226 



FIRST LESBOm IN ZOOLOGY. 



the trunk. Moreover, the cat catches a mouse or bird by 

 striking at it with its outstretched claws. Hence, the 



Wia 23t.— Side-view of cat's brain. F, frontal lobe; 7", temporal lobe; o!, olfac- 

 tory lobe; m, medulla oblongata; cb, cerebellum; v, pons Varolii; S, sylvian 

 fissure. 



shoulder-joint is very free, allowing the fore-leg to be ro- 

 tated in all directions. Fig. 333 shows the shape of the 

 claws, and how they are extended 

 and retracted. When the elastic 

 ligament passing from above the 

 root of the claw downward and 

 backward to the end of the second 

 phalanx is contracted, the claw is 

 withdrawn; but when the liga- 

 Fio. 232.— Claws of Se cat or ment is relaxed, and the long 

 tE^stro^g %rment*!,^Bi'^ciaw flexor tendon on the under side of 



Eeta^^IZ'b^l*soSTis*the toe is, with its muscle, con- 

 stretched out. tracted, the claw springs out. The 

 cat is a flesh-eater, and its powerful jaws, armed with sharp, 

 knife-like teeth, moved by powerful chewing muscles, 

 enable it to tear apart the body of its prey and swallow its 

 flesh piecemeal. 



But the cat is neither the highest nor lowest type of 

 mammalian life. It does not stand alone, but is only a 

 single link in the chain of mammalian life. And in order 

 to fully understand what a mammal is, we must glance at 

 the leading types or examples of the class. 



We shall see that the different groups vary greatly in 



