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



except towards the point of the base. Spirals — at the top of each whorl is a minute 

 projecting band beset by very small conical nodules corresponding to the longitudinal 

 ribs. About one-third down the whorls there is an angulation accentuated by the rib- 

 nodules ; halfway between this and the inferior suture a minute sharpish thread appears 

 on the penultimate whorl, while other four, similar and ecpially parted, appear on the 

 base ; all these five threads rise on the ribs into minute sharpish nodules. On the snout 

 there are neither ribs nor spiral threads, only obsolete lines of growth. Colour pale 

 greyish-white. Spire conically cylindrical, the last whorl being very small and the earlier 

 ones broad ; the profile-lines are interrupted by the nodulous angulation and the impressed 

 suture. Apex consists of 1^ smooth, globularly rounded whorls, the extreme point of 

 which has the slightest possible prominence. Whorls 7\ to 8, of very slow increase, short, 

 the last scarcely more tumid than the rest, with a contracted conical base and a shortish 

 snout ; they are angularly convex, with a slight contraction into the suture both at the 

 top and bottom of each whorl. Suture : there is a minute angular impression at the line 

 of suture, which is marginated below, and is made yet more distinct by the contraction of 

 the whorls above and below. Mouth pear-shaped, small, with a slight angulation above 

 and a rather wide and open canal below. Outer Up forms a regular curve, steeper above, 

 and more drawn out below towards the point of the shell ; on leaving the body it retreats, 

 at once and very much ; after forming a shallow, open, rounded sinus, it advances as a small 

 low-shouldered pinion, retreating along the edge of the canal to the point of the shell. 

 Inner lip narrow, slightly sunken, so that the surface of the shell projects a little at the 

 edge of it ; its line across the body is straight, being neither convex nor concave. The 

 pillar is narrow, strong, and very short, being obliquely cut off early, with an angularly 

 rounded, slightly twisted edge, and a point truncated backwards. H. 0*3 in. B. O'll. 

 Penultimate whorl, height 0-05. Mouth, height 0-1, breadth 0-07. 



This is another of that curious group which have a tendency to a cylindrical form, a long spire, 

 many short whorls, a broad apex, and a short base. 



I have with some hesitation united to this species as a var. platia the specimens from Station 

 122. As the name indicates, they are broader in proportion to height; they are also less cylindrical, 

 the embryonic whorls in particular, the tip being rather smaller and the basal part of the apex 

 broader ; the threads on the base of the shell are weaker. On the other hand, the whole form of 

 the whorls and the details of sculpture are identical. In these circumstances it is probably wiser to 

 unite them all in one species, attributing the differences partly to habitat and partly to the specimens 

 of the variety being not fully grown. 



