46 FRESHWATER RHIZOPODS OE NORTH AMERICA. 



The food of Amaiba villosa and other Rhizopods appears always to be 

 swallowed together with some water, which subsequently is commonly 

 observed as a clear area surrounding the food within the endosarc. Soft 

 food, vegetal and animal, assumes the form of spherical balls; but more 

 consistent food, such as diatoms, retains the original form according to its 

 degree of resistance. The distinctive character of soft articles of food 

 rapidly disapjDears after being swallowed. The different food materials 

 undergo chemical changes as a result of digestion in the endosarc, and 

 colors become changed in a striking manner. The bright-green chlorophyl 

 of alga? becomes brown or yellow and shriveled within the colorless cells, 

 and the endochrome of diatoms becomes browner in hue and shriveled into 

 two narrow strings within each shell. 



Some ooze gathered in the month of September from a mill-pond, in 

 which grows a profusion of the magnificent Nelumbo, Nelwmbium luteum, 

 near Woodstown, New Jersey, contained many large specimens of Amoeba 

 proteas, like the one represented in fig. 7, pi. I. This individual occupied 

 a space of about one fourth of a line in length by one sixth of a line wide 

 in front, where three large finger-like pseudopods diverged. The nucleus, 

 if present, escaped my notice. The contractile vesicle usually occupied 

 a position at the posterior extremity. The endosarc contained numerous 

 large, round or oval, yellowish, granular balls, supposed to consist of food, 

 but not visibly included in water-drops. Many of these were darkly out- 

 lined, and appeared to have an oil-like consistence. With them were also 

 mingled many clear colorless globules, granules, and crystals. When the 

 specimen was first noticed, it contained, just in advance of the position of 

 the contractile vesicle, a Brachionus, which finally assumed the appear- 

 ance of an ordinary food-ball, resembling the abundance of yellowish balls 

 with which it was associated. 



In movement, the main trunk and larger pseudopods of the same 

 Amoeba assumed more or less the appearance of being longitudinally folded. 

 The endosarc axially flowed as if in the interior of thick walled canals, of 

 which the walls appeared to be composed of finer granular matter with 

 scattered imbedded crystals. In the flow, all the contents did not move 

 with the same rapidity, and usually the smaller particles were swept quickly 

 by the larger ones. Other matters, including some of the largest elements, 

 appeared to stick to the inner surface of the extemporaneous tubes, but 



