﻿EUGNATHlDiK. 
  3U5 
  

  

  1837-89. 
  Lepidotus 
  Jimbriatus, 
  L. 
  Agassiz, 
  ibid. 
  p. 
  247, 
  pi. 
  xxxiii.fi 
  

   (in 
  part). 
  [Scales; 
  Oxford 
  Museum.] 
  

  

  1837. 
  Semionotus 
  rhombifer, 
  L. 
  Agassiz, 
  ibid. 
  p. 
  228, 
  pi. 
  xxvi 
  a. 
  [Im- 
  

   perfect 
  fish 
  ; 
  British 
  Museum.] 
  

  

  1849. 
  Lepidotus 
  Jimbriatus, 
  W. 
  C. 
  Williamson, 
  Phil. 
  Trans, 
  p. 
  444. 
  

  

  1849. 
  Semionotus 
  rhombifer, 
  W. 
  C. 
  Williamson, 
  ibid. 
  p. 
  444, 
  pi. 
  xli. 
  fig. 
  9. 
  

  

  1868. 
  Eulepidotus 
  Jimbriatus, 
  Sir 
  P. 
  Egerton, 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  

   vol. 
  xxiv. 
  p. 
  505. 
  

  

  1872. 
  Heterolepidotus 
  latus, 
  Sir 
  P. 
  Egerton, 
  Figs. 
  & 
  Descript. 
  Brit. 
  

   Organic 
  Remains, 
  dec. 
  xiii. 
  (Mem. 
  Geol. 
  Surv.), 
  no. 
  2, 
  pi. 
  ii. 
  

  

  1887. 
  Heterolepidotus 
  Jimbriatus, 
  K. 
  A. 
  von 
  Zittel, 
  Handb. 
  Palaeont. 
  

   vol. 
  iii. 
  p. 
  204. 
  

  

  1890. 
  Eugnathus 
  latus, 
  Woodward 
  & 
  Sherborn, 
  Catal. 
  Brit. 
  Foss. 
  

   Vertebrata, 
  p. 
  78. 
  

  

  Type. 
  Nearly 
  complete 
  fish 
  ; 
  British 
  Museum. 
  

  

  A 
  large 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  0*7. 
  Length 
  of 
  head 
  

   with 
  opercular 
  apparatus 
  not 
  quite 
  equalling 
  the 
  maximum 
  depth 
  

   of 
  the 
  trunk 
  and 
  occupying 
  about 
  one-quarter 
  of 
  the 
  total 
  length 
  

   of 
  the 
  fish 
  ; 
  the 
  depth 
  of 
  the 
  caudal 
  pedicle 
  contained 
  two-and-a- 
  

   half 
  times 
  in 
  the 
  maximum 
  depth. 
  Cranium, 
  facial 
  bones, 
  opercular 
  

   bones, 
  and 
  the 
  well-developed 
  postclavicular 
  scales 
  ornamented 
  

   with 
  coarse 
  and 
  sparse 
  tuberculations 
  ; 
  operculum 
  about 
  two-thirds 
  

   as 
  broad 
  as 
  deep, 
  tapering 
  above, 
  and 
  its 
  maximum 
  breadth 
  

   equalling 
  nearly 
  one-third 
  the 
  length 
  of 
  the 
  cranium 
  ; 
  marginal 
  

   teeth 
  robust 
  and 
  acuminate, 
  and 
  the 
  teeth 
  on 
  the 
  splenial 
  bone 
  rela- 
  

   tively 
  large 
  anteriorly. 
  Dorsal 
  fin" 
  as 
  long 
  as 
  deep, 
  much 
  larger 
  

   than 
  the 
  anal 
  fin, 
  and 
  arising 
  opposite 
  the 
  origin 
  of 
  the 
  pelvic 
  pair. 
  

   Principal 
  scales 
  of 
  the 
  anterior 
  series 
  on 
  the 
  flank 
  slightly 
  deeper 
  

   than 
  broad, 
  and 
  marked 
  with 
  fine 
  ridges 
  terminating 
  in 
  the 
  serra- 
  

   tions 
  of 
  the 
  posterior 
  border 
  ; 
  most 
  of 
  the 
  flank 
  scales 
  and 
  ventral 
  

   scales 
  as 
  far 
  as 
  the 
  origin 
  of 
  the 
  dorsal 
  and 
  pelvic 
  fins 
  serrated, 
  the 
  

   others 
  smooth. 
  

  

  Though 
  not 
  clearly 
  indicated 
  by 
  Egerton, 
  this 
  may 
  be 
  regarded 
  

   as 
  the 
  type 
  species 
  of 
  the 
  genus 
  Heterolepidotus. 
  

  

  Form. 
  Sf 
  Loc. 
  Lower 
  Lias 
  : 
  Dorsetshire. 
  

  

  All 
  the 
  following 
  specimens 
  were 
  obtained 
  from 
  the 
  neighbour- 
  

   hood 
  of 
  Lyme 
  Eegis 
  : 
  — 
  

  

  38118. 
  The 
  type 
  specimen 
  figured 
  and 
  described 
  by 
  Egerton, 
  loc.cit. 
  

   1872. 
  "Purchased, 
  1864. 
  

  

  P. 
  2008. 
  Large 
  head 
  with 
  anterior 
  abdominal 
  squamation, 
  displaying 
  

   the- 
  opercular 
  apparatus 
  and 
  post-clavicular 
  plates, 
  noticed 
  

   by 
  Egerton. 
  ibid. 
  p. 
  3. 
  Egerton 
  Coll. 
  

  

  part 
  in. 
  x 
  

  

  