Report on the zoological collections made in the Indo-Pacific Ocean ...

MOLLUSC A. 43are not nodulous. The whorls in the latter are not so rounded,decidedly more angular above, much more finelj^ spirally ridged,and bear upon the varices shorter, thicker, and more curvedspines, which are not purple-black tipped, but white, exceptalong the back, where there is a slight ridge of pale brown.M. trihidus has a different apex, more convex whorls, differentcoloration, and much coarser and nodose spiral ridging. Thenumber and position of the spines is seen to be very similar inall three species when closely and carefully compared.13. Murex acanthostephes. (Plate V. fig. B.)Murex (Tribuliis) acanthostephes, Watson, Jqurn. Linn. Soc, Zool.vol. xvi. p. 596.Hah. Arafura Sea, N.W. Australia, in 32-36 fms. ;bottom—mud,sand, and shells.The ' Challenger ' specimen was dredged very near the same spot,in 28 fms.Shell in form and general aspect rather like M. tenuispinn,Lamarck, but with a shorter spire, fewer spines, and a non-canaliculatesuture ; whitish, stained irregularly with light olive-brown.Whorls convex, subangular and carinated above the middle, withtwo or three fine spiral raised lines above the angle upon thesloping and somewhat flattened upper portion, and two or threesimilar lines below the angle. Varices three on a whorl, bearingfive spines upon the convex part and six on the verj- straight beak,with threeor four minute secondary ones reflesed and appressed tothe surface. The uppermost of all, arising from the carina at theupper part of the whorls, is the longest, slightly curved, very erect,and almost parallel with the axis of the shell. The next, No. 2, isminute, jN^o. 3 a little shorter than No. 1 and arcuate, No. 4 muchsmaller, and No. 5 a little smaller than No. 3.The spines on the cauda are straighter than those above, horizontal,or at right angles to the axis, the third, counting fromabove, being a trifle the longest, the rest on each side becomingsuccessively shorter. The body-whorl is transversely lirate throughout,the lira; varying in coarseness, the strongest corresponding tothe longest spines, and being only slightly wavy, whilst some of theintermediary ones are almost subnodular. The three nuclear whorlsarc light brown, glossy, and larger than those of M. tenidspina.The fourth whorl has about eleven short, open, and a little upturnedspines, forming a very pretty coronation at a subcentral angle, andhas no spiral lines above or below it, but a second series of hollowspines below at the suture, smaller than those above. Length37millim. ; diameter 12, exclusive of spines.M. tenuisjjina, a near ally, has longer and more numerous spines,a longer and more pointed spire terminating in a smaller apex, aconspicuously channelled suture, and its sculpture is more pronounced,the spiral ridges being more granular and the lines of