

SLOTHS, ANT-EATERS AND ARMADILLOS. 183 



By the natives of the tropical forest-regions of South and Central America, 

 where sloths are alone found, the three-toed kinds are spoken of as ai', while 

 the name of unau is applied to the mem- 

 bers of the two-toed group. Mainly 

 nocturnal in their habits, sloths appear 

 to be sluggish creatures, passing the 

 daylight hours curled up with the head 

 safely tucked between the fore-limbs, 

 and at night wandering about slowly 

 in search of food, which consists solely 

 of leaves and other vegetable sub- 

 stances. Caution is a great character- 

 istic of their movements, a fresh branch 

 being firmly seized before hold is 

 relaxed of the one they are about to Fig. 97 THREE-TOED SLOTH 



leave. They are usually found either (Dradypus tridactylus). 



singly or in small family parties ; and 



the females produce but. a single offspring at a birth, which is fully 

 developed, except in the matter of size, when it makes its appearance in the 

 world. 



The second family of the edentates is formed by the South American or 

 true ant-eaters (Myrmecophagidce), of which there are three species, referable 

 to as many genera ; one of these being strictly terrestrial, 

 while the other two are more or less arboreal in their habits. Ant-Eaters, 

 So unlike are these creatures, both as regards external 

 character and the structure of their skeleton, to the sloths, that it is at first 

 sight difficult to believe that there is any very intimate relationship between 

 the two groups. And, indeed, were it not that in the superficial deposits of 

 South America there occur remains of certain extinct edentates known as 

 ground-sloths (of which the gigantic Megalotherium is a familiar example in 

 our museums), forming to a great extent a group intermediate between the 

 sloths and the ant-eaters, it would be difficult even for zoologists to fully 

 realise how intimate this relationship really is. Taking the existence of 

 these extinct connecting links for granted, it may be noticed that in place of 

 the short and rounded head of the sloths, the ant-eaters have the head and 

 skull more or less elongated and narrow, while the slender jaws are entirely 

 toothless, and the tongue is long, cylindrical, and capable of being protruded 

 far in advance of the lips. The degree of elongation of the skull is, however, 

 by no means the same in all the members of the group, the maximum 

 development in this respect being exhibited in the case of the great ant- 

 eater. Still more striking is the difference in the structure of the feet in the 

 two groups. In the great ant-eater, for instance, the fore-foot is furnished 

 with five complete toes, the middle one of which is much larger and more 

 powerful than the rest ; and all but the fifth, or outermost, are furnished 

 with strong claws. In this genus there are also five toes to the hind-feet ; 

 but in the third representative of the family there are only four claws to each 

 foot. When the great ant-eater is walking, only the extreme outer side and 

 part of the upper surface of the fore-foot is applied to the ground ; but 

 in the hind-foot, which has the fourth toe the largest, and claws to all 

 five, the whole of the short and wide sole touches the ground in 

 the ordinary manner. An important point of distinction from the sloths 

 is that the bones of the terminal joints of the fore-feet have a longi- 



