Fig. 3

Galathowenia oculata. The general structure of cerebral eyes. a, b) LM of semi-thin sections, c) TEM; a) Cross-section behind the mouth and pigmented eyes spots, note the lateral position of the ring-like brain inside the epidermis (encircled), on the left epidermis with numerous gland cells (gl, stained in pink); b) Brain (br, encircled in yellow) with an adjacent eye (ey, encircled in red) located dorsally, eye not distinctly set off from surrounding tissue, pigment cells leave an upper, biconvex lens-shaped part without pigment (encircled in white); c) TEM of the ultrathin section adjacent to b with PSCs (psc) and PRCs (prc), nuclei (np, nr) arranged in two layers: those of PSCs (np) above those of PRCs (nr), basal region of the eye with a network of neurites (ne), boxed area enlarged in 3a. Abbreviations: br brain, coe coelom, cu cuticle, dbv dorsal blood vessel, ecm ECM, ep epidermis, gl glandular cell, g gut, lbv lateral blood vessel, n nucleus, ne neurite, np nucleus of PSC, nr nucleus of PRC, ph pharynx, prc PRC, psc PSC, pt peritoneum