Ameghino based this species on a portion of the mandible of an old individual with molars 1 and 2. Its chief distinction lies in its small size as compared with P. holmbergi. Gaudry assigned to this species some upper teeth. We found no specimens of this species. The following are the measurements of the type according to Ameghino.

Lower dentition,molar 1,length 31 mm.,width 16 mm.
Lower dentition,molar 2,length42 mm.,width21 mm.

Parastrapotherium martiale Ameghino

P. martiale Amegh., 1901, Bol. Acad. Nac. Cordoba, t. 16, p. 402.
P. superabile Amegh., 1901, Bol. Acad. Nac. Cordoba, t. 16, p. 402.

Fig. 108. Upper molar 1
of the left side—
natural size,
after Ameghino.

The species seems to have been founded on abundant material, representing an animal of larger size than P. holmbergi, which is distinguished by the greater width of the crowns of the incisors, by straight canines diverging but little, by a strong cingulum on the outer side of the lower molars and the inner side of the upper molars, and by the narrow symphysis of the lower jaws. P. superabile was distinguished by a difference in the arrangement of the roots of upper pm. 4, but as the pattern of the crown is the same, as is also the size, I feel that this difference is simply an individual variation. The following measurements are given by Ameghino:

Upper dentition,length from pm. 3 to m. 3240 mm.
Upper dentition,premolar 4, length30 mm.
Upper dentition,premolar 4, width43 mm.
Upper dentition,molar 2, length82 mm.
Upper dentition,molar 2, width83 mm.
Lower dentition,length from inc. 1 to m. 3  550 mm.