In this article we will discuss about the structure of Ophiothrix with the help of a diagram.
1. They are commonly known as brittle stars, are found in shallow waters and are usually of a green colour.
2. Body comprises of a distinct and some what rounded disc and five narrow, flexible, jointed and slender arms radiating from it.
3. Animal has a distinct oral and an aboral surface.
4. The disc, on the aboral surface, bears a large central protuberance (papillae) in the centre surrounded by 5 medium sized radial protuberances, which in turn are surrounded by smaller papillae. There are also present 5 pairs of adradial papillae on the periphery.
5. Oral surface of the disc bears a pentaradiate mouth in the centre which is surrounded by large oral papillae and numerous closely set granules.
6. Arms, on the aboral surface, bear a median row of large radial shields and peripheral rows of small, irregular scales with numerous small inter-sperced spines.
7. Sexes are separate and genital bursae 4 in each inter radius.
8. Ambulacral grooves, pedicillariae branchiae and dermal papillae are absent.
9. The oral surface of each arm bears small tube feets.