REPORT ON THE GASTEROPODA. 323 



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

 Royal Sound. 28 fathoms. Volcanic mud. 



Habitat. — Kerguelen in 120 fathoms, on a rocky bottom (Studer). 



Professor v. Martens, whose admirable figure is reproduced here, has confirmed my identi- 

 fication of the species and also of a variety of it obtained by the Challenger. In both of these, 

 particularly on the base, a few faint and irregular spiral threads exist besides those referred to by 

 him in the sinus-area ; though somewhat faint, they are also to be found on his specimens. One 

 of the spirals on the base forms a very slight angulation or keel. The operculum, which Professor 

 v. Martens does not mention, like that of many of these frigid Pleurotomas, is pale yellow, thin, oval, 

 slightly pointed below, where, on the outside face, as often, is the minute slightly elevated nucleus in 

 shape like a finger-nail ; from this the numerous fine lines of growth returning upon themselves form 

 oval loops. These lines, as usual, are a little stronger and more crowded on the pillar edge. 



53. Pleurotoina (Spirotropis) aganactica, 1 n. sp. (PI. XXVI. fig. 8). 



Station 133. October 11, 1873. Lat. 35° 41' S., long. 20° 55' W. Mid-Atlantic. 

 1900 fathoms. Globigerina ooze. Bottom temperature 35°*4. 



Shell. — Thin, long, narrow, white, feebly double - keeled, spiralled, with a short 

 rounded base, broad, short, lop-sided snout, high conical spire, and slightly angularly 

 impressed suture. Sculpture: Longitudinals — nothing but lines of growth in slight 

 puckerings. Spirals — with the exception of the subsutural area, the surface is scored 

 with slight broadish threads with feeble furrows. Two of the threads stronger than the 

 rest, and about -^ in. apart, lie at the periphery, and form a blunt double-keel on the 

 whorls ; under the lower one and within the contraction of the base is another thread 

 not quite so strong as either of these two. Colour white, but the shell is very much 

 weathered. Spire tall and conical. Apex : all the upper whorls of the spire are gone. 

 Whorls : only 3^ remain ; the last is small, but is a little tumid, with a short rounded 

 base and a very short lop-sided snout. Suture rather oblique, well marked by the 

 angulation of the whorls and by a slight contraction of the whorl just above. Mouth 

 elongately oval, rather small. Outer lip thin, well arched ; the sinus is strong, but very 

 open ; it lies near the suture with a triangular shelf above it. Inner lip spreads 

 with a broad thin glaze on the body ; its line is concave ; the pillar is short, slightly 

 oblique, and is shortly cut off, with a slight twist at the point. H. 1 in. B. 0'48. Pen- 

 ultimate whorl, height - 22. Breadth of first remaining whorl, 0'18. Mouth, height 

 0-48, breadth 0'29. 



The solitary specimen of this species has been grievously fretted by an Actinia, and is indeed 

 but a fragment, not less than 5 or 6 whorls having perished, and the surface of the shell being much 

 ■destroyed. 



1 ayavaxrixos, easily fretted, as weak and thin. 



