FLATE XL 



ACTINOPHRYS SOL. 



*. ^. i. An individual feeding on green zoospores of an alga. Ditches below Philadelphia, among 

 Lemna, Wolffia, etc. May, 1874. 500 diameters. 



Figs. 2-4. Three views of the same individual, exhibiting the successive steps in the capture and 

 swallowing of a Euglenia. In fig. 3 the rays are left out, and in fig. 4 only partially given. Fair- 

 mount Park, June, 1874. 500 diameters. 



Fig. 5. Hcliozoon, supposed to be an A. sol. The nucleus distinctly visible ; large vacuoles at the 

 periphery ; and ouly about half a dozen rays. Fort Bridger, Wyoming, July, 1877. 



Fig. 6. Individual of uniform granular constitution, without vacuoles, and exhibiting a contrac- 

 tile vesicle at the boundary. Found with the preceding. 



Fig. 7. An individual, with even periphery, exhibiting a central nucleus, numerous vacuoles, and 

 a large colored food-ball. Besides the ordinary filamentous rays, it projected digitate pseudopodal pro- 

 cesses of protoplasm. 



Fig. 8. Another individual apparently ready to undergo division. It contains a number of colored 

 food-balls. With the preceding. Fort Bridger, Wyoming, August, 1877. 500 diameters. 



Fig. 9. Large individual, of finely granular constitution, with visible central nucleus, and large 

 peripheral vacuoles (the latter inadvertently left unshaded). Bristol Canal, Pennsylvania, with Cerato- 

 phyllum. August, 187f>. 500 diameters. 



Fig. 10. A pair in conjugation. The contractile vesicles seen above, a, discharge of an effete 

 ball. Swarthmore brick-pond, Delaware County, Pennsylvania, May, 1875. 500 diameters. 



Figs. 11-22. A pair of individuals, exhibiting the successive changes iu division. Some of the 

 figures are given merely in outline, and in a number the rays are not drawn. 350 diameters. 



Fig. 11. The pair as first noticed, with a large granular ball between them ; fig. 12, as seen three 

 hours subsequently ; fig. 13, two hours later ; figs. 14-16, successive changes during the next hour, when 

 separation oecurred as in fig. 17. Figs. 18, 19, successive changes of the left-hand individual leading to 

 separation into a pair. Figs. 20-22, successive changes of the right-hand individual leading to separation. 



