Fig. 45.
Archaeophylus patrius
after Ameghino,
right upper dentition—
natural size.

A. patrius Amegh., loc. cit.

We found no specimen of this interesting type, but I give a diagram of Ameghino’s type, which shows the characteristics of the species and genus. The length of the premolar-molar series is 27 mm.

Eutrachytheridae Ameghino

The family consists of larger forms than the other families, and is characterized by the upper molars having the inflexion bifurcated, so that the teeth are at least incipiently three-lobed. I would place in the family the genera, Eutrachytherus, Argyrohyrax, and Isopoedrium.

Eutrachytherus Ameghino

Trachytherus Amegh., 1889, Act. Acad. Nac. Cienc. Cordoba, t. VI, p. 918.
Trachytherus Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 623.
Eutrachytherus Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 429.

This genus was first called Trachytherus, and when this was found to be preoccupied, changed to Eutrachytherus. Ameghino gives the dental formula as