Phacus Dujardin, 1841 (ref. ID; 4492, 4950)
Order Euglenales (ref. ID; 4826)

[ref. ID; 1618]
Highly flattened; asymmetrical; pellicle firm; body form constant; prominent longitudinal or oblique striation; flagellum and a stigma; chromatophores without pyrenoid are discoid and green; holophytic; fresh water. (ref. ID; 1618)

[ref. ID; 3490]
The cell is rigid and ovate in front view and is provided with a short caudal process, conspicuously compressed and more or less twisted. The periplast is usually ornamented with longitudinal striae or lows of short spines. The chloroplasts are numerous and discoid, while the paramylum bodies are one or two and large ring-shaped. (ref. ID; 3490)

Phacus acuminata Stokes (ref. ID; 1618)
Description; Nearly circular in outline; longitudinally striated; usually one small paramylum body; flagellum as long as the body. (ref. ID; 1618)
Measurements; About 30-40 by 20-30 um. (ref. ID; 1618)
Phacus caudatus Hubner (ref. ID; 3490, 3517, 4950)
Description; The oblong species carrying a fairly elongate caudal process and having large and small paramylum bodies. (ref. ID; 3490)
Measurements; The examined specimen was rather small, being as long as 38 um and as broad as 18 um. (ref. ID; 3490)
Phacus curvicaudus Swir. (ref. ID; 4492)
Description; Cell 22-24 um, 16-18 um, contour triangular, thick, slightly twisted, both faces dividing by a median furrow in two different halves, one thicker and longer than the other. Ends rounded, posterior tapered to a short curved pointed cauda (1.5-2 um long). In apical view the cell present "S" or "8" shape. Pellicle longitudinally striated following the torsion of the cell. Two big spherical paramylon bodies, located one in each half of the cell. Cosmopolitan. (ref. ID; 4492)
Phacus helicoides Pochmann (ref. ID; 3517, 4492, 4950)
Syn; Phacus longicauda var. torta Lemm., 1900 (ref. ID; 4950); Phacus torta (Lemm.) Skv. var. tortuosa Skv., 1928 (ref. ID; 4950)
Description; Cell 95-100 um long, 48-50 um broad, cauda 30-32 um long, romboidal in frontal view, twisted. We could observe 16 striae on each face (5-6 in 10 um) mounted on an elevation of the pellicle which follows the torsion of the cell. Thinner transversal striae extend between these above mentioned (11-12 in 10 um). The torsion originated in the anterior end, extends along the whole cell and produces 4 helicoidal rotations. Cosmopolitan. (ref. ID; 4492)
Comment; In our opinion the specimen from Bolivia described as P. helicoides by Coute & Therezien (1994), could be P. sesquitortus on the basis of its torsions number. (ref. ID; 4492)
Phacus hispidula (Eichwald) (ref. ID; 3490) or (Eichwald) Lemm., 1910 (ref. ID; 4950)
See; Phacus hispidulus (ref. ID; 4950)
Description; The cell is ovate with a short caudal process and has hispidulous rows instead of striae, a flagellum as long as the cell and a single small paramylum particule. (ref. ID; 3490)
Phacus horridus Pochmann, 1942 (ref. ID; 4967, 4968) reported year? (ref. ID; 3517, 4492, 4950, 7591)
Description; Our observations of the ultrastructure of this species were similar to those described by Conforti & Tell (1983), Conforti (1994, 1998). Among the studied specimens we could observe two types of cell, ones broadly ovate and shorter than the others (30-32 x 21-22 um, cauda 5-6 um long), which presented a more elongate contour (45-47 x 23-24 um, cauda 7-8 um long). Cosmopolitan. (ref. ID; 4492)
The pellicle ultrastructure. (ref. ID; 7591)
Phacus lemmermannii (Swir.) Skvortzow (ref. ID; 4492, 4950)
Syn; Phacus alata Klebs var. lemmermannii Swirenko (ref. ID; 4950); Phacus alata Klebs var. major Drez. (ref. ID; 4950)
Description; Cell 42-45 um long, 25-29 um broad, triangular, twisted, with a longitudinal deep median furrow. Anterior end rounded slightly emarginate. Posterior end tapering into a straight or curved, acute cauda (3-4 um long). Pellicle with longitudinal striae (13-14 in 10 um) that follow the cell torsion. Cosmopolitan. (ref. ID; 4492)
Phacus longicauda (Ehrenberg) (ref. ID; 1618) or (Ehrenberg) Dujardin (ref. ID; 3517, 4950)
Syn; Euglena longicauda Ehrenberg, 1838 (ref. ID; 4950); Phacus longicaudaus (Ehrenberg) Butschli, 1889 (ref. ID; 4950)
Description; Usually slightly twisted; a long caudal prolongation; flagellum about one-half the body length; stigma prominent; many chromatophores; a discoidal paramylum body central; pellicle longitudinally striated. (ref. ID; 1618)
