Type host: Sorex tenellus Merriam, 1895, Inyo shrew.

Type locality: NOTHR AMERICA: U.S.A., California, Mono County, 22.5 km N, 4 km W, Bridgeport.

Geographic distribution: NORTH AMERICA: California.

Description of oocyst: Oocyst shape: subspheroid; number of walls: only 1 obvious layer; wall thickness: 1.0; wall characteristics: smooth; L x W: 21.6 x 19.3 (19-24 x 17-23); L/W ratio: 1.1 (1.0-1.3); M: absent; OR: absent; PG: usually, 1-2, but occasionally up to 7 highly refractile fragments. Distinctive features of oocyst: highly refractile nature of PGs.

Description of sporocysts and sporozoites: Sporocyst shape: ovoid; L x W: 11.9 x 7.4 (10-14 x 6-9); L/W ratio: 1.6 (1.3-1.9); SB: present; SSB: present, slightly wider than SB; PSB: absent; SR: present; SR characteristics: dispersed granules; SP: appear to be highly granular, with a distinct RB at one end. Distinctive features of sporocyst: highly granular appearance of SP.

Prevalence: 1/2 (50%).

Sporulation: Exogenous. Oocysts sporulatd in 7-10 days in 2.5% (w/v) aqueous potassium dichromate solution at ~23º C.

Prepatent and patent periods: Unknown.

Site of infection: Unknown. Oocysts recovered from feces and intestinal contents.

Materials deposited: Skin, skull, skeleton and tissues of the symbiotype host are preserved in the Mammal Division of the MSA, UNM: MSB No. 53229 (NK 7991, female), S.B. George #1059, 13 August 1983. Photosyntypes in the USNPC No. 86350.

Remarks: This species most closely resembles Eimeri suncus Ahluwalia, Singh, Arora, Mandal and Sarkar, 1979 from the common hpouse shrew (Suncus murinus) from India, but differs by having larger oocysts (22 x 19 vs 20 x 15) and by the presence of a SSB, which E. suncus lacks.

References: Hertel and Duszynski (1987).