Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to

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228 based his description of Lytocarpia graffei on a small, juvenile colony. The colony was monosiphonic and had no gonothecae. It must be considered as unrecognizable. Stechow (1919) distinguished it from M. balei on account of the shape of the bottom of the hydrotheca: rounded in M. balei, with a step in Lytocarpia graffei. This character is of little use, as usually all intermediates can be found in Macrorhynchia colonies. Leloup (1930b) also contested Stechow’s view, however, Leloup’s (1930b: fig. 6) material of M. balei appears indistinguishable from M. philippina because his figures show a thick, triangular intrathecal septum. Hirohito (1983, 1995) again described Japanese material of M. balei. Hirohito distinguished his material from M. philippina solely on account of the length and thickness of the intrathecal septum. However, the figures of M. philippina given by Hirohito (1983, 1995), are more typical for M. balei: the upright lateral nematotheca and the numerous gonothecae on the phylactocarps. Because Hirohito (1983) also described female gonothecae containing planulae, thus being larviparous and not releasing medusoids as seen in typical M. philippina, it seems more likely that this material was also M. balei. Hirohoto’s material should be re-examined for the presence of nematopores. Distribution Hawaii, Indonesia, Philippines, Japan. Type locality: Off south coast of Molokai, Hawaiian archipelago, 86–210 m. Macrorhynchia singularis (Billard, 1908) Fig. 72. Plumulariidae spec. IV von Campenhausen 1896b: 317, pl. 15 fig. 5. Lytocarpus philippinus var. singularis Billard, 1908b: 112, figs A–B. Lytocarpus singularis Billard, 1913: 79, figs 64–65. Lytocarpus balei. – In part Stechow 1909: 99, pl. 6: fig. 12. – Stechow 1919: 134. Material examined: Kei Islands Expedition stations: 18. – 40. – Kei Islands Expedition, Bay of Ambon, 45–90 m, 2 Mar 1922. – Kei Islands Expedition, Bay of Ambon, 90 m, 2 Mar 1922. Differential diagnosis Similar to Macrorhynchia philippina, but colo- P. SCHUCHERT Fig. 72. Macrorhynchia singularis (Billard, 1908); station 40. A. First internode of hydrocladium, note enlarged lateral nematotheca (dotted: nematocyst). B. Second segment of hydrocladium with characteristic thick median inferior nematotheca. – Scale: A–B 50 µm. nies smaller (up to 10 cm), one lateral nematotheca of first hydrocladial segment much enlarged and directed towards rear, opposite nematotheca of same segment small, free part of median nematotheca very short; median nematotheca of segments distal to first one mostly much enlarged and thick, lateral nematothecae usually small. Some lateral nematothecae of more distal segments can also be enlarged on one side, as well as some median inferior nemat-
HYDROIDS OF THE DANISH EXPEDITION TO THE KEI ISLANDS othecae can be short. Hydrothecal margin with two broad lateral lobes or irregular, abcauline side with pointed tooth. Remarks Billard (1908b) first regarded M. singularis as a variety of M. philippina, but in his 1913 publication he raised its status to the species level. Macrorhynchia singularis indeed resembles M. philippina, but the unilaterally hypertrophied lateral nematothecae as well as the alternately extremely short or very thick median inferior nematothecae make this morphotype rather distinct and easy to recognize (Fig. 72A–B). Stechow (1919) found Japanese material from Sagami Bay that only partially matched Billard’s description. It had one enlarged lateral nematotheca on the first segment, but the median inferior ones were normal. Stechow (1919) made some comments that let one suspect that he doubted somewhat the validity of M. singularis. In his survey of the thecate hydroids of Sagami Bay, Hirohito (1995) did not include M. singularis. Distribution Indonesia, ?Japan. Type locality: Salawati Island, NW New Guinea, 1.701°S, 130.785°E, 32 m. Monoserius pennarius (Linnaeus, 1758) Fig. 73. Sertularia pennaria Linnaeus, 1758: 813. Aglaophenia spicata Lamouroux, 1816: 166. – Billard 1909: 329. Plumularia Banksii Gray, 1843: 294. – Billard 1910: 48. Aglaophenia secunda Kirchenpauer 1872: 35, pl. 1: fig. 15, pl. 2: fig. 15, pl. 3: fig. 15. – Marktanner-Turneretscher 1890: 273. – Billard 1909: 329. Aglaophenia crispata Kirchenpauer, 1872: 36, pl. 1: fig. 16, pl. 2: fig. 16, pl. 3: fig. 17. – Billard 1909: 329. Not Aglaophenia spicata. – Kirchenpauer 1872; 27, pl. 1: fig. 12, pl. 2: fig. 11, pl. 4: fig. 11, [= A. cupressina Lamouroux, 1816]. Lytocarpus secundus. – Allman, 1883: 42, pl. 14. – Jäderholm 1903: 298. – Billard 1908c: 940. Lytocarpus fasciculatus Thornely, 1904: 123, pl. 3: figs 3, 3A, 3B. Lytocarpus pennarius. – Billard 1909: 329. – Ritchie 1910a: 19, pl. 4: fig. 2. Hemicarpus fasciculatus. – Billard 1913: 83, figs 68–69, pl. 5: figs 41–42. Hemicarpus banksi. – Bale 1924: 263, fig. 17a. 229 Monoserius fasciculatus. – Leloup 1932: 165, fig. 28. – Vervoort 1941: 228. Monoserius banksii. – Ralph 1961b: 56, fig. 8h Monoserius pennarius. – Mammen 1967: 307, figs 108–109. Monoserius fasciculatus. – Mammen 1967: 310. Material examined: Kei Islands Expedition stations: 65, incipient gonocladium present. – 67, with male gonothecae. – 69. – 70. – 83. – 102. – 103. – 105. – 110. – 114. – Kei Islands Expedition, Samalon Island, Ujungpandang, Sulawesi, 35 m, 28 Jun 1922. – Kei Islands Expedition, Taka Bako, Ujungpandang, Sulawesi, 25 m, 27 Jun 1922. Description Colonies forming single stems, rooted in sediment by a tangled mass of fibre-like stolons, stem height reaching 100 cm and more, flexible, limp when out of water. Stem polysiphonic, with regularly spaced pinnate side-branches. Basal part of stem in younger colonies pinnate through alternate hydrocladia, hydrocladia arise from superficial primary tube; in more distal part where there are pinnate side-branches and in larger colonies without pinnate base there is no primary tube, stem thus formed by auxiliary tubes only. Sidebranches originate from auxiliary tubes of main stem, feather-like through dense hydrocladia, side-branches alternate, in two rows, the two rows forming an angle of 90° or less, sidebranches thus directed towards one side (depending on view). Axis of side-branches polysiphonic but thinning to monosiphonic, with superficial primary tube bearing alternate hydrocladia. Primary tube with short apophyses for hydrocladia, each apophysis associated with three nematothecae: one on apophysis, one on side, one below. Hydrocladia straight, stiff, dense, inclined towards hydrocaulus at an angle of about 40°, with or without transverse nodes delimiting segments, spacing of hydrothecae variable: hydrothecae either slightly overlapping (Fig. 73C) or well separated (Fig. 73D). Internal ribs not much developed, usually two originating from rear wall of hydrotheca. Hydrotheca campanulate, nearly parallel to hydrocladial axis, 0.27–0.35 mm high, diameter at rim 0.15–0.17 mm, adcauline side completely adnate, opening-plane perpendicular to hydrocladial axis, rim with a large abcauline tooth and 4–5 triangular cusps on both lateral sides. Marginal abcauline tooth rectangular in frontal view,
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Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to

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