Fig. 106.—Young Sarcocystis tenella of the sheep, 47 µ in length. (After Bertram.)
Fig. 107.—End of a trophozoite of Sarcocystis miescheriana from the diaphragm of the pig, showing division in pansporoblasts. × 800. (After Bertram.)
Fig. 108.—Sarcocystis blanchardi of the ox. Longitudinal section of sarcocyst or Miescher’s tube. a, substance of muscle fibre; b, envelope of sarcocyst; c, muscle nuclei; d, spores in chambers; e, ground substance. × 400. (From Wasielewski, after van Eecke.)
The spores (sometimes called Rainey’s corpuscles), vary in shape according to the species, but are also of different form individually. They are mostly kidney-, bean- or sickle-shaped (fig. 109), and of small size, sometimes reaching 14 µ by 3 µ to 5 µ. They are apparently surrounded by a thin membrane, and at one extremity (according to the discovery of L. Pfeiffer, confirmed by van Eecke, Laveran and Mesnil) contain an obliquely striated body (fig. 109) often homologized with the polar capsule, while the greater part of the spore is taken up by the nucleate sporozoite. Several authors state that they have also observed filamentous appendages (polar filaments) at one end of the spores, and have seen two kinds of spores in the same Sarcosporidium. Spores of various species of Sarcosporidia may contain metachromatic granules, often centrally placed (fig. 109). These granules may be metabolic or possibly may contain toxin (see below).