Atlas, greatest length 86 mm. Atlas, greatest width 170 mm. Axis, length of centrum and odontoid process 132 mm. Axis, length of odontoid process 34 mm. Axis, width across anterior cotyles 98 mm. Cervical 3, length of centrum 66 mm. Cervical 3, width of posterior end of centrum 55 mm. [Illustration: Fig. 74. Atlas seen from below—¼ natural size.] [Illustration: Fig. 75. Axis and cervical vertebra, No. 3—¼ natural size.] While there are other vertebrae in the collection, which probably belong to this species, I have not cared to make the association without some evidence of a definite character. However, in the case of a fore limb, which was found fairly near one of the skulls, is of proper size, and because this humerus occurs with something like the frequency of the skulls, I have been convinced that it belonged to this species, and so described it under the genus. This specimen consists of the two humeri, the radius and the ulna, No. 3328. Humerus, greatest length 314 mm. Humerus, diameter of head 77 mm. Humerus, transverse diameter of the shaft 43 mm. Humerus, width of distal end 116 mm. The ulna lacks some 60 mm. in the middle of the shaft, but when fitted to the radius its length can readily be obtained. The radius is considerably weathered so that measurements of the distal end are only approximate. Ulna, length over all 430 mm. Ulna, transverse diameter of distal end 58 mm. Radius, length over all 310 mm. [Illustration: Fig. 76. Right humerus from the posterior side—¼ natural size.] [Illustration: Fig. 77. Right ulna from external side—¼ natural size.] [Illustration: Fig. 78. Proximal end of right radius—¼ natural size.] =Leontinia garzoni= Ameghino L. garzoni, Amegh., 1896, Bol. Inst. Geog. Argen., t. 15, p. 650. L. garzoni, Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 474. We were not fortunate enough to find this species, but as described by Ameghino it is about 60 per cent. of the size of _L. gaudryi_. The type is a lower jaw, for which the following figures are given: Lower dentition, length from pm. 1 to m. 3 120 mm. Lower dentition, length from pm. 1 to pm. 4 45 mm. Lower dentition, length of pm. 4 15 mm. Lower dentition, length of m. 3 39 mm. =Ancylocoelus= Ameghino Ancylocoelus Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 652. Ancylocoelus Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 475. Rodiotherium Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 653. Rodiotherium Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 476.