﻿EUGNATHID^. 
  339 
  

  

  dorsal 
  fin 
  being 
  relatively 
  large. 
  Scales 
  in 
  part 
  ornamented 
  with 
  

   radiating 
  series 
  of 
  very 
  fine 
  granulations. 
  

  

  Form, 
  fy 
  Loc. 
  Lower 
  Kimmeridgian 
  (Lithographic 
  Stone) 
  : 
  Ain, 
  

   France. 
  

  

  Not 
  represented 
  in 
  the 
  Collection. 
  

  

  Caturus 
  angustus, 
  Agassiz. 
  

  

  1844. 
  Caturus 
  angustus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  ii. 
  p. 
  118. 
  

   1893. 
  Caturus 
  angustus, 
  A. 
  S. 
  Woodward, 
  Ann. 
  Mag. 
  Nat. 
  Hist. 
  [6] 
  

   vol. 
  xii. 
  p. 
  398, 
  pi. 
  xviii. 
  fig. 
  1. 
  

  

  Type. 
  Fish, 
  wanting 
  head 
  ; 
  Worcester 
  Museum. 
  

  

  An 
  imperfectly 
  defined 
  species, 
  known 
  only 
  by 
  the 
  type 
  specimen, 
  

   which 
  measures 
  # 
  16 
  from 
  the 
  origin 
  of 
  the 
  dorsal 
  to 
  the 
  fork 
  of 
  the 
  

   caudal 
  fin. 
  Trunk 
  much 
  elongated, 
  the 
  width 
  of 
  the 
  caudal 
  pedicle 
  

   scarcely 
  equalling 
  half 
  the 
  depth 
  of 
  the 
  trunk 
  between 
  the 
  dorsal 
  

   and 
  pelvic 
  fins. 
  The 
  origins 
  of 
  these 
  two 
  fins 
  directly 
  opposed, 
  and 
  

   the 
  dorsal 
  with 
  about 
  20 
  rays 
  ; 
  anal 
  fin 
  about 
  as 
  large 
  as 
  the 
  pelvic 
  

   fins, 
  with 
  not 
  less 
  than 
  12 
  rays. 
  

  

  Form. 
  Sf 
  Loc. 
  Portlandian 
  : 
  Garsington, 
  Oxford. 
  

  

  Not 
  represented 
  in 
  the 
  Collection. 
  

  

  Caturus 
  heterurus 
  (Agassiz). 
  

  

  [Plate 
  IX.] 
  

  

  1839-44. 
  Pachycormus 
  (?) 
  heterurus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  ii. 
  

   p. 
  113, 
  pi. 
  lviii. 
  a. 
  figs. 
  4, 
  5. 
  

  

  Type. 
  Tail 
  ; 
  Oxford 
  Museum. 
  

  

  A 
  robust 
  species 
  of 
  medium 
  size, 
  attaining 
  a 
  length 
  of 
  about 
  

   0*45. 
  Length 
  of 
  head 
  with 
  opercular 
  apparatus 
  exceeding 
  the 
  

   maximum 
  depth 
  of 
  the 
  trunk 
  and 
  contained 
  about 
  four 
  times 
  in 
  

   the 
  total 
  length 
  of 
  the 
  fish 
  ; 
  depth 
  of 
  caudal 
  pedicle 
  equalling 
  about 
  

   half 
  the 
  maximum 
  depth 
  of 
  the 
  trunk. 
  External 
  head-bones, 
  

   supratemporals, 
  and 
  opercular 
  bones 
  ornamented 
  only 
  in 
  part 
  with 
  

   feeble 
  rugse 
  and 
  tuberculations 
  ; 
  maxillary 
  teeth 
  small, 
  slender, 
  and 
  

   in 
  close 
  series, 
  premaxillary 
  teeth 
  larger, 
  and 
  those 
  of 
  the 
  dentary 
  

   bone 
  largest 
  and 
  stoutest, 
  well-spaced; 
  operculum 
  about 
  three- 
  

   quarters 
  as 
  broad 
  as 
  deep. 
  Hypocentra 
  and 
  pleurocentra 
  large, 
  

   well-ossified. 
  Dorsal 
  fin 
  comprising 
  18 
  rays, 
  arising 
  in 
  advance 
  of 
  

   the 
  middle 
  of 
  the 
  back, 
  about 
  as 
  deep 
  as 
  long, 
  and 
  its 
  maximum 
  

   depth 
  not 
  much 
  exceeding 
  half 
  that 
  of 
  the 
  trunk 
  at 
  its 
  origin 
  ; 
  

   pectoral 
  fins 
  with 
  loose 
  fulcra 
  ; 
  pelvic 
  fins 
  arising 
  opposite 
  the 
  front 
  

   half 
  of 
  the 
  dorsal; 
  anal 
  fin 
  comprising 
  only 
  9 
  or 
  10 
  rays, 
  arising 
  

   immediately 
  behind 
  termination 
  of 
  dorsal. 
  Scales 
  relatively 
  large, 
  

   some 
  exhibiting 
  a 
  very 
  feeble 
  radiating 
  crimping. 
  

  

  