302 THE VOYAGE OF H.M.S. CHALLENGER. 



Shell.— Fusiform, biconical, very slightly and bluntly angulated, with a scarcely convex 

 base, elongated into a largish, slightly reverted, rather equal-sided snout. Sculpture: 

 Longitudinals — there are no ribs ; but the close-set, hair-like lines of growth, at nearly 

 regular intervals over the whole surface, rise into thread-like folds which score the shell 

 rather markedly. Spirals — near the bottom of each whorl there is a slight keel on the 

 line of the old sinus-scars ; it includes two bluntly rounded, close-set threads, which are 

 crenulated by a series of small squarish tubercles arranged in pairs, one on each thread 

 and placed one above the other, thus forming short little bars ; they are parted by furrows 

 broader than themselves. There are about forty of these bars on the last whorl, becoming 

 more irregular towards the mouth : on the penultimate whorl there are about fifty ; but 

 they again diminish in number on the upper whorls. Answering to these is another 

 double row at the top of the whorls immediately below the suture ; only in these the under 

 thread is more prominent, and has rounded tubercles, while the upper thread is scored by 

 longitudinally narrow sharpish little bars ; between these infra-sutural threads and the 

 carinal threads the slightly concave surface is scored by four finer threads set with little 

 white nodules. Of these, the second thread from above is the strongest, and its nodules 

 are rhomboidal. Below the keel the whole surface is scored by distinct rounded threads, 

 which rise into small nodules where crossed by the stronger lines of growth ; the intervals 

 between these are more than double the width of the threads ; they rather increase in 

 distinctness forwards ; two groups of three and then one by itself have finer threads, like 

 shadows, in the intervals below them. Colour porcellanous white, with a buff apex and a 

 faint tinge of suffused buff on the body, especially in the sinus-scar and within the mouth ; 

 the nodules stand out pure white. Spire high and perfectly conical. Apex l\ small, 

 rounded, globular, brownish-buff coloured, embryonic whorls, of which the first is a good 

 deal turned up on one side. Whorls 10, slightly keeled and banded, conical, broad, short 

 and of very regular increase ; the last rather large, long, scarcely tumid on the base, 

 gradually produced into a large, conical, rather equal-sided snout, which is obliquely cut 

 off from the point of the pillar backwards towards the outer lip, and which has a slight 

 twist toward the right. Suture slightly canaliculated, from the thickening of the infra- 

 sutural collar, behind which it is a little sharply cut in. Mouth long and narrow, sharply 

 angulated above, scarcely contracted below, and with hardly any canal in front ; there is 

 a slight tinge of buff within. Outer lip very sharp and thin and a little contracted, except 

 just toward the end of the canal, where it becomes slightly patulous ; its course is an 

 angulated curve, steep above and long-drawn below. On leaving the body, it retreats 

 very slightly and almost straight to the rather distant, bluntly rounded, large, open, and 

 rectangular sinus ; from this point its edge forms an almost semicircular curve to the point 

 of the shell. Inner Up is hollowed rather deeply into the substance of the shell, which 

 forms a raised edge outside of it ; it is narrow on the body, rather broad on the pillar. 

 The line across the body and down the pillar is very little concave. The pillar is long 



