Article XXII. — A NEW GENUS OF GROUND SLOTH 

 FROM THE PLEISTOCENE OF NEBRASKA. 



By Barnum Brown. 



Plates L and LI. 



Paramylodon, gen. nov. 



This genus is founded on a nearly perfect skull and lower 

 jaw in the American Museum collections (No. 2780), with 

 associated skeletal material including five cervical vertebrae, 

 tibia, fibula, calcaneum, astragalus, lunar, middle digit of 

 manus, and ribs, found by the Expedition of 1897 near Hay 

 Spring, Nebraska. Professor Henry F. Osborn has placed 

 this material in the writer's hands for description. 



The following characters distinguish it from allied genera : 



Skull elongate ; muzzle inflated ; dentition | ; first upper molar the 

 largest of the series; last lower molar trilobate; first lower molar 

 without opposing tooth. 



Paramylodon seems to have been less specialized than 

 Mylodon, retaining features of the older, more primitive 

 sloths. From the long nasals it seems improbable that it 

 had a proboscis, while the greatly inflated muzzle, and the large 

 movable premaxillae, indicate a large prehensile lip. The re- 

 duction of the twelfth nerve ' shows a less specialized tongue 

 than in Mylodon. The rounded condyles, with the greater 

 part of the articular area on the ventral surface, and the 

 aspect of the foramen magnum, opening obliquely to the long 

 axis of the skull instead of backward, show that the head was 

 carried more at right angles to the vertebral column than in 

 Mylodon. The long calcaneum with posterior end resting 

 fiat on the ground, and the astragalar facet looking forward, 

 indicate a primitive foot more flexible at the ankle than in 

 the contemporaneous Mylodon. 



The sum of these characters points to a difference in feeding 

 habits and indicates that Paramylodon was a grazer. 



' As indicated by the small condylar foramen in the skull. 



