“Individuals were observed in situ at depths of 9-15 m off Fort Pierce, Florida, in coarse, ripple-marked sediment. Other echinoderms in this habitat include the sand dollar
Encope aberrans and burrowing amphiurid brittle stars. Their feeding tentacles are sometimes extended into the water column; however, most individuals remain hidden beneath the ripple crests. When disturbed, they quickly withdraw their tentacles and introvert, as deep as 10 cm below the sediment surface. When tightly grasped and roughly pulled from the sediment by hand, their bodies are quite long (more than 30 cm) and contorted. Within 10-15 seconds after removal from the sediment, they contract into a uniform U-shape, less than 10 cm in length, and resemble individuals gently excavated from below. Evidently, "ballooning" the body is a defensive mechanism that serves to obstruct removal from the sediment (Miller and Hendler, previously unpublished). Specimens have most commonly been collected by dredge, a process that results in a characteristic pattern of damage. The dredged individuals separate (autotomize) into two pieces, the main body from just behind the introvert to the anus and a much shorter piece consisting of the introvert, tentacles, calcareous ring, and associated structures” (Hendler, Miller, Pawson, Kier 274)