Habitat: Mud fields Distribution: Florida Keys, Colombia, and the Bocas del Toro Archipelago. Natural History Notes: Live a life of subterranean suclusion 20-100 mm below the bottom of the ocean, making them difficult to locate. Depth: 12-220 meters Characteristics: Yellowish tan or light-brown medium sized urchin that grows up to 75 mm long. Has a distinctly heart-shaped test that is almost spherical. There are four sunken petals with the anterior pair curved and much longer than the posterior pair. Distinctive dark brown peripetalous fasciole is also present. Tube fee in the anterior groove are bright red.