Description
Rays five, long and slender, tapering gradually. R. = 40 mm. r. = 7 mm. Br. = 7.5 mm. Disc and rays flat, interbrachial arcs subacute. Abactinal surface, exclusive of superomarginals, covered by plates ranging in diameter from 0.5 mm. to 2 mm. and not arranged in any regular order, either longitudinally or transversely. The largest plates, which are few in number, are, like their smaller fellows, evenly clothed in dense granules, but differ from these latter in having their central granules much larger and more conspicuous. The largest abactinal plates are strongly convex, while the smaller plates around them are nearly flat. No centrally naked plates occur anywhere on the specimen. In the figured type specimen some plates have been deliberately denuded to see if a plate similar in appearance to some of those in cumingii and allies could be produced. No such result was obtained, and in no way could the smooth bald effect so characteristic of cumingii be produced by rubbing away the granular covering.

Superomarginals 17-19 arranged in an irregular series, made up of alternating larger and smaller plates. The large plates of the series are strongly convex, and the smaller ones almost flat. The large plates are clothed in dense granules, coarsest centrally, while the smaller plates are evenly granulated all over. The alternation of the superomarginals is not perfect. The first superomarginal of each series is not conspicuously enlarged. Terminal plate very small, smooth, bare, slightly swollen, and bearing two or more terminal tubercles. Papulae isolated, not arranged in any  regular order; confined to abactinal surface, though occasionally some may occur between the marginals.

Inferomarginals 18-21; they are of varying form, making a somewhat irregular series. Most are large and have their central granules enlarged as in the superomarginal series. Odd plates occur here and there between the marginals.

Adambulacral plates numerous, 50-68. Each is provided with two conical flat-sided furrow-spinelets which may be sharply pointed or bladelike. Further, each adambulacral plate bears, in addition to a wealth of small granules, a central conical spine-like granule, which is either absent or only ill-defined in plates near the mouth. Only two series of actinolateral plates occur. The first series runs almost the entire length of the ray, and numbers, in the largest rays, between 27 and 32. The second series is comprised of from 2-3 plates and ends between the second and third superomarginal. All actinolateral plates, except those near the mouth, are clothed in dense granules and bear centrally a mass of prominent granules conical in shape and distinctly larger in size than those anywhere else on the specimen. These granules on the actinolateral plates are so conspicuous that they can be detected with the naked eye. Oral spinelets small, the innermost largest. Oral plates clearly defined by channel-like deficiencies in the granulation. No pedicellariae.

Etymology

• Celerina: Celerina was created by A.M. Clark in 1967. He didn't explain his choice. In Latin, Celerina it's a woman birth name "Célerine".
• Effernani: Named for N. S. Heffernan, Esq., formerly Deputy Commissioner for the Western Pacific, Honorary Correspondent to the Australian Museum. As a guest of this gentleman, the author and a colleague were able to accomplish extensive scientific work in the Santa Cruz Islands.
• Original description: Ferdina heffernani Livingstone, 1931 - Type locality: S.E. side of Santa Cruz Island, Santa Cruz Group, Western Pacific. Collected by E. le G. Troughton and A. A. Livingstone, August, 1926. It was collected alive on sand in a sheltered coral pool in about six feet of water at low tide.