﻿224 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  on 
  any 
  of 
  the 
  teeth. 
  The 
  apex 
  curves 
  gently 
  inwards. 
  From 
  the 
  above, 
  the 
  greater 
  compression 
  of 
  the 
  posterior 
  teeth 
  

   may 
  be 
  inferred. 
  

  

  The 
  pterygoid 
  teeth 
  present 
  no 
  cutting 
  angles, 
  and 
  are 
  gently 
  curved 
  backwards. 
  Like 
  the 
  maxillaries, 
  the 
  an- 
  

   terior 
  mandibular 
  teeth 
  have 
  no 
  posterior 
  edged 
  angle, 
  but 
  they 
  have 
  one 
  on 
  the 
  posterior 
  part 
  of 
  the 
  outer 
  side, 
  di- 
  

   viding 
  the 
  crown 
  into 
  two 
  very 
  unequal 
  faces, 
  the 
  inner 
  being 
  much 
  the 
  larger. 
  This 
  ridge 
  becomes 
  more 
  posterior 
  

   in 
  the 
  hinder 
  teeth, 
  but 
  the 
  outer 
  facet 
  is 
  never 
  larger 
  than 
  the 
  inner. 
  The 
  crown 
  is 
  faintly 
  ribbed, 
  but 
  not 
  so 
  as 
  to 
  

   be 
  facetted, 
  as 
  in 
  Holcodus 
  and 
  Mosasaurus. 
  Number 
  of 
  teeth 
  on 
  each 
  side: 
  premax., 
  2; 
  max., 
  eleven 
  functional, 
  and 
  

   alveola? 
  in 
  intervals 
  for 
  six 
  more; 
  mandibulars, 
  fifteen, 
  with 
  alveolae 
  for 
  three 
  others. 
  

  

  The 
  usual 
  vasculo-neural 
  foramina 
  occur 
  along 
  the 
  faces 
  of 
  the 
  maxillary 
  and 
  dentary 
  bones. 
  The 
  series 
  of 
  the 
  

   first 
  commences 
  by 
  two 
  small 
  ones, 
  one 
  above 
  the 
  other, 
  near 
  its 
  extremity; 
  this 
  is 
  followed 
  by 
  a 
  close 
  series, 
  there 
  

   being 
  three 
  opposite 
  two 
  adjacent 
  alveoli. 
  They 
  are 
  soon 
  more 
  widely 
  spaced, 
  and 
  number 
  sixteen 
  altogether. 
  There 
  

   are 
  eleven 
  on 
  the 
  dentary 
  bone, 
  quite 
  widely 
  spaced 
  behind; 
  the 
  anterior 
  small. 
  

  

  The 
  cranial 
  bones 
  are 
  all 
  minutely 
  striate, 
  the 
  upper 
  surfaces 
  of 
  the 
  parietal 
  and 
  occipital 
  most 
  strongly. 
  The 
  cor- 
  

   onoid 
  process 
  is 
  very 
  rugose 
  on 
  the 
  inner 
  aspect; 
  as 
  are 
  the 
  posterior 
  margins 
  of 
  the 
  angular, 
  up 
  to 
  the 
  terminal 
  line, 
  

   where 
  would 
  appear 
  to 
  have 
  been 
  a 
  band 
  of 
  cartilage 
  similar 
  to 
  that 
  at 
  the 
  articulation 
  of 
  the 
  ribs, 
  or 
  like 
  the 
  ends 
  of 
  

   the 
  caudal 
  neural 
  spines. 
  The 
  sutural 
  margins 
  of 
  the 
  angular 
  is 
  marked 
  by 
  delicate 
  radii. 
  The 
  external 
  surfaces 
  of 
  

   the 
  mandibular 
  bones 
  ai*e 
  minutely 
  striate, 
  like 
  the 
  bones 
  of 
  many 
  fishes. 
  

