1. A list is given of protozoa previously described from termites of different countries, and now recorded from Australian termites.
2. Observations on division stages of Janicki's ‘stout form’ of Devescovina striata do not support his contention that the ‘stout form’ is a pre-division stage of the ‘slender form’.
3. A new species Spirotrichonympha grandis is described from Porotermes grandis Holmgr.
4. The protozoa of Stolotermes victoriensis Hill include a new genus, Spirotrichosoma, of which two species occur--Spirotrichosoma obtusa and Spirotrichosoma capitata.
5. A Trichomonad flagellate from Porotermes grandis, mentioned but not described by Kirby, has distinctive characters which mark it as a new species, Pseudotrypanosoma minimum.
6. A new genus Pseudodevescovina (Pseudodevescovina uniflagellata) is described from Calotermes insularis White.
7. Mastotermes darwiniensis Progg., the most primitive known termite, contains in addition to a ciliate, Nycto-therus termitis, large and unusual flagellates for which the genera Mixotricha (Mixotricha paradoxa) and Deltotrichonympha (Deltotrichonympha operculata) have been erected. The morphology and possible affinities of these forms are of great interest.
8. Observations made on the ‘centroblepharoplast’ of Spirotrichosoma obtusa tend to show that this organ is in this form primarily skeletal rather than neuromotor in function. Division stages show that in Spirotrichosoma obtusa the axial organ does not function as a centrosome, so that the term ‘centroblepharoplast’ is inexact for this form. An analogous skeletal or supporting structure is found in Deltotrichonympha.