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Show 650 PROF. F. J. BELL ON A CRINOID FROM [Nov. 14, DESCRIPTION OF PLATE XLVIII. Fig. 1. Psoitis (Lophothuria) peronii, n. sp. Upper view: nat. size. 1 a. ( ) . Portion of trivial surface (to show arrangement of suckers): nat. size. 1 b. Pharynx of P. peronii. 1 c. Spicule of P. peronii. 2. Psolus (Hypopsolus) ambulator, n. sp. Upper view : nat. size. 2 a. ( ) . Portion of trivial surface (to show arrangement of suckers): nat. size. 2 b. Outline view from the side, to show general configuration. 3. Enlarged view of portion of dorsal surface of P. regalis, to show the granular scales. 4. Enlarged view of portion of dorsal surface of P. fabricii, to show the granulated plates. 5. Note on a Crinoid from the Straits of Magellan. By F. JEFFREY BELL, M.A., F.Z.S. [Received October 23, 1882.] In the last set of specimens received from Dr. Coppinger (Surgeon, H.M.S. ' Alert') is a single example of a Crinoid from the Straits of Magellan, which, by some accident, was not forwarded along with the other Echinodermata sent by him some time ago. In giving an account of that collection to the Society **, I directed attention to the absence of any representative^ the Crinoidea; and I might have added that, so far as I knew, no other explorer of the marine fauna of the region from which it came had been able to meet with one. It was therefore with considerable interest that I noted the arrival of this specimen in the British Museum; and I m a y add that I looked upon it with no little astonishment, as I conjectured how Dr. Coppinger must have doubted within himself whether he were really south of the Equator, and not again in those Arctic regions where Antedon eschrichti is so abundant; for it requires not only some acquaintance with specific characteristics to be able to detect any difference between the northern and the southern forms, but such differences as there are are exceedingly minute. I have endeavoured to examine fully and carefully into the characters of the single, not quite complete, specimen of the Antarctic form ; and although one m ay detect, on comparison with any given Arctic specimen, certain differences, such as may be expressed by saying that the cirri are a little more delicate, or not quite so long, or that a rather more distal joint is the longest of the series, yet marks such as these cannot be held to be distinctive of any thing more than of individuals. When, however, we examine the pinnules, we find differences which enable us to distinguish the one from the other. As is well known, the pinnules at about the middle of the arm in A. eschrichti have the two basal joints of a notable shape, and so formed as to leave an interspace between them ; in the Antarctic form, on the 1 P. Z. S. 1881, p. 87. |