Crinoids - Fifeocrinus Arms a.jpg
Fifeocrinus Crinoid Arms
SITE LOCATION: Chesterian Zone of the Bangor Limestone Formation in northern Alabama
TIME PERIOD: Mississippian Period (ca 325,000,000 yrs old)
Data: Crinoids are marine animals that make up the class Crinoidea of the echinoderms (phylum Echinodermata). The name comes from the Greek word krinon, "a lily", and eidos, "form". Crinoids are characterised by a mouth on the top surface that is surrounded by feeding arms. They have a U-shaped gut, and their anus is located next to the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, most crinoids have many more than five arms. Crinoids usually have a stem used to attach themselves to a substrate, but many live attached only as juveniles and become free-swimming as adults.