﻿422 
  PROCEEDINGS 
  OP 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Julie 
  22, 
  

  

  and 
  fully 
  one-third 
  longer 
  ; 
  their 
  length 
  is 
  nearly 
  equal 
  to 
  one-fifth 
  

   of 
  that 
  of 
  the 
  entire 
  Fish 
  ; 
  they 
  are 
  also 
  more 
  curved 
  than 
  any 
  of 
  

   the 
  other 
  spines, 
  and, 
  as 
  remarked 
  by 
  Sir 
  Philip 
  Egerton, 
  the 
  cre- 
  

   nate 
  flutings 
  run 
  nearly 
  parallel 
  to 
  the 
  posterior 
  margin, 
  terminating, 
  

   as 
  the 
  spine 
  narrows, 
  in 
  the 
  anterior 
  margin 
  ; 
  they 
  are 
  so 
  firmly 
  

   attached 
  to 
  the 
  pectoral 
  arches 
  that 
  they 
  appear 
  to 
  be 
  anchylosed 
  

   rather 
  than 
  articulated 
  with 
  those 
  bones, 
  which 
  are 
  strong, 
  curved, 
  

   and 
  pointed. 
  As 
  in 
  Climatius 
  scutiger, 
  the 
  space 
  between 
  the 
  pecto- 
  

   ral 
  and 
  ventral 
  spines 
  is 
  occupied 
  by 
  several 
  pairs 
  of 
  very 
  short, 
  

   stout 
  dermal 
  spines, 
  having, 
  like 
  all 
  the 
  other 
  spines, 
  crenate 
  

   ridges. 
  I 
  cannot 
  positively 
  state 
  the 
  number 
  of 
  these, 
  but 
  there 
  

   appear 
  to 
  have 
  been 
  five 
  pairs. 
  Vestiges 
  of 
  the 
  dorsal, 
  pectoral, 
  and 
  

   anal 
  fins 
  are 
  preserved 
  in 
  one 
  or 
  other 
  of 
  my 
  specimens 
  ; 
  they 
  had 
  

   evidently 
  been 
  membranous, 
  covered 
  with 
  parallel 
  rows 
  of 
  very 
  

   minute 
  scales. 
  The 
  scales 
  are 
  proportionally 
  larger 
  than 
  in 
  most 
  of 
  the 
  

   Forfarshire 
  Acanthodians 
  ; 
  they 
  are 
  rhomboidal, 
  and, 
  with 
  the 
  excep- 
  

   tion 
  of 
  a 
  few 
  rows 
  along 
  the 
  dorsal 
  ridge, 
  which 
  run 
  longitudinally, 
  

   are 
  arranged 
  in 
  oblique 
  rows 
  across 
  the 
  body, 
  and 
  decrease 
  in 
  size 
  

   from 
  the 
  shoulder 
  towards 
  the 
  tail. 
  Their 
  outer 
  surface 
  is 
  smooth 
  

   and 
  shining, 
  and 
  but 
  little 
  raised 
  in 
  the 
  centre 
  : 
  the 
  sculpturing 
  

   of 
  the 
  inner 
  surface 
  is 
  very 
  peculiar 
  ; 
  this 
  surface 
  in 
  each 
  scale 
  

   is 
  covered 
  by 
  minute 
  tubercles, 
  generally 
  five 
  in 
  number, 
  

   arranged 
  along 
  the 
  diagonals 
  ; 
  each 
  tubercle 
  is 
  distinctly 
  striated, 
  

   having 
  commonly 
  two 
  or 
  three 
  distinct 
  stria? 
  radiating 
  towards 
  

   the 
  posterior 
  angle. 
  The 
  head 
  in 
  all 
  my 
  specimens 
  is 
  imperfectly 
  

   preserved, 
  but 
  appears 
  to 
  be 
  covered 
  by 
  thick, 
  closely 
  set, 
  seemingly 
  

   hexagonal 
  scales, 
  rather 
  larger 
  than 
  those 
  of 
  the 
  body, 
  having 
  the 
  

   outer 
  surface 
  coarsely 
  granular, 
  and 
  the 
  inner 
  quite 
  covered 
  by 
  

   minute 
  sculptured 
  tubercles. 
  The 
  branchial 
  apparatus 
  consists 
  of 
  

   exposed 
  arches 
  extending 
  from 
  the 
  lower 
  side 
  of 
  the 
  head 
  down- 
  

   wards 
  on 
  the 
  thorax 
  ; 
  in 
  only 
  one 
  specimen 
  is 
  this 
  shown, 
  and 
  in 
  it 
  

   very 
  indistinctly. 
  

  

  Climatius 
  uncinatus, 
  Egerton. 
  

  

  Head 
  broad, 
  short, 
  rounded, 
  depressed 
  ; 
  spines 
  with 
  smooth 
  or 
  

   crenate 
  ridges 
  ; 
  anterior 
  dorsal 
  stout, 
  straight, 
  ridges 
  crenate 
  ; 
  pec- 
  

   torals 
  slender, 
  curved, 
  toothed 
  posteriorly, 
  ridges 
  crenate. 
  At 
  least 
  

   five 
  pairs 
  of 
  dermal 
  intermediate 
  spines. 
  

  

  This 
  species 
  is 
  so 
  named 
  by 
  Sir 
  Philip 
  Egerton 
  from 
  its 
  peculiar 
  

   pectoral 
  spine. 
  On 
  comparing 
  this 
  spine 
  with 
  those 
  figured 
  by 
  

   Agassiz 
  *, 
  and 
  named 
  Homacantlms 
  areuatus, 
  especially 
  figure 
  2, 
  and 
  

   that 
  figured 
  and 
  named 
  by 
  Eichwald 
  Homacanthus 
  c/racilisf, 
  the 
  

   resemblance 
  is 
  so 
  marked 
  that 
  I 
  cannot 
  doubt 
  that 
  they 
  also 
  are 
  the 
  

   pectoral 
  spines 
  of 
  Fishes 
  belonging 
  to 
  this 
  genus. 
  They 
  are, 
  how- 
  

   ever, 
  described 
  both 
  by 
  Agassiz 
  and 
  Eichwald 
  as 
  having 
  the 
  ridges 
  

   smooth, 
  while 
  in 
  the 
  Climatius 
  uncinatus 
  they 
  are 
  crenate, 
  as 
  is 
  

   very 
  clearly 
  shown 
  by 
  a 
  specimen 
  in 
  Mr. 
  Mitchell's 
  collection. 
  

  

  This 
  is 
  the 
  rarest 
  of 
  such 
  of 
  our 
  Forfarshire 
  Fishes 
  as 
  have 
  

  

  * 
  ' 
  Vieux 
  Gres 
  Rouge,' 
  pi. 
  xxxiii. 
  figs. 
  1, 
  2, 
  3. 
  

   t 
  ' 
  Lethsea 
  Rossica,' 
  pi. 
  lv. 
  fig. 
  9. 
  

  

  