Domain Eucaryota Subdomain Amoebota Doweld (2001) Kingdom Hydrobiota Doweld, 2001 Subkingdom Hydrobiotina Doweld, 2001 [monotypic] Phylum Hydrozoa Owen, 1843 Class Stenoscyphatea Doweld, 2001 [monotypic] Order Stenoscyphida Doweld, 2001 [monotypic] 1 Family Stenoscyphidae Kishinouye, 1902