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



species. Gray in Beechey's Voyage, Zool., p. 13G, says that the operculum of Natica mamilla, Linne, 

 is horny. D'Orbigny says nothing whatever of the operculum of his species, and among the very 

 large number of specimens which I got in Madeira not one retained its operculum, nor in dredging 

 did I ever meet with it, which probably indicates its membranaceous character. 



28. Natica [Amauropsis) pterscalpta, v. Martens (PI. XXVIII. fig. 4). 



Natica (Amauropsis) perscatpta, v. Martens, Sitzungsb. Gesellsch. Naturf. Fr. Berlin, February 19, 



1878, p. 25. 



Station 149. January 9, 1874. Lat. 49° 8' S., long. 70° 12' E. Kerguelen. 

 20 fathoms. Volcauic mud. 



Station 149d. January 20, 1874. Lat. 49° 28' S., long. 70° 13' E. Royal Sound, 

 Kerguelen. 28 fathoms. Volcanic mud. 



Habitat. — Kerguelen (v. Martens). 



Professor v. Martens confirmed my identification of this species. He (loc. cit.) observes that in 

 sculpture it recalls Naticina and Sigaretus. He puts it in the Amauropsis group, and but for its 

 shallow suture finds it like Natica islandica, Gm., which it had not suggested to my mind. In the 

 third line of Professor v. Martens' diagnosis, the word ultimo — " lineis . . . circa 20 in an/r. ultimo " 

 should read — pcnultimo. 



29. Natica (Amauropsis) apora, 1 Watson (PI. XXVII. fig. 11). 



• Natica apora, Watson, Prelim. Report, pt. 7, Journ. Linn. Soe. Lond., vol. xv. p. 265. 

 Station 191. September 23, 1874. Lat. 5° 41' S., long. 134° 4' 30" E. Off the 

 Arrou Islands. 800 fathoms. Green mud. Bottom temperature 39°"5. 



Shell. — Conically globose, pointed on the base, with a pointed apex and a very slightly 

 impressed suture ; smooth but not glossy, buff-coloured, with white pillar-lip ; umbilicus 

 quite closed. Sculpture : Longitudinals — close-set, regular, hair-like lines of growth, which 

 above near the suture are gathered into radiating puckers ; these are strongest on the upper 

 whorls. Spirals — there are traces of very slight furrows and obsolete lines, which are 

 somewhat stronger and more regular on the base. Colour: below the ruddyish-yellow 

 epidermis the shell is porcellanous white. Epidermis thin, finely fibrous, persistent. 

 Spire rather high and conical, its outline being hardly broken by the rounding of the 

 whorls and the sinking in of the sutural lines. Apex large, but being eroded, the extreme 

 tip is much effaced. Whorls 5, very little rounded, and, though flattened, not at all 

 constricted below the suture. Suture oblique, scarcely at all impressed, but very slightly 

 channelled. Mouth very oblique from the front backwards, but in its own direction very 

 straight in the line of the shell's axis ; oval, pointed above, and there slightly narrowed, 

 fully rounded below ; a considerable pad fills its upper corner ; it is nearly four-fifths of the 



1 cctooo;, impervious. 



