﻿356 
  ACTINOPTERYGII. 
  

  

  having 
  been 
  subsequently 
  met 
  with 
  in 
  the 
  Collection. 
  Of 
  

   the 
  cranium, 
  only 
  the 
  highly-ornamented 
  posterior 
  portion 
  

   of 
  the 
  roof 
  is 
  exposed 
  (fig. 
  4 
  a), 
  and 
  the 
  parietals 
  (pa.) 
  

   are 
  shown 
  to 
  be 
  very 
  small, 
  the 
  squamosals 
  (sq.) 
  extending 
  

   about 
  twice 
  as 
  far 
  forwards, 
  and 
  the 
  frontals 
  (fr.) 
  uniting 
  

   in 
  a 
  wavy 
  median 
  suture. 
  The 
  smooth 
  hinder 
  margin 
  of 
  

   the 
  cranial 
  roof 
  must 
  have 
  been 
  deeply 
  overlapped 
  by 
  the 
  

   large 
  supratemporal 
  plates, 
  of 
  which 
  the 
  outermost 
  is 
  

   preserved 
  on 
  the 
  left 
  side. 
  The 
  rostral 
  half 
  of 
  the 
  skull 
  

   is 
  shown 
  in 
  irregular 
  transverse 
  section, 
  and 
  the 
  pterygo- 
  

   palatine 
  arcade 
  exhibits 
  a 
  large 
  laminar 
  bone, 
  apparently 
  

   the 
  entopterygoid, 
  covered 
  with 
  closely-arranged 
  tubercular 
  

   teeth, 
  which 
  become 
  elongated 
  towards 
  the 
  inferior 
  margin 
  

   and 
  are 
  nearly 
  as 
  large 
  on 
  the 
  ectopterygoid 
  (? 
  or 
  palatine) 
  

   as 
  on 
  the 
  maxilla. 
  On 
  the 
  right 
  side 
  the 
  greater 
  part 
  of 
  the 
  

   maxilla 
  (mx.), 
  with 
  an 
  elongated 
  supramaxilla 
  (s.mx.) 
  on 
  

   its 
  hinder 
  half, 
  is 
  preserved, 
  showing 
  some 
  traces 
  of 
  

   ornament 
  and 
  the 
  nearly 
  straight 
  dentigerous 
  border 
  ; 
  

   the 
  mandible 
  is 
  also 
  preserved, 
  but 
  more 
  imperfectly, 
  and 
  

   tall 
  conical 
  teeth 
  seem 
  to 
  occur 
  on 
  the 
  splenial 
  as 
  viewed 
  

   in 
  transverse 
  section. 
  Beneath 
  the 
  mandible 
  is 
  part 
  of 
  a 
  

   large, 
  thin, 
  ornamented 
  plate, 
  evidently 
  the 
  gular. 
  One 
  

   large 
  cheek-plate 
  (s.o.), 
  with 
  sparse 
  radiating 
  ornament, 
  

   is 
  also 
  shown 
  on 
  the 
  right 
  side. 
  The 
  post-temporal 
  plates 
  

   are 
  long 
  and 
  narrow, 
  and 
  ornamented 
  in 
  their 
  exposed 
  

   portion. 
  Two 
  fragments 
  of 
  the 
  operculum 
  (op.) 
  on 
  the 
  

   left 
  side 
  are 
  ornamented, 
  and 
  the 
  suboperculum 
  (s.op.) 
  on 
  

   the 
  right 
  side 
  is 
  more 
  than 
  half 
  as 
  deep 
  as 
  the 
  operculum. 
  

   The 
  last-named 
  and 
  remaining 
  characters 
  are 
  indicated 
  in 
  

   the 
  published 
  figure 
  and 
  description. 
  Purchased, 
  1871. 
  

  

  Neorhomholepis 
  valdensis, 
  sp. 
  nov. 
  

   [Plate 
  VIII. 
  fig. 
  5.] 
  

  

  Type. 
  Imperfect 
  fish 
  ; 
  British 
  Museum. 
  

  

  A 
  species 
  about 
  as 
  large 
  as 
  the 
  type, 
  similarly 
  known 
  only 
  from 
  

   an 
  imperfect 
  specimen. 
  Principal 
  flank-scales 
  and 
  many 
  of 
  the 
  

   narrow 
  ventral 
  scales 
  extremely 
  finely 
  pectinated 
  on 
  their 
  hinder 
  

   margin 
  ; 
  vertebral 
  centra 
  in 
  the 
  posterior 
  abdominal 
  region 
  rela- 
  

   tively 
  longer 
  than 
  in 
  N. 
  excelsus. 
  Other 
  characters, 
  so 
  far 
  as 
  

   known, 
  as 
  in 
  the 
  latter 
  species. 
  

  

  Form. 
  4' 
  Lot: 
  Wealden 
  : 
  Sussex. 
  

  

  