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  hylidti:. 
  

  

  the 
  heels 
  overlap, 
  and 
  the 
  tibio-tarsal 
  articulation 
  

   reaches 
  the 
  eye 
  or 
  between 
  the 
  eye 
  and 
  the 
  nostril. 
  

   Besides, 
  the 
  vocal 
  sac 
  is 
  larger, 
  and 
  the 
  voice 
  deeper, 
  

   whence 
  the 
  name 
  barytonus, 
  which 
  has 
  been 
  given 
  to 
  

   it 
  by 
  Heron-Royer. 
  

  

  Fig. 
  94. 
  

  

  Hind 
  limbs 
  of 
  Hyla 
  arbor 
  ea, 
  showing 
  variations 
  in 
  the 
  proportions 
  

   of 
  the 
  tibia 
  and 
  foot. 
  The 
  dotted 
  line 
  indicates 
  the 
  middle 
  line 
  

   of 
  the 
  body. 
  A. 
  $, 
  f. 
  typiea, 
  St. 
  Malo. 
  b. 
  $, 
  v. 
  Savignyi, 
  

   Jerusalem, 
  c. 
  $, 
  v. 
  meridionalis, 
  Cannes. 
  

  

  These 
  structural 
  differences 
  are, 
  however, 
  far 
  from 
  

   constant 
  ; 
  there 
  are 
  intermediate 
  forms, 
  as, 
  for 
  in- 
  

   stance, 
  the 
  var. 
  molleri, 
  which 
  Bedriaga 
  defines 
  as 
  a 
  

   H. 
  meridionalis 
  with 
  the 
  coloration 
  of 
  the 
  typical 
  form. 
  

   A 
  male 
  specimen 
  from 
  Ciudad 
  Real 
  may, 
  I 
  think, 
  be 
  

   referred 
  to 
  it; 
  the 
  heels 
  slightly 
  overlap, 
  the 
  tibia 
  

   measures 
  17 
  mm. 
  and 
  the 
  foot 
  15, 
  just 
  as 
  in 
  a 
  H. 
  meri- 
  

   dionalis, 
  but 
  the 
  coloration 
  is 
  that 
  of 
  the 
  typical 
  form, 
  

   and 
  the 
  specimen 
  was 
  identified 
  as 
  such 
  by 
  Bosca. 
  A 
  

   female 
  from 
  Coimbra, 
  received 
  from 
  Dr. 
  de 
  Bedriasra 
  

   himself, 
  agrees 
  in 
  the 
  proportion 
  of 
  the 
  limbs 
  : 
  tibia 
  

   22 
  mm., 
  foot 
  20. 
  

  

  A 
  glance 
  at 
  the 
  preceding 
  tables 
  of 
  measurements 
  

   suffices 
  to 
  show 
  that 
  the 
  difference 
  in 
  length 
  between 
  

   tibia 
  and 
  foot, 
  so 
  considerable 
  in 
  the 
  extremes, 
  is 
  

   bridged 
  over 
  in 
  such 
  a 
  manner 
  as 
  to 
  render 
  a 
  precise 
  

   definition 
  impossible. 
  The 
  same 
  may 
  be 
  said 
  of 
  the 
  

   development 
  of 
  the 
  vocal 
  sac. 
  We 
  have 
  therefore 
  to 
  

   fall 
  back 
  upon 
  the 
  coloration 
  for 
  diagnosing 
  the 
  three 
  

   forms, 
  and 
  this 
  is 
  surely 
  not 
  enough 
  to 
  justify 
  their 
  

   being 
  treated 
  as 
  species, 
  the 
  more 
  so 
  as 
  the 
  var. 
  

   savignyi 
  is 
  itself 
  a 
  connecting 
  link 
  between 
  the 
  typical 
  

  

  