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 Yal d’Arno—the Cervus dicranios of Nesti presents us with 
antlers much smaller than those of the Irish elk, but very 
complicated in their branching. This animal survived into 
the succeeding age, and is found in the pre-glacial forest 
bed of Norfolk, being described by Dr. Falconer under the 
name of Sedgwick’s deer. The Irish elk, moose, stag, reindeer, 
and fallow deer appear in Europe in the Pleistocene age, all 
with highly complicated antlers in the adult, and the first 
possessing the largest antlers yet known. 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, with 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 Mid-Miocene 
to the Pleistocene age, and that their successive changes are 
analogous to those which are observed in the development of 
antlers in the living deer, which begin with a simple point, 
and increase in number of tines till their limit of growth be 
reached. In other words, the development of antlers 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.” 1 
Progressive Brain-Development. 
The three illustrations now given sufficiently prove that, 
whenever the geological record approaches to completeness, 
we have evidence of the progressive change of species in 
definite directions, and from less developed to more de- 
1 Nature, vol. xxv. p. 84. 
