﻿176 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  with 
  unsatisfactory 
  results. 
  While 
  Faujas 
  believed 
  it 
  to 
  be 
  a 
  crocodile, 
  Camper 
  and 
  Cuvier 
  

   regarded 
  it 
  as 
  a 
  lacertian, 
  and 
  placed 
  it 
  near 
  the 
  Monitor. 
  In 
  the 
  latter 
  relation 
  it 
  has 
  

   been 
  allowed 
  to 
  remain 
  by 
  Goldfuss 
  and 
  Owen, 
  who 
  have 
  since 
  written 
  upon 
  it, 
  and 
  so 
  it 
  

   continues 
  to 
  be 
  regarded 
  by 
  all 
  palaeontologists 
  of 
  the 
  present 
  day, 
  who 
  have 
  expressed 
  an 
  

   opinion 
  on 
  the 
  subject. 
  

  

  I 
  have, 
  however, 
  been 
  able 
  to 
  demonstrate, 
  by 
  the 
  light 
  of 
  new 
  material 
  recently 
  dis- 
  

   covered, 
  that 
  the 
  Mosasauridae 
  and 
  Clidasticlae 
  constitute 
  a 
  peculiar 
  order 
  of 
  Reptiles, 
  

   which 
  possesses 
  a 
  combination 
  of 
  the 
  characters 
  of 
  Serpents, 
  with 
  those 
  of 
  Lacertilia, 
  and 
  

   some 
  others 
  of 
  the 
  Sauropterygia. 
  The 
  reason 
  why, 
  as 
  I 
  conceive, 
  this 
  genus 
  and 
  its 
  allies 
  

   have 
  been 
  so 
  little 
  understood, 
  has 
  been 
  a 
  lack 
  of 
  analysis 
  of 
  the 
  structure 
  of 
  portions 
  of 
  

   the 
  cranium 
  little 
  known, 
  as 
  well 
  as 
  of 
  portions 
  better 
  known, 
  and 
  the 
  lack 
  of 
  certainty 
  

   as 
  to 
  the 
  structure 
  of 
  the 
  limbs. 
  

  

  The 
  characters 
  of 
  the 
  order 
  are 
  as 
  follows 
  : 
  

  

  First. 
  The 
  teeth 
  have 
  no 
  fangs. 
  

  

  Second. 
  The 
  opisthotic 
  bone 
  projects 
  free 
  from 
  the 
  cranium, 
  and 
  is 
  the 
  suspensorium 
  

   of 
  the 
  os 
  quadratum. 
  

  

  Third. 
  There 
  is 
  no 
  columella. 
  

  

  Fourth. 
  There 
  is 
  no 
  symphysis 
  mandibuli. 
  

  

  Fifth. 
  The 
  parietal 
  is 
  decurved 
  posteriorly, 
  and 
  extends 
  to 
  the 
  \ 
  sphenoid, 
  forming 
  the 
  

   cranial 
  wall 
  in 
  front 
  of 
  the 
  prootic. 
  

  

  Sixth. 
  The 
  subarticular 
  and 
  splenial 
  elements 
  of 
  the 
  mandible 
  are 
  connected 
  by 
  artic- 
  

   ular 
  faces. 
  » 
  

  

  Seventh. 
  The 
  vertebrae 
  are 
  very 
  numerous, 
  much 
  exceeding 
  one 
  hundred, 
  and 
  frequently 
  

   present 
  the 
  zygosphen 
  articulation. 
  

  

  Eighth. 
  The 
  abdominal 
  cavity 
  is 
  long 
  and 
  is 
  surrounded 
  by 
  many 
  short 
  curved 
  ribs, 
  

   which 
  have 
  simple 
  heads 
  and 
  a 
  free 
  antero-posterior 
  movement 
  on 
  vertical 
  articulating 
  

   surfaces, 
  and 
  which 
  commence 
  close 
  behind 
  the 
  axis 
  vertebra. 
  

  

  Ninth. 
  The 
  pterygoids 
  are 
  elongate 
  and 
  bear 
  numerous 
  teeth, 
  and 
  in 
  one 
  type 
  are 
  free 
  

   except 
  at 
  the 
  extremities. 
  

  

  Tenth. 
  The 
  brain 
  case 
  is 
  not 
  fully 
  ossified 
  anteriorlv. 
  

  

  Eleventh. 
  Scapular 
  and 
  coracoid 
  elements 
  are 
  present. 
  

  

  Twelfth. 
  The 
  caudal 
  vertebrae 
  are 
  furnished 
  with 
  chevron 
  bones. 
  

  

  Thirteenth. 
  The 
  squamosal 
  bone 
  is 
  present. 
  

  

  Fourteenth. 
  The 
  angular 
  bone 
  is 
  distinct. 
  

  

  Fifteenth. 
  The 
  os 
  quadratum 
  is 
  moveably 
  articulated 
  to 
  the 
  opisthotic. 
  

  

  Sixteenth. 
  The 
  os 
  quadratum 
  embraces 
  and 
  encloses 
  the 
  meatus 
  auditorius 
  externus. 
  

  

  Seventeenth. 
  The 
  opisthotic 
  is 
  supported 
  by 
  a 
  pedestal 
  projecting 
  from 
  the 
  cranial 
  

  

  