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Show 381 MR. R. B.WATSON ON MADEIRAN MOLLUSKS. [Mar. 18, Spiral threads on the base 5-6, very faint and shallow ; the lowest two close to the pillar are sometimes a little stronger than the others ; of these a very doubtful trace sometimes appears above the periphery. On the upper part of the whorls near the suture a multitude of very sharp, minutely microscopic, superficial spiral frettings are visible. The If whorls are embryonic, and have an independent set of very fine, microscopic spiral lines, about seven in number. Colour fundamentally a yellowish white, of a horny transparency ; but in fresh shells this is so tinged with a suffused rich chestnut that the fundamental colour only shows through on the base (where it appears as a broad band) and, somewhat less purely, in a band above the periphery, which band is visible on the penultimate whorl, but disappears higher up, so that the upper whorls are of a uniform pale chestnut. There are thus on the body-whorl a chestnut band close to the suture, a narrow clear band below this, a broad chestnut band at the periphery, and a clear whitish band occupying the whole base except the centre and belly-lip, which are stained with a deeper and richer chestnut than any other part except the suture behind the lip, which is also very dark. In the dead shell this chestnut has a great tendency to fade. In rare instances (two among some hundreds) these chestnut bands on the body-whorl show a tendency to break up into spots, large and squarish near the suture, longer and inclined to part in the middle in the peripheral band. In the full-grown shell the lip-edge is generally occupied by a broad clear white band. Spire short and above the body-whorl attenuated, terminating in a small but blunt round top. The contour-lines of the right and left sides of the shell are very dissimilar, the right being very flat, while the left is immensely arched. Whorls 4-5, slightly rounded ; the last is disproportionately large and ventricose. Suture a mere scratch, being the less distinct from the extent to which the lower whorl laps upon that which precedes it; defined by a remote (generally)dark brown line, produced by the shining through of the preceding whorl. Mouth oval, across the belly a good deal flattened, above very slightly, but at last very sharply pointed, large and a little patulous all round. Outer lip thin, transparent white (though sometimes the brown bands advance up to the very edge), with a free continuous sweep all the way round. Inner lip stained with intense brilliant chestnut; on the umbilicus a little reflected, so as to leave behind it a very narrow but not shallow chink; carried across the belly by a rather thickish callus, which is a little bevelled outwards. Operculum extremely thin and smooth, with scarcely any trace of circular divergent lines, but with one strong longitudinal line parallel to the inner margin. Sh. M. 5. 4. 3. 2. 1. L. ...*05 *025 *026 *013 *006 *003 001 B *033 *021 *021 *027 017 *009 *004 |