THE EVOLUTION OF MAN. 



kingdom as a genuine Worm. The difference between it 

 and other genuine Worms cannot have been, greater than is 



FIG. 187. Appendicmaria, seen from the left side : m, month ; Ic, gill- 

 intestine ; o, oesophagus ; v, stomach ; a, arus ; n, nerve-ganglia (upper 

 throat-knots) ; g, ear-vesicle ; /, ciliated groove under the gill ; h, heart ; 

 t, testes ; e, ovary ; c, notochord ; s, tail. 



FIG. 188. Structure of an Ascidian (seen from the left, as in Fig. 153 

 and Fig. 14, Plate XI.) : sb, gill-sac ; v, stomach ; i, large intestine ; c, 

 heart ; t, testes ; vd, seed-dnct ; o, ovary ; o', matured eggs in the body- 

 cavity. (After Milne Edwards.) 



