﻿82 
  PALEONTOLOGY 
  OF 
  ILLINOIS. 
  

  

  Vatu'inodi 
  s 
  vbtustub, 
  Bt. 
  -J. 
  and 
  \Y. 
  

  

  PL 
  III. 
  PlK- 
  I. 
  

  

  The 
  unique 
  example 
  of 
  the 
  presenl 
  Bpeciea 
  represents 
  a 
  la 
  

   kerior 
  tooth 
  belonging 
  to 
  the 
  Left 
  ramus 
  of 
  the 
  upper 
  jaw. 
  It 
  

  

  elliptical 
  or 
  spatulate 
  in 
  general 
  outline, 
  moderately 
  arched 
  loi 
  | 
  

  

  tudinally, 
  and 
  apparently 
  strongly 
  inrolled 
  along 
  the 
  outer 
  margin, 
  

  

  terminating 
  posteriorly 
  in 
  a 
  sharply-rounded 
  angle 
  formed 
  by 
  41 
  

  

  posterior 
  hasal 
  spur, 
  which 
  extends 
  conspicuously 
  beyond 
  the 
  coronal 
  

  

  limits, 
  angle 
  of 
  obliquity 
  of 
  the 
  antero-lateral 
  border 
  not 
  shown, 
  but 
  

  

  evidently 
  forward 
  from 
  the 
  inner 
  angle. 
  The 
  tooth 
  is 
  considerably 
  

  

  thickened 
  in 
  the 
  region 
  of 
  the 
  posterior 
  border, 
  its 
  Bubstance 
  rapidly 
  

  

  diminishing 
  in 
  the 
  opposite 
  direction, 
  on 
  account 
  of 
  which 
  tic 
  

  

  rior 
  articular 
  border 
  is 
  liable 
  to 
  mutilation, 
  as 
  is 
  the 
  case 
  in 
  the 
  

  

  present 
  example. 
  The 
  basal 
  rim 
  along 
  the 
  posterolateral 
  border 
  

  

  forms 
  a 
  prominent 
  platform 
  projecting 
  beyond 
  the 
  coronal 
  border 
  for 
  

  

  half 
  the 
  distance 
  toward 
  the 
  point 
  of 
  inrollment, 
  the 
  coronal 
  enamel 
  

  

  forming 
  a 
  heavy 
  rounded 
  inbeveled 
  belt 
  distinctly 
  denned 
  from 
  I 
  

  

  basal 
  portion, 
  which 
  latter 
  also 
  forms 
  a 
  deep 
  border 
  along 
  tl 
  

  

  margin 
  of 
  the 
  tooth. 
  Inferior 
  surface 
  marked 
  by 
  interrupted 
  coarse 
  

  

  verrucose 
  stria?, 
  conforming 
  in 
  direction 
  to 
  that 
  of 
  the 
  inrollment 
  of 
  

  

  the 
  tooth. 
  The 
  crown 
  still 
  retains 
  along 
  the 
  inner 
  margin 
  tl 
  

  

  mal 
  coating 
  of 
  glossy 
  enamel, 
  the 
  summit 
  and 
  outer 
  region 
  exhil 
  

  

  ing 
  progress 
  rees 
  of 
  wear 
  from 
  use, 
  and 
  tine 
  punctate 
  structure, 
  

  

  inner 
  margin 
  distinctly 
  defined 
  from 
  the 
  base 
  by 
  the 
  limits 
  of 
  the 
  

  

  enamel 
  coating, 
  and 
  marked 
  by 
  parallel 
  lines 
  of 
  growth; 
  p 
  

  

  prominence 
  occupying 
  perhaps 
  one-third 
  the 
  lateral 
  diameter 
  of 
  ' 
  

  

  crown, 
  presenting 
  a 
  broad, 
  low 
  convexity 
  flattened 
  along 
  tfa 
  

  

  and 
  somewhat 
  depressed 
  from 
  within 
  outwards, 
  where 
  it 
  n 
  

  

  the 
  b//d.r 
  anterior 
  ana. 
  which 
  latl 
  miootb 
  and 
  without 
  longi- 
  rmm 
  

  

  tndinal 
  folds. 
  From 
  the 
  BUrfaOC 
  conformation, 
  and 
  direction 
  of 
  

  

  rollment, 
  it 
  La 
  Bafe 
  to 
  infer 
  the 
  BomewhaL 
  oblique 
  outward 
  and 
  I 
  

   ward 
  course 
  of 
  the 
  antero-lateral 
  bord 
  u11 
  

  

  probably 
  n. 
  :ir 
  18 
  OOntimetl 
  »t 
  "l' 
  ur 
  V 
  

  

  tm 
  breadth 
  near 
  middle 
  of 
  tooth 
  along 
  a 
  line 
  diagonal 
  

  

  to 
  the 
  Longitudinal 
  axis 
  r> 
  m 
  m. 
  

  

  The 
  mutilated 
  condition 
  of 
  tic 
  Uttple 
  Ti 
  

  

  ,..,t 
  allow 
  the 
  making 
  out 
  of 
  the 
  char* 
  

   Lateral 
  border; 
  otto 
  rv. 
  imen 
  permil 
  •»>• 
  

  

  i 
  with 
  allied 
  ooi 
  teeth. 
  Of 
  the 
  Latter 
  there 
  appeara 
  to 
  

  

  