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Show 516 DR. HUBRECHT ON A NEW PENNATUL1D. [May 19, they were in spirit. This would also explain how it was that internally all traces of cell-structure had vanished, that no staining methods were of any use, &c. Careful preparations of parts of the rhachis-wall spread "out and looked at from the inside, showed that the polyparia indeed contained polyps (and that the zooids did not), moreover showed remnants of the mesenterial filaments, but how the internal soft parts were respectively related could not possibly be made out. I must leave this to a more fortunate student of specimens in the fresh state. There only remains for us to inquire whether the structure of the polyparium, as we have described and partly figured it, will enable us to decide about the degree of relationship which the new genus, proposed to be called Echinoptilum, has to the other genera and groups of Pennatulids. It is undoubtedly amongst the less specialized families of Seapens that we must look for its nearest allies; and were it not for the incipient differentiation of a dorsal and ventral surface, and more especially for what sections teach us in this respect, we should feel inclined to arrange Echinoptilum in the very lowest section-the Veretilleae, which, by the radial arrangement of the polyps round the rhachis, still more closely approach the x'Ucyonaria s. str. (Alcyo-nida &c). For the reasons just recalled to mind we have, however, to arrange the new genus in Kolliker's other large section, that of the Spicatse, which is characterized by a bilateral arrangement of the polyps on the rhachis. In this section the less differentiated families of the Kophobelemnonidae and the Protoptilidae have several structural peculiarities in common with Echinoptilum ; and the new genus of Protoptilidae, Gunneria, only very lately described by Danielssen and Koren1, more especially resembles Echinoptilum in its very massive development of needle-like calcareous elements in the sarcosoma. Moreover the external appearance of the individual polyp-cells in Echinoptilum and the arrangement of the spicules in the wall of these is met with in other Protoptilidae. The general aspect of Echinoptilum, its shortness and club-shape, more especially resembles that of Kophobelemnon, the Protoptilidae being long and slender, and their polyparia reminding one of the unbranched Gorgonidoe. The calcareous needles also are very profusely represented in the investment of the Kophobelemnonidae, but are not found in the internal delicate framework of this family, whereas, on the contrary, in Echinoptilum we find it thickly beset with them. Again, the individual polyp-cells of the Protoptilidae have more resemblance to Echinoptilum than those of Kophobelemnon, where they are much less marked and projecting. On the other hand, we must not lose sight of the fact that with another section of the Spicatse, viz. the Funiculineae, Echinoptilum has also more than one point of comparison, more especially with Kolliker's new genus Stachyptilum (' Challenger' Reports, vol. i. Pennatulids, p. 12, pi. viii. figs. 24-26). The polyp-cells hi Echi- 1 Der Norske Nordhavs Expedition, xii. Zoology, Pennatulida: Ohristiania, |