To say that the particles carried by the surface layer bring up at the anterior ends of pseudopods or of the ameba when in clavate shape, admits of further qualification. The advancing edge is not a straight line but an arc, and the sides near the advancing edge are building at a slower rate than the extreme tip. The most rapid formation of ectoplasm is at that point of the ameba that is farthest ahead. At this point all the ectoplasm to be made is still to be made, but as one passes back along the side of the pseudopod more and more ectoplasm is encountered and less and less remains to be made. There is therefore a gradient in the rate and in the amount of ectoplasm formed as one passes back from the forward end of the longitudinal axis of the pseudopod along the side. This is especially the case with certain amebas like _Amoeba discoides_, _A. laureata_ and others in which the pseudopods are more nearly cylindrical. In such amebas as _A. proteus_ and _A. verrucosa_, the factor of ridge formation complicates to some extent the longitudinal gradient of ectoplasm formation. But in spite of these specific differences, the general statement still holds that the rate of ectoplasm formation at the extreme anterior end is higher than anywhere else in the ameba, and that the rate gradually falls to zero as the nearly straight and parallel sides of the pseudopod or ameba, as the case may be, are approached. Now we have seen that if a particle becomes attached to the outer layer of such an ameba as discoides, which has nearly symmetrical pseudopods, at some considerable distance from the tip of the pseudopod, it moves forward until the tip of the pseudopod is reached. It does not tend to come to rest near the tip of the pseudopod, where the rate of ectoplasm formation is much higher than at the sides of the pseudopod, though not as high as at the tip, but it moves on until the tip is reached. That is, the movement of particles on the surface film is toward that small area at the extreme anterior end where the rate of ectoplasm formation is highest. In such an ameba as _verrucosa_, however, the highest rate of ectoplasm formation would be, not at a small circular area, but a very narrow strip along the anterior edge; for the rate of ectoplasm formation over a considerable portion of the width of the anterior end of the ameba is practically the same, according to observation. Consequently we do not find particles which are attached to the outer layer tending to move to a point lying on the longitudinal axis, but their paths are found to be straight and parallel with the longitudinal axis, if headed toward any point over a considerable stretch of the anterior edge on either side of the longitudinal axis. All the evidence that is at hand therefore points to the conclusion that the direction of movement of the surface film in a moving ameba is toward that point where ectoplasm is formed most rapidly.