TEM and SEM micrographs of Osedax deceptionensis oocytes, sperm, embryos, and larvae a Oocyte (oo) in the ovaria packed within a collagenous layer (cl) containing yolk with protein (pro) and lipid (lip) inclusions, and glycogen (gly).

Oocyte surrounded by a follicle (fo) with muscular fibres (mu) with sperm (s) embedded, b Non-symbiotic cells (ns) with rough endoplasmic reticulum (er) producing proteins (pro) transferred to the oocyte (oo). Oocyte (oo), limited by a membrane (om), extending interdigitated cytoplasmic extensions (arrowed), c Blood vessel (bv) with several expansions close to a sperm (s). Notice the helically spiraled nucleus (n), the flagellum (fl), and mitochondria (mi) of the sperm, d Sperm (s) in longitudinal section. Notice the nucleus (arrowed), mitochondria (mi), and flagellum (fl), e Cluster of sperm (s) in transversal section, in an area surrounded by rough endoplasmic reticulum (er) close to oocytes. Inset showing a detail of a sperm in transverse section with the nucleus (n) and mitochondria (mi), f Trochophore-like larva, inside the female’s tube, filled with protein and lipid vitellogenic content. Ciliary bands (ci) present. Notice a membrane (m) limiting the larva and nucleus (n) of larval cells. Inset showing a SEM micrograph of a developing embryo inside the female’s tube.