110 RET. E. BOOG WATSON ON THE 



carination, and here each longitudinal rib projects strongly into 

 a rounded, narrow, longitudinal tubercle ; the base is encircled 

 by a small sharp thread, which is undulated but not tubercled by 

 the longitudinal ribs. Colour translucent white, more ivory than 

 porcellanous. Spire high, narrow, and conical. Apex blunt, in- 

 flated, and projecting beyond the contour-lines of the spire, as if 

 the two embryonic whorls had been squeezed down and spread 

 out in the operation. They are glossy and quite smooth, but 

 with a trace of spiral arrangement in the microscopic texture. 

 Paint traces of the longitudinal ribs appear toward the end of 

 the second whorl, and the spiral threads appear pretty strongly 

 on the third. Whorls 12, of very gradual increase, slightly con- 

 cave on the sides, and below the carina sharply contracted in 

 toward the suture. Suture well marked by the contraction of 

 the whorl above it and the slight angular prominence of the 

 whorl below it. Mouth square and small. Pillar very short, per- 

 pendicular, broad, with a small, blunt, oblique but not reverted 

 point. Inner lip a very thin layer of glaze. H. 022. B. 006. 

 Penultimate whorl 0025. Mouth, length 0*03, breadth 0025. 



The sculpture in this species resembles a good deal C. ambly- 

 terum, W., as they both do 0. metula, Lov. ; but the details of the 

 sculpture are quite different, and the peculiar form of the apex 

 distinguishes it easily from both. The only specimen of this 

 shell was unfortunately broken before it was figured. 



10. Certthium (Bittium) amboynense, n. sp. 



October 6, 1874. Amboyna. 15-20 fms. 



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 pre- 

 ceding 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, 



