﻿4 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol.67 
  

  

  the 
  tongue 
  ends 
  in 
  two 
  main 
  branches, 
  tipped 
  with 
  heavy 
  spines 
  

   many 
  times 
  larger 
  than 
  the 
  marginal 
  spines. 
  In 
  this 
  type 
  of 
  tongue 
  

   there 
  is 
  a 
  definite 
  line 
  of 
  demarcation 
  between 
  the 
  fleshy 
  body 
  of 
  the 
  

   tongue 
  and 
  the 
  translucent 
  cornified 
  tip 
  which 
  is 
  frayed. 
  

  

  In 
  studying 
  such 
  a 
  tongue 
  for 
  factors 
  that 
  are 
  constant, 
  one 
  is 
  

   forced 
  to 
  conclude 
  that 
  beyond 
  the 
  general 
  shape 
  and 
  appearance 
  

   there 
  is 
  nothing 
  that 
  can 
  be 
  accepted 
  as 
  invariable. 
  The 
  number 
  

   of 
  posterior 
  spines 
  is 
  inconstant 
  within 
  the 
  species, 
  although 
  they 
  

   may 
  be 
  counted 
  on 
  to 
  be 
  in 
  a 
  single 
  row 
  (in 
  contradistinction 
  to 
  the 
  

   multiple 
  rows 
  as 
  seen 
  in 
  owls, 
  for 
  example) 
  . 
  

  

  The 
  length 
  depends 
  on 
  the 
  amount 
  of 
  wear. 
  In 
  a 
  series 
  of 
  meadow- 
  

   lark 
  tongues 
  collected 
  in 
  one 
  day 
  in 
  South 
  Dakota 
  the 
  length 
  varies 
  

   from 
  16 
  mm. 
  to 
  20.5 
  mm. 
  The 
  birds 
  were 
  feeding 
  almost 
  entirely 
  on 
  

   grasshoppers 
  that 
  were 
  at 
  that 
  time 
  a 
  serious 
  pest. 
  

  

  The 
  main 
  posterolateral 
  or 
  heaviest 
  spines 
  are 
  not 
  invariable 
  

   in 
  arrangement 
  ; 
  while 
  always 
  present 
  they 
  may 
  be 
  bifid 
  or 
  in 
  birds, 
  

   as 
  some 
  of 
  the 
  sparrows, 
  where 
  they 
  are 
  normally 
  split 
  into 
  two, 
  

   there 
  may 
  be 
  three 
  or 
  four 
  subdivisions. 
  

  

  The 
  curling, 
  splitting, 
  and 
  fraying 
  is 
  also 
  variable 
  within 
  the 
  

   species 
  and 
  shows 
  individual 
  modifications, 
  although, 
  as 
  will 
  be 
  seen 
  

   later, 
  these 
  characters 
  serve 
  as 
  very 
  important 
  adaptive 
  features 
  and 
  

   undergo 
  extensive 
  variations 
  in 
  certain 
  families. 
  

  

  Bearing 
  in 
  mind 
  these 
  inconstant 
  factors 
  it 
  is 
  of 
  interest 
  to 
  trace 
  

   the 
  modifications 
  that 
  may 
  be 
  found 
  of 
  this 
  fundamental 
  pattern. 
  

  

  With 
  slight 
  differences 
  in 
  curling, 
  splitting, 
  length, 
  and 
  arrange- 
  

   ment 
  of 
  spines 
  this 
  tongue 
  is 
  to 
  be 
  found 
  in 
  a 
  large 
  number 
  of 
  pas- 
  

   serine 
  birds, 
  as 
  the 
  warblers, 
  vireos, 
  thrushes, 
  thrashers, 
  crows, 
  fly- 
  

   catchers, 
  shrikes, 
  wrens, 
  bulbuls, 
  drongos, 
  and 
  the 
  like, 
  with 
  Glareola 
  

   closely 
  simulating 
  it. 
  The 
  divergence 
  from 
  the 
  type, 
  however, 
  is 
  

   most 
  marked 
  and 
  comes 
  to 
  its 
  greatest 
  development 
  in 
  the 
  flower- 
  

   frequenting 
  forms. 
  

  

  The 
  typical 
  tongue 
  has 
  an 
  inherent 
  tendency 
  to 
  curl, 
  split, 
  and 
  

   fray, 
  and 
  any 
  one 
  or 
  all 
  of 
  these 
  tendencies 
  may 
  be 
  combined 
  to 
  make 
  

   up 
  the 
  tongues 
  of 
  the 
  flower 
  frequenters. 
  

  

  Thus 
  splitting 
  alone 
  with 
  little 
  tendency 
  to 
  curl 
  and 
  no 
  fraying 
  

   is 
  exemplified 
  by 
  the 
  tongue 
  of 
  the 
  flowerpeckers 
  or 
  Dicaeidae, 
  which 
  

   is 
  deeply 
  split, 
  forming 
  very 
  slender 
  long 
  forked 
  tips, 
  two 
  in 
  Dicaeum 
  

   and 
  four 
  in 
  Prionochilus. 
  

  

  On 
  the 
  other 
  hand 
  marked 
  curling 
  is 
  seen 
  in 
  the 
  Old 
  World 
  sun- 
  

   birds 
  (Nectariniidae), 
  where 
  it 
  may 
  be 
  a 
  complete 
  tube 
  for 
  the 
  

   greater 
  part 
  of 
  its 
  length, 
  without 
  fraying 
  of 
  the 
  margins 
  of 
  the 
  

   tube 
  and 
  with 
  splitting 
  into 
  two 
  tips 
  either 
  absent 
  or 
  very 
  slight. 
  

   Whether 
  the 
  tongue 
  be 
  a 
  relatively 
  short 
  one, 
  as 
  in 
  Hermotimia 
  (fig. 
  

   141), 
  or 
  very 
  long 
  as 
  in 
  Arachnothera, 
  this 
  perfect 
  tubular 
  arrange- 
  

   ment 
  exists 
  in 
  the 
  anterior 
  two-thirds 
  of 
  each. 
  Splitting 
  is 
  not 
  

  

  