Geology Page's video: Arthroacantha carpenteri Crinoid Fossil

Crinoid | Crinoids are marine animals belonging to the Crinoidea class, one of the phylum Echinodermata classes, which also includes starfish, brittle stars, sea urchins and sea cucumbers. Those crinoids which, in their adult form, are attached to the bottom of the sea by a stalk are commonly referred to as sea lilies, whereas the unstalked forms are referred to as feather stars or comatulids. Adult crinoids are characterized by the bottom layer of the mouth. This is encircled by holding weapons and is connected to a U-shaped intestine with the anus situated close the mouth on the oral sac. There are only about 600 species of crinoid residing there. But in the past, the school was a lot more abundant and varied. Some dense calcareous deposits from the mid- to late-Paleozoic period consist almost completely of disarticulated crinoid pieces. Location: Hamilton group , Ontario Canada. Devonian era 380 million years old. Video Copyright ©Tony Petropoulos www.geologypage.com