﻿16 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol.67 
  

  

  fragile 
  condition. 
  Hence 
  one 
  can 
  not 
  be 
  certain 
  what 
  modifications 
  

   were 
  present 
  around 
  the 
  ectal 
  orifice 
  of 
  the 
  optic 
  nerve 
  near 
  the 
  base 
  

   of 
  the 
  supraorbital 
  process 
  of 
  the 
  frontal. 
  Both 
  frontals 
  appear 
  to 
  

   have 
  developed 
  thin 
  plates. 
  It 
  is 
  possible 
  that 
  they 
  may 
  have 
  

   curved 
  below 
  the 
  optic 
  nerve 
  in 
  the 
  same 
  manner 
  as 
  in 
  Platanista. 
  

   This 
  point 
  can 
  not 
  be 
  settled 
  on 
  the 
  basis 
  of 
  these 
  two 
  skulls 
  alone. 
  

  

  In 
  the 
  preceding 
  paper 
  8 
  attention 
  was 
  called 
  to 
  the 
  presence 
  of 
  

   a 
  peculiar 
  shelf 
  in 
  the 
  temporal 
  fossa 
  above 
  the 
  upper 
  margin 
  of 
  the 
  

   squamosal. 
  It 
  is 
  now 
  apparent 
  that 
  this 
  shelf 
  was 
  the 
  result 
  of 
  

   crushing 
  and 
  the 
  consequent 
  buckling 
  of 
  the 
  bones 
  involved 
  and 
  that 
  

   it 
  is 
  not 
  comparable 
  with 
  a 
  similar 
  groove 
  on 
  the 
  skull 
  of 
  Platanista. 
  

   The 
  second 
  skull 
  has 
  suffered 
  in 
  the 
  same 
  way 
  on 
  the 
  right 
  side, 
  but 
  

   to 
  a 
  lesser 
  degree. 
  

  

  At 
  the 
  base 
  of 
  the 
  falcate 
  process 
  of 
  the 
  basioccipital 
  and 
  near 
  the 
  

   posterior 
  margin 
  of 
  the 
  alisphenoid 
  is 
  the 
  partially 
  closed 
  ectal 
  

   orifice 
  of 
  the 
  canal 
  for 
  the 
  carotid 
  artery. 
  The 
  mandibular 
  branch 
  of 
  

   the 
  fifth 
  cranial 
  nerve 
  issues 
  through 
  a 
  cleft 
  on 
  the 
  posterior 
  border 
  

   of 
  the 
  alsiphenoid 
  at 
  a 
  point 
  11 
  mm. 
  external 
  to 
  the 
  orifice 
  of 
  the 
  

   carotid 
  canal 
  and 
  on 
  its 
  forward 
  and 
  outward 
  course 
  crosses 
  the 
  

   ventral 
  face 
  of 
  this 
  bone, 
  finally 
  emerging 
  in 
  the 
  temporal 
  fossa 
  

   through 
  the 
  foramen 
  ovale. 
  

  

  A 
  postero-external 
  process 
  of 
  the 
  alisphenoid 
  projects 
  backward, 
  

   meeting 
  the 
  squamosal 
  along 
  its 
  external 
  border, 
  abutting 
  against 
  

   the 
  exoccipital 
  posteriorly, 
  and 
  uniting 
  with 
  the 
  underlying 
  process 
  

   of 
  the 
  basioccipital 
  internally. 
  The 
  alisphenoid 
  and 
  the 
  above 
  

   mentioned 
  bones 
  form 
  the 
  fossa 
  in 
  which 
  periotic 
  and 
  tympanic 
  

   bones 
  are 
  lodged. 
  A 
  small 
  foramen 
  pierces 
  the 
  alisphenoid 
  above 
  

   the 
  anterior 
  process 
  of 
  the 
  periotic. 
  Two 
  large 
  foramina 
  appear 
  in 
  

   this 
  fossa 
  above 
  and 
  internal 
  to 
  the 
  jugular 
  incisure. 
  The 
  ectal 
  orifice 
  

   of 
  the 
  internal 
  foramen 
  is 
  situated 
  internal 
  to 
  the 
  jugular 
  incisure; 
  it 
  

   opens 
  at 
  the 
  base 
  and 
  near 
  the 
  posterior 
  margin 
  of 
  the 
  falcate 
  process 
  

   of 
  the 
  basioccipital. 
  This 
  foramen 
  probably 
  represents 
  the 
  com- 
  

   partment 
  for 
  the 
  nerves 
  in 
  the 
  foramen 
  lacerum 
  posterius. 
  The 
  

   external 
  foramen 
  is 
  partially 
  inclosed 
  by 
  the 
  exoccipital 
  and 
  may 
  

   afford 
  a 
  passage 
  for 
  the 
  jugular 
  vein. 
  The 
  foramina 
  within 
  the 
  

   tympano-periotic 
  fossa 
  have 
  the 
  same 
  general 
  arrangement 
  as 
  on 
  one 
  

   skull 
  of 
  EurJiinodelpMs 
  bossi 
  9 
  which 
  was 
  also 
  obtained 
  from 
  the 
  

   Calvert 
  formation. 
  In 
  skulls 
  of 
  Platanista, 
  Inia, 
  and 
  Lipotes, 
  a 
  large 
  

   fissure 
  occupied 
  the 
  area 
  corresponding 
  to 
  the 
  tympano-periotic 
  fossa 
  

   on 
  the 
  Zarliachis 
  skull. 
  

  

  s 
  Ki'llogg, 
  R., 
  Proc. 
  U. 
  S. 
  Nat. 
  Mus., 
  vol. 
  63, 
  pp. 
  18-19. 
  1924. 
  

  

  • 
  R. 
  Kellogg, 
  On 
  the 
  occurrence 
  of 
  remains 
  of 
  fossil 
  porpoises 
  of 
  the 
  genus 
  Eurhinodelphis 
  in 
  North 
  

   America. 
  Proc. 
  U. 
  S. 
  Nat. 
  Mus., 
  vol. 
  66, 
  publ. 
  2563, 
  pi. 
  5. 
  1925. 
  

  

  