274 FAMILY TARDIGRADA ; SLOTHS. 



where the trees are less contiguous, they take advantage of windy 

 weather, which blows the boughs together, to effect their passage, 



FIG. 139. UNAU, OR TWO-TOED SLOTH. 



seldom coming to the ground, and completely stripping the tree 

 of its leaves and young shoots, rather than do so. From the 

 peculiar construction of the Sloth, and the remarkable power of 

 resisting tension, or strain, which its limbs seem to possess, it ap- 

 pears to feel no more fatigue from remaining suspended beneath a 

 branch for a long time together, than we do from sitting or stand- 

 ing erect, a position which the Sloth could not maintain for an 

 instant without support. The position which the Sloth assumes 

 during sleep, is no less peculiar than that of its period of activity. 

 It takes its place at the fork of a tree, the arms embracing the 

 trunk, the back resting upon the angle of the branch, and the 

 head reclining on the chest. The animal is thus rolled up almost 

 in the form of a ball ; the entire vertebral column, including the 

 neck, assumes a nearly circular curve ; and not only is the weight 

 of the whole body maintained in an attitude of ease and safety, but 

 the head is supported between the arms and chest, and the face 



