﻿OF 
  THE 
  MORAY 
  FIRTH 
  AREA. 
  

  

  257 
  

  

  to 
  be 
  marked 
  off 
  by 
  sutures 
  behind 
  the 
  middle 
  of 
  the 
  bone, 
  and 
  

   not 
  bearing 
  any 
  teeth 
  in 
  that 
  part. 
  

  

  In 
  the 
  Holoptychiida>, 
  Rhizodontida?, 
  and 
  Osteolepida; 
  (Rhipidistia, 
  

   Cope, 
  emend. 
  Smith 
  Woodward) 
  the 
  hard 
  palate 
  is 
  fanned 
  by 
  one 
  large 
  

   bone, 
  extending 
  from 
  the 
  quadrate 
  articulation 
  of 
  the 
  jaw 
  behind 
  to 
  the 
  

   bones 
  in 
  front, 
  to 
  the 
  lower 
  and 
  outer 
  margin 
  of 
  which 
  is 
  articulated 
  in 
  

   Eusthenopteron 
  a 
  row 
  of 
  narrow 
  tooth-bearing 
  plates, 
  corresponding 
  to 
  the 
  

   internal 
  dentaries 
  of 
  the 
  opposed 
  mandible. 
  I 
  have 
  no 
  doubt 
  that 
  the 
  

   same 
  arrangement 
  prevails 
  in 
  all 
  these 
  families, 
  though 
  in 
  the 
  Osteolepidae 
  

   we 
  may 
  expect 
  the 
  tooth-bearing 
  ossicles 
  to 
  be 
  anchylosed 
  to 
  the 
  palato- 
  

   pterygoid. 
  

  

  The 
  only 
  other 
  fossil 
  in 
  my 
  collection 
  attributable 
  to 
  the 
  species 
  

   under 
  consideration 
  is 
  the 
  impression 
  of 
  the 
  inner 
  surface 
  of 
  a 
  large 
  

   jugular 
  plate, 
  7 
  inches 
  in 
  length 
  by 
  2| 
  in 
  breadth, 
  but 
  which 
  is, 
  

   I 
  rather 
  think, 
  imperfect 
  anteriorly. 
  It 
  certainly 
  does 
  not 
  belong 
  

   to 
  Holoptychius, 
  as 
  it 
  has 
  not 
  the 
  triangular 
  shape 
  characteristic 
  of 
  

   the 
  jugulars 
  in 
  that 
  genus, 
  and 
  as 
  its 
  shape, 
  on 
  the 
  other 
  hand, 
  

   reminds 
  us 
  of 
  that 
  of 
  the 
  corresponding 
  plate 
  in 
  Bhizodus, 
  it 
  seems 
  

   extremely 
  probable 
  that 
  it 
  appertains 
  to 
  the 
  same 
  species 
  as 
  the 
  

   one 
  under 
  consideration. 
  

  

  The 
  determination 
  of 
  the 
  Upper 
  Devonian 
  Rhizodontidrc 
  of 
  Scot- 
  

   land 
  and 
  Russia 
  is 
  a 
  matter 
  of 
  great 
  difficulty, 
  owing 
  to 
  the 
  fragmen- 
  

   tary 
  condition 
  in 
  which 
  their 
  remains 
  are 
  found. 
  The 
  present 
  jaws 
  

   have 
  a 
  considerable 
  resemblance 
  to 
  those 
  from 
  the 
  Upper 
  Old 
  Red 
  

   of 
  Clashbennie 
  in 
  Perthshire, 
  named 
  by 
  Agassiz 
  Bothriolepis 
  favosa, 
  

   and 
  doubtfully 
  referred 
  by 
  Smith 
  Woodward 
  to 
  Hall's 
  genus 
  

   Sauripterus 
  (47, 
  p. 
  363), 
  from 
  the 
  Catskill 
  (Upper 
  Old 
  Red) 
  forma- 
  

   tion 
  of 
  Pennsylvania. 
  But 
  in 
  the 
  jaws 
  both 
  from 
  Clashbennie 
  and 
  

   Pennsylvania 
  the 
  teeth 
  are 
  two-edged 
  to 
  the 
  base, 
  so 
  that 
  if 
  this 
  

   is 
  to 
  be 
  retained 
  as 
  a 
  generic 
  character, 
  the 
  allocation 
  of 
  the 
  Nairn 
  

   jaws 
  must 
  be 
  sought 
  elsewhere. 
  But 
  in 
  the 
  Upper 
  Devonian 
  

   rocks 
  of 
  Russia 
  there 
  occur 
  Rhizodont 
  remains 
  with 
  teeth 
  rounded 
  

   in 
  transverse 
  section, 
  to 
  which 
  Pander 
  gave 
  the 
  name 
  Polyplocuiu^ 
  

   under 
  the 
  idea 
  that 
  they 
  were 
  identical 
  with 
  Agassiz's 
  Crieudus, 
  

   which 
  latter 
  name 
  he 
  rejected 
  as 
  unsuitable 
  (35, 
  p. 
  28). 
  As 
  it 
  is 
  

   not 
  now 
  considered 
  allowable 
  to 
  alter 
  an 
  author's 
  generic 
  name 
  on 
  

   account 
  of 
  unsuitability, 
  real 
  or 
  supposed, 
  these 
  teeth 
  and 
  jaws 
  

   have 
  been 
  referred 
  to 
  'Cricodus' 
  by 
  Rohon, 
  1 
  Trautschold, 
  1 
  and 
  

  

  1 
  Mim. 
  Acad. 
  Imp. 
  Sci. 
  St. 
  Peter«hoimj 
  (7), 
  vol. 
  xxxvi., 
  No. 
  14, 
  lsv». 
  j>. 
  «!• 
  

   1 
  Zeitschr. 
  deutach. 
  yeof. 
  Cewlhrha/t, 
  vol. 
  xli., 
  1NH0, 
  p. 
  til*), 
  PI. 
  xxiii.-xxv. 
  

  

  VOL. 
  II. 
  ■ 
  

  

  