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



are much less barred longitudinally, the ribs on the regular whorls are sparser and weaker, the 

 inferior spiral lies much lower on the whorl and forms much less of a keel, and the base is not 

 contracted as in that species. The only specimen of this shell was unfortunately broken before it was 

 figured. 



7. Bittium amboynense, Watson (PI. XL. fig. 5). 



Cerithnim {Bittium) amboynense, Watson, Prelim. Report, Journ. Linn. Soc Lond., vol. xv. p. 110, 



sp. 10. 



October 6, 1874. Amboyna. 15 to 20 fathoms. 



Shell. — Small, narrow, conical, with convex outline, a narrow, contracted and bluntly 

 conical base, solid, opaque, dull, light brown. Sculpture : Longitudinals — there are on 

 the last whorl about 20 broad, shallow depressions, parted by longitudinal rows of small 

 tubercles, which, toward the mouth, tend to crowd out the depressions. These rows 

 preserve no relation to each other in adjoining whorls. There is about the middle of the 

 whorl a broad, feeble varix, which includes several of these rows of tubercles ; there 

 are besides many irregular lines of growth. Spirals — there are on the last three whorls 

 four, and on all the preceding whorls three spiral threads, which are beset with small, 

 low, round tubercles, which become smaller toward the mouth. Above the suture another 

 very small spiral appears ; it lies just within the contraction of the base, and has no 

 tubercles. "Within this, on the base and close to it, is another and stronger spiral. A 

 broad, shallow, but well-defined furrow lies within this, having a minute spiral in the 

 bottom of it. The pillar rises within this furrow, encircled by a rather strongish spiral 

 thread, and three other finer spirals twine round it. Only on the base is there the faintest 

 trace of excessively minute microscopic spirals. Colour pale yellowish brown, quite uniform 

 throughout. Spire high and narrow, with convex contour-lines, which are strongly 

 impressed at the suture. In the upper part of the spire the whorls are a little scalar. 

 Apex broken. WJwrls 9, flat, of very gradual increase. Suture impressed. Mouth 

 square. Outer lip broken. Pillar straight, short, and broad. Inner lip formed by a 

 thick layer of glaze, which presents a narrow edge on the pillar. H. 0*14 in. B. 0'05. 

 Penultimate whorl, height 0'025. Mouth, height 0'03, breadth 0"02. 



This species very much resembles Bittium reticulatum (Da Costa), but there is appreciable 

 difference in its contour-lines, which are much more curved, and the upper whorls are scalar, while 

 in the young of that species, with the same number of whorls, the contour-lines are straight and 

 the outline perfectly conical. In this, too, the base is more contracted and hollower than in that. 

 The apex is unfortunately broken ; but the basal part of the embryonic shell is broader, less oblique, 

 and has not the characteristic fine spiral threads which encircle the base of the second and third 

 whorls in that species. 



