﻿18G4.] 
  P0WRIE 
  — 
  FORFARSHIRE 
  FOSSILS. 
  417 
  

  

  to 
  have 
  no 
  connexion 
  with 
  the 
  egg-packets 
  ; 
  indeed, 
  it 
  appears 
  to 
  

   be 
  on 
  a 
  distinct 
  thin 
  overlying 
  film 
  of 
  stone. 
  It 
  is 
  by 
  no 
  means 
  

   unlikely, 
  as 
  noticed 
  in 
  the 
  Monograph, 
  that 
  the 
  Parka 
  in 
  some 
  

   cases 
  had 
  been 
  pedunculated, 
  and 
  in 
  this 
  way 
  attached 
  to 
  the 
  parent 
  

   animal, 
  as 
  specimens 
  are 
  not 
  uncommon 
  showing 
  the 
  eggs 
  spread 
  

   out 
  on 
  a 
  seeming 
  membrane. 
  At 
  the 
  same 
  time 
  it 
  must 
  be 
  allowed 
  

   that 
  Parka 
  decipiens 
  has 
  never 
  yet 
  been 
  found 
  undoubtedly 
  attached 
  

   to 
  any 
  of 
  these 
  animals, 
  although 
  frequently 
  in 
  close 
  proximity 
  on 
  

   the 
  same 
  layer 
  of 
  shale. 
  

  

  PISCES. 
  

  

  Adopting 
  the 
  classification 
  of 
  Professor 
  Huxley 
  in 
  his 
  Introductory 
  

   Essay 
  to 
  the 
  Tenth 
  Decade 
  of 
  Plates 
  of 
  Organic 
  Remains, 
  published 
  

   in 
  the 
  Memoirs 
  of 
  the 
  Geological 
  Survey, 
  all 
  the 
  Fish-remains 
  suf- 
  

   ficiently 
  entire 
  for 
  identification 
  found 
  in 
  the 
  sandstones 
  and 
  shales 
  

   of 
  Forfarshire 
  belong 
  to 
  the 
  two 
  families 
  Acanthodidj3 
  and 
  Cepha- 
  

   laspidje. 
  

  

  Family 
  ACANTHODID^E, 
  

  

  Our 
  Forfarshire 
  rocks 
  have 
  now 
  yielded 
  five 
  genera 
  belonging 
  to 
  

   this 
  family, 
  AcantJiodes, 
  IscJinacanthus, 
  Clematius, 
  Pareccus, 
  and 
  

   EutJiacantJius. 
  With 
  the 
  exception 
  of 
  AcantJiodes, 
  which 
  extends 
  

   upwards 
  even 
  into 
  Permian 
  rocks, 
  these 
  genera 
  are 
  all 
  peculiar 
  to 
  

   this 
  formation. 
  

  

  My 
  leisure 
  hours 
  having 
  now 
  for 
  some 
  years 
  been 
  in 
  a 
  great 
  

   measure 
  devoted 
  to 
  searching 
  for 
  and 
  studying 
  the 
  peculiarities 
  of 
  

   our 
  Forfarshire 
  fishes, 
  I 
  am 
  necessarily 
  much 
  better 
  acquainted 
  

   with 
  the 
  characteristics 
  of 
  this 
  family, 
  as 
  exhibited 
  in 
  the 
  compara- 
  

   tively 
  little-known 
  genera 
  belonging 
  to 
  these 
  rocks, 
  than 
  with 
  those 
  

   found 
  in 
  the 
  upper 
  divisions 
  of 
  the 
  Old 
  Red 
  and 
  still 
  more 
  modern 
  

   formations. 
  I 
  shall, 
  therefore, 
  in 
  the 
  following 
  remarks, 
  confine 
  

   myself 
  to 
  the 
  peculiarities 
  of 
  the 
  family 
  as 
  exhibited 
  in 
  these 
  genera. 
  

   Besides, 
  the 
  genera 
  belonging 
  to 
  the 
  newer 
  formations 
  are 
  mostly 
  

   well 
  known, 
  and 
  have 
  all 
  been 
  already 
  carefully 
  studied 
  and 
  ably 
  

   wrought 
  out 
  by 
  much 
  more 
  competent 
  observers. 
  

  

  In 
  the 
  essay 
  referred 
  to, 
  Professor 
  Huxley 
  observes, 
  that 
  although 
  

   the 
  family 
  Acanthodidae 
  are 
  generally 
  ranked 
  amongst 
  the 
  Ganoids, 
  

   several 
  considerations 
  there 
  given 
  lead 
  him 
  to 
  suspect 
  that 
  they 
  

   may 
  be 
  Elasmobranchs. 
  In 
  many 
  respects 
  their 
  characteristics 
  

   appear 
  to 
  me 
  to 
  be 
  of 
  an 
  intermediate 
  nature. 
  

  

  Of 
  the 
  dorsal 
  spines 
  he 
  remarks 
  that 
  their 
  form 
  and 
  mode 
  of 
  im- 
  

   plantation 
  are 
  similar 
  to 
  those 
  of 
  the 
  Elasmobranchs, 
  but 
  that 
  the 
  

   implanted 
  portion 
  is 
  less 
  different 
  from 
  the 
  rest 
  of 
  the 
  spine 
  than 
  

   in 
  that 
  order. 
  It 
  is 
  rare 
  to 
  find 
  spines 
  sufficiently 
  preserved 
  to 
  

   show 
  the 
  difference 
  ; 
  but 
  the 
  better 
  the 
  state 
  of 
  preservation, 
  the 
  

   more 
  marked 
  the 
  difference 
  becomes. 
  The 
  exposed 
  portion 
  appears 
  

   to 
  have 
  been 
  strongly 
  coated 
  by 
  a 
  very 
  durable 
  substance 
  resembling 
  

   enamel, 
  which 
  in 
  the 
  implanted 
  portion 
  had 
  been 
  either 
  wanting 
  or 
  

   of 
  a 
  more 
  perishable 
  quality 
  ; 
  hence 
  the 
  spines, 
  when 
  found, 
  have 
  

  

  