sentences:  Some tropical sea urchins like Diadematidae, Echinothuriidae and Toxopneustidae have venomous spines.Other creatures also make use of these defences; crabs, shrimps and other organisms shelter among the spines, and often adopt the colouring of their host.Some crabs in the Dorippidae family carry sea urchins, starfish, sharp shells or other protective objects in their claws.