Ophiosphalma properum (Koehler, 1904) .

Figures 57 a, b

Ophiomusium properum Koehler, 1904 .

Ophiosphalma properum (Koehler); Guille & Vadon, 1986

Lectotype RMNH V.ECH. O. 2953, Siboga station 85 Makassar Straits, Indonesia, 724 m. There are 6 specimens identified by Koehler in the ZMA but none are designated as a type. I have selected the single specimen from Siboga station 85, as a lectotype. The remaining 5 are paralectotypes from station 314.

Main Features: Disc covered with poorly defined imbricating scales –the sutures are smooth. Radial shields separated by two squarish plates. Dorsal arm plates diamond-shaped with hyaline margins. Lateral arm plates lightly rugose. Heavy block-like oral papillae, partly separated. Three pairs of exposed tentacle pores each with a single scale. Long genital slits reaching from adoral plates to edge of disc (3rd lateral plate).

O. properum is similar to O. impotens— but the genital slits are longer, possibly indicating an older specimen.