ABSTRACT
The annelid body, as typified by that of Nereis, consists of a presegmental prostomium, a number of segments, and a postsegmental pygidium. The larval trochosphere is unsegmented. Once proliferation of segments has started, their number increases steadily throughout most of the life of the adrenal, though the rate of proliferation declines (Clark & Clark, 1962). New segments are added posteriorly by proliferation and differentiation of tissue comprising the growth zone, which forms the anterior border of the pygidium. After loss of the pygidium and posterior segments, wound healing is followed by the formation of a new growth zone. Amoebocyte migration (Stephan-Dubois, 1955,1956,1958) and dedifferentiation of cells adjacent to the level of transection (Herlant-Meewis & Nokin, 1962) are important in the early stages of regeneration. Proliferation of segments recommences and they are produced more rapidly than they are in the intact animal, as will be shown later.
