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



low furrows which are narrower than the threads. The generic microscopic fretting can 

 only be made out in peculiarly good light ; but, though very faint, it is certainly present 

 in the furrows. Colour porcellanous, almost hyaline. Spire conical, drawn out, the pro- 

 file lines just a little interrupted by the carinations of the whorls. Apex small, consist- 

 ing of two embryonic whorls, perfectly rounded, not depressed, slightly tumid, hyaline. 

 Whorls 12, of very slow and regular growth, prominent at the keels, but contracted above 

 and below and in the middle. The last is round and prominent on the base, in the centre 

 of which it is impressed in an open umbilical pit. Suture very fine and inconspicuous ; 

 towards the end of the last whorl it is very deeply sunk, from the contraction of the outer 

 lip upon the base. Mouth small, rectangularly triangular, the right angle being at the 

 base of the pillar. Outer lij) advances a good deal at its junction with the base, and 

 is drawn in very much toward the base of the pillar, so that at this point its direction is 

 very nearly at right angles to that of the shell's axis, curving a little, and retreating into 

 the labral sinus ; it here meets the nearly straight line of the patulous and prominent 

 basal lip, which almost forms a sinus at the point of the pillar. Inner Up carried as a 

 thin glaze across the body and round the base of the pillar, so as almost to form an 

 umbilical chink behind it. Pillar perpendicular, straight, with a slight twisted swelling 

 at about one- third of its length ; the edge is very thin and narrow, flat, patulous, and 

 projecting at the side of the pillar as a small ledge. H. 0"35 in. B. - 085, least 0"072. 

 Penultimate whorl, height 0'038. Mouth, height 0-053, breadth 0'055. 



This very beautiful little shell has some features which recall Bittium ; but it has not a distinct 

 canal at the point of the pillar, and it has the labral sinus of Turritella as well as the peculiar micro- 

 scopic spiral fretting of the genus, though this feature is very obsolete. It has, on the other hand, 

 some features of strong individual peculiarity which separate it from any Turritclla known to me. 

 These are its pure hyaline porcellanous colour, its peculiar triangular mouth, and the Vertagus-\ike 

 swelling on the pillar-lip, which, however, is not to be found in the earlier stages of growth, as no 

 trace of it appears in the many broken specimens. In general aspect it somewhat resembles Cerithiopsis 

 Concatenata, Conti (= Cerithiopsis pulchclla, Jeffr., nee C. B. Adams) ; but that species is much more 

 attenuated and ends in a sharp apex, has three strong spiral threads, and is longitudinally ribbed. 



12. Turritella admirabilis, "Watson (PI. XXIX. fig. 5). 



Turritella admirabilis, Watson, Prelim. Report, pt. 6, Journ. Linn. Soc. Lond., vol. xv. p. 227. 



March 7, 1875. Admiralty Islands, north-east of Papua. 16 to 25 fathoms. 



Sliell. — Conical, with a very slight convexity, angulated at the edge of the hollowed 

 base, with a shallow impressed suture ; whorls a little rounded, slopingly shouldered above 

 with a broad open labial sinus. Sculpture : There are very faint sharp curved lines of 

 growth, strongest, as usual, on the base. Spirals — besides the bluntly angulated and 

 slightly swollen basal carina, which appears as a slight projection above the suture at the 



