126 



THE DESEADO FORMATION OF PATAGONIA 



Coresodon Ameghino 



Coresodon Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 630. 

 Coresodon Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 459. 

 Coresodon Gaudry in part, 1908, Anal. Palaeontologie, t. I, p. 46. 



In this genus, the pattern of the upper molars is essen- 

 tially the same as in Proadinotherium, and they are of the 

 same hypsodont character, and with roots. I can now 

 find only the fact that in Coresodon the teeth are more 

 compressed and somewhat more hypsodont, as a feature 

 by which to distinguish this genus from Proadinotherium. 

 Gaudry figures the front of a lower jaw under the name 

 Coresodon which lacks the caniniform incisors. I have 

 doubted the association, but should it prove correct, then 

 this genus would be markedly different in that respect. 

 Two species have been described, C. scalpridens, and C. 

 cancellatus, both of which I consider the same. 



Coresodon scalpridens Ameghino 



C. scalpridens Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 630. 

 C. scalpridens Amegh., 1897, Bol. Inst., Geog. Argen., t. 18, p. 459. 

 C. cancellatus Amegh., 1901, Bol. Acad. Nac. Cienc. Cordoba, t. 16, p. 374. 



Of this species we found two specimens, one containing 

 the three lower molars, the other the second lower molar 



O o 



C 



D 



Fig. 82. Sections of second lower molar; A , top; B, 4 mm. down; C, 10 mm. down; 

 D, 1 8 mm. down natural size. 



only. In establishing C. cancellatus, Ameghino says it is 

 of the same size as C. scalpridens, but distinguished by the 

 basin in the upper molars being narrower, the internal 

 fold not being bifurcated, and by the absence of islets of 



