They are found in pairs after cell division. Diplobacilli – Diplobacilli occur as two rods attached to one another.Bacillus – Bacillus bacteria occur as a single unattached cell that resembles a small rod.They can be divided into various sub-types, based on way the rod shaped cells are arranged: Bacillus bacteria typically occur in chains and are found in soil and water. Sarcinae – Sarcinae bacteria occur as groups of eight cells.īacilli are rod-shaped, gram-positive bacteria.Staphylococcus – In staphylococcus bacteria, cell division occurs in three different planes, arranging the cells in an irregular cluster that resembles a bunch of grapes.Tetrads – In tetrads, cell division occurs in two planes, arranging the cells in groups of fours.Streptococcus – After cell division, streptococcus cells join in a single plane in a chain-like arrangement.Diplococcus – The cells in diplococcus bacteria are arranged in pairs after cell division.Monococcus – Coccus bacteria exist as single spherical cells.Based on the cell arrangement, cocci bacteria can be classified into specific subtypes: After dividing, the cells remain attached to one another in distinctive arrangements by which they are identified. Spherical shaped bacteria - CoccusĬocci are spherical-shaped bacteria. Each bacterial species has a characteristic shape by which it is identified. There are four basic bacterial shapes – spherical, rod-shaped, comma-shaped, and helical.

Bacteria shapes and sizes