﻿480 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  

  

  14. 
  Echinolampas 
  Hayesiantts, 
  Desor. 
  

  

  Stratigraphical 
  position. 
  — 
  This 
  species 
  was 
  collected 
  from 
  the 
  

   Sand-bed 
  No. 
  2, 
  at 
  Malta. 
  It 
  has 
  likewise 
  been 
  found 
  in 
  the 
  Mio- 
  

   cene 
  at 
  Oran, 
  Algeria, 
  Carthagena, 
  Catalonia, 
  and 
  Balistro 
  (Corsica). 
  

  

  Collections. 
  — 
  The 
  Maltese 
  specimen 
  is 
  unique, 
  and 
  is 
  in 
  the 
  cabinet 
  

   of 
  the 
  Earl 
  of 
  Ducie. 
  

  

  15. 
  Echinolampas 
  Latjrillardi, 
  Agassiz. 
  

  

  Stratigraphical 
  position. 
  — 
  Collected 
  from 
  the 
  Marl 
  No. 
  3, 
  and 
  

   the 
  nodular 
  beds 
  of 
  No. 
  4, 
  at 
  Malta, 
  where 
  it 
  is 
  not 
  well 
  preserved. 
  

   It 
  is 
  found 
  in 
  the 
  Miocene 
  deposits 
  of 
  Bordeaux, 
  and 
  of 
  Dego 
  and 
  

   Cassinelle, 
  Piedmont. 
  

  

  Collections. 
  — 
  Mus. 
  Koyal 
  School 
  of 
  Mines 
  ; 
  Earl 
  of 
  Ducie's 
  ca- 
  

   binet. 
  

  

  16. 
  Echinolampas 
  hemisphjerictjs, 
  Lamarck. 
  

  

  Ch/£)eo:ster7iemisjohcericus,~Lamarck, 
  Anim.sans 
  Vert., 
  1816, 
  vol. 
  iii. 
  

   p. 
  293. 
  

  

  Clypeaster 
  hemisphcericus, 
  Grateloup, 
  Oursins 
  Eoss., 
  1836, 
  tab. 
  1. 
  

   fig. 
  7. 
  _ 
  

  

  Echinolampas 
  hemisphcericus, 
  Agassiz, 
  Prodrome 
  Mem. 
  Soc. 
  de 
  

   Neufchatel, 
  1835, 
  vol. 
  i. 
  p. 
  187. 
  

  

  Echinolampas 
  hemisphcericus, 
  Desor, 
  Synopsis 
  des 
  Echinides 
  Eoss., 
  

   1858, 
  p. 
  307. 
  

  

  Test 
  large, 
  discoidal, 
  slightly 
  rostrated 
  behind, 
  subcorneal; 
  ambu- 
  

   lacral 
  summit 
  excentral 
  ; 
  petaloid 
  ambulacra 
  unequal, 
  moderately 
  

   wide, 
  extending 
  over 
  two-thirds 
  of 
  the 
  upper 
  surface 
  ; 
  single 
  ambu- 
  

   lacrum 
  much 
  narrower 
  than 
  the 
  others 
  ; 
  poriferous 
  zones 
  narrow, 
  

   less 
  than 
  one-third 
  the 
  width 
  of 
  the 
  interporiferous 
  area 
  ; 
  under 
  

   surface 
  concave 
  ; 
  peristome 
  large, 
  excentral, 
  transversely 
  oval 
  op- 
  

   posite 
  the 
  disk, 
  surrounded 
  by 
  five 
  lobes, 
  between 
  which 
  are 
  five 
  

   alternating 
  narrow 
  phylloidal 
  expansions 
  with 
  numerous 
  pairs 
  of 
  

   pores 
  ; 
  vent 
  small, 
  inframarginal 
  ; 
  tubercles 
  small, 
  closely 
  set. 
  

  

  Dimensions. 
  — 
  A.ntero-posterior 
  diameter 
  4| 
  inches; 
  transverse 
  

   diameter 
  4J 
  inches 
  ; 
  height 
  ly^ 
  inch. 
  

  

  Description. 
  — 
  This 
  large 
  Echinolampas 
  seems 
  very 
  characteristic 
  

   of 
  the 
  Miocene 
  formation. 
  All 
  our 
  specimens 
  are 
  more 
  or 
  less 
  com- 
  

   pressed 
  ; 
  the 
  upper 
  surface 
  is 
  convex 
  or 
  subcorneal, 
  and 
  the 
  posterior 
  

   border 
  slightly 
  produced 
  ; 
  the 
  single 
  ambulacrum 
  is 
  much 
  narrower 
  

   than 
  the 
  pairs 
  ; 
  the 
  petaloid 
  ambulacra 
  extend 
  over 
  more 
  than 
  two- 
  

   thirds 
  of 
  the 
  dorsum, 
  and 
  are 
  slightly 
  raised 
  above 
  its 
  general 
  sur- 
  

   face 
  ; 
  the 
  poriferous 
  zones 
  are 
  narrow 
  and 
  composed 
  of 
  oblique 
  pairs 
  

   of 
  pores, 
  — 
  the 
  zones 
  are 
  scarcely 
  one-third 
  the 
  width 
  of 
  the 
  interpo- 
  

   riferous 
  area, 
  and 
  the 
  outer 
  row 
  consists 
  of 
  oblong, 
  the 
  inner 
  of 
  round 
  

   holes 
  with 
  faintly 
  marked 
  connecting 
  sulci. 
  The 
  apical 
  disk, 
  small 
  

   and 
  slightly 
  excentral, 
  occupies 
  the 
  ambulacral 
  summit; 
  the 
  spongy 
  

   madreporiform 
  body 
  envelopes 
  all 
  the 
  discal 
  elements, 
  so 
  that 
  the 
  

   genital 
  plates 
  are 
  only 
  visible 
  in 
  weathered 
  specimens. 
  The 
  base 
  

   is 
  concave 
  in 
  the 
  Maltese 
  specimens, 
  but 
  rather 
  convex 
  towards 
  the 
  

   border 
  in 
  a 
  specimen 
  from 
  the 
  Molasse 
  of 
  St. 
  Jean 
  de 
  Koyan 
  (Drome). 
  

  

  