In its general form the Capybara is more pig-like than any of its relatives, and, indeed, its generic name, _Hydrochœrus_, Water-pig, recalls this resemblance, and at the same time intimates its aquatic habits. Its coat is composed of long and coarse hairs, often five or six inches long on the hinder parts, of a reddish-brown colour above, and a dirty brownish-yellow beneath. It is distributed over the whole eastern part of South America, from Guiana southwards to the Rio de la Plata, and ranges westwards into the lower parts of Peru and Bolivia. [Illustration: MOLARS OF THE CAPYBARA.] The Capybaras frequent the borders of the lakes and rivers, with which all this part of the South American continent abounds, and, according to Mr. Darwin, they used to frequent the islands in the mouth of the La Plata, where the water is quite salt. In this part of America they are called “Carpinchos.” They never wander far from the water-side, and show a marked preference for the larger rivers, among the reeds and other plants fringing which they take up their abode. In populous districts they seem to pass the day in concealment, coming forth in search of food only at morning and evening, but where they are less in danger of pursuit they come out freely in the day-time. Seen from a little distance when walking they have much the appearance of Pigs, but they lose this when they sit, like the other Cavies, on their haunches. When danger threatens they emit a short, sharp bark, and immediately plunge into the water, where they swim about with little more than the nostrils above the surface; but under pressing circumstances they can dive and swim for a considerable distance under water. When swimming, the female is said to take her young ones on her back. About Maldonado Mr. Darwin observed that the Capybaras were usually to be seen only three or four together, but they are more numerous and go in larger companies more in the interior of the country. They constitute the ordinary food of the Jaguar, and are also eaten by the Indians, although their flesh is said not to be very good. The female produces five or six young at a birth, but has only one litter in the year. The young follow their mother about at a very early age. SUB-ORDER II.--DOUBLE-TOOTHED RODENTS.