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Show 1880.] DENTAL CHARACTERS OF THE CANIDAE. 261 differs from that of other Canidae and approaches the characters of the same tooth in the Viverridae and, especially, in the Procyonidae. It is obvious that, in all these features, Otocyon represents a lower term in the series of the Alopecoids than C. cinereo-argenteus and C. velox ; and although the interval between these and Otocyon is as wide as that between C. velox and C. vulpes, there would be no reason for separating Otocyon from the rest of the group were it not for the extraordinary excess in the number of molar teeth. Ot these there are four on each side above in one specimen, three in the others, four on each side below in all. So far as any conclusion can be drawn from this limited number of examples, therefore, it would appear that the presence of the fourth upper molar is exceptional; and that the dentition is tending towards a higher type by its suppression. The crowns of the hindermost upper molars, in the one specimen in which they are shown, are of a triangular shape, the base of the triangle corresponding with the two distinct external cusps. On the inner side only one cusp remains. The crown of the small fourth lower molar exhibits two well-developed cusps, of which the outer is rather the smaller. These apparently represent the anterior cusps of the other molars, as the posterior pair of cusps are proportionally smaller than the anterior pair in the third molar. 10. The facts now adduced appear to m e to permit of the arrangement of the Canidae hitherto considered in the following manner:- CANID^E. I. Molars f*f. A. Alopecoids. B. Thooids. a. Macrodonts. Ex. C. argentatus. Ex. C. lupus. C. vulpes. G. aureus. b. Microdonts. a. Mandible nonlobate. Ex. C. caama. Ex. C. azaree. C. zerda. C- vetulus. /3. Mandible lobate. Ex. C. littoralis. Ex. C. cancrivorus. II. Molars4^. 4.4 C. Otocyonoids. Otocyon. It will, however, be readily understood from what has already been said, that it is not intended to suggest the possibility of sharply separating the macrodont from the inicrodont forms, or those with lobed mandibles from those with mandibles of the ordinary character. On the contrary, they pass into one another ; while the lower lhooids, |