THE ANTERIOR LDlfiS OF QUADRUPEDS. 41 



intensely powerful arms of the sloth enjoy great 

 freedom of movement. The animal, while 

 resting, can stretch them out in every direc- 

 tion, in order to collect the tender buds and 

 leaves on Avhich it feeds, or draw down the 

 young twigs to its mouth. These arms, thus 

 provided with powerful claws, are formidable 

 instruments of defence. Serpents capable of 

 ascending trees, are among the sloth's most 

 dreaded enemies ; but these it can grapple and 

 crush, as with the power of a vice, by means 

 of its terrible claws. When attacked on the 

 ground, to which it very seldom voluntarily 

 descends, it throws itself on its back, strikes 

 vigorously with its paws, endeavouring to 

 grapple with its antagonist ; and has been 

 known to strangle a dog, holding him at arms' 

 length. The long continuance and the un- 

 yielding rigidity of the grasp of the sloth, are 

 very remarkable, betokening an almost spas • 

 modic contraction of the muscles, and are, 

 doubtless, connected with a peculiar plexiform 

 arrangement of the arteries of the limbs. On 

 one occasion, as related by Kircher, a long pole 

 Avas put under the feet of one of these animals, 

 which it seized very firmly, and would not let 

 go again. The animal thus voluntarily sus- 



B 3 



