Ophiomusium trychnum H. L. Clark 1911 .

Figures 37 a, b, c

Ophiomusium trychnum H. L. Clark, 1911; Irimura, 1982.

Holotype USNM E25646 Albatross station 5069 off Ose Saki, Suruga Gulf, Japan, 198– 240m. 47 paratypes USNM, all from Albatross stations in 1906, off Japan.

Main Features: Heavy tumid disc, plates mostly raised and spherical. Large radial shields, totally separated. Dorsal and ventral arm plates throughout arm. Oral shields small, up to 10 plates between them and disc margin. Six arm spines, 3 grouped low. Two pairs of exposed tentacle pores. Genital slits run from adoral plate to end of second lateral arm plate.