﻿

  110 
  PALEONTOLOGY 
  OF 
  ILLINOIS. 
  

  

  enamel 
  fold 
  as 
  observed 
  in 
  the 
  opposite 
  border 
  ; 
  inner 
  margin 
  most 
  

   strongly 
  arched 
  backward 
  in 
  passing 
  the 
  base 
  of 
  the 
  prominent 
  

   median 
  lobe 
  of 
  the 
  crown, 
  with 
  deep, 
  broad 
  sinus 
  or 
  deflection 
  in 
  

   the 
  region 
  of 
  the 
  posterior 
  alation, 
  in 
  general 
  presenting 
  a 
  modci 
  

   aigmoidal 
  curvature, 
  inferior 
  edge 
  usually 
  inbeveled, 
  though 
  origin- 
  

   ally, 
  or 
  when 
  entire, 
  continued 
  downward 
  in 
  a 
  nearly 
  vertical 
  basal 
  

   wall; 
  outline 
  of 
  the 
  outer 
  inrolled 
  margin 
  tl. 
  se 
  of 
  that 
  last 
  

  

  d( 
  scribed. 
  Coronal 
  region 
  presenting 
  a 
  principal 
  or 
  median 
  ridge 
  

   culminating 
  near 
  the 
  middle 
  of 
  the 
  crown, 
  the 
  anterior 
  slope 
  mode- 
  

   rate 
  and 
  uniform 
  to 
  the 
  angulation 
  or 
  slight 
  depression 
  defining 
  the 
  

   very 
  narrow 
  belt 
  skirting 
  the 
  antero-lateral 
  border; 
  the 
  posterior 
  

   slope 
  more 
  abruptly 
  descends 
  into 
  the 
  broad 
  depression 
  in 
  that 
  

   flank, 
  whence 
  arises 
  the 
  prominent 
  posterior 
  alation. 
  Coronal 
  sur- 
  

   face 
  further 
  marked 
  by 
  subordinate 
  revolving 
  ridges 
  and 
  furrows 
  

   variable 
  in 
  disposition 
  and 
  distinctness 
  of 
  definition, 
  also 
  oniamei: 
  

   by 
  delicate 
  transverse 
  ruga' 
  or 
  reversed 
  imbrications 
  disposed 
  in 
  

   more 
  or 
  less 
  parallel 
  order 
  conforming 
  to 
  some 
  degree 
  with 
  the 
  

   t/aje*/-/ 
  direction 
  of 
  the 
  minw 
  margin, 
  though 
  subject 
  to 
  interruption 
  by 
  

   ' 
  implantation 
  and 
  bifurcation, 
  also 
  obsolete 
  or 
  variable 
  in 
  oooom 
  i 
  

   in 
  Bpeeies 
  and 
  individuals; 
  otherwise 
  the 
  surface 
  presents 
  the 
  punc- 
  

   tate 
  structure 
  common 
  to 
  allied 
  genera. 
  Inferior 
  surface, 
  enveloped 
  

   in 
  the 
  dense 
  homogeneous 
  layer, 
  smooth 
  or 
  faintly 
  striated 
  longi- 
  

   tudinally, 
  repeating 
  in 
  a 
  le6S 
  marked 
  degree 
  the 
  coronal 
  contour. 
  

  

  .Median 
  teeth 
  of 
  mandibles 
  relatively 
  narrow, 
  trapezoidal 
  in 
  out- 
  

   line, 
  arohed 
  and 
  ly 
  inrolled 
  longitudinally: 
  lateral 
  

   border 
  conforming 
  to 
  the 
  articular 
  border 
  of 
  the 
  posterior 
  form 
  and 
  

  

  constituting 
  the 
  longer 
  side 
  of 
  the 
  tooth, 
  antero-lab 
  ral 
  border 
  grad- 
  

   ually 
  oonveri 
  ing 
  toward 
  tin 
  out< 
  c 
  extremity, 
  both 
  borders 
  showing 
  the 
  

   channeled 
  basal 
  portion 
  bordered 
  above 
  by 
  the 
  narrow 
  inbevi 
  

   enamel 
  fold, 
  inner 
  margin 
  obliquely 
  rounded 
  from 
  the 
  posterior 
  to 
  

   the 
  anterior 
  obtuse 
  angle. 
  Corona] 
  Buriace 
  occupied 
  by 
  i 
  mon 
  

   less 
  prominent 
  ridge 
  situated 
  nearest 
  the 
  postero-lateral 
  border, 
  on 
  

   whiofa 
  side 
  the 
  declivity 
  is 
  abrupt, 
  and 
  defined 
  by 
  a 
  narrow 
  subor- 
  

   dinate 
  lobe 
  immediately 
  along 
  the 
  border, 
  op] 
  lidi 
  mon 
  

   aally 
  Bloping 
  toward- 
  the 
  antero-lateral 
  border, 
  winch 
  is 
  similarly 
  

   margined 
  by 
  a 
  narrow 
  ridge 
  with 
  int. 
  rv< 
  allow 
  furrow. 
  Sur- 
  

   face 
  ornamentation 
  tlie 
  same 
  a- 
  noted 
  in 
  connection 
  with 
  the 
  ] 
  

  

  1. 
  1 
  ior 
  terminal 
  form. 
  

   Maxillary 
  post* 
  th 
  subquadrilateral 
  in 
  general 
  outlii 
  

  

  ttely 
  arched 
  and 
  strongly 
  inrolled 
  along 
  the 
  outer 
  margin. 
  Ant. 
  

  

  lateral 
  border 
  alightlj 
  oblique 
  to 
  th< 
  

  

  