Suggested Changes in “A Revised Classification of the Phylum Protozoa”, with Particular Reference to the Position of the Haplosporidans

The obstacles which have prevented the haplosporidans from fitting into the classification prepared by the Committee on Taxonomy and Taxonomic Problems of the Society of Protozoologists have no objective basis but are essentially semantic in nature. The resemblance between the different kinds of filaments in spores is largely verbal. Therefore, the notion that the presence or absence of a “filament” is the essential character for segregating different groups of sporozoans into subphyla should be rejected. Then, if the subphylum names Sporozoa Leuckart, 1879, and Cnidospora Doflein, 1901, are replaced with the appropriate ones, Rhabdogena Delage and Hérouard, 1896, and Amoebogena Delage and Herouard, 1896, all obstacles to putting the order Haplosporida Caullery and Mesnil, 1899, into a satisfactory position are removed. Likewise, it then becomes logically possible to put the order Paramyxida Chatton, 1911, into the classification. Accordingly, these two orders are placed in subphylum Amoebogena, in classes Microsporea Corliss and Levine, 1963, and Myxosporea Bütschli, 1881, respectively. The latter class, having two groups of orders which are in sharp contrast to each other with respect to structural complexity, is here divided into two subclasses, Myxosporia Bütschli, 1881, (with orders Myxosporida Bütschli, 1881, and Actinomyxida Stole, 1889) and Paramyxia (with orders Paramyxida Chatton, 1911, and Helicosporida Kudo, 1931). It is suggested that the older name Sporozoa Leuckart, 1879, be used (after appropriate change of ending) to replace the class name Telosporea Schaudinn, 1900, and that the latter be discarded.