Planocera pellucida

Planocera pellucida (Mertens, 1833) Planocera gaimardi Blainville, 1828: 579 (description). Planaria velellae Lesson, 1830: 453–454 (description). Planaria pellucida Mertens, 1833: 8 (type locality:? Atlantic Ocean). Planaria oceanica Darwin, 1844: 246–247, pl. 5 fig. 1 (description). Stylochoplana tenera Stimpson, 1857: 11 (description). Stylochus pelagicus Moseley, 1877: 23–29 (description). Planocera simrothi Graff, 1892: 190, 200–205 (description). Planocera pellucida – Örsted 1844: figs 20–21 (new combination). — Woodworth 1894: 49–50 (new record from Central America, off the coast of Oaxaca (at the surface, 8 p. m.; 13°33′30″ N, 97°57′30″ W). — Faubel 1983: 77–79, figs 20–21a–b (re-description and new record from Red Sea). Carenoceraeus oceanica – Schmarda 1859: 14 (description). Planaria pellucida – Prudhoe 1950: 710–713 (new record from Atlantic Ocean, Cape of Good Hope and north of Cape Verde Island; Sargasso Sea; east of Ushuaia; Southern Ocean; India Ocean, Port Natal, S. Africa; Pacific Ocean, west coast of New Guinea, south of Galapagos Island, Juan Fernandez Island, Chilean coast, Japan). Distribution Central America, off the coast of Oaxaca; the Red Sea, the Indian Ocean, the northern and southern regions of the Atlantic Ocean in the northern and southern region of the latter, and the Pacific Ocean. Habitat Pelagic and symbiont (occupies the mantle cavity of Janthina janthina (Linnaeus, 1758) (Faubel et al. 2007: 429)), preferably in 18°C water mass. Remarks Faubel (1983) redescribed the species from samples belonging to the neuston, collected in the Red Sea and the central and southern region of the Atlantic Ocean. The species is characterized by a translucent elongated body with a light yellowish-brown granular pigmentation on the dorsal region, cerebral and tentacular eyes, the latter distributed in the periphery (only in the internal region) of the nuchal tentacles, and central pharynx with an oral opening located at the end of the last third of the pharynx. The male reproductive system has spermiducal vesicles, spermiducal bulbs, a seminal vesicle and a prostatic vesicle, and a cirrus sac armed with sclerotial spines. The female reproductive system has a bulbous vagina and lacks Lang’s vesicle.