﻿786 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [28] 
  

  

  water, 
  they 
  may 
  be 
  regarded 
  as 
  having 
  slowly 
  spread 
  themselves 
  over 
  

   the 
  floor 
  of 
  the 
  ocean, 
  but 
  without 
  undergoing 
  great 
  modifications, 
  owing 
  

   to 
  the 
  extreme 
  uniformity 
  of 
  the 
  conditions 
  and 
  the 
  absence 
  of 
  competi- 
  

   tion.. 
  Or 
  we 
  may 
  suppose 
  that 
  in 
  the 
  depressions 
  which 
  have 
  taken 
  

   place 
  near 
  coasts 
  some 
  species 
  have 
  been 
  gradually 
  carried 
  down 
  to 
  

   deep 
  water, 
  have 
  accommodated 
  themselves 
  to 
  the 
  new 
  conditions, 
  and 
  

   have 
  gradually 
  migrated 
  to 
  the 
  regions 
  far 
  from 
  land. 
  A 
  few 
  species 
  

   may 
  thus 
  have 
  migrated 
  to 
  the 
  deep 
  sea 
  during 
  each 
  geological 
  period. 
  

   In 
  this 
  way 
  the 
  origin 
  and 
  distribution 
  of 
  the 
  deep-sea 
  fauna 
  in 
  the 
  

   present 
  oceans 
  may 
  in 
  some 
  measure 
  be 
  explained. 
  In 
  like 
  manner 
  

   the 
  pelagic 
  fauna 
  and 
  flora 
  of 
  the 
  ocean 
  are 
  most 
  probably 
  derived 
  origi- 
  

   nally 
  from 
  the 
  shore 
  and 
  shallow 
  water. 
  During 
  each 
  period 
  of 
  the 
  

   earth's 
  history 
  a 
  few 
  animals 
  and 
  plants 
  have 
  been 
  carried 
  to 
  sea, 
  and 
  

   have 
  ultimately 
  adopted 
  a 
  pelagic 
  mode 
  of 
  life. 
  

  

  Without 
  insisting 
  strongly 
  on 
  the 
  correctness 
  of 
  some 
  of 
  these 
  deduc- 
  

   tions 
  and 
  conclusions, 
  we 
  present 
  them 
  for 
  the 
  consideration 
  of 
  natural- 
  

   ists 
  and 
  geologists 
  as 
  the 
  result 
  of 
  a 
  long, 
  careful, 
  but 
  as 
  yet 
  incomplete 
  

   investigation. 
  

  

  