This group, referred to as the true
bacteria,represents a large number of species. All of these bacteria have thick
and rigid cell walls. Some of the species are nonmotile (nonmoving), while
others are motile, using flagella or a sling motion to move from place to place.
Species belonging to the eubacteria are identified by their shapes. The
rod-shaped bacteria are known as bacilli (bacillus, sing.), the round bacteria
as the cocci (coccus, sing.), and the spiral-shaped as spirillae (spirillum,
sing.). Some species typically remain attached: diplococci occur in pairs,
streptococci in chains, and staphylococci in clusters.
