Macrostomorpha taxonomy and phylogeny

The pigmentspherules composing the cup (eyes) are the smallest that I have studied. Stylet: This tubular structure presents the figure of a long funnel with a widened crenate base and a slightly expanded termination. The opening is terminal. This species possesses a unique sperm-cell. This singular cell measures 36 micro in length and is equipped with the characteristic pair of anterior setae, a very thin feeler, and a tail region which bears a pair of lateral undulating flanges, in which region the chromatin granules are located. Chromatin granules are usually located in the anterior region of the sperm cell in Macrostomum. The feeler is a highly vibratile process. p. 125