REPORT ON THE GASTEROPODA. 611 



mouth. Sculpture: none but very faint lines of growth. Colour slightly glossy horn)-, 

 paling to translucent white toward the mouth. Spire conical. Apex very bluntly 

 rounded. }Vhorls 4 ; of rapid but regular increase, convex. Suture very slightly im- 

 pressed, barely oblique. Mouth small, almost round. Outer lip thin, equally curved all 

 round. Inner lip distinct and defined across the body ; direct and narrow on the pillar, 

 with a very feeble furrow, but no chink behind it. H. 0'042 in. B. 0-029. Mouth, 

 height 0-019, breadth -01 8. 



This species differs from fiissoa edwardiensis in that it is very much smaller, is more elongated in 

 form, and has no umbilical chink. 



45. Rissoa (Setia) triangularis, n. sp. (PI. XLVL fig. 2). 



Station 344. April 3, 1876. Lat. 7° 54' 20" S., long. 14° 28' 20" W. Ascension 

 Island. 420 fathoms. Volcanic sand. 



Shell. — Small, triangular, almost equilaterally so, umbilicate, white, with a flattish tip, 

 convex whorls, a slightly impressed suture, a flat oblique rounded base, an unvarixed lip, 

 and a round mouth. Sculpture: none, but fine lines of growth, and a carina round the 

 umbilicus. Colour white. Spire very short, conical, with outlines very slightly convex. 

 Apex small, somewhat abruptly flattened, with the extreme tip very bluntly prominent. 

 WJwrls 4tj, of very regular increase, convex, slightly tumid. Suture impressed, scarcely 

 oblique. Mouth round, but slightly pointed above. Outer lip thin, well curved, and 

 slightly patulous all round. Inner lip thin and sharp, continuous on the body, a little 

 expanded and arched on the pillar, with a well-marked and margined umbilicus behind it. 

 H. 0-041 in. B. 0-037. Mouth, height 0-021, breadth 0-02. 



This species somewhat resembles Trochus minutulus, Jeffr., but that shell has not a continuous 

 inner lip ; the spire there is higher, the penultimate whorl is broader, more conical, less rounded, the 

 body-whorl is narrower, the base rounder, and the umbilicus is not carinated. 



G. Moutli separated from body-whorl (Scrobs). 



46. Rissoa (Scrobs) scrobiculator, n. sp. (PI. XLVL fig. 4). 

 April 17-18, 1874. Port Jackson, Sydney. 2 to 10 fathoms. 



Shell. — Small, rather strong, elongately obovate, brdliant, crimson-chestnut, with a 

 narrow spire, few laterally flattened whorls, a small rounded tip, a large horizontally set 

 mouth occupying the whole base, and a furrowed ' double lip. Sculpture ; there are many 

 very oblique hair-like lines of growth, and there are, especially on the last whorl, close-set 



1 Hence the name. 



