_Abrocoma Cuvieri._ ] [Illustration: _Mammalia Pl. 30._ _Didelphis crassicaudata._ ] [Illustration: _Mammalia Pl. 31._ _Didelphis elegans._ ] [Illustration: _Mammalia Pl. 32._ _Didelphis brachyura._ ] [Illustration: _Mammalia Plate 33._ _G.R. Waterhouse. & C.M. Curtis_ ] [Illustration: _Mammalia Plate 34._ _G.R. Waterhouse_ _J. Swaine_ ] [Illustration: _Mammalia Pl. 35._ _Drawn by C. H. Curtis._ ] ----- Footnote 1: The palatine foramina are accidentally omitted—see description. Footnote 2: Voy. Amer. Merid. t. 8. Footnote 3: See his memoir “Sur quelques anomalies du système dentaire dans les mammifères,” published in the “Annales Françaises et Etrangères d’Anatomie et de Physiologie,” No. 6, pl. IX. fig. 2. Footnote 4: Magazine of Zoology and Botany, No. 12. Footnote 5: “Annales des Muséum d’Histoire Naturelle,” tom. xv. p. 176. Footnote 6: Journal Historique d’un Voyage fait aux Iles Malouines, tom. ii. p. 459. Footnote 7: Azara has not described this animal, which circumstance alone would render it probable that it is not an inhabitant of Paraguay or La Plata. The two Foxes mentioned by him are the Aguará-guaza, (_Canis jubatus_, Auct.) a very large kind of fox (a strangely exaggerated description of this animal is given by Falkner) of which I could not obtain a specimen; and the Aguará-chay, or _Canis Azaræ_. Footnote 8: Molina, Compendio de la Historia del Reyno de Chile, vol. i. p. 330 and 332. Footnote 9: I am indebted to Mr. Ogilby, who visited the Prince’s collection, for a description from the specimens of _C. Azaræ_ therein preserved. In this description the tip of the tail is said to be black. Footnote 10: Considering the great difference of climate and other conditions between the hot and wooded country of Paraguay, and the desolate plains of Patagonia, one is led to suspect that the _Canis Azaræ_ of La Plata and Patagonia, which wanders about by day, and inhabits burrows instead of heaps of straw, may turn out to be a different species from the Agouará-chay of Azara, which is nocturnal in its habits, and lives in thick coverts. Footnote 11: In measuring the species of Mammalia, I almost invariably, when wishing to give the length, measure from the tip of the nose _along the curve of the back_ to the root of the tail. In the Ruminantia of course this plan is not desirable, but in other Mammals I have found it most convenient. If we take a Cat, for instance, and curve the body in whatever way we please, we find the length (taken in the way just mentioned) always the same. Whereas, if we take a straight line (as many naturalists do) the length will vary according to the position of the animal. Footnote 12: