64 THE DESEADO FORMATION OF PATAGONIA 



Prosotherium, ~~, upper inc. 2 and 3 and lower inc. 

 3 vestigal, upper pms. not molariform, molars with a deep 

 internal fold. 



Propachyrucos, 3 t 4 3 > lower jaw only, similar to Pa- 

 chyrukhos but have inc. 3, the canine, and pm. 1 present 

 and only a little reduced. 



P hemophilus, upper molars only, but peculiar in having 

 a strong external medial column. 



Prohegetotherium Ameghino 



Prohegetotherium Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 424. 



This little known genus is characterized by the upper 

 molars having an external furrow near the anterior margin 

 of the tooth. Otherwise it is similar to llegetotherium. 

 Ameghino described a species where the external surface 

 of the bones was sculptured "like reptiles." I do not see 

 how, with the arrangement of the muscles usual to mam- 

 mals, the sculpture could be similar to that of reptiles, and 

 feel that this is due to conditions of weathering. We did 

 not find this species, but did find a form which resembled 

 it in general, but differed in being smaller and with the 

 external furrow less developed. 



Prohegetotherium sculptum Ameghino 



P. sculptum Amegh., 1897, Bol. Inst. Geog. Argen., t. 18, p. 424. 



This species is characterized by the deep external fur- 

 row on the upper molars. The measure given is 34 mm. 

 for the length of the three upper molars. 



Prohegetotherium shumwayi sp. nov. 



Founded on a portion of the right maxilla, carrying pm. 

 2 to 4 and m. I, found on the Chico del 



^^~*** Chubut, west of Puerto Visser, by Waldo 



Fig. 20. II. Shumwayi Shlimway. 



The teeth are simple, with but a shallow 

 external furrow near the anterior margin of the premolars 