  

  The 
  proximal 
  part 
  of 
  the 
  internal 
  lamina 
  of 
  the 
  splenial 
  is 
  concave. 
  It 
  does 
  not 
  extend 
  to 
  the 
  end 
  of 
  the 
  ramus, 
  

   so 
  that 
  the 
  meckellian 
  groove 
  is 
  open 
  for 
  one-fourth 
  the 
  length 
  of 
  the 
  latter. 
  The 
  outer 
  face 
  of 
  the 
  ramus 
  is 
  regularly 
  

   convex. 
  The 
  splenial 
  disappears 
  from 
  view 
  at 
  a 
  point 
  opposite 
  the 
  fourth 
  tooth 
  from 
  behind. 
  The 
  inferior 
  ridge 
  of 
  

   the 
  mandible 
  is 
  straight 
  to 
  near 
  the 
  splenial 
  articulation, 
  where 
  it 
  is 
  directed 
  slightly 
  outwards. 
  On 
  the 
  proximal 
  

   part 
  of 
  the 
  mandible, 
  it 
  is 
  gently 
  convex 
  inwards 
  to 
  nearly 
  opposite 
  the 
  anterior 
  part 
  of 
  the 
  quadrate 
  cotylus, 
  where 
  

   it 
  is 
  convex 
  outwards; 
  the 
  plane 
  of 
  the 
  angle 
  is 
  then 
  directed 
  slightly 
  inwards, 
  and 
  is 
  very 
  rugose 
  below. 
  

  

  When 
  in 
  position, 
  the 
  plane 
  of 
  the 
  proximal 
  part 
  of 
  the 
  ramus 
  is 
  more 
  horizontal 
  than 
  that 
  of 
  the 
  distal. 
  From 
  the 
  

   splenial 
  joint 
  the 
  inferior 
  margin 
  becomes 
  more 
  horizontal, 
  until 
  the 
  broad 
  angle 
  is 
  nearly 
  transverse, 
  and 
  with 
  a 
  slight 
  

   inward 
  curve. 
  What 
  appears 
  when 
  examined 
  separately 
  to 
  be 
  the 
  external 
  face, 
  becomes 
  largely 
  inferior, 
  making 
  an 
  

   angle 
  of 
  45° 
  with 
  the 
  horizontal. 
  

  

  The 
  fossae 
  are 
  strongly 
  marked. 
  The 
  outer 
  edge 
  of 
  the 
  coronoid 
  rolls 
  back, 
  and 
  the 
  upper 
  edge 
  of 
  the 
  articular 
  

   forms 
  a 
  ridge, 
  enclosing 
  the 
  internal 
  fossa. 
  The 
  quadrate 
  cotylus 
  is 
  sub-longitudinal, 
  inclining 
  inwards 
  and 
  forwards, 
  

   and 
  with 
  a 
  high 
  anterior 
  margin. 
  

  

  Measurements. 
  

   Length 
  from 
  end 
  muzzle 
  to 
  occip. 
  condyle, 
  

   " 
  " 
  " 
  " 
  parietal 
  fontanelle, 
  

  

  " 
  " 
  " 
  " 
  poster, 
  extrem. 
  nares, 
  

  

  " 
  " 
  " 
  " 
  end 
  maxillary, 
  

  

  " 
  " 
  " 
  " 
  " 
  malar 
  process 
  do., 
  

  

  " 
  " 
  " 
  " 
  pre-frontal 
  angle, 
  

  

  " 
  " 
  " 
  " 
  post-frontal 
  " 
  

  

  • 
  " 
  (median) 
  temporal 
  fossa 
  (antero-posterior), 
  

   Width 
  at 
  anterior 
  extrem. 
  maxillaries, 
  

   " 
  " 
  pre-frontals, 
  

   " 
  " 
  post-frontals, 
  

  

  " 
  between 
  poster, 
  extrem. 
  squamosals, 
  

   " 
  " 
  anter. 
  extrem. 
  prootics, 
  

  

  " 
  " 
  parietal 
  crests 
  behind, 
  

  

  " 
  " 
  " 
  " 
  at 
  parietal 
  fontanelle, 
  

  

  " 
  of 
  suspensorium, 
  

   " 
  " 
  septum 
  narium 
  at 
  poster, 
  extram., 
  

   Length 
  suspensorium 
  (without 
  squamosal), 
  

  

  In, 
  

  

  Lin. 
  

  

  14 
  

  

  4 
  

  

  11 
  

  

  3 
  

  

  6 
  

  

  6 
  

  

  

  11 
  

  

  9 
  

  

  

  

  8 
  

  

  11 
  

  

  11 
  

  

  9.5 
  

  

  1 
  

  

  9 
  

  

  

  9 
  

  

  4 
  

  

  1 
  

  

  5 
  

  

  

  5 
  

  

  1.2 
  

  

  

  16.3 
  

  

  

  5.5 
  

  

  

  14.3 
  

  

  

  6.7 
  

  

  

  7.2 
  

  

  

  19 
  

  

  