The morphology and affinities of the Entozoa (Protozoa), Spirilla, Treponemata and Endophyta found in captive Heterocephalus glaber from Somaliland and Kenya are described and illustrated.
Physiological cannibalism by Balantidium sp. on Trichomonas muris, as a means of restoring its nucleoprotein removed by the rodent is described.
The possible evolution of some of the Entozoa and Endophyta from free life to parasitism in insects such as termites is considered. The change from the free-living habit to cold-blooded and hot-blooded animals would have involved great plasticity and adaptability on the part of the organisms concerned but might have led to their gradual establishment in hot-blooded vertebrates.