Volutions, the wreaths or turnings of the shells of univalves.
Urceolate, swelling in the middle like a pitcher.
Vulva, a spatulated mark in several bivalve shells; formed when the valves are united on the posterior and anterior slopes.
W.
Whorl, one of the wreaths or turnings of the spire of univalves.
Z.
Zigzag, having contrary turnings and windings.
Zoned, surrounded with one or more girdles.
INDEX
TO THE
CLASSES, FAMILIES, GENERA, AND PLATES.
[N.B.—The Classes are printed in Small Capitals, the Families in Italics, and the Genera in the Ordinary Type.]