By some unaccountable oversight, Mr. Dillwyn has very well described this shell, but under the name and supposition of its being the _S. marginatus_ of Linnaeus; though a few pages after he brings all the true synonyms referring to his shell, under a description purporting to be that of _S. minimus_, but which in reality is more applicable to our next species. Why this writer should doubt the correctness of Gmelin, Chemnitz, &c. respecting the true _S. marginatus_ of Linnaeus, does not appear, particularly as he has substituted for it a well known species. I have little doubt myself they all mean one and the same shell, which is nothing more than a scarce variety of _S. accinctus_, now before me, with which Linnaeus's original description pretty well agrees. * * * * * STROMBUS variabilis. _Variable Strombus--upper figure._ _S. testa nodose plicata, spira striis nullis; labio interiore simplice, exteriore reflecto, intra laevi, supra leviter lobato._ Shell with nodulous plaits, the spire not striated. Inner lip simple. Outer lip reflected, smooth within, and slightly lobed above. * * * * * Shell two inches and a quarter long, the spire occupying little more than half an inch. The ground colour generally is white with numerous undulated short lines of a darker colour, sometimes crossed by four or five obsolete whitish bands: it approaches very near _S. minimus_, but is easily distinguished by being in general much larger, by having the inner lip not at all thickened above, the outer lip very slightly lobed, and only advancing on the first volution of the spire: it varies, however, amazingly in colour. There is a small variety, having a brown spot beneath, from India; and others (labelled from the So. Seas) in the Banksian collection, also small, are purplish-brown, with three or four well-defined bands of white: the aperture is always pure white. * * * * * Pl. 11 [Illustration] DRUSILLA Horsfieldii. * * * * * GENERIC CHARACTER. _Antennae mediocres, clava producta, gracili, cylindracea. Palpi breves, compressissimi, obtusi, remoti, linguam non attingentes; lateribus utrisque hirsutissimis, articulos obtegentibus. Abdomen (in maribus) 7-articulatum: 1mo longissimo, ultimo simplici, truncato, supra integro, subtus unco incurvato, valvis nullis. Alae anticae (in maribus) basi postica dilatatae, fasciculum in alas posticas obtegentes._ (OBS. _Alae integerrimae, subdiaphanae, posticae magnae, orbiculares. Pedes antici spurii; antennarum articuli basales ad apicem incrassati._) Typus Genericus _Papilio Jairus_. Fabr.