Lagostomus trichodactylus, _Brooks_, Transactions of the Linnean Society, vol. xvi. p. 95, Pl. 9. La Vizcache, _Azara_, Essais sur l’Histoire Naturelle des Quadrupedes de la Province du Paraguay, vol. ii. p. 41. Trad. Franc. Vischacha, _Moyen_, Acta Academiæ, _c. l. c._ Naturæ Curiosorum, Tom. xvi. pars 2, p. 584. Habitat, La Plata. “I will not repeat what I have said about the habits of this animal in my Journal, as it is merely a corroboration of Azara’s account. According to that author, the Bizcacha is not found north of 30°; and its southern limit occurs in the neighbourhood of the Rio Negro in 41°. Where the plains are gravelly, it is not abundant, but (differently from the _Cavia Patagonica_,) it prefers an argillaceous and sandy formation, such as that near Buenos Ayres. The Bizcacha abounds over the whole Pampas, even to the neighbourhood of Mendoza, and there it is replaced in the Cordillera by an Alpine species. Of the latter animal, I saw one seated on a pinnacle at a great height, but I could not obtain a specimen of it. Azara[42] has remarked that the Bizcacha, fortunately for the inhabitants of Banda Oriental, is not found to the eastward of the Rio Uruguay; and what makes the case more remarkable is, that although thus bounded by one river, it has crossed the broader barrier of the Parana, and is numerous in the province of Entre Rios. I was assured by a man, whose veracity I can perfectly trust, that these animals, quasi canes, post coitum adnexi sunt.”—D. FAMILY—CAVIIDÆ. KERODON KINGII. Kerodon Kingii, _Bennett_, Proceedings of the Zoological Society of London for 1835, p. 190. Habitat, Patagonia. “The Kerodon is common at intervals along the coast of Patagonia, from the Rio Negro (Lat. 41°) to the Strait of Magellan. It is very tame, and commonly feeds by day: it is said to bring forth two young ones at a birth. At the Rio Negro it frequents in great numbers the bottoms of old hedges: at Port Desire it lives beneath the ruins of the old Spanish buildings. One old male killed there weighed 3530 grains. At the Strait of Magellan, I have seen amongst the Patagonian Indians, cloaks for small children made with the skins of this little animal; and the Jesuit Falkner says, that the people of one of the southern tribes, take their name from the number of these animals which inhabit their country. The Spaniards and half-civilized Indians, call the Kerodon, ‘conejos,’ or rabbit; and thus the mistake has arisen, that rabbits are found in the neighbourhood of the Strait of Magellan.”—D. 1. CAVIA COBAIA. Cavia Cobaia, _Auct._ Habitat, Maldonado, La Plata, (_June_.)