151. Synedra undulata (Bail.) Greg. (Pl. 2, Fig. 9.) Greg. 1857, 531, 14, 107. Cupp 1943, 181. Toxarium undulatum Bail. 1854, 15, 24–25. Synedra undulata Bail. in Grun. 1861, 74. Cells stipitate, solitary; frustule very long and narrow, slightly inflated central portion and extremities; margins undulate; striae in valve view marked, perpendicular to margin; no central area; pseudoraphe indistinct. Length, 300μ. Distribution. Estuarine-neritic, tropical, marine. Epontic; found on fouling test plates. Australia: Heron Island, Moreton Bay. New Zealand: Dunedin. 152. Synedra fulgens (Grev.) W. Sm. (Pl. 2, Fig. 10.) W. Sm. 1853, 74, 12, 103. Boyer, 1927(a), 208. Exilaria fulgens Grev. 1827, Pl. 291. Licmophora fulgens Kütz. 1844, 123, 13 5. Ardissonia fulgens (Grev.) Grun., in Cl & Grun. 1880, II, 17, 108. Cells solitary, usually attached by a mucous pad, forming irregular, tufted colonies; valves linear, with slightly inflated central area, apices cuneate; valve surface with fine transverse striae, median line indistinct. Length, 100–750μ, breadth, up to 35μ. Distribution. Estuarine-neritic; marine. Epontic on rocks and plants, and on fouling test plates. Rare in plankton hauls. Australia: abundant in Moreton Bay, Port Stephens, Port Jackson, Botany Bay, Port Hacking, Eden. New Zealand: Hauraki Gulf and Auckland Harbour. 153. Synedra ulna (Nitzsch) Ehr. (Pl. 2, Fig. 11a, b.) Ehr. 1838, 211. Boyer, 1927 (a), 198. Cleve-Euler, 1953a, 60. Bacillaria ulna, Nitzsch, 1817, 99. Cells stipitate, colonial; frustules in valve view linear, suddenly constricted towards extremities; pseudoraphe distinct; striae transverse, median area quadrangular. Length, 280–320μ. Distribution. Fresh to brackish water. Epontic. Australia: Head of Port Hacking, Lake Macquarie, Conjola, Lakes Entrance, Nepean River. Previously recorded from Australia by Ralfs. (1861), Boyer (1927a). New Zealand: Auckland Harbour, Wellington (Wainui), Wellington Harbour. 154. Synedra splendens Kütz. (Pl. 2, Fig. 12a, b.) Kütz. 1844, 66. Boyer 1927(a), 199. Valves linear, elongate, swollen and rounded at ends; differs from S. ulna in the rounded apices. Distribution. Australia: Heron Island. 155. Synedra closteroides Grunow var. jährnefelti Mölder, 1939. (Pl. 2, Fig. 13.) In Cleve-Euler, 1953a, 60. Cells attached by a mucous pad, forming clustered colonies; frustules in valve view more or less sigmoid, with inflated centre and gently tapering apices; striae transverse, longitudinal median line very fine; a very small species; Length 35μ. Distribution. Estuarine, stenohaline, brackish (up to 2.5 per cent salt). Epontic. Australia. Lake Macquarie. 156. Synedra gaillonii (Bory) Ehr. (Pl. 2, Fig. 14.) Ehr. 1838, 17. Grun. 1862, 87. Boyer. 1927(a), 204. Cleve-Euler 1953(a), 60, 281. Synedra gallionii W. Sm. 1853, 74, 30, 265. Synedra gaillionii Hend. 1951, 36, 3. Navicula gailloni Bory, 1822, 24. Cells colonial, stipitate; frustules in valve view linear-oblong, gently curved and tapering slightly; the curvature is characteristic of New South Wales specimens; pseudoraphe distinct; valve surface with transverse, marginal, moniliform striae. Length, 100 to 150μ. Distribution. Estuarine; marine. Epontic on algae, Zostera, Posidonia,, etc., and from fouling test plates; very common, occurring in large numbers. Australia: Heron