Observations on the morphology and sporogony of a coccidianAdelina rayi n. sp. from the gut of the centipede,Rhysida longipes

Abstract

The morphology and sporogony of a coccidian,Adelina rayi n. sp. from the gut of the centipede,Rhysida longipes are described. Two types of schizogony have been observed. The macroschizonts which develop just below the basement membrane and beyond the level of nuclei of the midgut epithelium grow to a maximum size of 25·0–30·0×20·0–25·0µm and produce 80–100 merozoites. Each macromerozoite measures 12·0–13·0×1·57–2·0µm with a centrally placed nucleus. The nucleus is surrounded by a delicate nuclear membrane and has numerous small chromatin granules attached to the inner wall in addition to a single slightly larger chromatin granule placed in the centre. The microschizont reaches a maximum size of 13·0–15·0×7·0–8·0µm and produces 16 merozoites. It develops in the midgut epithelium below the level of the host cell nuclei. Each micromerozoite measures 9·6–10·6 × 1·5–2·0µm. The nucleus is centrally placed and is surrounded by a delicate nuclear membrane. The chromatin is in the form of numerous granules attached to the inner wall. No centrally placed chromatin granule in the nucleus has been observed. Association between the gametocytes occurs in the nucleus stage. The macrogametocyte reaches a maximum size of 18·0×15·0µm and the microgametocyte a maximum of 15·0×4·0µm. The microgametocyte gives rise to 4 deeply stained comma-shaped microgamates. Oocysts measure 20·0–22·0×18·0–20·0µm. They are octosporous and dizoic. The sporozoites measure 12·0–14·0×2·0–2·5µm.