Uintacrinus ("crinoid from the Uinta Mountains") is an extinct genus of crinoids from the Cretaceous of Kansas. It was unusual among crinoids because it had no stalk, and probably floated above the seafloor.Mike Everhart, (2004). https://www.oceansofkansas.com/Uintacrinus.html It lived in the Western Interior Seaway. This crinoid was a colonial animal with ten long arms each that it used to capture prey.Mike Everhart, (2004). https://www.oceansofkansas.com/Uintacrinus.html
Footnotes
Sources Fossils (Smithsonian Handbooks) by David Ward (Page 174) "Notes on Uintacrinus socialis Grinnell" https://www.oceansofkansas.com/Uintacrinus.html
References Everhart, Mike "Notes on Uintacrinus socialis Grinnell" https://www.oceansofkansas.com/Uintacrinus.html