372 



INTEODUCTION TO ZOOLOGY. 



Skeleton. — By far the greater number of the animals be- 

 longing to this class move on the ground by the action of 

 four feet, from which circumstance the name quadruped has 

 been restricted to them. It is occasionally vised in a more 

 general sense, as synonymous with the scientific term Tnam- 

 malia. The outline of the skeleton conveys, in most cases, 

 an idea of that of the body ; but occasionally, as in the hump 

 of the Camel {Fig. 290), there exists in the living animals 



Id 



Fig. 290,— Skeleton of Camel.* 



some peculiarly striking feature, which is not represented in 

 the bony framework. The hump, in the present instance, 

 consists of fatty tissue, and is well known to diminish in size, 

 and nearly to disappeai" when the animal is exposed to long- 

 continued privation. 



The possession of four feet used for the purposes of loco- 

 motion, though general in the mammaha, is by no means 



* FifT. 290.— Skeleton of the Camel on a black ground, exliibiting an outline of the 

 animal; re, cervical vertebra?; n/, dorsal vertebise; r/, Imnb.ir vertebra; r,?. sacral 

 vertebra;; rjr, caudal vertebrae ; 6, ribs; o, scapula; A, humerus; cu, bone of forearm ; 

 ca, can)us; mc, metacarpus; ph, phalanges; fe, lemur; ro, patella; ti, tibia; la, tarsus; 

 mt, metatarsus. In Jig. i91, the correspouding parts are indicated by the same letters as 

 in/?. 290. 



