﻿Classification 
  of 
  some 
  Ttleostean 
  Fishes. 
  5 
  

  

  North 
  Atlantic 
  and 
  Japan, 
  has 
  the 
  dorsal, 
  with 
  IV 
  13-19 
  

   lays, 
  much 
  shorter 
  than 
  the 
  aval, 
  which 
  has 
  III-IV 
  26-30; 
  

   the 
  pelvics 
  have 
  I 
  10-13 
  lays. 
  The 
  latter 
  includes 
  three 
  

   recent 
  species 
  from 
  South 
  Australia 
  and 
  New 
  Zealand, 
  in 
  

   which 
  the 
  dorsal, 
  with 
  VT-VII 
  12-14 
  rays, 
  is 
  longer 
  than 
  

   the 
  anal, 
  which 
  has 
  IV 
  12-15, 
  whilst 
  the 
  pelvics 
  have 
  I 
  7 
  

   rays. 
  Moreover, 
  the 
  spines 
  are 
  stouter 
  than 
  in 
  Beryx, 
  and 
  

   the 
  scales 
  are 
  larger 
  and 
  structurally 
  different, 
  being 
  slightly 
  

   rugose 
  with 
  strongly 
  pectinated 
  edges, 
  instead 
  ot 
  covered 
  

   with 
  little 
  spines. 
  There 
  are 
  several 
  Cretaceous 
  species 
  of 
  

   Hophpteryx 
  ; 
  in 
  the 
  Australian 
  H. 
  affinis, 
  Giinth., 
  the 
  crests 
  

   and 
  ridges 
  on 
  the 
  head 
  are 
  arranged 
  exactly 
  as 
  in 
  the 
  

   Cretaceous 
  H. 
  lewisiensis 
  described 
  and 
  figured 
  by 
  Dr. 
  Smith 
  

   Woodward. 
  I 
  give 
  a 
  figure 
  of 
  H. 
  affinis, 
  for 
  comparison 
  with 
  

   the 
  extinct 
  forms 
  (PI. 
  I.). 
  

  

  Family 
  4. 
  Diretmidse. 
  

  

  The 
  type 
  of 
  Diretmus 
  aryenteus, 
  Johnson, 
  is 
  in 
  the 
  British 
  

   Museum 
  collection 
  ; 
  it 
  is 
  evidently 
  related 
  to 
  the 
  Berycidae. 
  

   The 
  dorsal 
  and 
  anal 
  fins 
  appear 
  to 
  be 
  formed 
  mainly 
  of 
  

   articulated 
  rays, 
  and 
  probably 
  not 
  more 
  than 
  3 
  or 
  4 
  are 
  

   spinous 
  ; 
  the 
  caudal 
  has 
  17 
  branched 
  rays 
  ; 
  each 
  pelvic 
  fin 
  

   is 
  composed 
  of 
  a 
  laminar, 
  oblong 
  ovate, 
  obliquely 
  striated 
  

   spine 
  and 
  5 
  branched 
  rays 
  ; 
  (the 
  pelvic 
  spine 
  of 
  Beryx 
  is 
  

   obliquely 
  striated). 
  The 
  scales 
  are 
  small, 
  adherent, 
  spinulose, 
  

   differing 
  from 
  those 
  of 
  Beryx 
  in 
  that 
  the 
  bases 
  of 
  the 
  spinules 
  

   are 
  expanded 
  into 
  parallel 
  vertical 
  ridges. 
  

  

  The 
  jaws 
  have 
  narrow 
  bands 
  of 
  villiform 
  teeth, 
  with 
  a 
  series 
  

   of 
  larger 
  pointed 
  teeth 
  in 
  the 
  lower; 
  the 
  palate 
  is 
  toothless. 
  

  

  The 
  single 
  large 
  supramaxillary 
  has 
  the 
  form 
  of 
  the 
  

   posterior 
  supramaxillary 
  of 
  the 
  Berycidse 
  ; 
  the 
  nasals 
  are 
  

   separated 
  by 
  the 
  prsemaxillary 
  processes; 
  the 
  subocular 
  shelf 
  

   and 
  the 
  alisphenoids 
  and 
  orbitosphenoids 
  are 
  as 
  in 
  the 
  

   Berycidas. 
  The 
  cranial 
  crests 
  and 
  ridges 
  are 
  as 
  in 
  the 
  Bery- 
  

   cidse, 
  except 
  that 
  the 
  paired 
  ridges 
  which 
  converge 
  forward 
  

   from 
  the 
  parietal 
  crests 
  in 
  the 
  latter 
  are 
  now 
  united 
  to 
  form 
  

   a 
  single 
  median 
  ridge, 
  owing 
  to 
  the 
  narrowness 
  of 
  the 
  inter- 
  

   orbital 
  region. 
  The 
  thin- 
  walled 
  auditory 
  bulla 
  containing 
  a 
  

   large 
  otolith 
  can 
  be 
  seen 
  above 
  the 
  gills. 
  The 
  pelvic 
  bones 
  

   are 
  embraced 
  by 
  the 
  enormously 
  expanded 
  hypocoracoids, 
  

   which 
  meet 
  in 
  a 
  long 
  symphysis 
  ; 
  this 
  is 
  an 
  exaggeration 
  of 
  

   the 
  Berycid 
  condition. 
  

  

  Family 
  5. 
  TrachichthyicUe. 
  

   Dorsal 
  and 
  anal 
  spines 
  few; 
  pelvic 
  fins 
  thoracic, 
  of 
  a 
  spine 
  

   and 
  6 
  soft 
  rays. 
  Jaws 
  and 
  dentition 
  as 
  in 
  the 
  Berycidas, 
  but 
  

  

  