﻿588 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.44. 
  

  

  Measurements 
  of 
  the 
  lower 
  teeth. 
  

  

  mm. 
  

  

  Length 
  of 
  premolar-molar 
  series, 
  pm.j-m.j, 
  inclusive 
  175 
  

  

  Length, 
  of 
  premolar 
  series 
  89 
  

  

  Length 
  of 
  molar 
  scries 
  86 
  

  

  Pm.2, 
  length 
  32 
  

  

  width 
  15 
  

  

  Pm.3, 
  length 
  28 
  

  

  width 
  : 
  16.5 
  

  

  Pm.4, 
  length 
  - 
  29 
  

  

  width 
  16 
  

  

  Jf.i, 
  length 
  25 
  

  

  width 
  15 
  

  

  M.2, 
  length 
  26 
  

  

  width 
  14 
  

  

  M.3, 
  length 
  30 
  

  

  width 
  14 
  

  

  In 
  the 
  United 
  States 
  National 
  Museum 
  there 
  is 
  a 
  palate 
  which 
  

   presents 
  the 
  complete 
  upper 
  dentition 
  of 
  a 
  horse 
  which 
  seems 
  to 
  

   have 
  belonged 
  to 
  the 
  species 
  here 
  described. 
  Its 
  catalogue 
  number 
  

   is 
  4991, 
  and 
  the 
  specimen 
  was 
  collected 
  by 
  J. 
  B. 
  Hatcher 
  in 
  1886, 
  

   near 
  Hay 
  Springs, 
  Nebraska. 
  Figure 
  27 
  shows 
  the 
  dentition 
  of 
  the 
  

   left 
  side. 
  

  

  The 
  following 
  measurements 
  are 
  given 
  in 
  order 
  to 
  show 
  what 
  

   seems 
  to 
  be 
  the 
  essential 
  agreement 
  of 
  the 
  specimen 
  with 
  the 
  type 
  

   and 
  at 
  the 
  same 
  time 
  some 
  deviations 
  therefrom: 
  

  

  Measurements 
  of 
  skull 
  and 
  teeth. 
  

  

  mm. 
  

  

  From 
  middle 
  of 
  incisive 
  border 
  to 
  line 
  joining 
  rear 
  of 
  m.^ 
  of 
  the 
  two 
  sides 
  275 
  

  

  From 
  middle 
  of 
  incisive 
  border 
  to 
  line 
  joining 
  front 
  of 
  pm.'^ 
  of 
  the 
  two 
  sides. 
  . 
  . 
  117 
  

  

  Width 
  of 
  premaxillae 
  at 
  base 
  of 
  i.^ 
  70 
  

  

  Width 
  of 
  palate 
  between 
  c. 
  and 
  pm.^, 
  narrowest 
  40 
  

  

  Width 
  at 
  border 
  of 
  nasal 
  opening 
  just 
  above 
  last 
  69 
  

  

  Width 
  of 
  face 
  opposite 
  middle 
  of 
  pm.* 
  136 
  

  

  Width 
  of 
  face 
  opposite 
  m.^ 
  180 
  

  

  Width 
  of 
  posterior 
  nares 
  51 
  

  

  Length, 
  premolar-molar 
  series 
  158 
  

  

  Length, 
  premolar 
  series 
  87 
  

  

  Length, 
  molar 
  series 
  72 
  

  

  Pm.2, 
  length 
  36 
  

  

  width 
  23 
  

  

  protocone 
  H 
  

  

  Pm.3, 
  length 
  25 
  

  

  width 
  27 
  

  

  protocone 
  14 
  

  

  Pm.^ 
  length 
  25 
  

  

  width 
  25.4 
  

  

  protocone 
  15 
  

  

  M.\ 
  length 
  23 
  

  

  width 
  25 
  

  

  protocone 
  14 
  

  

  