Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to

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234 often lost, some replaced by pseudophylactocarps. Auxiliary tubes can also bear pseudophylactocarps; they can also be present on sidebranches, sometimes they are rare or absent. Pseudophylactocarps are modified hydrocladia without hydrothecae, highly flexible, com- P. SCHUCHERT Fig. 75. Lytocarpia angulosa (Lamarck, 1816); A, Indonesia, Kei Islands collection; B–D, station 18; E, station 15. A. Distal fourth of a colony. B. Hydrocladial segment, note abcauline marginal tooth. C. Same hydrocladial segment seen from left and right, note differently shaped lateral nematothecae. D. Modified hydrocladium (pseudophylactocarp) from stem, same scale as C. E. One costa of a corbula seen from inner side. – Scales: A = 2 cm; B = 50 µm; C–D = 0.1 mm; E = 0.2 mm. posed of short segments, each segment with three nematothecae, these resembling to a pair of laterals and one median inferior nematotheca of normal hydrocladia. Axis of side-branches polysiphonic, monosiphonic at very ends only, with superficial pri-
HYDROIDS OF THE DANISH EXPEDITION TO THE KEI ISLANDS mary tube bearing alternate hydrocladia, base of side-branches without oblique pinching (hingejoint). Hydrocladia straight, stiff, dense, inclined towards hydrocaulus at an angle of about 60°, up to 5 mm long, with oblique nodes delimiting segments. The distal-most hydrocladia of a sidebranch can be transformed into spine-like processes bearing nematothecae. Hydrotheca semi-circular in side view, 0.21– 0.25 mm high, adcauline side 2/3 adnate, opening-plane parallel to hydrocladial axis, almost no free abcauline side, rim with a large abcauline tooth, lateral margin undulated, with a horizontal, thin abcauline septum projecting into lumen of hydrotheca, free end of septum in-rolled. Median inferior nematotheca adnate along entire length of abcauline hydrothecal wall, total length less than height of hydrotheca, free part of variable length, top side of free part open and thus gutter-like, opening into hydrotheca (foramen) present. Lateral nematothecae cupshaped, broad, opening facing upward; the two lateral nematothecae of on hydrothecae are often unequally developed, especially in more proximal hydrothecae (Fig. 75C). Gonothecae borne on hydrocladium modified into corbula. Corbula as long as hydrocladia, axis without hydrothecae, with two rows of alternate costae. Costae solitary and not fused, up to 1.3 mm long, each with a hydrotheca in lower part, distal part tapering, segmented, on lateral side of each segment two opposite, adnate nematothecae. Gonothecae attached below hydrotheca, lenticular to sac-shaped, 0.6 mm diameter; gonophore medusoid, bell margin with granules. Remarks The hydrotheca of Lytocarpia angulosa (Lamarck, 1816) resembles somewhat the one of Macrorhynchia phoenicea, but its abcauline tooth, the gutter-shaped median inferior nematotheca, and the frequently unequal development of the lateral nematothecae of L. angulosa are sufficient to distinguish them. The colony form of the two species is quite different and so they are easily separable macroscopically (cf. Figs 68A and 75A). Some of the examined gonothecae contain 235 gonophores that are clearly similar to the ones found in M. philippina, thus presumably liberable medusoids. The medusoids even have a ring of refringent granules along the bell margin. These medusoids are now known for quite a number of thecate hydroids (see Boero & Bouillon 1989, Gravier-Bonnet & Migotto 2000). Likewise, the pseudophylactocarps are found in various species of tropical aglaophenids belonging to different genera (see also L. perarmata below). Distribution Northern Australia, Indonesia. Type locality: Australia. Lytocarpia delicatula (Busk, 1852) Fig. 76. Plumularia delicatula Busk, 1852: 396. Aglaophenia delicatula Bale, 1884: 167, pl. 14: fig. 4, pl. 17: fig. 11. – Borradaile 1905: 843, pl. 69: fig. 7. – Billard 1913: 106, fig. 95. – Jäderholm 1920: 8, pl. 2: fig. 7. – Jarvis 1922: 350. – Pennycuik 1959: 185. – Watson 2000: 57, fig. 46A–E. Thecocarpus delicatulus. – Millard & Bouillon 1973: 94, fig. 11J–K. – Millard 1975: 455, 139D–E. Material examined: Kei Islands Expedition stations: 37, on sponge and stone. – 67, part of plume. – 85, with gonothecae. – Kei Islands Expedition, Banda Islands, Neira Island, 20 m, 1 Jun 1922, on sponge. Description Colony pinnate, 3–12 cm, stem not branched, monosiphonic, bearing alternate hydrocladia, with prosegments, with one or two hingejoints, part above hinge-joint segmented through slightly oblique nodes, each segment bearing a hydrocladial apophysis with a mamelon and three nematothecae: one inferior anterior and one on each side of the apophysis. Hydrocladia up to 8 mm long, held obliquely to caulus, bearing anterior hydrothecae, homomerously segmented by transverse nodes, segments with weakly developed internal ribs. Hydrotheca campanulate, depth 0.21–0.23 mm, covering nearly complete segment, adcauline side adnate; opening forming an angle of about 55° with segment, inclined towards below, margin with five cusps: one distinct abcauline
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Family Solanderiidae HYDROIDS OF TH
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Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to

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