Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to

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180 environmental conditions can be assumed to be virtually identical, the morphological differences do certainly reflect genetic differences and not phenotypic variations. These presumably genetic differences of sympatric specimens were considered due to two different species being involved. At closer examination, both species are reliably distinguishable using the differences given in the diagnosis above. The most important characters to distinguish S. punctogonagia from S. sibogae are the subopposite hydrothecae, the curved convex free adcauline wall of the hydrotheca, and the smooth gonotheca. As for S. sibogae, the hydrothecal margin in this species is also very thin and flimsy and it is not entirely clear whether the species belongs to Salacia or Dynamena. Salacia punctagonangia is here recorded for the first time for Indonesia. It was previously only known from the Philippines. Hirohito (1995, as Salacia sp.) compares a Salacia species from Sagami Bay (Japan) with Salacia sibogae from the Indian Ocean. This Japanese material, although infertile, shows all characteristics of S. punctagonagia and is likely to belong to this species. Distribution Philippines, Indonesia, ? Japan. Depths: 120– 400 m. Type locality: Batan, Philippines, 120– 274 m. Salacia sinuosa (Bale, 1888) Fig. 36. Thuiaria sinuosa Bale, 1888: 772, pl. 18: figs 9–10. – Ritchie 1911: 844, pl. 85: fig. 4. Salacia sinuosa. – Billard 1925b: 204, fig. 48, pl. 8: fig. 29. – Watson 2000: 22, fig. 17E. Material examined: Kei Islands Expedition station 74, without gonothecae. Description Colony large, bush-like, up to 25 cm high, much branched, trunk at base up to 3 mm thick and woody, strongly polysiphonic through overgrowth of stolon-like tubes, only distal-most tips monosiphonic, ultimate branches pinnate, pinnate parts up to 5 cm long, stem of pinnate P. SCHUCHERT Fig 36. Salacia sinuosa (Bale, 1888). A. Teminal part of branch with base of hydrocladium B. Part of hydrocladium seen from broad side. – Scales: A = 0.5 mm; B = 0.2 mm. regions also polysiphonic. Stolons forming a root-like structure which anchors colony in sediment. Monosiphonic distal ends of stem with transverse nodes, segments short, each with three hydrothecae and an apophysis, a single hydrotheca opposite apophysis, two on side of apophysis. Hydrothecae of stem in two lateral rows, alternate, not in contact vertically or horizontally. Apophysis inserted between two successive hydrothecae of a segment, node to hydrocladium twisted. Hydrocladia stiff, straight, flattened, only occasionally a node present, with two lateral rows of overlapping hydrothecae. Hydrothecae of one row adjacent, oblique, overlapping for about 1/3
HYDROIDS OF THE DANISH EXPEDITION TO THE KEI ISLANDS of length. Hydrothecae of the two rows not in contact, in opposite to subopposite pairs. Hydrotheca tubular, narrowing from base to margin; adcauline wall 0.47–0.50 mm, almost completely adnate, only a very short upper rim free; lower half of abcauline side adnate to previous hydrotheca, free abcauline side mostly straight, nearly parallel to hydrocladium axis, 0.18–0.20 mm long, below margin a perisarc thickening and sometimes with a short inward fold; opening in frontal view ovate, openingplane parallel to hydrocladial axis or somewhat tilted towards below. Operculum a single valve attached to abcauline margin of hydrotheca, often several ones present. Below the side of some hydrothecae a round fenestration. Gonothecae not observed, according to Watson (2000) oblong, up to 1.5 mm long, width up to 0.54 mm, inserted between the rows of hydrothecae, wall smooth or with faint annulations, aperture on short neck at distal end. Colour of preserved material: stem dark brown, upper branches and hydrocladia light brown. Distribution Subtropical Australia, Indonesia. Type locality: Port Molle, Australia. Salacia tetracythara Lamouroux, 1816 Fig. 37. Salacia tetracythara Lamouroux, 1816: 212: pl. 6: fig. 3a–c. – Billard 1925b: 202, fig. 47, pl. 3: figs 27–28. – Mammen 1965: 54, fig. 87. – Rees & Vervoort 1987: 103, fig. 6d. – Gibbons & Ryland 1989: 414, fig. 31. – Hirohito 1995: 183, fig. 60a–c. – Watson 2000: 23, fig. 18A-F. Thuiaria fenestra Bale, 1884: 116, pl. 7: fig. 7, pl. 9: fig. 14. Calyptothuiaria opposita von Campenhausen, 1896b: 312, fig. 7. Material examined: Kei Islands Expedition stations: 69. – 71. – 72, with gonothecae. – 91. – 104, with gonothecae. – 106. – 107. Description Colonies erect, pinnate, up to 6 cm in present material (reportedly up to 10 cm), sometimes neighbouring shoots connected through distal tendrils of hydrocladia. Stems mostly unbranched, monosiphonic or polysiphonic, peri- 181 Fig. 37. Salacia tetracythara Lamouroux, 1816; station 72. A. Part of stem and base of hydrocladium. B. Hydrocladium in side view and attached gonotheca. – Scale: A–B = 0.2 mm. sarc thick, nodes only visible in distal regions, two lateral rows of hydrothecae, these not in contact, in subopposite pairs, three between successive hydrocladia of one side, apophyses for hydrocladia short, mostly delimited by node from hydrocladium. Hydrocladia in one plane, alternating, straight, stiff, length variable, held at approximately 60°–80° to stem, occasionally branching 2–3 three times, with numerous hydrothecae, nodes rare, distal end occasionally transformed into stolon-like tendril. Hydrothecae in two lateral rows, in opposite to subopposite pairs, members of a pair not in contact, successive hydrothecae of a row in contact and overlapping. Hydrotheca tubular, adnate for 9/10 of their adcauline length, proximal half to 2/3 of adcauline side straight, remaining part curved so that opening slightly tilted downward, abcauline side straight for nearly its entire length, length
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