CAVY, a name common to several species of Rodents belonging to the family Caviche, all of which, at least in the wild state, are confined to the South American continent. They are small creatures, seldom exceeding a foot in length, burrowing in the ground, and feeding entirely on fruits and herbs. There are several species. (1.) The Patagonian Cavy (Dolithotispatagonica), larger than a hare, but somewhat resembling that rodent in external appearance, inhabits the dry sterile districts of Patagonia and La Plata, disappearing wherever the country becomes more humid. It is a shy creature, forming burrows in the earth, although in districts where the bizcacha is found, it is said to avail itself of the subterranean works of the latter. It feeds by day, roaming in search of food in small companies, " hopping," says Darwin, " one after the other in a straight line over the gravelly plain." Unlike other caries, its eyes, like those of the kangaroo, are protected from the glare of the sun by prominent eyelashes. It is covered with a long dense fur of a rusty colour, and has a short tail. It produces two young at a birth. (2.) The Restless Cavy (Carla aperea), found throughout Uruguay and Brazil, is supposed to be the wild form of the Guinea-pig of Europe. It is about 10 inches long, is destitute of a tail, and weighs a little over 1 it); its fur is long and of a nearly uniform greyish-brown colour. The aperea is rarely found in dry sandy localities, preferring marshes covered with aquatic plants, among which it lies concealed, feeding in the early morning and after sunset in the evening, but when the soil is dry it forms burrows like the other caries. It is said to live in societies of from six to eighteen individuals, to breed but once a year, and to have one or at most only two young at a birth. The Guinea-pig (Carla cobaya of some authors) was, according to the zoologists of the 16th century, unknown in Europe previous to the discovery of America, and there is little doubt that it was introduced from the southern division of that continent, the name of Guinea-pig being probably given by mistake for Guiana-pig. It differs, however, in many important respects from the wild aperea. It is somewhat larger, as might be expected in a cultivated form ; the colour of its fur is white, variegated with irregular patches of red and black. It perishes on the marshy soil which the other prefers ; it produces a numerous progeny three times a year; and what is more important still, the two forms do not couple together, a difference which among wild species is usually held as indicating generic distinctness. It appears, from the drawing of Aldrovandus, that the Guinea-pig had already attained its present variegated colouring fifty years after the discovery of America, a fact which has led to the supposition that it had been previously domesticated by the natives of South America. Mr Waterhouse, however, thinks it more probable "that some pretty variety had attracted the attention of the earliest European settlers in the New World, and given rise to its capture and domestication, more especially as the harmless disposition and pretty colouring of the common Guinea-pig appear to be the only claims of interest which are attached to it" (Yatural IIistory of the Mammalia, vol. ii.) It is a singularly inoffensive and defenceless creature, of a restless disposition, and greatly wanting in that intelligence which usually characterizes domestic pets, although it is said to show some discrimination. It is of no particular service to man, neither its flesh nor its fur being put to use, while the statement that its presence is sufficient to drive off rats and mice appears to be without foundation. It is exceedingly prolific, beginning to breed at the age of two months; the number of young varies, according to the age of the parent, from four to twelve. It has been calculated that a single pair of Guinea-pigs may prove the parent stock of a thousand individuals in a single year. (3.) The Bolivian Cavy (Carla bolivensis), found throughout the higher regions of Bolivia, usually at an elevation of 10,000 or 12,000 feet, is exceedingly shy, and lives in burrows, these in some districts being so numerous as to have completely undermined the soil. (4.) The Rock Cavy (Cavia rupest•is), distinguished by its short, blunt nails, is found in rocky situations throughout Brazil, and is much sought after for its flesh, which is considered a dainty by the Indians. (5.) The Southern Cavy (Carla australis), common along the coast of Patagonia, forms deep burrows, with several outlets, in sandy declivities, and is said to climb trees in search of the fruit on which it feeds.