9O THE EVOLUTION OF MAN. 



kingdom as a genuine Worm. The difference between it 

 and other genuine Worms cannot have been greater than is 



Fio. 187. Appendicalaria, seen from the left side: m, mouth; ^gill- 

 intestine ; o, oesophagus ; v, stomach ; a, anus ; n, nerve-ganglia (uppei 

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

 t, teetes ; e, ovary ; c, notochord ; a, tail. 



FIQ. 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 duct ; o, ovary; o', matured eggs in the bod"y 

 cavity. (After Milue Edwards,) 



