﻿276 
  ACTINOPXERYGII. 
  

  

  divided 
  distally. 
  Pelvic 
  fins 
  present 
  ; 
  dorsal 
  and 
  anal 
  fins 
  low 
  and 
  

   fringe-like, 
  the 
  former 
  occupying 
  the 
  greater 
  part 
  of 
  the 
  back 
  and 
  

   the 
  latter 
  much, 
  shorter, 
  arising 
  more 
  posteriorly 
  ; 
  caudal 
  fin 
  with 
  

   slightly 
  excavated 
  hinder 
  border. 
  Scales 
  covering 
  the 
  anterior 
  part 
  

   of 
  the 
  body 
  in 
  advance 
  of 
  the 
  median 
  fins. 
  

  

  Pycnodus 
  platessus 
  (Blainville). 
  

  

  1796. 
  Coryphcena 
  apoda, 
  G. 
  S. 
  Volta, 
  Ittiolit. 
  Veronese, 
  p. 
  cxlvii, 
  

  

  pi. 
  xxxv. 
  fig. 
  1. 
  

   1818. 
  Zeus 
  platessus, 
  H. 
  D. 
  de 
  Blainville, 
  Nouv. 
  Diet. 
  d'Hist. 
  Nat. 
  

  

  vol. 
  xxvii. 
  p. 
  356. 
  

   1833-44. 
  Pycnodus 
  platessus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  i. 
  

  

  p. 
  17, 
  pt. 
  ii. 
  p. 
  185, 
  pi. 
  lxxii. 
  figs. 
  1, 
  2 
  (non 
  figs. 
  3, 
  4). 
  

   1856. 
  Pycnodus 
  platessus, 
  J. 
  J. 
  Heckel, 
  Denkschr. 
  k. 
  Akad. 
  Wiss., 
  

  

  math.-naturw. 
  CI. 
  vol. 
  xi. 
  pp. 
  204, 
  226, 
  pi. 
  viii. 
  figs. 
  5, 
  7. 
  

  

  Type. 
  Nearly 
  complete 
  fish 
  ; 
  Paris 
  Museum 
  of 
  Natural 
  History. 
  

  

  The 
  type 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  0*3. 
  Maximum 
  

   depth 
  of 
  trunk 
  equalling 
  half 
  the 
  length 
  of 
  the 
  fish 
  exclusive 
  of 
  

   the 
  caudal 
  fin 
  ; 
  head 
  with 
  opercular 
  apparatus 
  occupying 
  about 
  

   one-quarter 
  of 
  the 
  total 
  length. 
  Teeth 
  of 
  the 
  splenial 
  bone 
  smooth, 
  

   the 
  outermost 
  indented 
  ; 
  the 
  inner 
  or 
  principal 
  series 
  equalling 
  in 
  

   breadth 
  the 
  two 
  flanking 
  series, 
  of 
  which 
  the 
  inner 
  comprises 
  teeth 
  

   broader 
  than 
  long, 
  the 
  outer 
  nearly 
  round 
  teeth. 
  Dorsal 
  fin 
  

   occupying 
  somewhat 
  less 
  than 
  three-quarters 
  of 
  the 
  total 
  length 
  of 
  

   the 
  back, 
  arising 
  almost 
  at 
  the 
  highest 
  point. 
  

  

  Form. 
  Sf 
  Log. 
  Upper 
  Eocene 
  : 
  N. 
  Italy. 
  

  

  38000. 
  Plaster 
  cast 
  of 
  type 
  specimen 
  ; 
  Monte 
  Bolca, 
  near 
  Verona. 
  

  

  Purchased, 
  1864. 
  

  

  41083. 
  Imperfect 
  specimen, 
  wanting 
  extremity 
  of 
  caudal 
  region, 
  

   displaying 
  the 
  right 
  splenial 
  dentition 
  ; 
  Monte 
  Bolca. 
  

  

  Purchased, 
  1868. 
  

  

  Pycnodus 
  gibbus, 
  Agassiz. 
  

  

  1796. 
  Coryphcena 
  apoda, 
  var., 
  G. 
  S. 
  Volta, 
  Ittiolit. 
  Veronese, 
  p. 
  cxlvii, 
  

   pi. 
  xxxv. 
  fig. 
  2. 
  

  

  1796. 
  Diodon 
  reticulatus, 
  G. 
  S. 
  Volta, 
  ibid. 
  p. 
  xciv, 
  pi. 
  xx. 
  fig. 
  3. 
  

  

  1844. 
  Pycnodus 
  gibbus 
  = 
  Pycnodus 
  platessus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  

   vol. 
  ii. 
  pt. 
  ii. 
  p. 
  185, 
  pi. 
  lxxii. 
  figs. 
  3, 
  4. 
  

  

  1856. 
  Pycnodus 
  gibbus. 
  J. 
  J. 
  Heckel, 
  Denkschr. 
  k. 
  Akad. 
  Wiss., 
  math.- 
  

   naturw. 
  CI. 
  vol. 
  xi. 
  p. 
  226, 
  pi. 
  viii. 
  figs. 
  3, 
  4, 
  6. 
  

  

  Type. 
  Nearly 
  complete 
  fish. 
  

  

  A 
  small 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  0'15. 
  Maximum 
  

   depth 
  of 
  trunk 
  slightly 
  exceeding 
  half 
  the 
  total 
  length 
  of 
  the 
  fish 
  

  

  