﻿WEIGHT 
  AND 
  ADAMS 
  MALTESE 
  ECHINODERMS. 
  479 
  

  

  11. 
  Clypeaster 
  latirostris, 
  Agass. 
  

  

  Echinus, 
  sp., 
  Scilla, 
  Corp. 
  Mar. 
  Lapid. 
  tab. 
  10. 
  fig. 
  2. 
  

  

  Clypeaster 
  latirostris, 
  Agassiz, 
  Cat. 
  Syst. 
  Echin., 
  1840, 
  p. 
  6. 
  

  

  Clypeaster 
  Scillce, 
  Agassiz 
  & 
  Desor 
  (pars), 
  Cat. 
  Raisonne 
  des 
  

   Eehinides, 
  1846, 
  p. 
  73. 
  

  

  Clypeaster 
  scutellatus, 
  Desor, 
  Synopsis 
  des 
  Eehinides 
  Foss. 
  1858, 
  

   p. 
  242. 
  

  

  Clypeaster 
  latirostris, 
  Michelin, 
  Monogr. 
  des 
  Clypeastres 
  Eoss., 
  

   1861, 
  pi. 
  15, 
  p. 
  137. 
  

  

  Form 
  in 
  general 
  snbcircnlar, 
  compressed, 
  pentagonal, 
  with 
  ronnded 
  

   angles 
  ; 
  border 
  very 
  thin, 
  especially 
  posteriorly 
  ; 
  upper 
  surface 
  a 
  

   little 
  elevated 
  under 
  the 
  petaloid 
  ambulacra, 
  with 
  a 
  flat 
  margin 
  

   beyond 
  ; 
  under 
  surface 
  flat, 
  deeply 
  concave 
  towards 
  the 
  peristome, 
  

   with 
  deep 
  ambulacral 
  sulci 
  radiating 
  from 
  the 
  angles 
  to 
  the 
  border 
  ; 
  

   median 
  summit 
  often 
  compressed 
  ; 
  apical 
  disk 
  small. 
  Madreporiform 
  

   body 
  forming 
  a 
  convex 
  prominence, 
  which 
  nearly 
  conceals 
  all 
  the 
  

   other 
  elements 
  of 
  the 
  disk 
  ; 
  petaloid 
  ambulacra 
  convex, 
  and 
  undu- 
  

   lated 
  towards 
  the 
  middle, 
  extending 
  more 
  than 
  halfway 
  between 
  

   the 
  summit 
  and 
  the 
  border 
  ; 
  poriferous 
  zones 
  slightly 
  depressed 
  ; 
  

   inner 
  series 
  of 
  pores 
  small 
  and 
  round, 
  external 
  series 
  elongated 
  ; 
  

   septa 
  carrying 
  from 
  8 
  to 
  10 
  tubercles 
  ; 
  interporiferous 
  zones 
  elevated, 
  

   and 
  covered 
  with 
  close-set 
  tubercles 
  ; 
  interambulacral 
  areas 
  like- 
  

   wise 
  elevated 
  and 
  covered 
  with 
  tubercles 
  set 
  wide 
  apart 
  ; 
  surface 
  

   of 
  the 
  test 
  between 
  the 
  areolas 
  of 
  the 
  tubercles 
  covered 
  with 
  a 
  

   fine 
  granulation, 
  which 
  is 
  best 
  seen 
  near 
  the 
  border 
  ; 
  base 
  flat, 
  

   concave 
  towards 
  the 
  mouth 
  -opening 
  ; 
  peristome 
  round, 
  at 
  the 
  bottom 
  

   of 
  a 
  deep 
  cavity; 
  vent 
  submarginal, 
  cordiform, 
  with 
  the 
  angle 
  towards 
  

   the 
  mouth 
  ; 
  test 
  composed 
  of 
  thick 
  plates. 
  

  

  Dimensions. 
  — 
  Length 
  4 
  inches 
  ; 
  breadth 
  3-| 
  inches 
  ; 
  height 
  -| 
  inch. 
  

  

  Affinities 
  and 
  differences. 
  — 
  This 
  species 
  resembles 
  C. 
  marginatum, 
  

   but 
  it 
  is 
  much 
  smaller 
  and 
  less 
  elevated 
  in 
  the 
  centre 
  ; 
  the 
  petaloid 
  

   ambulacra 
  are 
  not 
  so 
  prominent, 
  the 
  border 
  is 
  rounder, 
  and 
  the 
  test 
  

   thicker 
  than 
  in 
  that 
  species. 
  It 
  very 
  much 
  resembles 
  C. 
  laganoides, 
  

   Ag., 
  from 
  the 
  Miocene 
  of 
  Corsica. 
  

  

  Stratigraphical 
  position. 
  — 
  " 
  Collected 
  from 
  bed 
  No. 
  5 
  : 
  I 
  find 
  this 
  

   Urchin 
  often 
  associated 
  with 
  Scutella 
  subrotunda, 
  Leske, 
  and 
  by 
  no 
  

   means 
  rare. 
  These 
  two, 
  as 
  far 
  as 
  I 
  have 
  yet 
  observed, 
  are 
  charac- 
  

   teristic 
  of 
  the 
  Lower 
  Limestone." 
  (A. 
  L. 
  A.) 
  

  

  12. 
  Scutella 
  subrotunda, 
  Leske. 
  

  

  Stratigraphical 
  position. 
  — 
  " 
  This 
  species 
  is 
  plentiful 
  in 
  the 
  Lower 
  

   Limestone 
  No. 
  5, 
  and 
  in 
  the 
  transition 
  between 
  it 
  and 
  No. 
  4. 
  It 
  is 
  

   usually 
  associated 
  with 
  the 
  Echinolampades 
  of 
  No. 
  5." 
  (A. 
  L. 
  A.) 
  

  

  13. 
  Pygorhynchus 
  Vassali, 
  Wright. 
  PI. 
  XXII. 
  figs. 
  6 
  a 
  — 
  6 
  c. 
  

  

  Stratigraphical 
  position. 
  — 
  Collected 
  from 
  one 
  of 
  the 
  nodular 
  beds 
  

   of 
  No. 
  4, 
  at 
  Malta, 
  where 
  it 
  is 
  very 
  rare. 
  

  

  Collections. 
  — 
  Mus. 
  Royal 
  School 
  of 
  Mines 
  ; 
  Geological 
  Society 
  

   cabinet 
  of 
  the 
  Earl 
  of 
  Ducie. 
  

  

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