492 ANATOMY OF HYDROCHOERUS CHAP. 



(or Carpi ncho) being the greatest of existing Rodents. The ears are 

 well developed. The toes are commonly reduced, and the members 

 of this family possess only a rudimentary tail. The hair though 

 rough is not spiny. Other characters had best be deferred until 

 the several genera are treated of. We shall begin with the giant 

 of the family, the genus Hydrochoerus. This genus contains but 

 a single species, H. capybara, of South America. It reaches a 

 length of some 4 or 5 feet. The ears are not large ; the tail is 

 completely absent. The fore-feet are four-toed, the hind-feet 

 three-toed; the digits are webbed, though not to a very great 

 degree, and the nails have the appearance of hoofs. There are 

 fourteen dorsal vertebrae ; the clavicle is absent. In the skull 

 the paroccipital processes are of great length. The infra-orbital 

 foramen is large. The most remarkable fact about the teeth is 

 the great size of the posterior molar of the upper jaw ; it has 

 fourteen folds of enamel, more than all the anterior teeth possess 

 collectively. The incisors are white and grooved in front. The 

 measurements of the alimentary tract as given by Tullberg are : small 

 intestine, 4350 mm.; caecum, 450 mm.; large intestine, 1500 mm. 

 The Capybara or Carpincho is largely aquatic in its habits. 



FIG. 241. Patagonian Cavy. Dolichotis patachonica. x^\. 



Their " favourite locality," writes Mr. Aplin, 1 " is a broad laguna 



"Field Notes on the Mammals of Uruguay," Proe. Zool. Soc. 1894, p. 297. 



