Cavia, including the species C. porcellus, the Guinea-pig (which name is a corruption apparently of Guiana pig), has the same number of toes on its hind- and fore-feet as has the Capybara. The name applied to the wild stock whence our Guinea-pig is derived is the Restless Cavy. The fur is greyish; of the domestic animals the colour is too well known to need description.
Fam. 4. Dasyproctidae.—The genus Coelogenys includes but two species. C. paca, known as the "Spotted Cavy" or "Paca," has a brown body, with white spots like those of a Dasyure; it is one of the largest of Rodents, and has a quite short tail. The hand and foot are both provided with five digits; but the thumb is small, and in the foot the three middle toes considerably exceed the others in length. The hind-foot is practically three-toed. The fibula is not nearly so reduced as in Dolichotis. The skull of the animal is remarkable for the extraordinary development in breadth of the jugal arch, which is sculptured externally. There is a large cavity formed below, at the maxillary end of this huge
arch, by the curving inwards of the bone, which lodges a cavity continuous with the mouth. The palate has anteriorly a ridge on either side, and is thus divided from the sides of the face in a way which is not found[[352]] in the allies of Coelogenys. Clavicles are present. There are thirteen dorsal vertebrae. The incisors are coloured red in front. The animal is South American, and in that continent is limited to the Brazilian sub-region. This, the best-known species of Paca, is called the Gualilla by the natives of Ecuador; in the same district another form is met with which the natives term Sachacui (signifying Forest Cavy). It is very often the case that a different native name expresses a real specific difference; and to the latter form M. T. Stolzmann has given the name of C. taczanowskii.[[353]] This form, unlike the common Paca, which is fond of forests and low-lying ground in the neighbourhood of water, is alpine in habitat, living upon mountains of 6000 to 10,000 feet. It burrows in much the same way as its congener, and is greatly sought after as food, its meat possessing an "exquisite taste." It is pursued by dogs, by whose aid one of the two entrances to the burrow is guarded, and the creature is smoked out and killed with a stick.
The genus Dasyprocta, containing those Rodents known as Agoutis, is divisible into several species, apparently about twelve, all of which are, like the Pacas, confined to the Neotropical region. They have, however, a much wider range within that region, and occur as far north as in Central America and in some of the West Indian Islands. They are of rather smaller size than the Paca, and are without spots. The colour is of a golden brown in some forms, but usually has a freckled, grizzled, greenish kind of appearance. The tail is stumpy, the hind-limbs are distinctly longer than those of the Paca, and the two lateral toes have disappeared from the feet—a concomitant as it seems of the Agouti's greater powers of running. The three metatarsals are closely pressed together, and the foot is as it were on the way towards the highly-modified foot of the Jerboa. The fore-feet are, however, five-toed. The clavicle is rudimentary,[[354]] whereas it is well developed in the Paca. The skull has not the peculiar modifications of that of the last-mentioned type. The sternum has seven
pieces, and eight ribs reach it. A curious difference between this genus and the last is in the relative proportions of the regions of the intestine. The figures given by Tullberg for the two animals are—for Coelogenys, small intestine, 4800 mm.; caecum, 230 mm.; large intestine, 21,000 mm.;—for Dasyprocta aguti the same author gives: small intestine, 4200 mm.; caecum, 200 mm.; large intestine, 1000 mm. The Agouti, says Mr. Rodway,[[355]] is as wily as the Fox. "If chased he will run along the shallows of a creek to hide his scent from the dogs, or swim over and back again several times for the same purpose. He never runs straight when pursued, but doubles, often hiding until a dog has passed, and then making off in a different direction. Like the fox he has been hunted for a very long period, and, like Reynard, has grown wiser with every generation."
Fig. 242.—Agouti. Dasyprocta aguti. × 1⁄10.
Fam. 5. Dinomyidae.—The genus Dinomys of Dr. Peters[[356]] is a very little known and remarkable form from South America allied to the Capybara, the Chinchilla, and other South American Rodents. It is only known by a single example found wandering about a courtyard in a town of Peru. It is externally like, and of about the same size as the Paca, but has a hairy tail. The animal is four-toed and plantigrade; the ears are short, and the nostrils are
-shaped. It is usually regarded as belonging