﻿556 
  Mr. 
  R. 
  W. 
  Hooley 
  on 
  the 
  

  

  Os 
  mnominatum. 
  

  

  Examples 
  of 
  the 
  ossa 
  innomiuata 
  are 
  arranged 
  on 
  tablet 
  

   J. 
  b. 
  10, 
  and 
  numbered 
  1-9. 
  In 
  those 
  specimens, 
  where 
  the 
  

   acetabulum 
  is 
  preserved, 
  it 
  is 
  imperforate, 
  and 
  tlie 
  surrounding 
  

   bones 
  anchylosed 
  and 
  apparently 
  near 
  to 
  Ornithostoma 
  

   {Pteranodon) 
  ingens, 
  where 
  the 
  bones 
  are 
  conjoined 
  and 
  the 
  

   acetabulum 
  shallow 
  and 
  imperforate. 
  

  

  Femur. 
  

  

  There 
  is 
  only 
  one 
  perfect 
  specimen 
  of 
  the 
  femur, 
  the 
  other 
  

   examples 
  are 
  fragments. 
  They 
  may 
  be 
  divided 
  into 
  two 
  

   groups 
  : 
  — 
  

  

  (1) 
  Neck 
  and 
  head 
  oblique 
  to 
  the 
  shaft. 
  Great 
  trochanter 
  

  

  weak. 
  Shaft 
  straight 
  and 
  large. 
  Example 
  : 
  

   J. 
  c. 
  2, 
  11, 
  20. 
  

  

  (2) 
  Neck 
  and 
  head 
  very 
  oblique. 
  Great 
  trochanter 
  

  

  robust. 
  Shaft 
  straight 
  and 
  small. 
  Example 
  : 
  

   J. 
  h. 
  11, 
  1. 
  

  

  Both 
  are 
  illustrated 
  in 
  ' 
  Ornithosauria,' 
  pi. 
  viii. 
  figs, 
  .5, 
  6, 
  

   7, 
  and 
  8. 
  In 
  neither 
  group 
  are 
  the 
  head 
  and 
  neck 
  as 
  

   terminal 
  as 
  in 
  Ornithodesinus 
  latidens. 
  The 
  shaft 
  is 
  not 
  

   curved 
  as 
  much 
  as 
  in 
  the 
  American 
  forms; 
  otherwise 
  tlie 
  

   description 
  by 
  Professor 
  Willistoii 
  '^ 
  of 
  tlie 
  femur 
  of 
  Ornitho- 
  

   stoma 
  i^Pterunodon^ 
  ingens 
  is 
  near 
  to 
  Group 
  1 
  and 
  also 
  to 
  

   Nyctosaarus 
  [Ny 
  do 
  dactyl 
  us) 
  -j-. 
  To 
  which 
  genus 
  the 
  speci- 
  

   mens 
  included 
  in 
  Group 
  2 
  belong 
  must 
  remain 
  an 
  open 
  

   question. 
  

  

  In 
  concluding 
  our 
  examination 
  of 
  the 
  Cambridge 
  Green- 
  

   sand 
  material 
  in 
  the 
  Cambridge 
  Museum, 
  Cambridge, 
  we 
  find 
  

   that 
  the 
  jaws 
  divide 
  into 
  five 
  genera 
  — 
  Urmthocheirus 
  , 
  Lon- 
  

   chodectes, 
  Amtjlydectes, 
  Criorhynchus, 
  and 
  Ornithostoma. 
  

  

  On 
  the 
  evidence 
  of 
  the 
  premaxillse 
  Ornithodesmns 
  is 
  

   entirely 
  separated 
  from 
  either 
  genera 
  of 
  the 
  Cambridge 
  

   Greensand, 
  but 
  the 
  fragments 
  of 
  the 
  humeri 
  and 
  ulnae 
  of 
  

   Group 
  A 
  must 
  undoubtedly 
  be 
  incorporated 
  into 
  the 
  same 
  

   family, 
  and 
  there 
  is 
  nothing 
  to 
  prove 
  that 
  the 
  iiumeri 
  and 
  

   ulnae 
  included 
  in 
  Group 
  A 
  should 
  be 
  assigned 
  to 
  reptiles 
  

   possessing 
  premaxillse 
  typical 
  of 
  one 
  of 
  the 
  five 
  genera. 
  

   Neither 
  can 
  any 
  of 
  the 
  other 
  bones 
  of 
  the 
  axial 
  skeleton 
  be 
  

  

  * 
  S. 
  W. 
  Williston, 
  Kansas 
  Univ. 
  Quart. 
  1893-4, 
  ii. 
  p. 
  80. 
  

  

  t 
  Id. 
  Field 
  Col. 
  Mus. 
  Pub. 
  78, 
  geo. 
  ser. 
  1003, 
  vol. 
  ii. 
  Jio. 
  3, 
  p. 
  150. 
  

  

  