Nematostella

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Phylum: Cnidaria
Classis: Anthozoa
Subclassis: Hexacorallia
Ordo: Actiniaria
Subordo: Nyantheae
Infraordo: Athenaria
Familia: Edwardsiidae
Genus: Nematostella 

Characteristics

Edwardsiidae with the column divisible into physa, scapus, scapulus and capitulum, though these regions may be slightly distinguished. Scapus with or without adherent material, without nemathybomes and tenaculi. Tentacles 10-18, the outer longer than the inner. A single, ventral siphonoglyph. Mesenteries as in Edwardsia. Retractors in comparison with those of other Edwardsiidae rather weak. Ciliated tracts may be discontinuous. Curious, ciliated, spherical bodies, nematosomes, containing nematocysts occur in the coelenteron, in which they swim about. Cnidom: spirocysts, basitrichs, microbasic p-mastigophors.

References

* Carlgren, O. 1949. A Survey of the Ptychodactiaria, Corallimorpharia and Actiniaria. Kungl. Svenska Vetenskapsakadamiens Handlingar, series 4, volume 1, number 1.
* 2010: Zootaxa, 2343: 66–68.