Biostratigraphic and taxonomic studies were carried out to determine whether the fossil conchostracan record of the southern continents contained credible evidence of nonmarine dispersal between them during portions of Paleozoic and Mesozoic time. Fossil collections were made toward that end in the following: Africa, Cave Sandstone, Triassic of the Republic of South Africa and Lesotho; Australia, Newcastle Coal Measures, Permian (Tartarian); Antarctica, Ohio Range, Permian, and Queen Alexandra Range and southern Victoria Land, Lower Jurassic; India, Raniganj Formation, Upper Permian, Panchet Formation, Triassic, and Kotá Formation, Lower Jurassic; South America, Brazil, Rio do Rasto Formation, Upper Permian. Other conchostracan taxa were contributed and/or loaned by colleagues or museums, or came from the writer’s collections from Africa, Antarctica, Australia, India, and South America. These included conchostracan fossils from Morocco and Algeria, Carboniferous and Cretaceous; Angola, Triassic; Devonian and Jurassic of southern and northern Victoria Land, Antarctica, respectively; upper Paleozoic and Triassic of western and eastern Australian basins; the Cretaceous of Victoria, Australia, and the Tasmanian Triassic; the Mesozoic of Brazil, Chile, Argentina, Bolivia, Colombia, and Venezuela; and conchostracan-bearing cores from the Triassic of India. For all conchostracan taxa studied (where preservation permitted) a standardized series of measurements and ratios were used to facilitate inter- and intra-continental comparisons between species. Mitchell’s Australian conchostracan types are here revised and refigured, as are T. R. Jones conchostracan types from the southern continents (exclusive of Antarctica), as well as other taxa described in the older and modern literature.