﻿52 
  PROCEEDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIETY. 
  

  

  on 
  tlie 
  poriphero-lateral 
  area, 
  and 
  a 
  broad 
  shallow 
  hyponomic 
  sinus 
  

   on 
  tlie 
  peripliery. 
  Tiiese 
  growth-lines 
  probably 
  constituted 
  the 
  only 
  

   ornaments 
  of 
  the 
  test. 
  

  

  The 
  mesh 
  work 
  surface 
  passing 
  into 
  the 
  fine 
  irregular 
  striae 
  on 
  the 
  

   peripb.eral 
  area 
  and 
  into 
  the 
  finely-cancellated 
  structure 
  on 
  the 
  lateral 
  

   area 
  doubtless 
  represents 
  the 
  so-called 
  ' 
  llunzelschicht 
  ' 
  or 
  ' 
  wrinkle- 
  

   layer 
  ', 
  which 
  has 
  been 
  reco;i;nized 
  and 
  described 
  in 
  quite 
  a 
  number 
  of 
  

   amraonoids, 
  and 
  which 
  is 
  comparable 
  with 
  the 
  structure 
  in 
  the 
  recent 
  

   Nautilus 
  known 
  as 
  the 
  ' 
  black-layer', 
  which 
  is 
  seen 
  on 
  the 
  peripheral 
  

   surface 
  of 
  the 
  early 
  part 
  of 
  the 
  last 
  whorl 
  and 
  immediately 
  in 
  front 
  of 
  

   the 
  aperture. 
  

  

  