Fig. 6

The early juvenile of Lineus ruber. A–E z projections of confocal scans of juveniles labeled against F-actin (gray) counterstained with the nuclear marker Sytox Green (yellow) 25 days after oviposition (dao). A Juveniles with a large volume of ingested yolk keep a spherical shape, although they exhibit mature tissues. B The adelphophagy of the Schmidt’s larva not only affects unviable embryos, but also developing siblings. C–E Juveniles with a moderate quantity of yolk soon adopt a worm-like shape. The body wall musculature is well developed and the head region has a muscular mouth (D′), and a central rhynchocoel with the two brain lobes at each side (D′′–D′′′). Posterior to the brain, the ectoderm on the left and right sides of the head invaginates and forms the cerebral organ canal (D′′′, E), the connection of the cephalic organ with the exterior. Note in (E) the particular ciliation of the inner canal compared with the outer epidermis. A A lateral view, with the dorsal side to the top. B–E Are ventral views. In all panels, anterior is to the left. bl brain lobes, coc cerebral organ canal, iy ingested yolk, le larval epidermis, mo mouth, pb proboscis. Scale bars (A–D′′′) 100 μm; (E) 25 μm