REPORT ON THE GASTEROPODA. 58.9 



Shell. — Thin, ovate-oblong, conical, glossy, translucent white, continuously ribbed, 

 with a row of rather sharp tubercles just below the suture, flat whorls, a bluntly angulated 

 rounded base, and an oval thin-lipped mouth. Sculpture : Longitudinals — there are from 

 12 to 16 ribs, which run continuously from whorl to whorl, and tend to become obsolete 

 and sparse on the last whorl ; at the top of each whorl these ribs take their rise in a small 

 prominent tubercle ; on the base they disappear. Spirals — there are traces, generally 

 feeble above, but much stronger on the base, of close flat rounded threads, which die out 

 in the middle of the base. Colour translucent white, scarcely glossy. Spire conical. 

 Apex conical ; it consists of four tawny or yellow embryonic whorls, convex, angulated, 

 the last scored below with three granulated spirals, where the convexity exists ; the third 

 and second have two of these spirals ; above these spirals the individual whorls contract 

 rapidly, with a slightly concave outline ; the tip is smooth, and relatively to the others 

 a little large. Whorls 7, flattened on the sides, conical, of rather rapid increase. 

 Suture linear, slightly impressed. Mouth largish, oval, pointed above, a little oblique. 

 Outer lip thin, unvarixed, somewhat patulous in front. Inner lip thin on the body, sharp 

 and prominent at the pillar, where a slight umbilical groove lies behind it. H. 0*084 in. 

 B. 0-045. Mouth, height 0"033, breadth 0-03. 



This species at first sight greatly resembles Rissoa pyrrhias, Wats., but is smaller, is slightly 

 different in form, being longer in proportion to breadth, and has no labral varix ; but the most 

 marked difference lies in the apex of the two shells, which, very like in colour, differ in form, in 

 sculpture, and in number of whorls. 



6. Rissoa fayalensis, n. sp. (PL XLIV. fig. 7). 



Station 75. July 2, 1873. Lat. 3S° 38' N., long. 28° 28' 30" W. Off Fayal, Azores. 

 450 to 500 fathoms. Volcanic mud. 



Shell. — Thin, ovate, conical, translucent white, remotely ribbed, with conical whorls 

 and a blunt tip. Sculpture : Longitudinals — there are about 12 sharpish, narrow, nearly 

 continuous, but slightly irregular, faintly curved ribs, which die out rather suddenly at the 

 base. Spirals — on the base there are about six remote rather feeble threads. Colour 

 translucent white. Spire conical, short. Apex very blunt, the two embryonic whorls 

 being rather large, and depressedly rounded ; they are quite smooth. Whorls 5, convexly 

 conical, very slightly constricted round the bottom ; they are of regular increase ; the last 

 one is very bluntly angulated round the base. Suture linear, with a very slight constric- 

 tion ; a little oblique. Mouth largish, oval, very slightly pointed above. . Outer Up a 

 little straight above, rounded on the base. Inner lip very thin on the body, narrow and 

 scarcely prominent on the pillar, where there is the minutest possible umbilical furrow. 

 H. 0068 in. B. 0-04. Mouth, height 0'03, breadth 0-022. 



