GENERIC CHARACTER.--See Pl. 23. * * * * * SPECIFIC CHARACTER. _M. testa inverse pyriformi, fusca; sulcis transversis intus punctatis; anfractibus superne obsolete plicatis, fasciaque alba ornatis; labio exteriore tenui, margine crenata; columella 4-plicata; basi alba, truncata._ Shell inversely pear-shaped, brown, with transverse sulcated grooves, punctured within; volutions above obsoletely plaited and banded with white; outer-lip thin, margin crenated; pillar four-plaited; base white, truncated. * * * * * We have had much difficulty in the investigation of this species: for its characters cannot be reconciled with any of those contained in Lamarck's Monograph of the genus in the _Annales du Museum_. With regard to the unnamed figures in the old authors, it bears the closest resemblance to that of _Gualtieri_, tab. 32. G, which Lamarck quotes for his _M. crocata_; but then his description is not at all applicable to our shell; and Mr. Dillwyn's synonyms of the Linnean _V. nodulosa_ (where he has also included _M. crocata_), we are satisfied comprises two or even three distinct shells. This was named by Dr. Solander from the specimen in Mr. G. Humphrys's collection here figured: it is exceedingly rare, and its locality unknown. In form it resembles a _Buccinum_; the transverse grooves are broad, strongly defined, and have large and deep excavated dots within them; the upper part of each whorl has an appearance of irregular plaits, which makes the suture uneven, and takes off something from the smoothness of the lower part of the whorls, but the shell is in no way granulated. * * * * * MITRA ferruginea. _Thick-lipped Mitre._ * * * * * SPECIFIC CHARACTER. _M. testa nubila, maculisque ferrugineis interstincta; costis transversis, elevatis; labio exteriore crasso, obtuse crenato; columella 4-plicata._ Shell clouded and spotted with ferrugineous, with transverse elevated ribs; outer lip thick, obtusely crenated; pillar four-plaited. M. ferruginea. _Lam. Ann. du Mus. vol._ 17. _p._ 200. _Young._ Vol. vitulina. _Dill._ 553.--_Martini_ 4. 149. 1380 & 1. _Variety_ more elongated. Vol. abbatis. _Dill._ 557. _Chemnitz_ 11. _t._ 177. 1709 & 10. * * * * *