Skull, length over 210 mm. Skull, length of the palate 120 mm. Upper dentition, length the inc. 1 to m. 3 120 mm. Diameter of the palate opposite inc. 3 37 mm. Diameter of the palate opposite m. 3 75 mm. Height of mandible under m. 1 33 mm. [Illustration: Fig. 67. M. imbricatus—½ natural size; _A_, upper dentition; _B_, lower dentition after Ameghino.] [Illustration: Fig. 68. E. latirostris, palatal view, after a photograph of the type—½ natural size; the cross hatched area represents matrix not yet removed.] =Eurygeniops= Ameghino Eurygenium Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 655. Eurygeniops Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 464. The name first given this genus was found to be preoccupied, and therefore changed. It is a clear cut genus, differing from the others in the family in the expansion of the front of the muzzle, and by the heavy broad character of the skull. =Eurygeniops latirostris= Ameghino E. latirostris Amegh., loc. cited above. This is the type species and is based on a muzzle which has never been figured, but which I figure, the drawing being made from a photograph taken by Professor Scott and kindly furnished me. The characters of the species are those of the genus, with the following measurements for specific determination, quoted from Ameghino: Palate, length 130 mm. Palate, width between incisors 3 41 mm. Palate, width between premolars 2 33 mm. Palate, width between molars 3 56 mm. Upper dentition, length from pm. R. to m. 3 82 mm. Upper premolar 4, length 11 mm. Upper premolar 4, width 19 mm. =Eurygeniops normalis= Ameghino E. normalis Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 466. This second species is described as being much smaller than the preceding, the length from pm. 4 to molar 3 being 65 mm. CHAPTER VII LEONTINIDAE This family was established to include a group of large, heavily built ungulates, not unlike rhinoceroses in form, which have rooted teeth, the molars being similar to those of _Rhinchippidae_, _i. e._, composed of a wall and an anterior and posterior lobes, but with the cristae either lacking or little developed; and with the second upper, and the third lower incisors developed into tush-like caniniform teeth. Two genera are especially abundant, _Leontinia_ of the Deseado beds, and _Colpodon_ of the Colpodon beds, the former with the formula 3 1 4 3 -------, 3 1 4 3 the latter with 3 0 4 3 -------. 3 0 4 3