MAMMALS THAT GNAW. 115 



by the animals themselves, which in former days absolutely swarmed on the 

 pampas. Consequently for years the estancieros have waged incessant war 

 agauist these Rodents, with the result that in the parts of Argentina which 

 have been longest under cultivation one may ride for miles without coming 

 across a warren. 



The two genera of this South and Central American and West Indian family 

 include a small number of relatively large, terrestrial Rodents, characterised 

 by the fore and hind-limbs being of nearly equal length, and 

 having their toes furnished Avith hoof-like claws, by the Agutis and 

 short or rudimental tail, the very imperfect collar-bones, the Paoas.— Family 

 broad palate, long incisors, and the partially rooted molars, Dasyproctidm. 

 in which the foldings of enamel form notches on the two 

 sides of the crowns. The agutis (Dasyprocta) are rather delicately built 

 animals, witli long limbs and three hind-toes, ranging from the confines of 

 Mexico to Paraguay, and represented by 

 a single outlying species in the West 

 Indies. On the other hand, the pacas 

 (Ccelogenys), which are found from Ecua- 

 dor to Brazil and Paraguay, are larger 

 and more heavily-built animals, with five 

 toes to the hind-feet, and further char- 

 acterised by the longitudinal rows of 

 light-coloured spots on the fur, and the 

 enormous hollow, bony capsules formed 

 by the expanded bones of the cheeks. 



Branick's paca (Dmomys), of which only pig^ m.-A.ovti (Dasyproda). 



a single specimen from Peru has hitherto 



been obtained, is distinguished from the Dasyproctldce by the cleft upper-lip, 

 somewhat long and bushy tail, the presence of four toes to each foot, and the 

 complete collar-bones ; and is accordingly regarded as the representative of a 

 separate family. 



The next of these South American families is that of the cavies, and includes 

 large or small heavily-built Rodents, with four front and three hind -toes, 

 rudimental or short tails, and the cheek teeth divided by 

 transverse folds of enamel into a number of thin plates The Cavies. — 

 lying parallel to one another. The typical representatives Family Caviidce. 

 of the family are the true cavies (Cavia), of which the 

 guinea-pig is a domesticated descendant, having assumed a coloration quite 

 different from the uniform olive-brown tint characteristic of its wild ancestors. 

 Quizes, as these animals are called in the Argentine, may be found not only 

 among aquatic plants in marshy districts, and skulking in the tufts of coarse 

 grass on the pampas, but also in the neighbourhood of human habitations, 

 where they will not unfrequently take up their residence under the floors of 

 outbuildings, whence they issue forth to feed at night. All the true cavies 

 are small and short-legged creatures, with no tail, and short ears ; but the 

 Patagonian cavy, representing the genus Uolichotis, is a much larger and 

 taller animal, measuring nearly a yard in length, and standing over a foot at 

 the shoulder, with tall ears and a short tail. An inhabitant of the open dis- 

 tricts of Patagonia and Argentina, the mara, as it is called by the natives, 

 much resembles a hare in its movements. Unfortunate!}', the spread of 

 cultivation has well-nigh exterminated this handsome Rodent from most parts 

 of the Argentine. Largest, not only among South American Rodents, but 



