PRONESODON 125 



MEASUREMENTS 



Skull, width across the zygomatic arches 148 mm. 



Skull, width across opposite m. 3 (outside) 73 mm. 



Upper dentition, molar 2, length 25 mm., width 13 mm. 



Upper dentition, molar 3, length 23 mm., width 12 mm. 



Lower dentition, incisor 3, length 13 mm., width 7 mm. 



Lower dentition, molar 2, length 20 mm., width 7^ mm. 



Proadinotherium angustidens Ameghino 



P. angustidens Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 467. 



This is based on a single lower tooth, which is considered 

 either pm. 4 or m. I, and measures 13 mm. long by 4^ mm. 

 wide. 



Pronesodon Ameghino 



Pronesodon Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 626. 



The genus is said to resemble Proadinotherium, but with 

 the caniniform incisors proportionally much shorter. An 

 associated calcaneum is shorter than that of Adinotherium 

 and longer than that of Nesodon. 



Two species are described. 



Pronesodon cristatus Ameghino 



P. cristatus Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 626. 

 P. cristatus Amegh., 1897, Bol. Inst. Geog. Argen., t. 15, p. 467. 



This species is very imperfectly known, is characterized 

 by a large external anterior style, molars said to be 15 mm. 

 wide. 



Pronesodon robustum Ameghino 



P. robustum Amegh., loc. cit. above. 



This is a larger species, of which the three lower molars 

 are known, and which measure 16, 22, and 30 mm. in length 

 respectively, while they are 9-10 mm. wide. 



