﻿semioxotid^:. 
  157 
  

  

  P. 
  5455 
  a. 
  Imperfect 
  head 
  with 
  opercular 
  apparatus, 
  and 
  fragment 
  

   of 
  trunk 
  with 
  pectoral 
  fin, 
  described 
  and 
  figured 
  ibid. 
  

   p. 
  141, 
  pi. 
  vi. 
  fig. 
  7. 
  

  

  Presented 
  by 
  Hugh 
  Eocton, 
  Esq., 
  M.D., 
  1888. 
  

  

  The 
  imperfectly 
  known 
  genus 
  Dipteronotus 
  (Egerton, 
  Quart. 
  

   Journ. 
  Geol. 
  Soc. 
  vol. 
  x. 
  1854, 
  p. 
  369) 
  appears 
  to 
  be 
  closely 
  related 
  

   to 
  Cleitlirolepis, 
  but 
  is 
  distinguished 
  at 
  least 
  by 
  its 
  much-elongated 
  

   dorsal 
  fin, 
  which 
  is 
  broken 
  in 
  the 
  type 
  specimen, 
  and 
  was 
  originally 
  

   described 
  by 
  Egerton 
  as 
  double. 
  A 
  single 
  species, 
  D. 
  cyplius, 
  is 
  

   determined 
  by 
  Egerton 
  (Joe. 
  cit. 
  p. 
  369, 
  pi. 
  xi.) 
  from 
  the 
  Keuper 
  of 
  

   Bromsgrove, 
  Worcestershire, 
  the 
  type 
  and 
  only 
  known 
  specimen 
  

   being 
  now 
  preserved 
  in 
  the 
  Museum 
  of 
  Practical 
  Geology, 
  London. 
  

  

  Genus 
  AETHEOLEPIS, 
  A. 
  S. 
  Woodward. 
  

  

  [Described 
  in 
  forthcoming 
  Mem. 
  Geol. 
  Surv. 
  N.S. 
  Wales, 
  

   Palasont. 
  no. 
  9.] 
  

  

  Trunk 
  deep 
  and 
  laterally 
  compressed. 
  Head 
  small, 
  and 
  external 
  

   bones 
  more 
  or 
  less 
  tuberculated. 
  Notochord 
  persistent, 
  apparently 
  

   without 
  ossifications 
  in 
  the 
  sheath. 
  Ein-fulcra 
  well 
  developed. 
  

   Pectoral 
  fins 
  placed 
  laterally 
  ; 
  pelvic 
  fins 
  of 
  moderate 
  size 
  ; 
  dorsal 
  

   and 
  anal 
  fins 
  extended, 
  acuminate 
  in 
  front, 
  and 
  both 
  remotely 
  

   situated 
  ; 
  [? 
  caudal 
  fin 
  not 
  forked]. 
  Scales 
  of 
  abdominal 
  region 
  

   thick, 
  much 
  deeper 
  than 
  broad 
  on 
  the 
  flank, 
  quadrate 
  in 
  form, 
  

   deeply 
  overlapping, 
  with 
  large 
  peg-and-socket 
  articulation, 
  and 
  an 
  

   anterior 
  inner 
  longitudinal 
  keel 
  ; 
  the 
  scales 
  of 
  this 
  form 
  gradually 
  

   passing 
  into 
  those 
  of 
  the 
  caudal 
  region, 
  which 
  are 
  very 
  thin, 
  deeply 
  

   imbricating, 
  and 
  more 
  or 
  less 
  oval 
  in 
  shape. 
  Scale-ornament 
  con- 
  

   sisting 
  of 
  tubercles. 
  

  

  Aetheolepis 
  mirabilis, 
  A. 
  S. 
  Woodward. 
  

  

  1893. 
  Aetheolepis, 
  A. 
  S. 
  Woodward, 
  Natural 
  Science, 
  vol. 
  iii. 
  p. 
  449, 
  

   woodc. 
  [Described 
  hi 
  forthcoming* 
  Mem. 
  Geol. 
  Surv. 
  N.S. 
  Wales, 
  

   Paheont. 
  no. 
  9.] 
  

  

  Type. 
  Nearly 
  complete 
  fish 
  ; 
  Museum 
  of 
  Geol. 
  Surv. 
  N.S. 
  Wales, 
  

   Sydney. 
  

  

  The 
  type 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  0*17. 
  Length 
  of 
  

   trunk 
  from 
  the 
  pectoral 
  arch 
  to 
  the 
  base 
  of 
  the 
  caudal 
  fin 
  equalling 
  

   scarcely 
  more 
  than 
  three-quarters 
  of 
  the 
  maximum 
  depth 
  ; 
  the 
  

   dorsal 
  margin 
  gibbously 
  curved, 
  the 
  ventral 
  margin 
  more 
  regularly 
  

   arched. 
  Head 
  with 
  opercular 
  apparatus 
  occupying 
  slightly 
  more 
  

   than 
  one-quarter 
  of 
  the 
  total 
  length 
  of 
  the 
  fish 
  to 
  the 
  base 
  of 
  the 
  

  

  