IDENTIFICATION (with reason) OF Echinus sp. (B.Sc. ZOOLOGY_CCF-CC5_SEM4)

    Identifying features are:

1. Multicellular heterotroph.
2. embryonic development, preceded by heterogametic fertilization.

            Hence, the specimen belongs to the Kingdom Animalia.

1. Usually exhibit pentamerous symmetry.
2. Presence of external spines.
3. Oral surface directed downward.
4. Tube foot is present.
5. Five grooves named ambulacra are usually present.

           Hence, the specimen belongs to the Phylum Echinodermata

1. Globoid or discoid body without arms or brachioles.
2. Madreporite & anus remain on the aboral side.
3. Mouth is present on the aboral side. Directed downwards or forwards.
4. Ambulacral grooves are covered.

             Hence, the specimen belongs to the Sub Phylum Echinozoa.

1. Spherical, discoidal or heart shaped body.
2. Madreporite & anus remain on the aboral side.
3. Ambulacral grooves are meridional in position.

             Hence, the specimen belongs to the Class Echinoidea

1. Ossicles fused to form an internal test on which movable spines are mounted.
2. Spines may be hollow or solid.
3. Three jawed pedicellariae and sphaeridia are present among the spines.
4. Anus at the centre of upper surface is surrounded by periproct.
5. Presence of Aristotle's lantern.

            Hence, the specimen seems to be Echinus sp.

Systematic Position (Ruppert & Barnes 1994)

 Kingdom: Animalia

   Phylum: Echinodermata

         Sub Phylum: Echinozoa

                 Class: Echinoidea

                     Genus: Echinus