HOLLUSCA OF THE ' CHALLENGER ' EXPEDITION. 119 



the shell is microscopically scored with irregular lines of growth 

 and fine spiral scratches. Colour dark ruddy brown, uniform all 

 over. Spire high, narrow, pointed, with straight but slightly an- 

 gulated contour lines. The first eight whorls expanding regularly, 

 so as to form a minute cone, while the last four expand more 

 slowly, so as to give more of a cylindrical shape. Apex small, 

 blunt, rounded, slightly oblique, and a little immersed. Whorls 

 13, flat, except the last, which is slightly convex, with a somewhat 

 flat but conical base. Suture in the bottom of a deep furrow is 

 concealed by a projection of the inferior whorl. Mouth oval, with 

 a small rounded sinus at the upper outer corner, and a largish 

 and deepish canal running in behind the pillar. Outer lip not 

 expanded, deeply corrugated by the ends of the spirals, with a 

 deep V-shaped fissure forming the canal. Pillar straight, not 

 short, pretty strong, with a rounded, narrow, twisted edge, and a 

 small but not sharp point, which is very slightly reverted. Inner 

 lip little more than a film on the body and pillar. H. 0'27. B. 

 0-064. Penultimate whorl 0-031. Mouth, length 0-042, breadth 

 0-028. 



19. Cerithium (Bittium) abrtjt-tum, n. sp. 



St. 75. July 2, 1873. Lat. 38° 38' N., long. 28° 28' 30" W. 

 Fayal, Azores. 450-500 fms. Sand. 



Shell. — Small, narrow, conical, blunt, in general form very like 

 a decollated Cerithiopsis rnetaxa, solid, translucent, white. Sculp- 

 ture. Longitudinals — there are on the last whorl about thirteen, 

 on the earlier, fewer longitudinal ribs, which are low and narrow, 

 and are parted by flat and broader furrows. They come down 

 the spire, from whorl to whorl, with a strong sinistral twist. The 

 embryonic whorls have ten or twelve small ribs. Spirals — ex- 

 cept on the first two whorls there are on each whorl four narrow, 

 rounded, prominent spiral threads, which rise, as they cross the 

 longitudinals, into pointed high tubercles. The furrows which 

 part them (except that between the third and the fourth) are 

 narrower than the spirals. The highest of these spirals is the 

 weakest and least prominent, being pinched in by the superior 

 contraction of the whorl into the suture. Close above this highest 

 spiral runs the suture, The base of each whorl is roundly but 

 rather abruptly contracted, so that the sutural furrow has its upper- 

 side abruptly, its underside gradually, declining. The base, which 

 is oblique, concave, and contracted, has a strong plain spiral thread 

 round its edge, and a very minute thread encircling the base of 



