PLEUROCOELODON 



131 



T. biconus Amegh., 1897, Bol. Inst. Geog. Argen., t. 18. p. 

 484. 



This species is based on two lower premolars, said to be 

 the same size as T. angustus, but with the pillar larger. 



Pleurocoelodon Ameghino 



Pleurocoelodon, Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 645. 

 Pleurocoelodon, Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 484. 



This genus is distinguished by the absence of the style 

 on the anterior external margin of the upper molars, in- 



Fig. 89. P. wingei — natural size; A, first molar; 

 B, third molar. 



stead of which the external face is excavated medianly. 

 Two species are described, based on isolated upper teeth. 



P. wingei Ameghino 



P. wingei Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 645. 

 P. wingei Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 485. 



This species is founded on a couple of isolated molars, 

 probably belonging to the same individual. The following 

 measurements are given: 



Upper molar I, length 

 Upper molar 3, length 



22 mm., width 26 mm. 

 24 mm., width 29 mm. 



P. cingulatus Amegh., loc. cit. above, is based on an in- 

 complete upper molar, probably the second, which is dis- 

 tinguished by having the internal cingulum excessively 

 developed. It measures 30 mm. in length. 



