﻿Onntliosaurian 
  Genus 
  Ornitlioclieinis. 
  537 
  

  

  discernecl"^, 
  Seeley's 
  first 
  decision 
  is 
  tlie 
  correct 
  one, 
  wliich 
  

   coincides 
  with 
  Owen's. 
  Moreover, 
  if 
  this 
  be 
  a 
  lower 
  jaw, 
  

   and 
  the 
  usnal 
  proportion 
  of 
  a 
  lower 
  to 
  an 
  upper 
  obtain, 
  the 
  

   depth 
  of 
  the 
  tip 
  of 
  the 
  muzzle 
  would 
  be 
  so 
  excessive 
  that 
  the 
  

   supposition 
  becomes 
  highly 
  improbable. 
  

  

  Group 
  No. 
  5. 
  

  

  Beak 
  lanceolate, 
  compressed, 
  pointed, 
  edentulous. 
  

   Example 
  : 
  — 
  

  

  Ornithostoma. 
  R. 
  Owen, 
  Rep. 
  Cret. 
  Form. 
  (1850), 
  Sappl. 
  i. 
  pi. 
  iv. 
  

   iigs. 
  4 
  & 
  5 
  ; 
  and 
  II. 
  G. 
  Seeley, 
  Ann. 
  k 
  Mag. 
  Nat. 
  Hist. 
  (4) 
  vol. 
  vii. 
  

   p: 
  35, 
  footnote 
  (1871), 
  and 
  elsewhere. 
  

  

  It 
  will 
  be 
  useful 
  now 
  to 
  review 
  the 
  specimens 
  other 
  than 
  

   in 
  the 
  Sedgwick 
  Museum 
  included 
  by 
  authors 
  in 
  the 
  genus 
  

   Ornithochelrus, 
  and 
  allot 
  them 
  to 
  their 
  particular 
  genus, 
  as 
  

   detailed 
  above. 
  

  

  Oi'nithocheirus 
  clavirostris, 
  R. 
  Owen. 
  

   Rep. 
  Meso. 
  Form. 
  (1874) 
  pt. 
  i. 
  p. 
  G, 
  ^\. 
  i. 
  figs. 
  1-4. 
  

  

  Wealden 
  (Hastings 
  Sand), 
  St. 
  Leonard's-on-Sea. 
  

  

  In 
  regard 
  to 
  this 
  specimen 
  Owen 
  f 
  was 
  loth 
  to 
  believe 
  that 
  

   the 
  "pair 
  of 
  teeth 
  so 
  anomalously 
  located 
  ^^ 
  (above 
  the 
  

   palate) 
  was 
  due 
  to 
  anything 
  but 
  an 
  accident. 
  Seelev 
  

   suspected 
  that 
  the 
  bone 
  would 
  prove 
  to 
  be 
  the 
  dentary, 
  but 
  

   the 
  presence 
  of 
  the 
  palatal 
  ridge 
  determines 
  it 
  to 
  be 
  the 
  

   premaxillary. 
  Neither 
  Owen 
  nor 
  Seeley 
  apparently 
  con- 
  

   sidered 
  the 
  great 
  amount 
  of 
  attrition 
  to 
  which 
  each 
  of 
  the 
  

   specimens 
  had 
  been 
  subjected. 
  The 
  variation 
  in 
  the 
  section 
  

   of 
  the 
  teeth 
  appears 
  purely 
  accidental, 
  according 
  to 
  the 
  

   degree 
  of 
  wear 
  the 
  bone 
  has 
  undergone. 
  From 
  a 
  careful 
  

   examination 
  of 
  the 
  type-specimen 
  we 
  are 
  confident 
  that 
  

   Ornithocheirus 
  (Coluborhynchus) 
  clavirostris 
  is 
  a 
  synonym 
  of 
  

   O. 
  simus 
  and 
  O. 
  looodwardi, 
  that 
  they 
  are 
  all 
  premaxillary 
  

   bones, 
  and 
  that 
  the 
  position 
  of 
  the 
  teeth, 
  which 
  would 
  indeed 
  

   be 
  anomalous 
  above 
  the 
  palate, 
  is 
  to 
  be 
  explained 
  very 
  

   simply 
  : 
  the 
  wearing 
  away 
  of 
  the 
  tip 
  of 
  the 
  snout 
  has 
  

   exposed 
  the 
  bases 
  of 
  these 
  teeth, 
  and 
  not 
  the 
  foot 
  of 
  tlieir 
  

   crowns 
  near 
  the 
  alveoli, 
  as 
  shown 
  by 
  the 
  restoration 
  (PI, 
  XXII. 
  

   fig. 
  5). 
  A 
  similar 
  worn 
  condition 
  of 
  the 
  sides 
  of 
  this 
  

   specimen 
  has 
  displayed 
  the 
  bases 
  of 
  the 
  teeth 
  here 
  also. 
  

   Thus 
  it 
  becomes 
  in 
  all 
  respects 
  similar 
  to 
  0. 
  simus 
  

  

  * 
  R. 
  Owen, 
  Rep. 
  Cret. 
  Form. 
  (Mon. 
  Pal. 
  Soc. 
  18G1), 
  Suppl. 
  iii. 
  tab 
  i 
  

   fig. 
  5. 
  

   t 
  Id. 
  ibid. 
  (Mon. 
  Pal. 
  Soc. 
  1874) 
  pt. 
  i. 
  p. 
  7. 
  

  

  