KEY PLATE 20. 



FIG 



; ' v lDr V ' VA %D $&f^* SKr* 







L*T*rS?C , w..-i-s..vT-T k . ( * jf .1. J 



k. rZJkr! t? 1 **- / W .v^. VT**. * * jy , 



feivwti-'asjs* i^ ^.^.v^^- /<yr < 

 ^^|^m^Mp> 



^>'P^T^:^'^y 



Fl G. 2 



