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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1927 
  

  

  able 
  to 
  expand 
  with 
  the 
  increasing 
  territory 
  suitable 
  for 
  its 
  living 
  

   conditions, 
  the 
  struggle 
  becoming 
  less 
  severe 
  between 
  individuals 
  

   and 
  species 
  and 
  more 
  a 
  struggle 
  between 
  the 
  living 
  creatures 
  and 
  

   their 
  environment, 
  resembling 
  in 
  this 
  respect 
  the 
  struggle 
  of 
  the 
  

   early 
  pioneers 
  with 
  the 
  new 
  American 
  environment. 
  A 
  notable 
  

   example 
  of 
  the 
  expansional 
  evolution 
  of 
  marine 
  life 
  under 
  a 
  situation 
  

   such 
  as 
  that 
  just 
  mentioned 
  is 
  shown 
  in 
  the 
  crinoidal 
  faunas 
  of 
  early 
  

   Mississippian 
  age 
  in 
  the 
  interior 
  of 
  North 
  America. 
  The 
  rapid 
  

   evolution 
  of 
  these 
  organisms 
  at 
  this 
  time 
  led 
  to 
  their 
  dej)loyment 
  

   into 
  a 
  greater 
  number 
  of 
  genera 
  and 
  species 
  than 
  are 
  known 
  else- 
  

   where 
  in 
  the 
  paleontological 
  record. 
  From 
  the 
  interior 
  province 
  of 
  

   North 
  America 
  as 
  the 
  original 
  home 
  of 
  this 
  fauna, 
  it 
  spread 
  outward 
  

   into 
  distant 
  parts 
  of 
  the 
  world, 
  the 
  generic 
  and 
  specific 
  representation 
  

   becoming 
  more 
  and 
  more 
  attenuated 
  as 
  distances 
  were 
  increased. 
  

  

  Examples 
  of 
  the 
  migratory 
  wanderings 
  of 
  the 
  now 
  extinct 
  faunas 
  

   of 
  the 
  past 
  could 
  be 
  multiplied 
  almost 
  indefinitely, 
  but 
  in 
  no 
  case 
  is 
  

   there 
  a 
  record 
  of 
  a 
  truly 
  world-wide, 
  cosmopolitan 
  fauna, 
  either 
  of 
  

   the 
  land 
  or 
  of 
  the 
  sea. 
  What 
  has 
  hindered 
  such 
  a 
  development 
  has 
  

   been 
  the 
  dependence 
  of 
  these 
  living 
  groups 
  of 
  organisms 
  on 
  their 
  

   environmental 
  conditions. 
  Had 
  a 
  time 
  ever 
  existed 
  in 
  the 
  past 
  when 
  

   the 
  conditions 
  of 
  temperature, 
  purity 
  of 
  water, 
  salinity, 
  and 
  other 
  

   environmental 
  factors 
  had 
  been 
  uniform 
  throughout 
  the 
  whole 
  of 
  the 
  

   shallow 
  marine 
  waters 
  of 
  the 
  earth, 
  and 
  at 
  the 
  same 
  time 
  had 
  there 
  

   been 
  free 
  means 
  of 
  communication 
  between 
  all 
  of 
  the 
  shallow 
  waters, 
  

   no 
  paleontologist 
  can 
  doubt 
  that 
  a 
  uniform, 
  world-wide, 
  shallow- 
  

   water 
  marine 
  fauna 
  would 
  have 
  sprung 
  into 
  existence. 
  The 
  two 
  fac- 
  

   tors 
  controlling 
  such 
  a 
  development 
  are 
  environment 
  and 
  the 
  paths 
  

   of 
  communication. 
  Perhaps 
  a 
  lesser 
  degree 
  of 
  uniformity 
  among 
  

   the 
  land-living 
  creatures 
  of 
  the 
  past 
  has 
  obtained 
  than 
  among 
  those 
  

   of 
  the 
  marine 
  waters, 
  for 
  the 
  reason 
  that 
  differences 
  in 
  environment 
  

   are 
  perhaps 
  generally 
  more 
  sharply 
  limited 
  on 
  land 
  than 
  in 
  the 
  

   shalloAv 
  marine 
  waters. 
  The 
  earthly 
  habitat 
  where 
  the 
  most 
  uniform 
  

   environment 
  exists 
  to-day 
  is 
  found 
  in 
  the 
  abysmal 
  depths 
  of 
  the 
  

   ocean, 
  and 
  the 
  life 
  of 
  these 
  cold 
  and 
  dark 
  abysses 
  is 
  essentially 
  the 
  

   same 
  in 
  all 
  oceans. 
  

  

  In 
  the 
  application 
  of 
  these 
  factors 
  of 
  environment 
  and 
  communica- 
  

   tion 
  to 
  man's 
  distribution 
  and 
  social 
  organization 
  throughout 
  the 
  

   world 
  may 
  we 
  not 
  look 
  forward 
  to 
  results 
  similar 
  to 
  those 
  exhibited 
  

   among 
  the 
  more 
  lowly 
  creatures 
  whose 
  recorded 
  history 
  carries 
  us 
  

   back 
  for 
  some 
  hundreds 
  of 
  millions 
  of 
  years. 
  In 
  so 
  doing 
  the 
  factor 
  

   of 
  environmental 
  control 
  may 
  be 
  largely 
  or 
  wholly 
  disregarded, 
  

   because 
  man 
  has 
  been 
  able 
  to 
  adapt 
  himself 
  to 
  all 
  sorts 
  of 
  terrestrial 
  

   environment. 
  Upon 
  these 
  conditions 
  the 
  factor 
  of 
  communication 
  

   becomes 
  dominant. 
  

  

  