A category in a classification scheme for clusters of galaxies based on the contrast between the brightest member and the typical bright galaxies in the cluster. Class I clusters are dominated by an extremely large, luminous supergiant galaxy. In Class III, no member appears to stand out against the bright galaxy population. Class II is intermediate. The classification is named after the American astronomers Laura Patricia Bautz (1940–2014) and W. W. Morgan, who published it in 1970.