Keyword Album: Ceratosoma gracillimum Most species of Ceratosoma are best identified by their body shape rather than their colour, which is quite variable. In this species, Ceratosoma gracillimum, the mantle edge is reduced to a ledge around the head end of the body and a lobe on each side just in front of the gills. Ceratosoma trilobata is somewhat similar, but in that species the anterior ledge around the head and the lobes are connected by a ridge down each side. Bill Rudman