﻿1863.] 
  EGEBT0N 
  ICHTHYOLITES 
  FEOM 
  NEW 
  SOrTH 
  WALES. 
  3 
  

  

  the 
  middle 
  of 
  the 
  abdominal 
  line. 
  The 
  dorsal 
  fin 
  is 
  inserted 
  rather 
  

   nearer 
  to 
  the 
  tail 
  than 
  are 
  the 
  ventrals. 
  The 
  dislocated 
  fin-rays 
  

   before 
  alluded 
  to 
  in 
  the 
  specimen 
  from 
  Chapel 
  Hill 
  may 
  have 
  be- 
  

   longed 
  to 
  the 
  anal 
  fin. 
  All 
  evidence 
  of 
  the 
  form 
  of 
  the 
  tail 
  is 
  defi- 
  

   cient. 
  On 
  comparing 
  these 
  characters 
  with 
  those 
  of 
  known 
  genera, 
  

   there 
  is 
  little 
  doubt 
  that 
  the 
  affinities 
  to 
  Acrolepis 
  are 
  very 
  promi- 
  

   nent. 
  The 
  position 
  of 
  the 
  several 
  fins, 
  the 
  form 
  and 
  ornamentation 
  

   of 
  the 
  scales, 
  and 
  the 
  general 
  figure 
  of 
  the 
  body 
  are 
  all 
  points 
  of 
  re- 
  

   semblance 
  with 
  that 
  genus 
  ; 
  at 
  the 
  same 
  time, 
  in 
  the 
  absence 
  of 
  more 
  

   conclusive 
  evidence 
  as 
  to 
  many 
  other 
  essential 
  points, 
  I 
  must 
  hesi- 
  

   tate 
  to 
  pronounce 
  any 
  opinion 
  as 
  to 
  the 
  identity 
  of 
  the 
  Australian 
  

   with 
  the 
  European 
  genus. 
  I 
  would 
  rather 
  suggest 
  a 
  provisional 
  

   name, 
  and 
  designate 
  this 
  Fish 
  as 
  Myriolepis 
  Clarkei 
  until 
  more 
  satis- 
  

   factory 
  materials 
  shall 
  come 
  to 
  light, 
  to 
  clear 
  up 
  the 
  doubtful 
  points 
  

   in 
  the 
  anatomy 
  and 
  natural 
  affinities 
  of 
  this 
  interesting 
  extinct 
  Fish. 
  

  

  The 
  other 
  specimen 
  sent 
  by 
  Mr. 
  Clarke 
  is 
  a 
  lump 
  of 
  indurated 
  

   grey 
  shale, 
  containing 
  the 
  head 
  and 
  anterior 
  two 
  -thirds 
  of 
  a 
  

   Pycnodont 
  Fish 
  very 
  much 
  resembling 
  the 
  genus 
  Platysomus. 
  The 
  

   scales 
  are 
  perhaps 
  narrower 
  in 
  antero-posterior 
  dimensions 
  than 
  in 
  

   those 
  Platysomi 
  hitherto 
  described, 
  and 
  the 
  articulating 
  rib 
  on 
  

   the 
  inner 
  surface 
  of 
  the 
  scales 
  is 
  decidedly 
  stronger. 
  These 
  pecu- 
  

   liarities 
  would 
  scarcely 
  indicate 
  more 
  than 
  specific 
  characters. 
  A 
  

   photograph, 
  however, 
  of 
  a 
  second 
  specimen, 
  evidently 
  of 
  the 
  same 
  

   species 
  and 
  found 
  in 
  the 
  same 
  locality, 
  shows 
  the 
  posterior 
  portion 
  

   of 
  the 
  Fish 
  (deficient 
  in 
  the 
  other), 
  and 
  here 
  we 
  find 
  some 
  striking 
  

   discrepancies 
  from 
  the 
  corresponding 
  parts 
  in 
  the 
  Platysomi. 
  In 
  the 
  

   last-named 
  genus 
  the 
  dorsal 
  fin 
  commences 
  at 
  the 
  culminating 
  point 
  

   of 
  the 
  dorsal 
  ridge, 
  and 
  extends 
  thence 
  to 
  the 
  upper 
  lobe 
  of 
  the 
  cau- 
  

   dal 
  fin, 
  the 
  component 
  rays 
  diminishing 
  very 
  gradually 
  in 
  length 
  

   from 
  first 
  to 
  last. 
  The 
  anal 
  fin 
  is 
  the 
  exact 
  counterpart 
  of 
  the 
  

   dorsal 
  fin. 
  In 
  Mr. 
  Clarke's 
  photograph 
  these 
  fins 
  do 
  not 
  occupy 
  half 
  

   that 
  space, 
  but 
  commence 
  much 
  nearer 
  to 
  the 
  tail, 
  and 
  decrease 
  very 
  

   rapidly 
  in 
  the 
  length 
  of 
  the 
  rays. 
  In 
  Platysomus 
  the 
  dorsal 
  fin 
  

   contains 
  from 
  80 
  to 
  100 
  fin-rays, 
  whereas 
  in 
  the 
  Australian 
  Fish 
  

   it 
  has 
  only 
  30. 
  The 
  caudal 
  fin 
  also 
  shows 
  very 
  different 
  characters 
  

   in 
  the 
  two 
  genera. 
  Platysomus 
  has 
  a 
  very 
  well 
  marked 
  heterocercal 
  

   tail, 
  whereas, 
  as 
  far 
  as 
  can 
  be 
  perceived 
  in 
  the 
  very 
  faint 
  photo- 
  

   graphic 
  record 
  of 
  this 
  organ 
  in 
  the 
  Australian 
  specimen, 
  no 
  trace 
  of 
  

   such 
  structure 
  can 
  be 
  detected. 
  The 
  cranial 
  bones 
  and 
  the 
  scales 
  are 
  

   neatly 
  ornamented 
  with 
  fine 
  granulations. 
  The 
  strength 
  of 
  the 
  

   articulating 
  rib 
  of 
  the 
  scales 
  has 
  been 
  already 
  alluded 
  to 
  ; 
  so 
  firm 
  is 
  

   the 
  union 
  of 
  the 
  scales 
  by 
  the 
  splices 
  effected 
  by 
  this 
  structure, 
  so 
  

   peculiar 
  to 
  the 
  Pycnodont 
  family, 
  that 
  not 
  a 
  single 
  dislocation 
  is 
  to 
  

   be 
  seen 
  in 
  the 
  specimen. 
  In 
  allusion 
  to 
  this 
  mechanism, 
  I 
  propose 
  to 
  

   name 
  this 
  genus 
  Cleiihrolepis 
  (xXeWpov, 
  a 
  lock 
  ; 
  Xcttis, 
  a 
  scale), 
  and 
  

   the 
  species 
  C. 
  granulatus. 
  

  

  There 
  remains 
  one 
  photograph 
  to 
  be 
  considered, 
  representing 
  a 
  Fish 
  

   found 
  at 
  Parsonage 
  Hill, 
  Paramatta. 
  After 
  the 
  closest 
  scrutiny, 
  I 
  

   have 
  been 
  unable 
  to 
  detect 
  any 
  difference 
  between 
  this 
  Fish 
  and 
  the 
  

   genus 
  Palceoniscus, 
  save 
  only 
  in 
  the 
  position 
  of 
  the 
  dorsal 
  fin, 
  which 
  

  

  b2 
  

  

  