Comprehensive DescriptionRead full entry
DescriptionA colonial hydroid forming a series of short shoots arising from a rather straight stolon that grows parallel to the edge of Zostera marina leaves. Erect shoots rigidly zigzag, to about 15 mm. The hydrothecae, a supporting, nonliving, protein-chitinous envelope surrounding the stem, is thin-walled with an even rim.Apparently confined to the seagrass Zostera marina in southern England where it can withstand salinity at least as low as 17.7 psu (Cornelius, 1995b). Cornelius (1995b) notes that there have been few British records since the decimation of British eel-grass during the 1930's. The records from Belfast Lough and the Isle of Man are from the 19th century. Most records on the distribution map are from MNCR and BioMar surveys (JNCC, 1999). However, records from the Menai Strait and from Clovelly have not been included and are considered dubious. A record from Skomer (Crothers, 1966) is considered dubious by Cornelius (1995b).