﻿494 
  Mr. 
  J. 
  W. 
  Gregory 
  on 
  Zeuglopleurus. 
  

  

  certainly 
  not 
  the 
  case 
  in 
  the 
  original 
  figure 
  of 
  the 
  type, 
  though 
  

   it 
  must 
  be 
  admitted 
  that 
  the 
  general 
  facies 
  of 
  this 
  figure 
  

   more 
  resembles 
  that 
  of 
  Echinocyphus 
  than 
  of 
  Glyphocyphus 
  ; 
  

   but 
  as 
  the 
  question 
  cannot 
  be 
  decided 
  without 
  an 
  examination 
  

   of 
  the 
  lost 
  type 
  specimen, 
  it 
  is 
  best 
  to 
  accept 
  it 
  in 
  the 
  sense 
  

   that 
  has 
  been 
  done 
  by 
  all 
  palaeontologists 
  who 
  have 
  written 
  

   upon 
  it. 
  M. 
  Pomel 
  moreover 
  separates 
  * 
  from 
  Echino- 
  

   cyphus 
  the 
  species 
  E. 
  difficilis 
  and 
  E. 
  rotatum 
  as 
  the 
  genus 
  

   Glyptocyphus, 
  owing 
  to 
  the 
  compound 
  ambulacral 
  plates 
  of 
  

   those 
  species 
  consisting 
  of 
  four 
  or 
  five 
  primaries. 
  

  

  This 
  examination 
  of 
  the 
  literature 
  of 
  the 
  genus 
  Glypho- 
  

   cyphus 
  is 
  necessary 
  owing 
  to 
  the 
  confusion 
  that 
  prevailed 
  over 
  

   the 
  type 
  species 
  since 
  its 
  definition 
  by 
  Honinghaus 
  in 
  1820 
  f 
  

   till 
  at 
  least 
  as 
  late 
  as 
  1870, 
  when 
  Nicaise 
  still 
  quoted 
  \ 
  

   T. 
  pulchellus, 
  Sorignet. 
  Even 
  in 
  1875 
  Quenstedt 
  published 
  § 
  

   a 
  diagnosis 
  of 
  Glyphocyphus 
  in 
  which 
  he 
  described 
  the 
  

   tubercles 
  as 
  imperforate 
  and 
  non-crenulate. 
  From 
  it, 
  more- 
  

   over, 
  we 
  learn 
  that 
  all 
  recent 
  authors 
  have 
  accepted 
  the 
  two 
  

   genera 
  Glyjdiocyjdius 
  and 
  Echinocyphus 
  as 
  distinct, 
  and 
  

   their 
  differences 
  may 
  be 
  summarized 
  as 
  that 
  in 
  Glyphocyphus 
  

   (i.) 
  the 
  tubercles 
  are 
  perforate, 
  (ii.) 
  the 
  apical 
  disk 
  is 
  a 
  narrow 
  

   ring 
  of 
  plates 
  all 
  of 
  which 
  enter 
  the 
  anal 
  ring, 
  and 
  (iii.) 
  that 
  

   the 
  furrowing 
  of 
  the 
  sutures 
  is 
  less 
  prominent; 
  whereas 
  in 
  

   Echinocyphus 
  (i.) 
  the 
  tubercles 
  are 
  imperforate, 
  (ii.) 
  the 
  

   apical 
  disk 
  more 
  solid, 
  the 
  paired 
  basals 
  meeting 
  and 
  pushing 
  

   the 
  anus 
  posteriorly, 
  and 
  (iii.) 
  there 
  is 
  more 
  prominent 
  fur- 
  

   rowing 
  of 
  the 
  sutures. 
  

  

  The 
  specimens 
  upon 
  which 
  this 
  new 
  genus 
  is 
  founded 
  have 
  

   apparently 
  been 
  regarded 
  as 
  Glyphocyphus 
  radiatus, 
  which 
  

   they 
  resemble 
  in 
  ornamentation, 
  and 
  have 
  thus 
  been 
  over- 
  

   looked 
  by 
  all 
  previous 
  observers 
  except 
  Reenter. 
  

  

  Zeuglopleurus, 
  n. 
  gen. 
  

  

  Test 
  (figs. 
  1-3, 
  p. 
  500) 
  small, 
  globular, 
  circular, 
  depressed 
  

   below, 
  slightly 
  conical 
  above; 
  sides 
  tumid. 
  Tubercles 
  ar- 
  

   ranged 
  in 
  one 
  or 
  two 
  verlical 
  rows 
  in 
  each 
  ambulacrum, 
  

   slightly 
  smaller 
  than 
  those 
  of 
  the 
  two 
  rows 
  in 
  each 
  interradius. 
  

  

  Apical 
  disk 
  (fig. 
  2) 
  somewhat 
  solid, 
  the 
  two 
  postero-lateral 
  

   radials 
  enter 
  the 
  anal 
  ring 
  ; 
  the 
  antero-lateral 
  pair 
  of 
  basals 
  

  

  * 
  Op. 
  cit. 
  p. 
  87. 
  

  

  t 
  Goldfuss, 
  ' 
  Petrefacta 
  Germanice 
  ' 
  (Dusseldorf), 
  pp. 
  124, 
  125, 
  pi. 
  xl. 
  

  

  \ 
  ' 
  Catalogue 
  des 
  animaux 
  fossiles 
  <le 
  la 
  province 
  de 
  1 
  Algerie,' 
  p. 
  07. 
  

   § 
  ; 
  IVtreiactenkiuide 
  Deutsehlands,' 
  lid. 
  iii, 
  (Leipzig, 
  1870), 
  p. 
  t>92. 
  

  

  