REPORT ON THEXJASTEROPODA. 585 



Shell. — Rather long, conical, sharp-pointed, bluntly keeled, glossy, with a broad 

 spirally striated base, and a biangulated mouth. Sculpture : Longitudinals— the lines of 

 growth are microscopic and feeble. Spirals — there is round the base a blunt keel ; within 

 this the whole base is scored with strong flat threads, parted by narrow shallow furrows ; 

 the whole surface is covered with sharp microscopic scratches ; in a few cases the threads 

 and furrows of the base are simulated in colour on the side of the body-whorl. Colour of 

 a ruddy sandy hue to porcellanous white. Spire conical, high. Apex small, consisting 

 of two turbinated whorls, the extreme tip of which is slightly prominent and quite smooth. 

 Whorls 8, rather short, conical, barely convex on the side, constricted just at the suture, 

 over which the whorl has a slight tendency to project, giving the impression of a faint 

 imbrication of the whorls, 1 the last is bluntly angulated at the periphery, and has a flatly 

 conical base. Suture slightly angularly impressed. Mouth oval, pointed above, and also 

 at the front of the pillar. Outer lip sharp and thin, slightly bent in above, straight to 

 the basal angulation, whence it is arched and patulous to the point of the pillar, where it 

 is angulated and prominent. Inner lip rather thin on the body, barely angulated at the 

 base of the pillar, which is slightly oblique, with a thin patulous edge ; behind the pillar 

 is a minute umbilical chink. H. O'll in. B. 0'05. Mouth, height 0-042, breadth 0*029. 



This species, which seems plentiful, varies considerably in size. In the absence of the animal 

 and operculum its generic place is, of course, very doubtfully determined ; but the form of the 

 mouth seems to connect it rather with Barlccia than with the Cingula group of Rissoa. 



Family RissoiDiE, Gray, 1840. 



Genera. 1. Rissoa, Fremenville. 2. Hydrobia, Hartmann. 3. Eatoniella, Dall. 4. Rissoina, d'Orbigny. 

 5. Fenella, A. Adams. 6. Scaliola, A. Adams. 7. Skenea, Fleming. 



1. Rissoa, Fremenville, 1814. 

 Species. 



A. Ribbed (Rissoa), i.e., of which the longi- B. Reticulated (Alvania), i.e., ribs and spirals 



tudinal ribs are the striking feature. pretty equal in strength. 



1. Rissoa costulata, Alder. 10. Rissoa (Alvania) calathus, Forb. and Han. 



2. Rissoa delieiosa, Jeffr. 11. Rissoa (Alvania) caneellata (Da Costa). 



3. Rissoa similis, Scacchi. 12. Rissoa (Alvania) canariensis, d'Orb., with var. 



4. Rissoa pyrrhias, n. sp. of Manzoni. 



5. Rissoa xanthias, n. sp. 13. Rissoa (Alvania) hispidula, Monterosato. 



6. Rissoa fayalensis, n. sp. 14. Rissoa (Alvania) costata (J. Ad.) 



7. Rissoa amblia, n. sp. 15. Rissoa (Alvania) leacoeki, Wats. 



8. Rissoa pernambucensis, n. sp. 16. Rissoa (Alvania) didyma, n. sp. 



9. Rissoa microstoma, n. sp. 17. Rissoa (Alvania) tarsodes, n. sp. 



1 Hence the name. 



(ZOOL. CHALL. EXP. — PABT XLIL — 1885.) Tt 74 



