Bacteria are usually one of  three shapes: round (cocci), rod (bacilli), or wavy (spirochetes/spirillae/vibrio). Images 1 and 2 contain all three shapes of bacteria. Images 3 and 4 show cocci and bacilli together. Genera that are examples of round or spherical bacteria are Staphylococcus and Streptococcus . Escherichia coli and Bacillus are rod-shaped bacteria. Treponema are spirochetes and Spirillum are wavy shaped-bacteria. All images are at 1000 X magnification.