﻿88 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  sauria, 
  renders 
  it 
  impossible 
  that 
  they 
  should 
  have 
  reached 
  the 
  ground, 
  in 
  progression, 
  if 
  

   the 
  posterior 
  were 
  at 
  all 
  extended, 
  and 
  suggests 
  that 
  these 
  reptiles 
  walked 
  erect. 
  That 
  

   this 
  was 
  the 
  case 
  is 
  demonstrable 
  from 
  the 
  materials 
  at 
  our 
  disposal, 
  I 
  am 
  inclined 
  to 
  

   believe. 
  

  

  The 
  ilium, 
  instead 
  of 
  having 
  a 
  vertical 
  position 
  as 
  in 
  reptiles, 
  is 
  longitudinal 
  as 
  in 
  

   birds. 
  That 
  is, 
  the 
  small 
  process 
  which, 
  in 
  Lacertilians 
  and 
  Crocodiles, 
  projects 
  in 
  advance 
  

   of 
  the 
  acetabulum, 
  is 
  largely 
  extended 
  and 
  developed, 
  while 
  the 
  lower 
  extremity 
  of 
  the 
  

   posterior, 
  or 
  principal 
  portion, 
  is 
  raised 
  anteriorly, 
  so 
  that 
  the 
  two 
  together 
  constitute 
  an 
  

   elongate 
  element, 
  embracing 
  not 
  only 
  the 
  two 
  posterior 
  or 
  original 
  sacral 
  vertebra?, 
  but 
  

   a 
  considerable 
  number 
  anterior 
  to 
  them. 
  The 
  effect 
  of 
  this 
  is 
  to 
  diminish 
  the 
  proportionate 
  

   number 
  of 
  lumbar 
  or 
  dorsal 
  vertebra?, 
  to 
  increase 
  the 
  length 
  of 
  the 
  consolidated 
  sacral 
  

   series, 
  and 
  to 
  throw 
  the 
  acetabulum, 
  and 
  consequently 
  the 
  femur 
  farther 
  anteriorly, 
  and 
  

   also 
  farther 
  upwards, 
  than 
  in 
  the 
  ordinary 
  reptiles. 
  All 
  these 
  features 
  are 
  characteristic 
  

   of 
  the 
  birds, 
  and 
  have 
  direct 
  reference 
  to 
  an 
  upright 
  position. 
  Thus 
  it 
  is 
  readily 
  per- 
  

   ceived 
  that 
  the 
  consolidation 
  of 
  the 
  sacrum, 
  is 
  related 
  to 
  the 
  need 
  of 
  a 
  greater 
  strength 
  of 
  

   support 
  at 
  a 
  single 
  point; 
  its 
  length, 
  and 
  that 
  of 
  the 
  ilium, 
  to 
  the 
  throwing 
  forwards 
  of 
  

   that 
  support 
  to 
  beneath 
  the 
  centre 
  of 
  gravity 
  of 
  the 
  animal's 
  body. 
  

  

  The 
  very 
  elevated 
  position 
  of 
  the 
  acetabulum, 
  and 
  consequently 
  of 
  the 
  usual 
  point 
  of 
  

   support 
  of 
  the 
  pubes, 
  renders 
  it 
  in 
  the 
  highest 
  degree 
  improbable 
  that 
  the 
  latter 
  bones 
  

   had 
  the 
  usual 
  direction 
  and 
  position 
  seen 
  in 
  the 
  reptiles. 
  That 
  is, 
  an 
  anterior 
  position 
  

   would 
  not 
  allow 
  of 
  space 
  for 
  the 
  enlarged 
  visceral 
  cavity 
  which 
  these 
  creatures 
  probably 
  

   possessed. 
  But 
  it 
  is 
  obvious 
  that 
  in 
  most 
  of 
  the 
  Dinosauria, 
  if 
  not 
  in 
  all, 
  the 
  pubes 
  were 
  

   not 
  supported 
  in 
  the 
  same 
  manner 
  as 
  in 
  most 
  Reptiles. 
  In 
  Hadrosaurus 
  and 
  Iguanodon 
  

   there 
  appears 
  to 
  have 
  been 
  absolutely 
  no 
  point 
  of 
  union 
  between 
  ilium 
  and 
  pubis, 
  and 
  in 
  

   Teratosaurus 
  and 
  Megalosaurus 
  that 
  union, 
  if 
  existing, 
  must 
  have 
  been 
  very 
  slight. 
  The 
  

   ischia 
  of 
  Stenopelix, 
  Hadrosaurus, 
  and 
  Iguanodon 
  furnish 
  the 
  substitute 
  for 
  this, 
  in 
  an 
  

   anteriorly 
  directed 
  process 
  for 
  the 
  support 
  of 
  the 
  pubis, 
  a 
  feature 
  otherwise 
  characteristic 
  

   of 
  the 
  Crocodilia 
  only, 
  among 
  reptiles. 
  

  

  I 
  conclude, 
  therefore, 
  that 
  the 
  pubes 
  were 
  not 
  directed 
  forwards 
  and 
  that 
  they 
  were 
  

   not 
  directed 
  backwards 
  either, 
  in 
  those 
  forms 
  at 
  least, 
  where 
  there 
  is 
  no 
  preacetabular 
  sup- 
  

   port 
  for 
  that 
  bone. 
  They 
  must 
  therefore 
  have 
  been 
  directed 
  downwards, 
  and 
  this 
  is 
  the 
  

   position 
  they 
  have 
  in 
  the 
  extreme 
  avine 
  form 
  Compsognathus. 
  

  

  Such 
  ischia 
  as 
  we 
  are 
  acquainted 
  with, 
  are 
  of 
  a 
  remarkably 
  elongate 
  form, 
  simulating 
  

   those 
  of 
  birds 
  rather 
  those 
  of 
  reptiles, 
  and 
  indicating 
  clearly 
  the 
  existence 
  of 
  a 
  great 
  pelvic 
  

   visceral 
  cavity. 
  

  

  From 
  these 
  considerations 
  as 
  to 
  the 
  extent 
  of 
  the 
  pelvic 
  elements 
  we 
  derive 
  further, 
  that 
  

   the 
  visceral 
  cavity 
  was 
  mainly 
  supported 
  by 
  them 
  and 
  that 
  it 
  was 
  transferred 
  so 
  as 
  to 
  be 
  

  

  