In May 1912 when on the way with our Floating Laboratory to Rejaf, en route for the sleeping sickness district in what was formerly the Lado Enclave (now part of Mongalla Province), the late Colonel Mathias shot, near Renkwood station on the White Nile, two specimens of the Senegal or red-fronted gazelle—Gazella rufifrons. I found one of these animals, a female in good condition, heavily infected with sarcosporidiosis, the diaphragm, the intercosted muscles and those of the thigh being specially affected, though the striped muscle fibre everywhere contained cysts in varying numbers. In the light of the observations made by Probst and Francis (1910) the blood was carefully examined but no sarcosporidial spores were found in it nor were any blood parasites present.