The flagellate to be described in this paper was found in the faeces of a native of the Bahamas who was admitted to the Seamen's Hospital, Albert Dock, in October, 1909. In the course of the examination of the perfectly fresh material it was noticed that numerous flagellates were swimming about. They were taken to be Trichomonas but on closer examination they were seen to differ markedly from these. In the character of their movements there was little to distinguish them from Trichomonas except that the undulating membrane so characteristic of this genus appeared to be absent. The body is pear shaped and there are three long flagella directed forwards from the blunt end of the body. By the lashing of these three flagella the animal is drawn along with the blunt end in advance and at the same time revolves upon its longitudinal axis. A very characteristic feature is the presence of a very large cytostome extending from the base of the three flagella towards the posterior end of the body for about one half to two thirds of its length. The movements of the animals were at first so violent that great difficulty was experienced in making out the details of the anatomy, but as the faeces cooled their activities began to abate. It was then seen that the flagella was as long or longer than the body and that the large cytostome was arranged in a slightly spiral manner: that is to say it did not run directly parallel to the longitudinal axis of the body.