MOLLUSC A OF THE ' CHALLENGES' EXPEDITION. 99 



Jefebeysia, Alder. 



Jeffeeysia edwabdiensis, n. sp. 



St. 145 a. Dec. 27, 1873. Lat. 46° 41' S., long. 38° 10' E. 

 Prince Edward Island, between Cape of Good Hope and Ker- 

 guelen. 50 to 150 fms. 



Shell. — Tumidly conical, flattish on the base, thin, glassy. 

 Sculpture. The whole glossy surface is covered with extremely 

 fine lines of growth, and with still fainter and more minute spirals, 

 which are only vaguely discernible under the microscope and in 

 very favourable light. Colour whitish, hyaline. Spire conical. 

 Apex bluntish, and a little obliquely rounded. Whorls 4|, tumidly 

 convex or rounded, of regular increase until the last, which is 

 somewhat disproportionately swollen. Suture rather shallow and 

 open. Mouth perpendicular, oval, rather large. Outer lip sharp 

 and thin, with a slight sinus at its junction with the body ; incurved 

 above, slightly flattened in the middle, advancing below, patulous 

 and longitudinally prominent, but slightly sinuated towards the 

 point of the pillar. Inner lip just connected with the outer by a 

 film across the body, closely and shortly bent back on the um- 

 bilicus, and sharp on the edge of the pillar. Pillar straight, 

 angulately springing from the body-whorl, bending a little to the 

 left. Umbilicus a minute chink, almost covered by the inner lip. 

 H. 0-075. B. 0-048, least 0-04. Penultimate whorl 0-017. 

 Mouth, length 0-037, breadth 0-028. 



The general aspect of this shell resembles that of Jeffreysia, but 

 the inner lip by no means presents so continuous a peristome as 

 any of our British species of the genus, and the junction of the 

 pillar to the body is quite distinctly angulated, which is not the 

 case in any Jeffreysia known to me. If assigned to this genus, 

 therefore, it is rather because none else lies nearer, and in the 

 absence of the animal and of the operculum, a new genus would 

 be absurd here. 



Cebithium (Adanson), Brug. 



1. C. (Triforis) levukense, n. sp. 12. C. (-5.) luscince, n. sp. 



2. C. (T.) bigemma, n. sp. 13. C. (B.) philomelce, n. sp. 



3. C. (T.) hebes, n. sp. 14. C. (B.) gemmatum, n. sp. 



4. C. (T.) inflatum, n. sp. 15. C. (B.) pupiforme, n. sp. 



5. C. matufcense, n. sp. 16. C. (-B.) enode, n. sp. 



6. C. phoocum, n. sp. 17. C. (B.) oosimense, n. sp.. 



7. C. (Bittium) lissum, n. sp. 18. C. (B.) cylindricum, n. sp. 



8. C. (B.) amblyterum, n. sp. 19. C. (B.) abruptum, n. sp. 



9. C. (B.) mamillanum, n. sp. 20. C. (B.) delicatum,n. sp. 



10. C. (B.) amboynense, n. sp. 21. C. (B.) a'edonium, n. sp. 



11. C. (B.) pigrum, n. sp. 



