﻿344 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  VOL.98 
  

  

  The 
  camassial, 
  M2, 
  in 
  M. 
  eothen 
  exhibits 
  more 
  noticeable 
  modi- 
  

   fications 
  than 
  Ml 
  toward 
  a 
  sabertooth 
  specialization. 
  The 
  meta- 
  

   conid 
  is 
  lost, 
  except 
  for 
  a 
  slight 
  rugosity 
  on 
  the 
  posterointernal 
  

   margin 
  of 
  the 
  backward 
  sweeping 
  protocone. 
  The 
  talonid 
  is 
  re- 
  

   duced 
  to 
  little 
  more 
  than 
  a 
  vestige, 
  although 
  its 
  expression 
  is 
  

   somewhat 
  better 
  in 
  the 
  specimen 
  figured 
  by 
  Matthew. 
  ^° 
  The 
  

   tooth 
  is 
  almost 
  catlike 
  in 
  appearance, 
  quite 
  unlike 
  that 
  in 
  Limno- 
  

   cyon 
  or 
  Thinocyon 
  where 
  the 
  carnassial 
  is 
  very 
  much 
  like 
  Mj 
  

   except 
  for 
  its 
  greater 
  size 
  and 
  higher 
  trigonid. 
  In 
  Apataeluncs 
  

   the 
  lower 
  carnassial 
  has 
  almost 
  or 
  quite 
  reached 
  the 
  stage 
  ex- 
  

   hibited 
  by 
  Smilodon 
  in 
  its 
  modification 
  for 
  shearing, 
  but 
  still 
  

   preserving 
  a 
  vestige 
  of 
  its 
  trenchant 
  talonid. 
  

  

  Table 
  1. 
  — 
  Measurements 
  {in 
  millimeters) 
  of 
  skull, 
  mandible, 
  and 
  dentition 
  

   of 
  Machaeroides 
  eothen, 
  U. 
  S. 
  N. 
  M. 
  No. 
  17059 
  

  

  Greatest 
  length 
  of 
  skull 
  from 
  anterior 
  margin 
  of 
  premaxillae 
  to 
  posterior 
  margin 
  

  

  of 
  occipital 
  condyles 
  a 
  135 
  

  

  Distance 
  from 
  anterior 
  margin 
  of 
  premaxillae 
  to 
  posterior 
  narial 
  aperture 
  a 
  65 
  

  

  Greatest 
  depth 
  of 
  maxillae 
  above 
  P' 
  a 
  32 
  

  

  Width 
  of 
  palate 
  between 
  canine 
  alveoli 
  a 
  16 
  

  

  Greatest 
  width 
  of 
  basicranial 
  region 
  across 
  mastoid 
  processes 
  a 
  48 
  

  

  Length 
  of 
  upper 
  dentition 
  from 
  I' 
  to 
  M= 
  inclusive 
  a 
  62 
  

  

  Length 
  of 
  upper 
  dentition 
  from 
  anterior 
  margin 
  of 
  canine 
  alveolus 
  to 
  M' 
  inclusive. 
  ... 
  a 
  66 
  

  

  Width 
  across 
  I' 
  to 
  P 
  inclusive 
  76 
  

  

  Length 
  of 
  cheek 
  tooth 
  series, 
  P' 
  to 
  M- 
  inclusive 
  42 
  

  

  Length 
  of 
  diastema 
  anterior 
  to 
  P' 
  : 
  posterior 
  to 
  P^ 
  3.6 
  ; 
  2.6 
  

  

  Length 
  of 
  premolar 
  series, 
  P^ 
  to 
  P* 
  inclusive 
  30 
  

  

  Length 
  of 
  molar 
  series. 
  M^ 
  to 
  M^ 
  ll.S 
  

  

  Canine 
  — 
  anteroposterior 
  diameter 
  at 
  alveolus: 
  transverse 
  diameter 
  8.6: 
  6 
  

  

  P' 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  8.2: 
  2.1 
  

  

  P'^ 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  5.4: 
  2 
  

  

  P* 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  8 
  : 
  5 
  

  

  P* 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  10 
  : 
  8.2 
  

  

  M' 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  9.4: 
  7.5 
  

  

  M^ 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  3.5: 
  8.1 
  

  

  Length 
  of 
  lower 
  jaw 
  from 
  anterior 
  extremity 
  to 
  condyle 
  92 
  

  

  Depth 
  of 
  symphysis 
  of 
  lower 
  jaw 
  measured 
  along 
  anterior 
  face 
  2< 
  

  

  Depth 
  of 
  flange 
  of 
  lower 
  jaw 
  below 
  diastema 
  between 
  canine 
  and 
  Pi 
  22 
  

  

  Depth 
  of 
  lower 
  jaw 
  below 
  Pj 
  16.6 
  

  

  Depth 
  of 
  lower 
  jaw 
  below 
  Mj 
  16.6 
  

  

  Height 
  of 
  coronoid 
  process 
  above 
  inferior 
  margin 
  of 
  ramus 
  28 
  

  

  Length 
  of 
  lower 
  dentition 
  from 
  anterior 
  margin 
  of 
  canine 
  to 
  Mj 
  inclusive 
  67.6 
  

  

  Length 
  of 
  cheek 
  tooth 
  series. 
  Pi 
  to 
  M2 
  inclusive 
  43.5 
  

  

  Length 
  of 
  diastema 
  anterior 
  to 
  Pi 
  : 
  posterior 
  to 
  Pi 
  8 
  : 
  2 
  

  

  Length 
  of 
  premolar 
  series. 
  Pi 
  to 
  P< 
  inclusive 
  28.8 
  

  

  Length 
  of 
  molar 
  series. 
  Mi 
  and 
  M2 
  16.9 
  

  

  Canine 
  — 
  anteroposterior 
  diameter 
  at 
  cingulum: 
  transverse 
  diameter 
  6.7: 
  3.6 
  

  

  Pi 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  8.6: 
  1.6 
  

  

  P2 
  — 
  anteroposterior 
  diameter: 
  greatest 
  transverse 
  diameter 
  4.7: 
  2 
  

  

  P3 
  — 
  anteroposterior 
  diameter 
  : 
  greatest 
  transverse 
  diameter 
  7.6 
  : 
  3 
  

  

  P4 
  — 
  anteroposterior 
  diameter 
  : 
  greatest 
  transver.se 
  diameter 
  9.1 
  : 
  4 
  

  

  M, 
  — 
  anteroposterior 
  diameter 
  : 
  greatest 
  transverse 
  diameter 
  8.6 
  : 
  4 
  

  

  Ma 
  — 
  anteroposterior 
  diameter 
  : 
  greatest 
  transverse 
  diameter 
  8.7 
  : 
  4.4 
  

  

  Vertebrae. 
  — 
  Among 
  cervical 
  vertebrae 
  preserved 
  of 
  Machae- 
  

  

  i» 
  Matthew, 
  W. 
  D., 
  ibid., 
  fig. 
  71. 
  

  

  