﻿16 
  

  

  INTEODUOTION. 
  

  

  sions, 
  are 
  nevertheless 
  able 
  to 
  slowly 
  ascend 
  a 
  pane 
  of 
  

   glass. 
  

  

  In 
  most 
  of 
  our 
  genera 
  the 
  fourth 
  and 
  fifth 
  toes 
  are 
  

   cleft 
  almost 
  to 
  the 
  base, 
  and 
  the 
  metatarsal 
  portions 
  of 
  

   them 
  are 
  separated 
  by 
  the 
  web. 
  In 
  two 
  genera, 
  Biifo 
  

   and 
  Eyla, 
  this 
  is 
  not 
  the 
  case 
  ; 
  the 
  metatarsals 
  of 
  the 
  

   two 
  outer 
  toes 
  are 
  bound 
  together 
  by 
  the 
  common 
  

   integument, 
  the 
  angular 
  divergence 
  of 
  the 
  fifth 
  toe 
  

   proceeding 
  only 
  from 
  the 
  basal 
  phalanx, 
  as 
  may 
  be 
  

   seen 
  from 
  the 
  following 
  figures 
  (Fig. 
  6) 
  representing 
  

   the 
  foot 
  of 
  the 
  common 
  frog 
  and 
  that 
  of 
  the 
  tree- 
  

  

  frog. 
  

  

  Fig. 
  6. 
  

  

  A 
  B 
  

  

  Lower 
  surface 
  of 
  foot 
  of 
  Bana 
  temporaria 
  (a) 
  and 
  Hyla 
  arhorea 
  (b). 
  

  

  The 
  tree-frog 
  difiers 
  from 
  other 
  Batrachians 
  in 
  

   having 
  the 
  articulations 
  of 
  the 
  limbs, 
  especially 
  the 
  

   wrist, 
  marked 
  above 
  by 
  a 
  strong 
  fold, 
  reminding 
  one 
  

   of 
  the 
  arms 
  and 
  legs 
  of 
  a 
  jointed 
  ijapier-maclie 
  doll. 
  

  

  The 
  proportions 
  of 
  the 
  hind 
  limbs 
  to 
  the 
  body 
  are 
  

   best 
  appreciated 
  by 
  bending 
  the 
  limb 
  forwards 
  against 
  

   the 
  side, 
  and 
  ascertaining 
  the 
  position 
  of 
  the 
  tibio- 
  

   tarsal 
  or 
  tarso-metatarsal 
  articulation 
  ; 
  a 
  certain 
  allow- 
  

   ance 
  must, 
  however, 
  be 
  made 
  in 
  cases 
  when 
  the 
  abdo- 
  

   men 
  of 
  a 
  female 
  is 
  much 
  distended 
  with 
  ripe 
  ova. 
  A 
  

   convenient 
  method 
  of 
  appreciating 
  the 
  length 
  of 
  the 
  

   tibia 
  as 
  compared 
  to 
  the 
  femur 
  is 
  to 
  fold 
  the 
  limb 
  so 
  

   as 
  to 
  place 
  the 
  former 
  at 
  a 
  right 
  angle 
  to 
  the 
  axis 
  of 
  

   the 
  body, 
  as 
  shown 
  in 
  the 
  accompanying 
  figure 
  (Fig. 
  7) 
  ; 
  

   in 
  which 
  position 
  the 
  heels 
  (tibio-tarsal. 
  articulation) 
  

   meet 
  when 
  the 
  tibia 
  is 
  nearly 
  equal 
  to 
  the 
  thigh, 
  fail 
  

   to 
  meet 
  when 
  shorter, 
  or 
  overlap 
  when 
  longer. 
  

  

  