﻿92 
  INTJiODCJOTlON. 
  

  

  out 
  a 
  trace. 
  The 
  body 
  of 
  tlie 
  hyoid 
  cartilage 
  of 
  the 
  

   transformed 
  animal 
  is 
  composed 
  of 
  the 
  two 
  united 
  

   branchial 
  plates, 
  the 
  posterior 
  copula, 
  and 
  of 
  newly 
  

   formed 
  cartilage, 
  constituting 
  the 
  manubria 
  of 
  the 
  

   principal 
  cornua, 
  probably 
  derived 
  from 
  the 
  copula. 
  

  

  The 
  alar 
  and 
  postero-lateral 
  processes 
  are 
  new 
  

   formations 
  which 
  only 
  appear 
  comparatively 
  late. 
  

   The 
  so-called 
  ^^ 
  irrocessus 
  thyroidei^^ 
  [thyrohyals, 
  t] 
  

   have 
  nothing 
  to 
  do 
  with 
  the 
  branchial 
  processes 
  (nor 
  

   with 
  the 
  ceratobranchials 
  of 
  Parker, 
  which 
  Gaupp 
  

   terms 
  spicula), 
  but 
  are 
  remains 
  of 
  the 
  posterior 
  portion 
  

   of 
  the 
  larval 
  branchial 
  plates. 
  

  

  Thus, 
  of 
  the 
  larval 
  apparatus 
  nothing 
  is 
  preserved 
  

   but 
  the 
  hyal 
  arch, 
  and 
  a 
  portion 
  of 
  the 
  copula 
  and 
  of 
  

   the 
  two 
  branchial 
  plates. 
  

  

  Dr. 
  W. 
  Gr. 
  Eidewood 
  has 
  recently 
  investigated 
  the 
  

   development 
  of 
  the 
  hyobranchial 
  skeleton 
  of 
  Pelodytes, 
  

   and 
  the 
  careful 
  figures 
  he 
  has 
  drawn 
  are 
  reproduced 
  

   bere 
  with 
  his 
  kind 
  permission. 
  He 
  agrees 
  with 
  Gaupp 
  

   in 
  the 
  main 
  results, 
  but 
  shows 
  the 
  postero-lateral 
  

   process 
  to 
  be 
  the 
  persistent 
  proximal 
  portion 
  of 
  the 
  

   first 
  ceratobranchial. 
  

  

  In 
  Pelodytes 
  as 
  well 
  as 
  in 
  Pelobates 
  the 
  anterior 
  

   processes 
  are 
  expanded 
  and 
  bent 
  inwards, 
  and 
  the 
  

   cornua 
  become 
  broken, 
  the 
  anterior 
  portion 
  fusing 
  

   with 
  the 
  alar 
  processes, 
  whilst 
  the 
  posterior 
  becomes 
  

   free 
  from 
  the 
  hyoid 
  plate, 
  as 
  may 
  be 
  seen 
  on 
  Fig. 
  38. 
  

  

  In 
  order 
  to 
  complete 
  this 
  rapid 
  sketch 
  of 
  the 
  

   evolution 
  of 
  the 
  hyobranchial 
  apparatus, 
  which 
  is 
  of 
  

   great 
  importance 
  for 
  the 
  correct 
  understanding 
  of 
  the 
  

   hyoid 
  apparatus 
  in 
  the 
  perfect 
  form, 
  it 
  remains 
  to 
  

   notice 
  that 
  in 
  the 
  Biscoglossldx 
  the 
  first 
  copula 
  or 
  

   basihyal 
  is 
  of 
  much 
  larger 
  size 
  than 
  in 
  other 
  frogs, 
  

   and 
  persists 
  longer 
  ; 
  whilst 
  the 
  second 
  extends 
  farther 
  

   back, 
  and 
  completely 
  separates 
  the 
  hyobranchial 
  

   plates 
  from 
  each 
  other. 
  

  

  The 
  ossification 
  of 
  the 
  thyroid 
  processes 
  takes 
  place 
  

   only 
  after 
  transformation. 
  

  

  The 
  only 
  cranial 
  ossifications 
  to 
  develop 
  during 
  the 
  

  

  