645 



BRADYPUS. 



BKADYPUS. 



C48 



crooked claws with which they are provided. The wrist and ankle 

 also are articulated or joined to the fore-arm and leg in an oblique 

 direction ; so that the palm or sole, instead of being directed down- 

 wards towards the surface of the ground, as in other animals, is 

 turned inwards towards the body, in such a manner as to render it 

 impossible for the Sloth to place the sole of its foot straight down 

 upon a level surface, but to compel it, under such circumstances, to 

 rest upon the external edge of the foot. This position is obviously 

 but ill adapted for ease or facility of motion. But there is still 



If placed upon a plain surface, the Sloth moves with difficulty and 



only by seizing upon the little asperities which he finds in his way, 



and by that means dragging his body slowly forwards, just as we may 



i observe a bat to do under similar circumstances. But this is a situa- 



j tion equally foreign to the habits and economy both of the Sloth and 



j of the bat ; and we are no more justified in judging of the nature of 



the one under these circumstances, than we should be in reasoning 



upon the habits of the other. The Sloth is eminently an arboreal 



quadruped : it is produced, it lives, and it dies in the trees ; it very 



Skeleton at the Sloth (D. tridactylus). 



another singularity in the structure of the foot of this animal which 

 materially increases its difficulties of progression on a plain surface. 

 This arises from the peculiar form of the last phalanx or joint of the 

 fingers and toes, that, namely, which gives insertion to the claws, 

 and which is articulated with the second phalanx in such a manner 

 as to permit the fingers and claws to be strongly bent inwards along 

 the palm and arm, but at the same time prevents the animal from 

 raising them upwards or opening the hand beyond a certain position. 

 This structure is exactly the reverse of what we observe in the com- 

 mon cat, which has the phalanxes of the toes formed in such a 

 manner as to keep the claws habitually retracted or drawn up, so 

 that it requires a considerable degree of muscular force to extend or 

 depress them. In the Sloths, on the contrary, they are naturally 

 depressed in the position represented in the figure of the skeleton, and 

 the muscular force is exerted to expand or open them. The claws 

 themselves are of a size altogether enormous, surpassing the entire 

 foot in length. They are so sharp and crooked that they readily 

 seize upon the smallest inequalities in the bark of the trees and 

 branches among which the animals habitually reside ; and, united to 

 the great muscular strength and rigid formation of the extremities, 

 furnish the most powerful weapons of defence. Nor are the form 

 and articulation of the posterior extremities less singular than those 

 of the anterior. The formation of the pelvis alone is of such a nature 

 as to render it im- 

 possible for the 

 Sloths to walk after 

 the manner of ordi- 

 nary quadrupeds ; 

 and 'the mode in 

 which the hind 

 legs are articulated 

 with the pelvis, to 

 use the expression 

 of Baron Cuvier, 

 seems almost ex- 

 pressly arranged for 

 the purpose of de- 

 priving the animal 

 of the use of its 

 legs altogether. 

 "If," says M. Cu- 

 vier, "we consider 

 the Sloths in the 

 relation which they 

 bear to other ani- 

 mals, the general 

 laws of organisation at present existing apply so little to their structure, 

 the different parts of their body seem so completely contradictory 

 of those laws of co-existence which we have found established in the 

 rest of the animal kingdom, that we might be almost tempted to 

 consider them as the remains of a former order of things, the living 

 relics of that precedent nature of which we are obliged to seek the other 

 ruins beneath the surface of the earth, and that they escaped by some 

 miracle the catastrophe which destroyed their contemporary species." 



rarely voluntarily descends to the surface of the earth, and those 

 therefore who observe it in that situation, have not a favourable 

 opportunity of judging of its nature and functions. 



We are indebted to the valuable observations of Mr. Waterton, 

 during his 'Wanderings' in South America, for a final and satis- 

 factory explanation of the apparent difficulties and inconsistencies 

 in the structure and habits of the Sloth. " The sloth," says this 

 traveller, " in ite wild state, spends its whole life in the trees, and 

 never leaves them but through force or accident ; and what is more 

 extraordinary, not upon the branches like the squirrel and monkey, 

 but under them. He moves suspended from the branch, he rests 

 suspended from the branch, and he sleeps suspended from the branch. 

 Hence his seemingly bungled composition is at once accounted for ; 

 arid in lieu of the sloth leading a painful life and entailing a melan- 

 choly existence upon its progeny, it is but fair to conclude that it 

 just enjoys life as much as any other animal, and that its extraordinary 

 formation and singular habits are but further proofs to engage us to 

 admire the wonderful works of Omnipotence." Nor are the motions 

 of this animal so slow while suspended in this strange position, nor 

 his habitat so circumscribed as naturalists have hitherto imagined. 

 " The Indians," continues Mr. Waterton, " have a saying that when 

 the wind blows the sloths begin to travel. In fact during calm 

 weather they remain tranquil, probably not liking to cling to, the 

 brittle extremities of the branches, lest they should break whilst the 

 animals are passing from one tree to another ; but as soon as the 

 wind rifles the branches of the neighbouring trees become interwoven, 

 and then the sloth seizes hold of them and pursues his journey in 

 safety. He travels at a good round pace, and were you to see him, ax 

 I have done, passing from tree to tree, you would never think of 

 calling him a sloth." Stedman, in his ' History of Surinam,' has an 

 engraving of a Sloth in this position, which we have copied, as illus- 



formation of the Pelvis. 



Mode of progression. 



trating its singular mode of progression. A specimen of Cltolcepvt 

 didactylut, the Two-Toed Sloth, is now living in the Gardens of the 

 Zoological Society, Regent's Park. 



The conformation of the extremities is not the only part of its 



