﻿PACHTCOKMIDJE. 
  

  

  383 
  

  

  while 
  the 
  form 
  and 
  proportions 
  of 
  the 
  head 
  and 
  operculum 
  are 
  

   regarded 
  as 
  the 
  most 
  important 
  specific 
  characters. 
  

  

  Pachycormus 
  macropterus 
  (Blainville). 
  

  

  1755. 
  Figure 
  by 
  A. 
  J. 
  Dezallier 
  dArgenville, 
  Oryctologie, 
  pi. 
  xviii. 
  

  

  fig. 
  1. 
  

   1805. 
  Figure 
  by 
  B. 
  Faujas 
  St. 
  Fond, 
  Essai 
  de 
  Geologie, 
  vol. 
  i. 
  p. 
  122, 
  

  

  pi. 
  viii. 
  

   1818. 
  Elops 
  macropterus, 
  H. 
  D. 
  de 
  Blainville, 
  Nouv. 
  Diet. 
  d'Hist. 
  Nat. 
  

  

  toI. 
  xxvii. 
  p. 
  324. 
  

   1833-44. 
  Pachycormus 
  macropterus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  

  

  pt. 
  i. 
  p. 
  12 
  ; 
  pt. 
  ii. 
  p. 
  Ill, 
  pi. 
  lix. 
  a. 
  

   1848. 
  Pachycormus 
  macropterus, 
  C. 
  G. 
  Giebel, 
  Fauna 
  d. 
  Vorw., 
  Fische, 
  

  

  p. 
  197. 
  

   1858. 
  Pachycormus 
  macropterus, 
  F. 
  A. 
  Quenstedt, 
  Der 
  Jura, 
  p. 
  236, 
  

  

  pi. 
  xxxii. 
  fig. 
  5. 
  

   1860. 
  Pachycormus 
  macroptenis, 
  A. 
  Wagner, 
  Gelehrte 
  Anzeig. 
  k. 
  bay. 
  

  

  Akad. 
  Wiss. 
  vol. 
  1. 
  p. 
  221 
  (in 
  part). 
  

   1883. 
  Pachycormus 
  macropterus, 
  H. 
  E. 
  Sauvage, 
  Bull. 
  Soc. 
  Linn. 
  

  

  Normandie, 
  [3] 
  vol. 
  vii. 
  p. 
  144, 
  pi. 
  iv. 
  

   (?) 
  1887. 
  Pachycormus 
  macropterus, 
  K. 
  A. 
  vonZittel, 
  Handb. 
  Palaeont. 
  

  

  vol. 
  iii. 
  p. 
  224, 
  fig. 
  237. 
  

  

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

  

  The 
  type 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  1*0. 
  Head 
  with 
  

   opercular 
  apparatus 
  occupying 
  somewhat 
  more 
  than 
  one-quarter 
  of 
  

   the 
  total 
  length 
  of 
  the 
  fish; 
  head 
  much 
  elongated 
  and 
  snout 
  obtuse, 
  

   the 
  ratio 
  between 
  the 
  length 
  of 
  the 
  head 
  from 
  the 
  median 
  elevation 
  

   to 
  the 
  end 
  of 
  the 
  snout 
  and 
  the 
  width 
  of 
  the 
  head 
  near 
  the 
  occiput 
  

   being 
  9:7; 
  operculum 
  triangular, 
  almost 
  or 
  quite 
  as 
  broad 
  as 
  deep, 
  

   and 
  branchiostegal 
  rays 
  about 
  50 
  in 
  number. 
  Dorsal 
  fin 
  with 
  about 
  

   30-35 
  rays, 
  arising 
  at 
  the 
  middle' 
  point 
  of 
  the 
  back 
  and 
  well 
  in 
  

   advance 
  of 
  the 
  anal 
  fin, 
  which 
  is 
  equally 
  extended. 
  Scales 
  of 
  mode- 
  

   rate 
  size, 
  mostly 
  smooth 
  but 
  in 
  part 
  faintly 
  rugose. 
  

  

  Form. 
  § 
  Log. 
  Upper 
  Lias 
  : 
  N. 
  and 
  E. 
  France 
  ; 
  Wiirtemberg 
  ; 
  

   Somersetshire 
  & 
  Yorkshire. 
  

  

  20657. 
  Specimen 
  0*96 
  in 
  length, 
  with 
  imperfect 
  head 
  ; 
  Boll, 
  Wiir- 
  

   temberg. 
  The 
  anal 
  fin 
  is 
  shown 
  well 
  behind 
  the 
  dorsal, 
  

   and 
  about 
  28 
  rays 
  can 
  be 
  counted 
  in 
  each. 
  

  

  Purchased, 
  1846. 
  

  

  P. 
  7569. 
  Imperfect 
  fish 
  about 
  0-7 
  in 
  length; 
  Ohmden, 
  Wiirtemberg. 
  

   Some 
  of 
  the 
  dorsal 
  scales 
  are 
  ornamented 
  with 
  a 
  faint 
  

   rugosity. 
  Purchased. 
  

  

  