﻿EIIGNATHID^. 
  307 
  

  

  and 
  there 
  are 
  indications 
  of 
  a 
  similar 
  series 
  of 
  perforated 
  

   scales 
  on 
  the 
  dorsal 
  portion 
  of 
  the 
  flank, 
  extending 
  as 
  far 
  

   backwards 
  as 
  the 
  dorsal 
  fin. 
  One 
  of 
  the 
  pelvic 
  basal 
  bones 
  

   is 
  exposed. 
  Egerton 
  Coll. 
  

  

  P. 
  6423. 
  Distorted 
  and 
  partly 
  imperfect 
  specimen 
  about 
  0-5 
  in 
  

   length. 
  The 
  teeth 
  of 
  the 
  dentary 
  bone 
  are 
  very 
  closely 
  

   arranged. 
  Beckles 
  Coll. 
  

  

  P. 
  1538. 
  Imperfect 
  remains 
  of 
  head 
  and 
  greater 
  portion 
  of 
  trunk 
  of 
  

   a 
  similar 
  fish. 
  The 
  biserial 
  fulcra 
  are 
  well 
  shown 
  on 
  the 
  

   right 
  pelvic 
  fin. 
  Egerton 
  Coll. 
  

  

  P. 
  2011. 
  Trunk 
  with 
  median 
  fins. 
  Egerton 
  Coll. 
  

  

  P. 
  2010. 
  Small 
  specimen 
  about 
  0-36 
  in 
  length, 
  The 
  head 
  is 
  much 
  

   crushed, 
  and 
  parts 
  of 
  the 
  fins 
  are 
  wanting. 
  Egerton 
  Coll. 
  

  

  P. 
  1542. 
  Remains 
  of 
  small 
  specimen 
  originally 
  about 
  0*3 
  in 
  length. 
  

   The 
  head-bones 
  are 
  much 
  displaced, 
  so 
  that 
  several 
  internal 
  

   elements 
  are 
  shown. 
  The 
  paired 
  fins 
  are 
  preserved, 
  and 
  

   the 
  greater 
  part 
  of 
  the 
  rlank-squamation 
  is 
  exposed 
  from 
  

   within. 
  Egerton 
  Coll. 
  

  

  P. 
  3620. 
  The 
  type 
  specimen 
  of 
  the 
  so-called 
  Semionotus 
  rhombifer 
  

   described 
  by 
  Agassiz, 
  loc. 
  cit., 
  being 
  a 
  fish 
  somewhat 
  

   smaller 
  than 
  the 
  preceding 
  and 
  almost 
  certainly 
  the 
  young 
  

   of 
  Heterolepiclotus 
  latus. 
  The 
  comparative 
  smoothness 
  of 
  

   the 
  head-bones 
  and 
  post-clavicular 
  plates 
  is 
  apparently 
  

   due 
  to 
  imperfect 
  preservation. 
  Enniskillen 
  Coll. 
  

  

  P. 
  1538 
  b. 
  Middle 
  portion 
  of 
  trunk 
  of 
  a 
  similar 
  fish. 
  Egerton 
  Coll. 
  

  

  P. 
  1538 
  a. 
  Caudal 
  region 
  of 
  another 
  small 
  specimen. 
  Egerton 
  Coll. 
  

  

  Heterolepidotus 
  serrulatus 
  (Agassiz). 
  

  

  1843-44. 
  Lepidotus 
  serrulatus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  i. 
  

  

  p. 
  305, 
  pi. 
  xxxi. 
  

   1868. 
  Eulepidotus 
  sei-rulatus, 
  Sir 
  P. 
  Egerton, 
  Quart. 
  Journ. 
  Geol. 
  Soc 
  

  

  vol. 
  xxiv. 
  p. 
  505. 
  

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

  

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

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

  

  Vertebrata, 
  p. 
  79. 
  

  

  Type. 
  Fish 
  wanting 
  caudal 
  extremity 
  ; 
  British 
  Museum. 
  

   A 
  species 
  nearly 
  equalling 
  H. 
  latus 
  in 
  size, 
  but 
  differing 
  in 
  its 
  

   relatively 
  larger 
  and 
  smoother 
  scales, 
  and 
  in 
  the 
  robustness 
  of 
  the 
  

  

  x2 
  

  

  