﻿406 
  ACTINOPTEKYGII. 
  

  

  circular 
  in 
  transverse 
  section 
  in 
  its 
  distal 
  portion 
  ; 
  the 
  top 
  of 
  the 
  

   base 
  gradually 
  becoming 
  flattened 
  as 
  it 
  passes 
  into 
  the 
  cranial 
  roof. 
  

   External 
  ornament 
  as 
  in 
  P. 
  ferooc. 
  

   Form. 
  6f 
  Loc. 
  Senonian 
  : 
  Kent. 
  

  

  P. 
  5631. 
  The 
  type 
  specimen, 
  a 
  fractured 
  rostrum 
  showing 
  the 
  bases 
  

   of 
  the 
  pair 
  of 
  vomerine 
  teeth 
  ; 
  Chalk, 
  Kent. 
  A 
  diagram- 
  

   matic 
  outline 
  of 
  the 
  left 
  side-view 
  of 
  the 
  fossil 
  is 
  shown 
  

   of 
  half 
  the 
  natural 
  size 
  in 
  fig. 
  41, 
  no. 
  2 
  (p. 
  403), 
  and 
  trans- 
  

   verse 
  sections 
  are 
  given 
  ibid. 
  nos. 
  2 
  a-c. 
  Harford 
  Coll. 
  

  

  Protosphyrsena 
  minor 
  (Agassiz). 
  

  

  1837-44. 
  Tetrapterus 
  minor, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  v. 
  pt. 
  i. 
  pp. 
  7, 
  

  

  91, 
  pi. 
  lx. 
  a. 
  figs. 
  9, 
  10 
  (non 
  figs. 
  11-13). 
  

   1888. 
  Protosphyrcena 
  minor, 
  A. 
  S. 
  Woodward, 
  Proc. 
  Geol. 
  Assoc. 
  

  

  vol. 
  x. 
  p. 
  321. 
  

   1890. 
  Protosphyrcena 
  minor, 
  J. 
  Felix, 
  Zeitschr. 
  deutsch. 
  geol. 
  Ges. 
  

  

  vol. 
  xlii. 
  p. 
  299. 
  

  

  Type. 
  Fragment 
  of 
  rostrum 
  ; 
  British 
  Museum. 
  

  

  Nostrum 
  comparatively 
  delicate 
  and 
  much 
  elongated, 
  attaining 
  a 
  

   length 
  of 
  at 
  least 
  0*15 
  ; 
  the 
  transverse 
  section 
  a 
  depressed 
  oval 
  

   throughout 
  its 
  length, 
  and 
  the 
  internal 
  cavity 
  extending 
  a 
  con- 
  

   siderable 
  distance 
  towards 
  the 
  gradually 
  tapering 
  end 
  ; 
  the 
  external 
  

   surface 
  ornamented 
  with 
  coarse, 
  closely-arranged, 
  parallel 
  longitu- 
  

   dinal 
  ridges, 
  and 
  its 
  upper 
  aspect 
  marked 
  with 
  a 
  median 
  longitudinal 
  

   groove 
  which 
  does 
  not 
  obliterate 
  the 
  ornamentation. 
  

  

  No 
  portion 
  of 
  this 
  fish 
  except 
  the 
  rostrum 
  has 
  hitherto 
  been 
  

   identified. 
  

  

  Form. 
  Sf 
  Log. 
  Turonian 
  : 
  Kent 
  and 
  Sussex. 
  

  

  4078. 
  Fragment 
  of 
  rostrum 
  described 
  and 
  figured 
  by 
  Agassiz, 
  

   loc. 
  cit. 
  ; 
  Chalk, 
  Lewes. 
  The 
  extremity 
  of 
  the 
  fossil 
  was 
  

   missing 
  when 
  received 
  by 
  the 
  Museum. 
  Mantell 
  Coll. 
  

  

  49758. 
  Larger 
  portion 
  of 
  a 
  similar 
  rostrum, 
  much 
  fractured 
  ; 
  Grey 
  

   Chalk, 
  Lewes. 
  Capron 
  Coll. 
  

  

  49100. 
  Another 
  crushed 
  and 
  broken 
  specimen, 
  displaying 
  the 
  large 
  

   internal 
  cavity 
  and 
  the 
  superficial 
  ornamentation; 
  pro- 
  

   bably 
  from 
  the 
  Lower 
  Chalk 
  of 
  Burham, 
  Kent. 
  

  

  Mrs. 
  Smith's 
  Coll. 
  

  

  32337. 
  Distal 
  end 
  of 
  rostrum, 
  displaying 
  ornament 
  and 
  apparently 
  

   worn 
  towards 
  the 
  extremity; 
  Lower 
  Chalk, 
  Burham. 
  

   The 
  ridged 
  ornament 
  is 
  more 
  irregular 
  on 
  the 
  inferior 
  

   than 
  on 
  the 
  superior 
  aspect. 
  Purchased, 
  1857. 
  

  

  