﻿212 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  face, 
  in 
  front 
  by 
  the 
  vomers, 
  behind 
  by 
  the 
  nares 
  and 
  palatine 
  bones. 
  They 
  terminate 
  in 
  

   a 
  narrow 
  process 
  behind, 
  whose 
  extremity 
  is 
  broken 
  in 
  the 
  specimen 
  at 
  my 
  disposal, 
  but 
  

   which 
  is 
  too 
  slight 
  to 
  have 
  supported 
  a 
  malar 
  arch, 
  unless 
  it 
  were 
  as 
  in 
  the 
  Dolphins. 
  

   Each 
  maxillary 
  bears 
  seventeen 
  sub-equal 
  teeth. 
  The 
  nostrils 
  are 
  linear 
  and 
  superior, 
  as 
  

   in 
  Mosasaurus, 
  and 
  if 
  separated 
  by 
  a 
  septum, 
  it 
  was 
  exceedingly 
  slender. 
  A 
  portion 
  of 
  it 
  

   has 
  been 
  preserved 
  ; 
  it 
  appears 
  to 
  be 
  composed 
  of 
  co-ossified 
  nasal 
  and 
  frontal 
  bones. 
  The 
  

   nares 
  extend 
  to 
  a 
  point 
  as 
  far 
  in 
  advance 
  of 
  the 
  anterior 
  margin 
  of 
  the 
  orbit, 
  as 
  the 
  latter 
  is 
  

   in 
  advance 
  of 
  the 
  posterior 
  margin 
  of 
  the 
  post-orbitals. 
  The 
  "prefrontals 
  are 
  largely 
  devel- 
  

   oped 
  and 
  margin 
  the 
  posterior 
  part 
  of 
  the 
  nares. 
  Their 
  posterior 
  exterior 
  margin 
  projects 
  

   strongly 
  in 
  the 
  plane 
  of 
  the 
  muzzle, 
  and 
  has 
  caused 
  the 
  orbit 
  to 
  be 
  horizontal, 
  and 
  the 
  

   range 
  of 
  vision 
  vertical, 
  as 
  in 
  some 
  aquatic 
  serpents. 
  ♦ 
  

  

  The 
  frontal 
  is 
  a 
  wedge-shaped 
  flat 
  bone. 
  The 
  post 
  frontals 
  are 
  large, 
  flat 
  and 
  promi- 
  

   nent, 
  and 
  project 
  beyond 
  the 
  process 
  they 
  send 
  posteriorly 
  to 
  join 
  the 
  squamosal. 
  Pos- 
  

   teriorly 
  it 
  embraces 
  a 
  broad 
  rectangular 
  process 
  of 
  the 
  parietal, 
  which 
  contains 
  near 
  its 
  

   front 
  suture, 
  the 
  parietal 
  fontanelle. 
  The 
  projection 
  is 
  considerably 
  wider 
  than 
  as 
  repre- 
  

   sented 
  by 
  Goldfuss 
  in 
  the 
  genus 
  Mosasaurus. 
  

  

  The 
  -parietal 
  has 
  two 
  broad 
  lateral 
  wings, 
  which 
  advance 
  on 
  the 
  frontal, 
  and 
  form 
  pos- 
  

   teriorly 
  the 
  broad 
  anterior 
  margin 
  of 
  the 
  temporal 
  fossa. 
  The 
  parietal 
  crests 
  are 
  separ- 
  

   ated 
  by 
  a 
  plane 
  which 
  is 
  narrowed 
  posteriorly. 
  Two 
  antero-superior 
  projections 
  of 
  the 
  

   supraoccipital 
  embrace 
  it 
  on 
  each 
  side 
  below 
  the 
  crest, 
  while 
  it 
  is 
  overlapped 
  just 
  below, 
  

   by 
  the 
  anterior 
  extremity 
  of 
  the 
  prootic 
  ; 
  this 
  does 
  not 
  extend 
  so 
  far 
  forwards 
  as 
  the 
  su- 
  

   praoccipital. 
  In 
  front 
  of, 
  and 
  below 
  this 
  point, 
  the 
  parietal 
  is 
  decurved, 
  and 
  forms 
  a 
  con- 
  

   siderable 
  part 
  of 
  the 
  lateral 
  wall 
  of 
  the 
  cranium 
  ; 
  though 
  with 
  but 
  moderate 
  antero-pos- 
  

   terior 
  extent. 
  The 
  plate, 
  as 
  preserved 
  on 
  one 
  side 
  of 
  the 
  specimen, 
  has 
  extended 
  to 
  the 
  

   body 
  of 
  the 
  sphenoid, 
  where 
  extensive 
  sutural 
  surface 
  has 
  received 
  it. 
  I 
  can 
  find 
  no 
  suture 
  

   crossing 
  it, 
  and 
  it 
  is 
  apparently 
  all 
  alisphenoid 
  or 
  all 
  parietal. 
  I 
  incline 
  to 
  the 
  former 
  

   view, 
  for 
  where 
  it 
  is 
  separated 
  at 
  its 
  superior 
  base 
  from 
  the 
  parietal, 
  the 
  appearance 
  is 
  

   quite 
  as 
  similar 
  to 
  suture 
  as 
  fracture. 
  A 
  part 
  of 
  the 
  parietal 
  is, 
  however, 
  undoubtedly 
  de- 
  

   curved 
  in 
  front 
  of 
  it. 
  The 
  structure 
  is 
  quite 
  as 
  Crocodilian 
  as 
  Ophidian 
  in 
  this 
  point. 
  

  

  The 
  anterior 
  ala 
  of 
  the 
  prootic 
  overlaps 
  this 
  alisphenoid 
  largely. 
  Its 
  posterior 
  lamina 
  

   does 
  not 
  quite 
  meet 
  the 
  expansion 
  of 
  the 
  exoccipital 
  on 
  the 
  upper 
  face 
  of 
  the 
  suspenso- 
  

   rium, 
  as 
  it 
  does 
  in 
  Mosasaurus. 
  Interiorly 
  it 
  is 
  contact 
  with 
  outer 
  and 
  posterior 
  base 
  of 
  

   the 
  sphenoid. 
  

  

  The 
  supraoccipital 
  is 
  somewhat 
  crushed; 
  it 
  is 
  slightly 
  roof-shaped, 
  but 
  not 
  so 
  much 
  so 
  

   as 
  in 
  M. 
  missuriensis, 
  nor 
  so 
  much 
  below 
  the 
  plane 
  of 
  the 
  parietals 
  as 
  in 
  that 
  genus. 
  The 
  

   posterior 
  extremity 
  of 
  the 
  parietal 
  appears 
  • 
  to 
  rest 
  upon 
  it 
  without 
  sending 
  arches 
  to 
  the 
  

   opisthotic. 
  

  

  