TONGUE IN BIRDS. 183 



and in poultry these are well developed. There are four 

 salivary glands. The lingual gland is situated by the side 

 of the tongue, and corresponds by its position, as well as 

 by its structure, with the sublingual in mammals. A pair of 

 glands is found behind the symphysis of the two lateral 

 parts of the lower jaw, the secretion being poured into the 

 mouth in the median line immediately before the tongue. 

 This pair of glands, according to Cuvier, is the sublingual. 

 Another gland is found on each side before the anterior 

 segment of the lateral horn of the hyoid bone, which in the 

 goose opens at once by several orifices. In the cock and 

 some other birds it has a long excretory duct^which opens 

 before the tongue and behind the last mentioned pair of 

 glands. There is a fourth gland found immediately beneath 

 the skin near the commissure of the jaws, which on each side 

 opens by several orifices into the mouth. 



Tongue. The tongue of birds is formed principally by the 

 middle anterior portion of the hyoid bone. It contains, besides 

 some weak muscular fibres, a greater or less proportion of fat 

 and cellular tissue. The tongue, however, varies more in birds 

 than in any other of the divisions of vertebrate animals. In 

 poultry it is triangular, pointed, smooth, cartilaginous, and 

 destitute of papillse except at its root ; while its firmness pre- 

 vents it from being injured by the hard and pointed substances 

 on which they live. In the duck tribe it is fleshy and large, 

 while the hyoid bone entering into it is of considerable size, 

 and terminates in front by a cartilaginous portion. In all the 

 duck tribe there are rigid hairs on the side of the tongue, 

 while in many there are ranges of osseous laminae. In the 

 swan the tongue is covered with stiff hairs, osseous plates, and 

 fleshy papillas. The joint resembling a ginglymus in the hyoid 

 bone is particularly remarkable in poultry. Besides the ante- 

 rior cartilaginous part of the tongue, there is an osseous part 



