The classification of the Sarcosporidia as proposed by R. Blanchard, which was based on their various habitats, can no longer hold, because the same species may occur in the muscles as well as in the connective tissue. For the present, the few species that are known may be placed in one genus, _Sarcocystis_, Ray Lankester, 1882. The following species of _Sarcocystis_ are of interest:-- _S. miescheriana_, Kühn, 1865, in the pig. _S. bertrami_, Doflein, 1901, in the horse. _S. tenella_, Railliet, 1886, in sheep. _S. tenella bubali_ in buffaloes in Ceylon and Egypt. _S. blanchardi_, Doflein, 1901, in cattle. _S. muris_, Blanchard, 1885, in the mouse, to which it is lethal. _S. hueti_, Blanchard, 1885, in the seal. _S. colii_, Fantham, 1913, in the African mouse-bird, _Colius erythromelon_. Also various Sarcosporidia from antelopes, monkeys, opossum, birds, the gecko and wall-lizard are known. The spores of _S. muris_, _S. bertrami_, _S. tenella_, and _S. colii_ can multiply by longitudinal fission. SARCOSPORIDIA OBSERVED IN MAN. (1) Lindemann[233] found on the valves and in the myocardium of a person who had died of dropsy certain brownish masses, 3 mm. in length and 1·5 mm. in breadth which he regarded as gregarines. If these were actually independent animal organisms it may be suggested that they were Sarcosporidia. Rivolta (1878) named the species _S. lindemanni_. [233] “Ueb. d. hyg. Bdtg. d. Gregarinen,” _Dtsche. Ztschr. f. Staatsarzneikunde_, 1868, xxvi, p. 326. (2) Rosenberg[234] found a cyst 5 mm. in length and 2 mm. in breadth in a papillary muscle of the mitral valve of a woman, aged 40, who had died from pleuritis and endocarditis. The cyst contained no scolex nor hooklets of tænia. Numerous small refracting bodies, round, oval or kidney-shaped, were found in a daughter cyst, as well as sickle-shaped bodies. The description hardly appears to indicate Sarcosporidia. [234] “Ein Befund von Psorosp. in Herzmusk d. Menschen,” _Ztschr. f. Hygiene_, 1892, xi, p. 435. (3) Kartulis[235] observed Miescher’s cylinders of various sizes in the liver (?) and in the muscular system, of a Sudanese who had succumbed to multiple abscesses of the liver and abdominal muscles. This may be considered as the first actual case of the occurrence of Sarcosporidia in man. Koch in 1887 described a case in Egypt. [235] Kartulis, “Ueb. pathog. Protoz. b. Menschen,” _Ztschr. f. Hyg. u. Inf._, 1893, xiii, p. 1. Compare also Braun, M., _Die Thier. Par. d. Mensch._, 2nd Edit., Wrzbg., 1895, p. 92; Braun, M., “Z. Vork. d. Sarcosp., b. Menschen,” _Centralbl. f. Bakt._ 1895, xviii, p. 13.