( 467 ) 

 TABLE XI. 



Systematic Survey showing the derivation of the germ-layers of the Amphioxns 

 from the parent-cell (cytula), and of the main organs from the germ-layera. 



(Tree showing the ontogenetic descent of the cells in the Amphicxas).'** 



{T.ainina neurodermalis) (^T/imina inodermalis) {Lamina inogasti-alis) (^Laminamyxogaslralit) 

 (Fig. 157, hs) (Fig. 157, hf) (Fig. 157, dj ) (Fig. 157, dd) 



Exoderma (Fig. i55, e) 

 (Skin-layer, or outer germ-layer) 



>v_ 



Entoderma (Fig. 155, i) 

 (Intestinal layer, or inner germ-layer) 



Gastrula fFi- 22, j, k "i 

 (Cup-germ) LFig. 155, p. 444 J 



Blastula (Fig. 22, F, G) 

 (Dladder-germ) 



Morula (Fig. 22, E) 

 (Mull)erry-germ) 



Cytula (Fig. 22, B) 

 (Parent-cell) 



22 



Monerula (Fig. 22, J) 

 (Parent-cytod) 



