Figure 2

Schematic diagrams and histological sections showing the gross anatomy of an eight-lobed larva and variation in ciliary band and ciliary tuft configurations (red) among polyclad larvae. (A, B) Maritigrella crozieri (2 days post hatching). (A) (i) Ventral view, (ii) frontal section; (B) (i) left lateral view, (ii) sagittal section. Masson’s trichrome stain, scale = 100 μm. (C-F) Ventral and left lateral views of Imogine mcgrathi (C), Stylochus ellipticus (D), Pseudoceros canadensis (E), Amakusaplana acroporae (F) larval stages, scale = 25 μm. (C) I. mcgrathi Götte’s larva with a continuous ciliary band anterior to the mouth, and separate ciliary bands on the ventro-lateral lobes that continue medially towards the mouth [45]. (D) S. ellipticus Götte’s larva with discrete ciliary tufts on the oral hood, dorsal lobe and ventro-lateral lobes (personal observation). (E) P. canadensis Müller’s larva with a single but discontinuous band, breaks in ciliary band indicated with arrowheads [28]. (F) Amakusaplana acroporae intracapsular Müller’s larva with discrete ciliary tufts on eight short lobes [5]. ac, apical cilia; br, brain; cci, caudal cilia; epr, putative extraocular photoreceptor cells; dl, dorsal lobe; dll, dorsolateral lobe; fo, frontal organ; in, intestine; ll, lateral lobe; m, mouth; oh, oral hood; ph, pharynx; rc, putative rejectory cells; rh, rhabdites; rpr, rhabdomeric photoreceptor cells; vll, ventrolateral lobes; y, yolk.