﻿Smithsonian 
  Report. 
  1943. 
  -Friedmann 
  

  

  B 
  

  

  X 
  

  

  ^ 
  ' 
  I 
  I 
  

  

  1. 
  Constructive 
  Shading. 
  

  

  A. 
  extreme 
  dark 
  and 
  light 
  tones 
  connected 
  by 
  intermediate 
  shading, 
  giving 
  a 
  smoothly 
  rounded 
  appearance; 
  

   B, 
  extreme 
  dark 
  and 
  light 
  tones 
  in 
  contrasting 
  juxtaposition, 
  giving 
  the 
  effect 
  of 
  ridges; 
  C, 
  a 
  leaf 
  caterpillar 
  

   (EpistoT 
  gorgon) 
  with 
  constructive 
  shading 
  giving 
  the 
  appearance 
  of 
  leaf 
  vein 
  ridges. 
  (Drawn 
  by 
  W. 
  A. 
  

   Weber, 
  after 
  H. 
  B. 
  Cott.) 
  

  

  

  2. 
  Shadow 
  Elimination 
  in 
  the 
  Horned 
  Toad 
  (Phrynosoma 
  cornutum). 
  

  

  A, 
  the 
  animal 
  as 
  it 
  appears; 
  B, 
  a 
  diagrammatic 
  cross 
  section 
  to 
  show 
  the 
  lateral 
  flanges 
  covering 
  the 
  shadow; 
  

   C, 
  a 
  diagrammatic 
  cross 
  section 
  of 
  what 
  the 
  animal 
  would 
  look 
  like 
  if 
  it 
  did 
  not 
  have 
  the 
  lateral 
  flanges; 
  

   note 
  the 
  revealing 
  shadow. 
  (Drawn 
  by 
  W. 
  A. 
  Weber.) 
  

  

  