﻿DEVELOPMENT 
  AND 
  METAMORPHOSIS. 
  91 
  

  

  The 
  ceratoliyal 
  cartilage 
  at 
  first 
  articulates 
  by 
  a 
  

   condyle 
  with 
  the 
  suspensorium 
  below 
  its 
  prgeorbital 
  

   process, 
  and 
  extends 
  across 
  the 
  gular 
  region 
  towards 
  its 
  

   fellow, 
  from 
  which 
  it 
  is 
  separated 
  by 
  a 
  narrow 
  space, 
  

   with 
  one 
  or 
  two 
  small 
  cartilaginous 
  pieces 
  (basihyals, 
  

   Parker; 
  cojjtdde, 
  Gaupp), 
  behind 
  which 
  is 
  a 
  paired 
  

   plate 
  {hyobranchials^ 
  Parker; 
  hrancliial 
  ^late^ 
  Glaupp). 
  

   To 
  each 
  branchial 
  plate 
  the 
  four 
  cartilaginous 
  arches 
  

   bearing 
  the 
  tufted 
  internal 
  gills 
  are 
  attached 
  by 
  con- 
  

   nective 
  tissue, 
  and 
  ultimately 
  fuse 
  with 
  it 
  (in 
  the 
  third 
  

   period). 
  The 
  homology 
  of 
  these 
  branchial 
  arches 
  

   has 
  been 
  the 
  subject 
  of 
  much 
  discussion. 
  According 
  

   to 
  Parker, 
  they 
  are 
  to 
  be 
  regarded 
  as 
  subcutaneous 
  

   cartilages, 
  and 
  do 
  not 
  belong 
  to 
  the 
  category 
  of 
  true 
  

   visceral 
  arches 
  ; 
  they 
  are 
  called 
  accordingly 
  extra- 
  

   hranchials 
  — 
  the 
  true 
  branchial 
  arches 
  of 
  fishes 
  and 
  

   tailed 
  Batrachians 
  being 
  the 
  ceratohranchialSi 
  repre- 
  

   sented 
  by 
  small 
  styliform 
  cartilages 
  first 
  attached 
  to 
  

   the 
  outer 
  border 
  of 
  the 
  hyobranchial 
  cartilage, 
  with 
  

   which 
  they 
  fuse, 
  the 
  fourth 
  to 
  persist 
  throughout 
  life, 
  

   and 
  ossify 
  as 
  the 
  thyrohyal. 
  This 
  view 
  is 
  strongly 
  

   refuted 
  by 
  the 
  latest 
  worker 
  on 
  the 
  subject, 
  Gaupp, 
  

   whose 
  conclusions 
  are 
  as 
  follows 
  : 
  

  

  The 
  hyobranchial 
  apparatus 
  of 
  the 
  larva 
  consists 
  

   of 
  two 
  hyalia 
  [= 
  ceratohyals] 
  (Fig. 
  38, 
  ch), 
  con- 
  

   nected 
  mesially 
  by 
  a 
  pars 
  reuniens 
  ; 
  continuous 
  with 
  

   it 
  follows 
  the 
  copula 
  [basihyal, 
  hli\, 
  which 
  connects 
  

   the 
  hyal 
  with 
  the 
  branchial 
  skeleton. 
  The 
  latter 
  is 
  

   made 
  up 
  of 
  two 
  branchial 
  plates 
  [hyobranchials, 
  /i6r] 
  

   and 
  four 
  hrancliialia 
  [ceratobranchials, 
  chr~\ 
  on 
  each 
  

   side, 
  which 
  pass 
  into 
  the 
  branchial 
  plates 
  with 
  their 
  

   inner 
  extremities 
  and 
  into 
  each 
  other 
  with 
  their 
  

   dorso-lateral 
  extremities. 
  The 
  whole 
  hyobranchial 
  

   skeleton 
  forms 
  a 
  cartilaginous 
  continuum. 
  For 
  a 
  

   time 
  a 
  cartilaginous 
  piece 
  is 
  developed 
  in 
  front 
  of 
  the 
  

   pars 
  reuniens, 
  which 
  maybe 
  regarded 
  as 
  S; 
  first 
  copula. 
  

   During 
  metamorphosis 
  the 
  larval 
  apparatus 
  is 
  for 
  the 
  

   greater 
  part 
  lost; 
  the 
  pars 
  reuniens 
  and 
  the 
  anterior 
  

   copula 
  are 
  absorbed 
  ; 
  the 
  branchialia 
  disappear 
  with- 
  

  

  