﻿46 
  MR. 
  E. 
  LYDEEKER 
  OX 
  THE 
  EEMAIXS 
  AXD 
  AEEIXITIES 
  

  

  the 
  extreme 
  stoutness 
  of 
  the 
  shaft 
  and 
  the 
  total 
  absence 
  of 
  a 
  dis- 
  

   tinct 
  distal 
  intercondylar 
  groove 
  on 
  the 
  anterior 
  aspect. 
  The 
  

   name 
  Cryptosaurus 
  is, 
  however, 
  preoccupied 
  by 
  Geoffroy, 
  and 
  this 
  

   form, 
  assuming 
  it 
  to 
  be 
  distinct 
  from 
  other 
  types, 
  accordingly 
  

   requires 
  a 
  new 
  generic 
  name, 
  for 
  which 
  I 
  would 
  propose 
  Crypto- 
  

   draeo. 
  

  

  During 
  a 
  visit 
  to 
  the 
  collection 
  of 
  Reptilian 
  remains 
  from 
  the 
  

   Oxford 
  Clay 
  near 
  Peterborough 
  in 
  the 
  collection 
  of 
  Mr. 
  A. 
  N. 
  Leeds, 
  

   of 
  Eyebury, 
  I 
  was 
  shown 
  the 
  left 
  femur 
  of 
  an 
  Iguanodont 
  Dinosaur, 
  

   which 
  I 
  thought 
  might 
  perhaps 
  prove 
  identical 
  with 
  Cryptodraco. 
  

   This 
  specimen 
  the 
  owner 
  has 
  kindly 
  permitted 
  me 
  to 
  bring 
  to 
  the 
  

   notice 
  of 
  the 
  Society. 
  The 
  middle 
  portion 
  of 
  the 
  shaft 
  has 
  been 
  

   considerably 
  crushed 
  and 
  broken, 
  but 
  both 
  extremities 
  are 
  entire. 
  

   The 
  shaft 
  agrees 
  with 
  that 
  of 
  the 
  femur 
  of 
  Hysilophodon 
  and 
  of 
  the 
  

   North- 
  American 
  Camptosaurus 
  (Camptonotus), 
  and 
  differs 
  from 
  that 
  

   of 
  Iguanodon 
  in 
  its 
  markedly 
  forward 
  arcuation. 
  The 
  inner 
  tro- 
  

   chanter 
  has 
  lost 
  its 
  free 
  extremity, 
  but 
  the 
  basal 
  portion 
  shows 
  that 
  

   it 
  is 
  of 
  the 
  " 
  pendant 
  " 
  type 
  characteristic 
  of 
  the 
  two 
  former 
  genera, 
  

   and 
  not 
  of 
  the 
  " 
  crested 
  " 
  type 
  found 
  in 
  Iguanodon*. 
  The 
  anterior 
  

   intercondylar 
  groove 
  is 
  slightly 
  less 
  developed 
  in 
  this 
  specimen 
  than 
  

   in 
  either 
  of 
  the 
  Wealden 
  genera, 
  but 
  it 
  is 
  still 
  present. 
  Compared 
  

   with 
  the 
  type 
  of 
  Cryptodraco 
  this 
  bone 
  differs 
  very 
  widely, 
  so 
  that 
  

   there 
  can 
  be 
  no 
  doubt 
  as 
  to 
  both 
  its 
  specific 
  and 
  generic 
  dis- 
  

   tinctness. 
  Thus 
  it 
  is 
  much 
  more 
  slender 
  ; 
  its 
  shaft 
  more 
  curved 
  ; 
  

   the 
  head 
  smaller 
  instead 
  of 
  larger 
  than 
  the 
  great 
  trochanter; 
  

   the 
  lesser 
  trochanter 
  thinner 
  and 
  taller 
  ; 
  and 
  the 
  distal 
  end 
  less 
  

   flattened, 
  and 
  with 
  a 
  distinct 
  intercondylar 
  groove. 
  The 
  inner 
  

   trochanter 
  is 
  wanting 
  in 
  the 
  larger 
  bone. 
  

  

  Leaving, 
  then, 
  the 
  femur 
  of 
  Cryptodraco 
  on 
  one 
  side, 
  as 
  indicating 
  

   a 
  totally 
  distinct 
  form, 
  we 
  may 
  look 
  around 
  for 
  other 
  described 
  

   Iguanodonts 
  with 
  which 
  to 
  compare 
  our 
  specimen. 
  

  

  The 
  close 
  relationship 
  existing 
  between 
  the 
  Reptiles 
  of 
  the 
  Oxford 
  

   and 
  Kimeridge 
  Clays 
  (those 
  of 
  the 
  former 
  being 
  frequently 
  some- 
  

   what 
  smaller 
  than 
  their 
  allies 
  of 
  the 
  latter) 
  suggests 
  that 
  the 
  present 
  

   form 
  may 
  be 
  closely 
  allied 
  to 
  Iguanodon 
  Prestwichii 
  of 
  the 
  Kimer- 
  

   idgian, 
  which 
  was 
  described 
  some 
  years 
  ago 
  by 
  Mr. 
  Hulke 
  in 
  

   our 
  ' 
  Journal,' 
  and 
  which 
  Professor 
  Seeley 
  last 
  year 
  proposed 
  to 
  

   separate 
  generically 
  under 
  the 
  name 
  of 
  Cumnoria. 
  The 
  entire 
  femur 
  

   of 
  that 
  form 
  is 
  unfortunately 
  unknown, 
  but 
  it 
  could 
  evidently 
  have 
  

   been 
  only 
  slightly 
  larger 
  than 
  the 
  present 
  specimen, 
  with 
  which 
  

   (as 
  I 
  have 
  satisfied 
  myself 
  by 
  personal 
  examination) 
  the 
  terminal 
  

   extremities 
  agree 
  very 
  closely. 
  Evidence 
  of 
  affinity 
  between 
  that 
  

   species 
  and 
  Camptosaurus 
  is 
  shown 
  by 
  the 
  angulated 
  and 
  flattened 
  

   haemal 
  surface 
  of 
  the 
  sacral 
  vertebra?, 
  and 
  by 
  the 
  absence 
  of 
  anchy- 
  

   losis 
  between 
  these 
  centra. 
  Having, 
  therefore, 
  two 
  Iguanodonts 
  

   from 
  contiguous 
  deposits, 
  both 
  of 
  which 
  show 
  marked 
  signs 
  of 
  

   affinity 
  with 
  Camptosaurus, 
  the 
  presumption 
  becomes 
  very 
  strong 
  

   indeed 
  that 
  they 
  are 
  closely 
  allied. 
  There 
  is, 
  indeed, 
  no 
  decisive 
  

  

  * 
  Attention 
  is 
  directed 
  to 
  these 
  two 
  types 
  by 
  M. 
  L. 
  Dollo 
  in 
  an 
  interesting 
  

   article 
  published 
  in 
  the 
  ; 
  Bull. 
  Sci. 
  France 
  et 
  Belgique,' 
  1868. 
  pp. 
  215-224. 
  

  

  