Larval nectophore whose nectosac occupies the basal half and has 4 straight radial canals. The long, narrow hydroecium bends over one side of the nectosac. The narrow, curved somatocyst may have a slight terminal swelling. Small hemispherical bract, with minute neck shield and shallow hydroecium. The long, club-shaped phyllocyst is obliquely angled.
Kingdom Animalia Phylum Cnidaria Class Hydrozoa Subclass Siphonophorae Order Calycophorae Family Sphaeronectidae Genus Sphaeronectes Species Sphaeronectes gracilis