MOLLUSCA OF TIIE C CHALLENGER ' EXPEDITION. 251 



Bermudas. Bottom temperature 38°*2. 1000-1075 fms. Grey- 

 ooze. 



Shell. — Small, high, conical, tapering a little abruptly to a fine 

 point, with rounded whorls and base, longitudinally and spirally 

 ribbed, Sculpture. Longitudinals — in the last two whorls there 

 are 14-15 rather narrow and sharpish ribs ; they slowly increase 

 in number as one follows them up the spire ; on the two subem- 

 bryonic whorls they suddenly increase to about 30. At the top 

 of each whorl they are small, sharp, and strongly convex towards 

 the left; lower down on the whorl they are straight; they are 

 parted by flattish furrows two to three times their breadth ; on 

 the last whorl they are oblique and somewhat irregular in form 

 and arrangement, on the base they disappear. Besides these the 

 whole surface of ribs and furrows is scored with microscopic 

 rounded and very distinct threads. Spirals — on each whorl there 

 are five small rounded spiral threads ; the highest and strongest 

 lies at about two fifths of the whorl's breadth below the suture, 

 and forms an angular shoulder on the whorl, whose chief projec- 

 tion is at this point ; the rest are pretty equally distributed on 

 the whorl; the fourth is weaker than the two above it, and the 

 fifth, which is still smaller, lies exactly at the suture. All of 

 these, but especially the first, rise into little sharpish knots as 

 they cross the ribs ; on the subembryonic whorls they disappear. 

 Colour glossy, translucent white. Spire high and conical, but 

 the upper fourth of the shell tapers a little abruptly to a very 

 fine point ; its outlines are broken by the strong sutural con- 

 striction. Apex : the extreme tip is broken. Whorls : there are 

 eight below the missing embryonic one, of rapid growth in height 

 and breadth ; they have a sloping shoulder below the suture 

 down to their point of chief breadth at the carination ; from this 

 to the third spiral, where is also a slight carination, they have a 

 straightish outline ; below this they contract on an equable curve 

 into the suture ; the base is roundly conical. Suture : its place 

 is strongly defined by the constriction at the top and bottom of 

 each whorl and by the lowest spiral, which forms its upper edge, 

 but it is much interrupted and obscured by the curved points of 

 the ribs, which bend round convergingly into it. Mouth gib- 

 bously oval, being almost semicircular to the right and obliquely 

 straight on the body and pillar. Outer lip thin, advancing 

 strongly at its junction with the body, from which point it re- 

 treats with a rapid open curve, which produces the sickle-like 



