30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8l 



cavity on the posterior face of the shaft at the base of the great 

 trochanter. 



Unfortunately no perfect skulls of ground sloths have yet been 

 found in the Haitian caves. One specimen from the small cave near 

 St. Michel includes the interorbital region and anterior part of the 

 braincase. It is about the size of the corresponding part of the skull 

 in a large Acratocnus odontrigonus, but is conspicuously different 

 in form, owing to the absence of the deep postorbital constriction 

 which is such a noticeable feature in the skull of Acratocnus. Whether 

 this fragment pertains to a skull of Parocnus or of Acratocnus ( ?) 

 conies is a question which cannot be answered. A fragment of a 

 palate from the same cave appears to have come from a skull of 

 much the same size. It indicates a palate twice as wide in proportion 

 to the length of the toothrow as that of Acratocnus odontrigonus, 

 and it further differs from the palate of the Porto Rican sloth in 

 the presence of a median longitudinal ridge supplemented, on each 

 side, by a shallow but well-defined longitudinal furrow. The toothrow 

 in this individual was probably of almost exactly the same length 

 as that of the Porto Rican specimen figured by Anthony on plate 69 

 (fig. ic). 



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