CBSE Class 9 Answered

Members of Phylum Echinodermata have following features:

i. They are triploblastic, coelomates, unsegmented and show pentamerous symmetry in adults.

ii. Their body is without head, but have oral and aboral surfaces.

iii. They are characterized by the presence of water-vascular system that extends from the body surface as a series of tentacle-like projections. 

iv. Digestive system is usually complete, but excretory organs are absent.

v. Sexes are separate and fertilization is usually external.