On a collection of hydroids (Cnidaria, Hydrozoa) from the southwest coast of Florida, USA Author Calder, Dale R. text Zootaxa 2019 2019-10-25 4689 1 1 141 journal article 25128 10.11646/zootaxa.4689.1.1 a63613b4-e611-42e8-89cd-2d3aae126759 1175-5326 3519047 41BFBBDF-41AD-4329-B6B9-CF38D64815A6 Halecium sp. Figs. 19e, f Material examined. Southwest Florida Shelf, middle shelf west of Gasparilla Island, 26°45.86’N , 83°21.44’W , 50 m , 18 July 1981 , triangle dredge, one colony fragment, 3.9 cm high, without gonophores, coll. Continental Shelf Associates, ROMIZ B1594.— Sanibel Island , beach at Lighthouse Point , 26°26’58”N , 82°01’04.5”W , detached and stranded on beach, 21 March 2018 , 22° C, 34.5‰, one colony, 7 cm high, with male gonophores, coll. D. Calder , ROMIZ B4381 . Remarks. These hydroids resemble the trophosomes of several species of Halecium Oken, 1815 that have been reported from the Gulf of Mexico ( Calder & Cairns 2009 ), including H. halecinum ( Linnaeus, 1758 ) , H. beanii ( Johnston, 1838 ) , H. sessile Norman, 1867 , H. macrocephalum Allman, 1877 , and H. bermudense Congdon, 1907 . In lacking female gonophores, the specimens cannot be reliably identified to species. Colonies were strongly polysiphonic, with alternate and predominantly pinnate side branches; hydranths bore 20+ tentacles and the cnidome comprised both pseudostenoteles (10.2–12.0 long x 5.4 7.0 μm wide) and microbasic mastigophores (ca. 6.0 long x 1.8 μm wide).