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Show 580 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [J inside smooth and polished ; edge sharp and plain : scars indistinct. L. 0*225, B. 0*35. 'Lightning' Exp.: St. 3. 'Porcupine' Exp. 1869: St. 23, 23a, 65. 1870: Atl. 3, 9, 17, 17a. Distribution. Norwegian arctic Exp. 1878; 459-778 fms. Differs from L. jeffreysi in its somewhat greater size, being at all ages much broader in proportion to the length (and consequently more extended on each side), the anterior end not being upturned, and in the hinder margin being sharp-edged and pinched up. 18. LEDA MICROMETRICA, Seguenza. L. micrometrica, Seg. Nuc. terz. mer. d'lt. p. 21, t. iv. f. 22, 22 a-c. 'Porcupine' Exp. 1869: St. 23a. 1870, Med. 55. Valves only. Distribution. Sciacca, Sicily. Fossil. Pliocene. Trapani near Messina. I had previously given to this minute but distinct species the name oblonga, by which Monterosato called it. 19. LEDA EXPANSA, Jeffreys. (Plate XLVI. fig. 4.) L. expansa, Jeffr. in Ann. and Mag. N. H. Nov. 1876, p. 431. 'Porcupine' Exp. 1869 : St. 16, 30. Distribution. 'Valorous' Exp.; 690-1750 fms. 20. LEDA INSCULPTA1, Jeffreys. (Plate XLVI. fig. 5.) S H E L L transversely oval, equilateral, rather convex, moderately solid, semitransparent, and glossy: sculpture, numerous and regular but minute and fine concentric impressed striae, which become stronger towards the front and are wanting at the back : colour white : epidermis pale yellowish : margins sinuous at the back owing to the prominence of the beaks, equally rounded on both sides, and curved in front: beaks central, prominent: cartilage and pit minute, the latter sunken: hinge-line forming a very obtuse angle : hinge-plate rather broad: teeth small, sharp and comb-like, deflected outwards, 8-10 on each side of the beak; they are placed on the inner side of the hinge-plate : inside lustrous, microscopically fretted, plain-edged : pallial and muscular scars rather distinct, the former being broad. L. 0075. B. 0*115. 'Porcupine' Exp. 1869: St. 16. 1870: Atl. 16, 17, 17a. Differs from L. expansa in shape, convexity, and sculpture. 21. LEDA PUSILLA2, Jeffreys. (Plate XLVI. fig. 6.) S H E L L roundish-oval, equilateral, somewhat compressed, remarkably solid for its size, opaque and glossy: sculpture, numerous and close-set concentric and very fine microscopic striae, which cover the whole shell: colour whitish : margins rounded on every side, except at the back so far as the continuity is interrupted by the beaks, con- 1 Engraved. 2 Tmy. |