Ophiomastus tegulitius Lyman

• Lyman, T., 1882. Challenger Ophiuroidea, p. 100–1. Pl. 8.

Material Examined: None.

The holotype of the species is from Challenger Station 165, in 2,600 fathoms, 900 miles west of Cape Farewell. Further examples were taken at Station 166, in 275 fathoms, 199 miles north-west of Cape Farewell, so that the species is to be expected in Cook Strait.

Ophiomastus stellamaris Fell

• Fell, H. B., 1952. Zool. Pubs. Vict. Univ., 18, p. 30–2, Figs. 23–7.

Material Examined: The holotype and 10 other specimens, from Discovery Station 2733, in 300 metres, Chatham Rise; no other specimens have since been taken; the remarks made above, under Ophiomisidium irene, may well apply in this case also.

Ophiomastus admiral sp. nov. Plate 4, Figs. B, C, D, holotype.

Description: Disc pentagonal, tumid above. The centrodorsal is extremely large. It is surrounded by 5 small interradials, then the 5 primary radials. Two other interradial plates lie on the inter-radial axis of symmetry. One other radial plate occurs distal to the primary radial, wedged between the two radial shields at the base of the arm. The lower surface of the disc is mainly covered by the very large, obcordate oral shield; beyond this plate lie relatively few, and rather irregular, plates. The conspicuous genital clefts are equal in length to the first arm-joint, and lie beside it. The adoral plates meet narrowly within; distally, they meet both the first lateral and first ventral arm-plates. The oral angle is relatively wide and gaping, the 5 papillae flattened, square, adjoining one another so closely as to form a continuous series, the proximal and distal ones larger than the intervening ones. The upper armplates are fan-shaped, with a right-angled proximal apex and a rounded distal border, about as broad as long, not contiguous. The lateral arm-plates meet very narrowly above and below beyond the two basal arm-joints. They carry two conical spines, the lower one the larger, though scarcely half as long as its arm-joint. The ventral arm-plates are pentagonal, a little longer than broad, with an acute proximal angle, a broad convex distal margin, and concave lateral margins, within which the tentacle-pore is placed on either side. The single, large, round tentacle-scale is carried on the adjoining margin of the lateral plate.

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Material Examined: Four specimens including the holotype, all from 400 fathoms, Cook Strait, VUZ Station 87. Two poorly preserved juvenile ophiuroids from 300 fathoms, off east Otago, Dom. Mus. Station B.S.190, possibly belong to the same species.

Holotype: In the Department of Zoology, Victoria University of Wellington. R 15 mm, r 2·5 mm. Colour in alcohol white, colour in life probably pink (a mixed collection of ophiuroids from this station was so described, J. C. Yaldwyn).

Remarks: Ophiomastus admiral differs from O. secundus Lyman in that the arm-spines are not subequal, the disc contains a number of plates other than the primaries, and the oral papillae are separate. The two species agree in having a single large tentacle scale. O. admiral differs from O. tegulitius Lyman in having one large tentacle-scale (instead of two small ones). From O. stellamaris Fell the species differs in having two lateral (instead of one ventral) arm-spines, and the tentacle-scales are relatively and absolutely smaller, despite the fact that the body is larger than in O. stellamaris.