Fig. 8

Morphology of the tornaria larva of Schizocardium californicum between 50 dpf and the end of the larval stage. Light DIC micrographs of live larvae. All panels are anterior to the top and lateral views are ventral to the left. a-k Tornaria larva at 50 dpf. b, d-e Surface views showing external morphology and organization of the ciliary bands. a, c Optical sections through the middle of the larva, showing internal anatomy. f-g Close-up view of the anterior end of the larva, showing regression of the apical strand. Arrows indicate where cells of the apical strand are no longer present. h-i Dorsal view of the protocoel region, showing the gradual movement of the proboscis vesicle towards the protocoel. j-k Growth and shape change of the posterior coeloms between 50 dpf (j) and 65 dpf (k). l-p Tornaria larva at 65 dpf. l-n Optical sections through the middle of the larva, showing internal anatomy. m, o-p Surface views showing external morphology and organization of the ciliary bands. q-t Morphological changes occurring between 65 dpf and metamorphosis. q-r Close-up view of the pharynx, showing development of gill bars. s Close-up view of the protocoel in its final form before metamorphosis. t Close-up view of the metacoel in its final form before metamorphosis. as, apical strand; gb, gill bar; i, intestine; ldl, lower dorsal lobe; lg, lateral groove; ll, lateral lobe; m, mouth; mes, mesocoel; lv, lateral view; met, metacoel; of, oral field; og, oral groove; p, protocoel; pd, protocoel duct (pore canal); pdl, primary dorsal lobe; pds, primary dorsal saddle; ph, pharynx; pof, postoral field; post, postoral loop of the circumoral ciliary band; pre, preoral loop of the circumoral ciliary band; prf, preoral field; pvl, primary ventral lobe; pvs, primary ventral saddle; s, stomach; t, telotroch; v, proboscis vesicle; vs, ventral saddle. Scale bars: 400 μm (a), 200 μm (f-k, q-t), 800 μm (l)