i64 EVOLUTION IN THE PAST 



other rodents that were then in the world had reached their 

 condition of development quite independently of the hoofed 

 animals. But here were rival forms that had issued from 

 the ranks of the ungulates. In other words, creatures were 

 climbing into the rodent fold by another way. This intru- 

 sion, as after events proved, was not to be tolerated. 



No animals describable as elephants seem to have been 

 in the fauna. But brutes were here (Pyrotherium) some- 

 what of the type of the hippopotamus-bears that in other 

 parts of the world had long since passed away (Amblypoda). 

 Life in South America was thus developing in a somewhat 

 peculiar manner ; and a fairly tranquil environment ensured 

 it a large measure of prosperity. Apparently no true carni- 

 vores were here to disturb the somnolence of the sloths, and 

 the long feeding hours of the toxodonts and other quaint 

 herbivores. Boisterous scenes there doubtless were among 

 the " lightning-beasts " ; but these, after all, were occa- 

 sioned by a laudable affection for the fair sex. 



CARNIVORES Lovers of meat, however, were in the land (Prothylacinus, 

 SPARASSO- BorhycBfia). These long-tailed and somewhat wolf-hke 

 DONTS animals, in being dull-witted, were to that extent in harmony 

 with the prevailing tone. They possessed strong afifinities 

 with marsupials, and are classed as such by some good 

 authorities. Their powers for scenting prey were exception- 

 ally well developed ; and some of them seem to have been 

 adapted to arboreal habits (Cladosictis). Their teeth, it must 

 be admitted, were not of up-to-date type ; but the animals, 

 no doubt, fared sumptuously on the sleepy herbivores. Their 

 feasts — probably indulged in at night— led not infrequently 

 to squabbles among themselves, and there is evidence that 

 ugly wounds were inflicted in altercations. 

 MONKEYS The highest class of the population consisted of feeble- 

 minded, fiat-nosed monkeys of the " howler " type {Homun- 

 culus). The first comers had probably arrived by chance 

 from lands north of the existing isthmus, having been carried 

 across the dividing sea on drifting tree-trunks. Their advent 

 was, no doubt, much resented by the old quiet-loving resi- 

 dents. 



MARSUPIALS Undoubted marsupials seem to have been limited in 



