Some hydroids (Hydrozoa: Hydroidolina) from Dampier, Western Australia: annotated list with description of two new species. Author Watson, Jeanette E. text Memoirs of Museum Victoria 2012 2012-12-31 69 355 363 https://museumsvictoria.com.au/collections-research/journals/memoirs-of-museum-victoria/volume-69-2012/pages-355-363/ journal article 10.24199/j.mmv.2012.69.09 1447-2554 12212553 Halecium tenellum Hincks, (1861) Figure 1E– G Halecium tenellum Hincks, 1861a: 252 , pl. 6, figs 1–4.– Vervoort, 1959: 229 , fig. 8.– Vervoort, 1966: 102 , fig. 2.– Millard, 1975: 156 , fig. 50F–L.– Vervoort and Watson, 2003: 98 , fig. 19A, B. Material examined. WAM Z31849. Abundant infertile colonies on Eudendrium racemosum ; one microslide, malinol mount. Description. Hydrorhiza creeping on host, stolons tubular, undulating. Hydrocaulus monosiphonic, cylindrical, variable in length, mostly unbranched but some branched once or twice. Hydrophore smooth, cylindrical, a few transverse proximal septa marking site of branching from below or within a hydrotheca; hydrophore expanding slightly to below hydrotheca. Hydrotheca shallow dish–shaped, expanding to margin, rim strongly outrolled, diaphragm transverse, a row of desmocytes above, no marginal replications. Perisarc smooth, thin.