750 STUDIES ON AUSTRALIAN MOLLUSCA, xii., 



genus.* These are Murex fiscellum, etc., Conch. Cab., x., 1788, 

 p,242, PL 160, tigs. 1524, 1525, and Miirex undatus, etc., Conch. 

 Cab., xi., 1795, p.l24, P1.192, tigs.1851, 1852. For the former, 

 Gmelin's binomial of Mttrex fiscelhim is available. As Dr. H. 

 Fischer! points out, there can be little doubt of the identity of 

 Murex ricinuloides Quoy & Gaimard, with J/, fiscellum. But 

 Gmelin's binomial of Murex undahis was applied to a species 

 different from that of Chemnitz. Even if the view of Mr. E. A. 

 Smith, that the "undatus" of Chemnitz was legitimate, and could 

 be accepted, it must yield to an earlier Miirex undatus, interposed 

 by Meuschen| eight years before. So that Murex undatus of 

 Chemnitz was left nameless till Broderip called it Murex marga- 

 riticola.% It has also been identified as Murex lie^iardi Crosse.]! 



As Murex margariticola is extremely variable, the present 

 North Australian form was received as but another phase of that 

 polymorphic species. But it appears to differ not only in a more 

 restricted geographical range, but in fewer and bolder ribs, short 

 and broad shape. It may be detined as follow^s : — 



Shell very solid, subumbilicate, biconical, in outline subrhom- 

 boidal . Whorls about seven. Colour externally uniform blackish- 

 brown, aperture edged within by dark purple passing into helio- 

 trope and lilac in the throat. Sculpture : short, thick, widely 

 spaced radial ribs, projecting on the periphery, but vanishing 

 before reaching the base or suture, six on the last whorl. On 

 ascending the spire, these become smaller and more numerous. 

 The entire shell is densely covered by fine spiral threads, on the 

 last whorl forty, and on the penultimate twelve, beset with close 

 minute imbricating scales. Aperture elliptical, subchannelled 

 posteriorly, outer lip denticulated by the spiral sculpture. Four 

 or five small tubercles within the lip. Canal very short, slightly 



*von Martens, Malak. Blatt., xix., 1872, p.242. 

 t Fischer, Journ. de Conch., xlix., 1901, p. 105. 

 X Smith, in Gardiner, Fauna Maldive Arch., ii., 1903, p.609. Meuschen 

 Mus. Gever., 1787, p.330. 



§ Broderip, Proc. Zoo). Soc, 1832, p. 177. Sowerby, Conch. Illustr., 

 Murex, fig.21, 1834. 



II vou Martens, in Mobius, Fauna Mauritius, 1880, p. 232. 



