16 



U. 8. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



and scantily clothed with short stiff depressed hairs, which constitute a very small pencil at the 

 end. The fur is very long and full, measuring three lines on the back. 



The upper parts are of a rather dark olive brown, with a hoary tinge, caused by penultimate 

 bars of grayish on the hairs. The sides are paler, with a tinge of chestnut ; the under parts 

 are of a yellow brownish white. The feet and under surface of the tail are white, with a dusky 

 yellowish tinge. 



The skull is moderately slender anteriorly. The dentition is -| + H + S = 32 - The 

 upper anterior incisor has a second hook at the base, decidedly smaller, however, than the one 

 in front of it forming the tip of the tooth and about equal to the third lateral tooth. The 

 first two lateral teeth are of equal size, and decidedly larger than the fourth, which, however, 

 is larger than the third. The teeth are all chestnut colored at the tips. 



Measurements of 630 (first four taken "before skinning). 



Several specimens in alcohol agree essentially with the preceding description taken from a 

 dried skin. In one or two the color of the back is a brighter chestnut than as described. 

 There is considerable difference in the thickness of the tails at the base, and the swelling of the 

 head ; these, however, are probably sexual characters, as they are most marked in the males. 

 In most specimens, the terminal pencil of hairs of the tail is worn off to a stump, or else want 

 ing, leaving the tip of the tail naked. In 1259 this pencil is, however, visible. 



Measurements from alcoholic specimens. 



