

A. 



a^'^-^t? ..* -*« rt> ^Vl^^;^V/:■{/:S^y;•■^;C\Vv^^•^;v^ .1*^*'^ ^%** '''j'**'' t'l""*' 





B.: 



SEGMENTATION CAVITY 

 CENTRAL CELLS 



MARGINAL 

 CELL 



SP^^^i 



• ^ '•^ .- \\*,. ■*''>*?: **..:l:^^^0S^■^'.'^siL'i§^0h^»^l•. *' -*" 



., ^•4>!r';^- ,- --s-^■ 



E. 



Fig. 156. (See facing page for legend.) 

 314 



