﻿576 
  

  

  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  

  

  to 
  be 
  hitherto 
  without 
  a 
  name, 
  is 
  given 
  the 
  title 
  Equus 
  littoralis. 
  The 
  

   tooth 
  represented 
  by 
  figure 
  17 
  is 
  taken 
  as 
  the 
  typp, 
  but 
  that 
  of 
  figure 
  

   18 
  certainly 
  belonged 
  to 
  the 
  same 
  species, 
  possibly 
  to 
  the 
  same 
  indi- 
  

   vidual. 
  The 
  anterior 
  half 
  of 
  the 
  outer 
  wall 
  of 
  enamel 
  of 
  the 
  type 
  has 
  

   been 
  split 
  off. 
  

  

  The 
  following 
  are 
  the 
  dimensions 
  of 
  these 
  teeth 
  : 
  

  

  These 
  teeth 
  seem 
  somewhat 
  more 
  curved 
  than 
  those 
  of 
  E. 
  leidyi'. 
  

   A 
  curved 
  line 
  representing 
  the 
  hinder 
  border 
  of 
  the 
  outer 
  face 
  has 
  its 
  

   chord 
  62 
  mm. 
  long, 
  and 
  its 
  middle 
  point 
  is 
  about 
  6.5 
  mm. 
  distant 
  from 
  

   the 
  chord. 
  The 
  chord 
  of 
  the 
  inner 
  face 
  is 
  53 
  mm. 
  long 
  and 
  the 
  middle 
  

   point 
  of 
  the 
  face 
  is 
  7 
  mm. 
  distant 
  from 
  the 
  chord. 
  The 
  post-pro 
  toconal 
  

   valley, 
  as 
  represented 
  by 
  the 
  two 
  teeth 
  at 
  hand, 
  is 
  narrow 
  and 
  falls 
  

   much 
  short 
  of 
  reaching 
  half 
  way 
  to 
  the 
  median 
  style 
  of 
  the 
  outer 
  face 
  

   of 
  the 
  tooth. 
  No 
  lower 
  teeth 
  are 
  known 
  that 
  agree 
  in 
  size 
  with 
  the 
  

   upper 
  teeth 
  described 
  above. 
  

  

  Mr. 
  Gidley 
  ^ 
  states 
  that 
  there 
  are 
  in 
  the 
  American 
  Museum 
  of 
  

   Natural 
  History 
  a 
  small 
  tooth 
  from 
  Peace 
  Creek, 
  Florida, 
  and 
  another 
  

   from 
  Lookout 
  Mountain, 
  Tennessee. 
  It 
  is 
  suggested 
  that 
  these 
  may 
  

   belong 
  to 
  Owen's 
  Equus 
  tau, 
  a 
  species 
  described 
  from 
  the 
  Valley 
  of 
  

   Mexico. 
  The 
  present 
  writfer 
  has 
  not 
  seen 
  these 
  teeth, 
  but 
  from 
  

   Gidley's 
  measurements, 
  taken 
  from 
  Owen's 
  figures, 
  as 
  well 
  as 
  from 
  

   Owen's 
  statement, 
  it 
  is 
  to 
  be 
  noted 
  that 
  in 
  all 
  the 
  premolars 
  and 
  

   molars 
  the 
  length 
  of 
  the 
  grinding 
  surface 
  is 
  greater 
  than 
  the 
  width 
  ; 
  

   whereas, 
  in 
  the 
  teeth 
  of 
  E. 
  littoralis, 
  the 
  width 
  is 
  greater 
  than 
  the 
  

   length. 
  Moreover, 
  Owen's 
  figure 
  indicates 
  no 
  such 
  complexity 
  of 
  the 
  

   enamel 
  in 
  E. 
  tau 
  as 
  characterizes 
  the 
  teeth 
  of 
  E. 
  littoralis. 
  

  

  EQUUS 
  NIOBRARENSIS, 
  new 
  species. 
  

  

  Type. 
  — 
  A 
  nearly 
  complete 
  skull 
  belonging 
  to 
  the 
  United 
  States 
  

   National 
  Museum 
  and 
  having 
  the 
  catalogue 
  number 
  4999. 
  Found 
  

   in 
  supposed 
  lower 
  Pleistocene 
  deposits, 
  at 
  Hay 
  Springs, 
  Nebraska. 
  

  

  Characterized 
  by 
  teeth 
  of 
  rather 
  large 
  size, 
  the 
  length 
  of 
  the 
  grind- 
  

   ing 
  surface 
  of 
  the 
  first 
  molar 
  being 
  about 
  27 
  mm., 
  the 
  width 
  about 
  

   the 
  same. 
  Enamel 
  of 
  the 
  lakes 
  of 
  rather 
  simple 
  pattern. 
  

  

  The 
  skull 
  to 
  which 
  the 
  name 
  Equus 
  niohrarensis 
  is 
  here 
  given 
  was 
  

   discovered 
  in 
  1886 
  by 
  Prof. 
  J. 
  B. 
  Hatcher, 
  along 
  the 
  Niobrara 
  River, 
  

   near 
  Hay 
  Springs, 
  Nebraska. 
  When 
  found 
  it 
  was 
  in 
  a 
  more 
  or 
  less 
  

   broken 
  condition, 
  and 
  it 
  was 
  afterwards 
  put 
  in 
  its 
  present 
  state 
  by 
  Mr. 
  

   Alban 
  Stewart. 
  As 
  shown 
  by 
  plate 
  69, 
  figs. 
  2,3, 
  and 
  plate 
  70, 
  the 
  bone 
  is 
  

  

  1 
  Bull. 
  Amer. 
  Mus. 
  Nat. 
  Hist: 
  vol. 
  14, 
  p. 
  121. 
  

  

  