308 



ZOOLOGY. 



ployed by the bird as instruments of prehension, vary exceed- 

 ingly in their character, according to the nature of the bird, the 

 food it lives on, and the prey it attacks. The superior man- 

 dible is so articulated with the cranium as to admit of motion in 

 the cranium, independent of the lower jaw, which never occurs 

 in mammals ; and the inferior, instead of being articulated 

 directly with the cranium by means of condyles, is connected 



Sacrum. Scapula. Humerus. 



Coccyx 



wain vw^ // m A'^Bii MI i/ m M/O^LMT/^A m 



ClaTicle. 



^ _.r~=-_ _,.= Sternum. 



Tibia. 



Tarsus 



Fig. 283. Skeleton of the Goeland. Black-headed Gull. 



therewith through the intermedium of a distinct bone, called 

 tympanic or os quadratum, generally considered to be a 

 portion of the temporal bone (the osseous meatus), and remain- 

 ing distinct throughout life. Moreover, each branch of the 

 lower jaw is composed of two segments, and it is by a fossette 

 that it articulates with the tympanic bone. 



