REPORT ON THE GASTEROPODA. 295 



of tubercles, but especially the upper, are very sharp and distinct on the earlier whorls, 

 but lose individuality further down the spire. From the keel downwards the whorls are 

 scored with flat rounded threads. Colour pale buff, deepening somewhat up the spire, 

 glossy. Spire high, conical, the profile-lines only slightly interrupted by the prominence 

 of the tubercled keel. Apex : the two embryonic whorls are smooth, small, conical, with 

 a small rounded tip slightly flattened down on one side. Wliorls 9 (remaining), short, 

 of very regular increase, slightly concave in the shoulder, sharply angulated at the keel, 

 and contracted into the suture below. The whole base and pillar have been broken 

 away. Suture rather oblique, defined by the slight contraction of the superior and inferior 

 whorls. Mouth is broken, but the sinus is broad, rounded, and deep, in consequence of 

 the long forward sweep of the pinion-like edge of the outer lip. 



This species exists only in one fragment ; but its beauty and its strongly marked features make 

 it worth notice. It extraordinarily resembles Pleurotoma dimidiata, Brocchi, but is a broader shell, 

 with a coarser stumpier apex of fewer embryonic whorls, has no spirals above the keel, while those 

 below are finer; the suture is much less sunken between the keels, and there is a substantial 

 coronet of tubercles. Pleurotoma powerii, Calcara (a specimen of which I owe to the kindness of 

 the Abbe Brugnone), has the upper part of the whorls above the keel free of spirals, and the apex is 

 more like that of Pleurotoma hemimeres, but in form it is still slimmer than Pleurotoma dimidiata, 

 and its sculpture otherwise is even less like. 



23. Pleurotoma (Surcula) anteridion, Watson (PL XIX. fig. 6). 



Pleurotoma (Surcula) anteridion, Watson, Prelim. Report, pt. 8, Journ. Linn. Soe. Lond., vol. xv. 



p. 399. 



Station 142. December 18, 1873. Lat. 35° 4' S., long. 18° 37' E. Off the Cape of 

 Good Hope. 150 fathoms. Green sand. Bottom temperature 47°. 



Shell. — High, narrow, biconically fusiform, subscalar, with angularly convex and 

 longitudinally-ribbed whorls, thin, tawny. Sculpture : Longitudinals — a little way below 

 the suture is an angulation where narrow, raised, oblique ribs begin ; these slope from 

 right to left ; they extend to the suture, but not to the base, where they die out more 

 gradually than they arose ; they are parted by rounded hollows, which are wider than the 

 ribs. There are about nineteen of these ribs and hollows on the last whorl, but fewer on 

 each preceding one ; besides these, there are very many fine hair-like flexuous lines of growth. 

 Spirals — the shoulder below the suture (the sinus-area) has a few faint regular scratch-like 

 lines ; on the ribbed area these are stronger. On the base the interstices become somewhat 

 narrower and more convex, till on the snout they rise into strongish threads, which at the 

 very point again become weaker. Colour a light tawny, paler on the snout, and white on 

 the pillar. Spire high, conical, and slopingly subscalar. Apex broken. Whorls probably 

 10, rather short, with a straight somewhat drooping shoulder, convex, and appearing 



