The regeneration of the anterior end of the earthworm has been carefully worked out by Hescheler, and although on account of the greater complexity of the process the results are not so decisive as those just described, yet in many respects they are in agreement. In Hescheler’s experiments only four or five anterior segments were cut off. The closing of the cut-end is somewhat different from that in lumbriculus. A plug of cells soon forms over the end (Fig. 58, _A_). The new cells appear to be lymph cells. Although this mass of cells may be quite large, the cells do not seem to form later any of the organs in the new head. The presence of these cells makes it very difficult to work out the origin of the other cells that appear later. Owing to the absence of this lymph plug in lumbriculus and nais it is easier to follow in them the regenerative processes. In the midst of these lymph cells spindle-like cells soon appear whose origin is obscure, but Hescheler thinks it improbable that they are transformed lymph cells, although they are completely intermixed with the latter. The spindle-cells arrange themselves later in regular bands, that appear to be extensions of the longitudinal muscles. A few days after the operation, the lymph plug is covered over, beginning at the edge, by the ectoderm. The new ectodermal cells arise from the old ectoderm, and seem to extend over the lymph plug by a sort of migration process. Division of the cells does not occur at this time. These covering cells are at first all alike, the characteristic gland cells of the ectoderm being absent. The digestive tract withdraws somewhat from the outer cut-surface, and its end closes. The closed end abuts against the inner surface of the lymph plug. The next changes are initiated by the appearance of karyokinetic divisions in all the tissues of the new part, which lead to a rapid growth and elongation. Dividing cells are found in the new, as well as at the border of the old, ectoderm, where the new and the old parts are continuous. At this stage there appears in the lymph plug another kind of cell, that seems to arise, in part at least, from the ectoderm by an in-wandering of new cells. Other new cells may come from the edge of the old muscles, but it is not clear whether they come from a transformation of muscle cells, or from undifferentiated cells lying in the old muscles. In addition to these sources of new cells, it appears not improbable that cells may separate from the end of the digestive tract.