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Show 492 PROF. F. J. BELL ON THE GENUS ASTERIAS. [May 3 1. Contributions to the Systematic Arrangement of the Asteroidea.-I. The Species of the genus Asterias. By F. JEFFREY BELL, M.A., F.Z.S., Professor of Comparative Anatomy in King's College. [Received March 21, 1881.] (Plates XLVII. & XLVIII.). The amount of variation exhibited by the species of the genus Asterias has, as might have been expected, led to the formation of a large number of forms which are at any rate nominally distinct. Tempting as the work of revision of such a genus ought to be, it has never attracted the attention of any zoologist who has written on the subject since the time of Muller and Troschel (1842). The most important and comprehensive work which has appeared is that of M . le Prof. Edmond Perrier, of the Jardin des Plantes. This essay, which was originally published in that still young but already so fertile journal the 'Archives de Zoologie experimentale' of M. Lacaze-Duthiers, has since appeared separately1. M. Perrier's work, though bearing the unambitious title of 'Revision de la Collection de Stellerides du Museum d'histoire naturelle de Paris,' is so far extensive in its scope that it contains also a revision of the specimens in the British Museum, and descriptions of a number of the new species therein contained. In so far as Prof. Perrier has done his best to get their full value out of the descriptions of Dr. J. E. Gray, which, it must be owned, are peculiarly insufficient and unsatisfactory, and has also been in some cases bold enough to describe new species from single specimens, he has relieved me of two duties, which are always unpleasant. Much, however, as M . Perrier has done with and for the genus Asterias, it would be not proper to pretend to say that he has given a complete revision of the genus : he details only forty-nine species, and does but little to indicate the affinities of the species he mentions, and nothing at all as to resolving them into either natural or artificial groups. Nor can the present essay ask to be regarded as any thing else than a tentative effort in the direction of a complete revision. The collection in the British Museum is still in want of a number of described species ; while, on the other hand, we must wait for a more perfect monograph till the specimens, which were doubtless collected by the ' Challenger,' and are now being worked out under able hands elsewhere, shall have found their proper place in the stores of the national collection. The rich collection made under the supervision of Mr. Alex. Agassiz will soon be described by M. Perrier. 1 Paris (Reinwald, 1875). |