XIII 



PHYLUM CHORDATA 



469 



adapted, in the structure of their limbs, to an arboreal life than 

 any other group of the Mammalia. They have a short, rounded 

 head, with small pinnae, and long slender limbs, the anterior much 

 longer than the 

 posterior, with the 

 digits, which are 

 never more than 

 three in number, 

 long, curved, and 

 hook-like, adapted 

 for enabling the 

 animal to hang 

 and climb, body 

 downwards, among 

 the branches of 

 trees. In the 

 three-toed Sloth 

 there are three 

 toes in both maims 

 and pes ; in the 

 two - toed Sloth 

 there are only two 

 in the manus, 

 three in the pes. 

 The tail is rudi- 

 mentary. The 

 body is covered 

 with long, coarse 

 hairs, which differ 

 from those of other 

 Mammals in be- 



1 ^ J4*vxllW FlG - 1048. Unau. or Two-Toed Sloth (Cholcepus didactylm). 

 mg longitudinally '(After Vogt and Specht.) 



fluted. On these 



hairs grows abundantly an alga, the presence of which gives a 



greenish tinge to the fur. 



The ordinary Anteaters (Myrmecophaga) have a greatly elongated 

 snout, with the mouth as a small aperture at its extremity, small 

 eyes, and the auditory pinna sometimes small, sometimes well 

 developed. There are five digits in the fore-foot, of which the 

 third has always a very large, curved and pointed claw, render- 

 ing the manus an efficient digging organ. The toes of the hind- 

 foot, four or five in number, are sub-equal, and provided with 

 moderate-sized claws. In walking, the weight of the body rests 

 on the dorsal surfaces of the second, third and fourth digits of the 

 manus, and on a thick callous pad on the extremity of the fifth, 

 and, in the pes, on the entire plantar surface. The tail is always 

 very long, and is sometimes prehensile. The body is covered with 

 long hair. In the Two-toed Anteater (Cydoturus} the muzzle is 



