3. In H. townsoni male sterility is associated with a timing disturbance which causes a chimerical arrangement of division stages within loculi, and also with a frequent failure of pairing of one bivalent. A causal relationship cannot be ascertained. The three phenomena may indicate a major physiological disturbance. 4. Male sterility has mainly been ascertained under experimental conditions, especially after induced self-fertilisation. Under conditions of relative isolation, which favours its occurrence, male sterility serves as a mechanism for reducing self-fertilisation. 5. In gynodiœcious species, the production of “female” plants may often, originally, be determined by single genes for pollen sterility. Published in Journal of Genetics, Vol. XL, Nos. 1 and 2, pp. 171–184, May, 1940. Description of a New Intestinal Protozoan from a Gecko. E. Percival. Trichomonas n.sp. was described from the rectum of Hoplodactylus sp. collected on the Cass River bed. Its characteristic features were given and a comparison made with other Triehomonads from Reptilia. The Early Development and Metamorphosis of a Brachiopod. (An Addition to the Life History of Terebratella inconspicua.) E. Percival. The unfertilised and the fertilised egg were described. Development was followed through segmentation of the egg, gastrulation, the transformation of the gastrula into the free-swimming larva, the attachment of the larva to the substratum, and the metamorphosis of the newly attached larva to form the bivalved young brachiopod. Only the external features of this development were described and figured, the internal changes being left for later consideration. Observations on Huberia striata Smith and Discothyrea antarctica Emery. W. E. Moore. H. striata, an abundant ant in uncultivated areas, lives in populous but un-coördinated communities extending over an area of hundreds of square yards, and does not fight with strange ants of its own species. New colonies are normally formed by branch nests. The little Discothyrea antarctica lives as a tolerated inquiline in nests of this species. In a colony under observation, the Discothyrea spent most of their time in the Huberia brood nest, and though sometimes threatened, were never injured.