Multiplication took place by means of division and budding (fig. 15, _c_), after previous direct division of the nucleus. The buds were supposed to divide repeatedly soon after their appearance, thus giving rise to minute forms of 3 µ. There was a suspicion in both cases that the ascites was associated with malignant neoplasms in the abdomen, and autopsy confirmed this view in one case. [Illustration: FIG. 15.--_Leydenia gemmipara_, Schaud. _a_, in a quiescent condition, × 1000; _b_, in the act of moving, × 1000; _c_, from a fixed preparation, showing a bud, × 1500.] The parasite, which has seldom been observed, has been variously interpreted; for example, it has been regarded merely as altered tissue cells. It is now known, from Schaudinn’s researches, that _Leydenia gemmipara_ is connected with abnormal conditions of _Chlamydophrys_, occasionally occurring as a commensal in the ascitic fluid. The form is produced when pathological conditions of the large intestine create an alkaline reaction of its whole contents. The formation of shells then often ceases, and these naked _Chlamydophrys_ are enabled to multiply atypically by division and gemmation. Such stages, which are no longer capable of a normal development, are the _Leydenia_, as Schaudinn has demonstrated. Class II. *MASTIGOPHORA*, Diesing. Sub-Class. FLAGELLATA, Cohn emend. Bütschli. During the motile part of their life the Flagellata possess one or more flagella which serve for locomotion, and in many cases also for the capture of food. A few groups (_Euglenoidinæ_, _Choanoflagellata_) have only one flagellum, others two or several of about equal length (_Isomastigoda_), or of various lengths (_Monadina_, _Heteromastigoda_, _Dinoflagellata_). The long flagellum is the principal one; the smaller ones on the same organism are accessory flagella. The flagella directed backwards, which occur in the Heteromastigoda and are used for clinging, are termed trailing flagella or tractella. At the base of the flagellum, which is almost always at the anterior end, a Choanoflagellate possesses a cytoplasmic funnel-shaped neck or collar. In the parasitic forms an undulating membrane is often present.