Dr. Murai Éva szerk.: Parasitologia Hungarica 23. (Budapest, 1990)

and 0.08-0.15 mm in width". No other gross or microscopic descriptions of the cysts were given but measurements of "sporozoites" in Giemsa preparations were so unusually large that certainly they must have been cyst merozoites (9.6-15.2 x 5.6-7.2 /im, "but most frequently 14.4 x 6.4 iim"); the latter measurement is probably the mean. The cyst merozoites described here are slightly shorter and more slender. However, measurements were taken of formalin fixed cells and may have undergone shrinkage due to fixation. It is particularly significant at this point that MATCHULSKI (1947) isolated S. sibirica from Capreolus pygargus, the Siberian roe deer and not from Capreolus capreolus (LINNE, 1758), the European roe deer, as has been repeatedly reported (TADROS and LAARMAN 1982, LEVINE 1986). For many years C. pygargus has been considered a synonym for C. capreolus, largely based on the ability of these two groups to interbreed in captivity; they are, however, morphologically distinguishable from each other and geographically isolated in nature (HONACKI et al. 1982). More recent studies have shown that interbreeding is not absolute in that sterile males are produced and that there are significant differences in the karyotypes (von LEHMANN and SÄLGESSER 1986). Consequently some authorities now regard these two populations of deer as separate species (von LEHMANN and SÄLGESSER 1986). If C. pygargus is indeed a distinct species, then the assignment of S. sibirica as originating from C. capreolus (LEVINE 1986, DUBEY et al. 1989) will probably have to be reconsidered since that name is already occupied in C. pygargus. Though it is likely that the sarcocysts described here are, in fact, S. sibirica (Matchulski, 1947) , the presence of nearly identical cysts in C. capreolus (ENTZEROTH 1982) is a complicating factor. It is clear that further studies need to be done, including identification of the final hosts, with the purpose of correlating presently occupied species names with their corresponding cyst forms in the intermediate hosts. In addition, the demonstrated reliability of cross-transmission as a means of determining host specificity in related intermediate hosts that harbor morphologically similar or indistinguishable cysts (reviewed by POLI et al. 1988) appears to be the most promising route to the solution of this problem. ACKNOWLEDGEMENTS paper OÍ'MATCHU BEYER, Institute of Cytology, Leningrad for translating the original