Mucroplana caelata Sopott-Ehlers & Schmidt 1975

Mucroplana caelata Sopott-Ehlers & Schmidt, 1975 Mucroplana caelata Sopott-Ehlers & Schmidt, 1975: 208–210, pl. 8 fig. a–b (type locality: Santa Cruz Island, Galapagos Archipelago, Ecuador). Mucroplana caelata – Faubel 1983: 41–42, fig. 5 (identification keys). — Westheide 1991: 44 (mentioned only). Distribution Santa Cruz Island, Galapagos Archipelago, Ecuador. Habitat Interstitial (coarse intertidal sediments) or rocks. Remarks Mucroplana caelata could be considered a very primitive species because the most unique organizational feature within the polyclads: the proximal concentration of the extraepithelial prostatic glands. The family Mucraplanidae is characterized by the absence of a true prostatic vesicle, but it presents a peculiar structure in the distal ejaculatory duct, which expands to form a bulbous organ. This organ can assume the function of a seminal vesicle by storing sperm (Faubel 1983).