Minchin, the sporulating parasite becomes rounded off and forms a protective cyst, doubtless for the protection of the spores during dissemination.
In some forms (e.g. Haplosporidium and Rhinosporidium) the spore-mother-cells, instead of becoming each a single spore, as in Bertramia, give rise to several, four in the first case, many in the latter. Sometimes, again, the spore, while preserving the essentially simple character of the sporoplasm, may be enclosed in a spore-case; this may have the form of a little box with a lid or operculum, as in some species of Haplosporidium, or may possess a long process or tail, as in Urosporidium (fig. 15).
The Haplosporidia are divided by Caullery and Mesnil into three families, Haplosporidiidae, Bertramiidae and Coelosporidiidae; one or two genera are also included whose exact position is doubtful.
(a) Haplosporidiidae: 3 genera, Haplosporidium, type-species H. heterocirri; Urosporidium, with one sp., U. fuliginosum; all parasitic in various Annelids; and Anurosporidium, with the species A. pelseneeri, from the sporocysts of a Trematode, parasitic on Donax.
(b) Bertramiidae: 2 genera, Bertramia, with B. capitellae from an Annelid and B. asperospora, the Rotiferan parasite above described; and Ichthyosporidium, with I. gasterophilum and I. phymogenes, parasitic in various fish.
(c) Coelosporidiiae: genera Coelosporidium, type-species C. chydoriclola; and Polycaryum, type-species P. branchiopodianum. These forms are parasitic in small Crustacea. The genus Blastulidium is referred, doubtfully, by Caullery and Mesnil to this family; but certain phases of this organism seem to indicate rather a vegetable nature.
The genus Rhinosporidium should probably be placed in a distinct family. The only species so far described is R. kinealyi from the nasal septum of man, to which reference has above been made. Another form, Neurosporidium cephalodisci, agreeing in some respects with Rhinosporidium, has been described by Ridewood and Fantham (37a) from the nervous system of Cephalodiscus.
A parasite whose affinities are doubtful, but which is regarded by Caullery and Mesnil as allied to the Haplosporidia, is the curious parasite originally described by Schewiakoff as “endoparasitic tubes” of Cyclops; it has been named by Caullery and Mesnil, Scheviakovella. This organism is remarkable in one or two ways: it possesses a contractile vacuole; the amoeboid trophozoites tend to form plasmodia; and the spores, of the usual simple type, may apparently divide by binary fission.
5. There remain, lastly, certain forms, which are conveniently grouped together as “Sporozoa incertae sedis,” either for the reason that it is impossible to place them in any of the well-defined orders, or because their life-cycle is at present too insufficiently known. Serosporidia is the name given by Pfeiffer to certain minute parasites of the body-cavity of Crustacea; they include Serosporidium, Blanchardina and Botellus. Lymphosporidium, a form with distributed nucleus, causing virulent epidemics among brook-trout, is considered by Calkins (3) to be suitably placed here. Another parasite of lymphatic spaces and channels is the remarkable Lymphocystis, described by Woodcock (46), from plaice and flounders, which in some respects rather recalls a Gregarine. The group Exosporidia was founded by Perrier to include a peculiar organism, ectoparasitic on Arthropods, to which the name of Amoebidium had been given by Cienkowsky. It has recently been shown, however, that this organism is most probably an Alga. Another genus, Exosporidium, described by Sand (38), is placed at present in this group. For details of the structure of these forms and others like Siedleckia, Toxosporidium, Chitonicium Joyeuxella and Metschnikovella, a comprehensive treatise on the Sporozoa, such as that of Minchin, should be consulted.
To complete this article, it will be sufficient to mention various enigmatical bodies, associated with different diseases, which are regarded by their describers as Protozoa. Among such is the “Histosporidium carcinomatosum” of Feinberg, which he finds in cancerous growths. Cytoryctes, the name given to “Guarnieri’s bodies” in small-pox and vaccinia, has been recently investigated by Calkins (3a), who has described a complex life-cycle for the alleged parasite. Other workers, however, such as Siegel, give a quite different account of these bodies, and, moreover, find similar ones in scarlet-fever, syphilis, &c.; while yet others (e.g. Prowazek) deny that they are parasitic organisms at all.
