1891.] The Litopterna. 693 
inwards. They are much smaller than the true molars (Fig. 5). 
Five species are known. The A. magnum Owen, the largest 
mammal of the Eocene of South America, equals a rhinoceros in 

FIG. 5.—Astrapotherium — Owen ; last five superior molars; about one-third 
natural size. From Ameghin 
dimensions. Its canine teeth, well developed in each jaw, ren- 
dered it a formidable animal. 
All the species of the Astrapotheriide are from the Lower 
Eocene of Patagonia. | 
EXPLANATION OF PLATE XVII. 
Macrauchenia patachonica Owen; from Burmeister; much reduced. 
Fig. 1.—Skull from above. 
Fig. 2.—Skull from below. 
Fig. 3.—Superior dental series. 
Fic. 4.—Inferior dental series. 
