326 LLOYDS NATURAL HISTORY. 



tually on the ancestral line in question. Its upper molar teeth 

 are not very unlike those of the Palzeotheres, but have the 

 oblique cross-crests narrower, less inclined, and separated by a 

 more open valley. Although very common in the Middle and 

 Lower Eocene beds of the Continent, the large genus of Odd- 

 toed Ungulates known as Lophiodoii are represented in Britain 

 only by a single species from the Bracklesham beds. While 

 their teeth are of the same general type as those of the Palae- 

 otheres and Anchilophus^ the upper molars differ in having the 

 outer wall formed by sub-conical columns instead of flattened 

 lobes, thereby resembling the corresponding teeth of the modern 

 Tapirs. Although most, if not all of these Lophiodons died out 

 without giving origin to any posterity, the case is very different 

 with the nearly allied little Hyracotherium^ originally described 

 upon the evidence of an imperfect skull from the London clay 

 at Heme Bay, since this genus is one of the earliest to which 

 the ancestry of the Horse can be traced. Thanks to the per- 

 fect preservation of specimens discovered in the United States, 

 where they were long known under a totally different name, we 

 now know that the Hyracothere was a small four-toed animal, 

 intimately connected with a still earlier five-toed type, while 

 superiorly it leads on to the Aiichilophus and certain allied 

 Miocene continental forms, and thus to the modern Horse. 

 The Hyracothere received its name from an idea that it was re- 

 lated to the existing Hyrax; and it is a curious commeiit on the 

 early history of palaeontology to notice that the lower teeth of 

 a second species obtained from the Lower Eocene sand of 

 Kyson, in Suffolk, were at first supposed to pertain to a 

 Monkey. 



If the palceontological riches of the United States have 

 helped in the elucidation of the true affinities of the Hyraco- 

 there, still more markedly is this the case with regard to the 

 much larger Ungulate originally described 011 the evidence of 



