OLIGOCENE PERIOD 141 



{ChalicotheriidcB). These quaint quadrupeds moved about 

 with the weight of the body thrown on the outside edge of 

 the foot, the feet being bent and twisted as in the case of some 

 existing ant-eaters. They were not forerunners of sloths 

 and ant-eaters, nor, indeed, of any animals outside their own 

 pecuhar line. The family, however, possessed considerable 

 staminal qualities : for it did not leave the arena of life 

 until the early Pliocene. 



Ganodonts — notable in the Eocene for edentate pro- edentates 

 clivities— had quite died out. Certain small creatures 

 aUied to aard-varks and scaly ant-eaters were certainly 

 appearing in Ohgocene times (Palceorycteropus, Necromanis, 

 Leptomanis) : but how far ganodonts were responsible for 

 these cannot be determined. 



Among the survivors of strange herbivores of Eocene titano- 

 times, the rhinoceros-Uke titanotheres were the most remark- theres 

 able. The Oligocene forms were of much less benignant 

 aspect than their Eocene forerunners. The latter were for 

 the most part unarmed beasts ; a few species only having 

 horns in faint sign or promise. Of very different aspect were 

 these later forms. Not only were they of larger size ; but 

 they had become grim-visaged with paired horns (Brontops). 

 The horns, certainly, may not have been as serviceable as they 

 appeared. They were located in the region of the nose — not 

 a very strong foundation — and were placed, not one in front 

 of the other as with two-horned rhinoceroses, but trans- 

 versely. They cannot, therefore, have been equal to great 

 strains. 



Titanotheres, in spite of these structural achievements, 

 stiU retained no small power of adaptation ; and in the 

 course of the Period they received strong calls to justify their 

 existence. In response to these demands the skull under- 

 went several modifications, and the horns increased in 

 length. The teeth also joined in the family effort. After 

 this display of energy the animals met with some success. 

 But it was only for a short time ; for long before the close 

 of the Period they one and all disappeared. They never seem 

 to have enjoyed an extensive range, for hardly any remains 

 of them are found outside limited areas in North America. 



