THE SLOTH 257 



fied, that is, changed into a true bony substance which 

 is everywhere externally invested by horny scales. 

 Almost always this external structure consists of a 

 solid shield on the head, one over the shoulders, and one 

 over the hinder portion of the body ; the back and sides 

 between the shoulders and hinder plates being in- 

 vested by transverse solid bands (the number of which 

 varies with the species), which are connected with each 

 other by soft, flexible skin, so as to allow the body to be 

 bent, and indeed, sometimes to be rolled up into a ball, 

 the soft ventral surface of the body being by this means 

 concealed, and the .hard solid coat presented against 

 attack on every side. 



Armadillos are small or moderate-sized animals, which 

 are mostly nocturnal, and feed on both animal and vege- 

 table substances; eating insects, worms, reptiles, roots, 

 and carrion. They are powerful and rapid burrowers, 

 by which faculty alone they can escape their enemies, for 

 they are not only harmless but defenceless save as 

 regards their armour and offer no resistance when 

 caught. As to them, Darwin tells us in his journal 

 during the voyage of the Beagle ; 



" In the course of a day's ride near Bahia Blanca, 

 several armadillos were generally met with. The instant 

 one was perceived, it was necessary, in order to catch it, 

 almost to tumble off one's horse : for in soft soil the animal 

 burrowed so quickly, that its hind quarters would almost 

 disappear before one could alight. It seems almost a 

 pity to kill such nice little animals, for, as a Gaucho said, 

 while sharpening his knife on the back of one, ' Son tan 

 maiisos ' (they are so quiet)." 



Most of the species, however, are prized as food. 

 In order to burrow, it is necessary that they should 

 move their fore limbs rapidly, and with much force. It 



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