﻿114 
  PAL2E0NT0L0GY 
  OF 
  ILLINOIS. 
  

  

  punotatioD 
  also 
  agrees. 
  The 
  present 
  form 
  is 
  represented 
  by 
  hall 
  ;i 
  

  

  dozen 
  or 
  so 
  imperfect 
  specimens, 
  which, 
  while 
  they 
  are 
  readily 
  

  

  ignizable, 
  are 
  insufficient 
  for 
  comparative 
  measurements 
  showing 
  

  

  their 
  proportionate 
  dimensions, 
  — 
  a 
  mature 
  example 
  having 
  a 
  trans- 
  

   verse 
  diameter 
  across 
  the 
  inner 
  margin 
  of 
  12.6 
  mm. 
  

  

  Maxillary 
  posterior 
  teeth 
  corresponding 
  in 
  dimensions 
  with 
  the 
  

   posterior 
  form 
  of 
  the 
  mandible, 
  presenting 
  the 
  general 
  outline 
  

   ascrihahle 
  to 
  this 
  form, 
  moderately 
  arched 
  Longitudinally 
  and 
  strongly 
  

   inrolled 
  along 
  the 
  outer 
  margin. 
  Antero-lateral 
  border 
  slightly 
  

   ohlique 
  to 
  a 
  right 
  line 
  connecting 
  the 
  inner 
  angles, 
  presenting 
  a 
  

   channeled 
  basal 
  rim 
  denned 
  above 
  by 
  the 
  narrow 
  inbeveled 
  fold 
  of 
  

   coronal 
  enamel; 
  postero-lateral 
  herder 
  approaching 
  point 
  of 
  inroll- 
  

   ment 
  at 
  an 
  angle 
  of 
  GO* 
  1 
  , 
  and 
  less, 
  to 
  the 
  opposite 
  border; 
  inner 
  

   margin 
  hroadly 
  arched 
  round 
  the 
  hase 
  of 
  the 
  posterior 
  lobe, 
  in 
  

   front 
  of 
  which 
  it 
  is 
  sharply 
  contracted 
  and 
  thence 
  continued 
  in 
  a 
  

   slightly 
  concave 
  course 
  to 
  the 
  anterior 
  prominent 
  . 
  round 
  which 
  it 
  

   makes 
  a 
  hroad 
  curve 
  terminating 
  in 
  the 
  obtuse 
  anterior 
  angle. 
  The 
  

   definition 
  of 
  the 
  anterior 
  and 
  posterior 
  regions 
  of 
  the 
  crown 
  is 
  

   marked; 
  posterior 
  lohe 
  occupying 
  apparently 
  less 
  than 
  half 
  the 
  

   lateral 
  diameter 
  of 
  the 
  tooth, 
  hroad 
  posterior 
  slope 
  gently 
  and 
  

   regularly 
  arched 
  transversely, 
  in 
  front 
  steeply 
  doping 
  from 
  the 
  

   sharply 
  rounded 
  crest 
  to 
  the 
  angulation 
  forming 
  its 
  anterior 
  limit 
  ; 
  

   the 
  surface 
  of 
  the 
  relatively 
  wide 
  depressed 
  median 
  belt 
  gently 
  

   rises 
  into 
  the 
  summit 
  of 
  the 
  anterior 
  lohes, 
  which 
  latter 
  usually 
  

   presents 
  a 
  more 
  or 
  less 
  well-defined, 
  narrow, 
  rounded 
  ri 
  be- 
  

  

  times 
  two 
  or 
  more 
  obscure 
  ridges, 
  in 
  pari 
  occupying 
  the 
  moderately 
  

   abrupt 
  slope 
  along 
  the 
  antero-lateral 
  border; 
  in 
  Bome 
  examp 
  

   faint 
  revolving 
  ridges 
  extend 
  over 
  the 
  depressed 
  median 
  belt, 
  and 
  

  

  in 
  others 
  ohscure 
  impressed 
  lilies 
  may 
  he 
  traced 
  in 
  the 
  wide 
  all 
  

  

  of 
  the 
  posterior 
  lobe. 
  In 
  the 
  perfect 
  state 
  the 
  entire 
  coronal 
  but- 
  

   face 
  was 
  oeoupied 
  by 
  transverse 
  ruga 
  parallel 
  with 
  the 
  inner 
  

  

  margin 
  and 
  mor< 
  or 
  less 
  so 
  to 
  one 
  another, 
  though 
  in 
  the 
  la 
  - 
  

  

  respect 
  exhibiting 
  considerable 
  variation 
  in 
  the 
  broken 
  continuity. 
  

   bifurcation, 
  and 
  implantation 
  of 
  the 
  rage, 
  which 
  have 
  the 
  same 
  

   appearance 
  as 
  in 
  the 
  preceding 
  tonus 
  mentioned 
  above. 
  Toward 
  

   the 
  outer 
  margin 
  and 
  indeed 
  over 
  the 
  middle 
  portion 
  of 
  the 
  crown 
  

  

  Where 
  its 
  surface 
  was 
  suhjectod 
  t. 
  1 
  1 
  1 
  lit 
  ion 
  while 
  in 
  D 
  

  

  tlie 
  ruga 
  an 
  ohsolete 
  or 
  marly 
  bo, 
  though 
  m 
  sonic 
  instances 
  still 
  

   traceable 
  in 
  the 
  disposition 
  in 
  transverse 
  lines 
  of 
  th< 
  mon 
  or 
  

   elongated 
  or 
  confluent 
  punote, 
  which 
  are 
  conspicuously 
  displayed 
  

  

  ■ 
  ntire 
  Surface 
  Save 
  along 
  the 
  inner 
  margin 
  where 
  the 
  

  

  