﻿Swifts 
  and 
  Ilumming-hii'ds. 
  367 
  

  

  shaped 
  apterium 
  over 
  each 
  eye, 
  these 
  being, 
  so 
  far 
  as 
  material 
  

   has 
  been 
  examined, 
  peculiar 
  to 
  the 
  respective 
  groups 
  and 
  not 
  

   found 
  in 
  the 
  Swallows. 
  

  

  The 
  dorsal 
  tract 
  of 
  the 
  Swallow 
  is 
  an 
  inverted, 
  short- 
  

   armed 
  Y 
  ; 
  the 
  dorsal 
  tracts 
  of 
  the 
  Swift 
  and 
  Humming-bird 
  

   are 
  continuous 
  from 
  neck 
  to 
  rump, 
  with 
  a 
  spindle-shaped 
  

   apterium 
  in 
  its 
  centre. 
  Both 
  Swift 
  and 
  Humming-bird 
  have 
  

   apteria 
  on 
  the 
  nape 
  and 
  on 
  the 
  inferior 
  surface 
  of 
  the 
  neck, 
  and 
  

   although 
  Dr. 
  Shufeldt 
  says 
  these 
  are 
  " 
  never 
  present 
  in 
  the 
  

   Swifts 
  or 
  Swallows," 
  he 
  might, 
  had 
  he 
  examined 
  such 
  genera 
  

   as 
  Macropteryx 
  and 
  Collocalia, 
  have 
  Avritten 
  otherwise. 
  The 
  

   statement 
  that 
  the 
  black 
  pigment 
  spaces, 
  so 
  apparent 
  on 
  the 
  

   brachia 
  of 
  Swifts, 
  are 
  entirely 
  absent 
  in 
  Humming-birds 
  is 
  

   equally 
  erroneous, 
  for 
  they 
  are 
  present 
  in 
  such 
  forms 
  as 
  

   Campylopterus 
  and 
  Florisiiga. 
  On 
  the 
  whole, 
  the 
  ptery 
  loses 
  of 
  

   Swift 
  and 
  Humming-bird 
  are 
  more 
  alike 
  than 
  those 
  of 
  Swift 
  

   and 
  Swallow, 
  as 
  a 
  glance 
  at 
  the 
  figures 
  of 
  Nitzsch 
  will 
  show. 
  

  

  The 
  pterylosis 
  of 
  the 
  Humming-bird 
  is 
  one 
  of 
  the 
  prettiest 
  

   instances 
  of 
  adaptation 
  imaginable 
  : 
  the 
  nuchal 
  apteria 
  come 
  

   where 
  the 
  neck 
  touches 
  the 
  back 
  and 
  breast, 
  the 
  lateral 
  

   apteria 
  receive 
  the 
  folded 
  wings, 
  and 
  the 
  ventral 
  apterium 
  

   allows 
  the 
  warm 
  body 
  to 
  come 
  in 
  contact 
  with 
  the 
  eggs. 
  

  

  It 
  seems 
  almost 
  superfluous 
  to 
  refer 
  to 
  the 
  sternum, 
  this 
  

   bone 
  having 
  been 
  so 
  often 
  .discussed; 
  but 
  as 
  it 
  is 
  implied 
  that 
  

   undue 
  stress 
  has 
  been 
  laid 
  upon 
  the 
  un-notched 
  character 
  of 
  

   the 
  posterior 
  border 
  of 
  the 
  Swift^s 
  sternum, 
  it 
  may 
  be 
  well 
  

   to 
  say 
  that 
  the 
  value 
  of 
  this 
  portion 
  of 
  the 
  sternum 
  is 
  small 
  

   when 
  compared 
  with 
  that 
  of 
  its 
  other 
  portions, 
  and 
  in 
  the 
  

   present 
  instance 
  may 
  well 
  be 
  omitted. 
  

  

  The 
  Swallow, 
  in 
  common 
  with 
  all 
  Passerine 
  birds, 
  has 
  a 
  

   large 
  Y-shaped 
  manubrium, 
  grooves 
  for 
  the 
  coracoids, 
  and 
  

   large 
  costal 
  processes 
  to 
  which 
  the 
  ribs 
  are 
  attached. 
  The 
  

   sternum 
  of 
  the 
  Humming-bird 
  has 
  a 
  rudimentary 
  manubrium 
  

   and 
  costal 
  processes, 
  elliptical 
  facets 
  for 
  the 
  coracoids, 
  and 
  the 
  

   ribs 
  are 
  joined 
  to 
  its 
  sides, 
  all 
  of 
  this 
  being 
  equally 
  true 
  of 
  

   the 
  sternum 
  of 
  the 
  Swift, 
  except 
  that 
  the 
  costal 
  processes 
  

   are 
  a 
  shade 
  larger 
  and 
  may 
  bear 
  one, 
  or, 
  as 
  in 
  Macropteryx, 
  

   even 
  two 
  ri))s. 
  

  

  