756 MANUAL OF ZOOLOGY. 



The nearly-allied genus Cercolabes or Sphingurus is South 

 and Central American, and it is distinguished from the preced- 

 ing by the possession of a long prehensile tail. In fact, the 

 species of Cercolabes, like so many of the inhabitants of this 

 wonderful continent, are adapted for an arboreal life, instead 

 of being confined to the ground. 



Fam. 6. Octodontidce. This family includes a large number 

 of Rodents which are principally South American and African 

 (Octodon, Echimys, Ctenomys, &c.) The best -known species 

 is the beaver-like Coypu (Myopotamus coypus) of South Ame- 

 rica, in which the hind-feet are webbed, and the tail is long 

 and rounded. It inhabits burrows in the sides of streams, and 

 it leads a semi-aquatic life. 



Among the other Octodontidce, the species of Octodon live in South Ame- 

 rica, and are rat-like Rodents, with short tufted tails, the molars being, 

 typically, of a simple type. In Ctenomys, also South American, the toes 

 of the hind-feet carry laterally a sort of comb of bristles. The Spiny Rats 

 (Echimys) are found in the West Indies and in Africa, and have the hair 

 mixed with fine spines, while the molars have complicated enamel-folds. 

 Petromys is an African type. 



Fam. 7. Chinchillida. This family includes some South 

 American Rodents, of which the true Chinchillas (Chinchilla] 

 are the best known. They are small, squirrel-like, nocturnal 

 animals, with large ears, and excessively soft fur, strictly ter- 

 restrial in their habits, and having the hind-legs considerably 

 longer than the fore-legs. The Alpine Viscachas (Lagidium) 

 live on the Andes up to heights of 16,000 feet; and the Vis- 

 cacha of the plains (Lagostomus) inhabits the South American 

 pampas. 



Fam. 8. Castor ida. The best-known example of this family 

 is the beaver (Castor fiber). The distinctive peculiarities of 

 the family are the presence of distinct clavicles, the posses- 

 sion of five toes to each foot, and the fact that the hind-feet 

 are webbed, adapting the animal to a semi-aquatic life. 



The Beaver is a large Rodent, attaining a length of from 

 two and a half to three feet. Naturally it is a social animal, 

 living in societies, and this is still the case in America,* but in 

 northern Europe and Asia, where the animal has been much 

 hunted, it leads a solitary life. When living in social commu- 

 nities the beavers build dams across the rivers, as well as habi- 

 tations for themselves, by gnawing across the branches of trees 

 or shrubs, and weaving them together, the whole being after- 

 wards plastered with mud. There is no doubt but that the 



* The American Beaver is sometimes considered to be a distinct species 

 '-(Castor- Canadensis], 



