MOLLUSCA OF THE * CHALLENGER ' EXPEDITION. 429 



upper whorls are cylindrical below the shoulder ; but the body- 

 whorl contracts almost at once, and on the base does so very rapidly 

 and with very straight lines, so that this whorl is very small. 

 Suture very small and faint. Mouth small, narrow, elongatedly 

 oval. Outer lip broken : the sinus lies close up to the top of the 

 whorl, and is small, round, and deep. Inner lip : there is a small 

 thick pad above ; but below it is thin, narrow, slightly turned 

 back on the straight pillar ; but toward the point it is turned 

 again forward on the edge of the blunt and hardly twisted lip. 

 H. 0-63. B. 0-26. Penultimate whorl, height 0*13. Mouth, 

 height 0-25, breadth Oil. 



In form, though broader, this species a good deal resembles 

 P. Barkliensis, H. Ad. ; but in all details it is unlike. In form it 

 slightly resembles P. Jwrpularia, Couth.*, but has the base less 

 elongated and more pinched in, the whorls more cylindrical, and 

 the w r hole shell more spindle-shaped, with coarser, stronger, and 

 fewer spiral threads, forming tubercles on the ribs. It is not 

 unlike P.granularis, E, Sm., B. M., but has narrower, sharper, and 

 more widely parted ribs and a more conical spire. 



30. Plettrotoma (Clavus) marmarina, n. sp. (fxapfjiapivos, 

 gleaming like marble.) 



St. 122. Sept. 10, 1873. Lat. 9° 5' S., long. 31° 50' W. Oft" 

 Pernambuco. 350 fms. Mud. 



Shell. — Biconical, with a high pointed spire, a short lopsided 

 base, and a very short snout, ribbed, barely tubercled, with 

 spiral furrows, and a compressed band below the scarcely im- 

 pressed suture. Sculpture. Longitudinals — there are on the last 

 wborl 15 rather narrow, spread-out, rounded, scarcely oblique 

 direct ribs, which begin at the upper suture and extend to the 

 base, but not to the snout ; near the top they are cut by a spiral 

 furrow, so that the upper part of them forms a series of small 

 rounded tubercles just below the suture ; below the spiral furrow 

 the ribs are slightly swoln into knots ; the ribs are parted by 

 wider shallow furrows : these ribs and furrows run pretty regu- 

 larly down the spire ; but there are fewer of them on the earlier 

 whorls. The whole surface is further scored by almost micro- 

 scopic regular hair-like lines of growth, which are specially sharp 

 in the sinus-area. Spirals — there is a furrow near the top of the 



* I copy this note as I made it in the Berne Museum ; but I cannot at pre- 

 sent ascertain what species of Couthouy this is. 



LINN. JOTTRN. — ZOOLOGY, VOL. XV. 33 



