Fig. 9

Growth of the late mitraria larvae. CLSM images of EdU and phosphoHistone 3 (PHH3) labeling on mitraria larvae from a, e 1 wpf to d 4 wpf. Images in a–d are ventral views with anterior facing up, while those in e–g are lateral views with anterior facing left. eʹ–gʹ Are close-up sections of (e–g). a–g Proliferation in the late mitraria continues mostly in the ciliary bands, the gut and the developing juvenile rudiment. Open arrowheads point to the flexions of the ciliary band. eʹ–gʹ The juvenile rudiment has proliferative cells and a terminal mitotic cell, in what it could represent a posterior growth zone. an: anus; ao: apical organ; bp: blastopore; cs: chaetal sac; fg: foregut; hg: hindgut; jr: juvenile rudiment; la: lappet; mg: midgut; mo: mouth; mt: metatroch; nt: neurotroch; pt: prototroch. Scale bar is 50 µm. In eʹ–gʹ the scale bar is 25 µm