﻿160 
  ACTINOPTEEYGII. 
  

  

  arches 
  were 
  much 
  expanded 
  or 
  that 
  small 
  ossifications 
  

   were 
  developed 
  in 
  the 
  notochordal 
  sheath. 
  

  

  Purchased, 
  1848, 
  

  

  19663-64. 
  A 
  large 
  distorted 
  fish 
  imperfect 
  dorsally, 
  in 
  counterpart 
  

   Boll. 
  Part 
  of 
  the 
  abdominal 
  squamation 
  is 
  displayed. 
  

  

  Purchased, 
  1845. 
  

  

  P. 
  1595, 
  P. 
  3625 
  a. 
  Imperfect 
  head 
  and 
  the 
  lower 
  portion 
  of 
  the 
  

   abdominal 
  region, 
  in 
  counterpart 
  ; 
  Boll. 
  

  

  Egerton 
  Sf 
  Ennishillen 
  Colls. 
  

  

  P. 
  3625 
  b, 
  C. 
  Two 
  typical 
  specimens 
  showing 
  the 
  feeble 
  character 
  

   of 
  the 
  squamation 
  in 
  the 
  caudal 
  region 
  ; 
  Boll. 
  The 
  first 
  

   specimen 
  displays 
  the 
  median 
  fins, 
  and 
  is 
  shown 
  of 
  the 
  

   natural 
  size 
  in 
  PI. 
  III. 
  fig. 
  1. 
  Ennishillen 
  Coll. 
  

  

  22531. 
  A 
  small 
  fish 
  0'065 
  in 
  length, 
  with 
  remains 
  of 
  all 
  the 
  fins 
  ; 
  

   Boll. 
  Like 
  No. 
  22524, 
  this 
  specimen 
  also 
  appears 
  to 
  

   exhibit 
  pleurocentra 
  and 
  hypocentra 
  in 
  the 
  caudal 
  region. 
  

  

  Purchased, 
  1848. 
  

  

  P. 
  1596. 
  Small 
  specimen 
  about 
  0*05 
  in 
  length, 
  labelled 
  T. 
  subser- 
  

   ratus 
  by 
  Egerton; 
  Banz, 
  Bavaria. 
  Egerton 
  Coll. 
  

  

  P. 
  1593, 
  P. 
  3626. 
  Two 
  very 
  imperfect 
  small 
  specimens, 
  the 
  second 
  

   wanting 
  the 
  caudal 
  region 
  and 
  the 
  first 
  wanting 
  also 
  the 
  

   head, 
  labelled 
  T. 
  cyclosoma 
  in 
  Egerton's 
  handwriting 
  and 
  

   evidently 
  to 
  be 
  regarded 
  as 
  the 
  types 
  of 
  that 
  species 
  ; 
  

   from 
  Banz 
  and 
  Ohmden 
  respectively. 
  

  

  Egerton 
  Sf 
  Enniskillen 
  Colls. 
  

  

  Tetragonolepis 
  discus, 
  Egerton. 
  

  

  1853. 
  Tetragonolepis 
  discus, 
  Sir 
  P. 
  Egerton, 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  

  

  vol. 
  ix. 
  p. 
  278, 
  pi. 
  xi. 
  fig. 
  5. 
  

   1860. 
  Pleurolepis 
  discus, 
  A. 
  Wagner, 
  Gelehrte 
  Anzeig. 
  k. 
  bay. 
  Akad. 
  

  

  Wiss. 
  p. 
  96. 
  

  

  Type. 
  Head 
  and 
  trunk 
  ; 
  collection 
  of 
  Rev. 
  P. 
  B. 
  Brodie. 
  

  

  A 
  smaller 
  species 
  than 
  the 
  type, 
  nearly 
  similar 
  in 
  proportions, 
  

   but 
  with 
  a 
  less 
  protuberant 
  abdominal 
  region 
  ; 
  the 
  greatest 
  depth 
  

   of 
  that 
  portion 
  of 
  the 
  trunk 
  below 
  the 
  vertebral 
  axis 
  less 
  than 
  three 
  

   times 
  as 
  great 
  as 
  that 
  of 
  the 
  portion 
  above 
  the 
  axis. 
  Scales 
  smooth, 
  

   or 
  with 
  slight 
  rugae 
  following 
  the 
  concentric 
  lines 
  of 
  growth, 
  the 
  

   hinder 
  border 
  not 
  serrated 
  ; 
  those 
  of 
  the 
  abdominal 
  flank 
  relatively 
  

   broad 
  ; 
  ventral 
  ridge-scales 
  very 
  finely 
  serrated. 
  

  

  Form. 
  Sf 
  Loc. 
  Upper 
  Lias 
  : 
  Gloucestershire. 
  

  

  