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Show 422 PROF. F. J. BELL ON THE ECHINOMETRIDsE. [Mar. 15, ECHINOMETRA LUCUNTER (Lamk.). Questions of identifications of species are in some cases interminable ; and we seem here to have an example of one in which there would be found much to say on both sides, were it worth the while, and were questions of synonymy the end of zoological science. I shall not, I imagine, be accused of any blind following of Prof. Alex. Agassiz; but I follow him in this case for what, I submit, is a sufficient reason. The labels of Linnaeus's specimen of E. lucunter are lost; Leske found it difficult to decide to what figure of Klein's Linnaeus meant to refer : Lamarck's typical specimens are in existence. The reviser of the group having to settle what species he would call E. lucunter, came to the conclusion that he would follow Lamarck. Whether the present writer would have done the same, had he been the reviser, need not be discussed ; it is certain that had Prof. Loven or Dr. Liitken been the revisers, they would have adopted a different course (cf. Agassiz, op. cit. p. 284). But a decision has been given; it is almost certain that no further light will ever be thrown on the difficulty; the 'Revision of the Echini' is our present standard. Let us, then, when we cannot oppose facts to facts, but only opinions to opinions, follow the Reviser, and let the question (and all such questions) drop. Large forms of this species differ so much in appearance from smaller specimens, that, where the series fails, one is at once almost inclined to imagine that one has to do with a distinct species. One specimen in the national collection (which has its longest axis 79 and its morphological axis 76 millim. long) is greatly bowed on its actinal surface, and has the smaller tubercles exceedingly well developed ; there is a large number of very small anal plates; here and there five pairs of pores are found in an arc. But the most striking variation, and one which, in our present state of information, we should almost be justified in taking as a basis for the formation of a distinct variety, represented by this form, lies in the characters of the auricular arch : there is a considerable development in the amount of calcareous matter there laid down; the arch is consequently very strong, the foramen very small, the top piece is well developed, and the connecting ridge, instead of being low, is nearly half the height of the whole arch. The plates on the buccal membrane are very large ; and the ends of the radii in the lantern of Aristotle are well developed. On the other hand, the characters of the auricular arch are not very constant in this species; and the proportions of the parts of the specimen in question are not at all unlike those of a specimen 76 millim. in diameter, the measurements of which are given in the ' Revision of the Echini;' so that better service is done by directing attention to its peculiarities than by imposing a new name on this already heavily weighted species. Two specimens, purchased in 1844 from Mr. Gould, bear the locality of " Abrolhos." I am unable to distinguish them from other specimens of E. lucunter ; and I can hardly suggest that the locality given in the Register is altogether wrong; for one specimen, at any |
