390 DARWINISM chap. 



of the lowering of the temperature in the Pleistocene age, 

 while their descendants have found a congenial home in the 

 warmer regions of Eastern Asia. 



" In the latest stage of the Pliocene — the Upper Pliocene of 

 the Val d'Arno — the Cer\T.is dicranios of Nesti presents us ^vith 

 antlers much smaller than those of the Irish elk, but very 

 complicated in their branching. This animal sur\'ived into 

 the succeeding age, and is found in the pre-giacial forest 

 bed of Xorfolk, being described by Dr. Falconer under the 

 name of Sedg^vick's deer. The Irish elk, moose, stag, reindeer, 

 and fallow deer appear in Europe in the Pleistocene age, all 

 ^yith highly complicated antlers in the adult, and the first 

 possessing the largest antlers yet kno^voi. Of these the Irish 

 elk disappeared in the Prehistoric age, after having lived in 

 countless herds in Ireland, while the rest have lived on into 

 our own times in Euro-Asia, and, Avith the exception of the 

 last, also in North America. 



" From this survey it is obvious that the cervine antlers 

 have increased in size and complexity from the JMid-Miocene 

 to the Pleistocene age, and that their successive changes are 

 analogous to those which are observed in the development of 

 antlers in the liAdng deer, which begin wdth a simple point, 

 and increase in number of tines till their limit of gTowth be 

 reached. In other words, the development of antlei's indicated 

 at successive and widely-separated pages of the geological 

 record is the same as that observed in the history of a single 

 living species. It is also obvious that the progressive 

 diminution of size and complexity in the antlers, from the 

 present time back into the early Tertiary age, shows that we 

 are approaching the zero of antler development in the Mid- 

 Miocene. No trace of any antler-bearing ruminant has been 

 met with in the lower Miocenes, either of Europe or the 

 United States." ^ 



Progressive Brain-Development. 



The three illustrations now given sufficiently prove that, 

 whenever the geological record approaches to completeness, 

 we have e^ddence of the progressive change of species in 

 definite directions, and from less developed to more de- 



^ Nature, vol. xxv. p. 84. 



