﻿abt. 
  28 
  SKULL 
  OF 
  ZARHACHIS 
  FLAGELLATOR 
  KELLOGG 
  9 
  

  

  least 
  half 
  of 
  the 
  upper 
  border 
  of 
  the 
  anterior 
  wall 
  of 
  each 
  nasal 
  

   passage 
  is 
  contributed 
  by 
  the 
  vomer 
  whose 
  upper 
  margin 
  rolls 
  over 
  

   or 
  is 
  folded 
  outward 
  so 
  that 
  it 
  meets 
  the 
  maxilla 
  slightly 
  external 
  to 
  

   the 
  mid 
  line 
  of 
  the 
  nasal 
  passage. 
  The 
  peculiar 
  curvature 
  of 
  the 
  

   lateral 
  walls 
  of 
  the 
  trough 
  of 
  the 
  vomer 
  around 
  the 
  upper 
  borders 
  of 
  

   the 
  nasal 
  passages 
  does 
  not 
  appear 
  to 
  be 
  duplicated 
  in 
  any 
  of 
  the 
  

   living 
  toothed 
  whales. 
  The 
  maxilla 
  contributes 
  the 
  outer 
  wall 
  and 
  

   about 
  one-half 
  of 
  the 
  dorsal 
  border 
  of 
  the 
  anterior 
  wall. 
  Inferiorly, 
  

   the 
  palatine 
  extends 
  upward 
  in 
  each 
  nasal 
  passage 
  for 
  a 
  distance 
  

   equivalent 
  to 
  about 
  three-fourths 
  of 
  the 
  depth 
  of 
  the 
  anterior 
  wall 
  

   and 
  is 
  inserted 
  between 
  the 
  maxilla 
  and 
  vomer 
  in 
  the 
  shape 
  of 
  a 
  

   subtriangular 
  wedge. 
  The 
  dorsal 
  margin 
  of 
  the 
  surface 
  of 
  the 
  

   palatine 
  which 
  takes 
  part 
  in 
  the 
  formation 
  of 
  the 
  nasal 
  passage 
  is 
  

   emarginate. 
  

  

  In 
  front 
  of 
  the 
  nasal 
  passages, 
  the 
  trough 
  of 
  the 
  vomer 
  assumes 
  the 
  

   shape 
  characteristic 
  of 
  most 
  dolphins. 
  At 
  the 
  level 
  of 
  the 
  anterior 
  

   margin 
  of 
  the 
  nasal 
  passages, 
  the 
  greatest 
  depth 
  of 
  the 
  trough 
  of 
  the 
  

   vomer 
  is 
  98 
  mm., 
  but 
  at 
  a 
  point 
  180 
  mm. 
  in 
  front 
  of 
  these 
  passages, 
  

   it 
  does 
  not 
  measure 
  more 
  than 
  25 
  mm. 
  in 
  depth. 
  For 
  a 
  distance 
  of 
  

   75 
  mm. 
  in 
  front 
  of 
  the 
  nasal 
  passages, 
  the 
  dorsal 
  margins 
  of 
  the 
  lateral 
  

   walls 
  of 
  the 
  vomer 
  slope 
  forward 
  and 
  downward 
  at 
  a 
  very 
  steep 
  angle. 
  

   This 
  may 
  be 
  associated 
  with 
  the 
  mesial 
  depression 
  of 
  the 
  internal 
  

   borders 
  of 
  the 
  premaxillae 
  behind 
  and 
  in 
  front 
  of 
  the 
  premaxillary 
  

   foramina. 
  Anterior 
  to 
  this 
  depression, 
  the 
  reduction 
  of 
  the 
  lateral 
  

   walls 
  of 
  the 
  vomer 
  is 
  rather 
  gradual. 
  From 
  a 
  ventral 
  view, 
  the 
  vomer 
  

   is 
  seen 
  to 
  be 
  split 
  along 
  the 
  mid 
  line 
  of 
  the 
  axial 
  ridge, 
  but 
  this 
  may 
  be 
  

   abnormal. 
  The 
  axial 
  ridge 
  is 
  wedged 
  in 
  between 
  the 
  opposing 
  faces 
  

   of 
  the 
  maxillae 
  and 
  in 
  correlation 
  with 
  this 
  compression 
  and 
  with 
  the 
  

   slope 
  of 
  the 
  internal 
  surface 
  of 
  the 
  maxilla, 
  the 
  floor 
  of 
  the 
  mesorostral 
  

   gutter 
  is 
  rather 
  narrow 
  posteriorly 
  and 
  it 
  becomes 
  so 
  narrow 
  about 
  140 
  

   mm. 
  in 
  front 
  of 
  the 
  nasal 
  passages 
  that 
  it 
  would 
  appear 
  V 
  _sna 
  ped 
  in 
  

   cross 
  section. 
  The 
  lateral 
  border 
  of 
  the 
  trough 
  of 
  the 
  vomer 
  rolls 
  

   over 
  and 
  is 
  overspread 
  by 
  the 
  thin 
  margin 
  of 
  the 
  horizontal 
  plate 
  of 
  

   the 
  premaxilla, 
  which 
  overhangs 
  the 
  mesorostral 
  gutter. 
  

  

  Posterior 
  view. 
  — 
  The 
  back 
  of 
  the 
  brain 
  case 
  (pi. 
  3) 
  has 
  been 
  crushed 
  

   in 
  a 
  dorso-ventral 
  direction 
  and 
  the 
  extent 
  of 
  this 
  crushing 
  is 
  best 
  

   illustrated 
  on 
  the 
  posterior 
  face 
  of 
  the 
  skull. 
  The 
  lower 
  half 
  of 
  the 
  

   supraoccipital 
  was 
  too 
  thin 
  to 
  support 
  the 
  great 
  weight 
  of 
  the 
  sedi- 
  

   ments 
  which 
  overlay 
  the 
  skull, 
  and 
  the 
  bone 
  fractured 
  in 
  many 
  direc- 
  

   tions. 
  A 
  portion 
  of 
  the 
  supraoccipital 
  was 
  thrust 
  downward 
  into 
  

   the 
  foramen 
  magnum 
  and 
  it 
  also 
  buckled 
  inward 
  above 
  the 
  condyles. 
  

   The 
  displacement 
  or 
  amount 
  of 
  crushing 
  at 
  the 
  center 
  of 
  the 
  foramen 
  

   magnum 
  may 
  equal 
  20 
  or 
  25 
  mm. 
  Another 
  consequence 
  of 
  this 
  

   crushing 
  is 
  shown 
  by 
  the 
  buckling 
  of 
  the 
  parietals 
  and 
  frontals 
  in 
  the 
  

   temporal 
  fossae. 
  

  

  54286— 
  26f 
  2 
  

  

  