DIGESTIVE SYSTEM OF BIRDS. 



155 



77 



tubules, opening separately upon the mucous membrane of the 

 mouth, along the sides of which cavity they are situated. They 

 pour out a viscid mucus, and 

 are the only traces of a sali- 

 vary system met with in this 

 bird. 



In many other birds, and 

 especially in the Scratching, 

 Wading, and Smmming Or- 

 ders, glands of the conglo- 

 merate structure are found 

 beneath the lower jaw, an- 

 swering to the submaxillary 

 glands of quadrupeds. 



In the Goose they occupy 

 the whole of the anterior part 

 of the space included by the 

 rami of the loAver jaw, being 

 of an elongated form, flat- 

 tened and closely united to- 

 gether at the middle line. On 

 either side of this line the 

 mucous membrane of the 

 mouth presents internally a 

 series of pores, each of which 

 is the terminal orifice of a 

 distinct o-land or asc^reffate of 

 ramified ducts. 



A third and liigher form of 

 salivary gland, in which the 

 secretion of the conglomerate 

 mass is conveyed into the 

 mouth by a single duct, is 

 found in the Woodpeckers 

 and some species of the Ka- 

 pacious Order. In the latter 

 birds these glands are termed, 

 from their situation, anterior 

 palatine : in the Piece they 

 correspond to the parotid and 

 sublingual of Quadrupeds. 



The sublino'ual o^lands of 

 the Woodpecker, fig. 77, ?, h, are of extraordinary size, extcndim 



Tongue and salivary glands. Woodpecker. 



