﻿FROM 
  THE 
  KEUPER 
  SANDSTONE 
  OF 
  WARWICK. 
  433 
  

  

  in 
  the 
  mucous 
  canal 
  as 
  far 
  as 
  about 
  the 
  centre 
  of 
  the 
  fragment. 
  It 
  

   is 
  continued 
  thence 
  to 
  the 
  internal 
  angle 
  of 
  the 
  auditory 
  notch. 
  

  

  The 
  two 
  adjacent 
  pieces 
  have 
  apparently 
  been 
  detacbed 
  from 
  each 
  

   otber, 
  their 
  opposed 
  ends 
  being 
  originally 
  continuous. 
  Thus 
  united, 
  

   the 
  fragment 
  would 
  seem 
  to 
  represent 
  the 
  epiotic 
  and 
  some 
  adjoining 
  

   bones 
  ; 
  but 
  the 
  means 
  of 
  comparison 
  are 
  inadequate, 
  and 
  I 
  cannot 
  be 
  

   sure 
  that 
  this 
  is 
  the 
  true 
  interpretation. 
  

  

  Plate 
  47. 
  

  

  Casts 
  only 
  of 
  this 
  interesting 
  jaw 
  are 
  preserved. 
  Microscopical 
  

   examination 
  of 
  the 
  teeth 
  is 
  therefore 
  impossible. 
  The 
  casts 
  do 
  not 
  

   exhibit 
  the 
  condyle 
  or 
  postarticular 
  process, 
  which 
  would 
  probably 
  

   have 
  yielded 
  distinctive 
  characters. 
  The 
  fossil 
  cannot, 
  I 
  believe, 
  be 
  

   certainly 
  identified 
  with 
  Mastodonsaurus 
  giganteus, 
  Jager, 
  which 
  

   differs 
  in 
  its 
  sculpturing. 
  

  

  "We 
  are 
  now 
  in 
  a 
  position 
  to 
  sum 
  up 
  the 
  species 
  of 
  Labyrintho- 
  

   donts 
  hitherto 
  discovered 
  in 
  the 
  Keuper 
  Sandstone 
  of 
  Warwick. 
  

   Prof. 
  Owen's 
  list* 
  runs 
  thus 
  : 
  — 
  " 
  Labyrinihodon 
  Jcegeri, 
  L. 
  pachy- 
  

   gnaihus, 
  L. 
  leplognathus, 
  L. 
  ventricosus, 
  L. 
  scutulatus." 
  

  

  Of 
  these 
  species 
  L. 
  ventricosus 
  is 
  based 
  upon 
  a 
  slight 
  modification 
  

   of 
  tooth-structure. 
  The 
  position 
  in 
  the 
  skull 
  of 
  the 
  tooth 
  examined 
  

   is 
  unknown 
  ; 
  and 
  no 
  part 
  of 
  the 
  skeleton 
  has 
  been 
  identified. 
  There 
  

   is, 
  I 
  believe, 
  no 
  ground 
  for 
  affirming 
  the 
  distinctness 
  of 
  this 
  species. 
  

   L. 
  scutulatus 
  has 
  not 
  been 
  proved 
  to 
  be 
  Labyrinthodont 
  ; 
  and 
  there 
  

   are 
  reasons 
  of 
  weight 
  against 
  such 
  a 
  determination. 
  "We 
  have 
  found 
  

   it 
  necessary 
  to 
  revert 
  to 
  Jager's 
  genus 
  Mastodonsaurus, 
  retaining 
  at 
  

   the 
  same 
  time 
  Prof. 
  Owen's 
  quite 
  distinct 
  genus 
  Labyrinihodon. 
  

   Adding 
  the 
  new 
  genus 
  and 
  species 
  (Diadetognathus 
  varvicensis), 
  we 
  

   get 
  the 
  following 
  list 
  : 
  — 
  

  

  1. 
  Mastodonsaurus, 
  Jager. 
  

  

  1. 
  M. 
  giganteus, 
  Jager, 
  = 
  M. 
  Jcegeri, 
  Alberti. 
  

  

  2. 
  M. 
  pachygnathus, 
  Owen. 
  

  

  2. 
  Labtrinthodon, 
  Owen. 
  

   1. 
  L. 
  leptognaihus, 
  Owen. 
  

  

  3. 
  DlADETOGNATHUS, 
  Miall. 
  

  

  1. 
  D. 
  varvicensis, 
  Miall. 
  

  

  {Addendum, 
  May 
  1874.) 
  

  

  5 
  a. 
  Mastodonsaurus 
  ? 
  — 
  epiotic 
  and 
  parts 
  of 
  adjacent 
  bones. 
  Blake- 
  

   down 
  Hill. 
  PI. 
  XXYII. 
  figs. 
  4 
  A, 
  4 
  B. 
  

  

  This 
  fossil 
  comprises 
  the 
  epiotic 
  of 
  the 
  right 
  side, 
  nearly 
  all 
  the 
  

   supraoccipital, 
  and 
  portions 
  of 
  the 
  squamosal 
  and 
  parietal. 
  The 
  

   subcutaneous 
  sculpture 
  is 
  very 
  like 
  that 
  of 
  Mastodonsaurus 
  ; 
  but 
  the 
  

   * 
  Geol. 
  Trans. 
  2nd 
  series, 
  vol. 
  vi. 
  p. 
  543. 
  

  

  