﻿ETTGNATH1D.E. 
  285 
  

  

  Family 
  EUGNATHID^. 
  

  

  Trunk 
  fusiform 
  or 
  elongate, 
  not 
  much 
  laterally 
  compressed. 
  

   Cranial 
  and 
  facial 
  bones 
  moderately 
  robust, 
  externally 
  enamelled, 
  

   and 
  opercular 
  apparatus 
  complete 
  ; 
  mandibular 
  suspensorium 
  nearly 
  

   vertical 
  or 
  inclined 
  backwards, 
  and 
  gape 
  of 
  mouth 
  wide 
  ; 
  snout 
  not 
  

   produced 
  ; 
  premaxillae 
  in 
  contact 
  mesially 
  and 
  usually 
  separate 
  ; 
  

   marginal 
  teeth 
  conical, 
  and 
  larger 
  than 
  the 
  inner 
  teeth. 
  Notochord 
  

   usually 
  persistent, 
  the 
  vertebrae 
  very 
  rarely 
  more 
  than 
  incomplete 
  

   rings. 
  Pin-rays 
  robust, 
  articulated 
  and 
  divided 
  distally 
  ; 
  fulcra 
  

   conspicuous. 
  Dorsal 
  fin 
  short 
  and 
  acuminate. 
  Scales 
  rhombic, 
  

   sometimes 
  with 
  rounded 
  postero-inferior 
  angle. 
  

  

  Synopsis 
  of 
  Genera. 
  

  

  I. 
  Vertebral 
  ossifications 
  wanting 
  or 
  in 
  form 
  

   of 
  separate 
  pleurocentra 
  and 
  hypocentra, 
  

   sometimes 
  fused 
  into 
  rings. 
  

  

  (a) 
  Scales 
  thick. 
  

  

  Trunk 
  more 
  or 
  less 
  elongated 
  ; 
  marginal 
  

   teeth 
  large, 
  inner 
  teeth 
  minute 
  and 
  

   clustered 
  ; 
  dorsal 
  fin 
  in 
  advance 
  of 
  

   anal 
  : 
  caudal 
  fin 
  forked 
  ; 
  scales 
  pec- 
  

   tinated, 
  not 
  deepened 
  on 
  flank, 
  

   narrow 
  ventrally 
  JEugnathus 
  (p. 
  286). 
  

  

  Ditto, 
  but 
  trunk 
  deeper, 
  vertebral 
  ele- 
  

   ments 
  usually 
  more 
  robust, 
  and 
  teeth 
  

   smaller 
  Heterolepidotus 
  (p. 
  304). 
  

  

  Trunk 
  robust; 
  dorsal 
  fin 
  in" 
  advance 
  of 
  

   anal 
  ; 
  caudal 
  fin 
  forked 
  ; 
  flank-scales 
  

   not 
  much 
  deepened, 
  ventral 
  scales 
  

   nearly 
  or 
  quite 
  as 
  deep 
  as 
  broad 
  .... 
  Allolepidotus 
  (p. 
  315). 
  

  

  Trunk 
  elegantly 
  fusiform 
  ; 
  external 
  bones 
  

   highly 
  ornamented 
  with 
  ridges 
  ; 
  mar- 
  

   ginal 
  teeth 
  very 
  small 
  and 
  regular 
  ; 
  

   dorsal 
  fin 
  in 
  advance 
  of 
  anal 
  ; 
  caudal 
  

   fin 
  forked 
  ; 
  scales 
  all 
  narrow 
  and 
  

   elongated, 
  marked 
  with 
  longitudinal 
  

   furrows 
  Ptycholepis 
  (p. 
  316). 
  

  

  (b) 
  Scales 
  thin. 
  

  

  Caudal 
  pleurocentra 
  and 
  hypocentra 
  

   never 
  annular 
  ; 
  marginal 
  teeth 
  large, 
  

   splenial 
  teeth 
  smaller, 
  but 
  long, 
  

   slender 
  and 
  clustered; 
  dorsal 
  fin 
  in 
  

   advance 
  of 
  anal 
  ; 
  caudal 
  fin 
  forked 
  ; 
  

   scales 
  tuberculated 
  and 
  most 
  with 
  

   peg-and-socket 
  articulation 
  Osteorachis 
  (p. 
  324). 
  

  

  