﻿582 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.44. 
  

  

  In 
  the 
  upper 
  jaw 
  the 
  first 
  and 
  second 
  incisors 
  have 
  a 
  deep 
  cup; 
  

   the 
  third 
  incisor 
  has 
  the 
  cup 
  widely 
  open 
  on 
  the 
  hinder 
  face 
  of 
  the 
  

   tooth. 
  The 
  canines 
  were 
  just 
  emerging 
  from 
  the 
  bone. 
  

  

  In 
  the 
  lower 
  jaw 
  the 
  first 
  and 
  second 
  incisors 
  are 
  a 
  little 
  worn, 
  

   while 
  the 
  third 
  had 
  just 
  begun 
  to 
  be 
  worn. 
  The 
  second 
  has 
  the 
  

   hinder 
  border 
  of 
  its 
  cup 
  a 
  little 
  notched; 
  while 
  the 
  third 
  is 
  widely 
  

   open, 
  as 
  in 
  the 
  same 
  tooth 
  of 
  the 
  type 
  specimen. 
  The 
  canines 
  were 
  

   just 
  commg 
  through 
  the 
  bone 
  very 
  close 
  to 
  the 
  third 
  canine. 
  From 
  

   the 
  figure 
  of 
  the 
  lower 
  teeth 
  (fig, 
  21) 
  it 
  wUl 
  be 
  seen 
  that 
  the 
  valley 
  

   at 
  the 
  middle 
  of 
  the 
  outer 
  face 
  does 
  not, 
  or 
  hardly 
  at 
  aU, 
  push 
  itself 
  

   in 
  between 
  the 
  adjacent 
  ends 
  of 
  the 
  longitudinal 
  valleys. 
  These 
  

   teeth 
  differ 
  but 
  slightly 
  from 
  those 
  of 
  figure 
  5. 
  

  

  Measurements 
  of 
  upper 
  and 
  lower 
  jaws. 
  

  

  mm. 
  

  

  Height 
  of 
  maxilla 
  above 
  pm.* 
  105 
  

  

  Height 
  of 
  maxilla 
  above 
  pm.- 
  71 
  

  

  Width 
  of 
  upper 
  jaw 
  at 
  i.' 
  76 
  

  

  From 
  front 
  of 
  pm.^ 
  to 
  canine 
  (diastema) 
  66 
  

  

  From 
  front 
  of 
  pm.'^ 
  to 
  front 
  of 
  premaxilla 
  137 
  

  

  Height 
  of 
  lower 
  jaw 
  at 
  rear 
  of 
  7n.^ 
  123 
  

  

  Height 
  of 
  lower 
  jaw 
  at 
  rear 
  of 
  pm.o 
  70 
  

  

  Width 
  of 
  lower 
  jaw 
  at 
  i.3 
  65 
  

  

  Distance 
  between 
  pm.2 
  and 
  i.3 
  90 
  

  

  Length 
  of 
  symphysis 
  of 
  lower 
  jaw 
  82 
  

  

  It 
  may 
  be 
  of 
  value 
  to 
  describe 
  some 
  milk 
  teeth 
  which 
  appear 
  to 
  

   belong 
  to 
  this 
  species. 
  In 
  the 
  collection 
  of 
  the 
  American 
  Museum 
  

   of 
  Natural 
  History 
  is 
  a 
  part 
  of 
  a 
  right 
  maxilla 
  which 
  contains 
  the 
  

   second, 
  third, 
  and 
  fourth 
  milk 
  molars 
  (fig. 
  22). 
  It 
  has 
  the 
  col- 
  

   lector's 
  number 
  81. 
  The 
  bases 
  of 
  the 
  teeth 
  are 
  concealed 
  and 
  con- 
  

   sequently 
  one 
  can 
  determine 
  only 
  approximately 
  the 
  height 
  of 
  the 
  

   crown. 
  This 
  appears 
  to 
  be 
  about 
  45 
  mm. 
  The 
  state 
  of 
  wear 
  of 
  

   the 
  teeth 
  indicates 
  a 
  colt 
  about 
  6 
  months 
  old. 
  At 
  the 
  stage 
  of 
  wear 
  

   in 
  which 
  the 
  teeth 
  are 
  found, 
  the 
  post-protoconal 
  valley 
  opens 
  into 
  

   the 
  anterior 
  lake. 
  The 
  fourth 
  mUk 
  molar 
  is 
  but 
  little 
  worn. 
  Prob- 
  

   ably 
  about 
  3 
  millimeters 
  ought 
  on 
  this 
  account 
  to 
  be 
  added 
  to 
  its 
  

   width 
  as 
  given 
  below. 
  

  

  Measurements 
  of 
  upper 
  milk 
  molars. 
  

  

  As 
  is 
  well 
  known, 
  the 
  milk 
  molars 
  are 
  distinguished 
  from 
  the 
  

   premolars 
  which 
  succeed 
  them 
  by 
  their 
  relatively 
  low 
  crowns. 
  It 
  

  

  