6 MANUAL OF ZOOLOGY 



Cynaelurus are placed together in the family Felidce. 

 Similarly the Civets and Mongooses form the family 

 Viverridce ; the Dogs, Wolves, Jackals, Foxes, &c., the 

 family Canidce ; Bears, the family Ursidce ; and so on. 



All the foregoing animals have sharp teeth adapted to a 

 flesh diet, and their toes are armed with claws. They 

 therefore differ fundamentally from such animals as Sheep, 

 Deer, Pigs, and Horses, which have flat teeth adapted for 

 grinding vegetable food, and hoofed feet. The differences 

 here are obviously far greater than those between any two of 

 the families mentioned above, and are emphasised by 

 placing the flesh-eaters in the order Carnivora, the hoofed 

 animals in the order Ungulata. In the same way gnawing 

 animals, such as Rats, Mice, and Beavers, form the order 

 Rodentia ; pouched animals, such as Kangaroos and 

 Opossums, the order Marsupialia ; and so on. 



Carnivora, Ungulata, Rodentia, Marsupialia, &c., 

 although differing from one another in many important 

 respects, agree in the possession of a hairy skin and in the 

 fact that they^all suckle their young. They thus differ from 

 Birds, which have a covering of feathers, and hatch their 

 young from eggs. The differences here are considerably 

 more important than those between the orders of quadrupeds 

 referred to, and are expressed by placing the latter in the 

 class Mammalia, while Birds constitute the class Aves. In 

 the same way the scaly, cold-blooded Lizards, Snakes, 

 Tortoises, &c., form the class Reptilia ; the slimy-skinned, 

 scaleless Frogs, Toads, and Salamanders the class Amphibia ; 

 and the finned, water-breathing Fishes the class Pisces. 



Mammals, Birds, Reptiles, Amphibians, and Fishes all 

 agree with one another in the possession of red blood and 

 an internal skeleton an important part of which is the 

 backbone or vertebral column and in never having more 



