﻿BELONORHYNCHID^). 
  17 
  

  

  are 
  shown. 
  There 
  are 
  no 
  satisfactory 
  indications 
  either 
  

   of 
  ribs 
  or 
  fins 
  ; 
  and 
  only 
  fragments 
  of 
  the 
  dorsal 
  series 
  of 
  

   ridge-scutes 
  are 
  preserved. 
  Enniskillen 
  Coll. 
  

  

  P. 
  965 
  d. 
  Imperfect 
  mandible, 
  much 
  ornamented, 
  with 
  part 
  of 
  the 
  series 
  

   of 
  arches 
  of 
  the 
  axial 
  skeleton 
  of 
  the 
  trunk. 
  Egerton 
  ColL 
  

  

  Belonorhynchus 
  brevirostris, 
  sp. 
  nov. 
  

   [Plate 
  II. 
  fig. 
  2.] 
  

  

  1858. 
  Belonostomus 
  acutus, 
  F. 
  A. 
  Quenstedt 
  (errore), 
  Der 
  Jura, 
  p. 
  234, 
  

  

  pi. 
  xxix. 
  fig. 
  8. 
  

   1892. 
  Saurorhynchus 
  acutus, 
  0. 
  M. 
  Reis, 
  Geogn. 
  Jahresh. 
  1891, 
  p. 
  145 
  

  

  (in 
  part), 
  figs. 
  1-3. 
  

  

  Type. 
  Head 
  ; 
  British 
  Museum. 
  

  

  A 
  species 
  of 
  moderate 
  size, 
  the 
  head 
  attaining 
  a 
  length 
  of 
  about 
  

   0-11. 
  Head 
  from 
  three 
  and 
  a 
  half 
  to 
  four 
  times 
  as 
  long 
  as 
  its 
  maxi- 
  

   mum 
  depth 
  ; 
  distance 
  between 
  the 
  orbit 
  and 
  occiput 
  scarcely 
  if 
  at 
  all 
  

   exceeding 
  the 
  maximum 
  depth 
  of 
  the 
  mandible, 
  and 
  the 
  angular 
  

   bone 
  of 
  the 
  latter 
  with 
  long, 
  nearly 
  vertical 
  hinder 
  border, 
  sharply 
  

   rounded 
  off 
  inferiorly 
  ; 
  dentition 
  powerful, 
  the 
  posterior 
  laniaries 
  

   widely 
  spaced 
  and 
  especially 
  robust; 
  superficial 
  ornament 
  con- 
  

   sisting 
  of 
  short 
  rugae, 
  the 
  majority 
  directed 
  longitudinally, 
  [Trunk 
  

   unknown.] 
  

  

  Form. 
  Sf 
  Loc. 
  Lower 
  Lias 
  : 
  Dorsetshire. 
  Upper 
  Lias 
  :' 
  "Wurtem- 
  

   berg 
  and 
  Yorkshire. 
  

  

  (i.) 
  Lower 
  Lias, 
  Lyme 
  Regis. 
  

  

  40726. 
  Type 
  specimen, 
  being 
  a 
  cranium 
  and 
  mandible 
  wanting 
  the 
  

   extremity 
  of 
  the 
  snout 
  and 
  marked 
  by 
  an 
  oblique 
  line 
  of 
  

   fracture 
  across 
  the 
  hinder 
  portion. 
  The 
  fossil 
  is 
  shown 
  

   of 
  the 
  natural 
  size 
  in 
  PI. 
  II. 
  fig. 
  2, 
  and 
  exhibits 
  the 
  

   principal 
  characters 
  of 
  the 
  head 
  from 
  the 
  right 
  lateral 
  aspect. 
  

   Remains 
  of 
  the 
  posterior 
  extension 
  of 
  the 
  cranial 
  roof 
  (r.) 
  

   occur 
  above 
  the 
  operculum 
  (op.), 
  which 
  is 
  very 
  small 
  and 
  

   similar 
  in 
  shape 
  to 
  that 
  of 
  B. 
  acutus. 
  The 
  orbit 
  (o.), 
  

   narial 
  opening 
  (n), 
  and 
  dentition 
  are 
  also 
  indicated 
  ; 
  and 
  

   the 
  form 
  of 
  the 
  hinder 
  portion 
  of 
  the 
  mandible 
  is 
  especially 
  

   well 
  shown. 
  The 
  very 
  large 
  articulo-angular 
  bone 
  exhibits 
  

   the 
  form 
  of 
  the 
  posterior 
  and 
  postero-inferior 
  margin 
  so 
  

   characteristic 
  of 
  the 
  species 
  ; 
  and 
  there 
  are 
  abraded 
  

   remains 
  of 
  the 
  series 
  of 
  short 
  vertical 
  sensory 
  canals 
  

   which 
  mark 
  its 
  upper 
  border. 
  Purchased, 
  1867. 
  

  

  39866. 
  Small 
  head 
  0*055 
  in 
  length, 
  the 
  maximum 
  depth 
  contained 
  

   about 
  three 
  times 
  in 
  the 
  total 
  length, 
  and 
  the 
  mandible 
  

  

  PART 
  III. 
  c 
  

  

  