Mr. E. Waller on a new British Species of Rissoa. 137 
Whorls 5-6, sloping from the suture to the second ridge, and 
‘well rounded thence to the lower suture; the last whorl 
exceeding half the length of the shell, and obliquely 
rounded at the base. 
Sculpture: on the penultimate whorl four rather slender but 
well-defined spiral ridges, the lower three of which are 
stronger than the highest one, which is on the upper slope 
of the whorl. The ridges are crossed by about twenty- 
eight perpendicular ribs, not so much elevated nor nearly 
so strong as the ridges, and forming with them square 
cancellations, the intersections of the ridges and ribs being 
scarcely raised, but slightly nodulous. The apical whorls 
are marked with spiral rows of close angular punctures. 
In each succeeding row the punctures lie below the ridges 
separating those of the preceding row. The base of the 
lowest whorl has 5-7 spiral ridges, for the most part un- 
crossed by the ribs, which generally terminate at the line 
of the upper part of the mouth. 
Suture deeply defined and somewhat excavated. 
Mouth roundish oval. 
Outer li smooth inside, and strengthened outside by a broad 
and strong rib. , 
Inner lip smooth and reflected on the pillar, making the peri- 
stome continuous. 
Umbilical chink very small. 
Length 0°10 inch, breadth 0:07 inch. 
Its nearest ally is Rissoa cimicoides, Forbes (Rissoa sculpta of 
F, & H., but not of Philippi); but it differs from that species 
in being of smaller size and of thinner texture, in having the 
whorls more rounded and with a rapid slope from the deep 
suture to the second rib. The general outline is decidedly less 
conical ; and while the longitudinal ribs are much the stronger 
in R. cimicoides, the transverse ones are stronger in R. Jeffreysi, 
and the nodules at the intersections are much larger in the 
former than in the latter shell. In the present species the 
sculpture is infinitely more delicate than in its ally. The throat 
is crenulated in R. czmicoides, but smooth in R. Jeffreysi.  R. 
cimicoides is yellow, with purplish-brown blotches; R. Jeffreys: 
is porcelain-white. 
Its habitat is mm sandy ground, in from 80 to 85 fathoms ; 
and it has been taken in two localities at about eight miles and 
thirty miles from Unst, the most northern of the Shetland 
Islands. 
Mr. Jeffreys informs me that, when in Scandinavia, last year, 
he saw two or three specimens in the Museum at Upsala, col- 
