Fresh-Water Rhizopods of North America: Plate 10
This is Plate 10 in "Fresh-Water Rhizopods of North America." All of the figures belong to one species, Difflugia pyriformis. This rhizopod has a test ("shell") that is made up of foreign particles such as grains of sand that are held in shape by secretions from the organism.
Three other lithographic plates from "Fresh-Water Rhizopods of North America" (1897) are also available: