56 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 69 



Genus PERAMYS Lesson 

 The tiny opossums of this genus are characterized by short ears 

 and hmbs, and very short, apparently non-prehensile tails. 



PERAMYS MELANOPS Goldman 



Panama Peramys 



[Plate 21, figs. I, 10] 



Peramys melanops Goldman, Smiths. Misc. Coll., Vol. 60, No. 2, p. 2, Sep- 

 tember 20, 1912. Type from Cana, eastern Panama (altitude 2,000 feet). 



The short-tailed opossums of the genus Peramys are apparently 

 rare in Panama. The type and only known specimen of P. melanops 

 is a small but robust animal with a non-prehensile tail less than two 

 and one-half inches in length. The upperparts are plain and very 

 dark brown in general color, the dorsal stripes, or spots, present in 

 some South American species being absent. 



The type specimen was taken in a trap set among rocks in the 

 heavy forest on the bank of the Cana River. 



Order EDENTATA. Edentates 



Family BRADYPODIDAE. Three-toed Sloths 



The three-toed sloths are strictly arboreal animals with short, 

 rounded heads, rudimentary tails, and sharp, strongly curved, hook- 

 like claws with which they hang back downward from the branches 

 of trees. The fore limbs are provided with three instead of two 

 digits as in Choloepodidae. The pelage of the top of the head is 

 inclined forward and forms a frontal ruff. The anterior teeth in the 

 upper jaw are reduced in size until they are the smallest of the series 

 and only slightly functional. The anterior teeth in the lower jaw are 

 large with a prominent longitudinal median ridge. These teeth shear 

 mainly with the second pair, the largest of the series in the upper jaw. 



Genus BRADYPUS LINNAEUS. Three-toed Sloth 

 Perhaps the best recognition mark of the genus is the possession of 

 three digits on the fore foot, a character already mentioned in 

 remarks on the family. Two species are known to inhabit Panama. 



BRADYPUS GRISEUS GRISEUS (Gray) 



Gray Three-toed Sloth 



Arctopithecus griseus Gray, Ann. Mag. Nat. Hist., Ser. 4, Vol. 7, p. 302, 

 April, 1871. Type from Cordillera del Chucu, western Panama. 



The three-toed sloths of Middle America, as far south as the Canal 

 Zone, are assignable to two fairly well-marked forms : B. casta- 



