Describe a starfish in terms of symmetry, germ cell layers, coelem, Circulatory system, reproduction, feeding, excretion and nervous system. Find picture examples of each living class Crinoidea, Ophiocistioidea, Astroidea, Echinoiudea and Holothuidea.

The starfish has 5 rays or arms, most of the space in the ray is covered up by the starfishes branched digestive glands. The food that goes through the starfish's is partially digested through the anus of the starfish. The anus of a starfish is where the waste products are released to the outside. There are two rectal pouches near the anus, which functions as a temporary storage for the waste products before being released. the male and female gonads look very alike to the point where it has to be microscopically examined to tell the difference. The ovaries of a starfish are considered to be larger than the sperm, and the testes have flagellated sperm. The water vascular system consists of seawater filled ducts that help the starfish feed and move around.

Crinoidea

Ophiocistioidea

Astroidea

Echinoiudea

Holothuidea

Sources: The little booklet from Starfish Dissection and google images.