﻿402 
  ACTIlSrOPTERrGII. 
  

  

  laterally 
  compressed 
  by 
  accidental 
  crushing. 
  A 
  sclerotic 
  

   ring, 
  showing 
  some 
  traces 
  of 
  rugosity, 
  lies 
  in 
  the 
  matrix 
  

   beneath 
  the 
  fossil. 
  The 
  mandible 
  wants 
  its 
  hinder 
  

   extremity, 
  and 
  only 
  the 
  bases 
  of 
  the 
  larger 
  teeth 
  remain. 
  

   The 
  outer 
  face 
  of 
  the 
  anterior 
  end 
  of 
  the 
  dentary 
  is 
  very 
  

   coarsely 
  rugose, 
  and 
  the 
  symphysis 
  is 
  somewhat 
  expanded 
  

   for 
  the 
  sockets 
  of 
  the 
  three 
  anteriorly-directed 
  large 
  teeth. 
  

   Of 
  the 
  latter 
  on 
  the 
  left 
  side 
  the 
  uppermost 
  socket 
  appears 
  

   to 
  be 
  almost 
  obliterated. 
  There 
  is 
  no 
  suture 
  between 
  the 
  

   symphysial 
  end 
  and 
  the 
  remainder 
  of 
  the 
  dentary 
  bone, 
  

   but 
  it 
  exhibits 
  its 
  usual 
  slight 
  constriction 
  where 
  flanking 
  

   the 
  splenia], 
  and 
  the 
  oral 
  border 
  is 
  toothless 
  until- 
  a 
  point 
  

   considerably 
  behind 
  the 
  dentigerous 
  portion 
  of 
  the 
  inner 
  

   element. 
  The 
  teeth 
  of 
  its 
  single, 
  moderately 
  spaced 
  series 
  

   are 
  small 
  and 
  nearly 
  equal 
  in 
  size, 
  a 
  diminution 
  being 
  

   shown 
  only 
  in 
  the 
  foremost 
  five 
  or 
  six 
  ; 
  the 
  hindermost 
  

   teeth, 
  however, 
  are 
  not 
  preserved. 
  The 
  middle 
  portion 
  of 
  

   the 
  dentary 
  is 
  about 
  one- 
  third 
  deeper 
  than 
  its 
  symphysial 
  

   end, 
  much 
  thinner, 
  and 
  with 
  the 
  inferior 
  margin 
  slightly 
  

   turning 
  inwards. 
  The 
  splenials 
  evidently 
  enter 
  the 
  sym- 
  

   physis, 
  but 
  pyrites 
  obscures 
  their 
  anterior 
  end. 
  Viewed 
  

   from 
  above 
  each 
  is 
  lenticular 
  in 
  form, 
  though 
  produced 
  in 
  

   a 
  very 
  long 
  and 
  slender 
  extension 
  posteriorly 
  ; 
  and 
  the 
  

   thickest 
  portion 
  on 
  the 
  left 
  side 
  exhibits 
  the 
  bases 
  of 
  two 
  

   large 
  teeth 
  besides 
  one 
  small 
  anterior 
  tooth, 
  while 
  the 
  

   corresponding 
  part 
  on 
  the 
  right 
  side 
  seems 
  to 
  indicate 
  a 
  

   diseased 
  state 
  of 
  the 
  bone. 
  Fragments 
  of 
  other 
  elements 
  

   are 
  displaced 
  between 
  the 
  mandibular 
  rami, 
  but 
  it 
  is 
  

   impossible 
  to 
  determine 
  them. 
  Ennishillen 
  Coll. 
  

  

  P. 
  5651. 
  Fragments 
  of 
  skull 
  in 
  a 
  block 
  of 
  chalk 
  ; 
  Cuxton, 
  Kent. 
  

   A 
  portion 
  of 
  the 
  flattened 
  cranial 
  roof 
  is 
  rugose 
  on 
  the 
  

   external 
  surface, 
  but 
  affords 
  no 
  clue 
  to 
  the 
  arrangement 
  

   and 
  limits 
  of 
  the 
  elements. 
  The 
  imperfect 
  parasphenoid 
  

   is 
  exposed 
  from 
  the 
  inner 
  aspect, 
  showing 
  the 
  very 
  robust 
  

   though 
  narrow 
  bar 
  beneath 
  the 
  orbit, 
  and 
  the 
  much- 
  

   extended 
  laminar 
  basipterygoid 
  processes. 
  There 
  is 
  also 
  

   a 
  fragment 
  of 
  a 
  premaxilla 
  with 
  one 
  tooth. 
  

  

  Harford 
  Coll. 
  

  

  P. 
  5630. 
  Fine 
  rostrum, 
  much 
  fractured 
  but 
  displaying 
  the 
  super- 
  

   ficial 
  rugose 
  ornament 
  and 
  the 
  bases 
  of 
  the 
  vomerino 
  

   teeth, 
  and 
  apparently 
  not 
  distorted 
  by 
  crushing 
  ; 
  Kent. 
  

   A 
  side 
  view 
  of 
  this 
  fossil 
  is 
  given 
  in 
  outline, 
  of 
  one-half 
  

  

  