Oocysts and sporocysts of Eimeria funduli sp. n. are described from the Gulf killifish, Fundulus grandis, on the basis of light microscopy, transmission and scanning electron microscopy, and location in the liver of infected hosts. The spherical sporu!ated oocysts of E. funduli isolated from liver tissue measure 20–31(25) ıtm across with ovoid sporocysts 9–11 × 5–7 (10 × 6) ıtm. A micropyle, polar granule, and oocyst residuum are absent, but sporocysts have Stieda and substieda bodies, a few residual granules, and 10–25 (15) unique projecting structures with expanded distal portions that we term “sporopodia”. Sporopodia 1–3 (2) ı high support a transparent membrane that completely surrounds the sporocyst. Sporozoites have one large posterior refracti!e body. U!trastructural!y, the oocyst wall consists of two thin layers of granular material: an electron-dense outer layer with a rough external surface and an electron-lucent inner one of approximately equal thickness. One or two unit membranes line the inner surface of the inner layer. Each layer is 40–60(55) nm thick. The sporocyst wall, 78–130 (110) nm thick, consists of an e!ectron-lucent material with the outer surface being more electron dense and giving rise to osmiophilic sporopodia; closely associated with these and the outer surface are one or two unit membranes. A thin osmiophi!ic layer of fine granular material lines the inner surface.
This study was conducted in cooperation with the U.S. Department of Commerce, NOAA, National Marine Fisheries Service, under PL 88-309, Project 2-325-R. It was also supported, in part, by a University of New Mexico Research Allocations Grant-in-Aid.