﻿OF 
  THE 
  MORAY 
  FIRTH 
  AREA. 
  

  

  245 
  

  

  Family 
  ACANTHODIDiE. 
  

  

  Genus 
  MESA 
  CA 
  NTH 
  U 
  S, 
  Traquair, 
  1888. 
  

   Mesacanthus 
  pusillus, 
  Agassiz, 
  1844. 
  

   Syn. 
  A 
  canthodes 
  pusillus, 
  Ag. 
  et 
  cet. 
  auct. 
  

  

  In 
  1888 
  (44) 
  I 
  instituted 
  the 
  genus 
  Mesacanthus 
  for 
  the 
  Acanthodes 
  

   Mitchelli 
  of 
  Egerton 
  from 
  the 
  Forfarshire 
  beds, 
  on 
  account 
  of 
  

   the 
  presence 
  of 
  a 
  pair 
  of 
  small 
  spines 
  intermediate 
  between 
  the 
  

   pectorals 
  and 
  ventrals 
  in 
  that 
  species. 
  These 
  intermediate 
  spines 
  

   have 
  not 
  been 
  as 
  yet 
  detected 
  in 
  pusillus, 
  but 
  I 
  have 
  placed 
  it 
  

   along 
  with 
  Mitchelli 
  on 
  account 
  of 
  its 
  great 
  similarity 
  in 
  form, 
  

   while 
  the 
  very 
  small 
  size 
  and 
  imperfect 
  preservation 
  of 
  the 
  speci- 
  

   men 
  renders 
  it 
  difficult 
  to 
  come 
  to 
  a 
  definite 
  conclusion 
  as 
  to 
  the 
  

   entire 
  absence 
  of 
  the 
  spines 
  in 
  question. 
  

  

  Cromarty, 
  Lethen 
  Bar, 
  and 
  Tynet 
  Burn, 
  but 
  not 
  abundant. 
  

  

  Genus 
  C 
  HEIR 
  A 
  CA 
  NTH 
  US, 
  Agassiz. 
  

   Cheiracanthus 
  M 
  urchisoni, 
  Agassiz, 
  1835. 
  

  

  Syn. 
  Ch. 
  minor, 
  Ag. 
  ; 
  Ch. 
  microlepidotus, 
  Ag. 
  j 
  Ch. 
  lateralis, 
  M'Coy 
  ; 
  

   Ch. 
  pulverulentus, 
  M'Coy. 
  

  

  (Restored 
  figure, 
  PI. 
  ii. 
  fig. 
  2.) 
  / 
  

   Agassiz 
  distinguished 
  the 
  specimens 
  from 
  Lethen 
  from 
  those 
  occur- 
  

   ring 
  at 
  Gamrie, 
  giving 
  the 
  name 
  of 
  microlepidotus 
  to 
  the 
  former; 
  but 
  

   there 
  is 
  no 
  difference 
  save 
  in 
  mode 
  of 
  preservation. 
  Nor 
  can 
  

   Ch. 
  minor 
  Ag., 
  lateralis 
  M'Coy, 
  and 
  pndverulentus 
  M'Coy, 
  all 
  from 
  

   Orkney, 
  be 
  distinguished 
  from 
  the 
  Murchisoni 
  of 
  the 
  Moray 
  Firth 
  

   beds. 
  The 
  same 
  species 
  occurs 
  also 
  at 
  Achanarras. 
  

  

  Common 
  at 
  Cromarty, 
  Lethen, 
  Clune, 
  and 
  Gamrie 
  ; 
  less 
  so 
  at 
  

   Tynet 
  Burn. 
  

  

  Cheiracanthus 
  latus, 
  Egerton, 
  1861. 
  

  

  Common 
  at 
  Tynet 
  Burn, 
  and 
  also 
  occurring 
  at 
  Cromarty, 
  Lethen, 
  and 
  

   Gamrie. 
  

  

  Sub-class 
  OSTRACODERML 
  

   Order 
  ANTIARCHA. 
  

   Family 
  ASTEROLEPIDiE. 
  

  

  Genus 
  PTERICHTHYS, 
  Agassiz. 
  

   Pterichthys 
  Milleri, 
  Agassiz, 
  1841. 
  

   Syn. 
  Pt.latus, 
  Ag.; 
  PL 
  lestudinarius, 
  Ag.; 
  Pt.cornutus, 
  Ag.; 
  Pt.latus, 
  Egert. 
  

   (Restored 
  figures, 
  PI. 
  i. 
  figs. 
  1, 
  2, 
  3.) 
  

   Common 
  at 
  Cromarty, 
  Lethen, 
  and 
  Gamrie 
  ; 
  found 
  also 
  at 
  Edderton 
  

  

  