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Show 1881.] 'LIGHTNING' A N D ' P O R C U P I N E ' EXPEDITIONS. 695 4. LEPTON LACERUM1, Jeffreys. L. lacerum, Jeffr., Les Fonds de la Mer, 1872, p. 84, pi. ii. f. 11, 11«. S H E L L roundish-oval, nearly flat, solid for its size, semitransparent, and glossy : sculpture, numerous close-set and very fine concentric strise, which are stronger towards the front: colour clear white : epi-dermis inconspicuous : margins rounded at the sides and in front, but at the back exhibiting on each side of the beak, and at equal distances, a small spike-like projection, giving that part a jagged appearance : beak small, central, and semioval: hinge-line tricuspid, occupying about one sixth of the circumference of the shell: cartilage-pit narrow and perpendicular: hinge-plate broad and strong : teeth (in the only specimen here described), one small and obliquely placed cardinal, and a rather long ridge-like lateral, which is also placed obliquely on each side of the beak: inside glossy : scars slight. L. 0*1, B. 0*1125. 'Porcupine' Exp. 1870: Atl. St. 1. A single valve only. Distribution. Bay of Biscay and Mediterranean ; 35-70 fms. This is a small shell; but I am at a loss to imagine why, on that account, the Editors of the excellent ' Journal de Conchyliologie' should have made the remark that as to such shells, " les caracteres n'indiquent pas toujours avec certitude l'age adulte." SCINTILLA ROTUNDA2, Jeffreys. (Plate LXI. fig. 1.) S H E L L roundish, with an obliquely triangular outline, nearly flat, solid, opaque but glossy ; sculpture, a few slight concentric lines of growth, which are more distinct towards the front, besides some minute irregular pit-marks as in other species of this genus : colour milk-white : epidermis none : margins gently rounded in front and at the sides, somewhat sloping from the beak on the left hand : beak minute, semiglobular or calyciform : hinge-line very short, obtusely triangular: cartilage-pit narrow and placed obliquely : hinge-plate also narrow : teeth (in the single valve here described) consisting of a minute cardinal, and of a ridge-like lateral on each side of the beak ; the lateral tooth on the left side is much larger than the other, which commences with an angular point: inside polished, but slightly pitted: scars indistinct. L. 0*1, B. 0*1. 'Porcupine' Exp. 1870: St. 27. Distribution. Palermo; 48-70 fms. {3Ionterosato, as Vasconia rotunda !). The hinge of this species does not quite agree with the description of the genus Scintilla given by Messrs. Adams ; but the remarkable texture of the shell is similar, viz. (to use their own words) " the external appearance of some of the species, which consists of a multitude of very fine punctations, of an opaque white colour, upon the shell, and which deprives them, in such portions, of their transparency." This peculiarity appears to be owing to the want of homogeneity in the composition of the shell. 1 Torn. 2 Pound. |