[The morphology of the macrogametes and oocysts of Alveocystis intestinalis (Sporozoa: Coccidia)].

Macrogametes and oocysts of the coccidium Alveocystis intestinalis parasitizing in priapulids have been examined. It is shown, that the macrogametes of this species have small granules of glycoproteinaceous nature. These granules are wall-forming bodies. It was considered these bodies are absent in A. intestinalis. The oocysts in the investigated material contained mainly 4 sporozoites. The oocysts with 8 sporozoites, which were observed to be most frequent in the materials used for the original description of A. intestinalis, is not a standard for this species. Therefore the joining of A. intestinalis and Pfeifferinella gugleri into one genus based on a similarity of their oocyst structure is incorrect. This conclusion is also supported by the long evolutionary and ecological distances between hosts of these species.