PARASTRAPOTHERIUM 



143 



Ameghino has described several genera, which make 

 a progressive series and show a constantly progressive 

 variation as far as they are known. 



Genus 



Albert ogaudryi 



Formation 

 Casamavor 



Formula 



Post, inner and post, 

 median, cusps isola- 

 ted. 



? 1 ? 3 



Astraponotus 



Astraponotus 



123 Post, inner cusp, uni- 

 ted with wall making 

 small lobe. 



Parastrapotherium Deseado and Colpodon 



Astrapothericulus Astrapothericulus 

 Astrapotherium Santa Cruz 



123 Post, lobe large, also 

 3123 



a strong crista. 



In the Deseado beds, beside Parastropotherium, Ame- 

 ghino has described Liarthrus, based on an upper second 

 premolar and part of another tooth, but I can see no 

 structural variation from Parastropotherium or indeed from 

 P. holmbergi; so I consider this genus as a synonym. As 

 to the genus Traspoatherium, I can not see in it any reason 

 for making a genus separate from Parastrapotherium. 



Parastrapotherium Ameghino 



Parastrapotherium Amegh., 1895, Bol. Inst. Ceog. Argen., t. 15, p. 636. 

 Parastrapotherium Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 449. 

 Liarthrus Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 641. 

 Liarthrus Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 451. 

 Traspoatherium Amegh., 1895, Bol. Inst. Geog. Argen., t. 15, p. 641. 

 Traspoatherium Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 450. 



The genus, in general, is similar to Astrapotherium, so 

 that Gaudry considered it the same, but Ameghino has 

 distinguished it by the tushes being relatively of smaller 

 size, the lower incisors larger, and by the presence of pm. 3 



