Lagotis (Bennett), or Lagidium, a genus of the chinchilla family, having the following dental formula: incisors 2/2; molars 4/4-4/4 = 20. The incisors are sharpened, and each molar consists of three complete oblique plates. Skull arched posteriorly and above; the superior cellules of the tympanum are inconspicuous. All the feet are four-toed, the great toe being entirely absent; nails long and subfalcular; ears very long; tail long; fur soft but caducous. Of this genus there are two species, the L. Cuvieri and the L. pallipes, being, it is supposed, the viscacha of all the writers from Pedro de Cieca downward, who have declared that animal to be an inhabitant of the western or Peruvian slope of the Andes. It is about the size and color of the hare, which is wanting to the fauna of Peru, Chili, and Ecuador, and appears to be equivalent in those countries to that creature and to the rabbit, among which it has been classed by some writers, especially Lesson, in his Manuel, who has apparently confounded the eastern and western species, lagotis and lagostomus, and who gives it as the lepus viscaccia of Gmelin. This animal breeds among rocks and stony places, burrows in the ground, and is famous, if mortally wounded and not killed at once, for taking refuge in its burrow and dying within it, so as to be lost to its pursuers.
Its fur, which is longer and softer than that of the rabbit, has the peculiarity of falling out as soon as the animal is dead. This animal and the chinchilla are evidently connecting links between the hares and the squirrels, the first coming nearer to the hares, the latter to the squirrels.