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  253 
  

  

  1853. 
  Glossodus 
  mantellii, 
  0. 
  G. 
  Costa, 
  Atti 
  Accad. 
  Pontan. 
  vol. 
  vii. 
  

  

  p. 
  28. 
  

   1856. 
  Coelodus 
  mantelli, 
  J. 
  J. 
  Heckel, 
  Denkschr. 
  k. 
  Akad. 
  Wiss., 
  

  

  math.-naturw. 
  01. 
  vol. 
  xi. 
  p. 
  203. 
  

  

  Type. 
  Jaws 
  ; 
  British 
  Museum. 
  

  

  A 
  species 
  of 
  small 
  or 
  moderate 
  size, 
  known 
  only 
  by 
  the 
  dentition. 
  

   Teeth 
  of 
  median 
  series 
  on 
  vomer 
  somewhat 
  more 
  than 
  twice 
  as 
  

   broad 
  as 
  long, 
  with 
  a 
  concave 
  posterior 
  margin, 
  sometimes 
  mesially 
  

   constricted 
  ; 
  teeth 
  of 
  two 
  lateral 
  series 
  nearly 
  equal 
  in 
  size, 
  slightly 
  

   elongated 
  antero-posteriorly, 
  and 
  their 
  width 
  together 
  not 
  equalling 
  

   that 
  of 
  the 
  median 
  series. 
  Teeth 
  of 
  principal 
  series 
  on 
  the 
  splenial 
  

   bone 
  not 
  more 
  than 
  twice 
  as 
  broad 
  as 
  long, 
  scarcely 
  equalling 
  in 
  

   width 
  the 
  two 
  outer 
  series, 
  of 
  which 
  the 
  innermost 
  is 
  nearly 
  twice 
  

   as 
  wide 
  as 
  the 
  outermost 
  ; 
  a 
  row 
  within 
  the 
  principal 
  series 
  very 
  

   rarely 
  represented 
  even 
  by 
  scattered 
  small 
  teeth. 
  All 
  the 
  teeth, 
  

   when 
  unworn, 
  with 
  a 
  deep 
  apical 
  pit, 
  not 
  crenulated 
  on 
  the 
  

   margin. 
  

  

  Form. 
  <$f 
  Log. 
  Wealden 
  : 
  Sussex. 
  Variety 
  in 
  Purbeckian 
  : 
  Dorset- 
  

   shire 
  and 
  N. 
  Germany 
  \ 
  

  

  2690, 
  2698, 
  2709. 
  28415, 
  28417. 
  Series 
  of 
  eight 
  type 
  specimens 
  

   described 
  and 
  figured 
  by 
  Agassiz, 
  torn. 
  cit. 
  pi. 
  lxxii. 
  a. 
  

   figs. 
  6-9, 
  11-14, 
  wanting 
  the 
  original 
  of 
  fig. 
  10; 
  

   Wealden, 
  Tilgate 
  Forest, 
  Sussex. 
  Mantell 
  Coll, 
  

  

  2700, 
  2707, 
  28416. 
  Three 
  specimens 
  of 
  the 
  vomerine 
  dentition, 
  the 
  

   first 
  large 
  and 
  imperfect 
  ; 
  Tilgate 
  Forest. 
  Mantell 
  Coll. 
  

  

  P. 
  4392. 
  Vomerine 
  dentition, 
  wanting 
  outermost 
  series 
  of 
  teeth 
  ; 
  

   Tilgate 
  Forest. 
  Enniskillen 
  Coll, 
  

  

  49115. 
  Two 
  imperfect 
  abraded 
  specimens; 
  Wealden, 
  Tunbridge 
  

   Wells. 
  Mrs. 
  Smith's 
  Coll. 
  

  

  1 
  A 
  form 
  of 
  dentition 
  very 
  closely 
  resembling 
  that 
  of 
  Coelodtis 
  mantelli, 
  from 
  

   the 
  Portlandian 
  of 
  Dept. 
  Meuse, 
  France, 
  is 
  also 
  described 
  by 
  J. 
  Cornuel, 
  Bull. 
  

   Soc. 
  Geol. 
  Prance, 
  [3] 
  vol. 
  viii. 
  (1880), 
  p. 
  151, 
  pi. 
  iii. 
  figs. 
  1-15. 
  He 
  names 
  

   two 
  varieties 
  of 
  the 
  vomerine 
  dentition, 
  " 
  Pycnodus 
  mantelli, 
  var. 
  brevis," 
  and 
  

   " 
  var. 
  stricta." 
  Other 
  doubtful 
  portions 
  of 
  vomers 
  from 
  the 
  Neocomian 
  of 
  

   Haute 
  Marne, 
  France, 
  are 
  described 
  by 
  the 
  same 
  author, 
  ibid. 
  vol. 
  v. 
  (1877), 
  

   p. 
  616, 
  pi. 
  xi. 
  figs. 
  23-25, 
  and 
  F. 
  J. 
  Pictet, 
  Mem. 
  Soc. 
  Linn. 
  Normandie, 
  vol. 
  xvi. 
  

   (1872), 
  no. 
  i. 
  p. 
  18, 
  pi. 
  i. 
  fig. 
  4. 
  The 
  species 
  has 
  also 
  been 
  recorded 
  from 
  the 
  

   Wealden 
  and 
  Purbeck 
  of 
  North 
  Germany 
  on 
  the 
  evidence 
  of 
  splenials 
  and 
  

   vomers 
  with 
  widely 
  spaced 
  dentition 
  and 
  with 
  the 
  principal 
  teeth 
  much 
  more 
  

   transversely 
  extended 
  than 
  in 
  the 
  typical 
  English 
  jaw 
  (W. 
  Dunker, 
  Nord- 
  

   deutsch. 
  Wealdenbild. 
  1846, 
  p. 
  65, 
  pi. 
  xv. 
  figs. 
  19, 
  20, 
  and 
  C. 
  Struckmann, 
  

   Wealdenbild. 
  Hannover, 
  1880, 
  p. 
  89, 
  pi. 
  iii. 
  figs. 
  6, 
  7). 
  

  

  