(Synthecium) (Synthecium) is a biological genus in the family Syntheciidae and order Leptothecatae (Thecate Hydroids).
Synthecium carinatum
Synthecium cylindricum
Synthecium elegans
Synthecium longithecum
Synthecium maginatum
Synthecium patulum
Synthecium robustum
Synthecium symmetricum
Synthecium tottoni
Synthecium tubithecum