- :!.■ II >,(■---,- 







l"in 18 Diagraiu sliowhig the piftnriiig of iicvspective by animals 

 patterns. The bird is supposed to be % pitically placed, and hwked some- 

 what lUwii upon against a uniformly patterned horizontal ground-plane. 



Fig. 19. Diagram supplenieutiiig Fig. 18, showing the 

 coarser Sacft-pa'tteni, required to match the ground- 

 pattern un-fore.5hortened and almost undiminished, as 



patte-- -- 



when seen from directly above. 



Fig. 21. Shows particularly well the head-markings 

 picturing of a shadowed cavity crossed by lighted twig 

 or grasses. 



Figs. 20-21. American Woodcock on its nest; showing the working of the wonderful obliterative picture-patterns, founded on counter- 

 shading. 



