﻿378 
  ANNUAL 
  EEPOET 
  SMITHSONIAN- 
  INSTITUTION, 
  192*7 
  

  

  from 
  year 
  to 
  year, 
  new 
  species 
  and 
  new 
  subspecies. 
  But 
  no 
  study 
  in 
  

   fish 
  groups 
  permits 
  the 
  distinction 
  of 
  subspecies 
  from 
  species 
  in 
  

   the 
  degree 
  now 
  possible 
  among 
  birds 
  or 
  mammals. 
  We 
  must 
  await 
  

   further 
  studies 
  for 
  a 
  consistent 
  trinomial 
  nomenclature 
  in 
  ichthy- 
  

   ology. 
  The 
  number 
  of 
  new 
  forms 
  now 
  discovered 
  each 
  year 
  is 
  

   often 
  less 
  than 
  the 
  number 
  of 
  recognized 
  species 
  which 
  are 
  each 
  

   year 
  proved 
  to 
  be 
  untenable. 
  Three 
  complete 
  lists 
  of 
  the 
  fresh-water 
  

   fishes 
  of 
  the 
  United 
  States 
  have 
  been 
  published 
  by 
  the 
  present 
  writer. 
  

   That 
  of 
  Jordan 
  and 
  Copeland^^ 
  in 
  1876 
  enumerates 
  670 
  species. 
  

   That 
  of 
  Jordan 
  ^^ 
  in 
  1878 
  contains 
  665 
  species, 
  and 
  that 
  of 
  Jordan 
  ^° 
  

   in 
  1885, 
  587 
  species, 
  although 
  upward 
  of 
  75 
  new 
  species 
  were 
  de- 
  

   tected 
  in 
  the 
  nine 
  years 
  which 
  elapsed 
  between 
  the 
  first 
  and 
  the 
  last 
  

   list. 
  Additional 
  specimens 
  from 
  intervening 
  localities 
  are 
  often 
  

   found 
  to 
  form 
  connecting 
  links 
  among 
  the 
  nominal 
  species, 
  and 
  

   thus 
  several 
  supposed 
  species 
  become 
  in 
  time 
  merged 
  in 
  one. 
  The 
  

   common 
  channel 
  catfish 
  ^^ 
  of 
  our 
  rivers 
  has 
  been 
  described 
  as 
  a 
  new 
  

   species 
  not 
  less 
  than 
  25 
  times, 
  on 
  account 
  of 
  differences 
  real 
  or 
  

   imaginary, 
  but 
  comparatively 
  trifling 
  in 
  value. 
  

  

  Where 
  species 
  can 
  readily 
  migrate, 
  their 
  uniformity 
  is 
  preserved; 
  

   but 
  whenever 
  a 
  form 
  becomes 
  localized 
  its 
  representatives 
  assume 
  

   some 
  characters 
  not 
  shared 
  by 
  the 
  species 
  as 
  a 
  whole. 
  When 
  we 
  

   can 
  trace, 
  as 
  we 
  often 
  can, 
  the 
  disappearance 
  by 
  degrees 
  of 
  these 
  

   characters, 
  such 
  forms 
  no 
  longer 
  represent 
  to 
  us 
  distinct 
  species. 
  In 
  

   cases 
  where 
  the 
  connecting 
  forms 
  are 
  extinct, 
  or 
  at 
  least 
  not 
  repre- 
  

   sented 
  in 
  collections, 
  each 
  form 
  which 
  is 
  apparently 
  different 
  must 
  be 
  

   regarded 
  as 
  a 
  distinct 
  species. 
  

  

  The 
  variations 
  in 
  any 
  type 
  become, 
  in 
  general, 
  more 
  marked 
  as 
  

   we 
  approach 
  the 
  Tropics. 
  The 
  genera 
  are 
  represented, 
  on 
  the 
  whole, 
  

   by 
  more 
  species 
  there, 
  and 
  it 
  would 
  appear 
  that 
  the 
  processes 
  of 
  

   specific 
  change 
  go 
  on 
  more 
  rapidly 
  under 
  the 
  conditions 
  of 
  life 
  in 
  the 
  

   Torrid 
  Zone. 
  

  

  We 
  recognize 
  now 
  in 
  North 
  America 
  25 
  distinct 
  species 
  of 
  fresh- 
  

   water 
  catfishes 
  ( 
  Ameiuridse) 
  , 
  although 
  93 
  nominal 
  species 
  of 
  these 
  

   fishes 
  have 
  been 
  from 
  time 
  to 
  time 
  described. 
  But 
  these 
  25 
  species 
  

   are 
  among 
  themselves 
  very 
  closely 
  related, 
  and 
  all 
  of 
  them 
  are 
  subject 
  

   to 
  a 
  variety 
  of 
  minor 
  changes. 
  It 
  requires 
  no 
  strong 
  effort 
  of 
  the 
  

   imagination 
  to 
  see 
  in 
  them 
  all 
  the 
  modified 
  descendants 
  of 
  some 
  one 
  

   species 
  of 
  catfish, 
  not 
  unlike 
  our 
  commoner 
  " 
  bull-head 
  " 
  {Ameiurus 
  

  

  28 
  Check 
  list 
  of 
  the 
  fishes 
  of 
  the 
  fresh 
  waters 
  of 
  north 
  America, 
  by 
  David 
  Starr 
  Jordan 
  

   and 
  Herbert 
  E. 
  Copeland. 
  Bull, 
  of 
  the 
  Buffalo 
  Society 
  of 
  Natural 
  History, 
  1876, 
  pp. 
  

   133-164. 
  

  

  =^A 
  catalogue 
  of 
  the 
  fishes 
  of 
  the 
  fresh 
  waters 
  of 
  North 
  America. 
  Bulletin 
  of 
  the 
  

   United 
  States 
  Geological 
  Survey, 
  1878, 
  pp. 
  407-442. 
  

  

  »"A 
  catalogue 
  of 
  the 
  fishes 
  known 
  to 
  inhabit 
  the 
  waters 
  of 
  North 
  America 
  north 
  of 
  

   the 
  T'lopic 
  of 
  Cancer. 
  Annual 
  Report 
  of 
  the 
  Commissioners 
  of 
  Fish 
  and 
  Fisheriea 
  for 
  

   1884 
  and 
  1885. 
  

  

  ^1 
  Ictalurus 
  punctatua. 
  

  

  