GENERAL HISTOLOGY

Detailed explanation-1: -The echinoderms have a radially arranged, pentamerous body structure that is very different from the bilateral body structure of the related deuterostome phyla, the hemichordates and the chordates.

Detailed explanation-2: -Animals in the phylum Echinodermata (such as sea stars, sand dollars, and sea urchins) display radial symmetry as adults, but their larval stages exhibit bilateral symmetry. This is termed secondary radial symmetry.

Detailed explanation-3: -Echinoderms are a phylum exclusively consisting of marine animals. The adults are recognizable by their radial symmetry whereas their larvae are bilaterally symmetrical.

Detailed explanation-4: -Although they may appear very different, echinoderms all have two major defining characteristics that set them apart from all other animals: a water vascular system and five-sided radial symmetry. The water vascular system is a complex series of canals running through an echinoderm’s body (Fig. 3.84).

Detailed explanation-5: -Final answer: Body symmetry in Echinodermata is radial.