Evolutionary trends in Lepidolina

    "Evolutionary increase in the diameter of the proloculus (initial chamber) of the fusulinid foraminiferan Lepidolina multiseptata. For each population, the horizontal line represents the range of sizes, and the black rectangle depicts the 95 percent confidence limits for the mean, which is inidcated by the vertical line. The six clusters of populations are in stratigraphic succession, but within each cluster, the vertical ordering of populations is aribtrary (From Ozawa, 1975)" [Stanely 1976]