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  THE 
  EXTINCT 
  VERTEBRATE 
  ANIMALS 
  

  

  family. 
  Before 
  discussing 
  its 
  generic 
  position, 
  it 
  will 
  be 
  better 
  

   first 
  to 
  describe 
  the 
  remains 
  themselves. 
  

  

  I 
  have 
  represented 
  in 
  PL 
  vii. 
  fig. 
  1, 
  natural 
  size, 
  the 
  most 
  

   perfect 
  of 
  these 
  mandibles 
  which 
  I 
  have 
  as 
  yet 
  obtained 
  ; 
  others, 
  

   more 
  fragmentary, 
  are 
  in 
  my 
  private 
  collection, 
  some 
  of 
  which 
  

   indicate 
  a 
  larger, 
  others 
  a 
  smaller 
  fish. 
  In 
  their 
  anteriorly 
  

   tapering 
  form 
  these 
  mandibles 
  differ 
  somewhat 
  from 
  the 
  under 
  

   jaws 
  of 
  other 
  members 
  of 
  the 
  family, 
  such 
  as 
  Eusthenopteron, 
  

   Rhizodus, 
  Bhizodopsis, 
  etc., 
  but 
  the 
  stumps 
  of 
  teeth 
  which 
  they 
  

   show 
  on 
  their 
  upper 
  margins, 
  both 
  small 
  and 
  laniary, 
  show 
  a 
  

   plicated 
  structure 
  of 
  the 
  base, 
  which 
  is 
  unmistakably 
  rhizodont 
  in 
  

   character. 
  As 
  this 
  plicated 
  structure 
  is 
  also 
  common 
  to 
  most 
  of 
  

   the 
  Stegocephalous 
  Amphibia, 
  one 
  might 
  almost 
  imagine 
  from 
  the 
  

   tapering 
  form 
  of 
  the 
  jaw 
  here 
  figured, 
  that 
  we 
  had 
  to 
  do 
  with 
  a 
  

   'Labyrinthodont,' 
  and 
  not 
  with 
  a 
  fish, 
  but 
  the 
  arrangement 
  of 
  the 
  

   larger 
  and 
  smaller 
  teeth, 
  along 
  with 
  the 
  apparent 
  construction 
  of 
  

   the 
  mandible 
  out 
  of 
  very 
  numerous 
  pieces, 
  leaves 
  no 
  doubt 
  in 
  my 
  

   mind 
  as 
  to 
  the 
  correctness 
  of 
  the 
  position 
  to 
  which 
  I 
  have 
  referred 
  

   it. 
  The 
  margin 
  of 
  the 
  jaw 
  is 
  set 
  with 
  an 
  external 
  row 
  of 
  small 
  

   teeth, 
  and 
  internally 
  to 
  those 
  are 
  seen 
  larger 
  laniaries, 
  one 
  of 
  

   which 
  is 
  exposed 
  in 
  the 
  specimen 
  figured, 
  while 
  in 
  another 
  

   example 
  their 
  stumps 
  may 
  be 
  seen 
  to 
  occur 
  in 
  pairs, 
  and 
  to 
  be 
  

   slightly 
  incurved. 
  Unfortunately, 
  none 
  of 
  the 
  teeth 
  are 
  quite 
  

   perfect, 
  but, 
  as 
  far 
  as 
  can 
  be 
  seen, 
  their 
  shafts 
  were 
  rounded 
  in 
  

   transverse 
  section 
  and 
  not 
  two-edged. 
  In 
  no 
  case 
  is 
  the 
  external 
  

   ornament 
  of 
  the 
  bones 
  of 
  the 
  jaw 
  visible. 
  

  

  In 
  Fig. 
  2 
  of 
  the 
  same 
  Plate 
  a 
  rhizodont 
  palato-pterygoid 
  bone 
  

   of 
  a 
  peculiarly 
  elongated 
  shape 
  is 
  depicted, 
  and 
  I 
  feel 
  no 
  doubt 
  

   that 
  it 
  belonged 
  to 
  the 
  same 
  species 
  as 
  the 
  above 
  described 
  

   mandibles. 
  It 
  is 
  seen 
  from 
  the 
  convex 
  palatal 
  surface, 
  and 
  the 
  

   greater 
  part 
  of 
  the 
  bone 
  has 
  splintered 
  off, 
  except 
  at 
  the 
  extremi- 
  

   ties 
  and 
  along 
  the 
  margins. 
  The 
  bone 
  itself 
  measures 
  6J 
  inches 
  

   in 
  length, 
  but 
  as 
  its 
  anterior 
  extremity 
  is 
  broken 
  off, 
  it 
  must 
  have 
  

   originally 
  been 
  at 
  least 
  one 
  inch 
  longer. 
  Along 
  the 
  anterior 
  half 
  

   of 
  the 
  lower 
  margin 
  are 
  seen 
  some 
  remains 
  of 
  the 
  roots 
  of 
  small 
  

   rhizodont 
  teeth 
  which 
  seem 
  to 
  have 
  been 
  borne, 
  as 
  I 
  have 
  shown 
  

   to 
  have 
  been 
  the 
  case 
  in 
  Eusthenopteron, 
  1 
  above 
  a 
  row 
  of 
  narrow 
  

   palato-marginal 
  ossicles, 
  of 
  which 
  two 
  are 
  distinctly 
  enough 
  seen 
  

   Geol 
  Mag. 
  (3), 
  vol. 
  x., 
  1893, 
  p. 
  266. 
  

  

  