﻿424 
  ACTINOPTEKYGII. 
  

  

  truncated 
  below, 
  strengthened 
  with 
  a 
  ridge 
  on 
  its 
  anterior 
  

   margin, 
  and 
  evidently 
  to 
  be 
  interpreted 
  as 
  the 
  left 
  post- 
  

   temporal 
  element. 
  The 
  presymphysial 
  bone 
  exhibits 
  its 
  

   characteristic 
  tapering 
  form, 
  with 
  the 
  large 
  unsymmetri- 
  

   cally-placed 
  tooth 
  at 
  its 
  base. 
  Most 
  of 
  the 
  scales 
  are 
  

   exposed 
  from 
  the 
  inner 
  aspect, 
  showing 
  the 
  large 
  peg-and- 
  

   socket 
  articulation 
  and 
  broad, 
  flattened, 
  inner 
  ridge 
  ; 
  but 
  

   the 
  external 
  face 
  is 
  evidently 
  rugose. 
  Purchased, 
  1867. 
  

  

  P. 
  7575. 
  Crushed 
  remains 
  of 
  small 
  head 
  and 
  abdominal 
  region. 
  

   The 
  large 
  teeth 
  on 
  the 
  presymphysial 
  bone 
  are 
  well 
  

   displayed. 
  History 
  unknown. 
  

  

  P. 
  967 
  a, 
  b. 
  Two 
  fragmentary 
  specimens 
  of 
  the 
  head 
  and 
  abdominal 
  

   region, 
  the 
  first 
  showing 
  the 
  base 
  of 
  the 
  pectoral 
  fin 
  and 
  

   the 
  rugose 
  ornament 
  of 
  the 
  scales, 
  besides 
  some 
  tuber- 
  

   culated 
  head-bones. 
  Egerton 
  Coll. 
  

  

  46345 
  — 
  a. 
  Small 
  head, 
  in 
  counterpart, 
  lateral 
  aspect, 
  showing 
  the 
  

   jaws 
  but 
  wanting 
  the 
  dentary 
  bone 
  ; 
  also 
  a 
  detached 
  

   rostrum. 
  Cunnington 
  Coll. 
  

  

  P. 
  5147, 
  P. 
  967 
  C 
  Imperfect 
  remains 
  of 
  a 
  small 
  head, 
  and 
  a 
  

   detached 
  rostrum. 
  Egerton 
  Coll. 
  

  

  P. 
  4281-2. 
  Portions 
  of 
  head 
  in 
  side 
  view, 
  showing 
  the 
  associated 
  

   rostrum, 
  presymphysial 
  bone, 
  operculum, 
  and 
  suboper- 
  

   culum, 
  and 
  detached 
  splenial 
  bones. 
  EnnisJcillen 
  Coll. 
  

  

  29042-44. 
  Pine 
  large 
  cranium 
  broken 
  across 
  the 
  middle, 
  the 
  cranial 
  

   roof 
  exposed 
  from 
  above 
  and 
  the 
  rostrum 
  from 
  below 
  

   (PL 
  XVII. 
  fig. 
  7) 
  ; 
  an 
  equally 
  large 
  cranium, 
  imperfect 
  

   behind, 
  displayed 
  from 
  the 
  infero-lateral 
  aspect 
  ; 
  and 
  a 
  

   detached 
  rostrum 
  with 
  premaxillary 
  dentition. 
  In 
  the 
  

   first 
  specimen, 
  as 
  shown 
  in 
  the 
  figure, 
  the 
  cranial 
  roof 
  is 
  

   ornamented 
  with 
  tubercles 
  and 
  longitudinal 
  rugse, 
  and 
  is 
  

   produced 
  backwards 
  at 
  its 
  postero-lateral 
  angles; 
  the 
  

   frontals 
  (fr.) 
  are 
  evidently 
  large 
  compared 
  with 
  the 
  

   parietals 
  (pa.), 
  though 
  the 
  intervening 
  suture 
  is 
  not 
  very 
  

   clear 
  ; 
  and 
  the 
  parasphenoid 
  (pas.) 
  is 
  crushed 
  outwards 
  

   on 
  the 
  right 
  side. 
  At 
  the 
  base 
  of 
  the 
  rostrum 
  a 
  V~ 
  sna 
  P 
  ec 
  ^ 
  

   eminence 
  (v.) 
  on 
  its 
  inferior 
  face 
  seems 
  to 
  represent 
  a 
  

   pair 
  of 
  toothless 
  vomers 
  united 
  in 
  front 
  ; 
  and 
  the 
  groove 
  

   between 
  the 
  long 
  dentigerous 
  premaxillae 
  (pmcu.) 
  is 
  con- 
  

   tinued 
  forwards 
  along 
  the 
  lower 
  face 
  of 
  the 
  rostral 
  prolon- 
  

   gation. 
  The 
  prefrontals 
  (pf.) 
  seem 
  to 
  have 
  been 
  well 
  

   ossified. 
  Purchased, 
  1854. 
  

  

  