_Mitrae papalis, episcopalis, &c._ OBS. _Testa plerumque laevi ad basin obtusa, truncata, labio exteriore margine crenato, gula laevi._ * * * * * GENERIC CHARACTER. Shell unequally fusiform; spire lengthened, attenuated; outer lip simple not toothed within. Columella plaited. DIVISIONS. I. Aperture narrow, linear, above angulated, below a little contracted. _Mitrae vulpecula, plicata, &c._ OBS. Shell generally longitudinally plaited, equally fusiform; outer lip smooth, slightly waved; top of the inner lip much thickened within; throat striated. II. Aperture above pointed, below narrowed, externally curved. _Voluta mitra-abbatis._ Chemnitz, &c. OBS. Shell generally with an elongated spire, the aperture below narrowed; upper syphon or channel small or wanting. III. Aperture above pointed, externally straight, below rounded, widened or effuse. _Mitrae papalis, episcopalis, &c._ OBS. Shell generally smooth, the base thick and truncated; margin of the outer lip crenated; throat smooth. The smaller shells of this division connect the genera _Mitra_ and _Colombella_ (Lamarck). * * * * * SPECIFIC CHARACTER. _M. testa angusta, basi cancellata; spira plicis carinatis; interstitiis sulcis transversis confertis; columella 4-plicata; gula 4 aut 5 striis remotis._ Shell narrow, base cancellated. Spire with carinated plaits, the interstices with slender, crowded, transverse grooves. Pillar of four plaits; throat with four to five remote striae. * * * * * This superb shell is figured from a matchless specimen brought home by that illustrious and lamented patron of science, the late Sir J. Banks, from the Pacific Ocean: it is now, together with his entire collection of shells and insects, in the Museum of the Linnaean Society. It is of great rarity, and the present specimen far exceeds in size any I have yet seen. A very perfect one exists in my father's collection which measures only two inches one line long: it differs slightly in wanting the lower white band and its inferior border: there is also an additional small plait between the second and third, a variation not uncommon in the Linnaean Volutes, and which lessens the importance of this character as a specific distinction. It is unfigured, and I believe undescribed, unless perhaps in Solander's MSS. In its small state it may have been overlooked as one of the numerous varieties of _M. vulpecula_; but the sharp angulated plaitings, the cancellated base, and the numerous faintly-grooved lines on the spire, as well as the more slender and lengthened form, will at once distinguish it: its colours also are very striking and dissimilar. * * * * * Pl. 24 [Illustration]