The Phylum Sipuncula

Etymology: From the Greek Acantha a prickle, and Kephale a head.

Characteristics of Sipuncula:

1. Bilaterally symmetrical and vermiform.
2. Body has more than two cell layers, tissues and organs.
3. Body cavity is a true coelom.
4. Body possesses a U shaped gut with a mouth and anus.
5. Body covered in a rubbery cuticle.
6. Has a simple brain and a ventral main nerve.
7. Has no circulatory or respiratory organs.
8. Reproduction normally sexual and gonochoristic, some species can be asexual and one species is parthenogentic.
9. Feed on algae, diatoms, protista etc., one species is a parasite.
10. All live in marine environments.