﻿DENTITION 
  OF 
  LEPIDOTUS 
  MAXIMUS. 
  357 
  

  

  PurbeCk 
  Beds 
  : 
  Mesodon, 
  Heck. 
  ; 
  Pycnodus, 
  Ag. 
  ; 
  Coelodas, 
  Heck. 
  ; 
  Microdon, 
  

   Ag. 
  ; 
  Lepidotics, 
  Ag. 
  ; 
  Pholidophorus, 
  Ag. 
  ; 
  Plearopholis, 
  

   Egert. 
  ; 
  Histionotus, 
  Egert. 
  ; 
  Ophiopsis, 
  Ag. 
  

  

  Wealden 
  : 
  Coelodus, 
  Heck. 
  ; 
  Lepidotics, 
  Ag. 
  

  

  Neocomian 
  : 
  Gyrodus, 
  Ag. 
  ; 
  Periodus, 
  Ag. 
  ; 
  Coelodas, 
  Heck. 
  

  

  Gault 
  : 
  Pycnodus, 
  Ag. 
  

  

  IT. 
  Greensand: 
  Coelodas, 
  Heck. 
  

  

  Chalk: 
  Gyrodus, 
  Ag.; 
  Acrotemnus, 
  Ag. 
  ; 
  Placodas, 
  Dixon 
  ; 
  Lepidotics, 
  Ag. 
  

  

  London 
  Clay 
  : 
  Pycnodus, 
  Ag. 
  ; 
  Gyrodus, 
  Ag. 
  

  

  Many 
  species 
  of 
  Lepidotus 
  attain 
  a 
  large 
  size. 
  Lepidotus 
  maximus, 
  

   "VVagn. 
  (=Sph(£rodus 
  gigas, 
  Ag.), 
  from 
  the 
  Lithographic 
  Stone 
  of 
  

   Solenhofen 
  in 
  Bavaria, 
  measures 
  over 
  5 
  feet 
  in 
  length 
  and 
  2 
  feet 
  in 
  

   depth 
  of 
  hody 
  ; 
  while 
  L. 
  Mantelli, 
  Ag., 
  from 
  the 
  Wealden 
  Series 
  

   (Hastings 
  Sand) 
  is 
  nearly, 
  if 
  not 
  quite, 
  of 
  equal 
  dimensions. 
  

  

  The 
  similarity 
  of 
  the 
  teeth 
  in 
  Sphcerodus 
  and 
  in 
  the 
  larger 
  species 
  

   of 
  Lepidotus 
  (such 
  as 
  L. 
  maximus) 
  induced 
  Agassiz 
  to 
  abolish 
  the 
  

   the 
  latter 
  genus 
  (but 
  with 
  hesitation) 
  in 
  1869. 
  Prof. 
  Owen, 
  how- 
  

   ever, 
  from 
  the 
  microscopic 
  structure 
  of 
  the 
  teeth, 
  regarded 
  the 
  two 
  

   genera 
  as 
  distinct. 
  On 
  the 
  other 
  hand, 
  many 
  continental 
  palseon- 
  

   tologists 
  have 
  rejected 
  the 
  genus 
  Splicerodus 
  as 
  being 
  founded 
  in 
  

   error. 
  

  

  Lepidotus 
  maximus, 
  Wagn. 
  ( 
  = 
  Sphcerodus 
  gigas, 
  Ag.), 
  has 
  been 
  

   found 
  in 
  the 
  Exogyra-virgula 
  stage 
  of 
  the 
  Kimeridge 
  Clay 
  at 
  both 
  

   Shotover 
  and 
  Kimeridge, 
  but 
  hitherto 
  only 
  separate 
  teeth 
  have 
  been 
  

   recorded. 
  Palatal 
  and 
  dentary 
  teeth, 
  equalling 
  in 
  perfection 
  those 
  

   described 
  and 
  figured 
  by 
  Pictet 
  and 
  Jaccard, 
  and 
  Sauvage, 
  and 
  illus- 
  

   trating 
  so 
  much 
  of 
  the 
  dentition, 
  have 
  never 
  previously 
  been 
  obtained 
  

   in 
  England. 
  

  

  The 
  "White 
  Jura 
  of 
  Schnaitheim 
  is 
  remarkable 
  for 
  the 
  identity 
  of 
  

   its 
  fish-fauna 
  with 
  that 
  of 
  the 
  Virgulian 
  beds 
  of 
  the 
  Neuchatel 
  

   Jura, 
  and 
  in 
  both 
  L. 
  maximus 
  occurs. 
  Prof. 
  John 
  Phillips 
  noticed 
  

   Splicerodus 
  gigas 
  ( 
  = 
  L. 
  maximus) 
  as 
  associated 
  with 
  Exogyra 
  vir- 
  

   gula 
  and 
  Ostrea 
  deltoidea 
  in 
  the 
  Kimeridge 
  Clay 
  of 
  Shotover, 
  in 
  

   both 
  the 
  upper 
  and 
  lower 
  zones 
  of 
  which 
  the 
  species 
  has 
  now 
  been 
  

   found. 
  

  

  Of 
  the 
  four 
  specimens 
  referred 
  to 
  in 
  the 
  present 
  paper 
  No. 
  I. 
  (in 
  

   two 
  pieces) 
  comprises 
  the 
  upper 
  dentition, 
  which 
  may 
  belong 
  to 
  the 
  

   same 
  individual 
  as 
  No. 
  IV. 
  Under 
  any 
  circumstances 
  the 
  specimens 
  

   belong 
  to 
  the 
  same 
  species. 
  18 
  teeth 
  occur 
  in 
  the 
  two 
  fragments 
  

   of 
  No. 
  I., 
  the 
  larger 
  posterior 
  portion 
  containing 
  five, 
  and 
  the 
  

   smaller 
  anterior 
  one 
  seven 
  teeth, 
  while 
  the 
  underside 
  of 
  the 
  latter 
  

   shows 
  six 
  teeth. 
  

  

  No. 
  II. 
  contains 
  two 
  teeth, 
  an 
  upper 
  and 
  a 
  lower, 
  belonging 
  to 
  

   the 
  same 
  species 
  as 
  No. 
  IY. 
  

  

  No. 
  III., 
  probably 
  the 
  right 
  dentary 
  bone, 
  appears 
  to 
  belong 
  to 
  

   a 
  distinct 
  species. 
  It 
  is 
  remarkably 
  perfect, 
  and 
  exhibits 
  sixteen 
  

   teeth, 
  of 
  which 
  the 
  successors 
  of 
  no 
  fewer 
  than 
  six 
  are 
  exposed 
  

   on 
  the 
  underside. 
  The 
  marginal 
  series 
  comprises 
  the 
  seven 
  smallest 
  

   teeth, 
  those 
  placed 
  most 
  inwardly 
  being 
  the 
  largest. 
  Compared 
  with 
  

   the 
  dentary 
  bone 
  of 
  those 
  species 
  of 
  which 
  that 
  element 
  is 
  already 
  

   known, 
  the 
  fossil 
  approaches 
  most 
  closely 
  to 
  Lepidotus 
  maximus, 
  

  

  