﻿92 
  PALEONTOLOGY 
  OF 
  tLLINOl 
  

  

  Agass., 
  of 
  the 
  Mountain 
  limestone 
  of 
  Ireland 
  ; 
  and 
  almost 
  to 
  the 
  

   same 
  degree 
  the 
  maxillary 
  posterior 
  form 
  named 
  SUreblodm 
  

  

  is: 
  ( 
  .>, 
  from 
  the 
  same 
  deposits. 
  The 
  so-called 
  "termi- 
  

   nal" 
  tooth, 
  which 
  authors 
  ha 
  30Ciated 
  with 
  the 
  first 
  named 
  

   form, 
  is 
  strictly 
  more 
  intimately 
  related 
  to 
  PcecUodtts, 
  and 
  is 
  horn 
  

   with 
  the 
  mandibular 
  posterior 
  form, 
  as 
  shown 
  by 
  the 
  alate 
  postero- 
  

   lateral 
  border, 
  and 
  although 
  destitute 
  of 
  transverse 
  undula; 
  

   imbrications, 
  it 
  partakes 
  in 
  a 
  marked 
  degree 
  of 
  the 
  coronal 
  

   conformation 
  distinguishing 
  the 
  latter 
  genus. 
  Hence 
  we 
  are 
  stroi; 
  

   impressed 
  with 
  the 
  conviction 
  that 
  the 
  two 
  forms 
  h. 
  

   under 
  the 
  designation 
  1>. 
  aeutus 
  pertain 
  to 
  quite 
  distinct 
  gen< 
  

   categories, 
  and 
  that 
  there 
  exists 
  strong 
  probability 
  of 
  the 
  

   identity 
  with 
  the 
  present 
  forms 
  of 
  the 
  teeth 
  rehired 
  to 
  under 
  

   term 
  Streblodus 
  Coin, 
  and 
  their 
  possible 
  specific 
  identity 
  with 
  the 
  

   mandibular 
  posterior 
  (so-called 
  "anterior") 
  teeth 
  of 
  1>. 
  acutm. 
  The 
  

   typical 
  form 
  of 
  Streblodus 
  Colei, 
  however, 
  - 
  distinctions 
  which 
  

   might 
  readily 
  be 
  regarded 
  as 
  emphasized 
  specihe 
  variations, 
  

   compared 
  with 
  the 
  maxillary 
  posterior 
  form 
  of 
  Cochliodu 
  

   Agass., 
  (Streblodus 
  oblongus, 
  Agass.); 
  and 
  at 
  the 
  same 
  time 
  it 
  i 
  

   sents 
  an 
  extreme 
  departure 
  from 
  the 
  normal 
  chare 
  lishiug 
  

   the 
  same 
  form 
  which 
  is 
  here 
  ascribed 
  to 
  entative 
  American 
  

   species 
  of 
  Deltoptychius. 
  From 
  the 
  latter 
  the 
  Irish 
  form 
  is 
  distin- 
  

   guished 
  by 
  the 
  considerable 
  breadth 
  of 
  the 
  depressed 
  interval 
  

   separating 
  the 
  narrow 
  secondary 
  Lobe 
  from 
  the 
  posterior 
  coronal 
  

   prominence 
  and 
  the 
  consequent 
  relatively 
  narrower 
  

   which 
  latter 
  is 
  nearly 
  plain 
  and 
  terminated 
  | 
  

   scribed. 
  It 
  will, 
  tb 
  . 
  be 
  observed 
  on 
  close 
  inspection 
  of 
  the 
  

   Irish 
  and 
  American 
  forms 
  that, 
  while 
  they 
  differ 
  in 
  the 
  above 
  

  

  pect, 
  they 
  are 
  more 
  intimately 
  relate. 
  1 
  to 
  one 
  another 
  t 
  hair 
  ' 
  

   former 
  is 
  with 
  the 
  maxillary 
  posterior 
  tooth 
  of 
  C< 
  

   oblongus,) 
  and 
  it 
  is 
  on 
  these 
  grounds 
  we 
  have 
  been 
  led 
  

   its 
  gem 
  rie 
  identity 
  with 
  Deltoptychius, 
  -.. 
  ded. 
  The 
  

  

  b 
  form 
  referred 
  by 
  authors 
  to 
  the 
  "terminal" 
  tooth 
  of 
  D< 
  

  

  ehius, 
  is 
  not 
  met 
  with 
  in 
  this 
  country, 
  01 
  

  

  mentioned, 
  it 
  should 
  b 
  I 
  with 
  the 
  mandibul 
  

  

  form 
  of 
  Pcecilodus. 
  YYc 
  are, 
  however, 
  not 
  aware 
  that 
  the 
  Irish 
  local- 
  

  

  Horded 
  other 
  PaecUodus 
  forms 
  which 
  m 
  lly 
  

  

  identified 
  with 
  the 
  latter. 
  

  

  