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Show 360 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [May 20, periphery ; base and nucleus ribless ; the whole surface of the shell (except the nucleus) is covered with extremely numerous and close-set spiral striae, which are discernible only with the aid of a microscope : colour glassy : spire rather long, and gradually tapering to a blunt point: suture slight: whorls 6, besides the nucleus, which is spirally twisted and intorted ; the last or body-whorl occupies two fifths of the spire : mouth oval, acutangular above and curved below : outer lip thin: inner Up inconspicuous: umbilicus none, but the base is shallowly excavated. L. 0*075. B. 0.035. ' Porcupine ' Exp. 1870 : Atl. St. 13. Half a dozen living specimens. This beautiful little shell may be distinguished by the numerous microscopic spiral striae, as well as by its shape and prismatic lustre. 42. ODOSTOMIA ATTENUATA *, Jeffreys. (Plate XXVII. fig. 4.) S H E L L club-shaped, thin, semitransparent, and very glossy : sculpture, long, sharp, and curved longitudinal ribs, from 18 to 20 on the last whorl, and with equally broad interstices; these ribs are not continued beyond the periphery, and in one specimen they nearly disappear on the last whorl; apex quite smooth : colour whitish, with a faint tinge of yellowish-brown : spire elongated, and gradually tapering to a blunt and apparently truncated point: suture well defined : whorls 6, exclusive of the nucleus, which is globular, spiral, and intorted ; the last whorl occupies two fifths of the spire : mouth and lips as in the last species : base sloping. L. 0*125. B. 0*035. ' Porcupine ' Exp. 18/0 : Atl. St. 1 7 ; Med. 55. Distribution. Gulf of Marseilles (' Travailleur ' Exp.), off western coast of Africa ('Talisman' Exp.) ; 363-1259 fms. 43. ODOSTOMIA COMPRESSA2, Jeffreys. (Plate XXVII. fig. 5.) S H E L L cylindrical, compressed in the middle of each whorl, rather thick, semitransparent and glossy : sculpture, sharp and straight longitudinal ribs, which commence at the top of each whorl and more or less disappear at the periphery ; their number is about 25 on the last whorl; they are usually of the same breadth as the interstices, but occasionally narrower ; base and apex quite smooth : colour whitish, with a broad but obscure spiral band of reddish-brown in a young specimen : spire turreted, elongated and gradually tapering: suture narrow but distinct : ivhorls 10, flattened, contracted in the middle of each; the last occupies about two fifths of the spire ; nucleus twisted : mouth oval, acutangular above, rounded below : outer Up incurved, and flexuous in the middle : inner Up thickened and somewhat expanded : base sloping. L.0*25. B. 0*075. 'Porcupine' Exp. 1870: Atl. St. 17, 36; Med. 40, Benzert Road. Distribution. Gulf of Marseilles (' Travailleur' Exp.), off the west coast of Africa, C Verd I., and Azores ('Talisman ' Exp.), off the Azores (' Challenger ' and ' Talisman ' Exp.) ; 363-1622 fms. 1 Attenuated or narrowed. 2 Pressed or squeezed together. |