﻿w 
  rORH 
  EE 
  mi 
  si.i 
  \i 
  

  

  e\e\ 
  ;ii 
  inn 
  n}' 
  i 
  he 
  concentric 
  lim-s. 
  is 
  

   be 
  upper 
  Devonic 
  (Cleveland 
  Bhales), 
  while 
  Tup- 
  

   r 
  i 
  ii 
  the 
  middle 
  L"\\< 
  p 
  Siluric. 
  

  

  T!i. 
  qual 
  Btructnre 
  al 
  such 
  widely 
  

  

  ivr 
  only 
  to 
  strengthen 
  the 
  belief 
  in 
  their 
  

   _ 
  a 
  differenl 
  and 
  persistent 
  type 
  <>t* 
  crustacean 
  struc- 
  

   tin 
  

  

  Pol 
  1 
  i 
  c 
  i 
  pes 
  Bilnricus 
  Bp. 
  n. 
  (pi. 
  2, 
  fig. 
  16-24). 
  

   In 
  the 
  rtica 
  Bhales 
  of 
  Green 
  Island 
  and 
  Mechanicsville 
  occur 
  

   vai 
  shaped 
  valves 
  in 
  considerable 
  number, 
  which 
  l>.\ 
  their 
  

  

  peculiar 
  shapes, 
  the 
  arrangement 
  of 
  their 
  growth 
  lines 
  and 
  their 
  

   shell 
  structure, 
  differ 
  from 
  the 
  valves 
  of 
  all 
  mollusks 
  associa 
  

   with 
  them 
  in 
  the 
  same 
  rock. 
  A 
  suggestion 
  of 
  Dr 
  dark. 
  

   their 
  possible 
  crustacean 
  nature 
  led 
  to 
  the 
  astonishing 
  discovery 
  

   thai 
  they 
  all 
  find 
  their 
  homologues 
  in 
  parts 
  of 
  the 
  capitula 
  of 
  

   the 
  pedunculate 
  cirriped 
  genera 
  Bcalpellum 
  and 
  Pol 
  li- 
  

   cipes, 
  notably 
  of 
  the 
  latter. 
  On 
  this 
  accounl 
  the 
  various 
  

   valves 
  have 
  been 
  united 
  under 
  the 
  caption, 
  Pollicipfi 
  e 
  

   siluricus, 
  in 
  full 
  consciousness 
  oi 
  the 
  enormous 
  gap 
  exist- 
  

   •a 
  the 
  appearance 
  of 
  this 
  Lower 
  Biluric 
  type 
  and 
  the 
  

   next 
  Upper 
  Triassic 
  (Bhaetic) 
  representatives 
  of 
  these 
  genera, 
  

   ae 
  case 
  of 
  the 
  related 
  Balanidae 
  mighl 
  be 
  cited 
  

   in 
  Bupport. 
  Charles 
  Darwin, 
  in 
  his 
  classic 
  memoir 
  on 
  the 
  fossil 
  

   stated 
  thai 
  in 
  the 
  sessile 
  Cirripedia, 
  or 
  Balanidae, 
  

   the 
  Q< 
  \ 
  evidence 
  of 
  tfceir 
  not 
  being 
  found 
  in 
  primary 
  or 
  

  

  formations 
  is 
  of 
  considerable 
  value, 
  considering 
  their 
  

   it 
  Dumber 
  where 
  they 
  appear, 
  their 
  Btrong 
  shells, 
  etc.; 
  and 
  

   ni'-anw 
  hile, 
  undoubted 
  Paleozoic 
  genera 
  nf 
  Balanidae 
  (Pro- 
  

   lan 
  us, 
  Palaeocreusia) 
  have 
  beeu 
  found, 
  leaving 
  

   i 
  from 
  the 
  Devonic 
  to 
  the 
  Cretaceous 
  without 
  

   e* 
  Qtativea 
  of 
  this 
  family. 
  Ii 
  is 
  an 
  interesting 
  query, 
  

   : 
  **ere 
  the 
  conditions 
  of 
  marine 
  life 
  thai 
  suppressed 
  the 
  Lepa- 
  

   didac 
  ;ind 
  I'.alanidar, 
  wldrli 
  mday 
  till 
  tin- 
  n 
  .-.-aiis 
  with 
  BUCh 
  \. 
  

  

  Lepadldae, 
  or 
  pedunculated 
  cirripedes 
  of 
  

   Palaeont 
  boc. 
  1861 
  

  

  