Haeckel 1888
Siphonophores with a relatively small apical pneumatophore. A nectosome with an array of identical nectophores is, with two exceptions, present. The number of nectophores is specifically variable, but they are usually arranged biserially, except in the family Forskaliidae. The cormidia, arranged linearly down the stem, are comprised of a gastrozooid and tentacle, and a specifically variable number of bracts and gonodendra, the last not bearing asexual swimming bells. As is always the case there is an exception in that one species does not have bracts. In addition to these cormidial elements palpons with palpacles usually are present, but they are absent in some species. About 50 species presently distributed amongst 7 families, although it is clear that some revision is necessary. Species from all 7 families occur in the South Atlantic, but as those of the family Rhodaliidae are benthic, using their tentacles to tether themselves to the substrate (Pugh, 1983; Hissmann et al., 1995), they will not be considered here. Riemann-Zürneck (1991) gives details of the distribution of Rhodalia miranda Haeckel, 1888. The other 6 families (listed at the bottom of this page) can be distinguished according to the arrangement of the nectosome and siphosome. The diagnoses will mainly concentrate on the distinguishing features of the nectophores or bracts, as these are the parts most frequently found in net samples.
Jump to the key: Page 313: Order Physonectae
Family Apolemiidae
Family Agalmatidae
Family Pyrostephidae
Family Physophoridae
Family Athorybiidae
Family Forskaliidae