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Show 1895.] SOUTH-AMERICAN MARSUPIAL. 875 always considered as of family rank. It forms, therefore, among existing Marsupials a peculiar Family, and one which in America represents the Diprotodonts of Australia, just as the Didelphyidee do the Polyprotodonts. But turning to extinct Marsupials, the allies of Ceenolestes are readily found. For among the large numbers of fossils from the Santa Cruz beds of Patagonia described during the last few years by Senor Florentino Ameghino, of La Plata, there are some which so closely resemble Ceenolestes that no one can have the slightest doubt as to their being really related to it. These are the Epanorthidee and Decastidce of Ameghino, and, rather farther removed, the Abderitidee of the same author. Tbe last-named have a hypertrophied trenchant last lower premolar, and may for the present be put on one side. The other two, however, which contain, according to their describer, some 13 genera in all, show a dentition which cannot be distinguished from that of Ceenolestes in any character of family importance. Indeed, I fail, no doubt from only having descriptions and figures instead of actual specimens, to understand why Senor Ameghino distinguishes them from each other. But as the earliest named family, the Epanorthidee, contains some of the forms most closely allied to Ceenolestes, we may safely ignore for the present the Decastidce, and speak of the fossil allies of Ceenolestes simply as Epanorthidee. Further, after a careful examination of the characters of the different fossil genera, I am prepared to say that Ceenolestes is not only allied to, but actually falls into the Family, so that the name Epanorthidee must be used for its recent as well as fossil members. The best account of the fossil Epanorthidee is contained in a paper by Ameghino *. published in 1893, and giving a full list of all the genera and species described up to that date, with woodcuts of many of their jaws and teeth. Of these woodcuts I have ventured to copy two (see PI. L. figs. 8 & 9), those of the lower jaws of Decastis columnaris (p. 341) and Par epanorthus minutus (p. 350), which will show the exceedingly close alliance of Ceenolestes with those long-extinct Patagouian Marsupials. Again, in the figures of Epanorthidee given on plate i. of the same author's fine work of 1889 2, several agree very closely with Ceenolestes, notably the upper molar of Epanorthus lemoinei, drawn fig. 14, which shows very well the quadricuspid three-rooted character of the upper molars of Ceenolestes. The exact geological age of the beds in which Epanorthus and its fossil allies have been found is still under discussion, and I do not venture to express an opinion on the subject. Ameghino has called them Middle Eocene, Lydekker Oligocene or early Miocene. Further surveys will no doubt some day settle the point, but it is 1 " Enumeration synoptique des especes de Mammiferes fossiles des formations eocenes de Patagonie," Bol. Ac. Cordoba, xiii. p. 259 (1893). 2 • Mamiferos fosiles de la Republica Argentina.' Text and Atlas, fol. |