KEPORT ON THE GASTEROPODA. 597 



Mouth slightly oblique, irregularly pear-shaped, the curve of the iuuer and outer lip being 

 dissimilar ; it is slightly pointed above, and also at the point of the pillar. Outer lip 

 thickened by the varix, but bevelled to a thin edge, which is fairly level ; in direction it 

 is equally curved throughout ; on the base it is patulous, above slightly inverted. Inner 

 lip thin, on the pillar sharp, concave throughout. H. - 0G2 in. B. 0'04. Mouth, height 

 0-027, breadth 0-024. 



This species in form resembles a sharp-tipped Eissoa subsoluta, Aradas, while its sculpture is 

 intermediate between Eissoa abyssicola, Forbes (Rissoa testa, var. ?, Aradas and Magg.), and Eissoa 

 dcliciosa, Jeffr. 



19. Rissoa (Alvania) luscinia, 1 n. sp. (PL XL1V. fig. 3). 



Station 135c. October 17, 1873. Lat. 37° 25' 30" S., long. 12° 28' 30" W. Nightin- 

 gale Island, off Tristan da Cunha. 100 to 150 fathoms. 



Shell. — Oblong, broadish, conical, blunt tipped, white, with spiral threads, a deepish 

 suture, and a large round patulous mouth. Sculpture : Longitudinals— on the upper whorls, 

 especially on the penultimate, there are about 16 broadish blunt low ribs, forming blunt 

 tubercles on the spirals ; on the last whorl these become very faint. Spirals — on the last 

 whorl there are about nine fine distinct raised equally distant threads, of which three 

 occupy the base ; they are parted by broadish open furrows. Colour a uniform yellow 

 glossy white. Spire elevated, conical. Apex blunt, the extreme tip rising like a small 

 smooth dome on one side of the flat top. Whorls 5, very convex ; the first 3^ are of 

 slow and regular increase ; the last is much longer than the rest. Suture deeply impressed, 

 and not much oblique. Mouth large, round, open, parallel to the axis. Outer lip patulous, 

 with a sharp edge strengthened by an external varix ; its sweep is rounded ; in the middle 

 it is prominent, retreating a little at its origin and at the point of the pillar, so as to form 

 a slight Rissoina-like channel at these two points. Inner lip pretty strong on the body ; 

 on the pillar it projects as a sharpish lamina, which is continued round the outer circum- 

 ference of the mouth. H. 0-09 in. B. 0'04. Mouth, height 0-034, breadth 0*029. 



This species is extremely like Eissoa carribwa, d'Orb., in form, but the sculpture is different, 

 and the whorls are a little less swollen. 



C. Spiralled strongly (Onoba), i.e., in which the spiral threads are the striking feature. 



20. Eissoa (Onoba) fenestrata, Krauss. 



Rissoa fenestrata, Krauss, Siidafrik. Moll., p. 86, pi. v. fig. 20. 



So called from the name of the island. 



