Zoological Illustrations/VolI-Pl23

by William Swainson

MITRA vittata.

Ribbon Mitre.

Character Genericus.

Testa inæqualiter fusiformis, spirâ productâ attenuatâ; labio exteriore intùs edentato. Columella plicata.

Divisiones.

III. Apertura angusta, linearis, suprà angulata, infrà subcontracta.

Mitræ vulpecula, plicata, &c.

Obs. Testa plerumque longitudinaliter plicata, æqualiter fusiformis, labio exteriore lævi leviter undulato, interiore ad apicem intrà crassato; gulâ striatâ.

III. Apertura suprà acuminata, infrà angusta, extrinsecus curvata.

Voluta mitra-abbatis. Chemnitz, &c.

Obs. Testa plerumque spirâ elongatâ, aperturâ ad basin angustatâ, siphone superiore parvo aut nullo.

III. Apertura suprà acuminata, extrinsecus recta, infrà rotundata, dilatata, vel effusa.

Mitræ papalis, episcopalis, &c.

Obs. Testâ plerumque lævi ad basin obtusâ, truncatâ, labio exteriore margine crenato, gulâ lævi.

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Generic Character.

Shell unequally fusiform; spire lengthened, attenuated; outer lip simple not toothed within. Columella plaited.

Divisions.

III. Aperture narrow, linear, above angulated, below a little contracted.

Mitræ 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.

III. 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.

Mitræ 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).

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Specific Character.

M. testâ angustâ, basi cancellatâ; spirâ plicis carinatis; interstitiis sulcis transversis confertis; columellâ 4-plicatâ; gulâ 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 striæ.

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 Linnæan 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 Linnæan 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.