492 ANATOMY OF AWYDROCHOZRUS CHAP. 
(or Carpincho) 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, 4550 mm.; caecum, 450 mm.; large intestine, 1500 mm. 
The Capybara or Carpincho is largely aquatic in its habits. 
Fic. 241.—Patagonian Cavy. Dolichotis patachonica. x 35. 
ae 
Their “favourite locality,” writes Mr. Aplin,’ “is a broad laguna 
1 «Field Notes on the Mammals of Uruguay,” Proc. Zool. Soc. 1894, p. 297. 
