420 . FUNAFUTI ATOLL. 
Island. These measure 5 mm. in length, and have an additional 
spiral cord. 
Though certainly distinct, R. transenna, Watson, has much 
resemblance to this species. &. clathrata, Adams, appears to 
differ slightly by coarser sculpture. 
RissoOINA GEMMEA, sp. nov. 
(Fig. 11). 
Shell narrow, conical, white. Whorls eight (including two em- 
bryonic), rounded, suture lightly impressed. Embryonic whorls 
smooth, shining, apparently two, but a study of several species of 
the genus suggests that the topmost apparent 
whorl may contain several whorls wound in the 
same plane and concealed within the outermost. 
Sculpture—the last whorl is evenly and closely 
latticed by the intersection of eleven slender 
spiral cords, and about forty-two delicate longi- 
tudinal ribs ; a smooth shining bead marks each 
crossing of the sculpture. The longitudinal ribs 
are slightly stronger than the spiral cords, a - 
quarter of the breadth of their interstices, 
slightly oblique and curved; they cross regularly 
from base to suture and continue without stop- 
page at the suture, from whorl to whorl of the 
spire. Ascending the upper whorls, the spiral 
cords become fewer and gradually vanish leaving 
as vestiges a fewdenticles.on the ribs. The spaces 
enclosed by the majorsculpture are square shallow 
Fig. 11. pits, spirally striated. Round the base are wound 
three or four irregularly beaded cords. 
Aperture oblique, produced in front, contracted anteriorly to a 
short spout; columella sharply recurved at the base, extending 
across the body-whorl as a thick layer of callus ; posteriorly the 
lip is sharply folded at its junction with the body whorl. The 
outer lip is much thickened, grooved upon the inner face, denticu- 
late on the profile and with a heavy callus behind. Length 4, 
breadth 14 mm. 
One specimen in shallow water in the lagoon. 
In this species the grains seem to be smaller and more numerous 
than in any other beaded Rissoina described. 
RIsSOINA POLYTROPA, sp. nov. 
(Fig. 12). 
Shell ovate, fusiform, narrow, white. Suture impressed, Whorls 
seven, including two embryonic. The last whorl descends from 
the spiral plane of its predecessors until reaching the aperture, 
when it ascends suddenly and rapidly, the varix mounting up the 
preceding whorl for three tiers of spiral lyre. The shell is thus 
