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Show 1881.] PROF. F. J. BELL ON THE GENUS ASTERIAS. 511 On comparing this with one of Mr. Norman's specimens, in which R= 16, r=3, we are at once struck by the greater development of spines on the abactinal surface cf the latter, where it is possible to make out five very distinct rows of spines, while in the former only three are to be accurately distinguished. In consequence of this difference the specimens do not, as may be imagined, present any very close resemblance. When we refer to the original description of Sars we find some explanation; for he says, " Auf dem Riicken derselben 3-5 Reihen, von denen 3 deutlich, die 2 anderen weniger deutlich oder hiiufig unvollstandig sind." Though no two specimens in the set of seven which were taken off Shetland differ from one another so markedly as do the two just referred to, yet they differ sufficiently to show that the specimens of the species which are found in the British Seas, just as much as those found off the Scandinavian coasts, do vary, in this particular, within very wide limits. The spines on Mr. Norman's specimens seem to be sharper and rather longer than those on the specimen named by Dr. Liitken. The proportions, and the resulting general appearance, are very much the same ; and I can see no reason why the specimens should not all be regarded as members of the same species. The above discussion contains an answer to the third question ; for in demonstrating the characters of A. muelleri it proves the distinctness of that species from A. glacialis. The consideration of exceptional forms from the British seas may well be postponed for further information and a larger series of specimens. In here describing some forms under new names I am taking the course which, after careful consideration, seems to me to be at present that which is best adapted for the advancement of science. The exact limits of the species of this genus can only be defined by enermous collections. DESCRIPTIONS OF NEW OR RARE SPECIES. ASTERIAS PHILIPPII, sp. nov. (Plate XLVII. figs. 1, la.) It is necessary to make this new species for two specimens preserved in alcohol, and forming portion of the oldHaslar collection ; they were collected by J. O. Goodridge, Esq., Surgeon R.N., and are stated to have come from "South America." General formula *j2maa'. Rays six, rather stout; disk moderate; adambulacral spines in two rows, madreporic plate single, anechinoplacid, lateral and actinal spines autacanthid-general formula V2maa. The adambulacral spines present a remarkable appearance, owing to their small size, their delicacy, and their close packing ; in addition to this the integument around them is raised up into processes almost as long as the spines, and thus increases the appearance of crowding. A well-marked groove separates these from the outer spines, of which there are two rows on the actinal surface, while a third occupies the side of the ray. All these spines, the best-developed of which may be as |