﻿300 
  Mr. 
  A. 
  S. 
  Woodward's 
  Palaiichthyological 
  Notes. 
  

  

  Coal-measures 
  of 
  Lanarkshire 
  *. 
  This 
  form 
  of 
  tooth 
  is 
  dis- 
  

   tinguished 
  from 
  that 
  of 
  the 
  Keuper 
  by 
  the 
  less 
  elongation 
  of 
  

   the 
  horizontally 
  extended 
  root, 
  the 
  greater 
  development 
  of 
  the 
  

   median 
  denticle, 
  and 
  the 
  keeled 
  apices 
  of 
  the 
  coronal 
  cusps 
  ; 
  

   and 
  Mr. 
  Moore 
  himself 
  having 
  recognized 
  the 
  affinities 
  of 
  the 
  

   teeth 
  under 
  discussion, 
  they 
  may 
  most 
  appropriately 
  receive 
  

   the 
  name 
  of 
  Diplodus 
  Moorei. 
  

  

  The 
  term 
  Diplodus 
  is, 
  of 
  course, 
  only 
  one 
  of 
  provisional 
  

   value, 
  and 
  does 
  not 
  necessarily 
  imply 
  that 
  the 
  Keuper 
  teeth 
  

   pertain 
  to 
  the 
  same 
  genus 
  as 
  those 
  of 
  the 
  Carboniferous 
  and 
  

   Permian, 
  if, 
  indeed, 
  the 
  latter 
  belong 
  to 
  not 
  more 
  than 
  one 
  

   generic 
  type. 
  Some 
  " 
  species 
  " 
  certainly 
  form 
  the 
  dentition 
  

   of 
  Plew 
  ■acanthus, 
  and 
  all 
  probably 
  pertain 
  to 
  fishes 
  of 
  the 
  

   same 
  primitive 
  Elasmobranch 
  group 
  as 
  this 
  genus. 
  Although 
  

   no 
  Pleuracanth 
  spines 
  have 
  yet 
  been 
  found 
  in 
  the 
  Keuper, 
  

   Diplodus 
  Moorei 
  may 
  thus 
  imply 
  that 
  the 
  typical 
  members 
  of 
  

   Cope's 
  Ichthyotomi 
  had 
  nOt 
  become 
  extinct 
  in 
  late 
  Triassic 
  

   times 
  ; 
  but 
  the 
  discovery 
  of 
  skeletons 
  must 
  be 
  awaited 
  before 
  

   so 
  interesting 
  a 
  fact 
  can 
  be 
  reasonably 
  established. 
  

  

  3. 
  On 
  a 
  Symmetrical 
  Hybodont 
  Tooth 
  from 
  the 
  Oxford 
  Clay 
  

   of 
  Peterborough. 
  

  

  The 
  collection 
  of 
  Oxfordian 
  Vertebrates 
  made 
  by 
  Alfred 
  N. 
  

   Leeds, 
  Esq., 
  of 
  Eyebury, 
  Peterborough, 
  has 
  already 
  furnished 
  

   materials 
  for 
  the 
  definition 
  of 
  one 
  Mesozoic 
  Selachian 
  genus, 
  

   Asteracanthus 
  t 
  j 
  and 
  it 
  still 
  comprises 
  important 
  novelties, 
  

   elucidating 
  other 
  Selachian 
  and 
  Chimseroid 
  genera 
  of 
  the 
  same 
  

   age. 
  Among 
  these 
  fossils 
  is 
  a 
  symmetrical 
  Selachian 
  tooth, 
  

   shown 
  of 
  the 
  natural 
  size 
  from 
  the 
  outer, 
  inner, 
  lateral, 
  and 
  

   inferior 
  aspects 
  in 
  PI. 
  XIV. 
  fig. 
  6. 
  

  

  This 
  tooth 
  exhibits 
  a 
  large 
  median 
  coronal 
  cusp, 
  erect 
  and 
  

   obtusely 
  pointed, 
  flanked 
  in 
  a 
  symmetrical 
  manner 
  on 
  either 
  

   side 
  by 
  four 
  small 
  cusps, 
  diminishing 
  downwards 
  and 
  out- 
  

   wards. 
  The 
  entire 
  crown 
  is 
  much 
  inclined 
  inwards, 
  as 
  shown 
  

   in 
  side-view 
  ; 
  and 
  this 
  is 
  fixed 
  upon 
  the 
  anterior 
  margin 
  of 
  

   a 
  broad 
  depressed 
  base 
  or 
  root. 
  The 
  lower 
  front 
  edge 
  of 
  the 
  

   latter 
  is 
  coarsely 
  crimped, 
  and 
  its 
  lateral 
  margins 
  are 
  straight, 
  

   somewhat 
  converging 
  behind, 
  and 
  forming 
  well-marked 
  angles 
  

   with 
  the 
  hinder 
  margin. 
  

  

  The 
  specimen 
  is 
  probably 
  referable 
  to 
  the 
  symphysis 
  of 
  the 
  

   jaw 
  of 
  one 
  of 
  the 
  Hybodont 
  sharks 
  with 
  high-crowned 
  teeth, 
  

  

  * 
  Smith 
  Woodward, 
  Cat. 
  Foss. 
  Fishes 
  Brit. 
  Mus. 
  pt. 
  i. 
  (1889), 
  p. 
  11, 
  

   pi. 
  vi. 
  figs. 
  2-4. 
  

  

  f 
  Smith 
  Woodward, 
  Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  [6] 
  vol. 
  ii. 
  (1888), 
  

   pp. 
  330-342, 
  pi. 
  xii. 
  

  

  