Large rhomboidal definitive nectophore bearing a faint pattern of surface ridges. Small nectosac offset laterally; obliquely slanted, deep hydroecium with narrow opening. Complexly divided somatocyst. Large, roughly triangular bract with a vague ridge pattern and a small hydroecium. Phyllocyst complexly divided.
Kingdom Animalia Phylum Cnidaria Class Hydrozoa Subclass Siphonophorae Order Calycophorae Family Prayidae Subfamily Nectopyramidinae Genus Nectadamas Species Nectadamas diomedeae