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  ACTINOPTERYGII. 
  

  

  from 
  the 
  pectoral 
  arch 
  to 
  the 
  base 
  of 
  the 
  caudal 
  fin, 
  and 
  exceeding 
  

   twice 
  the 
  width 
  of 
  the 
  caudal 
  pedicle. 
  Suborbitals 
  subdivided 
  into 
  

   small 
  hexagonal 
  plates, 
  ornamented 
  with 
  granulations. 
  Dorsal 
  

   fin 
  comprising 
  more 
  than 
  45 
  rays, 
  its 
  anterior 
  portion 
  elevated 
  and 
  

   as 
  deep 
  as 
  the 
  trunk 
  at 
  its 
  point 
  of 
  origin. 
  Principal 
  flank-scales 
  

   deeper 
  than 
  broad, 
  smooth, 
  and 
  very 
  finely 
  denticulated 
  on 
  the 
  

   posterior 
  border. 
  (Pictet.) 
  

  

  Form. 
  &f 
  Loc. 
  Upper 
  Cretaceous 
  : 
  Mount 
  Lebanon, 
  Syria. 
  

  

  Not 
  represented 
  in 
  the 
  Collection. 
  

  

  Petalopteryx 
  dorsalis, 
  Davis. 
  

   1887. 
  Petalopteryx 
  dorsalis, 
  J. 
  W. 
  Davis, 
  Trans. 
  Roy. 
  Dublin 
  Soc. 
  [2] 
  

   vol. 
  iii. 
  p. 
  627, 
  pi. 
  xx. 
  fig. 
  4. 
  

  

  Type. 
  Fish 
  with 
  imperfect 
  fins 
  ; 
  British 
  Museum. 
  

  

  A 
  small 
  species, 
  attaining 
  a 
  length 
  of 
  0*075. 
  Length 
  of 
  head 
  

   with 
  opercular 
  apparatus 
  exceeding 
  the 
  maximum 
  depth 
  and 
  con- 
  

   tained 
  six 
  times 
  in 
  the 
  total 
  length 
  of 
  the 
  fish 
  to 
  the 
  base 
  of 
  the 
  

   caudal 
  fin 
  ; 
  maximum 
  depth 
  of 
  trunk 
  contained 
  nearly 
  six 
  times 
  in 
  

   its 
  length 
  from 
  the 
  pectoral 
  arch 
  to 
  the 
  base 
  of 
  the 
  caudal 
  fin, 
  and 
  

   twice 
  as 
  great 
  as 
  the 
  width 
  of 
  the 
  caudal 
  pedicle. 
  Tesserae 
  on 
  

   cheek 
  very 
  small, 
  elongated 
  antero-posteriorly, 
  and 
  smooth. 
  [Pins 
  

   imperfectly 
  known, 
  but] 
  pelvic 
  pair 
  comprised 
  within 
  the 
  first 
  third 
  

   of 
  the 
  trunk. 
  Scales 
  very 
  small 
  and 
  irregular, 
  all 
  apparently 
  at 
  

   least 
  as 
  broad 
  as 
  deep, 
  smooth, 
  and 
  not 
  serrated 
  on 
  the 
  posterior 
  

   margin. 
  

  

  Form. 
  Sf 
  Loc. 
  Upper 
  Cretaceous 
  : 
  Mount 
  Lebanon, 
  Syria. 
  

  

  P. 
  4755, 
  Type 
  specimen 
  described 
  and 
  figured 
  by 
  Davis, 
  loc. 
  cit. 
  : 
  

   Hakel. 
  The 
  lower 
  dentition 
  and 
  the 
  cheek-plates 
  are 
  

   especially 
  well 
  shown 
  in 
  the 
  head 
  ; 
  the 
  branchiostegal 
  

   rays 
  are 
  robust 
  though 
  filiform. 
  There 
  is 
  no 
  evidence 
  as 
  

   to 
  the 
  nature 
  of 
  the 
  vertebral 
  axis, 
  owing 
  to 
  the 
  thickness 
  

   of 
  the 
  squamation. 
  The 
  fins 
  are 
  too 
  imperfect 
  for 
  de- 
  

   scription, 
  and 
  it 
  is 
  impossible 
  to 
  determine 
  whether 
  or 
  

   not 
  the 
  anal 
  is 
  wanting 
  by 
  accident. 
  The 
  caudal 
  fin-rays 
  

   distinctly 
  bifurcate 
  once. 
  Except 
  in 
  the 
  posterior 
  half 
  of 
  

   the 
  caudal 
  region, 
  there 
  is 
  evidence 
  of 
  the 
  dichotomy 
  of 
  

   the 
  vertical 
  series 
  of 
  scales 
  both 
  dorsally 
  and 
  ventrally 
  ; 
  

   and, 
  as 
  noted 
  by 
  Davis, 
  some 
  of 
  the 
  small 
  scales 
  near 
  the 
  

   pectoral 
  fins 
  appear 
  to 
  be 
  rounded. 
  Lewis 
  Coll. 
  

  

  