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Show 1881.] THE S U R V E Y O F H.M.S. 'ALERT.' 95 it will be easy enough to call it L. luetkeni. I add the following short description :- Perfectly flat, with twenty-three completely developed and three less-well-developed arms ; brown above, with a dark line running round the disk, cream-white below ; the arms are very slender, and widest at some little distance from their point of insertion into the disk. The small and white madreporic plate lies near the dark circular line, and is fringed with a few spines. The spines on the arms form a median and a lateral series ; but the former does not extend along the whole length of the ray ; the arms themselves have the appearance of being ringed externally, owing to the transverse disposition of these spines; single or bifurcate spines, not very regularly arranged, are to be found on the disk, but are not numerous. 22=515, ?•= 14. Trinidad Channel, 30 fathoms. It is of interest to point out that in the three partly developed arms the ambulacral suckers are closely packed, and do not exhibit a definitely paired so much as a pycnopod arrangement; and this, which is characteristic of the adult Asterias, is pro tanto of value in supporting Dr. Liitken's view as to the affinities of the genus now under examination. The fact of the presence of three arms smaller than the rest should, further, be compared with the remarks on this subject made by Dr. Liitken (and translated in Ann. & Mag. Nat. Hist. ser. 4, xii. p. 336). PENTAGONASTER SINGULARIS, M. & Tr. Goniodiscus singularis, Miiller & Troschel, Archiv fur Naturg. (1843) ix. p. 116. Pentagonaster singularis, Perrier, Rev. des Stell. p. 222. One specimen, obtained in Tom Bay, 0-30 fathoms ; bottom, rock, kelp, and mud. This specimen is interesting as being intermediate in size between the two specimens already possessed by the Museum, and collected by Dr. Cunningham. PENTAGONASTER PAXILLOSUS. Astrogonium paxillosum, Gray, P. Z. S. 1847, p. 79. Pentagonaster paxillosus, Perrier, Rev. Stell. p. 221. A small specimen (12=19, r = 1 2 ; 20 infero-marginal plates), collected by Dr. Cunningham at Sandy Point, must be referred to this species. If it be distinct from it, the distinctive specific characters are not differentiated; the condition of the type specimen, which is dry, prevents a determination of the question whether the Australian form has a glassy spine at each angle of the mouth. If it shall prove to be absent, that character might perhaps be shown to be one of specific value, and would, at any rate, afford a point of distinction between the South-American and the Australian form. CALLIDERMA GRAYI, sp. n. (Plate VIII. fig. 5.) Arms not long, interbrachial angle rounded ; 22= 15, r=8. Ten |