﻿Classification 
  of 
  the 
  Order 
  Synentognathi. 
  333 
  

  

  Family 
  2. 
  Scombresocidae. 
  

  

  Post-temporal 
  simple, 
  a 
  broad 
  lamina 
  anteriorly 
  overlapping 
  

   the 
  nearly 
  vertical 
  epiotic 
  and 
  pterotic 
  lamina 
  ; 
  supra- 
  

   cleithrum 
  a 
  small 
  bone 
  adherent 
  to 
  the 
  inner 
  face 
  of 
  the 
  

   post-temporal 
  at 
  its 
  posterior 
  edge. 
  Vertebras 
  65-70 
  *, 
  

   parapophyses 
  mostly 
  very 
  short, 
  with 
  the 
  ribs 
  nearly 
  sessile. 
  

   Jaws 
  more 
  or 
  less 
  produced 
  and 
  attenuated 
  forwards 
  ; 
  teeth 
  

   very 
  small. 
  Posterior 
  rays 
  of 
  dorsal 
  and 
  anal 
  detached 
  

   Unlets. 
  

  

  Two 
  genera, 
  Scombresox, 
  Lacep., 
  and 
  Cololabis, 
  Gill. 
  In 
  

   both 
  the 
  pharyngeal 
  bones 
  and 
  teeth 
  are 
  much 
  as 
  in 
  Belone 
  ; 
  

   the 
  third 
  upper 
  pharyngeals 
  are 
  moderately 
  large, 
  separate, 
  

   and 
  are 
  followed 
  by 
  the 
  very 
  small 
  fourth 
  pair, 
  which 
  bear 
  

   a 
  few 
  teeth 
  ; 
  the 
  lower 
  pharyngeals 
  form 
  a 
  moderately 
  broad 
  

   triangular 
  plate. 
  In 
  Scombresox 
  the 
  structure 
  of 
  the 
  jaws 
  is 
  

   exactly 
  as 
  in 
  the 
  Belonidse, 
  even 
  to 
  the 
  presence 
  of 
  the 
  inter- 
  

   locking 
  processes 
  which 
  unite 
  the 
  produced 
  portions 
  of 
  the 
  

   rami 
  of 
  the 
  lower 
  jaw; 
  the 
  absence 
  of 
  these 
  anterior 
  exten- 
  

   sions 
  in 
  Cololabis 
  may 
  be 
  regarded 
  as 
  probably 
  secondary. 
  

  

  Suborder 
  2. 
  Exocostoidea. 
  

  

  Synentognaths 
  with 
  rather 
  large 
  scales 
  and 
  small 
  mouth. 
  

   Second 
  and 
  third 
  upper 
  pharyngeals 
  dentigerous, 
  the 
  third 
  

   pair 
  strongly 
  enlarged, 
  together 
  forming 
  a 
  somewhat 
  convex 
  

   ovoid 
  plate 
  ; 
  fourth 
  upper 
  pharyngeals 
  absent 
  ; 
  lower 
  

   pharyngeal 
  broad, 
  triangular, 
  with 
  concave 
  upper 
  surface 
  ; 
  

   teeth 
  on 
  principal 
  pharyngeal 
  plates 
  anteriorly 
  villiform, 
  

   posteriorly 
  incisors 
  with 
  transversely 
  expanded 
  horizontal 
  

   edge, 
  the 
  two 
  types 
  connected 
  by 
  teeth 
  of 
  intermediate 
  

   form, 
  many 
  of 
  which 
  are 
  tricuspid. 
  Parasphenoid 
  with 
  an 
  

   inferior 
  apophysis 
  in 
  front 
  of 
  the 
  upper 
  pharyngeals 
  ; 
  myo- 
  

   dome 
  short, 
  a 
  deep 
  depression 
  between 
  its 
  outer 
  wall 
  and 
  the 
  

   prominent 
  compressed 
  auditory 
  bulla. 
  Post-temporal 
  and 
  

   supra-cleithrum 
  simple, 
  slender, 
  curved, 
  the 
  former 
  attached 
  

   along 
  the 
  posterior 
  edge 
  of 
  the 
  pterotic 
  lamina 
  ; 
  supra- 
  

   cleithrum 
  suspended 
  from 
  the 
  posterior 
  end 
  of 
  the 
  post- 
  

   temporal; 
  cleithrum 
  curved 
  inwards 
  above, 
  articulating 
  

   directly 
  with 
  basioccipital. 
  Each 
  pelvic 
  bone 
  of 
  an 
  anterior 
  

   subtriangular 
  lamina 
  and 
  an 
  erect 
  slender 
  process. 
  

  

  * 
  65 
  in 
  Scombresox 
  saurus 
  ; 
  70 
  in 
  the 
  Miocene 
  Scombresox 
  acutirostris 
  

   (Sauvage, 
  Ann. 
  Sci. 
  Ge"ol. 
  iv. 
  1873, 
  no. 
  1, 
  fig. 
  68, 
  and 
  xi. 
  1880, 
  no. 
  3, 
  

   p. 
  48). 
  

  

  