VOLVOX

CLASSIFICATION OF VOLVOX

Sub-division :- Algae

Class :- Chlorophyceae

Order :- Volvocales

Family :- Volvocaceae

Genus :- Volvox

Thallus is multicellular, motile and a coenobial colony.
Colonies are mostly spherical, rounded or oval in shape.
It is hollow in the centre and cells are arranged in a single layer towards the periphery.
Layer of cells is surrounded by a gelatinous mass which forms the outer and firm limiting layer.
The number of cells in a colony varies from 500-6,500 according to the species.
Each cell of the colony is connected with a few of the neighbouring cells by thin and delicate cytoplasmic strands.
Each cell is enveloped by an individual gelatinous sheath.
All the cells of a colony are typically chlamydomonad in shape, size and structure.
Each vegetative cell is biflagellate, motile and ovoid. The two flagella are anteriorly inserted. A contractile vacuole is situated one each at the base of a flagellum.
Cup-shaped chloroplast occupies much of the posterior part in which is situated a single pyrenoid. In the cavity formed by cup-shaped chloroplast lies a single nucleus, surrounded by cytoplasm.
Cytoplasm is rich in volutin grains. Eyespot or stigma occupies anterio-Iateral position.

Sub-division– Algae
1. Presence of a simple thallus.
2. Chlorophyll present
3. Cell wall made of cellulose.
Class – Chlorophyceae
1. Presence of a definite nucleus
2. Chloroplast present. grass green colour
3. Presence of starch
4. Reproductive structure motile and flagella equal in length.
Order – Volvocales
1. Vegetative cells flagellated
2. Thallus motile.
Family – Volvocaceae
1. Thallus colonial
2. Division of cells in longitudinal plane.
Genus – Volvox
1. Colony spherical or sub-spherical,
2. Number of cells at least 500.