ERA OF THE TERTIARY FORMATION. 



in abundance (including an extraordinary one, of huge bulk, 

 named the Sivaiherium), carnivores, rodents, and insectivores. 

 Here also were monkeys, of unusual bulk ; but the most won- 

 derful animal as yet discovered in this region was a tortoise, 

 not distinguishable in any point of structure from a land species 

 now living, but reaching the surprising length of eighteen feet. 

 The discoveries among the tertiaries of South America have 

 been of a not less interesting character, in as far as they 

 equally show an approach to the existing zoological characters 

 of that region. Dr. Lund, a Danish naturalist, presents us 

 with a monkey, indicating the features of the platyrrhine or 

 New World group ; and the edentate order, which is still most 

 peculiar to that region, is there preceded by examples of vast size. 

 In the megatherium, megalonyx, scelidotherium, and mylodon, 



FIG. 70. 



Skeleton of Mylodon. 



we have a family of sloths, of elephantine magnitude, which 

 lived by breaking down and eating trees. The toxodon sur- 

 prises us not less, being a proportionally huge member of the 

 rodent order, that order which now includes most of the 

 smallest quadrupeds. 1 



1 The tertiary mammalia are chiefly described from the beautiful work 

 of Professor Owen, A History of British Fossil Mammalia and Birds. 1845. 



