Second tentacle-pore opening entirely within the oral angle, so that the latter is closed by oral papillae; genital bursae and genital clefts present. Radial shields small, restricted to edge of disc at base of arm. . . . Ophiochytra Lyman, 1880.

*epigrus Lym., 1883. C. Pacific. 2,400 fms.

Second tentacle-pore opening more or less outside the oral angle, so that the latter gapes; genital bursae and genital clefts absent; radial shields conspicuous, not restricted to edge of disc. . . . Amphilepis Ljungman, 1866.

*Amphiura norvegica Ljung., 1864. Norway. 200 fms.