﻿Mr. 
  J. 
  W. 
  Gregory 
  on 
  Zeuglopleurus. 
  491 
  

  

  relation 
  to 
  tlie 
  sutures. 
  It 
  includes 
  the 
  recent 
  genus 
  Trigono- 
  

   cidaris, 
  a 
  good 
  number 
  of 
  extinct 
  Tertiary 
  genera, 
  sucli 
  as 
  

   Arackniopleurus, 
  Dictyopleurus, 
  &c, 
  and 
  the 
  Cretaceous 
  and 
  

   possibly 
  Oligoccno 
  genus 
  Glyphocyphus 
  ; 
  and 
  to 
  these 
  must 
  

   be 
  added 
  a 
  new 
  genus 
  to 
  include 
  a 
  series 
  of 
  specimens 
  from 
  

   the 
  Chalk 
  of 
  Kent 
  and 
  Sussex. 
  Dr. 
  Duncan 
  had 
  examined 
  

   one 
  of 
  the 
  specimens, 
  and 
  recognizing 
  that 
  it 
  must 
  be 
  assigned 
  

   to 
  a 
  new 
  genus 
  named 
  it 
  Zeuglopleurus 
  ; 
  finding 
  that 
  I 
  had 
  

   also 
  been 
  studying 
  the 
  specimens, 
  he 
  kindly 
  lent 
  me 
  his 
  

   notes, 
  for 
  which, 
  as 
  they 
  have 
  been 
  of 
  great 
  assistance, 
  I 
  

   must 
  express 
  to 
  him 
  my 
  best 
  thanks. 
  

  

  The 
  genus 
  Glyphocyphus 
  was 
  established 
  by 
  Jules 
  llaime 
  

   in 
  1853* 
  for 
  Temnopleurus 
  pulchellus, 
  Sorignet 
  f, 
  a 
  species 
  

   which 
  had 
  even 
  then 
  undergone 
  very 
  varied 
  experiences. 
  

   He 
  defined 
  the 
  genus 
  as 
  characterized 
  by 
  the 
  possession 
  of 
  

   crenulate 
  and 
  perforate 
  tubercles, 
  horizontal 
  pairs 
  of 
  pores 
  

   arranged 
  in 
  a 
  straight 
  vertical 
  series, 
  and 
  with 
  one 
  large 
  

   tubercle 
  on 
  each 
  plate 
  with 
  its 
  borders 
  strongly 
  "taille'sen 
  

   biseau." 
  This 
  very 
  satisfactory 
  diagnosis 
  was, 
  however, 
  

   confused 
  by 
  subsequent 
  workers. 
  

  

  Desor 
  redescribed 
  the 
  genus 
  in 
  1856 
  J, 
  and 
  stated, 
  among 
  

   other 
  generic 
  characters, 
  that 
  the 
  tubercles 
  were 
  neither 
  

   crenulate 
  nor 
  perforate, 
  neither 
  of 
  which 
  features 
  were 
  indi- 
  

   cated 
  in 
  his 
  specimens, 
  as 
  they 
  are 
  often 
  difficult 
  of 
  recog- 
  

   nition 
  in 
  badly 
  preserved 
  material. 
  Desor, 
  however, 
  attached 
  

   little 
  value 
  to 
  the 
  absence 
  of 
  crenulations 
  and 
  emphasized 
  the 
  

   sutural 
  impressions, 
  which 
  had 
  been 
  overlooked 
  by 
  previous 
  

   observers 
  except 
  Sorignet, 
  as 
  the 
  essential 
  character; 
  in 
  con- 
  

   sequence 
  he 
  brought 
  into 
  the 
  genus 
  a 
  series 
  of 
  species 
  pre- 
  

   viously 
  distributed 
  between 
  Arbacia, 
  Cyphosoma, 
  and 
  Echi- 
  

   nopsis 
  ; 
  he 
  showed, 
  moreover, 
  that 
  Sorignet's 
  T. 
  pulchellus 
  

   was 
  the 
  same 
  species 
  as 
  the 
  Echinus 
  radiatus, 
  lloninghaus, 
  

   which 
  is 
  therefore 
  the 
  type, 
  while 
  Temnopleurus 
  pulchellus, 
  

   with 
  Echinopsis 
  depressa, 
  Ag., 
  and 
  Echinopsis 
  latipora, 
  Ag., 
  

   must, 
  be 
  reduced 
  to 
  synonyms, 
  amongst 
  which 
  Desor 
  also 
  

   reckoned 
  Echinc-pais 
  pusillus, 
  Rcemer. 
  

  

  Later 
  in 
  the 
  same 
  year 
  Dr. 
  S. 
  P. 
  Woodward 
  § 
  corrected 
  

   Desor's 
  error 
  as 
  to 
  the 
  absence 
  of 
  crenulation 
  and 
  perfora- 
  

   tion 
  in 
  the 
  tubercles 
  of 
  the 
  type 
  species 
  of 
  Glyphocyphus, 
  

  

  * 
  D'Archiac 
  and 
  Jules 
  Haime, 
  ' 
  Description 
  des 
  aniniaux 
  fossiles 
  du 
  

   groupe 
  luuiimulitique 
  de 
  l'lnde,' 
  t. 
  i. 
  (Paris, 
  185:3), 
  p. 
  -J02. 
  

  

  f 
  ' 
  Oursins 
  fossiles 
  de 
  deux 
  arrondisseinents 
  du 
  doparteniont 
  de 
  l'Eure 
  

   (Vernon, 
  1850), 
  pp. 
  31-33. 
  

  

  X 
  ' 
  Synopsis 
  des 
  Echinides 
  fossiles,' 
  feuille 
  13 
  (1856), 
  pp. 
  102-104, 
  

   pi. 
  xvii. 
  fi^s. 
  1-5. 
  

  

  § 
  Decades 
  Geol. 
  Surv. 
  no. 
  v. 
  (London, 
  1856), 
  Appendix, 
  p. 
  3. 
  

  

  