﻿Vol. 
  53-] 
  

  

  OP 
  THE 
  SKULL 
  OP 
  A 
  PLIOSATJR. 
  

  

  179' 
  

  

  the 
  latter 
  element 
  runs 
  forward 
  in 
  the 
  form 
  of 
  an 
  elongated 
  spear- 
  

   head, 
  of 
  which 
  the 
  postero-lateral 
  borders 
  form 
  the 
  inner 
  margin 
  of 
  the 
  

   posterior 
  palatine 
  vacuities, 
  while 
  the 
  antero 
  -lateral 
  borders 
  form 
  a 
  

   sutural 
  union 
  with 
  the 
  pterygoids 
  (see 
  fig. 
  1). 
  On 
  the 
  upper 
  surface 
  

  

  Fig. 
  1. 
  — 
  Posterior 
  portion 
  of 
  palate, 
  showing 
  the 
  relations 
  of 
  the 
  

   parasphenoid 
  and 
  transverse 
  bones. 
  

  

  7n^r—£r 
  

  

  ju. 
  = 
  jugal. 
  

   pal. 
  — 
  palatine. 
  

   pas. 
  = 
  parasphenoid. 
  

  

  pt. 
  = 
  pterygoid. 
  

   sq. 
  = 
  squamosal. 
  

   trs. 
  = 
  transverse 
  bone. 
  

  

  [About 
  I 
  nat. 
  size.] 
  

  

  of 
  the 
  posterior 
  portion 
  of 
  the 
  parasphenoid 
  is 
  a 
  mass 
  of 
  osseous 
  

   tissue 
  of 
  somewhat 
  irregular 
  form. 
  This 
  is 
  probably 
  the 
  remains 
  of 
  

   the 
  anterior 
  portion 
  of 
  the 
  true 
  basis 
  cranii 
  derived 
  from 
  the 
  trabe- 
  

   cule, 
  and 
  either 
  forms 
  an 
  anterior 
  portion 
  of 
  the 
  basisphenoid 
  

   or 
  an 
  imperfectly 
  ossified 
  presphenoid. 
  The 
  length 
  of 
  the 
  exposed 
  

   portion 
  of 
  the 
  parasphenoid 
  is 
  roughly 
  19 
  cm., 
  its 
  width 
  between 
  

   the 
  post-palatine 
  vacuities 
  1'8 
  cm., 
  and 
  its 
  greatest 
  width 
  between 
  

   the 
  pterygoids 
  2-2 
  cm. 
  

  

  The 
  pterygoids 
  (jot.), 
  in 
  their 
  general 
  form 
  and 
  relations, 
  are 
  

   closely 
  similar 
  to 
  those 
  of 
  PeJoneustes, 
  but 
  there 
  are 
  one 
  or 
  two 
  

   well-marked 
  differences. 
  The 
  anterior 
  rami, 
  which 
  are 
  very 
  stout 
  

   and 
  massive, 
  widen 
  gradually 
  from 
  before 
  backward, 
  and 
  unite 
  

   externally 
  with 
  the 
  palatines 
  in 
  a 
  straight 
  suture 
  (convex 
  externally 
  

  

  