PALAEOTHENTES 221 



of the Dcseado species. Later, however, he changed this 

 for Palacpanothus. As I can see no generic differences 

 between the Deseado and Santa Cruz species, I shall follow 

 Sinclair in using the generic term Palaeothentes. 



Palaeothentes chubutensis Ameghino 



Epanorthuschubutcnsis Amegh., 1897, Bol. Inst. Geog. Argcn., t. 18, p. 500. 

 Palaepanorthus chubutensis Amegh., 1901, Anal. Soc. Cienc. Argcn., t. 51, p. 



77- 

 Palaepanorthus chubutensis Amegh., 1902, Bol. Acad. Nac. Cienc. Cordoba, 



t. 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 — 2 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, I903, 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 



