﻿On 
  the 
  occurrence 
  of 
  the 
  Caspian 
  Tern 
  (Sylochelidon 
  Caspius) 
  

   in 
  North 
  America. 
  — 
  By 
  Geo. 
  N. 
  Lawrence. 
  Read 
  May 
  

   6th, 
  1850. 
  

  

  The 
  similarity 
  in 
  color 
  which 
  prevails 
  in 
  this 
  class 
  of 
  birds 
  

   in 
  all 
  their 
  changes 
  of 
  plumage, 
  is 
  a 
  source 
  of 
  much 
  difficulty 
  

   in 
  determining 
  such 
  as 
  approach 
  each 
  other 
  in 
  size 
  ; 
  it 
  now 
  

   appears 
  that 
  two 
  distinct 
  species 
  found 
  in 
  the 
  United 
  States, 
  

   have 
  been 
  recognized 
  as 
  the 
  " 
  Sterna 
  Cayana 
  " 
  of 
  Latham, 
  

   whereas 
  the 
  existence 
  of 
  that 
  species 
  among 
  our 
  birds 
  is 
  now 
  

   doubted. 
  

  

  Mr. 
  Gambel, 
  of 
  Philadelphia, 
  has 
  described 
  one 
  of 
  these, 
  

   (in 
  the 
  Proceedings 
  of 
  the 
  Acad, 
  of 
  Sciences 
  of 
  Dec, 
  1848,) 
  

   under 
  the 
  name 
  of 
  " 
  Sterna 
  Regia," 
  and" 
  remarks, 
  " 
  This 
  no- 
  

   ble 
  species, 
  so 
  abundant 
  on 
  our 
  southern 
  coast, 
  has 
  for 
  a 
  long 
  

   time 
  been 
  considered 
  the 
  Sterna 
  Cayana 
  of 
  Latham." 
  

  

  The 
  other 
  is 
  the 
  subject 
  of 
  this 
  communication, 
  I 
  have 
  

   possessed 
  specimens 
  of 
  these 
  Terns 
  for 
  several 
  years 
  ; 
  both 
  

   kinds 
  were 
  killed 
  on 
  the 
  coast 
  of 
  Long 
  Island. 
  Others 
  as 
  

   well 
  as 
  myself 
  heretofore 
  considered 
  them 
  to 
  be 
  Cayenne 
  

   Terns. 
  

  

  After 
  reading 
  Mr. 
  Gambel's 
  account 
  of 
  his 
  S. 
  regia, 
  I 
  ex- 
  

   amined 
  ray 
  specimens 
  more 
  critically, 
  and 
  found 
  the 
  smaller 
  

   of 
  the 
  two 
  corresponded 
  with 
  his 
  description 
  ; 
  the 
  other 
  was 
  

   much 
  larger, 
  exceeding 
  it 
  in 
  length 
  over 
  two 
  inches, 
  although 
  

   the 
  tail 
  measured 
  one 
  and 
  a 
  half 
  inches 
  less. 
  

  

  1 
  took 
  notes 
  of 
  its 
  dimensions, 
  &o., 
  but 
  deferred 
  publish- 
  

   ing 
  an 
  account 
  of 
  it, 
  till 
  I 
  could 
  investigate 
  it 
  more 
  fully 
  by 
  

   a 
  comparison 
  with 
  the 
  Terns 
  in 
  the 
  Philadelphia 
  Academy. 
  

  

  Recently 
  my 
  attention 
  was 
  called 
  to 
  a 
  fine 
  specimen, 
  re- 
  

   ceived 
  from 
  the 
  coast 
  of 
  New- 
  Jersey 
  by 
  Mr. 
  Nicolas 
  Pike, 
  of 
  

   Brooklyn, 
  which 
  he 
  considered 
  iJentical 
  with 
  the 
  Caspian 
  Tern 
  

   of 
  Europe, 
  as 
  it 
  corresponded 
  with 
  the 
  description 
  of 
  that 
  spe- 
  

   cies 
  in 
  " 
  Yarrell's 
  British 
  Birds." 
  

  

  Since 
  then 
  T 
  have 
  had 
  an 
  opportunity 
  of 
  seeing 
  a 
  specimen 
  

  

  