Dr. Murai Éva szerk.: Parasitologia Hungarica 16. (Budapest, 1983)

Cysts located in the muscle cells of the heart were limited by a primary cyst wall of 15-20_um in thickness (Figs 1,2,4). This wall was thrown in band-like protrusions of 0.5-3jum in length and 0.02 ^um in width. The band-like protrusions sometimes were arranged in staples (Fig. 2) measuring 0.2 urn in thickness. At the base of the protrusions the primary cyst wall formed bubble-like regularly distributed elevations (Fig. 2). Underneath the primary cyst wall an electron-lucent granular material, the so-called groundsubstance, formed a band of 0.2-0. 26 ,um in width and gave rise to very small septa which divided the cyst into compartments. The compartments were tightly packed with merozoites and a few metrocytes (Figs 1,2). Merozoites (cystozoites) and metrocytes The banana-shaped merozoites (cystozoites) measured 9-11. 8 jum in length and 2. 2-2. 7 ^m in width. They contained a large number of micronemes and several rhoptries in their anterior part. A prominent nucelus with numerous electron-dense plaques, a mitochondrion, amylopectin granules and rough endoplasmic reticulum were found in the posterior part of the merozoites (Fig. 3). Polymorphous metrocytes were mostly located at the peripheral part of the cyst and measured 3.4-7.9 urn in diameter (Fig. 4). Merozoites and metrocytes were limited by a three membranous pellicle. A characteristic finding inside the cyst was the accumulations of globular amorphous material and the membranes of 2. 0-3. 2 jum in diameter having the appearance of degenerated merozoites. These structures were present in most of the cysts examined (Fig.l) DISCUSSION It is difficult to determine who first described a Sarcocystis species from Cervus elaphus. The literature gives different answers to this question (BABUDIERI, 1932; KALYAKIN and ZASHUKHIN, 1975; LEVINE and TADROS, 1980) and mostly refers to S. gracilis. This Sarco cystis species, however, is a parasite of the roe deer Capreolus capreolus (RÄTZ, 1909; ERBER et al. , 1978; ENTZEROTH, 1982). The first report of SarcocyBtis infection in Cervus elaphus was made by JONGH in 1886. The first name, Sarcocystis grüneri, was given for a Sarcocystis species found in the Maral (Cervus canadensis asiaticus Erxleb.) by YAKIMOFF and SOKOLOFF (1934). This red deer species today is considered to belong to the species Cervus elaphus (Mc CULLOUGH, 1959; HALL, 1981). The authors YAKIMOFF and SOKOLOFF (1934), however, used the name S. grüneri also for a Sarcocystis species of the reindeer (Rangifer tarandus). In the year 1978 the first study of the life cycle of Sarcocystis of Cervus elaphus was done in Spain by NAVARRE TE et al. who found that the dog (Canis familiáris) is the final host. The name Sarcocystis cervicanis was given for this species by HERNANDEZ RODRIGUEZ et al. in 1981a. Studies on Sarcocystis of Cervus elaphus in Byelorussia by LITVINOV (1982) also revealed the dog as final host. A recent study of Sarcocystis of the Maral (Cervus elaphus sibiricus; the author POLOMOSHNOV (1982) named the Maral as "Cervus elaphus sibiricus") reports that the wolf sheds Sarcocystis sporocysts after a prépaient period of '7-8 days p. i. and considered this species as Sarcocystis grüneri (POLOMOSHNOV, 1982). So it is evident that S. grüneri (YAKIMOFF and SOKOLOFF, 1934), S. cervicanis (HERNANDEZ RODRIGUEZ et al.

, 1981a) and S. wapiti (SPEER and DUBEY. 1982) are synonyms. However, S. grüneri has priority. It also needs to be clarified what relation exists between S. grüneri and the Sarcocystis sp. in the American wapiti. (Cervus elaphus canadensis) studied to find out by MARGOLIN and JOLLY (1979) and DUBEY (1980). Further studies are needed whether there are more than ond S. species parasitizing C. elaphus as reported e.g. from the roe deer Capreolus capreolus (Erber et al., 1978). The ultrastructure of the cyst of Sarcocystis studied in this paper