The taxonomy of 16 species, eight genera, and four families of hydroids referable to the superfamily Plumularioidea McCrady, 1859, from Bermuda is here reviewed and revised. The study was limited to species collected over a depth range from the intertidal zone to 100 m. Diagnoses are provided of all the genera and family-group taxa represented, and each of the 16 species is described and illustrated. Taxa recognized as new include Gymnangiinae, subf. nov., and Cladocarpini, tribe nov. Cladacanthella is proposed as a replacement name for Acanthella Allman, 1883, an invalid junior homonym of Acanthella Schmidt, 1862. Type species are designated for seven nominal genera: Lowenia Meneghini, 1843, Pachyrhynchia Kirchenpauer, 1872, Isocola Kirchenpauer, 1876, Anisocola Kirchenpauer, 1876, Apostasis von Lendenfeld, 1885b, Haptotheca von Lendenfeld, 1885b, and Polysiphonia von Lendenfeld, 1885b (not Polysiphonia Hertwig, 1882). A lectotype is designated of Gymnangium variabilis (Nutting, 1900). Under the First Reviser Principle (ICZN, 1985, Art. 24), precedence is assigned to the name Aglaophenia latecarinata Allman, 1877, over A. perpusilla Allman, 1877, and to Macrorhynchia savignyana Kirchenpauer, 1872, over M. pennaria Kirchenpauer, 1872. Nuditheca, Astrolabia, Pentatheca, and Anarthroclada are transferred from the family Aglaopheniidae Marktanner-Turneretscher, 1890, to the Halopterididae Millard, 1962, based on the morphology of their nematothecae and gonothecae, and the presence, in some cases obscured, of cauline hydrothecae. Descriptors: VENTROMMA HALECIOIDES; MONOTHECA MARGARETTA; PLUMULARIA FLORIDANA; PLUMULARIA SETACEA; PLUMULARIA STRICTOCARPA; ANTENNELLA QUADRIAURITA; ANTENNELLA SECUNDARIA; HALOPTERIS CARINATA; HALOPTERIS DIAPHANA; GYMNANGIUM SINUOSUM; GYMNANGIUM SPECIOSUM; AGLAOPHENIA DUBIA; AGLAOPHENIA LATECARINATA; AGLAOPHENIA RHYNCHOCARPA; MACRORHYNCHIA ALLMANI; MACRORHYNCHIA PHILIPPINA figs 1-21.
Zoogeography, Biogeography (generalities), Geographic distribution