92 Professor Owen on the Megatherium. 
common to the Edentate order; but in the expanse and massive 
ness of the iliac bones, it can only be compared with other eX- 
tinct members of its own peculiar family of Phyllophagous Eden- 
tata. Its habits necessitating a strong and powerful tail, we find 
this resembling, in its bony structure, that of other Edentata with 
a similar appendage, especially in the independency of the tw 
hemapophyses of the first caudal, a character which obtains in 
the great ant-eater and in some armadillos ; but this is no evr 
dence of direct affinity to either of these families ; the habits of 
the small arboreal sloths render their eminently prehensile limbs 
sufficient for their required movements, and the tail is wanting: 
Had that appendage been proportionally as large as in the Meg® 
therium, we cannot suppose that the caudal vertebrae would have 
‘materially differed from those of other Edentata. 
In the coalescence of the anterior vertebral ribs with the bony 
sternal ribs, the Megatherium resembles the sloths. This esse” 
digit (pollex) which? is retained in the ant-eaters and armadillos 
*is obsolete in the Megatherium, as in the sloths and Orycteropus: 
‘three digits are fully developed and armed with claws, as in the 
Bradypus tridactylus ; and the fifth, though incomplete in He 
- Megatherium, is better developed, because it was required in 
ponderous terrestrial sloth, for its progression 0 
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nt Sagreneata ceatomans 
n level ground. 10 | 
