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Show 88 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Mar. 6, 2. On the Mollusca procured during the ' Lightning' and < Porcupine' Expeditions, 1868-70. (Part VI.1) By J. G W Y N JEFFREYS, LL.D., F.R.S., F.Z.S. [Received February 23, 1883.] (Plates XIX., XX.) GASTROPODA (continued). Family VI. SCISSURELLID^E. 1. S C I S S U R E L L A CRISPATA, Fleming. S. crispata, Flem. M e m . Wern. Soc. vi. p. 385, pi. 6. f. 3 : B. C. iii. p. 283, pi. vii. f. 2 ; v. p. 201, pi. Ix. f. 3, 3a, 3b. 'Lightning' Exp. St. 2, 5. 'Porcupine' Exp. 1869: 14, 25, 36 (var. aspera), 70. 1870: Atl. 1, 2, 6, 9, 13, 16-1 7a, 24, 27-30, Tangier B. (and vars. angulata and aspera) ; Med. 45, 50, Adventure Bank, off Rinaldo's Chair (var. aspera). Bistribution. From Spitzbergen to Sicily and Azores, and from Greenland to N e w England ; 4-790 fms. Fossil. Pliocene: Coralline Crag, Italy, Rhodes. Post-tertiary : Norway and Sicily. S. angulata of Loven and S. aspera of Philippi are varieties ; the latter corresponds with m y variety paucicostata. 8. angulata is larger, and S. aspera more conical with stronger and fewer striae. The height of the spire and consequent contraction of the umbilicus, as well as the number and strength of the riblets and spiral striae, are variable characters. The variety aspera is more peculiarly Mediterranean than the typical form. The animal was fully described by m e in the ' Annals and Magazine of Natural History ' for June 1870. 2. SCISSURELLA UMBILICATA2, Jeffreys. (Plate XIX. fig. 1.) S H E L L forming a depressed sphere which is equally raised above and below, rather thin, semitransparent, and somewhat glossy: sculpture, none except very fine and close-set, but indistinct, lines of growth : colour white : spire slightly raised : whorls 4-5, flattened above and sloping outwards; they rapidly enlarge, so that the last or body-whorl considerably exceeds in size the rest of the shell: slit long and central, equal in width, with upturned edges : mouth nearly circular, but somewhat angulated where it is united to the body-whorl below tbe peripheral keel: peristome continuous, although not free in consequence of the inner lip being attached to the shell: outer lip thin and sharp : inner lip spread on the lower 1 For Part I. see P. Z. S. 1878, p. 393; for Part II. see P. Z. S. 1879, p. 553; for Part III. see P.Z.S. 1881, p. 693; for Part IV. see P.Z. S. 1881, p. 922; and for Part V. see P. Z. S. 1882, p. 656. 2 Umbilicate. |