Halecium ovatum Totton, 1930

Watson, Jeanette E., 2008, Hydroids of the BANZARE expeditions, 1929 – 1931: the family Haleciidae (Hydrozoa, Leptothecata) from the Australian Antarctic Territory, Memoirs of Museum Victoria 65, pp. 165-178 : 172

Halecium ovatum Totton, 1930

Figure 8A, B

Halecium ovatum Totton, 1930: 143 , fig. 3.- Vervoort, 1972: 339, fig. 1.- Stepanjants, 1979: 103, pl. 20 fig. 1a-g.- Peña Cantero, 1991: 48, pl. 2, figs g-h.- Blanco, 1994: 160: 156.- Blanco, 1994: 187.- Peña Cantero and García Carrascosa, 1996: 12, fig. 2G-H.- Peña Cantero and García Carrasocosa, 1999: 63: 212 et seq.- Watson, 2003: 166 , fig. 15 D,E.- Vervoort and Watson, 2003: 86.

Notes and supplementary description from holotype. To establish the identity of Halecium interpolatum it became necessary to examine type material of Halecium ovatum . Although Totton provided an adequate description and dimensions of Halecium ovatum his figures were poor, and the gonotheca was not figured. Ihave compared the BANZARE material with the holotype (alcohol-preserved colony) and four paratype microslide preparations of Halecium ovatum loaned bythe Natural History Museum, London.Abrief supplementary description of the important diagnostic characters from the holotype (glycerol-mounted) of Halecium ovatum is given.

The holotype colony ( BMNH No.29.10.10.1) comprises a dense tuft of long and short stems growing on another hydroid. Hydrocauli arise from a tangled adherent meshwork of tubular stolons entwined with hydrorhizae of the other hydroid .

Shorter stems monosiphonic, taller stems fascicled with up to 10 polysiphonic tubes; stems arborescently branched in all directions up to two thirds of their length, ultimate branches monosiphonic.

Mature female gonothecae small, borne abundantly on all but distalmost branches, inserted on a short pedicel in a hydrotheca typically situated in a fork between two or three branches but hydrotheca often overgrown by polysiphonic tubes; body of gonotheca ovoid to subquadrangular with a very thin, smooth perisarc; aperture terminal, small, circular, surrounded by a very low fragile collar; immature gonotheca kidney-shaped as described by Totton.

Nematocysts in tentacles undischarged?anisorhizas capsule oval, 11–12 x 6–7 μm.

Measurements (μm) of gonotheca of Halecium ovatum

Length of pedicel of gonotheca 80 Length of gonotheca 784 – 1176 Width of gonotheca 588 – 901 Diameter of orifice 80

Figures

Figure 8. A, B. Halecium ovatum, holotype colony, BMNH Reg. No. 29.10.10.1. A, part of stem.B, empty female ovoid and subquadrangular gonothecae. Scale bar: A, 10 mm. B, 1 mm.