﻿ISCHIUM 
  OF 
  OKNITHOPBIS 
  EUCAMEEOTT7S. 
  375 
  

  

  of 
  Ceteosaurus 
  ooconiensis 
  and 
  Atlantosaurus, 
  Omitliopsis 
  departs 
  from 
  

   the 
  original 
  Dinosaurian 
  scheme 
  as 
  typified 
  by 
  Iguanodon, 
  and 
  takes 
  

   the 
  direction 
  of 
  Lacertilia, 
  in 
  which 
  the 
  postpubic 
  extension, 
  so 
  de- 
  

   veloped 
  in 
  the 
  os 
  pubis 
  of 
  Iguanodon, 
  is 
  absent, 
  and 
  there 
  is 
  no 
  os- 
  

   teally 
  closed 
  obturator 
  foramen. 
  It 
  differs, 
  however, 
  from 
  the 
  Lacer- 
  

   tilian 
  haunch-bone 
  in 
  the 
  absence 
  of 
  ischial 
  symphysis, 
  unless 
  I 
  have 
  

   been 
  deceived 
  on 
  this 
  point; 
  and 
  also 
  from 
  the 
  Crocodilian 
  form 
  

   notably 
  in 
  the 
  inclusion 
  of 
  the 
  os 
  pubis 
  in 
  the 
  acetabular 
  circle. 
  

  

  These 
  and 
  other 
  associated 
  departures 
  from 
  the 
  typical 
  Dino- 
  

   saurian 
  patterns 
  have 
  led 
  Prof. 
  0. 
  C. 
  Marsh 
  to 
  place 
  Atlantosaurus 
  

   with 
  other 
  of 
  the 
  newly 
  discovered 
  Colorado 
  Sauria 
  in 
  a 
  special 
  sub- 
  

   order 
  of 
  Dinosauria, 
  the 
  Sauropoda, 
  in 
  which 
  Omitliopsis 
  clearly 
  

   finds 
  its 
  proper 
  place. 
  

  

  Postscript. 
  

  

  For 
  reasons 
  stated 
  in 
  a 
  former 
  paper 
  I 
  adhere 
  to 
  the 
  prior 
  generic 
  

   name 
  Omitliopsis, 
  given 
  by 
  Prof. 
  H. 
  G. 
  Seeley; 
  and 
  since 
  this 
  genus 
  

   was 
  founded 
  on 
  two 
  vertebral 
  centra 
  (Nos. 
  2239, 
  28362, 
  Brit. 
  Mus. 
  

   Catal.) 
  which 
  there 
  are 
  grounds 
  for 
  referring 
  to 
  distinct 
  species, 
  I 
  

   adopt 
  Eucamerotus 
  as 
  the 
  specific 
  name 
  of 
  the 
  subject 
  of 
  this 
  note, 
  

   and 
  reserve 
  the 
  specific 
  name 
  Hulkei, 
  given 
  by 
  Prof. 
  Seeley, 
  for 
  

   the 
  Saurian 
  indicated 
  by 
  the 
  fossil 
  No. 
  2239. 
  The 
  annexed 
  list 
  

   contains 
  all 
  the 
  references 
  I 
  can 
  find 
  to 
  papers 
  giving 
  descriptions 
  

   of 
  fossils 
  referable 
  to 
  this 
  genus. 
  

  

  List 
  of 
  Papers 
  on 
  Ornithopsis. 
  

  

  1. 
  Mantell, 
  G. 
  A. 
  Fossils 
  of 
  the 
  British 
  Museum, 
  p. 
  250* 
  8vo, 
  

  

  London, 
  1851. 
  

  

  (Notice 
  of 
  no. 
  2239 
  fossil 
  in 
  Brit. 
  Mus., 
  regarded 
  by 
  author 
  

   as 
  tympanic 
  of 
  Iguanodon.) 
  

  

  2. 
  Mantell, 
  G. 
  A. 
  Geologv 
  of 
  S.E. 
  of 
  England, 
  pp. 
  305-306, 
  pi. 
  ii. 
  

  

  fig. 
  5. 
  

  

  (Notice 
  of 
  same 
  fossil,) 
  

  

  3. 
  Owen, 
  R. 
  Report 
  on 
  British 
  Fossil 
  Eeptilia 
  in 
  Reports 
  of 
  Brit. 
  

  

  Assoc, 
  vol. 
  for 
  1841, 
  p. 
  124. 
  

  

  4. 
  Owen, 
  R. 
  Monograph 
  of 
  Foss. 
  Rept. 
  of 
  Wealden 
  Formation 
  in 
  

  

  Pal. 
  Soc. 
  vol. 
  for 
  1854, 
  p. 
  18, 
  pi. 
  x. 
  

  

  (3, 
  4. 
  Notice 
  of 
  same 
  fossil. 
  The 
  author 
  accepts 
  MantelFs 
  

   determination, 
  but 
  suggests 
  it 
  may 
  have 
  belonged 
  to 
  Ceteosaurus 
  

   or 
  Streptospondylus.) 
  

  

  5. 
  Seeley, 
  H. 
  G. 
  On 
  Ornithopsis, 
  a 
  Gigantic 
  Animal 
  of 
  the 
  Ptero- 
  

  

  dactyle 
  kind 
  from 
  the 
  Wealden. 
  Annals 
  & 
  Mag. 
  of 
  Nat. 
  Hist, 
  

   ser. 
  4, 
  vol. 
  v. 
  p. 
  279 
  (1870). 
  

  

  (A 
  paper 
  on 
  the 
  fossil 
  no. 
  2239, 
  recognized 
  by 
  the 
  author 
  as 
  

   a 
  vertebral 
  centrum, 
  and 
  on 
  another 
  centrum, 
  no. 
  28362 
  in 
  

   Brit. 
  Mus. 
  ; 
  read 
  bofore 
  Camb. 
  Phil. 
  Soc. 
  22 
  Nov. 
  1869.) 
  

  

  6. 
  Hulke, 
  J. 
  W. 
  Note 
  on 
  a 
  new 
  and 
  undescribed 
  Wealden 
  Vertebra. 
  

  

  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxvi. 
  p. 
  318 
  (1870). 
  

  

  (Description 
  of 
  the 
  neural 
  arch 
  of 
  a 
  thoracic 
  vertebra 
  under 
  

   . 
  the 
  name 
  of 
  Eucamerotus.) 
  

  

  2c2 
  

  

  