180 A Contribution to our Knowledge of the Protozoa of the Soil, 



9. Schewiakoff, W., " The Organisation and Systematic Arrangement of the Infusoria 

 asperotricha" (in Russian language), 'Mem. Acad. Sci., St. Petersburg,' 1896, 

 Series 8, vol. 4. 



10. Senn, G., article "Flagellata" in Engler and Prantl's ' Pflanzenfamilien,' Leipzig, 

 1900. 



EXPLANATION OF PLATE 4. 

 The figures were all drawn with the aid of the camera lucida. 



Fig. 1. — Cercomonas sp.? X1200. Stained with methyl green, showing the two flagella. 

 arising from the outer nuclear zone. 



Fig. 2. — Amoeba " Umax." x 3000. Stained Heidenhain's hsematoxylin. 



Fig. 3. — Chilodon sp. X 1200. Dorsal view, showing mega- and micro-nucleus. 



Fig. 4. — Colpoda cucullus. x 1000. From a living example. The round bodies are food 

 vacuoles ; one is in process of formation at the mouth. 



Fig. 5. — Colpoda cucullus. X 610. An example developing within the endocyst. Nuclear 

 area shown as a dense circular area. Mass of excretion matter also present. 



Fig. 6. — Colpoda steinii. x 1200. Stained with methyl green, showing mega- and micro- 

 nucleus. 



Fig. 7. — Balantiophorus elongatus. x 1200. Lateral view, stained methyl green, mega- and 



micro-nucleus showing. 

 Fig. 8. — Pleurotricha grandis ? x 610. Ventral view. 

 Fig. 9. — Gonostomum affine. x 760. Ventral view. 



Fig. 10. — Vorticella microstoma. x610. From a living example of the stalked form. 

 Fig. 11. — Vorticella microstoma. x760. The free-swimming, recently excysted form with 

 aboral ciliary ring. 



