Most bacteria come in one of three basic shapes: coccus, rod or bacillus, and spiral. The cocci are spherical or oval bacteria having one of several distinct arrangements based on their planes of division.
Division in one plane produces either a diplococcus or streptococcus arrangement.
Based on planes of division, the coccus shape can appear in several distinct arrangements: diplococcus, streptococcus, tetrad, sarcina, and staphylococcus. The streptococcu arrangement gives an arrangement in chains