is generally much the same as that of 

 the stomach. The internal membrane is smooth, with a few 

 doublings ; the muscular coat is very thick. In the pharynx 

 of birds there are no special constrictors, the muscular coat 

 being merely^ continuous with the corresponding coat of the 

 gullet. 



Gullet. In granivorous birds the gullet is a little inclined to 

 the left side of the trachea, and terminates at the bottom of the 

 neck in a large sac, the ingluvies or crop, termed by the French 

 idbot. It has the same structure as the gullet, but is thinner. 



Crop. The crop in poultry is of a globular form, and is 

 placed at the fore part of the chest. The gullet terminates at 

 the upper or fore part of this sac, and issues again from its oppo- 

 site extremity ; thus the crop forms a cul de sac between these 

 two orifices. The crop belongs to other birds besides the gal- 

 linaceee ; for example, to diurnal birds of prey, and parroquets. 

 It has, however, comparatively, a considerable development in 

 gallinaceous birds, and among these particularly in the pigeon. 

 This pouch, however, differs entirely in the pigeon from its 

 character in other birds, both in respect to size and to the 

 peculiar mode in which it is constructed and placed, since in 

 the pigeon it is prolonged into two lateral halves, quite sym- 

 metrical, occupying a corresponding place on each side. 



Upon the inner side of the crop are numerous glands, with 

 very distinct orifices in the larger birds, which throw out a 

 liquor to assist in the solution of the food. These glands are 



