THE GALLINACEOUS GROUP. 25 



the purpose of mastication ; yet we are not 

 thence to infer that the teeth in such jaws are 

 useless, even although we have proof that the 

 gums do the business when the teeth are gone. 

 If pebbles are of use, which we may reasonably 

 conclude they are, birds have an advantage 

 over animals having teeth, so far as pebbles are 

 always to be found, while the teeth are not I'e- 

 newed. If we constantly find in an organ, sub- 

 stances which can only be subservient to the 

 functions of that organ, should we deny their 

 use, although the part can do its office without 

 them ? The stones assist in grinding doM'n the 

 grain, and, by separating its parts, allow the 

 gastric juice to come more readily in contact 

 with it." 



This we believe to be the true theory, — the 

 pebbles assist in crushing the grain, and at the 

 same time prevent it from consohdating into 

 a thick, heavy, compacted mass, which would 

 take a far longer time in undergoing the 

 digestive process, than when separated and 

 intermingled with the pebbles. 



The gallinaceous birds are very prolific, and 

 most are polygamous. The nest is, as a rule, 

 made upon the ground; the young are hatched 

 covered with down, and in a few hours are 



