﻿234 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Mar. 
  23, 
  

  

  than 
  the 
  Lower 
  Llandeilo 
  Flags 
  and 
  Caradoc 
  Sandstone, 
  with 
  one, 
  

   perhaps 
  doubtful, 
  exception 
  hereafter 
  mentioned. 
  

  

  I 
  beg 
  leave 
  to 
  offer 
  an 
  amended 
  description 
  of 
  the 
  large 
  Para- 
  

   doockles 
  ; 
  for 
  there 
  are 
  now 
  the 
  means, 
  through 
  nearly 
  a 
  hundred 
  

   specimens, 
  of 
  making 
  it 
  complete. 
  These 
  better 
  specimens 
  show 
  the 
  

   eye 
  to 
  have 
  been 
  more 
  forward 
  than 
  was 
  previously 
  supposed, 
  and 
  

   supply 
  the 
  great 
  head-spines, 
  the 
  hinder 
  thoracic 
  rings, 
  and 
  the 
  tail, 
  

   which 
  is 
  of 
  a 
  very 
  remarkable 
  structure, 
  and 
  quite 
  unlike 
  that 
  of 
  

   any 
  other 
  species 
  of 
  the 
  genus. 
  

  

  Fortunately 
  I 
  had, 
  in 
  the 
  figure, 
  distinguished 
  those 
  parts 
  which 
  

   were 
  known 
  from 
  those 
  that 
  were 
  hypothetical, 
  and 
  therefore 
  there 
  

   is 
  little 
  to 
  alter, 
  though 
  much 
  to 
  add. 
  I 
  can, 
  however, 
  see 
  no 
  confir- 
  

   mation 
  of 
  the 
  two 
  obscure 
  anterior 
  furrows 
  to 
  the 
  glabella, 
  and 
  omit 
  

   them 
  accordingly. 
  

  

  Paradoxides 
  Davidis, 
  Salter, 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xix. 
  

   p. 
  275. 
  PI. 
  XIII. 
  figs. 
  1-3. 
  

  

  Spec. 
  Char. 
  — 
  P. 
  sesquipedalis 
  et 
  ultra, 
  maximus, 
  glabella 
  parum 
  

   clavatd, 
  gents 
  latiore, 
  sulcis 
  duobus 
  solum 
  perfectis, 
  reliquis 
  obso- 
  

   letis. 
  Oculi 
  antrorsum 
  positi. 
  Thorax 
  art 
  iculis 
  18, 
  axe 
  lato. 
  

   Pleural 
  subrectm, 
  apicibus 
  recurvis, 
  anticis 
  brevisshnis 
  abrupte 
  

   Jlexis, 
  medianis 
  longioribus 
  arcuatis, 
  postremis 
  valde 
  retrorsum 
  

   jiexis, 
  fere 
  par 
  •allelis, 
  ultimis 
  longissimis. 
  Cauda 
  mira, 
  parte 
  

   centrali 
  oblonga 
  truncata, 
  gladiis 
  lateralibus 
  longissimis. 
  Caudal 
  

   axis 
  obscurus, 
  2-3-annulatus. 
  

   Of 
  the 
  head 
  we 
  have 
  now 
  many 
  specimens, 
  and 
  some 
  of 
  the 
  frag- 
  

   ments 
  betoken 
  a 
  fossil 
  not 
  less 
  than 
  16 
  or 
  18 
  inches 
  long. 
  One 
  or 
  

   two 
  heads 
  are 
  perfect, 
  and 
  show 
  that 
  it 
  was 
  semicircular, 
  with 
  very 
  

   large, 
  thick, 
  cylindrical, 
  and 
  tolerably 
  straight 
  spines. 
  The 
  glabella 
  

   is 
  rather 
  long, 
  reaching 
  and 
  overhanging 
  the 
  front 
  margin, 
  broader, 
  

   but 
  not 
  suddenly 
  so, 
  in 
  front, 
  half 
  its 
  length 
  being 
  occupied 
  by 
  the 
  

   great 
  front 
  lobe. 
  

  

  There 
  are 
  obscure 
  traces 
  in 
  some 
  specimens 
  of 
  short 
  anterior 
  fur- 
  

   rows, 
  but 
  I 
  cannot 
  be 
  sure 
  of 
  more 
  than 
  the 
  two 
  complete 
  posterior 
  

   ones, 
  which 
  bend 
  backwards 
  in 
  the 
  middle, 
  and 
  are 
  equally 
  strong 
  

   with 
  the 
  neck-furrow. 
  The 
  eye 
  is 
  far 
  forward, 
  in 
  advance 
  even 
  of 
  

   the 
  second 
  or 
  upper 
  glabella-furrow 
  ; 
  it 
  is 
  near 
  the 
  glabella 
  — 
  not 
  

   half 
  its 
  length 
  distant 
  from 
  it. 
  

  

  The 
  cheek 
  is 
  coarsely 
  granular, 
  except 
  towards 
  the 
  outer 
  angle, 
  

   and 
  abruptly 
  contracted 
  at 
  the 
  base 
  of 
  the 
  great 
  cylindrical 
  spine. 
  

  

  The 
  labrum 
  is 
  expanded 
  at 
  the 
  base, 
  and 
  has 
  a 
  truncated 
  end, 
  

   with 
  subspinous 
  lateral 
  angles. 
  It 
  is, 
  as 
  usual, 
  separated 
  by 
  scarcely 
  

   any 
  suture 
  from 
  the 
  hypostome, 
  or 
  rather 
  it 
  is 
  connate 
  with 
  it 
  (fig. 
  1 
  a). 
  

   I 
  cannot 
  count 
  more 
  than 
  eighteen 
  rings 
  to 
  the 
  body, 
  and 
  believe 
  

   this 
  to 
  be 
  the 
  full 
  number. 
  The 
  axis 
  is 
  very 
  wide 
  (in 
  the 
  largest 
  

   specimen 
  \\ 
  inch) 
  and 
  convex, 
  fully 
  as 
  wide 
  in 
  front 
  as 
  the 
  pleurae, 
  

   spine 
  included, 
  and 
  so 
  for 
  the 
  eight 
  or 
  nine 
  front 
  segments. 
  The 
  apex 
  

   of 
  each 
  pleura 
  in 
  these 
  is 
  abruptly 
  turned 
  back, 
  with 
  a 
  short 
  sharp 
  

   mucro 
  ; 
  and 
  there 
  is 
  no 
  enlargement 
  of 
  the 
  second 
  or 
  third 
  pleura 
  — 
  

   a 
  character 
  of 
  importance 
  in 
  this 
  genus. 
  All 
  have 
  a 
  deep 
  groove, 
  

  

  