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Show 368 MR. R. B. WATSON ON MADEIRAN MOLLUSKS. [Mar. 18, Spiral threads 12 to 13, raised, rounded, shining; those on upper part of body-whorl are thrown out by the ribs into sharp points ; they are generally pretty equally parted by spirally scratched interstices a little broader than themselves ; on the base they are sometimes closer-set, aud sometimes are followed by a kind of miniature of themselves occupying half the interstice. The spiral scratchings of tbe interstices are extremely minute ; and though more distinct than in R. moniziana, they do not interfere with the gloss of the surface as they do in R. crispa ; about six go to each interstice. There is a broad, thick, white labial rib, which is strongly scored across by the spiral threads ; and between these the interstitial scratches are plainly shown ; but all these disappear just short of the mouth, which is edged by a thin and narrow border in advance of the labial rib ; this border is well scored longitudinally. Colour orange (whence the name), with a slight dash of brown, in some cases paler, in others darker, but with little variety, and quite uniform in each specimen, except that sometimes, though rarely, the first whorl has a shade more of brown. The labial rib is whiter than the rest of the shell. Spire long, very little contracted upwards, rising but slightly in steps, ending in a depressed round apex, which is always higher on the side where the extreme embryonic tip stands up. Whorls 4 to 5, fully rounded, of regular increase. Suture deep, little oblique. Mouth very round, obtusely pointed above and encroached on by the belly; not open, except a little in front aud on the pillar. Outer Up much thickened by the labial rib, but on its extreme edge sharp and thin, slightly expanding below. Its exterior profile, as the shell lies on its back, is formed by the labial rib bearing as knobs the ends of the spiral threads. Inner lip consists of the projecting edge of the outer lip, which sweeps continuously round ; on the pillar it is a little reflected, and has there a sharp but little-projecting edge, with an umbilical chink behind it; this chink is generally small and narrow, but is sometimes open and trough-like. The callus which carries the pillar-lip across the belly is thin and closely united to the body ; at its junction with the outer lip it seems always, in well-grown specimens, to project a little way out from the body to meet that lip. Sh. M. 5. 4. 3. 2. 1. L...-080 *027 *033 *018 *013 *008 *007 B.. .-042 -023 *03 *04 *03 *02 -013 Hab. Piedade (Canical), 15 to 35 fathoms ; Ponta de S. Lourenco, 25 to 45 fathoms ; Funchal Bay, up to 50 fathoms ; Porto Santo, up to 50 fathoms. I have named this shell from its colour. RISSOA STRIATA, Adams; var. LIRATA, Watson. (Plate XXXIV. %• 4.) Not in M'Andrew's list. |