﻿110 
  ACTINOPTEKYGII. 
  

  

  pterygoid 
  are 
  partly 
  exposed, 
  and 
  the 
  preoperculum 
  

   appears 
  to 
  owe 
  its 
  peculiar 
  form 
  to 
  crushing 
  and 
  fracture. 
  

   The 
  operculum 
  and 
  suboperculum 
  are 
  also 
  much 
  broken, 
  

   but 
  their 
  true 
  proportions 
  seem 
  to 
  be 
  as 
  described 
  by 
  

   Agassiz. 
  The 
  uppermost 
  postclavicular 
  scale 
  is 
  con- 
  

   spicuous, 
  and 
  there 
  are 
  traces 
  of 
  the 
  elongated 
  basal 
  bones, 
  

   besides 
  the 
  coracoid, 
  at 
  the 
  origin 
  of 
  the 
  pectoral 
  fin. 
  The 
  

   fulcra 
  on 
  the 
  latter 
  are 
  distinctly 
  biserial, 
  and 
  the 
  fin-rays 
  

   are 
  undivided 
  except 
  quite 
  at 
  the 
  extremity. 
  The 
  

   obliquely-ridged 
  structure 
  of 
  the 
  scales 
  can 
  be 
  faintly 
  

   seen 
  through 
  the 
  enamel, 
  which 
  is 
  well 
  preserved. 
  

  

  Mantell 
  Coll 
  

  

  P. 
  6337. 
  A 
  fine 
  specimen, 
  originally 
  about 
  0*9 
  in 
  length, 
  wanting 
  

   the 
  extremity 
  of 
  the 
  snout 
  and 
  the 
  pectoral 
  fins, 
  but 
  

   displaying 
  part 
  of 
  the 
  base 
  of 
  each 
  of 
  the 
  other 
  fins 
  ; 
  

   Hastings. 
  The 
  opercular 
  and 
  head-bones 
  are 
  coarsely 
  

   tuberculated 
  as 
  in 
  the 
  type 
  specimen, 
  and 
  the 
  operculum 
  

   is 
  nearly 
  similar 
  in 
  proportions 
  ; 
  but 
  the 
  preoperculum 
  is 
  

   shaped 
  as 
  in 
  the 
  so-called 
  L. 
  fittoni, 
  and 
  the 
  suboperculum 
  

   seems 
  to 
  have 
  been 
  nearly 
  half 
  as 
  deep 
  as 
  the 
  operculum. 
  

   The 
  pelvic 
  fins 
  arise 
  considerably 
  nearer 
  to 
  the 
  position 
  of 
  

   the 
  pectoral 
  arch 
  than 
  to 
  the 
  anal, 
  and 
  both 
  these 
  fins 
  

   display 
  large 
  fulcra 
  ; 
  of 
  the 
  dorsal 
  and 
  caudal 
  fins 
  only 
  

   insignificant 
  fragments 
  remain. 
  The 
  dorsal 
  part 
  of 
  the 
  

   abdominal 
  region 
  is 
  crushed 
  and 
  displaced, 
  but 
  the 
  greater 
  

   part 
  of 
  the 
  squamation 
  is 
  undisturbed, 
  and 
  the 
  principal 
  

   fiank-scales 
  exhibit 
  a 
  feeble 
  pectination. 
  BecMes 
  Coll. 
  

  

  P. 
  6336. 
  Another 
  fine 
  specimen, 
  equally 
  large, 
  wanting 
  the 
  paired 
  

   fins 
  but 
  displaying 
  the 
  greater 
  part 
  of 
  the 
  anal 
  and 
  caudal 
  : 
  

   Hastings. 
  The 
  operculum 
  is 
  as 
  described 
  in 
  L. 
  fittoni, 
  

   but 
  whether 
  or 
  not 
  its 
  comparative 
  smoothness 
  is 
  due 
  to 
  

   abrasion, 
  is 
  uncertain 
  ; 
  the 
  cranial 
  and 
  facial 
  bones 
  are 
  

   irregularly 
  rugose, 
  not 
  exhibiting 
  sharp 
  tuberculations. 
  

   The 
  dorsal 
  fin 
  is 
  shown 
  to 
  have 
  arisen 
  at 
  about 
  the 
  middle 
  

   point 
  of 
  the 
  back, 
  but 
  only 
  the 
  large 
  anterior 
  fulcra 
  and 
  

   two 
  fragments 
  of 
  rays 
  are 
  preserved 
  ; 
  the 
  anal 
  fin, 
  with 
  

   numerous 
  more 
  slender 
  fulcra, 
  seems 
  to 
  have 
  been 
  deeper 
  

   than 
  long 
  ; 
  and 
  the 
  robust 
  caudal 
  fin-rays 
  are 
  shown 
  to 
  

   have 
  been 
  very 
  closely 
  articulated 
  quite 
  to 
  their 
  base. 
  All 
  

   the 
  scales 
  are 
  smooth, 
  but 
  those 
  on 
  the 
  anterior 
  portion 
  of 
  

   the 
  flank 
  exhibit 
  serrations, 
  and 
  each 
  scale 
  of 
  the 
  lateral 
  

   line 
  is 
  conspicuously 
  notched. 
  The 
  perforations 
  of 
  the 
  

  

  