﻿PLATE 
  VIII. 
  

  

  PAGE. 
  

  

  Xtstkodus 
  inconditus, 
  St. 
  J. 
  and 
  W 
  179 
  

  

  Pig. 
  1 
  a. 
  Maxillary 
  posterior 
  tooth, 
  left 
  ramus, 
  view 
  from 
  above, 
  outline 
  restored; 
  1 
  

   b, 
  do., 
  profile 
  from 
  antero-lateral 
  border; 
  1 
  c, 
  do., 
  transverse 
  section. 
  

   Keokuk 
  limestone; 
  Warsaw, 
  Illinois. 
  Professor 
  "Worthen. 
  

  

  Xtstkodus 
  imitatus, 
  St. 
  J. 
  and 
  W 
  180 
  

  

  Fig. 
  2 
  a. 
  Maxillary 
  posterior 
  tooth, 
  right 
  ramus, 
  from 
  above; 
  2 
  b, 
  do., 
  longitudinal 
  

   profile 
  from 
  antero-lateral 
  border; 
  2 
  o, 
  do., 
  transverse 
  section. 
  St. 
  Louis 
  

   formation; 
  Monroe 
  county, 
  Illinois. 
  Professor 
  Worthen. 
  

  

  Xtstkodus 
  bellulus, 
  St. 
  J. 
  and 
  W 
  ...183 
  

  

  Fig. 
  3 
  a. 
  Maxillary 
  posterior 
  tooth, 
  left 
  ramus, 
  from 
  above, 
  outline 
  restored; 
  3 
  &, 
  do., 
  

   longitudinal 
  profile 
  from 
  the 
  antero-lateral 
  border; 
  3 
  c. 
  do., 
  transverse 
  

   section. 
  Coal 
  No. 
  7, 
  111. 
  Gen'l. 
  Sec; 
  Danville, 
  Illinois. 
  Mr. 
  Wm. 
  Gurley. 
  

  

  Xtstkodus 
  simplex, 
  St. 
  J. 
  and 
  W 
  178 
  

  

  y\ 
  Fig. 
  4 
  a. 
  Mandibular 
  posterior 
  tooth, 
  left 
  ramus, 
  view 
  from 
  above; 
  4 
  b, 
  do., 
  antero- 
  

   lateral 
  border; 
  4 
  c, 
  do., 
  from 
  postero-lateral 
  border; 
  4 
  d, 
  do., 
  inner 
  mar- 
  

   gin; 
  4 
  e, 
  do., 
  outer 
  inrolled 
  margin. 
  Upper 
  Burlington 
  limestone 
  fish- 
  

   bed; 
  Monmouth, 
  Illinois. 
  Mr. 
  Springer. 
  

   /( 
  Fig. 
  5 
  a. 
  Maxillary 
  posterior 
  tooth, 
  right 
  ramus, 
  from 
  above, 
  outline 
  restored; 
  5 
  5, 
  

   do., 
  from 
  the 
  antero-lateral 
  border; 
  5 
  c, 
  do., 
  postero-lateral 
  border; 
  5 
  d, 
  

   do., 
  transverse 
  profile 
  from 
  inner 
  margin; 
  5 
  e, 
  do., 
  outer 
  inrolled 
  ex- 
  

   tremity. 
  Upper 
  Burlington 
  limestone, 
  fish-bed; 
  Louisa 
  county, 
  Iowa. 
  

   Mr. 
  Springer. 
  

  

  Xtstkodus 
  verus, 
  St. 
  J. 
  and 
  W 
  181 
  

  

  Fig. 
  6 
  a. 
  Mandibular 
  posterior 
  teeth, 
  left 
  ramus, 
  view 
  from 
  above; 
  6 
  b, 
  do., 
  antero- 
  

   lateral 
  border, 
  longitudinal 
  profile; 
  6 
  c, 
  do., 
  transverse 
  profile 
  from 
  

   innermargin; 
  Chester 
  limestone; 
  Chester, 
  Illinois. 
  Professor 
  Worthen. 
  

   Fig. 
  7 
  a. 
  Maxillary 
  posterior 
  tooth, 
  left 
  ramus, 
  from 
  above; 
  7 
  6, 
  do., 
  longitudinal 
  pro- 
  

   file 
  from 
  the 
  antero-lateral 
  border; 
  7 
  c, 
  do., 
  from 
  the 
  postero-lateral 
  

   border; 
  7 
  d, 
  do., 
  transverse 
  profile 
  from 
  the 
  inner 
  margin. 
  Same 
  forma- 
  

   tion, 
  locality 
  and 
  collection. 
  

  

  . 
  Pcecilodus 
  St. 
  Ludovici, 
  St. 
  J. 
  and 
  W 
  132 
  

  

  /3o*P 
  ' 
  Fig. 
  8 
  a. 
  Mandible, 
  with 
  the 
  pair 
  of 
  posterior 
  teeth 
  occupying 
  their 
  natural 
  position, 
  

   resting 
  upon 
  the 
  granular 
  osseus 
  support, 
  the 
  right 
  ramus 
  showing 
  the 
  

   articular 
  processes 
  at 
  the 
  extremity. 
  The 
  anterior 
  extremity 
  of 
  the 
  jaw 
  

   is 
  mutilated, 
  but 
  it 
  is 
  evident 
  whatever 
  teeth 
  it 
  bore 
  were 
  extremely 
  

   i 
  small; 
  St. 
  Louis 
  limestone; 
  Alton, 
  Illinois. 
  Mr. 
  W. 
  C. 
  Van 
  Home. 
  

  

  I 
  ^ 
  0*1 
  V 
  ^ 
  g 
  ' 
  9 
  a 
  ' 
  Mandibular 
  posterior 
  tooth, 
  right 
  ramus, 
  view 
  from 
  above. 
  Same 
  forma- 
  

   tion, 
  locality 
  and 
  collection. 
  

   y/ 
  Fig. 
  10 
  a. 
  The 
  same 
  form, 
  left 
  ramus, 
  view 
  from 
  above; 
  10 
  b, 
  do., 
  outer 
  inrolled 
  mar- 
  

   gin; 
  10 
  c, 
  do., 
  from 
  inner 
  margin. 
  Same 
  formation, 
  locality 
  and 
  col- 
  

   v 
  lection. 
  

  

  1 
  3°*) 
  Fig 
  ' 
  n 
  "" 
  Maxil 
  l 
  ar 
  y 
  posterior 
  tooth, 
  right 
  ramus, 
  from 
  above; 
  11 
  b, 
  do., 
  from 
  the 
  outer 
  

  

  margin. 
  St. 
  Louis 
  formation; 
  Pella, 
  Iowa. 
  Mr. 
  St. 
  John. 
  

   Fig. 
  12 
  a. 
  Same 
  form, 
  left 
  ramus, 
  from 
  above; 
  12 
  b, 
  do., 
  from 
  inner 
  margin; 
  12 
  c, 
  do., 
  

   from 
  antero-lateral 
  border, 
  foreshortened; 
  St. 
  Louis; 
  Alton, 
  Illinois. 
  

   Professor 
  Worthen. 
  

  

  