TRIGONOSTOMUM AUSTRALIS SP. NOV.

(FIGS 5D, 9D, 10D; TABLE 1)

Alternative species name: trigonostomum-australis sp. nov.

Holotype: Whole mount, Australia, Queensland, North Stradbroke Island, Point Lookout, algae in tidepool, 12 August 1996.

Other material: Observations on live material. Two whole mounts from Australia, New South Wales, Arrawarra, on Sargassum sp., 28 August 1996 and 1 November 1997 .

Etymology: Reflects the species’ occurrence in the southern hemisphere.

Diagnosis: Trigonostomum species with coiled copulatory organ, with three whole spires. Stylet 414– 445 Mm long, enveloped by the mantle over its entire length. Mantle distally split into two spiny plates with terminal hook. Bursal appendage 34 Mm long, proximally curved over 270∞ and with straight distal section.