﻿Varanosauiui? 
  acutirostris, 
  Broili. 
  309 
  

  

  14. 
  The 
  considerable 
  resemblance 
  between 
  the 
  humeri 
  of 
  

  

  the 
  two 
  types. 
  

  

  15. 
  The 
  sudden 
  thickening 
  of 
  the 
  symphysis 
  between 
  the 
  

  

  pubes. 
  

  

  16. 
  The 
  femora 
  present 
  many 
  curious 
  resemblances. 
  

  

  The 
  types 
  differ 
  in 
  the 
  following 
  features 
  : 
  — 
  

  

  1. 
  The 
  snpraoccipital 
  of 
  Labidosaurus 
  is 
  narrow 
  and 
  quite 
  

  

  unlike 
  that 
  of 
  Varanosaurus. 
  

  

  2. 
  The 
  post-temporal 
  fossae 
  are 
  not 
  small 
  and 
  widely 
  

  

  separated 
  in 
  the 
  Captorhinid?e. 
  

  

  3. 
  The 
  angular 
  is 
  not 
  flat 
  and 
  the 
  lower 
  jaw 
  not 
  in 
  the 
  

  

  least 
  Tlierapsid 
  in 
  Labidosaurus. 
  

  

  It 
  will 
  be 
  noticed 
  that 
  those 
  features 
  in 
  which 
  the 
  two 
  

   types 
  differ 
  are 
  characteristic 
  of 
  the 
  Therapsid 
  group 
  as 
  a 
  

   whole. 
  

  

  Of 
  the 
  other 
  typical 
  Therapsid 
  characters, 
  the 
  most 
  im- 
  

   portant 
  are 
  the 
  high 
  brain-cavity 
  and 
  the 
  low 
  position 
  of 
  the 
  

   ear, 
  of 
  which 
  the 
  material 
  at 
  my 
  disposal 
  did 
  not 
  give 
  quite 
  

   satisfactory 
  information, 
  but 
  suggests 
  that 
  in 
  these 
  features 
  

   Labidosaurus 
  agrees 
  with 
  the 
  Therapsid 
  type. 
  

  

  This 
  series 
  of 
  resemblances 
  and 
  differences 
  are 
  exactly 
  

   what 
  one 
  would 
  expect 
  if 
  the 
  Captorhinidae 
  are 
  the 
  compara- 
  

   tively 
  little 
  modified 
  descendants 
  of 
  the 
  group 
  of 
  Cotylosaurs 
  

   from 
  which 
  the 
  Therapsid 
  phylum 
  sprung 
  ; 
  in 
  curious 
  

   characters, 
  mostly 
  of 
  trivial 
  morphological 
  importance, 
  

   Varanosaurus 
  resembles 
  them 
  exactly. 
  In 
  the 
  important 
  

   features 
  which 
  proclaim 
  it 
  a 
  typical 
  member 
  of 
  the 
  Therapsid 
  

   stock, 
  it 
  differs 
  entirely 
  from 
  them, 
  with 
  probably 
  one 
  very 
  

   important 
  exception 
  — 
  that 
  the 
  brain-cavity 
  of 
  both 
  types 
  is 
  

   similar, 
  and 
  different 
  from 
  that 
  of 
  other 
  Cotylosaurs 
  and 
  

   other 
  reptiles. 
  If 
  this 
  is 
  so, 
  and 
  it 
  will 
  be 
  remembered 
  that 
  

   the 
  evidence 
  is 
  very 
  unsatisfactory, 
  we 
  have 
  again 
  a 
  fine 
  

   illustration 
  of 
  the 
  fact 
  that 
  the 
  leading 
  part 
  of 
  evolution 
  

   takes 
  place 
  in 
  the 
  brain, 
  changes 
  in 
  which 
  long 
  precede 
  those 
  

   of 
  other 
  parts 
  of 
  the 
  organism. 
  

  

  One 
  interesting 
  point 
  on 
  which 
  light 
  is 
  shed 
  by 
  Varano- 
  

   saurus 
  is 
  the 
  identification 
  of 
  the 
  temporal 
  bones. 
  

  

  There 
  is 
  not 
  the 
  faintest 
  doubt 
  that 
  the 
  bone 
  1 
  have 
  called 
  

   squamosal 
  is 
  the 
  same 
  as 
  the 
  mammalian 
  bone 
  of 
  that 
  nanie. 
  

   In 
  all 
  its 
  relations 
  and 
  appearances 
  it 
  agrees 
  with 
  that 
  of 
  the 
  

   Deinocephalia, 
  from 
  which 
  we 
  have 
  a 
  continuous 
  series, 
  with 
  

  

  Ann. 
  ik 
  Mag. 
  N. 
  Hist. 
  Ser. 
  8. 
  Vol. 
  xiii. 
  21 
  

  

  