[Ultrastructure of the cyst wall of sarcocysts of the roe deer (Capreolus capreolus L.) (author's transl)].

The ultrastructure of the cyst wall of two types of sarcocysts from roe deer is described. In the thin-walled cyst (wall thickness 0.18-00.26 micrometer), the primary cyst wall forms long, finger-shaped protrusions distant from one another and running in parallel with the surface of the cyst (Figs. 1a--d, FP). No fibrils are observable in the protrusions. The primary cyst wall between them forms numerous bubble-like invaginations (Fig. 1c, arrows). In the thick-walled cysts (wall thickness 4.9--7.49 micrometer), the primary cyst wall forms massive, palisade-like protrusions lying close one to another (Figs. 2a, c). There are numerous fibrillar and tubular structures in these protrusions (Fig. 2d), and the primary cyst wall occasionally forms shallow invaginations at the base of some protrusions (Fig. 2b). The unit membrane onthe surface of some protrusions is slightly undulated and covered with a layer of short and thick bars on the outside. The sarcocysts found in roe deer are compared with those from cattle and sheep.