Morphological characteristics of Sarcocystis arieticanis sarcocysts from sheep muscle. (A) Light micrograph of a sarcocyst (unstained); note the sarcocyst wall with numerous hair-like protrusions (hp). Scale bar = 20 μm. (B) Transmission electron micrograph of the cyst wall of a sarcocyst; note host cell (hc), bradyzoites (bz), and hair-like protrusions (arrow). Scale bar = 1 μm.