Environmental Engineering Reference
In-Depth Information
and is relatively easy to see and the other
lies in a furrow around the centre of the
cell and is more difficult to visualise (see
Fig. 4.56).
the anterior with single emergent flag-
ellum but pointed at the posterior end,
the point being of variable length. There
are numerous disc-shaped chloroplasts
without pyrenoids, and an eyespot (may
not be obvious). Disc-shaped paramy-
lum bodies (one to many) are present.
The pellicle is rigid and longitudinal stri-
ations and granules may be visible on
the surface. Common in ponds and other
still waters, tychoplanktonic, especially
where enriched with organic matter such
as swamps. Numerous species. Eugleno-
phyta. Plate XV. Fig. 4.51b.
109 (108) (a) Cells with a single emergent flagellum
.................................. 110
(b) Cells with two or more emergent flag-
ella............................... 114
110 (109) (a) Cells enclosed in a brownish test (see
Glossary) of various shapes with the flag-
ellum emerging from an anterior aperture
....................... Trachelomonas
(b) Cells not flattened or leaf-like . . . 112
Trachelomonas isfreeswimminganduni-
cellular. The cells, which are Euglena -
like, are enclosed in a roundish (although
there are many variations on this shape)
test, lorica or theca which may range
from pale to dark brown in colour and
is usually opaque. The surface of the test
may be smooth, granulate or spiny. The
single flagellum emerges from a round
aperture at the anterior end. A red eye-
spot is present. There are two to many
disc-shaped chloroplasts. Small paramy-
lum bodies may be present. Found mainly
inshallowwaters, ditches andponds, often
as a tychoplankter, but may occur in larger
water bodies. May be abundant enough to
form blooms colouring the water brown-
ish. Many species separated on the basis
of the shape and ornamentation of the test.
Euglenophyta. Plate XV.
112 (111) (a) Cells roughly cylindrical or fusiform,
often showing metaboly (see Glossary)
............................. Euglena
Euglena cells are solitary and free swim-
ming. They are usually elongated but may
bespindle-shapedortwisted.Theperiplast
may be flexible or firm and when firm
may, in some species, show spiral mark-
ings or rows of granules. Chloroplasts
one to many and variously shaped, disc-
shaped or stellate to band-like, depending
upon the species. Sometimes pyrenoids
are present. The emergent flagellum arises
from an apical reservoir. A prominent eye-
spot is present. Storage product is paramy-
lum and numerous granules of variable
shape may be present. Numerous species,
but identification to species level dif-
ficult. Common to abundant in ponds
and other shallow waters. Some species
found in acid waters. If present in large
numbers, Euglena can impart both taste
and odour to drinking waters (Palmer,
1962). Euglenophyta. Plate XV. Figs. 1.6
and 4.51c.
(b) Cells not enclosed in a test . . .... 111
111 (110) (a) Cells with pronounced dorsiventral
flattening (leaf-like in shape) often with
partofthecelltwisted.......... Phacus
Phacus is solitary and free swimming.
Cells are markedly flattened and may
be twisted along their length. Wide at
(b) Cells ovoid to pyriform and do not
show metaboly. . . . ................ 113
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