﻿WEIGHT 
  AND 
  ADAMS 
  MALTESE 
  ECHINODEEMS. 
  487 
  

  

  Stratigraphical 
  position. 
  — 
  Collected 
  from 
  bed 
  No. 
  1, 
  in 
  a 
  marly 
  

   stratum 
  of 
  the 
  Upper 
  Limestone, 
  at 
  Malta. 
  

   Collections. 
  — 
  My 
  cabinet. 
  

  

  31. 
  Pericosmtjs 
  laths, 
  Agassiz. 
  

  

  Stratigraphical 
  position. 
  — 
  Collected 
  at 
  Malta 
  from 
  bed 
  No. 
  4, 
  

   both 
  from 
  the 
  calcareous 
  sandstone 
  and 
  its 
  nodule-beds 
  ; 
  the 
  speci- 
  

   mens 
  from 
  the 
  sandstone 
  have 
  their 
  fascioles 
  well 
  preserved. 
  I 
  

   have 
  one 
  specimen 
  from 
  the 
  Miocene 
  of 
  Corsica. 
  

  

  Collections. 
  — 
  Museum 
  of 
  the 
  Geological 
  Society 
  ; 
  my 
  cabinet. 
  

  

  32. 
  Toxobrisstjs 
  crescentictts, 
  Wright. 
  

  

  Stratigraphical 
  position. 
  — 
  Collected 
  at 
  Malta, 
  from 
  the 
  calcareous 
  

   sandstone 
  of 
  bed 
  No. 
  4. 
  I 
  know 
  only 
  the 
  specimen 
  I 
  figured 
  in 
  the 
  

   Ann. 
  and 
  Mag. 
  Nat. 
  Hist. 
  2nd 
  series, 
  vol. 
  xv. 
  pi. 
  6. 
  fig. 
  1, 
  and 
  which 
  

   is 
  in 
  my 
  cabinet. 
  

  

  Genus 
  Prenaster, 
  Desor, 
  1853. 
  

  

  Urchins 
  with 
  an 
  ovoid 
  inflated 
  test, 
  and 
  the 
  ambulacral 
  summit 
  

   very 
  excentral. 
  Petaloid 
  ambulacra 
  very 
  little 
  depressed, 
  nearly 
  

   level 
  with 
  the 
  surface, 
  very 
  divergent, 
  and 
  often 
  even 
  perpendicular 
  ; 
  

   anteal 
  sulcus 
  nearly 
  obliterated. 
  Peripetalous 
  fasciole 
  incomplete, 
  

   absent 
  from 
  the 
  anterior 
  border. 
  Lateral 
  fasciole 
  entirely 
  encircling 
  

   the 
  lower 
  border 
  of 
  the 
  test. 
  The 
  species 
  are 
  all 
  extinct, 
  and 
  found 
  

   in 
  the 
  Upper 
  Cretaceous 
  rocks 
  and 
  in 
  the 
  Eocene 
  Tertiaries. 
  Our 
  

   species 
  from 
  Malta 
  is 
  the 
  only 
  one 
  yet 
  catalogued 
  from 
  the 
  Miocene 
  

   deposits. 
  

  

  33. 
  Prenaster 
  excentricus, 
  Wright. 
  PI. 
  XXII. 
  fig. 
  3. 
  

   Stratigraphical 
  position. 
  — 
  The 
  specimens, 
  which 
  are 
  all 
  much 
  com- 
  

   pressed, 
  were 
  collected 
  from 
  bed 
  No. 
  1 
  at 
  Malta. 
  

  

  Collections. 
  — 
  Museum 
  of 
  the 
  Geological 
  Society 
  ; 
  Royal 
  School 
  of 
  

   Mines 
  ; 
  the 
  Earl 
  of 
  Ducie. 
  

  

  34. 
  Eupatagus 
  Konincxi, 
  Wright. 
  PI. 
  XXII. 
  figs. 
  5 
  a 
  — 
  5 
  c. 
  

   Affinities 
  and 
  differences. 
  — 
  This 
  species 
  is 
  distinguished 
  from 
  E. 
  

  

  ornatus, 
  Defr., 
  in 
  being 
  smaller, 
  having 
  fewer 
  large 
  tubercles 
  within 
  

   the 
  peripetalous 
  fasciole, 
  and 
  being 
  more 
  elevated 
  behind 
  ; 
  the 
  basal 
  

   tubercles 
  and 
  the 
  pairs 
  of 
  interambulacra 
  are 
  likewise 
  smaller 
  and 
  

   more 
  numerous. 
  

  

  Stratigraphical 
  position. 
  — 
  " 
  This 
  Urchin 
  is 
  common 
  in 
  bed 
  No. 
  4, 
  

   and 
  in 
  its 
  nodule-bed 
  also 
  in 
  the 
  upper 
  portions 
  of 
  No. 
  5." 
  (A. 
  L. 
  A.) 
  

  

  35. 
  Spatangus 
  ocellatus, 
  Defrance. 
  PI. 
  XXI. 
  figs. 
  1 
  a, 
  1 
  b. 
  

   Affinities 
  and 
  differences. 
  — 
  This 
  Urchin 
  was 
  described 
  in 
  my 
  me- 
  

   moir 
  on 
  the 
  Maltese 
  Echinoderms 
  as 
  S. 
  Hoffmanni, 
  Goldf., 
  in 
  con- 
  

   sequence 
  of 
  S. 
  ocellatus, 
  Defr., 
  having 
  been 
  sent 
  to 
  me 
  from 
  Belgium 
  

   as 
  S. 
  Hoffmanni 
  ; 
  this 
  occasioned 
  the 
  error 
  in 
  my 
  determination. 
  

   S. 
  Nicoleti, 
  Agass., 
  from 
  the 
  Molasse 
  of 
  Chaux-de-fonds, 
  is 
  stated 
  by 
  

   M. 
  Desor 
  to 
  be 
  identical 
  with 
  S. 
  ocellatus, 
  Defr. 
  This 
  species 
  is 
  so 
  

   remarkable 
  for 
  the 
  size 
  and 
  depth 
  of 
  the 
  areolas 
  of 
  the 
  large 
  tubercles 
  

   on 
  the 
  upper 
  surface 
  of 
  the 
  test, 
  from 
  the 
  centre 
  of 
  which 
  the 
  

  

  