﻿DISTRIBUTION 
  OF 
  FISHES 
  JORDAN 
  381 
  

  

  reported 
  from 
  China 
  {Avieiurus 
  cantonensis) 
  is 
  probably 
  based 
  on 
  a 
  

   specimen 
  carried 
  over 
  from 
  America. 
  

  

  The 
  suckers 
  are 
  modified 
  Cyprinidae, 
  probably 
  developed 
  in 
  

   America, 
  although 
  one 
  species 
  has 
  spread 
  from 
  Alaska 
  to 
  Siberia 
  

   and 
  another 
  very 
  peculiar 
  form 
  exists 
  in 
  China. 
  Whatever 
  its 
  

   origin, 
  this 
  group 
  is 
  now 
  one 
  of 
  the 
  most 
  characteristic 
  of 
  our 
  fauna. 
  

  

  The 
  Cyprinidce 
  of 
  western 
  America 
  are 
  more 
  or 
  less 
  closely 
  related 
  

   to 
  Old 
  World 
  types, 
  and 
  some 
  of 
  them, 
  like 
  the 
  Old 
  World 
  species, 
  

   reach 
  a 
  great 
  size. 
  East 
  of 
  the 
  Rocky 
  Mountains 
  are 
  found 
  a 
  multi- 
  

   tude 
  of 
  species, 
  mostly 
  of 
  small 
  size 
  and 
  weak 
  organization, 
  which 
  

   seem 
  mostly 
  to 
  be 
  degenerates 
  or 
  reduced 
  representatives 
  of 
  Euro- 
  

   pean 
  types, 
  though 
  for 
  the 
  most 
  part 
  hliving 
  no 
  immediate 
  relatives 
  

   among 
  the 
  latter. 
  The 
  majority 
  of 
  these 
  species 
  belong 
  to 
  a 
  group 
  

   of 
  genera 
  often 
  united 
  with 
  Notropis^ 
  which 
  is 
  found 
  only 
  in 
  America, 
  

   and 
  is 
  one 
  of 
  the 
  most 
  characteristic 
  of 
  our 
  fish 
  fauna. 
  

  

  The 
  characins 
  belong 
  to 
  the 
  Tropics, 
  especially 
  to 
  South 
  America. 
  

   The 
  single 
  species 
  which 
  crosses 
  the 
  Rio 
  Grande 
  is 
  an 
  immigrant 
  

   from 
  Mexico. 
  The 
  same 
  remarks 
  apply 
  also 
  to 
  the 
  cichlids, 
  a 
  group 
  

   especially 
  characteristic 
  of 
  tropical 
  America, 
  one 
  species 
  of 
  which 
  

   reaches 
  southern 
  Texas. 
  

  

  The 
  moon-eyes 
  are 
  characteristically 
  American 
  types, 
  with 
  no 
  near 
  

   relatives 
  elsewhere 
  in 
  the 
  world. 
  Their 
  ancestors 
  were 
  probably 
  

   relics 
  of 
  the 
  Cretaceous 
  marine 
  fauna. 
  

  

  The 
  herring 
  permanently 
  resident 
  in 
  our 
  fresh 
  waters 
  were 
  origi- 
  

   nally 
  landlocked 
  representatives 
  of 
  forms 
  still 
  found 
  in 
  the 
  sea 
  

   along 
  our 
  coasts. 
  Some 
  species, 
  as 
  the 
  shad, 
  are 
  anadromous, 
  ascend- 
  

   ing 
  rivers 
  in 
  the 
  spring. 
  

  

  The 
  gizzard 
  shad 
  is 
  indifferently 
  marine, 
  anadromous, 
  or 
  land- 
  

   locked, 
  and 
  is 
  still 
  extending 
  its 
  range 
  in 
  sluggish 
  waters 
  through 
  the 
  

   agency 
  of 
  canals. 
  

  

  The 
  various 
  forms 
  of 
  salmon 
  and 
  white-fish 
  abound 
  in 
  the 
  streams 
  

   and 
  lakes 
  of 
  all 
  northern 
  regions. 
  The 
  larger 
  species 
  are 
  marine 
  and 
  

   anadromous, 
  the 
  smaller 
  confined 
  to 
  lakes 
  and 
  brooks; 
  but 
  all 
  seek 
  

   streams 
  or 
  at 
  least 
  shallower 
  waters 
  for 
  the 
  purpose 
  of 
  spawning, 
  

   and 
  all 
  which 
  can 
  do 
  so 
  enter 
  the 
  sea, 
  becoming 
  "salmon 
  trout" 
  or 
  

   ' 
  steelheads." 
  The 
  whole 
  group 
  had 
  probably 
  a 
  marine 
  origin; 
  the 
  

   more 
  strictly 
  fresh-water 
  species 
  being, 
  as 
  is 
  usually 
  the 
  case, 
  smaller 
  

   in 
  size, 
  weaker 
  in 
  organization, 
  and 
  with 
  feebler 
  dentition. 
  It 
  is 
  often 
  

   assumed 
  that 
  this 
  group 
  had 
  its 
  origin 
  in 
  the 
  Atlantic, 
  most 
  likely 
  in 
  

   Europe, 
  but 
  equally 
  great 
  variety 
  appears 
  in 
  the 
  Northern 
  Pacific. 
  

  

  The 
  trout 
  perch 
  show 
  a 
  curious 
  combination 
  of 
  characters 
  of 
  spiny 
  

   and 
  soft-rayed 
  fishes. 
  The 
  two 
  or 
  three 
  species 
  are 
  no 
  doubt, 
  as 
  sug- 
  

   gested 
  by 
  Agassiz, 
  relics 
  of 
  an 
  ancient 
  fauna. 
  

  

  