The genus Amphiura is represented in the New Zealand fauna by some fifteen species known hitherto, to which is now added a further species from littoral waters of Cook Strait. All but one of the species are endemic to the New Zealand region. Most of them are rather small forms, but three—namely, Amphiura aster, A. rosea, and A. norae—reach or exceed an armspread of 100 mm. Of the latter, A. norae, Benham (1909) has hitherto been unique in possessing an almost naked aboral disc surface, with paired tentacle scales. However, both these features prove now to be shared by another large Amphiura trawled by Mr. F. Abernethy in Cook Strait; the species is here described as Amphiura abernethyi sp.nov. The chief distinction between A. norae and A. abernethyi may be seen from the following comparisons:—.

Amphiura norae	Amphiura abernethyi
Radial shields separated by an intervening space which is but little broader than the width of one shield, and occupied by five to seven mosaic platelets.	Radial shields widely separated, the intervening space occupied by about 25 to 30 polygonal mosaic platelets of varying size.
Lateral arm-plates bearing each four arm-spines.	Lateral arm-plates bearing each five arm-spines, the upper four directed outwards from the arm, the lowermost directed distally, parallel to the axis of the arm.

In addition, there are easily observable differences in the shapes of the radial shields and of the arm-plates, as can be appreciated by comparing Benham's (1909) figures with those given here. Notable is the attenuation of the proximal part of the radial shield in Amphiura abernethyi and the curvature of the whole plate, both features not apparent in Benham's figures of Amphiura norae.