﻿238 
  

  

  3IE. 
  E. 
  LTDEK.KER 
  OX 
  REMAINS 
  OF 
  EOCEXE 
  AXD 
  iTESOZOIC 
  

  

  two 
  forms 
  consists 
  in 
  the 
  much 
  narrower 
  costal 
  shields 
  of 
  P. 
  sanctce- 
  

   verence, 
  or, 
  in 
  other 
  words, 
  the 
  wider 
  vertebrals. 
  

  

  Fig, 
  4. 
  — 
  Restoration 
  of 
  the 
  Carapace 
  of 
  Plesiochelys 
  Brodiei 
  ; 
  from 
  

   the 
  Wealden 
  of 
  the 
  Isle 
  of 
  Wight. 
  J, 
  

  

  "With 
  the 
  exception 
  of 
  the 
  marginals 
  the 
  restoration 
  is 
  entirely 
  based 
  on 
  the 
  

   actual 
  remains 
  preserved. 
  

  

  The 
  letters 
  n 
  1 
  to 
  n 
  8 
  indicate 
  the 
  neural, 
  and 
  c 
  1 
  to 
  o 
  8 
  the 
  costal 
  bones. 
  

  

  Although 
  I 
  am 
  aware 
  that 
  the 
  size 
  and 
  contour 
  of 
  the 
  epidermal 
  

   shields 
  is 
  liable 
  to 
  a 
  considerable 
  variation 
  among 
  existing 
  Chelo- 
  

   nians, 
  and 
  affords 
  a 
  somewhat 
  unsatisfactory 
  basis 
  of 
  specific 
  dis- 
  

   tinction, 
  yet, 
  taking 
  into 
  account 
  the 
  constancy 
  in 
  the 
  contour 
  of 
  

   the 
  shields 
  of 
  the 
  specimens 
  described 
  by 
  Eiitimeyer, 
  and 
  the 
  wide 
  

   difference 
  in 
  the 
  age 
  of 
  the 
  geological 
  horizons 
  of 
  the 
  Swiss 
  and 
  

   English 
  forms, 
  I 
  am 
  disposed 
  in 
  this 
  instance 
  to 
  regard 
  these 
  features 
  

   as 
  of 
  specific 
  value. 
  The 
  English 
  form 
  may 
  be 
  designated, 
  after 
  the 
  

   owner 
  of 
  the 
  type 
  specimen, 
  Plesiochelys 
  Brodiei. 
  

  

  On 
  further 
  comparison 
  of 
  the 
  second 
  Wealden 
  shell 
  of 
  a 
  Plesio- 
  

   chelys 
  (B.M. 
  No. 
  28976), 
  I 
  find 
  that 
  this 
  specimen 
  is 
  distinguished 
  

   from 
  P. 
  sanctce-verence 
  by 
  its 
  narrower 
  costal 
  shields, 
  and 
  I 
  accordingly 
  

  

  