﻿FEOM 
  THE 
  KEUPEE 
  SANDSTONE 
  OP 
  WAEWICK. 
  419 
  

  

  words, 
  the 
  proportions 
  as 
  well 
  as 
  the 
  dimensions 
  differ. 
  The 
  present 
  

   fossil 
  will 
  probably 
  prove 
  to 
  be 
  specifically 
  identical 
  with 
  some 
  of 
  

   the 
  remains 
  named 
  Labyrinihodon 
  (Mastodonsaurus) 
  pachygnaihus 
  

   by 
  Prof. 
  Owen; 
  but 
  that 
  species 
  is 
  as 
  yet 
  inadequately 
  defined. 
  

  

  Measurements 
  : 
  — 
  in. 
  

  

  Width 
  of 
  interorbital 
  space 
  in 
  the 
  narrowest 
  part 
  .... 
  1-|- 
  

  

  Length 
  of 
  orbit 
  (restored), 
  about 
  2| 
  

  

  Greatest 
  thickness 
  5 
  

  

  Measurements 
  of 
  M. 
  giganteus 
  (for 
  comparison) 
  : 
  — 
  

  

  "Width 
  of 
  interorbital 
  space 
  in 
  the 
  narrowest 
  part 
  .... 
  2§ 
  

  

  Length 
  of 
  orbit, 
  about 
  6 
  

  

  2. 
  Mastodonsatjeus 
  pachtgnathtts, 
  Ow. 
  — 
  part 
  of 
  postero-external 
  

  

  orbital 
  margin. 
  Coton 
  End, 
  1872. 
  PI. 
  XXVI. 
  fig. 
  1 
  B. 
  

  

  The 
  sculpture, 
  as 
  -well 
  as 
  the 
  proportions, 
  of 
  this 
  fragment 
  connect 
  

   it 
  with 
  Mastodonsaurus. 
  I 
  am 
  not 
  quite 
  sure 
  of 
  its 
  position 
  in 
  the 
  

   skull. 
  The 
  concave 
  and 
  bevelled 
  margin, 
  ab, 
  must 
  have 
  bounded 
  

   the 
  orbit 
  ; 
  yet 
  it 
  cannot 
  belong 
  to 
  the 
  anterior 
  or 
  prefrontal 
  part 
  of 
  

   the 
  orbit, 
  as 
  the 
  underside 
  shows 
  no 
  bevelling. 
  We 
  may 
  pretty 
  

   confidently 
  assign 
  it 
  to 
  the 
  outer 
  wall, 
  in 
  which 
  case 
  the 
  suture, 
  c, 
  

   represents 
  the 
  junction 
  of 
  the 
  postorbital 
  with 
  the 
  jugal, 
  and 
  dd' 
  

   the 
  malar 
  mucous 
  canal 
  (Backenfurche 
  of 
  Burmeister). 
  The 
  bone 
  

   is 
  stouter 
  than 
  the 
  preceding 
  fragment, 
  and 
  the 
  sculpture 
  is 
  deeper. 
  

  

  Measurements 
  : 
  — 
  in. 
  

  

  Greatest 
  thickness 
  (near 
  the 
  orbital 
  edge) 
  -j^L 
  

  

  Width 
  of 
  maxillary 
  groove 
  | 
  

  

  3. 
  Mastodonsattetts 
  PACHTGNATHus, 
  Owen 
  — 
  postero-external 
  angle 
  

  

  of 
  skull 
  (left 
  side). 
  PI. 
  XXVII. 
  figs. 
  1 
  A, 
  1 
  B, 
  and 
  woodcut 
  fig. 
  1 
  . 
  

  

  This 
  fragment 
  comprises 
  part 
  of 
  the 
  roof 
  of 
  the 
  temporal 
  fossa 
  and 
  

   the 
  greater 
  part 
  of 
  the 
  articulation 
  for 
  the 
  mandible. 
  These 
  portions 
  

   of 
  the 
  skull 
  are 
  respectively 
  represented 
  by 
  a 
  strong 
  process 
  directed 
  

   horizontally 
  inwards 
  from 
  the 
  postero-inferior 
  angle, 
  and 
  by 
  an 
  

   expanded 
  plate. 
  The 
  plate 
  is 
  gently 
  convex 
  above, 
  and 
  shows 
  the 
  

   usual 
  sculpture 
  of 
  a 
  subcutaneous 
  cranial 
  surface 
  ; 
  the 
  lower 
  side 
  is 
  

   nearly 
  smooth. 
  The 
  greatest 
  thickness 
  is 
  at 
  the 
  postero-inferior 
  

   angle. 
  The 
  inferior 
  border 
  is 
  thinned 
  off 
  to 
  an 
  edge 
  ; 
  it 
  is 
  somewhat 
  

   undulated, 
  descending 
  gradually 
  from 
  behind 
  so 
  as 
  to 
  overlap 
  the 
  

   outer 
  surface 
  of 
  the 
  mandible, 
  and 
  then 
  gradually 
  rising 
  in 
  front. 
  

   Behind, 
  where 
  it 
  is 
  rather 
  more 
  depressed 
  than 
  further 
  forwards, 
  the 
  

   plate 
  makes, 
  with 
  a 
  horizontal 
  transverse 
  line, 
  an 
  angle 
  of 
  about 
  60°, 
  

   measured 
  as 
  rectilinear. 
  It 
  is 
  mainly 
  formed 
  by 
  the 
  quadrato-jugal 
  

   (Q 
  J.) 
  ; 
  but 
  a 
  portion 
  of 
  the 
  supratemporal 
  (S 
  T) 
  remains 
  attached 
  to 
  

   the 
  postero-superior 
  angle, 
  and 
  a 
  fragment 
  of 
  the 
  jugal 
  is 
  present 
  in 
  

   front. 
  I 
  am 
  not 
  sure 
  whether 
  the 
  fossil 
  includes 
  any 
  part 
  of 
  the 
  

   maxilla. 
  The 
  supratemporal 
  and 
  jugal 
  are 
  coarticulated 
  by 
  means 
  of 
  

   extended 
  sutures, 
  which 
  overlap 
  considerably 
  the 
  quadrato-jugal. 
  On 
  

   the 
  under 
  surface 
  numerous 
  vascular 
  foramina 
  appear, 
  especially 
  in 
  

   the 
  angle 
  between 
  the 
  articular 
  process 
  and 
  the 
  quadrato-jugal 
  plate. 
  

  

  