Cymatium.] GASTROPODA. 309 



Dentition unknown. 



Hob. Throughout New Zealand ; Chatham Islands ; Kermadec 

 Islands : on rocky ledges near and below low- water mark. Australia 

 and Tasmania. 



Fossil in the Miocene and Pliocene. 



Genus 3. ARGOBUCCINUM, Herrmansen, 1846. 



Argobuccinum, Herrmansen, Index Gener. Malac., 1846. Type : Murex 

 argus, Ginel. Bufo, Montfort, 1810 ; not of Laurenti, 1768. 



Shell of medium size, spire short and conic, with spiral cords and 

 more or less distinct axial ribs, sometimes with a nodulous angle 

 on the whorl ; varices continuous or subcontinuous ; aperture rounded, 

 without a posterior sutural channel ; canal short, recurved ; outer 

 lip with an external varix, plicated inside. Columella but little ex- 

 cavated above, distinctly ridged. 



KEY TO SPECIES. 



A. Shell oval, whorls convex, spirally subnodulosely striated, 



varices flattened . . . . . . . . . . argus. 



B. Shell fusiform, whorls shouldered, with a strongly nodose carina, 



varices elevated and rounded . . . . . . . . australasia.- 



1. Argobuccinum argus, Gmelin, 1790. Plate 43, fig. 4. 



Murex argus, Gmel., Syst. Nat., ed. xiii, 3547. Ranella argus, Grnel. ; 

 Lamarck, A.s.V., vii, 151. Triton ranelliformis, King, Zool. Journ.. 

 v, 1832, 347. Ranella vexillum, Sowerby, Conch. Illustr., 1841, pi. 1, 

 f. 3 ; P.Z.S., 1843, 51. R. Kingii, d'Orbigny, Voy. 'Amer. merid., v, 

 1841, 451. Bursa (Apollon) proditor, Frauenfeld, "Novara" Moll., 

 1867, 4, pi. 1, f. 1. Randla argus, Gmel., Man. Conch. (1), iii, 44, pi. 24, 

 f. 61-65. Apollo argus, Gmel., Index, 75. Bursa tumida, Dunker, 

 Nov. Conch. 



Shell ovate, solid, slightly nodulous, varices subcontinuous. Sculp- 

 ture consisting of fine and close spiral striae ; on the spire-whorls 

 there are 4 more prominent spiral ridges, crossed by slightly oblique 

 and numerous radiate riblets, the crossing-points raised into small 

 tubercles ; on the last whorl there are indistinct broad spiral ribs, 

 the whole surface finely spirally striate, and the axial ribs are almost 

 obsolete. Colour : The spiral ridges are reddish - brown, the inter- 

 spaces whitish, sometimes with a brown median thread. Epidermis 

 thin, olivaceous, closely wrinkled, velvety. Spire rather short, conic, 

 about the same height as the aperture. Protoconch small, conical, 

 mostly much corroded. Whorls 8 to 9, the last large, convex ; the 

 varices subcontinuous, flat, inconspicuous ; base slightly excavated 

 at the neck. Suture not deep. Aperture oblique, ovate, channelled 

 above by the teeth of the outer lip, and a strong thick and broad tooth 

 on the parietal wall ; canal short, widely open, slightly recurved. 

 Outer lip expanded, sharp, denticulate towards the base, grooved 

 inside, and with a row of paired teeth. Columella vertical, somewhat 



