The ophiuroids are echinoderms with a well-defined central disk and five
long, slender, whip-like arms. They have been called brittle stars
because of their ability to shed their arms when they are disturbed.
Their long, slender, snake-like arms have also resulted in their being
called serpent stars. Ophiuroids range from Ordovician to Recent in age,
but because of the delicate nature of their bodies they are seldom found
as fossils. Ophiuroid remains have been found in certain Mesozoic and
Cenozoic rocks of Texas, but they consist largely of small segments of
the arms or body fragments.