﻿Genus 
  Orbitoides 
  of 
  d 
  1 
  Orbigny. 
  211 
  

  

  Be 
  this 
  as 
  it 
  may, 
  these 
  specimens 
  are 
  sufficient 
  to 
  show 
  

   after 
  careful 
  examination 
  not 
  only 
  that 
  they 
  are 
  identical 
  in 
  

   their 
  specific 
  nature 
  with 
  the 
  specimens 
  from 
  Maestricht, 
  but 
  

   that 
  they 
  entirely 
  accord 
  with 
  d'Orbigny's 
  illustrations 
  in 
  his 
  

   ' 
  Cours 
  Element, 
  de 
  Paleont. 
  et 
  de 
  Geologie 
  ' 
  (vol. 
  i. 
  p. 
  193), 
  

   being 
  therefore 
  genuine 
  varieties 
  of, 
  if 
  not 
  identical 
  with 
  my 
  

   Orbitolites 
  Mantelli 
  ('Annals,' 
  I. 
  c. 
  p. 
  442). 
  Thus 
  I 
  observe 
  

   that 
  the 
  vertical 
  papillary 
  eminence 
  of 
  the 
  crust 
  on 
  each 
  side 
  of 
  

   the 
  central 
  plane, 
  although 
  only 
  seen 
  on 
  one 
  side 
  in 
  the 
  speci- 
  

   mens 
  from 
  Maestricht, 
  is 
  perfectly 
  developed 
  on 
  both 
  sides 
  in 
  

   those 
  from 
  the 
  south-west 
  of 
  France, 
  and 
  therefore 
  identical 
  

   with 
  d'Orbigny's 
  " 
  Profil 
  " 
  (< 
  Cours,' 
  I. 
  c.) 
  ; 
  also 
  that 
  the 
  

   sinuous 
  lines 
  on 
  the 
  surface 
  radiating 
  from 
  this 
  eminence 
  

   to 
  the 
  circumference 
  in 
  d'Orbigny's 
  adjoining 
  representation 
  

   are 
  equally 
  identical. 
  These 
  lines 
  are 
  intended 
  for 
  ridges 
  of 
  

   shell-substance 
  continuous 
  with 
  that 
  forming 
  the 
  central 
  

   eminence, 
  and 
  radiating 
  at 
  first 
  singly 
  from 
  this 
  point 
  be- 
  

   come 
  so 
  multiplied 
  by 
  subdivision 
  afterwards 
  (that 
  is 
  as 
  they 
  

   approach 
  the 
  circumference) 
  as 
  to 
  spread 
  all 
  over 
  the 
  disk. 
  

   Originally 
  they 
  are 
  derived 
  from 
  the 
  union 
  of 
  granulations 
  

   which 
  more 
  particularly 
  characterize 
  the 
  specimens 
  from 
  

   Maestricht, 
  where 
  they 
  may 
  be 
  seen 
  to 
  be 
  the 
  outer 
  ends 
  of 
  

   the 
  " 
  conical 
  columns 
  " 
  to 
  which 
  I 
  have 
  alluded 
  in 
  my 
  

   description 
  of 
  this 
  form 
  ( 
  l 
  Annals,' 
  I. 
  c. 
  p. 
  445). 
  

  

  Still 
  this 
  does 
  not 
  interfere 
  with 
  what 
  I 
  have 
  endeavoured 
  

   to 
  point 
  out, 
  viz. 
  that 
  the 
  cells 
  of 
  the 
  central 
  plane 
  of 
  d'Or- 
  

   bigny's 
  Orbitoides 
  media 
  present 
  in 
  the 
  horizontal 
  section 
  a 
  

   spheroidal 
  form, 
  and 
  that 
  those 
  of 
  his 
  Orbitoides 
  papyracea 
  

   (' 
  Cours,' 
  vol. 
  ii. 
  p. 
  732) 
  are 
  rectangular 
  — 
  a 
  distinction 
  

   which 
  it 
  is 
  desirable 
  to 
  bear 
  in 
  mind, 
  as 
  at 
  present 
  the 
  term 
  

   "Orbitoides" 
  is 
  indiscriminately 
  used 
  for 
  both 
  kinds, 
  so 
  that 
  

   it 
  is 
  not 
  known 
  when 
  this 
  term 
  is 
  mentioned 
  which 
  kind 
  is 
  

   meant, 
  a 
  circumstance 
  that 
  the 
  following 
  paragraph 
  will 
  show 
  

   to 
  be 
  likely 
  to 
  lead 
  to 
  confusion 
  both 
  palaeontologically 
  and 
  

   geologically. 
  

  

  At 
  present 
  we 
  know 
  that 
  Orbitolites 
  Mantelli 
  has 
  been 
  found 
  

   in 
  the 
  midst 
  of 
  a 
  bed 
  of 
  Nummulites 
  subbevigata 
  in 
  Sind, 
  and 
  

   Orbitoides 
  dispansa 
  in 
  one 
  of 
  N. 
  exponens 
  at 
  Lukput, 
  in 
  

   Cutch, 
  in 
  confirmation 
  of 
  which 
  I 
  now 
  possess 
  specimens. 
  

   Hence 
  it 
  is 
  possible 
  that 
  all 
  three 
  may 
  exist 
  somewhere 
  to- 
  

   gether. 
  But 
  there 
  are 
  no 
  Nummulites 
  with 
  Orbitolites 
  Man- 
  

   telli 
  in 
  the 
  Claiborne 
  beds 
  of 
  Alabama, 
  none 
  that 
  I 
  could 
  see 
  

   in 
  the 
  bed 
  of 
  the 
  cliff 
  at 
  Takah, 
  on 
  the 
  south-east 
  coast 
  of 
  

   Arabia, 
  nor 
  in 
  the 
  specimens 
  from 
  the 
  bed 
  at 
  Nal, 
  in 
  

   Jhalawan, 
  nor 
  in 
  those 
  from 
  that 
  of 
  the 
  bank 
  of 
  the 
  river 
  

   Irrawadi 
  discovered 
  by 
  Mr. 
  Theobald 
  — 
  circumstances 
  which 
  

  

  