THE ANTERIOR LIMBS OF QUADRUPEDS. 39 



pacted together, and armed with nails of great 

 size, which are concave below and pointed at 

 the tip ; in their ordinary position the palms 

 ai-e turned obliquely outwards, so that in the 

 act of scraping, the earth is tha-own on each 

 side of the animal. With these efficient in- 

 struments the bones and muscles of the arm 

 and chest are in complete accordance: the 

 bones of the arms are short, but very thick 

 and sohd, and the clavicles are almost in the 

 form of a solid square. The power concen- 

 trated in the anterior limbs of this animal is 

 indeed enormous, and in this respect it per- 

 haps excels every other burrower, even the 

 armadillo and the chlamyphorus. In such, 

 instruments we do not look for much sensi- 

 bility, or the power of manipulation ; the paws 

 are scrapers or shovels, and their use ibrbids 

 that they shovxld be more. 



From the burrowing mole let us turn to the 

 arboreal sloth — arboreal, but in a dissimilar 

 manner from the monkey. The sloth lives not 

 upon, but suspended under, the branches, and 

 travels along them in the dense forests of South 

 America, with the back downwards. It lives a 

 life of clinging ; and to this end its limbs are 

 structurally adapted. The arras are very long, 



