﻿PYCNODONTID^. 
  205 
  

  

  in 
  Agassiz' 
  handwriting, 
  described 
  and 
  figured 
  in 
  Proc. 
  

   Geol. 
  Assoc, 
  vol. 
  xi. 
  (1890), 
  p. 
  299, 
  pi. 
  iii. 
  fig. 
  27 
  ; 
  Stones- 
  

   field. 
  EnnishilUn 
  Coll. 
  

  

  P. 
  1666. 
  Similar 
  splenial 
  dentition 
  of 
  left 
  side 
  ; 
  Stonesfield. 
  

  

  Egerton 
  Coll. 
  

  

  P. 
  3734. 
  Pour 
  more 
  imperfect 
  small 
  examples 
  of 
  the 
  splenial 
  den- 
  

   tition 
  ; 
  Stonesfield. 
  Ennishillen 
  Coll. 
  

  

  Mesodon 
  bucklandi 
  (Agassiz). 
  

  

  1833-44. 
  Pycnodus 
  bucklandi, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  i. 
  

  

  p. 
  16, 
  pt. 
  ii. 
  p. 
  192, 
  pi. 
  lxxii. 
  a. 
  fig. 
  15 
  (non 
  figs. 
  16-22). 
  

   1839-44. 
  Pycnodus 
  didymus, 
  L. 
  Agassiz, 
  ibid. 
  p. 
  193, 
  pi. 
  lxxii. 
  a. 
  figs. 
  24, 
  

  

  25. 
  [Mandibular 
  dentition 
  ; 
  British 
  Museum.] 
  

   1839-44. 
  Pycnodus 
  ovalis, 
  L. 
  Agassiz, 
  ibid. 
  p. 
  195, 
  pi. 
  lxxii. 
  a. 
  fig. 
  5. 
  

  

  [Vomerine 
  dentition 
  ; 
  Bristol 
  Museum.] 
  

   1840. 
  Pycnodus 
  bucklandi, 
  R. 
  Owen, 
  Odontogr. 
  pi. 
  xxxiv. 
  fig. 
  2. 
  

   1840. 
  Pycnodus 
  didymus, 
  R. 
  Owen, 
  ibid. 
  pi. 
  xxxiv. 
  fig. 
  3. 
  

   1844. 
  Pycnodus 
  obtusus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  ii. 
  p. 
  199 
  

  

  (name 
  only). 
  [Vomer; 
  British 
  Museum.] 
  

   1871. 
  Pycnodus 
  bucklandi, 
  J. 
  Phillips, 
  Geol. 
  Oxford, 
  p. 
  179 
  ; 
  woodc. 
  

  

  xxxix. 
  figs. 
  4, 
  5. 
  

   1871. 
  Pycnodus 
  didymus, 
  J. 
  Phillips, 
  ibid. 
  p. 
  179, 
  woodc. 
  xxxix. 
  fig. 
  6. 
  

   1885. 
  Mesodon 
  bucklandi, 
  F. 
  Bassani, 
  Atti 
  Soc. 
  Ital. 
  Sci. 
  Nat. 
  

  

  vol. 
  xxviii. 
  p. 
  160. 
  

  

  1889. 
  Mesodon 
  bucklandi, 
  A.- 
  S. 
  Woodward, 
  Geol. 
  Mag. 
  [3] 
  vol. 
  vi. 
  

   p. 
  454. 
  

  

  1890. 
  Mesodon 
  bucklandi, 
  A. 
  S. 
  Woodward, 
  Proc. 
  Geol. 
  Assoc, 
  vol. 
  xi. 
  

   p. 
  297, 
  pi. 
  iii. 
  figs. 
  20-22, 
  

  

  Type. 
  Vomerine 
  dentition 
  ; 
  Oxford 
  Museum. 
  

  

  A 
  species 
  of 
  large 
  size, 
  known 
  only 
  by 
  the 
  dentition. 
  Teeth 
  

   smooth, 
  often 
  irregular 
  in 
  outline, 
  the 
  rounded 
  contour 
  being, 
  fre- 
  

   quently 
  interrupted 
  by 
  angulations. 
  Vomerine 
  teeth 
  well 
  spaced 
  ; 
  

   those 
  of 
  the 
  median 
  series, 
  except 
  quite 
  anteriorly, 
  less 
  than 
  twice 
  

   as 
  broad 
  as 
  long, 
  but 
  their 
  breadth 
  exceeding 
  that 
  of 
  the 
  two 
  

   lateral 
  series 
  ; 
  teeth 
  of 
  the 
  inner 
  lateral 
  series 
  much 
  larger 
  than 
  

   those 
  of 
  the 
  outer 
  series, 
  not 
  regularly 
  alternating 
  ; 
  a 
  few 
  small 
  

   scattered 
  teeth 
  also 
  occurring 
  irregularly 
  between 
  the 
  median 
  and 
  

   inner 
  lateral 
  series. 
  Splenial 
  teeth 
  well 
  spaced, 
  those 
  of 
  the 
  

   principal 
  series 
  almost 
  twice 
  as 
  broad 
  as 
  long, 
  flanked 
  within 
  by 
  a 
  

   single 
  row 
  of 
  small 
  rounded 
  teeth 
  and 
  externally 
  by 
  three 
  regular 
  

   series, 
  of 
  which 
  the 
  second 
  only 
  equals 
  the 
  innermost 
  row 
  in 
  size, 
  

   while 
  the 
  first 
  is 
  slightly 
  larger, 
  and 
  the 
  third 
  (or 
  outermost) 
  much 
  

   larger 
  than 
  all 
  except 
  the 
  principal 
  series. 
  

  

  