﻿210 
  E. 
  W. 
  Berry 
  — 
  Evolution 
  of 
  Plants 
  and 
  Animals. 
  

  

  anything 
  that 
  occurred 
  during 
  the 
  long 
  ages 
  of 
  the 
  

   Mesozoic. 
  

  

  That 
  the 
  evolution 
  of 
  the 
  higher 
  plants 
  was 
  one 
  of 
  the 
  

   important 
  factors 
  in 
  this 
  comparatively 
  sudden 
  efflores- 
  

   cence 
  of 
  the 
  mammal 
  and 
  bird 
  stocks 
  cannot 
  be 
  doubted. 
  

   The 
  small 
  Prototheria 
  of 
  the 
  Trias 
  sic 
  did 
  not 
  change 
  

   greatly 
  during 
  the 
  lapse 
  of 
  ages 
  because 
  the 
  food 
  supply 
  

   did 
  not 
  change 
  greatly 
  and 
  because 
  of 
  the 
  competition 
  

   for 
  it 
  of 
  the 
  reigning 
  race 
  of 
  reptiles, 
  and 
  it 
  may 
  be 
  sug- 
  

   gested 
  that 
  the 
  changing 
  food 
  supply 
  due 
  to 
  the 
  evolution 
  

   of 
  the 
  flowering 
  plants 
  and 
  which 
  is 
  suggested 
  as 
  one 
  of 
  

   the 
  important 
  factors 
  in 
  the 
  evolution 
  of 
  the 
  higher 
  mam- 
  

   mals, 
  was 
  also 
  one 
  of 
  the 
  factors 
  that 
  spelled 
  the 
  doom 
  

   of 
  the 
  overgrown 
  and 
  specialized 
  Reptilia 
  of 
  the 
  Meso- 
  

   zoic. 
  

  

  The 
  earliest 
  mammals 
  appear 
  to 
  have 
  been 
  insectivor- 
  

   ous. 
  The 
  various 
  orders 
  of 
  insects 
  are 
  old 
  geologically 
  

   and 
  that 
  they 
  existed 
  comfortably 
  before 
  the 
  higher 
  

   plants 
  were 
  evolved 
  is 
  obvious, 
  but 
  that 
  the 
  latter 
  became 
  

   an 
  attractive 
  source 
  of 
  food 
  and 
  were 
  the 
  stimulus 
  for 
  

   very 
  many 
  new 
  genera 
  and 
  species 
  cannot 
  be 
  doubted. 
  

   Thus 
  indirectly 
  the 
  flowering 
  plants 
  greatly 
  increased 
  

   the 
  food 
  supply 
  of 
  the 
  insectivorous 
  mammals. 
  The 
  

   Eodentia, 
  Edentata 
  and 
  Primates 
  depend 
  almost 
  entirely 
  

   upon 
  the 
  flowering 
  plants 
  for 
  food, 
  as 
  do 
  the 
  Ungulata, 
  

   and 
  indirectly 
  the 
  Carnivora, 
  since 
  the 
  latter 
  group 
  is 
  

   chiefly 
  dependent 
  on 
  the 
  aforementioned 
  groups 
  and 
  to 
  a 
  

   less 
  extent 
  upon 
  birds 
  or 
  cold 
  blooded 
  prey. 
  

  

  Upper 
  Cretaceous 
  floras 
  furnish 
  a 
  large 
  number 
  of 
  

   types 
  of 
  great 
  food 
  value, 
  and 
  among 
  fruits 
  — 
  palm 
  nuts, 
  

   figs, 
  walnuts, 
  persimmons, 
  etc. 
  Very 
  many 
  fleshy 
  fruits 
  

   are 
  found 
  in 
  the 
  Eocene 
  floras 
  and 
  these 
  even 
  include 
  

   among 
  their 
  number 
  such 
  specialized 
  fruits 
  as 
  dates 
  and 
  

   zapodillas 
  (Eoachras). 
  The 
  Ptilodus 
  skull 
  described 
  by 
  

   Gidley 
  (1909) 
  from 
  the 
  Fort 
  Union 
  Eocene 
  of 
  Montana 
  

   not 
  only 
  proved 
  the 
  marsupial 
  character 
  of 
  that 
  genus, 
  

   but 
  showed 
  considerable 
  dental 
  specialization 
  which 
  its 
  

   describer 
  attributed 
  to 
  frugivorous 
  habits. 
  

  

  The 
  relatively 
  sudden 
  differentiation 
  of 
  flowering 
  

   plants 
  immediately 
  antecedent 
  to 
  the 
  equally 
  sudden 
  dif- 
  

   ferentiation 
  of 
  the 
  Eocene 
  Mammalia 
  was 
  not 
  fortuitous 
  

   but 
  the 
  two 
  series 
  of 
  events 
  are 
  to 
  be 
  correlated. 
  Both 
  

   were 
  largely 
  accomplished 
  during 
  a 
  time 
  when 
  the 
  sea 
  

   had 
  retreated 
  for 
  the 
  most 
  part 
  from 
  the 
  continents 
  and 
  

  

  