Astasia Dujardin, 1841 (ref. ID; 4950) reported year? (ref. ID; 1618), Ehrenberg (ref. ID; 3490) or Ehrenberg em. Dujardin (ref. ID; 3517)
Order Euglenales (ref. ID; 4826)

[ref. ID; 1618]
Body plastic, although ordinarily elongate; fresh water or parasitic (?) in microcrustaceans. (ref. ID; 1618)

[ref. ID; 3490]
The cell is free swimming and has a single flagellum. (ref. ID; 3490)

Astasia acus Christen. (ref. ID; 1618)
Description; Body form resembles Euglena acus, but without chromatophores and stigma; paramylum bodies; fresh water pond. (ref. ID; 1618)
Measurements; 61-68 by 6.5-8 um. (ref. ID; 1618)
Astasia klebsi Lemmermann (ref. ID; 1618), klebsii Lemmermann (ref. ID; 3517, 4950)
Description; Spindle-form; posterior portion drawn out; flagellum as long as the body; plastic; saprozoic; paramylum bodies oval; stagnant water. (ref. ID; 1618)
Measurements; 40-50 by 13-20 um. (ref. ID; 1618)
Astasia lagenula Schewiakoff (ref. ID; 3490, 4950)
Description; The cell is elongate with a rounded posterior end, being 45 um long and 10 um broad, and has a flagellum more or less longer than the body length, ovoidal paramylum granules and a somewhat large reservoir. (ref. ID; 3490)
Astasia longa Pringsheim (ref. ID; 3517, 4211, 4950)
Syn; Astasia chattonii Lwoff & Dusi (ref. ID; 4950)
Description; Swimming cells of Astasia longa are usually elongated with surface striations running parallel to the cell's long axis or showing slight coiling sinistrally or dextrally. When cells round up, the cell body diameter approximately doubles, the striations always coil sinistrally, and the almost spherical cells have several hollows. The distance between adjacent striations is greatest in the middle part of the cell and decreases at both ends. At the anterior tip, the 40 striations run continuously into the reservoir while this number gradually declines towards the posterior tip. In cross sections, the pellicle of A. longa resembles that of Euglena gracilis, having a ridge and groove configuration, four distinguishable microtubules, and a cisterna of tubular endoplasmic reticulum between adjacent grooves. (These grooves correspond to the surface striations). Elongated and rounded cells are not detectably different. Fragments of isolated pellicle curl up with the cytoplasmic surface inside. The ridge-groove configuration is retained together with all microtubules except, in some cases, microtubule 4. Tannic acid increases the contrast and apparent thickness of the pellicular strips and enhances an electron-dense projection from the pellicular strip that is associated with microtubules 1. Despite treatment with 1% Triton X-100, the plasma membrane remains morphologically intact except at the groove regions. Thick sections show that traversing filaments connect adjacent grooves, and shorter filaments are sometimes observed connecting grooves and ridges. Tangential sections show that the traversing filaments run almost perpendicular to the long axis of the pellicular strip, with adjacent filament sometimes crossing over. Longitudinal sections reveal two different periodic structures at the sides of the groove. One, with a periodicity of about 14 nm, consists of the projections observed between the groove and microtubule 1. The other, with ca. 19-nm periodicity, consists of the ends of the traversing filaments where they connect to the pellicular strip on the other side of the groove. (ref. ID; 4211)
[Elongated versus rounded cells]: Rounded and elongated cells were compared for evidence of either oblique distortion with in strips or sliding between strips, two alternative explanations for the surface particle movements of E. fusca (Suzaki & Williamson, 1985). The pellicular strips themselves lack ultrastructural features to assess their distortion but the plasma membrane overlying the ridges has numerous particles in tilted rows. Cell rounding-up did no significantly change the angle to these rows (mean angle of 42.9 +/- 5.7 degrees in elongated cells for n = 11 and 42.4 +/- 7.1 degrees rounded cells for n = 17). In contrast, the traversing fibers linking adjacent grooves are transverse in pellicular sheets prepared from elongated cells but oblique in sheets from rounded cells. (ref. ID; 4211)
Astasia margaritifera Schmarda (ref. ID; 3490)
Description; The cell is strongly metabolic, usually elongate fusiform and more or less flattened. The flagellum is shorter than the body length. The paramylum granules are numerous and rod-shaped. The metabolic flagellate pale bluish in the body and pale reddish in the reservoir. (ref. ID; 3490)