Synthecium subventricosum Bale, 1914

Watson, Jeanette E., 2018, Some Hydroids (Cnidaria, Hydrozoa) from the Great Australian Bight in the collection of the South Australian Museum, Zootaxa 4410 (1), pp. 1-34 : 16

Synthecium subventricosum Bale, 1914

Figure 7C

Synthecium subventricosum Bale, 1914a: 5 , pl. 1, figs 3–5.— Bale, 1915: 265.— Jarvis, 1922: 345.— Stranks, 1993: 19.— Vervoort & Watson, 2003: 257, fig. 61 A–H.— Bouillon et al, 2006: 399.

Synthecium elegans var. subventricosum .— Ralph, 1958: 347, fig. 16 a–h.— Watson, 1973: 167, figs 15, 16.— Watson, 2005: 535. Synthecium elegans .— Blackburn, 1942: 111 (in part).

Material examined. SAM H2535, preserved material; one microslide ( SAM H2588). Near South Australia – Western Australia border, depth 180 m, trawl, coll: R. Southcott 1/07/1988 .

Description. Three infertile stem fragments to 10 mm long on Zygophylax concinnus . Hydrorhizal stolon tubular, perisarc thick. Cauline hydrocladia opposite with up to 6 pairs of hydrothecae. Hydrocladial internodes long, narrowing to transverse, node usually indistinct or absent.

Hydrothecae opposite, distal on internode, basal pair slightly offset, long, tubular, of same diameter throughout, free adcauline wall about one third length of adnate adcauline wall, floor transverse, a small knot of perisarc at base of adcauline wall, margin circular, rim slightly outrolled, incipient replications in some hydrothecae.

Hydrorhiza, width 200–320 Hydrocladium

internode length 840–1060 width at node 104–168 Hydrotheca

width at floor 92–100 length adnate adcauline wall 464–496 length of free adcauline wall 128–176 diameter of margin 160–196 Remarks. See previous comments on the distinction between Synthecium elegans and Synthecium subventricosum .

Distribution. Southern Australia, New Zealand.