Physornis fortis Ameghino.

P. fortis Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 576.

Under this specific name Ameghino describes a part of the lower jaw 150 mm. long which he says equals in size Phororhacus longissimus, and differs only in the greater convexity of the mandible. Our specimen is a femur, apparently of the same bird, being of the type of Phororhacus and about the size of P. longissimus; so I have placed it in this species.

This femur is of large size, moderate length, and has a shaft subcylindrical in section. The distal end is expanded and the condyles are flattened, the inner one being the wider, the outer condyle being narrower and the external margin projecting to make a high ridge. The pit on the posterior side of the shaft just above the condyles is unusually deep and of large size. On the anterior side there extends from either condyle a low marginal ridge which soon fades into the contour of the shaft. Between these ridges there is a wide shallow furrow which also loses itself above in the convex surface of the shaft.

Fig. 149. Right femur, back view—½ natural size.

Measurements
Femur,least diam. of the shaft58 mm.
Femur,diameter across the condyles  148 mm.