Trypanosoma duttoni exhibits the typical trypanosome morphology in that it is bounded by a unit membrane which included its anterior flagellum; it is surrounded by a framework of suppellicular fibrils, and it contains a nucleus and the posteriorly located kinetoplast-blepharoplast structures along with cytoplasmic organelles (mitochondria, Golgi, and enoplasmic reticulum). Very prominently displayed in T. duttoni is the contractile vacuole, which has not previously received wide-spread recognition. The kinetoplast is clearly continuous with mitochondria in some cases. Inclusion bodies are categorized into three distinct types, none of which can be conclusively designated as the very popular volutin granules, without cytochemical evidence. The existence of a third tubule among peripheral tubule doublets of the flagellum is observed.