Measurements; 120-170 by 45-70 um. (ref. ID; 1618)
Phacus longicaudus (Ehrenberg) (ref. ID; 3490) or (Ehrenberg) Dujardin (ref. ID; 4492)
Description; The species is strongly twisted and has a long caudal process. (ref. ID; 3490)
Measurements; The cell 120 in length, 50 um in breadth and 40 um in length of a caudal process. (ref. ID; 3490)
Phacus monilata Stokes (ref. ID; 1618)
See; Phacus monilatus Stokes (ref. ID; 4950)
Description; A short caudal projection; pellicle with minute knobs arranged in longitudinal rows; discoid chromatophores; flagellum about the body length. (ref. ID; 1618)
Measurements; 40-55 by 32-40 um. (ref. ID; 1618)
Phacus oscillans Klebs (ref. ID; 1618, 4657, 4950)
Description; Rounded anteriorly and bluntly pointed posteriorly; striation oblique; one or two paramylum bodies; flagellum about as long as the body. (ref. ID; 1618)
Measurements; 15-35 by 7-10 um. (ref. ID; 1618)
Phacus pleuronectes O.F. Muller (ref. ID; 1618, 3490) or (O.F. Muller) Dujardin (ref. ID; 3517, 4950) reported author and year? (ref. ID; 4826)
See; Phacus dangeardii Lemm. (ref. ID; 4950)
Description; Short posterior prolongation slightly curved; a prominent ridge on the convex side, extending to posterior end; longitudinally striated; usually one circular paramylum body near center; flagellum as long as body. (ref. ID; 1618)
The cell is ovate with a short twisted caudal process and usually contains a large paramylum body. (ref. ID; 3490)
Measurements; 45-100 by 30-70 um. (ref. ID; 1618)
The size is variable, being as long as 30-53 um and as broad as 22-23 um. (ref. ID; 3490)
Phacus pyrum (Ehrenberg) (ref. ID; 1618) or (Ehrenberg) Stein (ref. ID; 4950)
See; Monomorphina pyrum (ref. ID; 3517)
Description; Circular in cross-section; with a medium long caudal prolongation; pellicle obliquely ridged; stigma inconspicuous; 2 discoidal paramylum bodies; flagellum as long as body. (ref. ID; 1618)
Measurements; About 30-50 by 10-20 um. (ref. ID; 1618)
Phacus rudicula (Playf.) Pochmann (ref. ID; 4492, 4950)
Description; Cell 21-22 um long, 12-14 um broad, clavate to pear shaped, asymmetrical, weakly flattened in apical view, 9-10 um thickness, anterior end rounded, posterior end narrowly tapered, with a moderate long, straight cauda (10-14 um). Pellicle with 7-9 spirally ribs, twisted to the left, concavely depressed between adjacent ribs, which born in the flagellar pore. Australia, Europe, South America. (ref. ID; 4492)
Phacus torta Lemmermann (ref. ID; 1618)
Description; Body twisted, with a long caudal prolongation; longitudinal striae on pellicle; chromatophores discoid; one large circular paramylum body; flagellum about one-half the body length. (ref. ID; 1618)
Measurements; 80-100 by 40-45 um. (ref. ID; 1618)
Phacus triqueter (Ehrenberg) (ref. ID; 3490) or (Ehrenberg) Dujardin, 1841 (ref. ID; 4967) reported year? (ref. ID; 3517, 4950)
Description; The compressed cell has the rigid periplast ornamented with characteristic raisen striae and a short caudal process. (ref. ID; 3490)
Measurements; Only a single specimen 50 um long and 40 um broad. (ref. ID; 3490)
Phacus trypanon Pochmann, 1942 (ref. ID; 4492) reported year? (ref. ID; 4950)
Description; The cells observed in our materials were shorter than those described by Pochmann (1942), 20.5-21 um long, 15-16 um broad, clavate to pear shaped, clearly depressed in apical view, 8-9 um thickness. Pellicle with ribs spirally striated to the left, which born in the flagellar pore and surround the body to the tail point. The posterior end tapers gradually to a straight pointed cauda. Africa, Bolivia, Europe, Guadaloupe. (ref. ID; 4492)
Phacus ulula Pochmann, 1942 (ref. ID; 4492) reported year? (ref. ID; 4950)
Description; Cell broadly ovate in frontal view, depressed in lateral view. Anterior end broadly rounded, lateral margins weakly undulate, posterior end broadly rounded with a short (2-3 um), rounded, slightly curved cauda. Pellicle with ribs spirally striated to the left, concavely depressed between adjacent ribs. Two large, lateral, parietal, cup shaped paramylon bodies, each 12-13 um long. Europe. (ref. ID; 4492)
Measurements; Our specimens were shorter than those described by Pochmann (1942) 16-17 um long, 15-16 um broad. (ref. ID; 4492)