﻿PYCtfODONTIDJS. 
  

  

  217 
  

  

  large, 
  closely-arranged 
  teeth, 
  mostly 
  circular, 
  all 
  smooth, 
  disposed 
  

   in 
  three 
  nearly 
  regular 
  longitudinal 
  series. 
  Anteriorly 
  the 
  three 
  

   series 
  are 
  about 
  equal 
  in 
  size 
  ; 
  posteriorly 
  the 
  median 
  teeth 
  are 
  

   slightly 
  the 
  larger. 
  

  

  Form. 
  Sf 
  Loc. 
  Cenomanian 
  : 
  Cambridge. 
  

  

  P. 
  7238. 
  The 
  type 
  specimen, 
  described 
  and 
  figured 
  loc. 
  cit. 
  ; 
  Cam- 
  

   bridge 
  Greensand, 
  Cambridge. 
  The 
  dentition 
  measures 
  

   0*02 
  in 
  maximum 
  width 
  and 
  0-04 
  in 
  length. 
  Jesson 
  Coll. 
  

  

  The 
  following 
  form 
  of 
  vomer 
  may 
  belong 
  either 
  to 
  Athrodon 
  or 
  

   to 
  Mesodon 
  : 
  — 
  

  

  P. 
  7186. 
  Imperfect 
  vomerine 
  dentition, 
  shown 
  of 
  the 
  natural 
  size 
  

   in 
  PI. 
  XYII. 
  fig. 
  2 
  ; 
  Portland 
  Stone, 
  near 
  Weymouth. 
  

   The 
  teeth 
  are 
  widely 
  spaced 
  on 
  a 
  transversely-convex 
  

   surface, 
  and 
  arranged 
  in 
  seven 
  series. 
  All 
  are 
  smooth, 
  

   but 
  much 
  worn; 
  and 
  even 
  the 
  principal 
  median 
  teeth 
  

   are 
  scarcely 
  broader 
  than 
  long. 
  Purchased, 
  1894. 
  

  

  P. 
  3750. 
  Left 
  lateral 
  teeth 
  of 
  a 
  similar 
  vomer 
  ; 
  Portland 
  Stone, 
  

   near 
  Weymouth. 
  Enniskillen 
  Coll. 
  

  

  The 
  following 
  species 
  have 
  also 
  been 
  founded 
  on 
  detached 
  splenial 
  

   bones, 
  of 
  which 
  there 
  are 
  no 
  examples 
  in 
  the 
  Collection 
  : 
  — 
  

  

  Athrodon 
  boloniensis, 
  H. 
  E. 
  Sauvage, 
  Bull. 
  Soc. 
  Geol. 
  Prance, 
  [3] 
  

   vol. 
  viii. 
  (1880), 
  p. 
  531, 
  pi. 
  xix. 
  fig. 
  6. 
  — 
  Lower 
  Kirn- 
  

   meridgian 
  ; 
  Brecque-recque, 
  Boulogne. 
  [School 
  of 
  Mines, 
  

   Paris.] 
  

  

  Athrodon 
  jorofusidens, 
  A. 
  S. 
  Woodward, 
  Geol. 
  Mag. 
  [3] 
  vol. 
  x. 
  

   (1893), 
  p. 
  435. 
  Pycnodus 
  jprofusidens, 
  J. 
  Cornuel, 
  Bull. 
  

   Soc. 
  Geol. 
  France, 
  [3] 
  vol. 
  v. 
  (1877), 
  p. 
  609, 
  pi. 
  xi. 
  figs. 
  3-6. 
  

   Mesodon 
  prof 
  usidens, 
  A. 
  Gaudry, 
  Enchain. 
  Monde 
  Anim., 
  

   Foss. 
  Second. 
  (1890), 
  p. 
  164, 
  fig. 
  262.— 
  Neocomian 
  ; 
  

   Wassy, 
  Haute 
  Marne. 
  

  

  Athrodon 
  tenuis, 
  A. 
  S. 
  Woodward, 
  loc. 
  cit. 
  (1893), 
  p. 
  435, 
  pi. 
  xvi. 
  

   fig. 
  2. 
  — 
  Lower 
  Senonian; 
  Lonzee,near 
  Gembloux, 
  Belgium. 
  

   [Brussels 
  Eoyal 
  Museum 
  of 
  Natural 
  History.] 
  

  

  Athrodon 
  ivittei, 
  H.E. 
  Sauvage, 
  loc. 
  cit. 
  (1880), 
  p. 
  531. 
  Mesodon 
  

   ivittei, 
  K. 
  Fricke, 
  Palasontogr. 
  vol. 
  xxii. 
  (1875), 
  p. 
  364, 
  

   pi. 
  xix. 
  fig. 
  15. 
  — 
  Lower 
  Kimmeridgian 
  ; 
  Hanover. 
  

  

  An 
  imperfect 
  vomerine 
  dentition 
  from 
  the 
  Cambridge 
  Greensand, 
  

   in 
  the 
  Woodwardian 
  Museum, 
  Cambridge, 
  is 
  also 
  not 
  improbably 
  

   referable 
  to 
  Athrodon 
  (A. 
  S. 
  Woodward, 
  loc. 
  cit. 
  1893, 
  p. 
  435, 
  

   pi. 
  xvi. 
  fig. 
  4). 
  

  

  