100 PROFESSOR O. BUTSCHLI. 



movement has become more energetic, the organism increases 

 in length, and the flagellum is distinctly seen at one end. 

 No observations have been made as to the reproduction or 

 encystation of this interesting form. 



2. Rhizopoda possessing flagella.— Such organisms 

 have been described by Claparede and Lachmann^ under the 

 name Podostoma jiligerum, by F. E. Schulze^ as Mastigamoeha 

 aspera, and by Carter. The author has repeatedly found in 

 somewhat foul pond water, which has stood for a consider- 

 able time in a glass, an organism which is not identical 

 with any of the forms described. It has the appearance 

 of a small naked zhizopod, with delicate and somewhat 

 branched pseudopodia, which are not numerous (PL vi, fig. 

 25.) The shape is naturally very variable ; in a tolerably 

 elongated form the length is 0"02 mm. The protoplasm 

 appears to be very transparent, it is homogeneous, and it 

 never contains many particles. Usually there are a number 

 of constant vacuoles, some of which contain dark granules, 

 the ingested food materials, and moreover, minute dark 

 granules in large or smaller numbers. There is no 

 differentiation into Ecto and Entoplasm. The pseudopodia 

 are never very long, and are generally finely pointed -, 

 comparatively seldom they are branched so as to be 

 forked or antennate. A contractile vacuole, and sometimes 

 more than one, is present. The vesicular nucleus, with its 

 contained inner bodies, is clearly visible. In some specimens 

 it can be readily seen that the organisms possess a large 

 flagellum. Relatively, this flagellum is the largest observed 

 amongst the Flagellata, as it is sometimes eight or ten times 

 longer than the body. It is very delicate, and either vibrates 

 only at its outer extremity or lashes along its whole length. 

 The movements which the flagellum sometimes executes in 

 relation to the body are very peculiar. As the whole body 

 consists of movable amoeboid protoplasm, the place of in- 

 sertion of the flagellum is naturally variable, and the 

 flagellum is often seen slowly moving round the body, and 

 finally, returning to its original position. 



The movement is usually like that of a E-hizopod; some- 

 times the movements of the flagellum are energetic, and the 

 organism then begins to move like a Flagellate, by help of 

 its flagellum. In such a case the organism always assumes 

 an elongated shape (fig. 25 h), and the flagellum is 



* ' Etudes sur les Infusoires,' i, p. 441, pi. xxi', figs. 4 — 6. 

 2 'Arch. f. Mikr. Auat.,' £d. xi, p. 583. 



