Family Ophiacanthidae
Ophiacantha M. & T., 1942

Ophiacantha vilis Mrtsn., 1924

• Off Cape Campbell, 50 fathoms, 1947; coll. F. Abernethy; one specimen.

The species has hitherto been known only from one record, that of the type material, which was taken in Cook Strait from 20 fathoms. That its range extends upwards to include the sublittoral region of the continental shelf is now evident: apparently, however, it is rare, since only one specimen was taken out of hundreds of other echinoderms trawled in the same area at the same time.

The specimen shows little sign of the outer lobe of the oral shield mentioned by Mortensen (1924), but in other respects it agrees. The species reaches a larger size than was hitherto supposed. In the present case, the radius of the disc is 3·5 mm., the major radius ca. 30 mm., giving the ratio R/r 8·5; thus the proportions noted by Mortensen are retained.