﻿E. 
  L. 
  Troxell 
  — 
  An 
  Oligocene 
  Camel. 
  387 
  

  

  M 
  2 
  lias 
  a 
  prominent 
  median 
  style 
  and 
  a 
  moderate 
  rib 
  and 
  style 
  

   anteriorly. 
  M 
  1 
  shows 
  scarcely 
  more 
  than 
  the 
  median 
  style 
  and 
  

   the 
  valley 
  in 
  front 
  of 
  it, 
  to 
  break 
  the 
  smooth 
  outer 
  surface. 
  

   On 
  the 
  posterior, 
  internal 
  corner 
  of 
  M 
  3 
  there 
  is 
  a 
  (singular 
  

   ridge 
  or 
  cusp 
  which 
  appears 
  again 
  between 
  the 
  internal 
  lobes 
  

   as 
  a 
  rudimentary, 
  internal, 
  basal 
  pillar 
  ; 
  this 
  is 
  entirely 
  absent 
  

   in 
  Po'ebr 
  other 
  ium 
  generally 
  (Wortman, 
  '98, 
  p. 
  106). 
  

  

  The 
  lower 
  molars, 
  as 
  earlier 
  suggested 
  by 
  Scott, 
  show 
  a 
  

   distinct 
  trend 
  toward 
  hypsodonty 
  ; 
  the 
  enamel 
  on 
  M 
  3 
  especially 
  

   is 
  very 
  deep, 
  reaching 
  to 
  the 
  alveolar 
  border 
  in 
  places. 
  An 
  

   unusual 
  feature 
  is 
  the 
  presence 
  of 
  cement 
  on 
  the 
  lower 
  molars, 
  

   indicating 
  the 
  extreme 
  advancement 
  of 
  these 
  early 
  camels; 
  

   this 
  is 
  further 
  shown 
  by 
  the 
  fact 
  that 
  the 
  lower 
  teeth 
  are 
  

   flattened 
  considerably 
  on 
  the 
  inner 
  side 
  as 
  well 
  as 
  by 
  their 
  

   sub-hypsodonty. 
  

  

  M 
  3 
  has 
  a 
  large 
  third 
  lobe 
  or 
  fifth 
  crescent 
  which 
  occupies 
  

   one 
  fourth 
  of 
  the 
  length 
  of 
  the 
  whole 
  tooth 
  and 
  is 
  over 
  half 
  

   the 
  transverse 
  width 
  of 
  the 
  adjacent 
  lobe. 
  The 
  outer 
  surfaces 
  

   of 
  the 
  lower 
  molars 
  are 
  not 
  rounded, 
  but 
  as 
  shown 
  by 
  the 
  

   enamel 
  border, 
  are 
  angular. 
  

  

  Related 
  forms. 
  — 
  The 
  new 
  specimen 
  is 
  distinguished 
  from 
  

   P. 
  eximium 
  (Hay) 
  by 
  the 
  greater 
  diastemas, 
  especially 
  before 
  

   and 
  after 
  the 
  first 
  premolars, 
  and 
  also 
  by 
  the 
  crowding 
  of 
  the 
  

   lower 
  incisors. 
  The 
  upper 
  canine 
  is 
  relatively 
  much 
  smaller 
  

   and 
  the 
  third 
  upper 
  incisor 
  is 
  very 
  much 
  larger 
  and 
  is 
  canini- 
  

   form. 
  The 
  upper 
  incisors 
  are 
  erect 
  and 
  conical 
  or 
  cylindrical, 
  

   while 
  the 
  lower 
  incisors 
  are 
  procumbent, 
  semi-spatulate 
  and 
  

   crowded 
  together. 
  In 
  P. 
  eximium 
  the 
  incisors, 
  canines 
  and 
  

   first 
  premolars 
  are 
  quite 
  regularly 
  spaced, 
  except 
  that 
  P 
  1 
  is 
  set 
  

   far 
  back, 
  are 
  of 
  uniform 
  size 
  and 
  are 
  somewhat 
  compressed. 
  

  

  The 
  supraoccipital 
  crest 
  in 
  P. 
  labiatum 
  far 
  overhangs 
  the 
  

   condyles, 
  but 
  the 
  crest 
  of 
  the 
  new 
  specimen 
  is 
  only 
  moderately 
  

   extended. 
  Other 
  characters 
  of 
  P. 
  labiatum 
  are 
  : 
  * 
  the 
  otic 
  

   bullae 
  are 
  rounded 
  ; 
  2 
  the 
  lower 
  border 
  of 
  the 
  ramus 
  is 
  rather 
  

   straight, 
  like 
  that 
  of 
  P. 
  %oilsoni; 
  3 
  the 
  alveolar 
  bone 
  encroaches 
  

   on 
  the 
  orbit 
  ; 
  4 
  the 
  paraoccipitals 
  seem 
  to 
  flare 
  widely 
  back- 
  

   and 
  outward 
  ; 
  5 
  M 
  3 
  is 
  set 
  far 
  in 
  front 
  of 
  the 
  ascending 
  portion 
  

   of 
  the 
  ramus 
  ; 
  6 
  in 
  the 
  atlas 
  there 
  is 
  a 
  gap 
  in 
  the 
  posterior 
  

   border 
  of 
  the 
  inferior 
  arch 
  ; 
  7 
  the 
  outer 
  and 
  inner 
  sides 
  of 
  the 
  

   laterial 
  processes 
  are 
  rounded 
  and 
  converge 
  gradually. 
  

  

  On 
  the 
  other 
  hand 
  in 
  Po'ebr 
  other 
  ium 
  andersoni 
  n. 
  sp., 
  2 
  the 
  

   otic 
  bullee 
  are 
  sub-triangular 
  ; 
  2 
  tlie 
  lower 
  border 
  of 
  the 
  ramus 
  

   has 
  a 
  double, 
  reverse 
  curve 
  ; 
  3 
  but 
  little 
  of 
  the 
  maxillary 
  bone 
  

   projects 
  into 
  the 
  region 
  of 
  the 
  orbit 
  ; 
  4 
  the 
  posterior 
  border 
  of 
  

   the 
  paraoccipital 
  stands 
  vertical 
  ; 
  5 
  M 
  3 
  is 
  close 
  to 
  the 
  anterior 
  

   border 
  of 
  the 
  ascending 
  ramus 
  ; 
  6 
  in 
  the 
  atlas 
  there 
  is 
  no 
  gap 
  

   on 
  the 
  inner 
  surface 
  of 
  the 
  lower 
  arch, 
  posterior; 
  7 
  the 
  atlas 
  is 
  

  

  