128 FOSSIL MAMMALIA. 



It remains to consider, of what use this cuirass could have 

 been to the gigantic animal on which it probably was placed. 

 As the locomotive organs of the Megatherium indicate very 

 slow power of progression, the weight of a cuirass would 

 have afforded little impediment to such tardy movements; 

 its use was probably defensive, not only against the tusks 

 and claws of beasts of prey, but also, against the myriads 

 of insects, that usually swarm in such climates as those 

 wherein its bones are found ; and to which an animal that 

 obtained its food by digging beneath a broiling sun, would 

 be in a peculiar degree exposed. We may also conjecture 

 it to have had a farther use in the protection afforded by it 

 to the back, and upper parts of the body ; not only against 

 the sun and rain, but against the accumulations of sand and 

 dust, that might otherwise have produced irritation and 

 disease.* 



Mr. Parish. Although no armour was found with the fragrnents of tlie 

 large skeleton, in tlic bed of tiic Salado, the rough broad flattened surface of 

 a part of the crest of the ileum of this skeleton, (see PI. 5, Fig. 2. r, s,) and 

 the broad condition of the summit of the spinous processes of many vcrlebrse, 

 and also of the superior convex portion of certain ribs on which the armour 

 would rest, afford evidence of pressure, similar to that we find on the ana- 

 logous parts of the skeleton of the Armadillo, from which we might have in- 

 terred that the Megatherium also was covered with heavy armour, even had 

 no sueh armour been discovered near bones of this animal in other parts of 

 the same level district of Paraguay. In all these flattened bones the effects 

 of pressure are confined to those parts of the skeleton, on which the armour 

 would rest, and are such as occur in a remarkable degree in the Armadillo. 



* To animals that dig only occasionally, like Badgers, Foxes, and Rab- 

 bits, to form a habitation beneath the ground, but seek their food upon the 

 surface, a defence of tins kind would not only have been unnecessary but 

 inconvenient. 



The Armadillo and Ciilamyphorus are the only known animals that 

 have a coat of armour compoFed of thick plates of bone, like that of the 

 Megatherium. As this peculiar covering is confined to these quadrupcdsi 

 we can hardly imagine its use to be solely for protection against other 

 Ijeasts and insects; but as the Armadillo obtains its food by digging in, 



