Description Description.Test trochospiral, unequally
biconvex, subcircular in outline recognized
easily by its clear wall showing a cloudy
mottling under a light microscope; spiral
side evolute, slightly convex; umbilical
side involute, more strongly convex;
peripheral margin strongly keeled; on the
spiral side, sutures flush, indistinct,
obscured by irregularly distributed, low
tubercles; on the umbilical side, 7-9 somewhat
inflated chambers with depressed
and nearly radiate sutures; wall finely
perforated on both sides; apertural face
truncate, with an acute, nearly keeled
border; aperture one or two small openings
at the base of the apertural chamber
and a long slit-like peripheral opening
parallel to the margin and provided with
a prominent inner lip, still visible on the
last 3 or 4 chambers.Author Debenay, Jean-Pierre· JPG file - 4.20 MB - 4 016 x 4 016 pixels
Extra information Original Width: 4016 pixels Original Height: 4016 pixels Orientation: 1: Normal (0 deg)