REPORT ON THE GASTEROPODA. 305 



sinus-area, only marked by the Hues of growth and microscopic spirals ; this band at the 

 top of each whorl gives the scalar appearance to the spire ; below this is a slight raised 

 border, where the longitudinal ribs arise ; and here there is an angulation of the whorl, 

 which is sharp and median on the upper whorls, but is less so on the last. Close below the 

 border of the sinus-area is the first spiral thread, a series of which, fine, rounded, little raised, 

 cover the rest of the shell, rising into small knots on the riblets ; of these threads there 

 are about two on the earlier whorls, four on the penultimate, and about nine or ten on the 

 last, exclusive of those on the snout, of which there are about nine : of these the highest are 

 a little stronger, and the following ones a little more crowded than the others. The whole 

 surface of the shell is microscopically granulated. . Colour dead white. Spire high, narrow, 

 conical, subscalar. Apex consists of four conical embryonic whorls risiug to a minute 

 rounded point a little bent over to one side ; they have a sharp expressed keel and a 

 broad, slightly impressed suture. Whorls 11, rather short, of very regular increase ; they 

 have a sloj)ing, slightly sunken shoulder, below which they have a slight angulation, which 

 is made prominent by the swelling of the riblets and the spiral thread which connects 

 these ; from this point, which lies rather above the middle, the whorls contract gradually 

 downwards till just at the lower suture, where there is a very slight sudden constriction. 

 The last whorl is small, contracting from the keel, with a pinch in toward the point at 

 the base, which is produced into a narrow, slightly elongated, triangular snout. Suture : 

 there is a small narrow depression in the bottom of the open constriction of the whorls. 

 Mouth oblique, narrow, pear-shaped, slightly angulated above, and produced below into a 

 narrow canal. Outer lip thin and sharp, but strengthened by a remote, rather prominent 

 though narrow labral varix : it is only slightly curved on the profile of the shell ; but the 

 lip-edge advances in a very high prominent shoulder, between which and the body lies the 

 narrow, rounded, gutter-like sinus, with a prominent reverted outer edge all round. Inner 

 lip> slightly thickened and feebly tubercled above ; it is thin on the body, but is thicker 

 again on the pillar, on which it advances very directly, with a slightly raised edge, but does 

 not reach the point of the shell, the pillar being cut off with a long, oblique, narrow, barely 

 twisted edge, which advances along the side of the canal beyond the thin callus of the pillar. 

 H. 0-57 in. B. 0-21. Penultimate whorl, height 0-09. Mouth, height '2 5, breadth '08. 



This species considerably resembles Pleurotoma amcena, E. A. Sm., from New Zealand ; but that 

 species has not so scalar a spire, its base and canal are longer, and its apex is blunt. The name of 

 the species is derived from the sculpture. 



36. Pleurotoma (Drillia) sterrha, 1 "Watson (PI. XXI. fig. 3). 



Pleurotoma (Drillia) sterrha, "Watson, Prelim. Report, pt. 9, Journ. Linn. Soc. Lond., vol xv. p. 426. 



September 8, 1874. Flinders Passage, off Cape York, Torres Strait. 7 fathoms. 

 September 8, 1874. Cape York, off Albany Island. 3 to 12 fathoms. 



1 ifEgoo'f, solid. 

 (ZOOL. CHALL. EXr. — PART XLII. — 1885.) Tt 39 



