Pectinator spekii is the only representative of a genus not far removed from Ctenodactylus; it is a smallish Rodent, 6 inches in length, exclusive of a rather bushy tail nearly 3 inches long. It comes from Abyssinia. It has somewhat the appearance of a Squirrel, which is heightened by the fact that when sitting the tail is arched over the back; when running the tail is carried out straight. There are only four toes visible externally on both fore- and hind-limbs, but pollex and hallux exist in the skeleton, with a single phalanx each. There is only a single pair of mammae, and in correspondence with this but two or three young are produced at a time. The hind-feet have bristles very much like those of Ctenodactylus. The molars, however, are 4/4. There are twelve ribs, of which six reach the sternum. The latter is made up of six pieces, and the manubrium in its breadth anteriorly suggests that of the Vizcachas. The clavicles are present.[[348]]
Fig. 240.—Carpincho. Hydrochoerus capybara. × 1⁄12.
Fam. 3. Caviidae.—This family, which includes the Cavies and the Capybara, is entirely South American and West Indian in distribution. It embraces animals of fair to large size, the Capybara
(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, 4350 mm.; caecum, 450 mm.; large intestine, 1500 mm.
Fig. 241.—Patagonian Cavy. Dolichotis patachonica. × 1⁄10.
The Capybara or Carpincho is largely aquatic in its habits. Their "favourite locality," writes Mr. Aplin,[[349]] "is a broad laguna
in the river, furnished with open water, and also beds of 'camelotes,'—a sloping open grassy bank on one side, where the Carpinchos can lie in the daytime in the cooler weather, sleeping and basking in the sunshine; on the other a low shelving bank, clothed with 'Sarandi' scrub growing out into the black reeking mud and shallow water beyond." They always take to the water when alarmed, at a rate and with a gait which reminded Mr. Aplin of a Pig. When in the water they swim slowly with the upper part of the head, including nose, eyes, and ears, above the surface. But they can dive for a considerable time and distance, and baffle their enemies by seeking the shelter of a mass of water-plants, and lying there with their noses only just above the surface.
The genus Dolichotis[[350]] has long ears, and generally resembles a rather long-legged Hare in appearance. The front-feet are four-toed, the hind three-toed. The Patagonian Cavy, as this animal is called, has twelve dorsal vertebrae, and rudimentary clavicles.[[351]] The paroccipital processes are long; the incisors are white, and are not grooved in front. The sternum has six pieces, and seven ribs reach it.