[3] Members of the genus are characterised by having long arms with pointed tips fringed with spines.

The upper marginal plates are replaced by paxillae, but the lower marginal plates are large and covered with paxillae.

The tube feet do not have suckers, but have two swollen regions.

However, they are capable of larval cloning, with asexual reproduction taking place while they are larvae.

This has been shown to take place both in the field and in laboratory cultures and has been studied by molecular analysis of sequences of mitochondrial tRNA to identify the taxa involved.