(®gures 1j, 2p, q)
Description. Cell usually elongate elliptical and somewhat inēxible, 4±10 Mm long (mostly 6±9 Mm), 2±5 Mm wide. Two ¯agella unequal in length emerge subapically from a shallow pocket. The anterior ¯agellum appears inactive, is as long as or slightly shorter than the cell and is held forwards with a single anterior curve held perpendicular to the substratum. The acronematic posterior ¯agellum is typically directed straight behind the cell and is about 2.2±3.5 times the cell length. Cells swim in rapid darts in straight lines. Frequently observed. Description based on observations of 21 cells.
Remarks. This species has been found in North Atlantic, subtropical and tropical Australia, Brazil, Arctic Canada, Denmark, West Greenland, Hawaii, Gulf of Finland and Panama, and previously reported size ranges are 5±15 Mm (Larsen and Patterson, 1990; Vùrs, 1992a, 1992b, 1993a; Patterson et al., 1993; Ekebom et al., 1996; Patterson and Simpson, 1996; Tong et al., 1998). Generally, our observations are in accordance with those of previous observers. Bodo saliens is distinguished from other species of the genus Bodo by its rapid darting movement and the posterior ¯agellum which is directed in a straight line. This species is similar in shape to B. curvi ®lus Griessmann, 1913, but it is distinguished because B. curvi ®lus has a paddling anterior ¯agellum which is curved along its entire length.
Hemistasia phaeocysticola (ScherOEel, 1900) ElbraÈchter et al., 1996 (®gures 1k, 4a±e)
Description. Cell outline pyriform, about 13±15 Mm long, metabolic, with a ¯exible apical papillum and with an indistinct spiral groove. Two ¯agella insert subapically in a pocket, are unequal in length and wrap around the body during feeding. The posterior ¯agellum is slightly longer than the anterior ¯agellum and the cell. During swimming cells rotate. The cells often contain one large food vacuole up to 6 Mm in the posterior part of the cell. Observed eating the cytoplasm of diatoms. The nucleus was not seen. Rarely observed.
Remarks. According to ElbraÈchter et al. (1996), this species is identical with Hemistasia klebsii Griessmann, 1913 and Pronoctiluca phaeocysticola (ScherOEel, 1900) Pavillard, 1922. They observed this species inside the shells of diatoms, dinoāgellates and copepods, and in cultures the species attacked diatoms, dinoāgellates and prymnesiophytes. This species was found in marine sites by ScherOEel (1900), Griessmann (1913), ElbraÈchter et al. (1996) and Tong et al. (1998). Previous reported cell lengths range from 10 to 25 Mm. The genus Hemistasia resembles Entomosigma, Rhynchobodo and Cryptaulax. The latter two genera have recently been synonymized (Bernard et al., 1999). Hemistasia can be distinguished from Rhynchobodo by its anterior papillum. Hemistasia may be the same as the genus Entomosigma Schiller, 1925 (Patterson, 1994). Figure 3 of ElbraÈchter et al. (1996) is similar to ®gure 21 (I±II) of H. klebsii by Griessmann (1913) and the ®gures of Entomosigma peridinioides Schiller, 1925, and ®gures 5, 6 of ElbraÈchter et al. (1996) are also similar to the ®gure 3 of C. marina of Throndsen (1969). Cryptaulax marina sensu Throndsen, 1969 is believed to be H. phaeocysticola (Bernard et al., 1999).