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Show 388 DARWINISM (' JIAI'. RECENT. ~- ~~ rI T ap~ Mi' Equus. 1:::,:~:::· ~ ~ f ~ (j; (B 9 7;:~~~;::;: ' i rr ~ {fJ 9 ~ ~ rw~~(H >re.oh;ppu•. i l f ~ 00 ~ ta .\IIOCE:\E. ~ Jlliohippus ~ (. ( nchitherinm). ::::.::~ '-~ f ~ D2 eB m FJG. S3.-Geological <.levclopmeul of the horse tribe (Eohtppus since dtseovereu} XI(! THE GEOLOGICAL EVIDENCES OF EVOLUTION 389 reason for the extinction has yet been given. Besides the characters I have mentioned, there are many others in the keleton, skull, teeth, and brain of the forty or more intermediate species, which show that the transition from the Eocene Eohippu. to the modern Equus has taken place in the order indicated" 1 ( ee Fig. 33). ''rel l may Professor Huxley say that this is demonstrative evidence of evolution ; the doctrine resting upon exactly as secure a foundation as did the Copernican theory of the motions of the heavenly bodies at the time of its promulgation. Both have the same basis-the coincidence of the observed facts with the theoretical requirements. Development of Dee1·'s II01·ns. Another clear and unmistakable proof of evolution is afforded by one of the highe t and latest developed tribes of mammals-the true deer. These differfrom all other ruminants in possessing solid deciduous horns which arc always more or less branched. They fir. t appear in the Middle Miocene formation, and continue down to our time; and their development has been carefully traced by Professor Boyd Dawkins, who thus . ummarises his results:- "In the middle stage of the Miocene the cervine antler consi ts merely of a simple forked crown (as in Corvus dicroceros), which increases in ize in the Upper Miocene, although it still remains small and erect, like that of the roe. In Cervus Matheroni it measures l 1·4 inches, and throws off not more than four tines, all small. The deer living in Auvergne in the succeeding or Pliocene age, present us with another stage in the hi tory of antler development. There, for the first time, we ee antlers of the Axis and Rusa type, larger and longer, and more branching than any antlers were before, and possessing three or more well-developed tines. Deer of this type abounded in Pliocene Europe. They belong to the Oriental division of the Cervidre, and their presence in Europe -confirms the evidence of the ·flora, brought forward by the Comte de Saporta, that the Pliocene climate was warm. They have probably disappeared from Europe in consequence 1 Lecture on the Introduction and 'uccession of Vertebrate Life in America, Natw-e, vol. xvi. p. 471. |