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



Whorls 5, convexly conical on the sides, of regular somewhat rapid increase. Suture 

 very slightly impressed, little oblique. Mouth largish, oval, barely pointed above. Outer 

 lip sharp, well rounded, patulous on the base, strengthened by a broadish varix. Inner lip 

 strongish and defined on the body, curved, with a sharp very slightly prominent edge on 

 the pillar, where there is just barely a furrow behind it. H. 0"06 in. B. 0'4. Mouth, 

 length 0-028, breadth 0'023. 



This species is like Bissoa philomclce, Wats., but is stronger in texture, has a narrower spire, a 

 smaller penultimate whorl, a varixed lip, a spiralled base, and no umbilical chink. 



43. Rissoa (Setia) edwardiensis, n. sp. (PI. XLV. fig. 11). 



Station 145. December 27, 1873. Lat. 46° 43' S., long. 38° 4' 30" E. Off Prince 

 Edward Island. 50 to 150 fathoms. Volcanic sand. 



Shell. — Strongish, conically globose, ruddily horny, smooth, with a blunt rounded tip, 

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

 and an oval mouth. Sculpture : none, except very faint lines of growth. Colour dull, 

 ruddy, horny, paling to white at the mouth. Spire bluntly conical, with slightly convex 

 profile-lines. Apex very bluntly rounded. Whorls 4^, convex, the last tumid. Suture 

 slightly impressed, barely oblique. Mouth largish, oval, barely angulated above, where 

 the outer lip springs from the body at a right angle. Outer lip thin, equally curved all 

 round, and slightly patulous. Inner lip extremely thin on the body, expanded on the 

 pillar, so as to obscure the furrow and umbilical chink which lie behind it. H. 0'063 in. 

 B. 0-049. Mouth, height 0-032, breadth 0*028. 



I have called this a Bissoa, because, in the absence of the animal and its operculum, it is impos- 

 sible to put it anywhere with certainty, but I do not believe it to belong to this genus. It is very 

 like Assiminea litorina (Chiaje), but is slightly slimmer, the last whorl is less tumid than in that 

 species, so that a shell of four whorls in this is just about the size of one of three in that ; it has no 

 spirals, the top of the mouth is not acute, but only barely angulated ; the apex is a little more 

 rounded ; the spire a little less scalar ; and there is a minute umbilical chink. 



44. Rissoa (Setia) sinapi, 1 n. sp. (PI. XLV. fig. 13). 

 January 19-20, 1874. Koyal Sound, Kerguelen. Shore. 



Shell. — Very small, strongish, ovate, ruddily horny, smooth, with a blunt rounded tip, 

 convex whorls, a linear suture, a flatly rounded base, an unvarixed lip, and a round 



1 So called from its small size. 



