PLATE VIII. 



Figs. 1-16.— AMffiBA VILLOSA 



Figs. 1-3. Small individuals, from water of a sph» gnons swamp on Broad Mountain, Soliuylkill 

 County, Pennsylvania; collected September, 1876. 200 diameters. Figs. 1, 2, two views of the same 

 individual. Fig. 3. Another individual in which the miclous appears more distinctly discoidal. 



Figs. 4-16. Supposed young of Ammla villoaa. In water from a brick-pond near Swarthmore 

 College, Delaware County, Pennsylvania, kept during the winter, and examined February, 1875. Figs. 

 4-8, 500 diameters. 



Fig. 4. An individual dragging after it a large spherical alga. Within, it exhibits the nucleus In 

 advance of the position of the contractile vesicle. 



Fig. 5. Another individual, with two contractile vesicles, and the nucleus posteriorly situated. 



Fig. 6. An individual with the contractile vesicle in the act of collapse. 



Fig. 7. Another individual with large contractile vesicle and in advance a small nucleus. Fig. 8 

 is an outline of the same individual as it first appeared. 



The green balls within the animals consist of unicellular algse or spores which covered the surface 

 of the water containing the Amasba. The red balls appear to be the same kind of algse changed in 

 color by digestion. Among the contents numerous minute crystals are observed. 



Fig. 9 n-e. Some of the crystals magnified 1,200 diameters. 



Fig. 10. An individual, magnified 750 diameters, exhibiting a multitude of crystals among its 

 contents. The nucleus occupies a position just posterior to the contractile vesicle. 



Fig. 10 a. A crystal magnified 1,200 diameters. 



Fig. 11. An individual which, after moving about for some time, with the form seen in the pre- 

 ceding figures, spread out in disk-like shape and became very thin. The nucleus to the left, with a 

 reddened algous spore resting against it. 700 diameters. 



Fig. 12. A resting individual containing u, large nucleus with coarse uniform granules. 700 

 diameters. 



Figs. 13, 14. Two views of an individual containing two large and coarsely granular nuclei. 

 Fig. 14 exhibits the mutual compressibility of the nuclei and contractile vesicle, as seen in the move- 

 ments of the animal. 500 diameters. 



Fig. 15. An individual as it appeared at the moment of collapse of the contractile vesicle and 

 the bursting of one of the nuclei with the simultaneous escape of the granules or spores of the nucleus 

 and the contents of the contractile vesicle. Tlio red bodies are algous cells. 533 diameters. 



Fig. 16. An individual containing six large granular nuclei, which, together with the equally 

 large contractile vesicle, rolled about among one another in the movements of the animal. 500 diame- 

 ters. 



Pigs. 17-30.— Supposed young of AMCEBA PEOTEUS. 



Figs. 17-20. Four individuals, from among a multitude contained in water with Nitella, fur- 

 nished by Mr. Holman in one of his "life-slides," January 8, 1875. The nucleus of variable size. 1,000 

 diameters. 



Figs. 21, 23. Two views of an individual. Fig. 23. A second individual. Obtained, together with 

 many others of the same kind, in water from a cow-track in a springy x)lace on Darby Creek, Delaw.are 

 County, Pennsylvania, March, 1876. 500 diameters. 



Figs. 24-26. Three individuals, observed with m.any others together with large characteristic 

 specimens of Amoeba proteus. From ditch-water, collected in the meadows below Philadelphia, April, 

 1874. 500 diameters. 



Figs. 27, 28. Two different individuals, observed in association with the preceding, containing a 

 large tripartite nucleus. Others were observed with the nucleus simple and in various stages of tripar- 

 tite division. 500 diameters. 



Fig. 29. Individual found in association with those of figs. 21-23, together with others of inter- 

 mediate size. Observed in the act of discharging two diatoms, while nothing else was seen to escape. 

 .Fig. 30. An individual, observed in the act of division. Separation occurried in ten minutes 

 after having noticed the animal as seen in the figure. Subsequently the lower individual escaped, 

 while the upper one was watched and was seen to divide in the same manner as its parent, hut in a 

 direction at right angles to the former one. The offspring assumed a slug-like shape as in figs. 4, 10, 

 20, 29, and moved away. 500 diameters. The two largest globules to the left in each figure, inadvert- 

 ently colored by tjie lithographer, were colorless and oil-like. 



Fig. 31. PELOMYXA VILLOSA. An individual which was retained over night in abundance of 

 clear water in an animalcula cage without pressure. It remained nearly motionless, but occasionally 

 protruded a clear lobular portion of ectosaro together with a few pointed pseudopods and shifted its 

 position. The posterior part of the body was minutely papillate. Slight pressure caused the sudden 

 discharge through- a rupture of the ectosarc of some of the contents, consisting of clear globules, 

 granules, a few large nuclei, and numerous linear particles, together with food-materials. From Abse- 

 com pond. New Jersey, August, 1874. 100 diameters. 



Fig. 32. One of the discharged nuclei, with coarse unifoim gr.anules superficially imbedded. 

 1,000 diameters. 



Fig. 33. Granules and linear particles from the same. 1,000 diameters. 



Fig. 34 a-l. Concretionaiy mineral elements observed in some Amoebas, of the kind represented 

 in figs. 4-lG, aud found in association wi(h them, Febrnai-}-, 1875. 4,000 diaUioters. 



