PALAEOTHENTES 220 
of the Deseado species. Later, however, he changed this 
for Palaepanothus. As 1 can see no generic differences 
between the Deseado and Santa Cruz species, I shall follow 
Sinclair in using the generic term Palacothentes. 
Palaeothentes chubutensis Ameghino 
Epanorthus chubutensis Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 500. 
Palaepanorthus chubutensis Amegh., 1901, Anal. Soc. Cienc. Argen., t. 51, p. 
77: 
Palaepanorthus chubutensis Amegh., 1902, Bol. Acad. Nac. Cienc. Cordoba, 
i) 18, p: 123. 
Palaepanorthus chubutensis Amegh., 1903, Anal. Mus. Nac. B. A., t. 9 (ser. 
3, t. 2) p. 239. 
The species is founded on a tiny mandible with premolar 
3-molar 3, on which the third premolar, while reduced, 
Fig. 145. Right mandible—z2 times natural size, after Ameghino. 
has two roots and reaches the height of the fourth premolar, 
being in about the same stage of development as the Santa 
Cruz species. As we found no specimens of this species I 
reproduce Ameghino’s figure and measurements. 
Lower dentition, premolar 3 to molar 3 19 mm. 
Lower dentition, height under premolar 4 12 mm. 
Pilchenia Ameghino 
Pilchenia Ameghino, 1903, Anal. Mus. Nac. Buenos Aires, ser. 3, t. 2, p. 128. 
Pilchenia Ameghino, 1904, Anal. Soc. Cienc. Rep. Argen., t. 58, p. 259. 
This genus was founded on a single lower molar which, 
in the light of the specimen we found, I take to be the third 
