﻿EXTERNAL 
  CHARACTERS. 
  13 
  

  

  Discoglossidx 
  (Fig. 
  3, 
  a) 
  ; 
  circular 
  and 
  entire 
  or 
  

   feebly 
  nicked 
  behind 
  in 
  the 
  Pelobatidse 
  and 
  Hyla 
  

   (Fig. 
  3, 
  c), 
  resembling 
  a 
  mushroom 
  when 
  thrust 
  out; 
  

   elliptical 
  or 
  pyriform 
  and 
  entire 
  in 
  Bufo 
  (Fig. 
  3, 
  b) 
  ; 
  

   oval 
  and 
  forked 
  behind 
  in 
  Bana 
  (Fig. 
  3, 
  d). 
  In 
  the 
  

   two 
  latter 
  genera 
  the 
  extensibility 
  of 
  the 
  tongue 
  is 
  so 
  

   great 
  that 
  a 
  large 
  specimen 
  is 
  able 
  to 
  seize 
  a 
  prey 
  two 
  

   inches 
  distant 
  from 
  it. 
  

  

  Owing 
  to 
  the 
  nature 
  of 
  the 
  skin 
  and 
  the 
  absence 
  of 
  

   true 
  ribs, 
  the 
  shape 
  of 
  the 
  body 
  varies 
  enormously 
  

   according 
  to 
  the 
  degree 
  of 
  moisture 
  of 
  the 
  sub- 
  

   cutaneous 
  sacs, 
  the 
  inflation 
  of 
  the 
  lungs, 
  or 
  the 
  

   condition 
  of 
  the 
  ovaries, 
  and 
  all 
  measurements 
  that 
  

   are 
  not 
  based 
  on 
  the 
  bony 
  framework 
  are 
  useless 
  for 
  

   systematic 
  purposes. 
  The 
  frogs 
  of 
  the 
  genus 
  Bana 
  

   appear 
  hump-backed 
  in 
  a 
  squatting 
  posture, 
  an 
  angle 
  

   being 
  produced 
  at 
  the 
  articulation 
  of 
  the 
  cylindrical 
  

   sacral 
  diapophyses 
  with 
  the 
  iha; 
  the 
  other 
  genera, 
  

   with 
  flattened 
  and 
  dilated 
  sacral 
  diapophyses, 
  have 
  a 
  

   rounded 
  back 
  when 
  at 
  rest, 
  as 
  may 
  be 
  seen 
  on 
  com- 
  

   paring 
  a 
  true 
  frog 
  with 
  a 
  toad 
  or 
  tree-frog. 
  The 
  

   vent, 
  or 
  cloaca! 
  opening, 
  is 
  a 
  small 
  rounded 
  orifice 
  at 
  

   the 
  very 
  posterior 
  extremity 
  of 
  the 
  body, 
  above 
  and 
  

   between 
  the 
  thighs. 
  

  

  The 
  fore 
  limb 
  is 
  divided 
  into 
  a 
  hrachium 
  or 
  arm, 
  an 
  

   antehracliium' 
  or 
  forearm, 
  and 
  a 
  maniis 
  or 
  hand 
  with 
  

   four 
  functional 
  fingers, 
  of 
  which 
  the 
  third 
  is 
  the 
  

   longest. 
  The 
  length 
  of 
  the 
  first 
  finger 
  as 
  compared 
  

   to 
  the 
  second 
  is 
  often 
  used 
  as 
  a 
  specific 
  character. 
  

   In 
  order 
  to 
  preclude 
  misunderstandings, 
  it 
  is 
  well 
  to 
  

   remark 
  that 
  when 
  the 
  first 
  finger 
  is 
  stated 
  to 
  extend 
  

   as 
  far 
  as 
  or 
  beyond 
  the 
  second, 
  the 
  two 
  are 
  taken 
  to 
  

   meet 
  halfway. 
  A 
  rudimentary 
  pollex 
  is 
  often 
  indicated 
  

   externally 
  by 
  a 
  tubercle 
  at 
  the 
  base 
  of 
  the 
  inner 
  finger 
  

   (Fig. 
  4, 
  A). 
  

  

  The 
  hind 
  limb 
  is 
  longer, 
  usually 
  very 
  much 
  longer, 
  

   than 
  the 
  fore 
  limb, 
  and 
  divided 
  into 
  four 
  distinct 
  

   segments 
  — 
  the 
  femur 
  or 
  thigh, 
  the 
  crus 
  or 
  tibia 
  , 
  or 
  

   leg, 
  the 
  tarsus, 
  and 
  the 
  jpes 
  or 
  foot. 
  Anatomically, 
  

  

  