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



Habitat.— China (Shuttleworth Collection, Bern Museum), Philippines (Reeve), Pon- 

 dicherry (Kiener), Timor (AVeinkauff), Red Sea (Jickeli). 



Deshayes (loc. cit. supra) rejects Kiener's identification (see the Iconographie, loc. cit. supra) of 

 this species altogether, apparently on very good grounds. Weinkauff (in Conch. Cab., loc. cit. supra) 

 seems satisfied with Kiener's figure as really representing Lamarck's species, but he himself apparently 

 figures some other species. As to Reeve's figure (loc. cit.), it is impossible to say what he meant to 

 represent, and Tryon merely copies his figure. I have simply quoted these different authors for what 

 they may be worth. 



6. Pleurotoma ischna, 1 Watson (PL XXII. fig. 2). 



Pleurotoma ischna, Watson, Prelim. Report, pt. 8, Journ. Linn. Soc. Lond., vol. xv. p. 403. 



Station 169. July 10, 1874. Lat. 37° 34' S., long. 179° 22' E. N.E. from New 

 Zealand. 700 fathoms. Blue mud. Bottom temperature 40°. 



Shell. — High, narrow, conical, blunt, with, a contracted base and longish snout, little 

 sculpture, strongish, yellowish grey, porcellanous. Sculpture : Longitudinals — there are 

 only strongish unequal lines of growth, 2 which rise into small tubercles, especially on the 

 upper whorls ; between the stronger lines the surface of the shell is delicately fretted 

 with other very minute sharp lines. Spirals — the whorls are faintly keeled above the 

 middle by a spiral thread, which is a little stronger and more prominent than any of the 

 others. Close above the suture is another almost as strong, and which also slightly 

 carinates the whorls ; half-way between these is a finer thread, which tends to split into 

 two very fine threads ; at the suture, but visible beyond the mouth, is another thread, 

 which here defines the base. The longitudinals rise into very small tubercles as they 

 cross the spirals ; but this feature is much stronger on the upper whorls, which are reti- 

 culated ; on the last whorl it is feeble. Between the keel and the superior suture lie three 

 very fine, equally parted, threads. On the base and snout are about twelve pretty equal 

 fine threads. Colo ur a faintly yellowish grey. Epidermis extremely thin, smooth. Spire 

 conical, with an almost unbroken profile, the whorls being scarcely convex. Apex — there 

 are barely two embryonic whorls, smooth, globose, not flattened down at the tip, which, 

 however, is slightly immersed. Whorls 7 in all, feebly keeled with a just perceptibly 

 concave line from the suture to the keel, and from the keel to the suture below. Just 

 above the suture there is a slight contraction, which forms a faint superior margination. 

 The last whorl is very slightly swollen ; the base is rather rapidly contracted, and is 

 drawn out into a rather long, straight, but not narrow snout. Suture distinct, impressed. 

 Mouth almost club-shaped, being pointedly oval above, with a longish rather sinuous 

 canal below. Outer lip forms a regular curve, till at the canal it becomes flattened and 



1 'ns-/fih;, lean. 



2 These are much too strong, too remote, and too straight in the figure, which is besides too broad and too 

 angular, and does not sufficiently show the furrowed suture. 



