One of the plates we found has the rough surface, obscure figure, two pits on the median part of the surface, and marginal piliferous pits, of which the first two features are characters of P. undulatus, the last is the feature of P. depressus, so I have combined the two species. A second plate does not have the marginal pits but is otherwise the same. I expect considerable variation in the pattern on plates from different regions of the carapace.

Peltephilus protervus Ameghino

P. protervus, Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 509.

This species, of which we found no representative, is very large. The plates of the type have two pits on the anterior part of the exposed surface and none on the margin. A movable plate measures 41 mm. long by 22 mm. wide. One of the horn-like plates from the cephalic shield is 35 mm. long, by 30 mm. wide, and has a height of 44 mm.

GLYPTODONTIA

This suborder is most sparingly represented, apparently on account of unfavorable habitat. Ameghino has described a few fragments of the carapaces of these forms, making the genera, Palaeopeltis, and Glyptatelus, both pre-Santa Cruz genera.

Palaeopeltis Ameghino

Palaeopeltis Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 659.

The basis of this genus is a few plates of a glyptodon-like animal of considerable size, but the plates are without ornamentation. This form Ameghino considers intermediate between glyptodonts and armadilloes. I feel that there is too little of the skeleton known to justify this conclusion, especially as glyptodonts of a considerably higher grade of specialization are contemporaries of this form.