﻿150 
  Mr. 
  R. 
  Lydekker 
  on 
  Nototherium 
  and 
  Zygomaturus. 
  

  

  skull 
  figured 
  by 
  Sir 
  R. 
  Owen 
  in 
  pis. 
  xxxvi.-xxxviii. 
  of 
  his 
  

   ' 
  Extinct 
  Mammals 
  of 
  Australia 
  ' 
  as 
  Nototherium 
  Mitchelli 
  

   does 
  not 
  belong 
  to 
  that 
  genus 
  at 
  all. 
  A 
  cast 
  of 
  this 
  skull, 
  

   which 
  I 
  am 
  informed 
  by 
  Mr. 
  W. 
  Davies 
  has 
  been 
  somewhat 
  

   restored, 
  is 
  preserved 
  in 
  the 
  British 
  Museum 
  (no. 
  33259), 
  and 
  

   is 
  entered 
  on 
  p. 
  162 
  of 
  the 
  ' 
  Catalogue' 
  already 
  cited. 
  

  

  This 
  skull 
  is 
  the 
  one 
  to 
  which 
  Mr. 
  Macleay 
  applied 
  the 
  

   name 
  Zygomaturus 
  trilobus. 
  Now, 
  so 
  far 
  as 
  I 
  know, 
  the 
  only 
  

   original 
  publication 
  of 
  that 
  name 
  was 
  in 
  a 
  Sydney 
  newspaper 
  

   of 
  1857 
  *, 
  and 
  since 
  such 
  publication 
  cannot 
  be 
  regarded 
  as 
  

   one 
  entitled 
  to 
  authenticate 
  the 
  name, 
  I 
  have 
  not 
  even 
  quoted 
  

   Zygomaturus 
  as 
  a 
  synonym 
  of 
  Nototherium 
  in 
  the 
  Museum 
  

   ' 
  Catalogue.' 
  

  

  Now 
  Mr. 
  De 
  Vis 
  states 
  that 
  in 
  this 
  skull 
  the 
  upper 
  pre- 
  

   molar 
  is 
  not 
  of 
  the 
  triangular 
  type 
  which 
  obtains 
  in 
  specimens 
  

   which 
  he 
  regards 
  as 
  typical 
  examples 
  of 
  Nototherium 
  ; 
  and 
  

   he 
  figures 
  an 
  isolated 
  upper 
  tooth 
  which 
  he 
  considers 
  to 
  cor- 
  

   respond 
  with 
  the 
  premolar 
  in 
  question, 
  with 
  the 
  conclusion 
  

   that 
  both 
  this 
  specimen 
  and 
  the 
  skull 
  should 
  be 
  considered 
  as 
  

   indicating 
  an 
  animal 
  generically 
  distinct 
  from 
  Nototherium, 
  

   for 
  which 
  he 
  proposes 
  to 
  adopt 
  the 
  name 
  Zygomaturus. 
  

  

  Unfortunately 
  for 
  this 
  contention 
  if 
  the 
  cast 
  of 
  the 
  skull 
  

   no. 
  33259 
  be 
  carefully 
  examined, 
  it 
  will 
  be 
  found 
  that 
  while 
  

   on 
  the 
  right 
  side 
  the 
  tooth 
  in 
  the 
  position 
  of 
  the 
  premolar 
  is 
  

   of 
  the 
  general 
  type 
  of 
  the 
  one 
  figured 
  by 
  Mr. 
  De 
  Vis, 
  on 
  the 
  

   left 
  side 
  the 
  premolar 
  is 
  much 
  smaller, 
  this 
  being 
  clearly 
  

   shown 
  in 
  the 
  reversed 
  figure 
  given 
  by 
  Sir 
  R. 
  Owen 
  in 
  the 
  

   Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xv. 
  pi. 
  vii. 
  tig. 
  1. 
  The 
  differ- 
  

   ence 
  is 
  so 
  great 
  that 
  whereas 
  on 
  the 
  right 
  the 
  so-called 
  pre- 
  

   molar 
  is 
  as 
  long 
  as 
  the 
  first 
  molar, 
  on 
  the 
  left 
  side 
  the 
  

   premolar 
  is 
  much 
  shorter 
  than 
  the 
  molar 
  and 
  is 
  of 
  the 
  trian- 
  

   gular 
  type 
  which 
  Mr. 
  De 
  Vis 
  regards 
  (and 
  rightly) 
  as 
  typical 
  

   of 
  Nototherium. 
  

  

  This, 
  therefore, 
  at 
  once 
  disposes 
  of 
  the 
  contention 
  that 
  

   no. 
  33259 
  cannot 
  be 
  referred 
  to 
  Nototherium. 
  Other 
  evidence 
  

   is, 
  moreover, 
  afforded 
  by 
  the 
  associated 
  specimens 
  nos. 
  43087, 
  

   43087 
  a 
  in 
  the 
  British 
  Museum 
  ('Catalogue,' 
  pp. 
  162-163). 
  

   Thus 
  the 
  former 
  exhibits 
  the 
  base 
  of 
  a 
  triangular 
  premolar 
  of 
  the 
  

   moderately 
  large 
  size 
  of 
  the 
  corresponding 
  tooth 
  of 
  the 
  left 
  side 
  

   of 
  33259, 
  while 
  the 
  latter 
  shows 
  the 
  peculiar 
  form 
  of 
  the 
  zygo- 
  

   matic 
  arches 
  and 
  nasals 
  characteristic 
  of 
  that 
  skull. 
  No. 
  43087 
  

   is 
  most 
  undoubtedly 
  a 
  typical 
  Nototherium, 
  and 
  was 
  referred 
  by 
  

   Sir 
  R. 
  Owen 
  to 
  his 
  N. 
  inerme 
  ; 
  and 
  the 
  characters 
  of 
  the 
  asso- 
  

   ciated 
  nasals 
  and 
  zygomata 
  decisively 
  refute 
  the 
  statement 
  of 
  

  

  * 
  See 
  Owen, 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xv. 
  p. 
  168 
  (1858). 
  

  

  