MOLLTTSCA OP THE ' CHALLENGES ' EXPEDITION. 121 



and minute spiral threads, best seen near the suture ; and there 

 are also indistinct close-set microscopic threads. The base of 

 the pillar is encircled by a minute sharp thread, which is the 

 scar of the siphonal cut. Colour clear, translucent, and glossy 

 white. Spire high, narrow, with slightly convex outlines, which 

 are strongly impressed at the suture. Apex rather abrupt, blunt 

 and rounded ; the extreme point hardly rises above the general 

 curve. Whorls 9, rounded, but a little flattened on the sides, and 

 constricted at the top and bottom of each ; they are of slow and 

 regular increase ; the last is a little larger in proportion than 

 the rest. The base is rounded and a little tumid. Suture, a 

 minute line lying in a deep, open, and rounded depression. 

 Mouth bluntly pointed above, with a rather broad rounded open- 

 ing for the canal at the side of and behind the pillar. Outer lip 

 rounded, slightly incurved above, patulous and projecting on the 

 base, slightly retreating towards the canal, the edge of which is 

 straight all round. Pillar rather short, but not stumpy, scarcely 

 at all twisted, and very little truncated, the end being very much 

 rounded, though there is a slight point on the left side. Inner 

 lip. There is a very thin glaze on the body, which runs straight 

 out on the pillar with a thinnish, but distinct edge. H. 0'133. 

 B. 0-04. Penultimate whorl, height 0-02. Mouth, length 003, 

 breadth 0-019. 



In many of its features this shell is like a minute Terebra, but 

 the form of the whorls rather suggests Gerithium. Unfortunately 

 the canal is slightly chipped. It is much smaller than Cerithi- 

 opsis costulata, Moller ; the ribs, too, are much smaller and the 

 apex is more turbinate. Than Gerithium Naiadis, "Woodward *, 

 this species is much slimmer, and has not the well-marked 

 spirals. 



21. Ceeithittm (Bittium) aedonitjm, n. sp. (ar)Uvios, belong- 

 ing to a Nightingale.) 



St. 135. Oct. 18, 1873. Nightingale Island. Tristao da 

 Cunha Islands. 100-150 fms. 



Shell. — Small, narrow, conical, blunt, with faintly convex out- 

 lines, which are deeply broken at the sutures, rather abruptly 

 truncate at the base, reticulately tubercled, solid, translucent, 

 glossy, white. Sculpture. Longitudinals — there are on the last 



* Dr. Gwyn Jeffreys assures me this species of Woodward is really the same 

 as the Cerithiopsis costulata, Moll. Not having opportunity now of comparing 

 them, I state the fact on his authority. 



LINN. JOUEN. — ZOOLOGY, VOL. XY. 9 



