This nonmotile stage is infective whereas the motile embryonic stage is not.
In 36 hours a motile, tadpole-like stage is reached and in a few days the embryo becomes quiescent and nonmotile.
"capable of movement," 1831, back-formation from motility.
motile mo·tile (mōt'l, mō'tīl')adj.
Moving or having the power to move spontaneously.
Of or relating to mental imagery that arises primarily from sensations of bodily movement and position rather than from visual or auditory sensations.