Eimeria urosauris n. sp., a Coccidium from the Lizard Urosaurus graciosus Hollowell, in California

SYNOPSIS. A new species of coccidium is described: Eimeria urosauris n. sp., in the gall bladder of the lizard Urosaurus graciosus Hollowell, from the Mojave Desert in California. The oocyst of E. urosauris is smooth, bilaminar, nearly cylindrical, with long borders only slightly convex, ends rounded and very nearly hemispherical. It is usually 32 × 20 μ, and its length/width ratio is 1.6. It contains 4 ellipsoid sporocysts, each 10.5 × 9 μ, for which 1/w is 1.17. Each sporocyst contains 2 tapered bent sporozoites with rounded ends, 11 μ long, 4 μ in diameter at the larger end, and 1.5 μ in diameter at the smaller end. Each sporocyst also contains a central granular sporocyst residuum 3.5 μ in diameter. The oocyst lacks a micropyle and oocyst residuum, and there is no Stieda body on the sporocyst. Sporulation time is 6–10 hr. Endogenous development, with reinfection by liberated sporozoites, occurs in the epithelial lining of the gall bladder. E. urosauris is compared to other morphologically similar lacertilian eimerias with which it might be confused.