Volvox algae



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.







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