﻿ANNIVERSARY 
  ADDRESS 
  OF 
  THE 
  PRESIDENT. 
  

  

  149 
  

  

  In 
  the 
  Lower 
  Lias 
  : 
  — 
  

  

  

  

  Acrosalenia 
  . 
  . 
  possesses 
  

  

  2 
  species. 
  

  

  Apiocrinus 
  . 
  . 
  „ 
  

  

  1 
  

  

  11 
  

  

  Cidaris 
  „ 
  

  

  1 
  

  

  11 
  

  

  Extracrinus 
  . 
  . 
  „ 
  

  

  1 
  

  

  » 
  

  

  Hemipedina 
  . 
  . 
  ,, 
  

  

  1 
  

  

  11 
  

  

  Ophiolepis 
  . 
  . 
  „ 
  

  

  1 
  

  

  11 
  

  

  Pentacrinus 
  . 
  . 
  „ 
  

  

  2 
  

  

  11 
  

  

  Plicatocrinus 
  . 
  „ 
  

  

  1 
  

  

  11 
  

  

  Plumaster 
  . 
  . 
  „ 
  

  

  1 
  

  

  11 
  

  

  Pseudodiadema 
  ,, 
  

  

  1 
  

  

  11 
  

  

  12 
  

  

  The 
  Middle 
  Lias 
  presents 
  similar 
  results 
  : 
  — 
  

  

  Acroura 
  .... 
  

   Aspidura 
  .... 
  

   Astropecten 
  . 
  . 
  

   Cidaris 
  

  

  yields 
  

  

  •>■) 
  

   n 
  

   n 
  

  

  1 
  

  

  1 
  

  

  2 
  

   1 
  

  

  Extracrinus 
  . 
  . 
  

  

  ■>■) 
  

  

  1 
  

  

  Hemipedina 
  . 
  . 
  

   Ophiolepis 
  . 
  . 
  

   Pentacrinus 
  . 
  . 
  

  

  11 
  

   •a 
  

  

  11 
  

  

  1 
  

   1 
  

  

  9 
  

  

  Plumaster 
  . 
  . 
  . 
  

  

  11 
  

  

  1 
  

  

  Pseudodiadema 
  

  

  11 
  

  

  1 
  

  

  Rhabdocrinus 
  . 
  

  

  11 
  

  

  1 
  

  

  Tropidaster 
  . 
  . 
  

   Uraster 
  .... 
  

  

  11 
  

   )1 
  

  

  1 
  

   2 
  

  

  Ophioderma 
  . 
  . 
  

  

  11 
  

  

  5 
  

  

  species. 
  

  

  28 
  „ 
  

   The 
  Upper 
  Lias 
  possesses 
  a 
  much 
  smaller 
  fauna, 
  and 
  no 
  species 
  

   passes 
  from 
  either 
  of 
  the 
  three 
  divisions 
  of 
  the 
  Lias 
  to 
  any 
  higher 
  

   horizon 
  ; 
  the 
  succeeding 
  beds 
  of 
  the 
  Inferior 
  Oolite 
  contain 
  33 
  

   species, 
  all 
  totally 
  new. 
  The 
  Upper 
  Lias 
  genera 
  and 
  their 
  specific 
  

   value 
  is 
  expressed 
  as 
  before 
  

  

  has 
  yielded 
  1 
  species. 
  

  

  Acrosalenia 
  

   Cidaris 
  .... 
  

   Diplocidaris 
  

   Hemipedina 
  

   Ophioderma 
  

   Pentacrinus 
  

   Pseudodiadema 
  

  

  1 
  

   1 
  

   1 
  

   6 
  

   2 
  

  

  14 
  

  

  rTo 
  Palaeozoic 
  form 
  lived 
  on 
  into 
  the 
  sea 
  of 
  the 
  Lias. 
  The 
  one 
  

   single 
  genus 
  known 
  in 
  the 
  Permian 
  rocks, 
  Archceocidaris, 
  modified 
  

   through 
  descent 
  from 
  the 
  Carboniferous 
  Limestone 
  and 
  Permian 
  

   rocks, 
  may 
  perhaps 
  have 
  been 
  the 
  progenitor 
  of 
  the 
  Cidaridae 
  of 
  the 
  

   Lias; 
  no 
  other 
  type 
  of 
  the 
  Echinoidca 
  has 
  been 
  transmitted. 
  The 
  

  

  