492 MOLLUSCA OF MAST HEAD REEF, QUEENSLAND, II., 



dull brick-red, except a brilliant cadmium-orange ring round the 

 aperture. Sculpture: the earlier whorls are strongly radiately 

 plicate below the sutures; periphery armed with short, broad, 

 downwardly directed spines becoming obsolete towards the 

 aperture; on the penultimate whorl they number sixteen. Close 

 spiral cords densely beset with imbricating scales cover the surface 

 of the shell; above there are ten cords carrying more distant 

 hooded scales obliquely connected with those above and below. 

 On the base there are also ten cords with more crowded scales. 

 Base flattened. Aperture very oblique, subcircular, within and 

 upon the columella pearly; a narrow inner margin to the lip 

 continuous with an axial callus pad is bright cadmium-orange. 

 Operculum pale orange, oblong, nucleus subtermiual, hollow 

 medially between two ribs, one of which rises proximally into a 

 heavy callus mound. Height 87 mm.; major diam. 92 mm.; 

 minor diam 80 mm. 



A single living and adult specimen from 20 fathoms a few 

 miles south of Mast Head. This, the prize of the Expedition, 

 and probably the handsomest shell discovered anywhere during 

 the year, was captured in the last haul of the dredge. In size 

 and general appearance it is comparable to A. sulcatum Marty n, 

 from New Zealand, and may be classed as a second member of 

 the subgenus Cookia. The subscalar whorls, peripheral thorns 

 and orange mouth of A . aureolum distinguish it. I am indebted 

 to my friend and colleague, Mr. A. R. McCulloch, for an excellent 

 figure of this splendid shell. 



Cyclostrejnia cubitale, n.sp. 



(Plate xvi., fig.8.) 



Shell minute, thin, translucent, conical, perforate. Colour 

 white. Whorls four, the first two rounded, smooth. Sculpture: 

 a dozen prominent, distant, thin radial ribs descend the last two 

 whorls perpendicularly, broadening at the periphery; these there 

 produce a marked angle to the contour of the shell. Spiral 

 threads lattice the interspaces and denticulate the edges of the 

 ribs. Aperture round, adherent anteriorly to the body-whorl for 



