﻿138 
  O. 
  C. 
  Marsh—The 
  Stylinodontia. 
  

  

  The 
  Skull 
  and 
  Teeth. 
  

  

  Figures 
  1 
  and 
  2, 
  below, 
  represent 
  respectively 
  a 
  portion 
  

   of 
  a 
  large 
  front 
  incisiform 
  tooth 
  of 
  the 
  lower 
  jaw 
  of 
  Stylino- 
  

   don, 
  and 
  several 
  of 
  the 
  adjacent 
  molar 
  series, 
  all 
  natural 
  size, 
  

   and 
  pertaining 
  to 
  the 
  original 
  type 
  specimen 
  of 
  Stylinodon 
  

   mirus. 
  The 
  peculiar 
  sculpture 
  of 
  the 
  enamel 
  of 
  the 
  anterior 
  

   tooth, 
  showing 
  both 
  the 
  longitudinal 
  grooves 
  and 
  the 
  trans- 
  

   verse 
  lines 
  of 
  growth, 
  is 
  a 
  characteristic 
  feature 
  of 
  these 
  teeth. 
  

   In 
  the 
  molars, 
  the 
  two 
  bands 
  of 
  enamel, 
  external 
  and 
  internal, 
  

   show 
  markings 
  similar, 
  but 
  less 
  distinct. 
  The 
  large 
  front 
  tooth 
  

   is 
  apparently 
  from 
  the 
  left 
  side, 
  the 
  enamel 
  shown 
  being 
  thus 
  

   on 
  the 
  outer 
  face. 
  The 
  other 
  specimen 
  containing 
  the 
  molar 
  

   teeth 
  is 
  part 
  of 
  the 
  right 
  lower 
  jaw, 
  with 
  the 
  inner 
  face 
  

   removed, 
  showing 
  the 
  base 
  of 
  the 
  teeth. 
  The 
  sockets 
  of 
  six 
  of 
  

   these 
  are 
  represented 
  in 
  figure 
  2, 
  and 
  behind 
  them 
  one 
  more 
  

   may 
  be 
  seen 
  in 
  the 
  inner 
  part 
  of 
  the 
  jaw, 
  making 
  together 
  

   seven 
  in 
  this 
  series, 
  all 
  of 
  similar 
  form 
  and 
  size. 
  The 
  lower 
  

   jaw 
  containing 
  these 
  eight 
  teeth 
  was 
  short, 
  deep, 
  and 
  massive, 
  

   with 
  a 
  strong 
  coronoid 
  process, 
  the 
  base 
  of 
  which 
  was 
  in 
  

   advance 
  of 
  the 
  posterior 
  teeth. 
  

  

  In 
  the 
  second 
  specimen 
  of 
  Stylinodon 
  already 
  mentioned, 
  

   the 
  lower 
  jaws 
  agree 
  in 
  all 
  respects 
  with 
  the 
  type. 
  The 
  seven 
  

   molar 
  teeth 
  have 
  the 
  same 
  position 
  and 
  proportions 
  as 
  in 
  that 
  

   specimen. 
  The 
  roots 
  of 
  the 
  large 
  incisiform 
  teeth 
  extended 
  

   backward 
  as 
  far 
  as 
  the 
  base 
  of 
  the 
  penultimate 
  molars. 
  The 
  

   condyle 
  of 
  the 
  lower 
  jaw 
  is 
  massive 
  and 
  transverse, 
  the 
  articu- 
  

   lation 
  looking 
  upward. 
  Its 
  motion 
  was 
  not 
  limited 
  by 
  a 
  post- 
  

   glenoid 
  process. 
  The 
  posterior 
  margin 
  of 
  the 
  jaw 
  above 
  the 
  

   angle 
  is 
  thickened 
  into 
  a 
  distinct 
  process, 
  which 
  is 
  somewhat 
  

   incurved. 
  The 
  lower 
  jaw 
  is 
  especially 
  deep 
  below 
  the 
  last 
  

   molars, 
  and 
  the 
  entire 
  ramus 
  is 
  robust. 
  The 
  teeth 
  of 
  this 
  genus 
  

   and 
  the 
  great 
  depth 
  of 
  the 
  jaw 
  below 
  the 
  last 
  molars 
  will 
  dis- 
  

   tinguish 
  it 
  from 
  Dryptodon, 
  described 
  by 
  the 
  writer 
  from 
  a 
  

   lower 
  horizon. 
  

  

  The 
  skull 
  of 
  Stylinodon 
  is 
  short 
  and 
  massive. 
  The 
  tem- 
  

   poral 
  fossae 
  are 
  especially 
  large, 
  and 
  are 
  separated 
  above 
  by 
  

   a 
  high 
  ridge. 
  The 
  brain 
  cavity 
  was 
  small. 
  The 
  occipital 
  

   plane 
  is 
  narrow, 
  and 
  the 
  sides 
  converge 
  above 
  and 
  meet 
  at 
  

   the 
  junction 
  with 
  the 
  sagittal 
  crest. 
  The 
  occipital 
  condyles 
  are 
  

   small, 
  and 
  there 
  are 
  no 
  distinct 
  paroccipital 
  processes. 
  

  

  The 
  Vertebrce. 
  

  

  The 
  cervical 
  vertebrae 
  of 
  Stylinodon 
  are 
  well 
  shown 
  in 
  figure 
  

   3, 
  below, 
  which 
  represents 
  the 
  series 
  in 
  the 
  natural 
  position 
  

   essentially 
  as 
  found. 
  The 
  centra 
  are 
  very 
  short, 
  with 
  the 
  

   articular 
  faces 
  nearly 
  flat. 
  The 
  axis 
  has 
  a 
  long 
  neural 
  spine 
  

   directed 
  backward, 
  but 
  the 
  succeeding 
  cervicals 
  have 
  only 
  

   rudimentary 
  spines, 
  as 
  indicated 
  in 
  the 
  figure. 
  

  

  