﻿110 
  INTEUDUCTION. 
  

  

  Millimetres. 
  

  

  7. 
  Hiila 
  arhored 
  50 
  

  

  8. 
  Rana 
  iberica 
  50 
  

  

  9. 
  Bomhinator 
  pachijpus 
  . 
  . 
  . 
  . 
  . 
  50 
  

  

  10. 
  liana 
  csciiJenta 
  125 
  > 
  

  

  11. 
  ,, 
  grdeca 
  66 
  

  

  12. 
  ,, 
  agilis 
  90 
  

  

  13. 
  5, 
  latastii 
  65 
  

  

  14. 
  „ 
  avvalis 
  75 
  

  

  15. 
  ,, 
  temporaria 
  95 
  

  

  16. 
  Bafo 
  vivid 
  is 
  90 
  

  

  17. 
  Discoglossus 
  pictus 
  75 
  

  

  18. 
  Bufo 
  calamita 
  80 
  

  

  19. 
  J, 
  vidgavis 
  .180 
  

  

  It 
  may 
  be 
  noticed 
  that 
  the 
  five 
  species 
  which 
  head 
  

   the 
  list 
  as 
  having 
  proportionally 
  the 
  largest 
  tadpoles 
  

   are 
  the 
  only 
  ones 
  in 
  which 
  the 
  pupil 
  is 
  vertical. 
  

  

  The 
  structural 
  differences 
  which 
  separate 
  the 
  genera 
  

   and 
  species 
  in 
  their 
  tadpole 
  condition 
  reflect, 
  on 
  the 
  

   whole, 
  pretty 
  accurately 
  the 
  system 
  based 
  upon 
  the 
  

   perfect 
  animals, 
  although 
  here 
  and 
  there 
  the 
  modifi- 
  

   cations 
  are 
  of 
  unequal 
  importance. 
  We 
  must 
  bear 
  in 
  

   mind, 
  however, 
  that 
  such 
  a 
  correspondence, 
  if 
  existing 
  

   in 
  the 
  European 
  Batrachians, 
  is 
  not 
  universal. 
  Larval 
  

   forms 
  such 
  as 
  the 
  tadpoles 
  are 
  outside 
  the 
  cycle 
  of 
  

   recapitulation, 
  the 
  ontogeny 
  being 
  broken 
  by 
  the 
  

   intercalation 
  of 
  the 
  larval 
  phasis. 
  The 
  horny 
  beak, 
  

   the 
  circular 
  lip 
  with 
  its 
  horuy 
  armature, 
  the 
  spi- 
  

   raculum, 
  the 
  enclosure 
  of 
  the 
  fore 
  limbs 
  in 
  diverticula 
  

   of 
  the 
  branchial 
  chambers, 
  and 
  such 
  special 
  adapta- 
  

   tions 
  as 
  the 
  ventral 
  disk 
  or 
  sucker 
  of 
  certain 
  exotic 
  

   mountain 
  forms, 
  clearly 
  point 
  to 
  tadpoles 
  having 
  

   had 
  a 
  developmental 
  history 
  of 
  their 
  own. 
  We 
  need, 
  

   therefore, 
  not 
  be 
  surprised 
  at 
  occasionally 
  finding, 
  

   within 
  the 
  same 
  genus, 
  very 
  different 
  types 
  of 
  tad- 
  

   poles, 
  or 
  even 
  a 
  total 
  suppression 
  of 
  the 
  free 
  larval 
  

   stages, 
  as 
  is 
  actually 
  the 
  case 
  in 
  the 
  large 
  and 
  widely 
  

   distributed 
  genus 
  Rana. 
  

  

  