EDENTATA. 567 



sion oniy when absolutely compelled to do so. Whilst the 

 name of " Sloth " may thus appear to be a merited one from 

 the point of view of a terrestrial Mammal, it is wholly unde- 

 served when the animal is looked upon as especially adapted 

 for an arboreal existence. In the Ai or Three-toed Sloth 

 (Brady pus tridactylus] there are three toes to each foot, and 

 these are short, completely rigid, and so enveloped in the in- 

 tegument as to leave nothing visible except the enormously 

 long and crooked claws. The hand and foot are jointed to 

 the arm and leg obliquely, so that the palm and sole cannot be 

 applied to the ground, but are turned inwards. The ungual 

 phalanges are also so articulated that the claws are bent inwards 

 towards the palm or sole. There are sixteen pairs of ribs. 

 The molars are rootless, growing from permanent pulps, and 

 consisting of a simple cylinder of dentine enveloped in enamel. 

 In the Unau (Cholczpus] the feet are two-toed, and there are 

 twenty-three pairs of ribs, the greatest number known in the 

 Mammals. 



The second family of the Edentata is that of the Dasypodidce, 

 or Armadillos. These are found exclusively in South America, 

 as are the Sloths, but they are very different in their habits. 

 The Armadillos are burrowing animals, furnished with strong 

 digging-claws and well-developed collar-bones. The jaws are 

 provided with numerous simple molars, which attain the enor- 

 mous number of nearly one hundred in the great Armadillo 

 (Dasypus gigas}. The upper surface of the body is covered 

 with a coat of mail, formed of hard bony plates or shields, 

 united at their edges. A portion of this armour covers the 

 head and shoulders, and another portion protects the hind- 

 quarters ; whilst between these is generally a variable number 

 of movable bands which run transversely across the body and 

 give the necessary flexibility to this singular dermoskeleton. 

 In some species this flexibility is so great that the animal can 

 roll itself up like a hedgehog. The tail is likewise mostly 

 covered with bony scutes. 



The Armadillos are confined entirely to South America, 

 ranging from Mexico to Patagonia. In this country, also, have 

 been found the remains of a gigantic armour-plated animal 

 allied to the Armadillos, which will be subsequently described 

 under the name of the Glyptodon. Amongst the best known 

 species of Armadillo are the Peba (Dasypus Peba), the Poyou 

 (D. sexdnctus), the Tatouay (D. Tatouay], and the Great Arma- 

 dillo (D. gigas). A somewhat aberrant form is the Chlamyphorus 

 (fig. 242) of South America, the total length of which is only 

 about six inches. 



