Schizotricha unifurcata: Peña Cantero and Vervoort 1999, p 372 –373 (synonymy).
Material examined. 601/008, two incipient stems 25 and 20 mm high, and one distal stem fragment ca 30 mm long (USNM 1025620; RMNH-Coel. 30959).
Diagnosis. Colonies with branched stems. Main cauline tube with single hydrothecate internodes with two or three infrathecal nematothecae. Hydrocladia up to seventh order recorded. Hydrocladia heteromerously divided into internodes; with ahydrothecate internode, provided with two nematothecae, following cauline and hydrocladial apophyses. Unforked hydrocladial internodes with a single infrathecal nematotheca. Hydrotheca deep. Forked hydrocladial internodes with two to four infrathecal nematothecae.
Remarks. The material studied, composed of juvenile stems, is unbranched. The unforked hydrocladial internodes are provided with a single infrathecal nematotheca, though a second infrathecal nematotheca may be present in the two basalmost unforked hydrocladial internodes.
Ecology and distribution. Schizotricha unifurcata is a eurybathic species (Peña Cantero and Vervoort 1999). It has been collected at depths from 15 (Millard 1977) to 567 m (Stechow 1925) on muddy bottoms (Allman 1883); our present material comes from depths of 142– 160 m. Colonies with gonothecae were collected in January (Allman 1883), February (Peña Cantero et al. 1996), April (Millard 1977), and November (Stechow 1925).
Schizotricha unifurcata has an Antarctic-Kerguélen distribution (Peña Cantero 1998). In sub-Antarctic waters, it has been reported from off Kerguélen (Allman 1883; Naumov and Stepan’yants 1962; Millard 1977) and off Heard and McDonald Islands (Millard 1977). In Antarctic waters it has been found off Bouvet Island (Stechow 1925), at the limits of the Antarctic region, off Adélie Coast (Naumov and Stepan’yants 1972), in East Antarctica, and in the eastern part of the Weddell Sea (Peña Cantero et al. 1996). The present material was obtained off Shag Rocks in the South Georgia area, West Antarctica.