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University of California Puhlications in Zoology [Vol. 20 



its whole length in five seconds. There are frequent changes in direc- 

 tion of locomotion, due either to the swerving of the pseudopodium 

 as a whole or to the origin of pseudopodia at new areas on the per- 

 iphery. The nucleus generally lags in the posterior part of the body 

 when the same general direction is maintained continuously for a 

 time. The pseudopodia lie at or near the level of the substrate. 



Fig. A. Free-hand sketches of nine successive phases of formation of pseu- 

 dopodia in an active amoeboid stage of CouncUmania lafleuri during one minute. 

 X about 600. 



There is generally a single pseudopodium in formation at one time. 

 It is perfectly clear and appears to be composed wholly of ectoplasm. 

 It is usually broad, from one-fourth to one-half the diameter of the 

 body in width, though in elongated, traveling individuals it may rarely 

 equal the width. In rounded-up individuals a slender pseudopodium 

 one-fifth the diameter in width and as long as the radius may be 

 thrown out. The tip of the pseudopodium is broadly rounded, rarely 

 crenated or lobed, never pointed or bifurcated. In mobile individuals 

 the pseudopodium is quickly invaded by the gi'anular, vacuolated endo- 

 plasm. Pseudopodia may be found at two, rarely three, areas on the 



