Hydrozoa note details
Colonies stolonal or erect, arising from creeping hydrorhiza; hydrocauli monosiphonic or polysiphonic; hydrothecae shallow to bell-shaped, sessile or pedicellate, basal region with delicate diaphragm, with or without desmocytes; hydranths usually much larger than hydrothecae, with or without an intertentacular web. Nematophores present, with variably reduced nematothecae. Gonophores fixed sporosacs; gonothecae solitary or aggregated to form a glomulus
Choong H., Calder D., Chapman J., Miller J., Geller J., Carlton J. (2018). Hydroids (Cnidaria: Hydrozoa: Leptothecata and Limnomedusae) on 2011 Japanese tsunami marine debris landing in North America and Hawai‘i, with revisory notes on Hydrodendron Hincks, 1874 and a diagnosis of Plumaleciidae, new family. Aquatic Invasions. 13(1): 43-70.