For such a heavy animal, the humerus is extraordinarily long and slender. The sessile head is strongly compressed from side to side, very convex, and much larger than the glenoid fossa, its articular surface extending onto the base of the greater tuberosity. This tuberosity is heavy and thick, but does not project above the head. The powerful deltoid ridge extends from the tuberosity two-thirds of the way down the shaft. The shaft is unusually slender. Distally it expands laterally to make the two large epicondyles, of nearly equal size. The trochlea is relatively narrow, the internal surface being the narrower, and rising to a high margin; while the external portion is wider, rounded, and has a low margin. The supratrochlear fossa is moderately deep, the anconeal fossa somewhat deeper, but there is no connecting foramen. Gaudry[17] figures a radius and ulna, both relatively long bones, and closely apposed; so that there was no possibility of a rotary motion of the forearm. The proximal end of the radius is expanded, so that its articular surface is in contact with the full width of the humeral trochlea on the anterior side. Below, the bone contracts to a moderately slender shaft, and then expands distally into a heavy club-like distal end. The ulna has a short but heavy olecranon process, with a prominent coronoid process. The sigmoid notch is shallow, but the articular surface expands on both sides, so that it covers the full width of the humeral trochlea on the posterior side. Distally the ulna is not so heavy as the radius. [Footnote 17: Anal. Palaeontologie, t. 1, p. 5, 1906.] Under the name _Pyrotherium romeri_, Ameghino[18] figures a carpus and metacarpus, which Tournier[19] however assigns to _Parastrapotherium_, probably _P. herculeum_; and figures a carpus and metacarpus of the same type, but smaller, which he attributes to _Parastrapotherium_. I, however, can not see how such a small foot can belong to so large an animal, and feel that, until evidence of direct association is given, it is best not to consider these feet as belonging to _Parastrapotherium_, but rather to _Pyrotherium_. [Footnote 18: Bol. Inst. Geog. Argen., t. 18, p. 442, fig. 25, 1897.] [Footnote 19: Bul. Soc. Geol. France, ser. 4, t. 5, p. 305, 1905.]