No. 2391. DESCRIPTIONS OF PLEISTOCENE VERTEBRATA—HAY. 639 



In general terms the description of the fourth metatarsal of Mylo- 

 don robustus applies to the corresponding one of Thinobadistes (Cat. 

 No. 2509d, pi. 119, fig. 9). However, the latter is narrower at its 

 distal end and gradually widens upward. It has a total length of 

 102 mm. ; the height of the distal end is 46 mm. The fifth metatarsal 

 (Cat. No. 2509e; pi. 119, fig. 9) has a length of 127 mm., very close to 

 that of Mylodon robustus. The greatest width of the proximal end is 

 56 mm. A comparison with Owen's figure will show that the distal 

 half of this bone is differently shaped in the two animals. In M. 

 robustus the outer border is nearly straight; in the Florida animal the 

 border is sigmoid. The distal end of the fifth metatarsal reaches 

 nearly to the distal end of the fourth; in M. robustus it falls consid- 

 erably short of reaching that point. The proximal end of the outer 

 border of this metatarsal is thick, and rounded; and it forms part of 

 a smooth surface which continues around to the underside of the 

 bone. This surface was probably covered by a pad of thickened skin 

 and bore much of the weight of the animal. 



The second phalanx in the collection appears to belong to the 

 median digit of the right hind foot (pi. 119, fig. 10). The total 

 length is 50 mm.; that taken along the axis of the bone 38 mm. The 

 height of the hinder end, taken in the median plane, is 33 mm.; the 

 width of this end, 35 mm.; the width of the distal articulation, about 

 25 mm. The base of an ungual phalanx (pi. 119, fig. 11) is taken to be 

 that of the hinder third digit, and it fits closely to the end of the sec- 

 ond phalanx just described. The height of the hinder end of the 

 bone is 45 mm.; the width, 38.5 mm. On the sides of the base of 

 the phalanx are indications of the presence of the sheath for the horny 

 claw; but, as represented in Owen's figure of the hinder median claw, 

 this sheath was deficient on the middle of the upper surface. 



It will be a matter of great interest to discover additional remains 

 of this animal, especially remains of the skull and teeth. In the 

 hinder foot the digits resemble much those of Mylodon; but the 

 astragalus, especially on the underside, is much like that of Mega- 

 therium. The size of the animal was about that of Mylodon robustus, 

 but considerably smaller than Mylodon sodalis from Christmas Lake. 



EXPLANATION OF PLATES. 



Plate 116. 



Figs. 1-7. Camelops huerfanensis. Upper teeth. X-7±: 



1. Right fourth premolar, grinding surface. 



2. Right first molar, outer face. 



3. Same tooth, grinding surface. 



4. Right second molar, outer face. 



5. Same tooth, grinding surface. 



6. Right third molar, outer face. 



7. Louver left hindermost molar. 



