Eudendrium racemosum ( Cavolini, 1785 )

Watson, Jeanette E., 2012, Some hydroids (Hydrozoa: Hydroidolina) from Dampier, Western Australia: annotated list with description of two new species., Memoirs of Museum Victoria 69, pp. 355-363 : 355

Eudendrium racemosum ( Cavolini, 1785)

Figure 1A

Sertolaria racemosa Cavolini, 1785: 160 , pl. 6, figs 1–7, 14–15 Sertularia racemosa . – Gmelin, 1791: 3854 Eudendrium racemosum .– Ehrenberg, 1834: 296.– von

Lendenfeld, 1885: 351, 353.– Millard and Bouillon, 1973: 33.– Watson,

1985: 204, figs 63–67

Material examined. WAM Z31857, material ethanol preserved. Four infertile colonies, the tallest 40 mm long, on purple sponge.

Description. Hydrorhiza a tangled mass of stolonal tubes. Stems fascicled, stolons becoming stems in a loose untidy mass of tubes with much adventitious matter embedded between the tubes. Largest colony comprised of several heavily fascicled main branches, branching and rebranching roughly alternate, ultimate branches monosiphonic. Hydranth pedicels more or less alternate on ultimate branches, cylindrical, smooth, length variable, with two to four obscure annulations at base. Hydranth large with approximately 20 stubby tentacles.

Cnidome: all nematocysts undischarged,

– small euryteles, abundant in tentacles,

– large isorhizas, rare on hydranth body.

Figures

Figure 1A–G. A. Eudendrium racemosum from photograph of whole colony. B. Filellum serratum, regenerated hydrotheca. C, D. Lafoeina amirantensis. C, small hydrotheca and nematotheca on hydrorhiza. D, large hydrotheca. E–G. Halecium?tenellum. E, unbranched stem. F, basally annulated hydrophore. G, hydrotheca with strongly everted rim and desmocytes. Scale bar, mm: A, 20. B, C, E, F, G, 0.2. D. 0.1.