PLATE XXXIII. 



Figs. 1-9.— PAMPHAGUS MUTABILIS. Transverse diameters unequal. 



Fig. 1. Animal viewed iu the upright position partially twisted on itself. 500 diameters. Spring 

 on Darby Creek, Delaware County, Pennsylvania, August, 1874. 



Fig. '2. The same individual seen from above. 



Fig. 3. Broad side view of an individual. Same locality as the former. 



Fig. 4. Narrower side view of the same, bent so as to be concave on the right. 



Fig. 5'. Broader side view of an individual. Fig. 6. Inferior view of same. 500 diameters. 

 Same locality, April, 1875. 



Fig. 7. Broader side view of an individual. Kirkwood mill-pond, New Jersey, September, 1874. 

 1,000 diameters. 



Fig. 8. Broader side view of an individual. 500 diameters. Darby spring, Pennsylvania, Au- 

 gust, 1874. 



Fig. 9. Broader side view of an individual. 500 diameters. Sphagnum, Atco, N. J., May, 1877. 



Fig. 10.— PAMPHAGUS AVIDUS. Transverse diameters equal. 



Upright view ; the. mouth to the right interiorly, and emitting pseudopods. The animal stretched 

 iu length out of its normal condition, by portions of the alga Didymoprium. "250 diameters. Atco, N. 

 J., September, 1877. 



Figs. 11, 12.— PAMPHAGUS CURVUS. Transverse diameters uniform. 



Fig. 11. Lateral view of an individual. Spring on Darby Creek, Delaware County, Pennsylvania, 

 August, 1874. 5C0 diameters. 



Fig. 12. Lateral view of an individual. Swarthmore brick-pond, Delaware County, Pennsylva- 

 nia, September, 1874. 



Figs. 13-17.— PAMPHAGUS HYALINUS. Spheroidal. 



Figs. 13, 14. — Upper and lateral views of the same individual, with protruded pseudopods. 500 

 diameters. Spring, Darby, Delaware County, Pennsylvania, April, 1875. 



Fig. 15. Lateral view of an individual, with pseudopodal extensions. 750 diameters. Fort 

 Bridger, Wyoming, July, 1877. 



Figs. Hi, 17. Lateral views of specimens with extensive protrusion of the Barcode. These were 

 suspected to be individuals in the process of multiplication by division, but they died under observation 

 iu the condition as represented. Found with the preceding. 



Figs. 18-28.— PSEUDODIFFLUGIA GRACILIS. 



Fig. 18. Lateral view of an ovoidal form, with shell apparently of chitinoid membrane and lino 

 granular dirt. 250 diameters. Egg Harbor, N. J., April, 1878. 



Fig. 19. Large .specimen of the same character. From the same gathering. 250 diameters. 



Fig. 20. Individual of same character as preceding, with a profusion of pseudopodal exteusions. 

 500 diameters. Swarthmore brick-pond, Delaware County, Pennsylvania, June, 1874. 



Fig. 21. Individual with a brown shell of chitinoid membrane and line sand. Found with the 

 preceding. 



Fig. 22. Individual with an oblique mouth. With the preceding. 



Figs. 23, 24. Two views of the same individual, with a retort-like shell. Also with the preceding. 



Fig. 25. Individual, in which the chitinoid shell at both extremities is heavily loaded with sand. 

 700 diameters. Spring on Darby Creek, Delaware County, Pennsylvania. 



FlGS. 2(5, 27. Lateral and superior views of a compressed ovoidal specimen, with shell of sand. 

 166 diameters. Egg Harbor, >>\ J.. August, 1878. 



FlG. 28. Lateral view of a specimen, with shell composed of sand. 500 diameters. Swarthmore, 

 Delaware County. Pennsylvania. 



