PYROSOMA. 



523 



Fig. 150.— Pyro-^oma giganteum.—l. A vertical section of the wall of the Ai=cidiariuin 

 near the cloacal aperture and inclndinii- its lip. II. Tlie younfrest condition of a 

 bud before the ectoderm is elevated. III., IV., V. Further stasres of the develop- 

 ment of a bud. VI. A fully-formed bud with a second ascidiozoOid in course of 

 development from its peduncle. 



