Plate I

Fig. 1.—Glaucoma kirki: Live specimen drawn from the right dorsal aspect. The cytostome and cytopharynx are seen by transparency.

Fig. 2.—Glaucoma kirki: Oblique longitudinal section through the cytopharyngeal membranelles. Iron haematoxylin, 7 mu.

Fig. 3.—Glaucoma kirki: Transverse section through the inner portion of the cytopharynx and the macronucleus.

Fig. 4.—Glaucoma kirki: Transverse section, nearer the cytostome than that shown in Fig. 3.

Fig. 5.—Glaucoma kirki: Diagram of the ingestive apparatus.

Fig. 6.—Glaucoma kirki: Details of the anterior portion of the body; 10 per cent. nigrosin solution.

Fig. 7.—Uroleptus setiformis: Live specimen, from the ventral aspect.

Fig. 8.—Stentor loricata: Whole mount, showing the relationships of the cytopharynx, disc myonemes, and pigmented areas. Ehrlich's haematoxylin and easin.