﻿432 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  io3 
  

  

  cylindrodon 
  appears 
  to 
  be 
  restricted 
  to 
  the 
  mountains 
  in 
  the 
  Lower 
  

   Ohgocene 
  but 
  did 
  not 
  survive 
  into 
  the 
  Middle 
  Oligocene. 
  Eutypomys, 
  

   a 
  large 
  active 
  form, 
  is 
  common 
  to 
  both 
  Provinces 
  in 
  the 
  Lower 
  Oli- 
  

   gocene. 
  Both 
  genera 
  of 
  the 
  Eomyidae 
  are 
  common 
  to 
  both 
  

   Provinces 
  in 
  both 
  the 
  Lower 
  and 
  Middle 
  Oligocene. 
  

  

  Lagomorpha. 
  — 
  Megalagus 
  and 
  Paleolagus 
  are 
  common 
  to 
  both 
  

   areas. 
  The 
  species 
  are 
  distinct 
  in 
  Megalagus 
  and 
  probably 
  also 
  in 
  

   Paleolagus. 
  Desmatolagus, 
  as 
  with 
  Domnina 
  and 
  Ischyromys, 
  appears 
  

   to 
  be 
  restricted 
  to 
  the 
  mountains 
  in 
  the 
  Lower 
  Oligocene 
  but 
  is 
  repre- 
  

   sented 
  in 
  the 
  Middle 
  Oligocene 
  of 
  the 
  plains. 
  

  

  Carnivora. 
  — 
  The 
  creodonts 
  are 
  rare 
  in 
  the 
  Lower 
  Oligocene 
  of 
  both 
  

   Provinces 
  and 
  consequently 
  are 
  useless 
  for 
  this 
  type 
  of 
  study. 
  

   Daphoenocyon 
  and 
  Parictis 
  are 
  common 
  to 
  both 
  areas 
  and 
  no 
  specific 
  

   separation 
  appears 
  possible. 
  Hesperocyon 
  is 
  common 
  to 
  both 
  

   Provinces 
  but 
  the 
  species 
  are 
  distinct. 
  Plesictis 
  appears 
  to 
  be 
  restric- 
  

   ted 
  to 
  the 
  Plains 
  Province 
  and 
  Paleogale 
  appears 
  to 
  be 
  restricted 
  to 
  

   the 
  mountains 
  in 
  the 
  Lower 
  Oligocene 
  but 
  is 
  well 
  represented 
  on 
  the 
  

   plains 
  in 
  the 
  Middle 
  Ohgocene. 
  To 
  the 
  best 
  of 
  my 
  knowledge, 
  not 
  

   even 
  fragmentary 
  evidence 
  of 
  the 
  fehds 
  has 
  been 
  found 
  in 
  any 
  of 
  the 
  

   Lower 
  Oligocene 
  deposits 
  of 
  the 
  intermountain 
  basins. 
  With 
  such 
  

   complete 
  negative 
  evidence 
  for 
  an 
  area 
  as 
  extensively 
  collected 
  as 
  

   Pipestone 
  Springs, 
  it 
  seems 
  reasonable 
  to 
  infer 
  that 
  the 
  mountains 
  

   were 
  climatically 
  unsuited 
  to 
  the 
  Lower 
  Oligocene 
  felids. 
  

  

  Perissodactyla. 
  — 
  Mesohippus 
  is 
  common 
  to 
  both 
  Provinces 
  but 
  

   the 
  Lower 
  Oligocene 
  species 
  have 
  not 
  been 
  reviewed 
  since 
  the 
  time 
  

   it 
  was 
  considered 
  an 
  act 
  of 
  the 
  greatest 
  discourtesy 
  to 
  place 
  

   someone 
  else's 
  species 
  in 
  synonomy. 
  Consequently 
  the 
  data 
  furnished 
  

   by 
  the 
  species 
  of 
  this 
  genus 
  are 
  not 
  suitable 
  for 
  this 
  study. 
  The 
  

   remains 
  of 
  the 
  Rhinocerotidae 
  from 
  the 
  Mountain 
  Province 
  are 
  

   fragmentary 
  but 
  Hyracodon 
  and 
  Caenopus 
  were 
  common 
  to 
  both 
  

   Provinces. 
  The 
  remains 
  of 
  the 
  Brontotheroidea 
  are 
  too 
  fragmentary 
  

   for 
  generic 
  identification. 
  Colodon 
  is 
  common 
  to 
  both 
  areas 
  but 
  its 
  

   scarcity 
  makes 
  it 
  unsuited 
  for 
  this 
  study. 
  

  

  Artiodactyla. 
  — 
  Although 
  the 
  Leptochoeridae 
  are 
  common 
  to 
  both 
  

   areas, 
  their 
  remains 
  are 
  too 
  rare 
  to 
  be 
  suitable 
  for 
  this 
  study. 
  The 
  

   Entelodontidae 
  appear 
  to 
  be 
  restricted 
  to 
  the 
  plains, 
  and, 
  like 
  the 
  

   felids, 
  seem 
  to 
  have 
  found 
  the 
  mountains 
  climatically 
  inhospitable. 
  

   The 
  Tayussuidae 
  are 
  unknown 
  in 
  the 
  Mountain 
  Province 
  but 
  are 
  also 
  

   rare 
  in 
  the 
  plains 
  and 
  consequently 
  unsuited 
  for 
  this 
  study. 
  Likewise, 
  

   the 
  Botlu-iodontidae 
  are 
  unknown 
  in 
  the 
  mountains 
  and 
  are 
  rare 
  on 
  

   the 
  plains. 
  The 
  remains 
  of 
  the 
  Merycoidodontidae 
  in 
  the 
  Mountain 
  

   Province 
  are 
  very 
  fragmentary 
  and 
  useless 
  for 
  this 
  type 
  of 
  study. 
  Of 
  

   the 
  Hypertragulidae, 
  only 
  one 
  genus, 
  Leptomeryx, 
  is 
  common 
  to 
  the 
  

   two 
  areas 
  but 
  no 
  specific 
  separation 
  between 
  the 
  two 
  regions 
  can 
  be 
  

  

  