Bibliography.—(For general works see under Sporozoa.) (1) Bertram, “Beiträge zur Kenntnis der Sarcosporidien,” Zool. Jahrb. Anat. 5, 1902; (2) L. Brasil, “Joyeuxella toxoides,” (n.g., n.sp.), Arch. zool. exp. N. et R. (3) 10, p. 5, 7 figs., 1902; (3) G. N. Calkins, “Lymphosporidium truttae,” (n.g., n.sp.), Zool. Anz. 23, p. 513, 6 figs., 1903; (3a) ib. The Life-History of Cytoryctes Variolae; Guarnieri, “Studies path. etiol. variola,” J. Med. Research (Boston, 1904), p. 136, 4 pls.; (3b) M. Caullery and A. Chappellier, “Anurosporidium pelseneeri, (n.g., n.sp.), Haplosporidie,” &c., C. R. soc. biol. 60, p. 325, 1906; (4) M. Caullery and F. Mesnil, “Sur un type nouveau” (Metchnikovella, n.g.), C. R. ac. sci. 125, p. 787, 10 figs., 1897; (5) ib. “Sur trois Sporozoaires parasites de la Capitella,” C. R. soc. biol. 49, p. 1005, 1877; (6) ib. “Sur un Sporozoaire aberrant” (Siedleckia, n.g.), op. cit. 50, p. 1093, 7 figs., 1898; (7) ib. “Sur le genre Aplosporidium” (nov.), op. cit. 51, p. 789, 1899; (8) ib. “Sur les Aplosporidies,” C. R. ac. sci. 129, p. 616, 1899; (9) ib. “Sur les parasites intimes des Annélides” (Siedleckia, Toxosporidium), C. R. ass. franç., 1899, p. 491, 1900; (10) ib. “Sur un type nouveau (Sphaeractinomyxon, n.g.) d’Actinomyxidies,” C. R. soc. biol. 56, p. 408, 1904; (11) ib. “Phénomènes de sexualité dans le développement des Actinomyxidies,” op. cit. 58, p. 889, 1905; (12) ib. “Recherches sur les Actinomyxidies,” Arch. Protistenk. 6, p. 272, pl. 15, 1905; (13) ib. “Sur quelques nouvelles Haplosporidies d’Annélides,” C. R. soc. biol. 58, p. 580, 6 figs., 1905; (14) ib. “Sur des Haplosporidies parasites de poissons marins,” ib. p. 640, 1905; (15) ib. “Recherches sur les Haplosporidies,” Arch. zool. exp. (4) 4, p. 101, pls. 11-13, 1905; (16) L. Cohn, “Über die Myxosporidien von Esox lucius,” Zool. Jahr. Anat. 9, p. 227, 2 pls., 1896; (17) ib. “Zur Kenntniss der Myxosporidien,” Centrbl. Bakt. 1, Orig. 32, p. 628, 3 figs., 1902; (18) ib. “Protozoen als Parasiten in Rotatorien,” Zool. Anz. 25, p. 497, 1902; (19) F. Doflein, “Über Myxosporidien,” Zool. Jahr. Anat. 11, p. 281, 6 pls., 1898; (20) ib. “Fortschritte auf dem Gebiete der Myxosporidienkunde,” Zool. Centrbl. 7, p. 361, 1899; (21) R. Gurley, “The Myxosporidia,” Bull. U.S. Fish. Comm., 1892, p. 65, 47 pls., 1894; (22) E. Hesse, “Sur une nouvelle Microsporidie tétrasporée du genre Gurleya,” C. R. soc. biol. 55, p. 495, 1903; (23) ib. “Thelohania légeri” (n.sp.), op. cit. 57, pp. 570-572, 10 figs., 1904; (24) ib. “Sur Myxocystis Mrazeki Hesse,” &c., op. cit. 58, p. 12, 9 figs., 1905; (25) A. Laveran and F. Mesnil, “Sur la multiplication endogène des Myxosporidies,” op. cit. 54, p. 469, 5 figs., 1902; (26) ib. “Sur la morphologie des Sarcosporidies,” op. cit. 51, p. 245, 1899; (27) ib. “De la Sarcocystin,” op. cit. p. 311, 1899; (28) L. Léger, “Sur la sporulation du Triactinomyxon,” op. cit. 56, p. 844, 4 figs., 1904; (29) ib. “Considérations sur ... les Actinomyxidies,” op. cit. p. 846, 1904; (29a) L. Léger and E. Hesse, “Sur une nouvelle Myxosporidie, Coccomyxa, n.g.,” C. R. ac. sci., 1st July 1907; (29b) ib. “Sur la structure de la paroisporale des Myxosporidies,” op. cit. 142, p. 720, 1906; (29c) A. Lutz and A. Splendore, “Über ‘Pébrine’ and verwandte Mikrosporidien,” Centrbl. Bakt. 1, 33, Orig. p. 150, 1903, and 36, Orig. p. 645, 2 pls., 1904; (29d) E. A. Minchin and H. B. Fantham, “Rhinosporidium kinealyi” (n.g., n.sp.), Q. J. Micr. Sci. 49, p. 521, 2 pls., 1905; (30) A. Mrazek, “Über eine neue Sporozoenform” (Myxocystis), S. B. Böhm. Ges. 8, 5 pp., 9 figs., 1897; (31) ib. “Glugea lophii,” Doflein, op. cit. 10, 8 pp., 1 pl., 1899; (32) C. Perez, “Sur un organisme nouveau, Blastulidium,” C. R. soc. biol. 55, p. 715, 5 figs., 1903; (33) ib. “Sur nouvelles Glugéidées,” op. cit. 58, pp. 146-151, 1905; (34) ib. “Microsporidies parasites des crabes,” Bull. sta. biol. d’Arcachon, 8, 22 pp., 14 figs., 1905; (35) W. S. Perrin, “Pleistophora periplanetae,” Q. J. Micr. Sci. 49, p. 615, 2 pls., 1906; (36) L. Plate, “Über einen einzelligen Zellparasiten” (Chitonicium), Fauna Chilensis, 2, pp. 601, pls., 1901; (37) M. Plehn, “Über die Drehkrankheit der Salmoniden” (Lentospora, n.g.), Arch. Protistenk. 5, p. 145, pl. 5, 1904; (37a) W. J. Ridewood and H. B. Fantham, “Neurosporidium cephalodisci, n.g., n.sp.,” Q. J. Micr. Sci. 51, p. 81, pl. 7, 1907; (38) R. Sand, “Exosporidium marinum” (n.g.,