MIOCENE PERIOD 159 



tailless branch of the family migrated in later times to South 

 America, and there attained considerable prosperity. 



Horses had increased in stature. Some as large as good- horses 

 sized Shetland ponies were now succeeding the harrier-sized 

 creatures of the last Period. The North American forms 

 probably were capable of much greater speed than their 

 predecessors, as their " extra " toes, though still in evidence, 

 were quite off the ground (Protohippus, Neohipparion). The 

 European forms do not seem to have attained the same com- 

 pactness of foot {Anchitherium) ; nor were their teeth so 

 strongly crowned as those of their American relations. 



At the same time there were horses in North America with 

 weU-developed and usable side-toes (Hyohippus). These 

 creatures probably frequented swampy regions, where weU- 

 splayed feet must have been of advantage. Their teeth, 

 moreover, were of an old-fashioned, weakly crowned type — 

 more fitted for marsh vegetation than for the hard grasses of 

 the plains. 



Pigs with their partiality for miry places were, like the swine 

 last-named horses, keeping their " extra " toes in a usable 

 condition. It is probable, however, that at this time the 

 main weight of the body was being thrown on the two inner 

 toes of the four. Some of these marsh-dweUers were becoming 

 more decided pigs as regards the shape of the skull (Lis- 

 triodon) ; but in some respects their dentition was rather that 

 of tapirs than of pigs ; and, at best, they were uncanonical 

 pigs. The most modern-hke forms on European scenes were 

 some diminutive creatures (Sus chceroides) that must have 

 closely resembled httle pigs that now haunt the forests of the 

 Andaman Islands. And as they embraced the essential 

 articles of pig anatomy, they may be spoken of as orthodox 

 pigs. 



Like rhinoceroses, pigs in North America never made much 

 progress ; and it was reserved for the old world to bring 

 porcine Ufe into importance. The highest forms in America 

 in Miocene times seem to have developed into peccaries ; and 

 swine of higher stamp than peccaries were not destined to 

 explore the forests of that continent. Big, two-toed pig- 

 like brutes, such as were in evidence in the last Period, were 



