﻿360 
  ACTINOPTERYGII. 
  

  

  Lophiostomus 
  affinis, 
  A. 
  S. 
  Woodward. 
  

  

  1895. 
  Lophiostomus 
  affinis, 
  A. 
  S. 
  Woodward, 
  Geol. 
  Mag. 
  [4] 
  vol. 
  ii. 
  

   p. 
  210, 
  pi. 
  viii. 
  fig. 
  6. 
  

  

  Type. 
  Hinder 
  portion 
  of 
  cranial 
  roof; 
  British 
  Museum. 
  

  

  A 
  species 
  as 
  large 
  asX. 
  dixoni, 
  known 
  only 
  by 
  the 
  hinder 
  portion 
  

   of 
  the 
  skull, 
  which 
  is 
  somewhat 
  more 
  finely 
  ornamented 
  than 
  in 
  the 
  

   type 
  species. 
  Frontal 
  prominences 
  slight, 
  not 
  forming 
  a 
  slender 
  

   eminence. 
  

  

  Form. 
  Sf 
  Loc. 
  Cenomanian 
  (Cambridge 
  Greensand) 
  : 
  Cambridge. 
  

  

  P. 
  7233. 
  Type 
  specimen 
  described 
  and 
  figured 
  loc. 
  cit. 
  Jesson 
  Coll: 
  

  

  Family 
  AMIID^. 
  

  

  Trunk 
  elongate 
  or 
  elongate-fusiform, 
  more 
  or 
  less 
  laterally 
  

   compressed. 
  Cranial 
  and 
  facial 
  bones 
  moderately 
  robust, 
  externally 
  

   enamelled, 
  and 
  opercular 
  apparatus 
  complete 
  ; 
  mandibular 
  suspen- 
  

   sorium 
  nearly 
  vertical 
  or 
  inclined 
  backwards, 
  and 
  gape 
  of 
  mouth 
  

   wide 
  ; 
  snout 
  not 
  produced 
  ; 
  premaxillae 
  separate 
  and 
  in 
  contact 
  

   mesially 
  ; 
  marginal 
  teeth 
  mostly 
  stout 
  and 
  conical, 
  inner 
  teeth 
  com- 
  

   paratively 
  small 
  or 
  even 
  minute. 
  Notochord 
  persistent 
  or 
  more 
  or 
  

   less 
  replaced 
  by 
  vertebras, 
  which 
  remain 
  as 
  disconnected 
  pleuro- 
  

   central 
  and 
  hypocentral 
  discs 
  in 
  part 
  of 
  the 
  caudal 
  region. 
  Fin-rays 
  

   robust, 
  the 
  majority 
  well-spaced, 
  articulated 
  and 
  divided 
  distally 
  ; 
  

   fulcra 
  almost 
  or 
  completely 
  wanting 
  ; 
  dorsal 
  and 
  anal 
  fins 
  variable 
  

   in 
  length. 
  Scales 
  thin 
  and 
  deeply 
  imbricating, 
  more 
  or 
  less 
  rounded 
  

   in 
  their 
  exposed 
  portion. 
  

  

  The 
  characters 
  of 
  the 
  genus 
  Liodesmns, 
  mentioned 
  below, 
  render 
  it 
  

   difficult 
  to 
  compile 
  a 
  satisfactory 
  diagnosis 
  of 
  this 
  family, 
  which 
  

   must 
  be 
  regarded 
  as 
  a 
  specialised 
  branch 
  of 
  the 
  Eugnathidae. 
  

  

  The 
  principal 
  descriptions 
  of 
  the 
  osteology 
  of 
  the 
  type 
  genus, 
  the 
  

   existing 
  Araia 
  of 
  North 
  American 
  lakes 
  and 
  rivers, 
  are 
  the 
  

   following 
  : 
  — 
  

  

  H. 
  Franque, 
  " 
  Afferuntur 
  nonnulla 
  ad 
  Amiam 
  calvam 
  accuratius 
  

  

  cognoscendam 
  " 
  (Inaugural 
  Dissertation 
  : 
  Berlin, 
  1847). 
  

   T. 
  W. 
  Bridge, 
  " 
  The 
  Cranial 
  Osteology 
  of 
  Amia 
  calva 
  " 
  (Journ. 
  

  

  Anatomy 
  & 
  Physiol, 
  vol. 
  xi. 
  1877, 
  pp. 
  605-622, 
  pi. 
  xxiii.). 
  

   M. 
  Sagemehl, 
  "Das 
  Cranium 
  von 
  Amia 
  calva 
  " 
  (Morphol. 
  Jahrb. 
  

  

  vol. 
  ix. 
  1884, 
  pp. 
  177-228, 
  pi. 
  x.). 
  

   E. 
  W. 
  Shufeldt, 
  " 
  The 
  Osteology 
  of 
  Amia 
  calva" 
  (Ann. 
  Eep. 
  U.S. 
  

  

  Commiss. 
  Fisheries, 
  1883 
  [1885], 
  pp. 
  747-878, 
  pis. 
  i.-x.). 
  

  

  