In 1994, fresh fecal samples were collected and examined for coccidian parasites from 43 spiny mice (Acomys cahirinus) and from 60 wood mice (Apodemus mystacinus). The 2 genera of rodents inhabit an area in Lower Nahal Oren, Mount Carmel, Israel, known as Evolution Canyon, which consists of opposite-facing slopes that are geologically identical, but micro-climatically very different. Acomys cahirinus is found primarily on the warmer and drier south-facing slope (SFS), whereas A. mystacinus primarily inhabits the cooler and wetter north-facing slope (NFS). None of the samples from the A. mystacinus contained coccidia, but 6 of 43 (14%) A. cahirinus individuals were discharging eimerian oocysts that we describe herein as a new species. Five of the 6 positive samples were from the SFS. Sporulated oocysts are ovoidal to subspheroidal, 26.5 × 22.9 (21-29 × 19-26) μm, without a micropyle, but with an oocyst residuum of 1 to several large clear globules and a medium-sized refractile polar body; they contain lemon-shaped sporocysts, 10.4 × 8.1 (10-11 × 7-10) μm, with a sporocyst residuum and Stieda body, but no sub-/or parastieda body. Sporozoites lie side by side, completely filling oocysts; each contains a large posterior refractile body
