﻿14 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  67 
  

  

  of 
  the 
  left 
  glenoid 
  fossa, 
  has 
  been 
  much 
  augmented 
  ,by 
  the 
  rostral 
  

   twist. 
  In 
  fact 
  the 
  latter 
  is 
  so 
  great 
  that 
  the 
  mandible 
  has 
  resisted 
  

   it, 
  through 
  the 
  interlocking 
  of 
  the 
  teeth. 
  Thus, 
  the 
  mandibular 
  

   canines 
  have 
  been 
  forced 
  to 
  incline 
  toward 
  the 
  left, 
  while 
  the 
  max- 
  

   illary 
  canines 
  and 
  lateral 
  incisors 
  have 
  been 
  pushed 
  toward 
  the 
  

   right. 
  The 
  result 
  is 
  that 
  although 
  the 
  rostrum 
  as 
  a 
  whole 
  turns 
  

   strongly 
  to 
  the 
  left, 
  the 
  anterior 
  portion 
  of 
  its 
  alveolar 
  border 
  exhibits 
  

   a 
  slightly 
  dextral 
  counter 
  twist. 
  The 
  mandible 
  reflects 
  the 
  varied 
  

   stresses 
  in 
  a 
  form 
  difficult 
  to 
  describe 
  with 
  accuracy, 
  but 
  to 
  attempt 
  

   to 
  do 
  so 
  is 
  hardly 
  necessary. 
  

  

  Another 
  skull 
  of 
  Eumeto'pias 
  jubata 
  showing 
  some 
  asymmetry 
  was 
  

   also 
  discovered. 
  This 
  is 
  No. 
  131895 
  of 
  the 
  United 
  States 
  Biological 
  

   Survey 
  collection, 
  and 
  bears 
  the 
  data 
  " 
  9 
  , 
  California, 
  Santa 
  Cruz 
  Id., 
  

   W. 
  J. 
  Hockmeier, 
  4386X." 
  It 
  is 
  of 
  an 
  adult, 
  though 
  not 
  aged 
  

   individual 
  (pi. 
  8). 
  The 
  original 
  cause 
  leading 
  to 
  present 
  asymmetry 
  

   was 
  a 
  pathological 
  condition 
  of 
  the 
  left 
  auditory 
  and 
  petrous 
  tem- 
  

   poral, 
  which 
  are 
  now 
  misshapen, 
  with 
  rough 
  surfaces, 
  and 
  a 
  large 
  

   perforation 
  inferiorly. 
  An 
  abscess 
  probably 
  constituted 
  the 
  original 
  

   cause. 
  The 
  result 
  has 
  been 
  a 
  stunting 
  of 
  the 
  region 
  involved, 
  and 
  

   the 
  distance 
  from 
  craniad 
  of 
  the 
  glenoid 
  fossa 
  to 
  the 
  paroccipital 
  

   process 
  is 
  7 
  mm. 
  less 
  upon 
  this 
  side 
  than 
  the 
  right. 
  The 
  zygomatic 
  

   arches 
  are 
  also 
  involved, 
  probably 
  through 
  lack 
  of 
  normal 
  growth 
  of 
  

   this 
  process 
  of 
  the 
  left 
  squamosal, 
  for 
  the 
  left 
  arch 
  is 
  about 
  6 
  mm. 
  

   shorter 
  than 
  the 
  other. 
  This, 
  in 
  turn, 
  has 
  evidently 
  been 
  instru- 
  

   mental 
  in 
  limiting 
  the 
  growth 
  of 
  the 
  anterior 
  portion 
  of 
  the 
  tempo- 
  

   ral 
  muscle, 
  as 
  clearly 
  shown 
  by 
  the 
  differences 
  in 
  the 
  development 
  

   of 
  the 
  supraorbital 
  processes 
  and 
  the 
  ridging 
  between 
  them. 
  The 
  

   remainder 
  of 
  the 
  temporal 
  fossae 
  do 
  not 
  show 
  any 
  appreciable 
  

   disparity, 
  however. 
  

  

  Very 
  slight 
  asymmetry 
  exhibited 
  by 
  the 
  posterior 
  half 
  of 
  the 
  ros- 
  

   trum 
  is 
  probably 
  due 
  to 
  dissimilarity 
  in 
  the 
  development 
  of 
  the 
  two 
  

   zygomatic 
  arches 
  and 
  the 
  temporals, 
  while 
  the 
  decided 
  sinistral 
  twist 
  

   of 
  the 
  rostral 
  extremity 
  is 
  attributable, 
  through 
  the 
  interlocking 
  of 
  

   the 
  canines, 
  to 
  the 
  displacement 
  of 
  the 
  left 
  glenoid 
  fossa, 
  and 
  hence, 
  

   the 
  mandible. 
  

  

  An 
  interesting 
  point 
  which 
  can 
  hardly 
  be 
  explained 
  entirely 
  by 
  the 
  

   foregoing 
  conditions 
  is 
  asymmetry 
  in 
  the 
  occipital 
  region. 
  This 
  is 
  

   precisely 
  the 
  opposite 
  of 
  what 
  might 
  be 
  expected, 
  for 
  the 
  distance 
  

   between 
  the 
  foraminal 
  margin 
  of 
  the 
  occipital 
  condyle 
  and 
  the 
  paroc- 
  

   cipital 
  process 
  is, 
  upon 
  the 
  left, 
  61, 
  and 
  on 
  the 
  right, 
  54 
  mm. 
  It 
  is 
  

   due 
  to 
  growth 
  of 
  the 
  left 
  paroccipital 
  process 
  and 
  the 
  exoccipital 
  

   rather 
  than 
  to 
  displacement 
  of 
  the 
  foramen 
  magnum. 
  One 
  might 
  

   hazard 
  the 
  opinion 
  that 
  it 
  is 
  the 
  result 
  of 
  a 
  compensating 
  development 
  

   of 
  the 
  attached 
  muscles, 
  as 
  the 
  digastric, 
  or 
  to 
  some 
  pathological 
  

  

  